Use CC:T's version of dan200.computercraft.core

src/main/java/dan200/computercraft/core/apis/ApiFactories.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.ILuaAPIFactory;
@@ -16,13 +15,13 @@ import java.util.Objects;
 
 public final class ApiFactories
 {
-    private static final Collection<ILuaAPIFactory> factories = new LinkedHashSet<>();
-    private static final Collection<ILuaAPIFactory> factoriesView = Collections.unmodifiableCollection( factories );
-
     private ApiFactories()
     {
     }
 
+    private static final Collection<ILuaAPIFactory> factories = new LinkedHashSet<>();
+    private static final Collection<ILuaAPIFactory> factoriesView = Collections.unmodifiableCollection( factories );
+
     public static synchronized void register( @Nonnull ILuaAPIFactory factory )
     {
         Objects.requireNonNull( factory, "provider cannot be null" );

src/main/java/dan200/computercraft/core/apis/ComputerAccess.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.filesystem.IMount;
@@ -20,22 +19,22 @@ import java.util.Set;
 
 public abstract class ComputerAccess implements IComputerAccess
 {
-    private final IAPIEnvironment m_environment;
-    private final Set<String> m_mounts = new HashSet<>();
+    private final IAPIEnvironment environment;
+    private final Set<String> mounts = new HashSet<>();
 
     protected ComputerAccess( IAPIEnvironment environment )
     {
-        this.m_environment = environment;
+        this.environment = environment;
     }
 
     public void unmountAll()
     {
-        FileSystem fileSystem = this.m_environment.getFileSystem();
-        for( String mount : this.m_mounts )
+        FileSystem fileSystem = environment.getFileSystem();
+        for( String mount : mounts )
         {
             fileSystem.unmount( mount );
         }
-        this.m_mounts.clear();
+        mounts.clear();
     }
 
     @Override
@@ -47,15 +46,12 @@ public abstract class ComputerAccess implements IComputerAccess
 
         // Mount the location
         String location;
-        FileSystem fileSystem = this.m_environment.getFileSystem();
-        if( fileSystem == null )
-        {
-            throw new IllegalStateException( "File system has not been created" );
-        }
+        FileSystem fileSystem = environment.getFileSystem();
+        if( fileSystem == null ) throw new IllegalStateException( "File system has not been created" );
 
         synchronized( fileSystem )
         {
-            location = this.findFreeLocation( desiredLoc );
+            location = findFreeLocation( desiredLoc );
             if( location != null )
             {
                 try
@@ -68,10 +64,7 @@ public abstract class ComputerAccess implements IComputerAccess
             }
         }
 
-        if( location != null )
-        {
-            this.m_mounts.add( location );
-        }
+        if( location != null ) mounts.add( location );
         return location;
     }
 
@@ -84,15 +77,12 @@ public abstract class ComputerAccess implements IComputerAccess
 
         // Mount the location
         String location;
-        FileSystem fileSystem = this.m_environment.getFileSystem();
-        if( fileSystem == null )
-        {
-            throw new IllegalStateException( "File system has not been created" );
-        }
+        FileSystem fileSystem = environment.getFileSystem();
+        if( fileSystem == null ) throw new IllegalStateException( "File system has not been created" );
 
         synchronized( fileSystem )
         {
-            location = this.findFreeLocation( desiredLoc );
+            location = findFreeLocation( desiredLoc );
             if( location != null )
             {
                 try
@@ -105,59 +95,46 @@ public abstract class ComputerAccess implements IComputerAccess
             }
         }
 
-        if( location != null )
-        {
-            this.m_mounts.add( location );
-        }
+        if( location != null ) mounts.add( location );
         return location;
     }
 
     @Override
     public void unmount( String location )
     {
-        if( location == null )
-        {
-            return;
-        }
-        if( !this.m_mounts.contains( location ) )
-        {
-            throw new IllegalStateException( "You didn't mount this location" );
-        }
+        if( location == null ) return;
+        if( !mounts.contains( location ) ) throw new IllegalStateException( "You didn't mount this location" );
 
-        this.m_environment.getFileSystem()
-            .unmount( location );
-        this.m_mounts.remove( location );
+        environment.getFileSystem().unmount( location );
+        mounts.remove( location );
     }
 
     @Override
     public int getID()
     {
-        return this.m_environment.getComputerID();
+        return environment.getComputerID();
     }
 
     @Override
     public void queueEvent( @Nonnull String event, Object... arguments )
     {
         Objects.requireNonNull( event, "event cannot be null" );
-        this.m_environment.queueEvent( event, arguments );
+        environment.queueEvent( event, arguments );
     }
 
     @Nonnull
     @Override
     public IWorkMonitor getMainThreadMonitor()
     {
-        return this.m_environment.getMainThreadMonitor();
+        return environment.getMainThreadMonitor();
     }
 
     private String findFreeLocation( String desiredLoc )
     {
         try
         {
-            FileSystem fileSystem = this.m_environment.getFileSystem();
-            if( !fileSystem.exists( desiredLoc ) )
-            {
-                return desiredLoc;
-            }
+            FileSystem fileSystem = environment.getFileSystem();
+            if( !fileSystem.exists( desiredLoc ) ) return desiredLoc;
 
             // We used to check foo2, foo3, foo4, etc here but the disk drive does this itself now
             return null;

src/main/java/dan200/computercraft/core/apis/FSAPI.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.IArguments;
@@ -42,7 +41,7 @@ public class FSAPI implements ILuaAPI
 
     public FSAPI( IAPIEnvironment env )
     {
-        this.environment = env;
+        environment = env;
     }
 
     @Override
@@ -54,13 +53,13 @@ public class FSAPI implements ILuaAPI
     @Override
     public void startup()
     {
-        this.fileSystem = this.environment.getFileSystem();
+        fileSystem = environment.getFileSystem();
     }
 
     @Override
     public void shutdown()
     {
-        this.fileSystem = null;
+        fileSystem = null;
     }
 
     /**
@@ -73,10 +72,10 @@ public class FSAPI implements ILuaAPI
     @LuaFunction
     public final String[] list( String path ) throws LuaException
     {
-        this.environment.addTrackingChange( TrackingField.FS_OPS );
+        environment.addTrackingChange( TrackingField.FS_OPS );
         try
         {
-            return this.fileSystem.list( path );
+            return fileSystem.list( path );
         }
         catch( FileSystemException e )
         {
@@ -86,7 +85,7 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Combines several parts of a path into one full path, adding separators as
-     * needed
+     * needed.
      *
      * @param arguments The paths to combine.
      * @return The new path, with separators added between parts as needed.
@@ -146,7 +145,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            return this.fileSystem.getSize( path );
+            return fileSystem.getSize( path );
         }
         catch( FileSystemException e )
         {
@@ -165,7 +164,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            return this.fileSystem.exists( path );
+            return fileSystem.exists( path );
         }
         catch( FileSystemException e )
         {
@@ -184,7 +183,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            return this.fileSystem.isDir( path );
+            return fileSystem.isDir( path );
         }
         catch( FileSystemException e )
         {
@@ -203,7 +202,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            return this.fileSystem.isReadOnly( path );
+            return fileSystem.isReadOnly( path );
         }
         catch( FileSystemException e )
         {
@@ -222,8 +221,8 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            this.environment.addTrackingChange( TrackingField.FS_OPS );
-            this.fileSystem.makeDir( path );
+            environment.addTrackingChange( TrackingField.FS_OPS );
+            fileSystem.makeDir( path );
         }
         catch( FileSystemException e )
         {
@@ -245,8 +244,8 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            this.environment.addTrackingChange( TrackingField.FS_OPS );
-            this.fileSystem.move( path, dest );
+            environment.addTrackingChange( TrackingField.FS_OPS );
+            fileSystem.move( path, dest );
         }
         catch( FileSystemException e )
         {
@@ -268,8 +267,8 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            this.environment.addTrackingChange( TrackingField.FS_OPS );
-            this.fileSystem.copy( path, dest );
+            environment.addTrackingChange( TrackingField.FS_OPS );
+            fileSystem.copy( path, dest );
         }
         catch( FileSystemException e )
         {
@@ -280,7 +279,8 @@ public class FSAPI implements ILuaAPI
     /**
      * Deletes a file or directory.
      *
-     * If the path points to a directory, all of the enclosed files and subdirectories are also deleted.
+     * If the path points to a directory, all of the enclosed files and
+     * subdirectories are also deleted.
      *
      * @param path The path to the file or directory to delete.
      * @throws LuaException If the file or directory couldn't be deleted.
@@ -290,8 +290,8 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            this.environment.addTrackingChange( TrackingField.FS_OPS );
-            this.fileSystem.delete( path );
+            environment.addTrackingChange( TrackingField.FS_OPS );
+            fileSystem.delete( path );
         }
         catch( FileSystemException e )
         {
@@ -304,8 +304,10 @@ public class FSAPI implements ILuaAPI
     /**
      * Opens a file for reading or writing at a path.
      *
-     * The mode parameter can be {@code r} to read, {@code w} to write (deleting all contents), or {@code a} to append (keeping contents). If {@code b} is
-     * added to the end, the file will be opened in binary mode; otherwise, it's opened in text mode.
+     * The mode parameter can be {@code r} to read, {@code w} to write (deleting
+     * all contents), or {@code a} to append (keeping contents). If {@code b} is
+     * added to the end, the file will be opened in binary mode; otherwise, it's
+     * opened in text mode.
      *
      * @param path The path to the file to open.
      * @param mode The mode to open the file with.
@@ -318,7 +320,7 @@ public class FSAPI implements ILuaAPI
     @LuaFunction
     public final Object[] open( String path, String mode ) throws LuaException
     {
-        this.environment.addTrackingChange( TrackingField.FS_OPS );
+        environment.addTrackingChange( TrackingField.FS_OPS );
         try
         {
             switch( mode )
@@ -326,37 +328,37 @@ public class FSAPI implements ILuaAPI
                 case "r":
                 {
                     // Open the file for reading, then create a wrapper around the reader
-                    FileSystemWrapper<BufferedReader> reader = this.fileSystem.openForRead( path, EncodedReadableHandle::openUtf8 );
+                    FileSystemWrapper<BufferedReader> reader = fileSystem.openForRead( path, EncodedReadableHandle::openUtf8 );
                     return new Object[] { new EncodedReadableHandle( reader.get(), reader ) };
                 }
                 case "w":
                 {
                     // Open the file for writing, then create a wrapper around the writer
-                    FileSystemWrapper<BufferedWriter> writer = this.fileSystem.openForWrite( path, false, EncodedWritableHandle::openUtf8 );
+                    FileSystemWrapper<BufferedWriter> writer = fileSystem.openForWrite( path, false, EncodedWritableHandle::openUtf8 );
                     return new Object[] { new EncodedWritableHandle( writer.get(), writer ) };
                 }
                 case "a":
                 {
                     // Open the file for appending, then create a wrapper around the writer
-                    FileSystemWrapper<BufferedWriter> writer = this.fileSystem.openForWrite( path, true, EncodedWritableHandle::openUtf8 );
+                    FileSystemWrapper<BufferedWriter> writer = fileSystem.openForWrite( path, true, EncodedWritableHandle::openUtf8 );
                     return new Object[] { new EncodedWritableHandle( writer.get(), writer ) };
                 }
                 case "rb":
                 {
                     // Open the file for binary reading, then create a wrapper around the reader
-                    FileSystemWrapper<ReadableByteChannel> reader = this.fileSystem.openForRead( path, Function.identity() );
+                    FileSystemWrapper<ReadableByteChannel> reader = fileSystem.openForRead( path, Function.identity() );
                     return new Object[] { BinaryReadableHandle.of( reader.get(), reader ) };
                 }
                 case "wb":
                 {
                     // Open the file for binary writing, then create a wrapper around the writer
-                    FileSystemWrapper<WritableByteChannel> writer = this.fileSystem.openForWrite( path, false, Function.identity() );
+                    FileSystemWrapper<WritableByteChannel> writer = fileSystem.openForWrite( path, false, Function.identity() );
                     return new Object[] { BinaryWritableHandle.of( writer.get(), writer ) };
                 }
                 case "ab":
                 {
                     // Open the file for binary appending, then create a wrapper around the reader
-                    FileSystemWrapper<WritableByteChannel> writer = this.fileSystem.openForWrite( path, true, Function.identity() );
+                    FileSystemWrapper<WritableByteChannel> writer = fileSystem.openForWrite( path, true, Function.identity() );
                     return new Object[] { BinaryWritableHandle.of( writer.get(), writer ) };
                 }
                 default:
@@ -365,10 +367,7 @@ public class FSAPI implements ILuaAPI
         }
         catch( FileSystemException e )
         {
-            return new Object[] {
-                null,
-                e.getMessage()
-            };
+            return new Object[] { null, e.getMessage() };
         }
     }
 
@@ -385,7 +384,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            return this.fileSystem.exists( path ) ? new Object[] { this.fileSystem.getMountLabel( path ) } : null;
+            return fileSystem.exists( path ) ? new Object[] { fileSystem.getMountLabel( path ) } : null;
         }
         catch( FileSystemException e )
         {
@@ -394,7 +393,8 @@ public class FSAPI implements ILuaAPI
     }
 
     /**
-     * Returns the amount of free space available on the drive the path is located on.
+     * Returns the amount of free space available on the drive the path is
+     * located on.
      *
      * @param path The path to check the free space for.
      * @return The amount of free space available, in bytes.
@@ -406,7 +406,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            long freeSpace = this.fileSystem.getFreeSpace( path );
+            long freeSpace = fileSystem.getFreeSpace( path );
             return freeSpace >= 0 ? freeSpace : "unlimited";
         }
         catch( FileSystemException e )
@@ -418,8 +418,10 @@ public class FSAPI implements ILuaAPI
     /**
      * Searches for files matching a string with wildcards.
      *
-     * This string is formatted like a normal path string, but can include any number of wildcards ({@code *}) to look for files matching anything. For
-     * example, {@code rom/* /command*} will look for any path starting with {@code command} inside any subdirectory of {@code /rom}.
+     * This string is formatted like a normal path string, but can include any
+     * number of wildcards ({@code *}) to look for files matching anything.
+     * For example, {@code rom/* /command*} will look for any path starting with
+     * {@code command} inside any subdirectory of {@code /rom}.
      *
      * @param path The wildcard-qualified path to search for.
      * @return A list of paths that match the search string.
@@ -430,8 +432,8 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            this.environment.addTrackingChange( TrackingField.FS_OPS );
-            return this.fileSystem.find( path );
+            environment.addTrackingChange( TrackingField.FS_OPS );
+            return fileSystem.find( path );
         }
         catch( FileSystemException e )
         {
@@ -442,20 +444,22 @@ public class FSAPI implements ILuaAPI
     /**
      * Returns true if a path is mounted to the parent filesystem.
      *
-     * The root filesystem "/" is considered a mount, along with disk folders and the rom folder. Other programs (such as network shares) can extend this to
-     * make other mount types by correctly assigning their return value for getDrive.
+     * The root filesystem "/" is considered a mount, along with disk folders and the rom folder. Other programs
+     * (such as network shares) can extend this to make other mount types by correctly assigning their return value for
+     * getDrive.
      *
      * @param path The path of the drive to get.
      * @return The drive's capacity.
      * @throws LuaException If the capacity cannot be determined.
-     * @cc.treturn number|nil This drive's capacity. This will be nil for "read-only" drives, such as the ROM or treasure disks.
+     * @cc.treturn number|nil This drive's capacity. This will be nil for "read-only" drives, such as the ROM or
+     * treasure disks.
      */
     @LuaFunction
     public final Object getCapacity( String path ) throws LuaException
     {
         try
         {
-            OptionalLong capacity = this.fileSystem.getCapacity( path );
+            OptionalLong capacity = fileSystem.getCapacity( path );
             return capacity.isPresent() ? capacity.getAsLong() : null;
         }
         catch( FileSystemException e )
@@ -470,8 +474,8 @@ public class FSAPI implements ILuaAPI
      * The returned attributes table contains information about the size of the file, whether it is a directory,
      * when it was created and last modified, and whether it is read only.
      *
-     * The creation and modification times are given as the number of milliseconds since the UNIX epoch. This may be given to {@link OSAPI#date} in order to
-     * convert it to more usable form.
+     * The creation and modification times are given as the number of milliseconds since the UNIX epoch. This may be
+     * given to {@link OSAPI#date} in order to convert it to more usable form.
      *
      * @param path The path to get attributes for.
      * @return The resulting attributes.
@@ -485,7 +489,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            BasicFileAttributes attributes = this.fileSystem.getAttributes( path );
+            BasicFileAttributes attributes = fileSystem.getAttributes( path );
             Map<String, Object> result = new HashMap<>();
             result.put( "modification", getFileTime( attributes.lastModifiedTime() ) );
             result.put( "modified", getFileTime( attributes.lastModifiedTime() ) );

src/main/java/dan200/computercraft/core/apis/HTTPAPI.java

@@ -37,7 +37,7 @@ public class HTTPAPI implements ILuaAPI
 {
     private final IAPIEnvironment apiEnvironment;
 
-    private final ResourceGroup<CheckUrl> checkUrls = new ResourceGroup<>();
+    private final ResourceGroup<CheckUrl> checkUrls = new ResourceGroup<>( ResourceGroup.DEFAULT );
     private final ResourceGroup<HttpRequest> requests = new ResourceQueue<>( () -> ComputerCraft.httpMaxRequests );
     private final ResourceGroup<Websocket> websockets = new ResourceGroup<>( () -> ComputerCraft.httpMaxWebsockets );
 
@@ -127,7 +127,10 @@ public class HTTPAPI implements ILuaAPI
             HttpRequest request = new HttpRequest( requests, apiEnvironment, address, postString, headers, binary, redirect );
 
             // Make the request
-            request.queue( r -> r.request( uri, httpMethod ) );
+            if( !request.queue( r -> r.request( uri, httpMethod ) ) )
+            {
+                throw new LuaException( "Too many ongoing HTTP requests" );
+            }
 
             return new Object[] { true };
         }
@@ -138,12 +141,15 @@ public class HTTPAPI implements ILuaAPI
     }
 
     @LuaFunction
-    public final Object[] checkURL( String address )
+    public final Object[] checkURL( String address ) throws LuaException
     {
         try
         {
             URI uri = HttpRequest.checkUri( address );
-            new CheckUrl( checkUrls, apiEnvironment, address, uri ).queue( CheckUrl::run );
+            if( !new CheckUrl( checkUrls, apiEnvironment, address, uri ).queue( CheckUrl::run ) )
+            {
+                throw new LuaException( "Too many ongoing checkUrl calls" );
+            }
 
             return new Object[] { true };
         }

src/main/java/dan200/computercraft/core/apis/IAPIEnvironment.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -21,6 +20,12 @@ public interface IAPIEnvironment
 {
     String TIMER_EVENT = "timer";
 
+    @FunctionalInterface
+    interface IPeripheralChangeListener
+    {
+        void onPeripheralChanged( ComputerSide side, @Nullable IPeripheral newPeripheral );
+    }
+
     int getComputerID();
 
     @Nonnull
@@ -65,16 +70,10 @@ public interface IAPIEnvironment
 
     void cancelTimer( int id );
 
-    default void addTrackingChange( @Nonnull TrackingField field )
-    {
-        this.addTrackingChange( field, 1 );
-    }
-
     void addTrackingChange( @Nonnull TrackingField field, long change );
 
-    @FunctionalInterface
-    interface IPeripheralChangeListener
+    default void addTrackingChange( @Nonnull TrackingField field )
     {
-        void onPeripheralChanged( ComputerSide side, @Nullable IPeripheral newPeripheral );
+        addTrackingChange( field, 1 );
     }
 }

src/main/java/dan200/computercraft/core/apis/LuaDateTime.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.LuaException;
@@ -21,9 +20,6 @@ import java.util.function.LongUnaryOperator;
 
 final class LuaDateTime
 {
-    private static final TemporalField CENTURY = map( ChronoField.YEAR, ValueRange.of( 0, 6 ), x -> (x / 100) % 100 );
-    private static final TemporalField ZERO_WEEK = map( WeekFields.SUNDAY_START.dayOfWeek(), ValueRange.of( 0, 6 ), x -> x - 1 );
-
     private LuaDateTime()
     {
     }
@@ -42,10 +38,7 @@ final class LuaDateTime
                     formatter.appendLiteral( c );
                     break;
                 case '%':
-                    if( i >= format.length() )
-                    {
-                        break;
-                    }
+                    if( i >= format.length() ) break;
                     switch( c = format.charAt( i++ ) )
                     {
                         default:
@@ -81,8 +74,7 @@ final class LuaDateTime
                             format( formatter, "%m/%d/%y", offset );
                             break;
                         case 'e':
-                            formatter.padNext( 2 )
-                                .appendValue( ChronoField.DAY_OF_MONTH );
+                            formatter.padNext( 2 ).appendValue( ChronoField.DAY_OF_MONTH );
                             break;
                         case 'F':
                             format( formatter, "%Y-%m-%d", offset );
@@ -97,7 +89,7 @@ final class LuaDateTime
                             formatter.appendValue( ChronoField.HOUR_OF_DAY, 2 );
                             break;
                         case 'I':
-                            formatter.appendValue( ChronoField.HOUR_OF_AMPM );
+                            formatter.appendValue( ChronoField.HOUR_OF_AMPM, 2 );
                             break;
                         case 'j':
                             formatter.appendValue( ChronoField.DAY_OF_YEAR, 3 );
@@ -176,49 +168,18 @@ final class LuaDateTime
         if( isDst != null )
         {
             boolean requireDst = isDst;
-            for( ZoneOffset possibleOffset : ZoneOffset.systemDefault()
-                .getRules()
-                .getValidOffsets( time ) )
+            for( ZoneOffset possibleOffset : ZoneOffset.systemDefault().getRules().getValidOffsets( time ) )
             {
                 Instant instant = time.toInstant( possibleOffset );
-                if( possibleOffset.getRules()
-                    .getDaylightSavings( instant )
-                    .isZero() == requireDst )
+                if( possibleOffset.getRules().getDaylightSavings( instant ).isZero() == requireDst )
                 {
                     return instant.getEpochSecond();
                 }
             }
         }
 
-        ZoneOffset offset = ZoneOffset.systemDefault()
-            .getRules()
-            .getOffset( time );
-        return time.toInstant( offset )
-            .getEpochSecond();
-    }
-
-    private static int getField( Map<?, ?> table, String field, int def ) throws LuaException
-    {
-        Object value = table.get( field );
-        if( value instanceof Number )
-        {
-            return ((Number) value).intValue();
-        }
-        if( def < 0 )
-        {
-            throw new LuaException( "field \"" + field + "\" missing in date table" );
-        }
-        return def;
-    }
-
-    private static Boolean getBoolField( Map<?, ?> table, String field ) throws LuaException
-    {
-        Object value = table.get( field );
-        if( value instanceof Boolean || value == null )
-        {
-            return (Boolean) value;
-        }
-        throw new LuaException( "field \"" + field + "\" missing in date table" );
+        ZoneOffset offset = ZoneOffset.systemDefault().getRules().getOffset( time );
+        return time.toInstant( offset ).getEpochSecond();
     }
 
     static Map<String, ?> toTable( TemporalAccessor date, ZoneId offset, Instant instant )
@@ -232,12 +193,28 @@ final class LuaDateTime
         table.put( "sec", date.getLong( ChronoField.SECOND_OF_MINUTE ) );
         table.put( "wday", date.getLong( WeekFields.SUNDAY_START.dayOfWeek() ) );
         table.put( "yday", date.getLong( ChronoField.DAY_OF_YEAR ) );
-        table.put( "isdst",
-            offset.getRules()
-                .isDaylightSavings( instant ) );
+        table.put( "isdst", offset.getRules().isDaylightSavings( instant ) );
         return table;
     }
 
+    private static int getField( Map<?, ?> table, String field, int def ) throws LuaException
+    {
+        Object value = table.get( field );
+        if( value instanceof Number ) return ((Number) value).intValue();
+        if( def < 0 ) throw new LuaException( "field \"" + field + "\" missing in date table" );
+        return def;
+    }
+
+    private static Boolean getBoolField( Map<?, ?> table, String field ) throws LuaException
+    {
+        Object value = table.get( field );
+        if( value instanceof Boolean || value == null ) return (Boolean) value;
+        throw new LuaException( "field \"" + field + "\" missing in date table" );
+    }
+
+    private static final TemporalField CENTURY = map( ChronoField.YEAR, ValueRange.of( 0, 6 ), x -> (x / 100) % 100 );
+    private static final TemporalField ZERO_WEEK = map( WeekFields.SUNDAY_START.dayOfWeek(), ValueRange.of( 0, 6 ), x -> x - 1 );
+
     private static TemporalField map( TemporalField field, ValueRange range, LongUnaryOperator convert )
     {
         return new TemporalField()
@@ -259,7 +236,7 @@ final class LuaDateTime
             @Override
             public ValueRange range()
             {
-                return this.range;
+                return range;
             }
 
             @Override
@@ -283,7 +260,7 @@ final class LuaDateTime
             @Override
             public ValueRange rangeRefinedBy( TemporalAccessor temporal )
             {
-                return this.range;
+                return range;
             }
 
             @Override

src/main/java/dan200/computercraft/core/apis/OSAPI.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.IArguments;
@@ -33,16 +32,36 @@ public class OSAPI implements ILuaAPI
 {
     private final IAPIEnvironment apiEnvironment;
 
-    private final Int2ObjectMap<Alarm> m_alarms = new Int2ObjectOpenHashMap<>();
-    private int m_clock;
-    private double m_time;
-    private int m_day;
+    private final Int2ObjectMap<Alarm> alarms = new Int2ObjectOpenHashMap<>();
+    private int clock;
+    private double time;
+    private int day;
 
-    private int m_nextAlarmToken = 0;
+    private int nextAlarmToken = 0;
+
+    private static class Alarm implements Comparable<Alarm>
+    {
+        final double time;
+        final int day;
+
+        Alarm( double time, int day )
+        {
+            this.time = time;
+            this.day = day;
+        }
+
+        @Override
+        public int compareTo( @Nonnull Alarm o )
+        {
+            double t = day * 24.0 + time;
+            double ot = day * 24.0 + time;
+            return Double.compare( t, ot );
+        }
+    }
 
     public OSAPI( IAPIEnvironment environment )
     {
-        this.apiEnvironment = environment;
+        apiEnvironment = environment;
     }
 
     @Override
@@ -54,252 +73,57 @@ public class OSAPI implements ILuaAPI
     @Override
     public void startup()
     {
-        this.m_time = this.apiEnvironment.getComputerEnvironment()
-            .getTimeOfDay();
-        this.m_day = this.apiEnvironment.getComputerEnvironment()
-            .getDay();
-        this.m_clock = 0;
+        time = apiEnvironment.getComputerEnvironment().getTimeOfDay();
+        day = apiEnvironment.getComputerEnvironment().getDay();
+        clock = 0;
 
-        synchronized( this.m_alarms )
+        synchronized( alarms )
         {
-            this.m_alarms.clear();
+            alarms.clear();
         }
     }
 
     @Override
     public void update()
     {
-        this.m_clock++;
+        clock++;
 
         // Wait for all of our alarms
-        synchronized( this.m_alarms )
+        synchronized( alarms )
         {
-            double previousTime = this.m_time;
-            int previousDay = this.m_day;
-            double time = this.apiEnvironment.getComputerEnvironment()
-                .getTimeOfDay();
-            int day = this.apiEnvironment.getComputerEnvironment()
-                .getDay();
+            double previousTime = time;
+            int previousDay = day;
+            double time = apiEnvironment.getComputerEnvironment().getTimeOfDay();
+            int day = apiEnvironment.getComputerEnvironment().getDay();
 
             if( time > previousTime || day > previousDay )
             {
-                double now = this.m_day * 24.0 + this.m_time;
-                Iterator<Int2ObjectMap.Entry<Alarm>> it = this.m_alarms.int2ObjectEntrySet()
-                    .iterator();
+                double now = this.day * 24.0 + this.time;
+                Iterator<Int2ObjectMap.Entry<Alarm>> it = alarms.int2ObjectEntrySet().iterator();
                 while( it.hasNext() )
                 {
                     Int2ObjectMap.Entry<Alarm> entry = it.next();
                     Alarm alarm = entry.getValue();
-                    double t = alarm.m_day * 24.0 + alarm.m_time;
+                    double t = alarm.day * 24.0 + alarm.time;
                     if( now >= t )
                     {
-                        this.apiEnvironment.queueEvent( "alarm", entry.getIntKey() );
+                        apiEnvironment.queueEvent( "alarm", entry.getIntKey() );
                         it.remove();
                     }
                 }
             }
 
-            this.m_time = time;
-            this.m_day = day;
+            this.time = time;
+            this.day = day;
         }
     }
 
     @Override
     public void shutdown()
     {
-        synchronized( this.m_alarms )
+        synchronized( alarms )
         {
-            this.m_alarms.clear();
-        }
-    }
-
-    /**
-     * Adds an event to the event queue. This event can later be pulled with os.pullEvent.
-     *
-     * @param name The name of the event to queue.
-     * @param args The parameters of the event.
-     * @cc.tparam string name The name of the event to queue.
-     * @cc.param ... The parameters of the event.
-     * @cc.see os.pullEvent To pull the event queued
-     */
-    @LuaFunction
-    public final void queueEvent( String name, IArguments args )
-    {
-        this.apiEnvironment.queueEvent( name,
-            args.drop( 1 )
-                .getAll() );
-    }
-
-    /**
-     * Starts a timer that will run for the specified number of seconds. Once the timer fires, a timer event will be added to the queue with the ID returned
-     * from this function as the first parameter.
-     *
-     * @param timer The number of seconds until the timer fires.
-     * @return The ID of the new timer.
-     * @throws LuaException If the time is below zero.
-     */
-    @LuaFunction
-    public final int startTimer( double timer ) throws LuaException
-    {
-        return this.apiEnvironment.startTimer( Math.round( checkFinite( 0, timer ) / 0.05 ) );
-    }
-
-    /**
-     * Cancels a timer previously started with startTimer. This will stop the timer from firing.
-     *
-     * @param token The ID of the timer to cancel.
-     * @see #startTimer To start a timer.
-     */
-    @LuaFunction
-    public final void cancelTimer( int token )
-    {
-        this.apiEnvironment.cancelTimer( token );
-    }
-
-    /**
-     * Sets an alarm that will fire at the specified world time. When it fires, an alarm event will be added to the event queue.
-     *
-     * @param time The time at which to fire the alarm, in the range [0.0, 24.0).
-     * @return The ID of the alarm that was set.
-     * @throws LuaException If the time is out of range.
-     */
-    @LuaFunction
-    public final int setAlarm( double time ) throws LuaException
-    {
-        checkFinite( 0, time );
-        if( time < 0.0 || time >= 24.0 )
-        {
-            throw new LuaException( "Number out of range" );
-        }
-        synchronized( this.m_alarms )
-        {
-            int day = time > this.m_time ? this.m_day : this.m_day + 1;
-            this.m_alarms.put( this.m_nextAlarmToken, new Alarm( time, day ) );
-            return this.m_nextAlarmToken++;
-        }
-    }
-
-    /**
-     * Cancels an alarm previously started with setAlarm. This will stop the alarm from firing.
-     *
-     * @param token The ID of the alarm to cancel.
-     * @see #setAlarm To set an alarm.
-     */
-    @LuaFunction
-    public final void cancelAlarm( int token )
-    {
-        synchronized( this.m_alarms )
-        {
-            this.m_alarms.remove( token );
-        }
-    }
-
-    /**
-     * Shuts down the computer immediately.
-     */
-    @LuaFunction( "shutdown" )
-    public final void doShutdown()
-    {
-        this.apiEnvironment.shutdown();
-    }
-
-    /**
-     * Reboots the computer immediately.
-     */
-    @LuaFunction( "reboot" )
-    public final void doReboot()
-    {
-        this.apiEnvironment.reboot();
-    }
-
-    /**
-     * Returns the ID of the computer.
-     *
-     * @return The ID of the computer.
-     */
-    @LuaFunction( {
-        "getComputerID",
-        "computerID"
-    } )
-    public final int getComputerID()
-    {
-        return this.apiEnvironment.getComputerID();
-    }
-
-    /**
-     * Returns the label of the computer, or {@code nil} if none is set.
-     *
-     * @return The label of the computer.
-     * @cc.treturn string The label of the computer.
-     */
-    @LuaFunction( {
-        "getComputerLabel",
-        "computerLabel"
-    } )
-    public final Object[] getComputerLabel()
-    {
-        String label = this.apiEnvironment.getLabel();
-        return label == null ? null : new Object[] { label };
-    }
-
-    /**
-     * Set the label of this computer.
-     *
-     * @param label The new label. May be {@code nil} in order to clear it.
-     */
-    @LuaFunction
-    public final void setComputerLabel( Optional<String> label )
-    {
-        this.apiEnvironment.setLabel( StringUtil.normaliseLabel( label.orElse( null ) ) );
-    }
-
-    /**
-     * Returns the number of seconds that the computer has been running.
-     *
-     * @return The computer's uptime.
-     */
-    @LuaFunction
-    public final double clock()
-    {
-        return this.m_clock * 0.05;
-    }
-
-    /**
-     * Returns the current time depending on the string passed in. This will always be in the range [0.0, 24.0).
-     *
-     * * If called with {@code ingame}, the current world time will be returned. This is the default if nothing is passed. * If called with {@code utc},
-     * returns the hour of the day in UTC time. * If called with {@code local}, returns the hour of the day in the timezone the server is located in.
-     *
-     * This function can also be called with a table returned from {@link #date}, which will convert the date fields into a UNIX timestamp (number of
-     * seconds since 1 January 1970).
-     *
-     * @param args The locale of the time, or a table filled by {@code os.date("*t")} to decode. Defaults to {@code ingame} locale if not specified.
-     * @return The hour of the selected locale, or a UNIX timestamp from the table, depending on the argument passed in.
-     * @throws LuaException If an invalid locale is passed.
-     * @cc.tparam [opt] string|table locale The locale of the time, or a table filled by {@code os.date("*t")} to decode. Defaults to {@code ingame}
-     * locale if not specified.
-     * @see #date To get a date table that can be converted with this function.
-     */
-    @LuaFunction
-    public final Object time( IArguments args ) throws LuaException
-    {
-        Object value = args.get( 0 );
-        if( value instanceof Map )
-        {
-            return LuaDateTime.fromTable( (Map<?, ?>) value );
-        }
-
-        String param = args.optString( 0, "ingame" );
-        switch( param.toLowerCase( Locale.ROOT ) )
-        {
-            case "utc": // Get Hour of day (UTC)
-                return getTimeForCalendar( Calendar.getInstance( TimeZone.getTimeZone( "UTC" ) ) );
-            case "local": // Get Hour of day (local time)
-                return getTimeForCalendar( Calendar.getInstance() );
-            case "ingame": // Get in-game hour
-                return this.m_time;
-            default:
-                throw new LuaException( "Unsupported operation" );
+            alarms.clear();
         }
     }
 
@@ -311,34 +135,6 @@ public class OSAPI implements ILuaAPI
         return time;
     }
 
-    /**
-     * Returns the day depending on the locale specified.
-     *
-     * * If called with {@code ingame}, returns the number of days since the world was created. This is the default. * If called with {@code utc}, returns
-     * the number of days since 1 January 1970 in the UTC timezone. * If called with {@code local}, returns the number of days since 1 January 1970 in the
-     * server's local timezone.
-     *
-     * @param args The locale to get the day for. Defaults to {@code ingame} if not set.
-     * @return The day depending on the selected locale.
-     * @throws LuaException If an invalid locale is passed.
-     */
-    @LuaFunction
-    public final int day( Optional<String> args ) throws LuaException
-    {
-        switch( args.orElse( "ingame" )
-            .toLowerCase( Locale.ROOT ) )
-        {
-            case "utc":     // Get numbers of days since 1970-01-01 (utc)
-                return getDayForCalendar( Calendar.getInstance( TimeZone.getTimeZone( "UTC" ) ) );
-            case "local": // Get numbers of days since 1970-01-01 (local time)
-                return getDayForCalendar( Calendar.getInstance() );
-            case "ingame":// Get game day
-                return this.m_day;
-            default:
-                throw new LuaException( "Unsupported operation" );
-        }
-    }
-
     private static int getDayForCalendar( Calendar c )
     {
         GregorianCalendar g = c instanceof GregorianCalendar ? (GregorianCalendar) c : new GregorianCalendar();
@@ -352,12 +148,244 @@ public class OSAPI implements ILuaAPI
         return day;
     }
 
+    private static long getEpochForCalendar( Calendar c )
+    {
+        return c.getTime().getTime();
+    }
+
+    /**
+     * Adds an event to the event queue. This event can later be pulled with
+     * os.pullEvent.
+     *
+     * @param name The name of the event to queue.
+     * @param args The parameters of the event.
+     * @cc.tparam string name The name of the event to queue.
+     * @cc.param ... The parameters of the event.
+     * @cc.see os.pullEvent To pull the event queued
+     */
+    @LuaFunction
+    public final void queueEvent( String name, IArguments args )
+    {
+        apiEnvironment.queueEvent( name, args.drop( 1 ).getAll() );
+    }
+
+    /**
+     * Starts a timer that will run for the specified number of seconds. Once
+     * the timer fires, a {@code timer} event will be added to the queue with
+     * the ID returned from this function as the first parameter.
+     *
+     * As with @{os.sleep|sleep}, {@code timer} will automatically be rounded up
+     * to the nearest multiple of 0.05 seconds, as it waits for a fixed amount
+     * of world ticks.
+     *
+     * @param timer The number of seconds until the timer fires.
+     * @return The ID of the new timer. This can be used to filter the
+     * {@code timer} event, or {@link #cancelTimer cancel the timer}.
+     * @throws LuaException If the time is below zero.
+     * @see #cancelTimer To cancel a timer.
+     */
+    @LuaFunction
+    public final int startTimer( double timer ) throws LuaException
+    {
+        return apiEnvironment.startTimer( Math.round( checkFinite( 0, timer ) / 0.05 ) );
+    }
+
+    /**
+     * Cancels a timer previously started with startTimer. This will stop the
+     * timer from firing.
+     *
+     * @param token The ID of the timer to cancel.
+     * @see #startTimer To start a timer.
+     */
+    @LuaFunction
+    public final void cancelTimer( int token )
+    {
+        apiEnvironment.cancelTimer( token );
+    }
+
+    /**
+     * Sets an alarm that will fire at the specified world time. When it fires,
+     * an {@code alarm} event will be added to the event queue with the ID
+     * returned from this function as the first parameter.
+     *
+     * @param time The time at which to fire the alarm, in the range [0.0, 24.0).
+     * @return The ID of the new alarm. This can be used to filter the
+     * {@code alarm} event, or {@link #cancelAlarm cancel the alarm}.
+     * @throws LuaException If the time is out of range.
+     * @see #cancelAlarm To cancel an alarm.
+     */
+    @LuaFunction
+    public final int setAlarm( double time ) throws LuaException
+    {
+        checkFinite( 0, time );
+        if( time < 0.0 || time >= 24.0 ) throw new LuaException( "Number out of range" );
+        synchronized( alarms )
+        {
+            int day = time > this.time ? this.day : this.day + 1;
+            alarms.put( nextAlarmToken, new Alarm( time, day ) );
+            return nextAlarmToken++;
+        }
+    }
+
+    /**
+     * Cancels an alarm previously started with setAlarm. This will stop the
+     * alarm from firing.
+     *
+     * @param token The ID of the alarm to cancel.
+     * @see #setAlarm To set an alarm.
+     */
+    @LuaFunction
+    public final void cancelAlarm( int token )
+    {
+        synchronized( alarms )
+        {
+            alarms.remove( token );
+        }
+    }
+
+    /**
+     * Shuts down the computer immediately.
+     */
+    @LuaFunction( "shutdown" )
+    public final void doShutdown()
+    {
+        apiEnvironment.shutdown();
+    }
+
+    /**
+     * Reboots the computer immediately.
+     */
+    @LuaFunction( "reboot" )
+    public final void doReboot()
+    {
+        apiEnvironment.reboot();
+    }
+
+    /**
+     * Returns the ID of the computer.
+     *
+     * @return The ID of the computer.
+     */
+    @LuaFunction( { "getComputerID", "computerID" } )
+    public final int getComputerID()
+    {
+        return apiEnvironment.getComputerID();
+    }
+
+    /**
+     * Returns the label of the computer, or {@code nil} if none is set.
+     *
+     * @return The label of the computer.
+     * @cc.treturn string The label of the computer.
+     */
+    @LuaFunction( { "getComputerLabel", "computerLabel" } )
+    public final Object[] getComputerLabel()
+    {
+        String label = apiEnvironment.getLabel();
+        return label == null ? null : new Object[] { label };
+    }
+
+    /**
+     * Set the label of this computer.
+     *
+     * @param label The new label. May be {@code nil} in order to clear it.
+     */
+    @LuaFunction
+    public final void setComputerLabel( Optional<String> label )
+    {
+        apiEnvironment.setLabel( StringUtil.normaliseLabel( label.orElse( null ) ) );
+    }
+
+    /**
+     * Returns the number of seconds that the computer has been running.
+     *
+     * @return The computer's uptime.
+     */
+    @LuaFunction
+    public final double clock()
+    {
+        return clock * 0.05;
+    }
+
+    /**
+     * Returns the current time depending on the string passed in. This will
+     * always be in the range [0.0, 24.0).
+     *
+     * * If called with {@code ingame}, the current world time will be returned.
+     * This is the default if nothing is passed.
+     * * If called with {@code utc}, returns the hour of the day in UTC time.
+     * * If called with {@code local}, returns the hour of the day in the
+     * timezone the server is located in.
+     *
+     * This function can also be called with a table returned from {@link #date},
+     * which will convert the date fields into a UNIX timestamp (number of
+     * seconds since 1 January 1970).
+     *
+     * @param args The locale of the time, or a table filled by {@code os.date("*t")} to decode. Defaults to {@code ingame} locale if not specified.
+     * @return The hour of the selected locale, or a UNIX timestamp from the table, depending on the argument passed in.
+     * @throws LuaException If an invalid locale is passed.
+     * @cc.tparam [opt] string|table locale The locale of the time, or a table filled by {@code os.date("*t")} to decode. Defaults to {@code ingame} locale if not specified.
+     * @see #date To get a date table that can be converted with this function.
+     */
+    @LuaFunction
+    public final Object time( IArguments args ) throws LuaException
+    {
+        Object value = args.get( 0 );
+        if( value instanceof Map ) return LuaDateTime.fromTable( (Map<?, ?>) value );
+
+        String param = args.optString( 0, "ingame" );
+        switch( param.toLowerCase( Locale.ROOT ) )
+        {
+            case "utc": // Get Hour of day (UTC)
+                return getTimeForCalendar( Calendar.getInstance( TimeZone.getTimeZone( "UTC" ) ) );
+            case "local": // Get Hour of day (local time)
+                return getTimeForCalendar( Calendar.getInstance() );
+            case "ingame": // Get in-game hour
+                return time;
+            default:
+                throw new LuaException( "Unsupported operation" );
+        }
+    }
+
+    /**
+     * Returns the day depending on the locale specified.
+     *
+     * * If called with {@code ingame}, returns the number of days since the
+     * world was created. This is the default.
+     * * If called with {@code utc}, returns the number of days since 1 January
+     * 1970 in the UTC timezone.
+     * * If called with {@code local}, returns the number of days since 1
+     * January 1970 in the server's local timezone.
+     *
+     * @param args The locale to get the day for. Defaults to {@code ingame} if not set.
+     * @return The day depending on the selected locale.
+     * @throws LuaException If an invalid locale is passed.
+     */
+    @LuaFunction
+    public final int day( Optional<String> args ) throws LuaException
+    {
+        switch( args.orElse( "ingame" ).toLowerCase( Locale.ROOT ) )
+        {
+            case "utc":     // Get numbers of days since 1970-01-01 (utc)
+                return getDayForCalendar( Calendar.getInstance( TimeZone.getTimeZone( "UTC" ) ) );
+            case "local": // Get numbers of days since 1970-01-01 (local time)
+                return getDayForCalendar( Calendar.getInstance() );
+            case "ingame":// Get game day
+                return day;
+            default:
+                throw new LuaException( "Unsupported operation" );
+        }
+    }
+
     /**
      * Returns the number of milliseconds since an epoch depending on the locale.
      *
-     * * If called with {@code ingame}, returns the number of milliseconds since the world was created. This is the default. * If called with {@code utc},
-     * returns the number of milliseconds since 1 January 1970 in the UTC timezone. * If called with {@code local}, returns the number of seconds since 1 January
-     * 1970 in the server's local timezone.
+     * * If called with {@code ingame}, returns the number of milliseconds since the
+     * world was created. This is the default.
+     * * If called with {@code utc}, returns the number of milliseconds since 1
+     * January 1970 in the UTC timezone.
+     * * If called with {@code local}, returns the number of milliseconds since 1
+     * January 1970 in the server's local timezone.
      *
      * @param args The locale to get the milliseconds for. Defaults to {@code ingame} if not set.
      * @return The milliseconds since the epoch depending on the selected locale.
@@ -366,8 +394,7 @@ public class OSAPI implements ILuaAPI
     @LuaFunction
     public final long epoch( Optional<String> args ) throws LuaException
     {
-        switch( args.orElse( "ingame" )
-            .toLowerCase( Locale.ROOT ) )
+        switch( args.orElse( "ingame" ).toLowerCase( Locale.ROOT ) )
         {
             case "utc":
             {
@@ -383,30 +410,29 @@ public class OSAPI implements ILuaAPI
             }
             case "ingame":
                 // Get in-game epoch
-                synchronized( this.m_alarms )
+                synchronized( alarms )
                 {
-                    return this.m_day * 86400000L + (long) (this.m_time * 3600000.0);
+                    return day * 86400000L + (long) (time * 3600000.0);
                 }
             default:
                 throw new LuaException( "Unsupported operation" );
         }
     }
 
-    private static long getEpochForCalendar( Calendar c )
-    {
-        return c.getTime()
-            .getTime();
-    }
-
     /**
-     * Returns a date string (or table) using a specified format string and optional time to format.
+     * Returns a date string (or table) using a specified format string and
+     * optional time to format.
      *
-     * The format string takes the same formats as C's {@code strftime} function (http://www.cplusplus.com/reference/ctime/strftime/). In extension, it can
-     * be prefixed with an exclamation mark ({@code !}) to use UTC time instead of the server's local timezone.
+     * The format string takes the same formats as C's {@code strftime} function
+     * (http://www.cplusplus.com/reference/ctime/strftime/). In extension, it
+     * can be prefixed with an exclamation mark ({@code !}) to use UTC time
+     * instead of the server's local timezone.
      *
-     * If the format is exactly {@code *t} (optionally prefixed with {@code !}), a table will be returned instead. This table has fields for the year,
-     * month, day, hour, minute, second, day of the week, day of the year, and whether Daylight Savings Time is in effect. This table can be converted to a
-     * UNIX timestamp (days since 1 January 1970) with {@link #date}.
+     * If the format is exactly {@code *t} (optionally prefixed with {@code !}), a
+     * table will be returned instead. This table has fields for the year, month,
+     * day, hour, minute, second, day of the week, day of the year, and whether
+     * Daylight Savings Time is in effect. This table can be converted to a UNIX
+     * timestamp (days since 1 January 1970) with {@link #date}.
      *
      * @param formatA The format of the string to return. This defaults to {@code %c}, which expands to a string similar to "Sat Dec 24 16:58:00 2011".
      * @param timeA   The time to convert to a string. This defaults to the current time.
@@ -417,8 +443,7 @@ public class OSAPI implements ILuaAPI
     public final Object date( Optional<String> formatA, Optional<Long> timeA ) throws LuaException
     {
         String format = formatA.orElse( "%c" );
-        long time = timeA.orElseGet( () -> Instant.now()
-            .getEpochSecond() );
+        long time = timeA.orElseGet( () -> Instant.now().getEpochSecond() );
 
         Instant instant = Instant.ofEpochSecond( time );
         ZonedDateTime date;
@@ -432,40 +457,15 @@ public class OSAPI implements ILuaAPI
         else
         {
             ZoneId id = ZoneId.systemDefault();
-            offset = id.getRules()
-                .getOffset( instant );
+            offset = id.getRules().getOffset( instant );
             date = ZonedDateTime.ofInstant( instant, id );
         }
 
-        if( format.equals( "*t" ) )
-        {
-            return LuaDateTime.toTable( date, offset, instant );
-        }
+        if( format.equals( "*t" ) ) return LuaDateTime.toTable( date, offset, instant );
 
         DateTimeFormatterBuilder formatter = new DateTimeFormatterBuilder();
         LuaDateTime.format( formatter, format, offset );
-        return formatter.toFormatter( Locale.ROOT )
-            .format( date );
-    }
-
-    private static class Alarm implements Comparable<Alarm>
-    {
-        final double m_time;
-        final int m_day;
-
-        Alarm( double time, int day )
-        {
-            this.m_time = time;
-            this.m_day = day;
-        }
-
-        @Override
-        public int compareTo( @Nonnull Alarm o )
-        {
-            double t = this.m_day * 24.0 + this.m_time;
-            double ot = this.m_day * 24.0 + this.m_time;
-            return Double.compare( t, ot );
-        }
+        return formatter.toFormatter( Locale.ROOT ).format( date );
     }
 
 }

src/main/java/dan200/computercraft/core/apis/PeripheralAPI.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.filesystem.IMount;
@@ -31,213 +30,6 @@ import java.util.*;
  */
 public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChangeListener
 {
-    private final IAPIEnvironment environment;
-    private final PeripheralWrapper[] peripherals = new PeripheralWrapper[6];
-    private boolean running;
-
-    public PeripheralAPI( IAPIEnvironment environment )
-    {
-        this.environment = environment;
-        this.environment.setPeripheralChangeListener( this );
-        this.running = false;
-    }
-
-    public static Map<String, PeripheralMethod> getMethods( IPeripheral peripheral )
-    {
-        String[] dynamicMethods = peripheral instanceof IDynamicPeripheral ? Objects.requireNonNull( ((IDynamicPeripheral) peripheral).getMethodNames(),
-            "Peripheral methods cannot be null" ) :
-            LuaMethod.EMPTY_METHODS;
-
-        List<NamedMethod<PeripheralMethod>> methods = PeripheralMethod.GENERATOR.getMethods( peripheral.getClass() );
-
-        Map<String, PeripheralMethod> methodMap = new HashMap<>( methods.size() + dynamicMethods.length );
-        for( int i = 0; i < dynamicMethods.length; i++ )
-        {
-            methodMap.put( dynamicMethods[i], PeripheralMethod.DYNAMIC.get( i ) );
-        }
-        for( NamedMethod<PeripheralMethod> method : methods )
-        {
-            methodMap.put( method.getName(), method.getMethod() );
-        }
-        return methodMap;
-    }
-
-    // IPeripheralChangeListener
-
-    @Override
-    public void onPeripheralChanged( ComputerSide side, IPeripheral newPeripheral )
-    {
-        synchronized( this.peripherals )
-        {
-            int index = side.ordinal();
-            if( this.peripherals[index] != null )
-            {
-                // Queue a detachment
-                final PeripheralWrapper wrapper = this.peripherals[index];
-                if( wrapper.isAttached() )
-                {
-                    wrapper.detach();
-                }
-
-                // Queue a detachment event
-                this.environment.queueEvent( "peripheral_detach", side.getName() );
-            }
-
-            // Assign the new peripheral
-            this.peripherals[index] = newPeripheral == null ? null : new PeripheralWrapper( newPeripheral, side.getName() );
-
-            if( this.peripherals[index] != null )
-            {
-                // Queue an attachment
-                final PeripheralWrapper wrapper = this.peripherals[index];
-                if( this.running && !wrapper.isAttached() )
-                {
-                    wrapper.attach();
-                }
-
-                // Queue an attachment event
-                this.environment.queueEvent( "peripheral", side.getName() );
-            }
-        }
-    }
-
-    @Override
-    public String[] getNames()
-    {
-        return new String[] { "peripheral" };
-    }
-
-    @Override
-    public void startup()
-    {
-        synchronized( this.peripherals )
-        {
-            this.running = true;
-            for( int i = 0; i < 6; i++ )
-            {
-                PeripheralWrapper wrapper = this.peripherals[i];
-                if( wrapper != null && !wrapper.isAttached() )
-                {
-                    wrapper.attach();
-                }
-            }
-        }
-    }
-
-    @Override
-    public void shutdown()
-    {
-        synchronized( this.peripherals )
-        {
-            this.running = false;
-            for( int i = 0; i < 6; i++ )
-            {
-                PeripheralWrapper wrapper = this.peripherals[i];
-                if( wrapper != null && wrapper.isAttached() )
-                {
-                    wrapper.detach();
-                }
-            }
-        }
-    }
-
-    @LuaFunction
-    public final boolean isPresent( String sideName )
-    {
-        ComputerSide side = ComputerSide.valueOfInsensitive( sideName );
-        if( side != null )
-        {
-            synchronized( this.peripherals )
-            {
-                PeripheralWrapper p = this.peripherals[side.ordinal()];
-                if( p != null )
-                {
-                    return true;
-                }
-            }
-        }
-        return false;
-    }
-
-    @LuaFunction
-    public final Object[] getType( String sideName )
-    {
-        ComputerSide side = ComputerSide.valueOfInsensitive( sideName );
-        if( side == null )
-        {
-            return null;
-        }
-
-        synchronized( this.peripherals )
-        {
-            PeripheralWrapper p = this.peripherals[side.ordinal()];
-            if( p != null )
-            {
-                return new Object[] { p.getType() };
-            }
-        }
-        return null;
-    }
-
-    @LuaFunction
-    public final Object[] getMethods( String sideName )
-    {
-        ComputerSide side = ComputerSide.valueOfInsensitive( sideName );
-        if( side == null )
-        {
-            return null;
-        }
-
-        synchronized( this.peripherals )
-        {
-            PeripheralWrapper p = this.peripherals[side.ordinal()];
-            if( p != null )
-            {
-                return new Object[] { p.getMethods() };
-            }
-        }
-        return null;
-    }
-
-    @LuaFunction
-    public final MethodResult call( ILuaContext context, IArguments args ) throws LuaException
-    {
-        ComputerSide side = ComputerSide.valueOfInsensitive( args.getString( 0 ) );
-        String methodName = args.getString( 1 );
-        IArguments methodArgs = args.drop( 2 );
-
-        if( side == null )
-        {
-            throw new LuaException( "No peripheral attached" );
-        }
-
-        PeripheralWrapper p;
-        synchronized( this.peripherals )
-        {
-            p = this.peripherals[side.ordinal()];
-        }
-        if( p == null )
-        {
-            throw new LuaException( "No peripheral attached" );
-        }
-
-        try
-        {
-            return p.call( context, methodName, methodArgs )
-                .adjustError( 1 );
-        }
-        catch( LuaException e )
-        {
-            // We increase the error level by one in order to shift the error level to where peripheral.call was
-            // invoked. It would be possible to do it in Lua code, but would add significantly more overhead.
-            if( e.getLevel() > 0 )
-            {
-                throw new FastLuaException( e.getMessage(), e.getLevel() + 1 );
-            }
-            throw e;
-        }
-    }
-
     private class PeripheralWrapper extends ComputerAccess
     {
         private final String side;
@@ -249,54 +41,54 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
 
         PeripheralWrapper( IPeripheral peripheral, String side )
         {
-            super( PeripheralAPI.this.environment );
+            super( environment );
             this.side = side;
             this.peripheral = peripheral;
-            this.attached = false;
+            attached = false;
 
-            this.type = Objects.requireNonNull( peripheral.getType(), "Peripheral type cannot be null" );
+            type = Objects.requireNonNull( peripheral.getType(), "Peripheral type cannot be null" );
 
-            this.methodMap = PeripheralAPI.getMethods( peripheral );
-        }
-
-        public String getType()
-        {
-            return this.type;
+            methodMap = PeripheralAPI.getMethods( peripheral );
         }
 
         public IPeripheral getPeripheral()
         {
-            return this.peripheral;
+            return peripheral;
+        }
+
+        public String getType()
+        {
+            return type;
         }
 
         public Collection<String> getMethods()
         {
-            return this.methodMap.keySet();
+            return methodMap.keySet();
+        }
+
+        public synchronized boolean isAttached()
+        {
+            return attached;
         }
 
         public synchronized void attach()
         {
-            this.attached = true;
-            this.peripheral.attach( this );
+            attached = true;
+            peripheral.attach( this );
         }
 
         public void detach()
         {
             // Call detach
-            this.peripheral.detach( this );
+            peripheral.detach( this );
 
             synchronized( this )
             {
                 // Unmount everything the detach function forgot to do
-                this.unmountAll();
+                unmountAll();
             }
 
-            this.attached = false;
-        }
-
-        public synchronized boolean isAttached()
-        {
-            return this.attached;
+            attached = false;
         }
 
         public MethodResult call( ILuaContext context, String methodName, IArguments arguments ) throws LuaException
@@ -304,100 +96,64 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             PeripheralMethod method;
             synchronized( this )
             {
-                method = this.methodMap.get( methodName );
+                method = methodMap.get( methodName );
             }
 
-            if( method == null )
-            {
-                throw new LuaException( "No such method " + methodName );
-            }
+            if( method == null ) throw new LuaException( "No such method " + methodName );
 
-            PeripheralAPI.this.environment.addTrackingChange( TrackingField.PERIPHERAL_OPS );
-            return method.apply( this.peripheral, context, this, arguments );
+            environment.addTrackingChange( TrackingField.PERIPHERAL_OPS );
+            return method.apply( peripheral, context, this, arguments );
         }
 
         // IComputerAccess implementation
         @Override
         public synchronized String mount( @Nonnull String desiredLoc, @Nonnull IMount mount, @Nonnull String driveName )
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
             return super.mount( desiredLoc, mount, driveName );
         }
 
         @Override
         public synchronized String mountWritable( @Nonnull String desiredLoc, @Nonnull IWritableMount mount, @Nonnull String driveName )
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
             return super.mountWritable( desiredLoc, mount, driveName );
         }
 
         @Override
         public synchronized void unmount( String location )
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
             super.unmount( location );
         }
 
         @Override
         public int getID()
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
             return super.getID();
         }
 
         @Override
         public void queueEvent( @Nonnull String event, Object... arguments )
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
             super.queueEvent( event, arguments );
         }
 
-        @Nonnull
-        @Override
-        public IWorkMonitor getMainThreadMonitor()
-        {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
-            return super.getMainThreadMonitor();
-        }
-
-
         @Nonnull
         @Override
         public String getAttachmentName()
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
-            return this.side;
+            if( !attached ) throw new NotAttachedException();
+            return side;
         }
 
         @Nonnull
         @Override
         public Map<String, IPeripheral> getAvailablePeripherals()
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
 
             Map<String, IPeripheral> peripherals = new HashMap<>();
             for( PeripheralWrapper wrapper : PeripheralAPI.this.peripherals )
@@ -415,15 +171,11 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
         @Override
         public IPeripheral getAvailablePeripheral( @Nonnull String name )
         {
-            if( !this.attached )
-            {
-                throw new NotAttachedException();
-            }
+            if( !attached ) throw new NotAttachedException();
 
-            for( PeripheralWrapper wrapper : PeripheralAPI.this.peripherals )
+            for( PeripheralWrapper wrapper : peripherals )
             {
-                if( wrapper != null && wrapper.isAttached() && wrapper.getAttachmentName()
-                    .equals( name ) )
+                if( wrapper != null && wrapper.isAttached() && wrapper.getAttachmentName().equals( name ) )
                 {
                     return wrapper.getPeripheral();
                 }
@@ -431,6 +183,186 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             return null;
         }
 
+        @Nonnull
+        @Override
+        public IWorkMonitor getMainThreadMonitor()
+        {
+            if( !attached ) throw new NotAttachedException();
+            return super.getMainThreadMonitor();
+        }
+    }
 
+    private final IAPIEnvironment environment;
+    private final PeripheralWrapper[] peripherals = new PeripheralWrapper[6];
+    private boolean running;
+
+    public PeripheralAPI( IAPIEnvironment environment )
+    {
+        this.environment = environment;
+        this.environment.setPeripheralChangeListener( this );
+        running = false;
+    }
+
+    // IPeripheralChangeListener
+
+    @Override
+    public void onPeripheralChanged( ComputerSide side, IPeripheral newPeripheral )
+    {
+        synchronized( peripherals )
+        {
+            int index = side.ordinal();
+            if( peripherals[index] != null )
+            {
+                // Queue a detachment
+                final PeripheralWrapper wrapper = peripherals[index];
+                if( wrapper.isAttached() ) wrapper.detach();
+
+                // Queue a detachment event
+                environment.queueEvent( "peripheral_detach", side.getName() );
+            }
+
+            // Assign the new peripheral
+            peripherals[index] = newPeripheral == null ? null
+                : new PeripheralWrapper( newPeripheral, side.getName() );
+
+            if( peripherals[index] != null )
+            {
+                // Queue an attachment
+                final PeripheralWrapper wrapper = peripherals[index];
+                if( running && !wrapper.isAttached() ) wrapper.attach();
+
+                // Queue an attachment event
+                environment.queueEvent( "peripheral", side.getName() );
+            }
+        }
+    }
+
+    @Override
+    public String[] getNames()
+    {
+        return new String[] { "peripheral" };
+    }
+
+    @Override
+    public void startup()
+    {
+        synchronized( peripherals )
+        {
+            running = true;
+            for( int i = 0; i < 6; i++ )
+            {
+                PeripheralWrapper wrapper = peripherals[i];
+                if( wrapper != null && !wrapper.isAttached() ) wrapper.attach();
+            }
+        }
+    }
+
+    @Override
+    public void shutdown()
+    {
+        synchronized( peripherals )
+        {
+            running = false;
+            for( int i = 0; i < 6; i++ )
+            {
+                PeripheralWrapper wrapper = peripherals[i];
+                if( wrapper != null && wrapper.isAttached() )
+                {
+                    wrapper.detach();
+                }
+            }
+        }
+    }
+
+    @LuaFunction
+    public final boolean isPresent( String sideName )
+    {
+        ComputerSide side = ComputerSide.valueOfInsensitive( sideName );
+        if( side != null )
+        {
+            synchronized( peripherals )
+            {
+                PeripheralWrapper p = peripherals[side.ordinal()];
+                if( p != null ) return true;
+            }
+        }
+        return false;
+    }
+
+    @LuaFunction
+    public final Object[] getType( String sideName )
+    {
+        ComputerSide side = ComputerSide.valueOfInsensitive( sideName );
+        if( side == null ) return null;
+
+        synchronized( peripherals )
+        {
+            PeripheralWrapper p = peripherals[side.ordinal()];
+            if( p != null ) return new Object[] { p.getType() };
+        }
+        return null;
+    }
+
+    @LuaFunction
+    public final Object[] getMethods( String sideName )
+    {
+        ComputerSide side = ComputerSide.valueOfInsensitive( sideName );
+        if( side == null ) return null;
+
+        synchronized( peripherals )
+        {
+            PeripheralWrapper p = peripherals[side.ordinal()];
+            if( p != null ) return new Object[] { p.getMethods() };
+        }
+        return null;
+    }
+
+    @LuaFunction
+    public final MethodResult call( ILuaContext context, IArguments args ) throws LuaException
+    {
+        ComputerSide side = ComputerSide.valueOfInsensitive( args.getString( 0 ) );
+        String methodName = args.getString( 1 );
+        IArguments methodArgs = args.drop( 2 );
+
+        if( side == null ) throw new LuaException( "No peripheral attached" );
+
+        PeripheralWrapper p;
+        synchronized( peripherals )
+        {
+            p = peripherals[side.ordinal()];
+        }
+        if( p == null ) throw new LuaException( "No peripheral attached" );
+
+        try
+        {
+            return p.call( context, methodName, methodArgs ).adjustError( 1 );
+        }
+        catch( LuaException e )
+        {
+            // We increase the error level by one in order to shift the error level to where peripheral.call was
+            // invoked. It would be possible to do it in Lua code, but would add significantly more overhead.
+            if( e.getLevel() > 0 ) throw new FastLuaException( e.getMessage(), e.getLevel() + 1 );
+            throw e;
+        }
+    }
+
+    public static Map<String, PeripheralMethod> getMethods( IPeripheral peripheral )
+    {
+        String[] dynamicMethods = peripheral instanceof IDynamicPeripheral
+            ? Objects.requireNonNull( ((IDynamicPeripheral) peripheral).getMethodNames(), "Peripheral methods cannot be null" )
+            : LuaMethod.EMPTY_METHODS;
+
+        List<NamedMethod<PeripheralMethod>> methods = PeripheralMethod.GENERATOR.getMethods( peripheral.getClass() );
+
+        Map<String, PeripheralMethod> methodMap = new HashMap<>( methods.size() + dynamicMethods.length );
+        for( int i = 0; i < dynamicMethods.length; i++ )
+        {
+            methodMap.put( dynamicMethods[i], PeripheralMethod.DYNAMIC.get( i ) );
+        }
+        for( NamedMethod<PeripheralMethod> method : methods )
+        {
+            methodMap.put( method.getName(), method.getMethod() );
+        }
+        return methodMap;
     }
 }

src/main/java/dan200/computercraft/core/apis/RedstoneAPI.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.ILuaAPI;
@@ -14,37 +13,43 @@ import dan200.computercraft.core.computer.ComputerSide;
 /**
  * Interact with redstone attached to this computer.
  *
- * The {@link RedstoneAPI} library exposes three "types" of redstone control: - Binary input/output ({@link #setOutput}/{@link #getInput}): These simply
- * check if a redstone wire has any input or output. A signal strength of 1 and 15 are treated the same. - Analogue input/output ({@link
- * #setAnalogOutput}/{@link #getAnalogInput}): These work with the actual signal strength of the redstone wired, from 0 to 15. - Bundled cables ({@link
- * #setBundledOutput}/{@link #getBundledInput}): These interact with "bundled" cables, such as those from Project:Red. These allow you to send 16 separate
- * on/off signals. Each channel corresponds to a colour, with the first being @{colors.white} and the last @{colors.black}.
+ * The {@link RedstoneAPI} library exposes three "types" of redstone control:
+ * - Binary input/output ({@link #setOutput}/{@link #getInput}): These simply check if a redstone wire has any input or
+ * output. A signal strength of 1 and 15 are treated the same.
+ * - Analogue input/output ({@link #setAnalogOutput}/{@link #getAnalogInput}): These work with the actual signal
+ * strength of the redstone wired, from 0 to 15.
+ * - Bundled cables ({@link #setBundledOutput}/{@link #getBundledInput}): These interact with "bundled" cables, such
+ * as those from Project:Red. These allow you to send 16 separate on/off signals. Each channel corresponds to a
+ * colour, with the first being @{colors.white} and the last @{colors.black}.
  *
- * Whenever a redstone input changes, a {@code redstone} event will be fired. This may be used instead of repeativly polling.
+ * Whenever a redstone input changes, a {@code redstone} event will be fired. This may be used instead of repeativly
+ * polling.
  *
- * This module may also be referred to as {@code rs}. For example, one may call {@code rs.getSides()} instead of {@link #getSides}.
+ * This module may also be referred to as {@code rs}. For example, one may call {@code rs.getSides()} instead of
+ * {@link #getSides}.
  *
  * @cc.usage Toggle the redstone signal above the computer every 0.5 seconds.
  *
  * <pre>
- *     while true do
- *       redstone.setOutput("top", not redstone.getOutput("top"))
- *       sleep(0.5)
- *     end
- *     </pre>
+ * while true do
+ *   redstone.setOutput("top", not redstone.getOutput("top"))
+ *   sleep(0.5)
+ * end
+ * </pre>
  * @cc.usage Mimic a redstone comparator in [subtraction mode][comparator].
  *
  * <pre>
- *     while true do
- *       local rear = rs.getAnalogueInput("back")
- *       local sides = math.max(rs.getAnalogueInput("left"), rs.getAnalogueInput("right"))
- *       rs.setAnalogueOutput("front", math.max(rear - sides, 0))
+ * while true do
+ *   local rear = rs.getAnalogueInput("back")
+ *   local sides = math.max(rs.getAnalogueInput("left"), rs.getAnalogueInput("right"))
+ *   rs.setAnalogueOutput("front", math.max(rear - sides, 0))
  *
- *       os.pullEvent("redstone") -- Wait for a change to inputs.
- *     end
- *     </pre>
+ *   os.pullEvent("redstone") -- Wait for a change to inputs.
+ * end
+ * </pre>
  *
- * [comparator]: https://minecraft.gamepedia.com/Redstone_Comparator#Subtract_signal_strength "Redstone Comparator on the Minecraft wiki."
+ * [comparator]: https://minecraft.gamepedia.com/Redstone_Comparator#Subtract_signal_strength "Redstone Comparator on
+ * the Minecraft wiki."
  * @cc.module redstone
  */
 public class RedstoneAPI implements ILuaAPI
@@ -59,14 +64,12 @@ public class RedstoneAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "rs",
-            "redstone"
-        };
+        return new String[] { "rs", "redstone" };
     }
 
     /**
-     * Returns a table containing the six sides of the computer. Namely, "top", "bottom", "left", "right", "front" and "back".
+     * Returns a table containing the six sides of the computer. Namely, "top", "bottom", "left", "right", "front" and
+     * "back".
      *
      * @return A table of valid sides.
      */
@@ -85,7 +88,7 @@ public class RedstoneAPI implements ILuaAPI
     @LuaFunction
     public final void setOutput( ComputerSide side, boolean on )
     {
-        this.environment.setOutput( side, on ? 15 : 0 );
+        environment.setOutput( side, on ? 15 : 0 );
     }
 
     /**
@@ -98,7 +101,7 @@ public class RedstoneAPI implements ILuaAPI
     @LuaFunction
     public final boolean getOutput( ComputerSide side )
     {
-        return this.environment.getOutput( side ) > 0;
+        return environment.getOutput( side ) > 0;
     }
 
     /**
@@ -110,7 +113,7 @@ public class RedstoneAPI implements ILuaAPI
     @LuaFunction
     public final boolean getInput( ComputerSide side )
     {
-        return this.environment.getInput( side ) > 0;
+        return environment.getInput( side ) > 0;
     }
 
     /**
@@ -120,17 +123,11 @@ public class RedstoneAPI implements ILuaAPI
      * @param value The signal strength between 0 and 15.
      * @throws LuaException If {@code value} is not betwene 0 and 15.
      */
-    @LuaFunction( {
-        "setAnalogOutput",
-        "setAnalogueOutput"
-    } )
+    @LuaFunction( { "setAnalogOutput", "setAnalogueOutput" } )
     public final void setAnalogOutput( ComputerSide side, int value ) throws LuaException
     {
-        if( value < 0 || value > 15 )
-        {
-            throw new LuaException( "Expected number in range 0-15" );
-        }
-        this.environment.setOutput( side, value );
+        if( value < 0 || value > 15 ) throw new LuaException( "Expected number in range 0-15" );
+        environment.setOutput( side, value );
     }
 
     /**
@@ -140,13 +137,10 @@ public class RedstoneAPI implements ILuaAPI
      * @return The output signal strength, between 0 and 15.
      * @see #setAnalogOutput
      */
-    @LuaFunction( {
-        "getAnalogOutput",
-        "getAnalogueOutput"
-    } )
+    @LuaFunction( { "getAnalogOutput", "getAnalogueOutput" } )
     public final int getAnalogOutput( ComputerSide side )
     {
-        return this.environment.getOutput( side );
+        return environment.getOutput( side );
     }
 
     /**
@@ -155,13 +149,10 @@ public class RedstoneAPI implements ILuaAPI
      * @param side The side to get.
      * @return The input signal strength, between 0 and 15.
      */
-    @LuaFunction( {
-        "getAnalogInput",
-        "getAnalogueInput"
-    } )
+    @LuaFunction( { "getAnalogInput", "getAnalogueInput" } )
     public final int getAnalogInput( ComputerSide side )
     {
-        return this.environment.getInput( side );
+        return environment.getInput( side );
     }
 
     /**
@@ -175,7 +166,7 @@ public class RedstoneAPI implements ILuaAPI
     @LuaFunction
     public final void setBundledOutput( ComputerSide side, int output )
     {
-        this.environment.setBundledOutput( side, output );
+        environment.setBundledOutput( side, output );
     }
 
     /**
@@ -187,7 +178,7 @@ public class RedstoneAPI implements ILuaAPI
     @LuaFunction
     public final int getBundledOutput( ComputerSide side )
     {
-        return this.environment.getBundledOutput( side );
+        return environment.getBundledOutput( side );
     }
 
     /**
@@ -211,14 +202,14 @@ public class RedstoneAPI implements ILuaAPI
      * @return If the colours are on.
      * @cc.usage Check if @{colors.white} and @{colors.black} are on above the computer.
      * <pre>
-     *     print(redstone.testBundledInput("top", colors.combine(colors.white, colors.black)))
-     *     </pre>
+     * print(redstone.testBundledInput("top", colors.combine(colors.white, colors.black)))
+     * </pre>
      * @see #getBundledInput
      */
     @LuaFunction
     public final boolean testBundledInput( ComputerSide side, int mask )
     {
-        int input = this.environment.getBundledInput( side );
+        int input = environment.getBundledInput( side );
         return (input & mask) == mask;
     }
 }

src/main/java/dan200/computercraft/core/apis/TableHelper.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.LuaException;
@@ -22,7 +21,32 @@ public final class TableHelper
 {
     private TableHelper()
     {
-        throw new IllegalStateException( "Cannot instantiate singleton " + this.getClass().getName() );
+        throw new IllegalStateException( "Cannot instantiate singleton " + getClass().getName() );
+    }
+
+    @Nonnull
+    public static LuaException badKey( @Nonnull String key, @Nonnull String expected, @Nullable Object actual )
+    {
+        return badKey( key, expected, LuaValues.getType( actual ) );
+    }
+
+    @Nonnull
+    public static LuaException badKey( @Nonnull String key, @Nonnull String expected, @Nonnull String actual )
+    {
+        return new LuaException( "bad field '" + key + "' (" + expected + " expected, got " + actual + ")" );
+    }
+
+    public static double getNumberField( @Nonnull Map<?, ?> table, @Nonnull String key ) throws LuaException
+    {
+        Object value = table.get( key );
+        if( value instanceof Number )
+        {
+            return ((Number) value).doubleValue();
+        }
+        else
+        {
+            throw badKey( key, "number", value );
+        }
     }
 
     public static int getIntField( @Nonnull Map<?, ?> table, @Nonnull String key ) throws LuaException
@@ -38,45 +62,11 @@ public final class TableHelper
         }
     }
 
-    @Nonnull
-    public static LuaException badKey( @Nonnull String key, @Nonnull String expected, @Nullable Object actual )
-    {
-        return badKey( key, expected, LuaValues.getType( actual ) );
-    }
-
-    @Nonnull
-    public static LuaException badKey( @Nonnull String key, @Nonnull String expected, @Nonnull String actual )
-    {
-        return new LuaException( "bad field '" + key + "' (" + expected + " expected, got " + actual + ")" );
-    }
-
     public static double getRealField( @Nonnull Map<?, ?> table, @Nonnull String key ) throws LuaException
     {
         return checkReal( key, getNumberField( table, key ) );
     }
 
-    private static double checkReal( @Nonnull String key, double value ) throws LuaException
-    {
-        if( !Double.isFinite( value ) )
-        {
-            throw badKey( key, "number", getNumericType( value ) );
-        }
-        return value;
-    }
-
-    public static double getNumberField( @Nonnull Map<?, ?> table, @Nonnull String key ) throws LuaException
-    {
-        Object value = table.get( key );
-        if( value instanceof Number )
-        {
-            return ((Number) value).doubleValue();
-        }
-        else
-        {
-            throw badKey( key, "number", value );
-        }
-    }
-
     public static boolean getBooleanField( @Nonnull Map<?, ?> table, @Nonnull String key ) throws LuaException
     {
         Object value = table.get( key );
@@ -119,6 +109,23 @@ public final class TableHelper
         }
     }
 
+    public static double optNumberField( @Nonnull Map<?, ?> table, @Nonnull String key, double def ) throws LuaException
+    {
+        Object value = table.get( key );
+        if( value == null )
+        {
+            return def;
+        }
+        else if( value instanceof Number )
+        {
+            return ((Number) value).doubleValue();
+        }
+        else
+        {
+            throw badKey( key, "number", value );
+        }
+    }
+
     public static int optIntField( @Nonnull Map<?, ?> table, @Nonnull String key, int def ) throws LuaException
     {
         Object value = table.get( key );
@@ -141,23 +148,6 @@ public final class TableHelper
         return checkReal( key, optNumberField( table, key, def ) );
     }
 
-    public static double optNumberField( @Nonnull Map<?, ?> table, @Nonnull String key, double def ) throws LuaException
-    {
-        Object value = table.get( key );
-        if( value == null )
-        {
-            return def;
-        }
-        else if( value instanceof Number )
-        {
-            return ((Number) value).doubleValue();
-        }
-        else
-        {
-            throw badKey( key, "number", value );
-        }
-    }
-
     public static boolean optBooleanField( @Nonnull Map<?, ?> table, @Nonnull String key, boolean def ) throws LuaException
     {
         Object value = table.get( key );
@@ -209,4 +199,10 @@ public final class TableHelper
             throw badKey( key, "table", value );
         }
     }
+
+    private static double checkReal( @Nonnull String key, double value ) throws LuaException
+    {
+        if( !Double.isFinite( value ) ) throw badKey( key, "number", getNumericType( value ) );
+        return value;
+    }
 }

src/main/java/dan200/computercraft/core/apis/TermAPI.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.lua.IArguments;
@@ -28,7 +27,7 @@ public class TermAPI extends TermMethods implements ILuaAPI
 
     public TermAPI( IAPIEnvironment environment )
     {
-        this.terminal = environment.getTerminal();
+        terminal = environment.getTerminal();
         this.environment = environment.getComputerEnvironment();
     }
 
@@ -49,10 +48,7 @@ public class TermAPI extends TermMethods implements ILuaAPI
      * @cc.treturn number The blue channel, will be between 0 and 1.
      * @see TermMethods#setPaletteColour(IArguments) To change the palette colour.
      */
-    @LuaFunction( {
-        "nativePaletteColour",
-        "nativePaletteColor"
-    } )
+    @LuaFunction( { "nativePaletteColour", "nativePaletteColor" } )
     public final Object[] nativePaletteColour( int colour ) throws LuaException
     {
         int actualColour = 15 - parseColour( colour );
@@ -61,10 +57,7 @@ public class TermAPI extends TermMethods implements ILuaAPI
         float[] rgb = c.getRGB();
 
         Object[] rgbObj = new Object[rgb.length];
-        for( int i = 0; i < rgbObj.length; ++i )
-        {
-            rgbObj[i] = rgb[i];
-        }
+        for( int i = 0; i < rgbObj.length; ++i ) rgbObj[i] = rgb[i];
         return rgbObj;
     }
 
@@ -72,12 +65,12 @@ public class TermAPI extends TermMethods implements ILuaAPI
     @Override
     public Terminal getTerminal()
     {
-        return this.terminal;
+        return terminal;
     }
 
     @Override
     public boolean isColour()
     {
-        return this.environment.isColour();
+        return environment.isColour();
     }
 }

src/main/java/dan200/computercraft/core/apis/TermMethods.java

@@ -22,10 +22,27 @@ import javax.annotation.Nonnull;
  */
 public abstract class TermMethods
 {
+    private static int getHighestBit( int group )
+    {
+        int bit = 0;
+        while( group > 0 )
+        {
+            group >>= 1;
+            bit++;
+        }
+        return bit;
+    }
+
+    @Nonnull
+    public abstract Terminal getTerminal() throws LuaException;
+
+    public abstract boolean isColour() throws LuaException;
+
     /**
      * Write {@code text} at the current cursor position, moving the cursor to the end of the text.
      *
-     * Unlike functions like {@code write} and {@code print}, this does not wrap the text - it simply copies the text to the current terminal line.
+     * Unlike functions like {@code write} and {@code print}, this does not wrap the text - it simply copies the
+     * text to the current terminal line.
      *
      * @param arguments The text to write.
      * @throws LuaException (hidden) If the terminal cannot be found.
@@ -35,7 +52,7 @@ public abstract class TermMethods
     public final void write( IArguments arguments ) throws LuaException
     {
         String text = StringUtil.toString( arguments.get( 0 ) );
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
             terminal.write( text );
@@ -43,14 +60,11 @@ public abstract class TermMethods
         }
     }
 
-    @Nonnull
-    public abstract Terminal getTerminal() throws LuaException;
-
     /**
      * Move all positions up (or down) by {@code y} pixels.
      *
-     * Every pixel in the terminal will be replaced by the line {@code y} pixels below it. If {@code y} is negative, it will copy pixels from above
-     * instead.
+     * Every pixel in the terminal will be replaced by the line {@code y} pixels below it. If {@code y} is negative, it
+     * will copy pixels from above instead.
      *
      * @param y The number of lines to move up by. This may be a negative number.
      * @throws LuaException (hidden) If the terminal cannot be found.
@@ -58,7 +72,7 @@ public abstract class TermMethods
     @LuaFunction
     public final void scroll( int y ) throws LuaException
     {
-        this.getTerminal().scroll( y );
+        getTerminal().scroll( y );
     }
 
     /**
@@ -72,11 +86,8 @@ public abstract class TermMethods
     @LuaFunction
     public final Object[] getCursorPos() throws LuaException
     {
-        Terminal terminal = this.getTerminal();
-        return new Object[] {
-            terminal.getCursorX() + 1,
-            terminal.getCursorY() + 1
-        };
+        Terminal terminal = getTerminal();
+        return new Object[] { terminal.getCursorX() + 1, terminal.getCursorY() + 1 };
     }
 
     /**
@@ -89,7 +100,7 @@ public abstract class TermMethods
     @LuaFunction
     public final void setCursorPos( int x, int y ) throws LuaException
     {
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
             terminal.setCursorPos( x - 1, y - 1 );
@@ -105,7 +116,7 @@ public abstract class TermMethods
     @LuaFunction
     public final boolean getCursorBlink() throws LuaException
     {
-        return this.getTerminal().getCursorBlink();
+        return getTerminal().getCursorBlink();
     }
 
     /**
@@ -117,7 +128,7 @@ public abstract class TermMethods
     @LuaFunction
     public final void setCursorBlink( boolean blink ) throws LuaException
     {
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
             terminal.setCursorBlink( blink );
@@ -135,11 +146,8 @@ public abstract class TermMethods
     @LuaFunction
     public final Object[] getSize() throws LuaException
     {
-        Terminal terminal = this.getTerminal();
-        return new Object[] {
-            terminal.getWidth(),
-            terminal.getHeight()
-        };
+        Terminal terminal = getTerminal();
+        return new Object[] { terminal.getWidth(), terminal.getHeight() };
     }
 
     /**
@@ -150,18 +158,19 @@ public abstract class TermMethods
     @LuaFunction
     public final void clear() throws LuaException
     {
-        this.getTerminal().clear();
+        getTerminal().clear();
     }
 
     /**
-     * Clears the line the cursor is currently on, filling it with the {@link #getBackgroundColour() current background colour}.
+     * Clears the line the cursor is currently on, filling it with the {@link #getBackgroundColour() current background
+     * colour}.
      *
      * @throws LuaException (hidden) If the terminal cannot be found.
      */
     @LuaFunction
     public final void clearLine() throws LuaException
     {
-        this.getTerminal().clearLine();
+        getTerminal().clearLine();
     }
 
     /**
@@ -171,13 +180,10 @@ public abstract class TermMethods
      * @throws LuaException (hidden) If the terminal cannot be found.
      * @cc.see colors For a list of colour constants, returned by this function.
      */
-    @LuaFunction( {
-        "getTextColour",
-        "getTextColor"
-    } )
+    @LuaFunction( { "getTextColour", "getTextColor" } )
     public final int getTextColour() throws LuaException
     {
-        return encodeColour( this.getTerminal().getTextColour() );
+        return encodeColour( getTerminal().getTextColour() );
     }
 
     /**
@@ -187,81 +193,44 @@ public abstract class TermMethods
      * @throws LuaException (hidden) If the terminal cannot be found.
      * @cc.see colors For a list of colour constants.
      */
-    @LuaFunction( {
-        "setTextColour",
-        "setTextColor"
-    } )
+    @LuaFunction( { "setTextColour", "setTextColor" } )
     public final void setTextColour( int colourArg ) throws LuaException
     {
         int colour = parseColour( colourArg );
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
             terminal.setTextColour( colour );
         }
     }
 
-    public static int parseColour( int colour ) throws LuaException
-    {
-        if( colour <= 0 )
-        {
-            throw new LuaException( "Colour out of range" );
-        }
-        colour = getHighestBit( colour ) - 1;
-        if( colour < 0 || colour > 15 )
-        {
-            throw new LuaException( "Colour out of range" );
-        }
-        return colour;
-    }
-
-    private static int getHighestBit( int group )
-    {
-        int bit = 0;
-        while( group > 0 )
-        {
-            group >>= 1;
-            bit++;
-        }
-        return bit;
-    }
-
-    public static int encodeColour( int colour )
-    {
-        return 1 << colour;
-    }
-
     /**
-     * Return the current background colour. This is used when {@link #write writing text} and {@link #clear clearing} the terminal.
+     * Return the current background colour. This is used when {@link #write writing text} and {@link #clear clearing}
+     * the terminal.
      *
      * @return The current background colour.
      * @throws LuaException (hidden) If the terminal cannot be found.
      * @cc.see colors For a list of colour constants, returned by this function.
      */
-    @LuaFunction( {
-        "getBackgroundColour",
-        "getBackgroundColor"
-    } )
+    @LuaFunction( { "getBackgroundColour", "getBackgroundColor" } )
     public final int getBackgroundColour() throws LuaException
     {
-        return encodeColour( this.getTerminal().getBackgroundColour() );
+        return encodeColour( getTerminal().getBackgroundColour() );
     }
 
     /**
-     * Set the current background colour. This is used when {@link #write writing text} and {@link #clear clearing} the terminal.
+     * Set the current background colour. This is used when {@link #write writing text} and {@link #clear clearing} the
+     * terminal.
      *
      * @param colourArg The new background colour.
      * @throws LuaException (hidden) If the terminal cannot be found.
      * @cc.see colors For a list of colour constants.
      */
-    @LuaFunction( {
-        "setBackgroundColour",
-        "setBackgroundColor"
-    } )
+    @LuaFunction( { "setBackgroundColour", "setBackgroundColor" } )
     public final void setBackgroundColour( int colourArg ) throws LuaException
     {
         int colour = parseColour( colourArg );
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
             terminal.setBackgroundColour( colour );
@@ -271,29 +240,27 @@ public abstract class TermMethods
     /**
      * Determine if this terminal supports colour.
      *
-     * Terminals which do not support colour will still allow writing coloured text/backgrounds, but it will be displayed in greyscale.
+     * Terminals which do not support colour will still allow writing coloured text/backgrounds, but it will be
+     * displayed in greyscale.
      *
      * @return Whether this terminal supports colour.
      * @throws LuaException (hidden) If the terminal cannot be found.
      */
-    @LuaFunction( {
-        "isColour",
-        "isColor"
-    } )
+    @LuaFunction( { "isColour", "isColor" } )
     public final boolean getIsColour() throws LuaException
     {
-        return this.isColour();
+        return isColour();
     }
 
-    public abstract boolean isColour() throws LuaException;
-
     /**
      * Writes {@code text} to the terminal with the specific foreground and background characters.
      *
-     * As with {@link #write(IArguments)}, the text will be written at the current cursor location, with the cursor moving to the end of the text.
+     * As with {@link #write(IArguments)}, the text will be written at the current cursor location, with the cursor
+     * moving to the end of the text.
      *
-     * {@code textColour} and {@code backgroundColour} must both be strings the same length as {@code text}. All characters represent a single hexadecimal
-     * digit, which is converted to one of CC's colours. For instance, {@code "a"} corresponds to purple.
+     * {@code textColour} and {@code backgroundColour} must both be strings the same length as {@code text}. All
+     * characters represent a single hexadecimal digit, which is converted to one of CC's colours. For instance,
+     * {@code "a"} corresponds to purple.
      *
      * @param text             The text to write.
      * @param textColour       The corresponding text colours.
@@ -302,8 +269,8 @@ public abstract class TermMethods
      * @cc.see colors For a list of colour constants, and their hexadecimal values.
      * @cc.usage Prints "Hello, world!" in rainbow text.
      * <pre>{@code
-     *     term.blit("Hello, world!","01234456789ab","0000000000000")
-     *     }</pre>
+     * term.blit("Hello, world!","01234456789ab","0000000000000")
+     * }</pre>
      */
     @LuaFunction
     public final void blit( String text, String textColour, String backgroundColour ) throws LuaException
@@ -313,7 +280,7 @@ public abstract class TermMethods
             throw new LuaException( "Arguments must be the same length" );
         }
 
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
             terminal.blit( text, textColour, backgroundColour );
@@ -324,38 +291,36 @@ public abstract class TermMethods
     /**
      * Set the palette for a specific colour.
      *
-     * ComputerCraft's palette system allows you to change how a specific colour should be displayed. For instance, you can make @{colors.red} <em>more
-     * red</em> by setting its palette to #FF0000. This does now allow you to draw more colours - you are still limited to 16 on the screen at one time -
-     * but you can change <em>which</em> colours are used.
+     * ComputerCraft's palette system allows you to change how a specific colour should be displayed. For instance, you
+     * can make @{colors.red} <em>more red</em> by setting its palette to #FF0000. This does now allow you to draw more
+     * colours - you are still limited to 16 on the screen at one time - but you can change <em>which</em> colours are
+     * used.
      *
      * @param args The new palette values.
      * @throws LuaException (hidden) If the terminal cannot be found.
      * @cc.tparam [1] number index The colour whose palette should be changed.
-     * @cc.tparam number colour A 24-bit integer representing the RGB value of the colour. For instance the integer `0xFF0000` corresponds to the colour
-     * #FF0000.
+     * @cc.tparam number colour A 24-bit integer representing the RGB value of the colour. For instance the integer
+     * `0xFF0000` corresponds to the colour #FF0000.
      * @cc.tparam [2] number index The colour whose palette should be changed.
      * @cc.tparam number r The intensity of the red channel, between 0 and 1.
      * @cc.tparam number g The intensity of the green channel, between 0 and 1.
      * @cc.tparam number b The intensity of the blue channel, between 0 and 1.
      * @cc.usage Change the @{colors.red|red colour} from the default #CC4C4C to #FF0000.
      * <pre>{@code
-     *     term.setPaletteColour(colors.red, 0xFF0000)
-     *     term.setTextColour(colors.red)
-     *     print("Hello, world!")
-     *     }</pre>
+     * term.setPaletteColour(colors.red, 0xFF0000)
+     * term.setTextColour(colors.red)
+     * print("Hello, world!")
+     * }</pre>
      * @cc.usage As above, but specifying each colour channel separately.
      * <pre>{@code
-     *     term.setPaletteColour(colors.red, 1, 0, 0)
-     *     term.setTextColour(colors.red)
-     *     print("Hello, world!")
-     *     }</pre>
+     * term.setPaletteColour(colors.red, 1, 0, 0)
+     * term.setTextColour(colors.red)
+     * print("Hello, world!")
+     * }</pre>
      * @cc.see colors.unpackRGB To convert from the 24-bit format to three separate channels.
      * @cc.see colors.packRGB To convert from three separate channels to the 24-bit format.
      */
-    @LuaFunction( {
-        "setPaletteColour",
-        "setPaletteColor"
-    } )
+    @LuaFunction( { "setPaletteColour", "setPaletteColor" } )
     public final void setPaletteColour( IArguments args ) throws LuaException
     {
         int colour = 15 - parseColour( args.getInt( 0 ) );
@@ -363,24 +328,17 @@ public abstract class TermMethods
         {
             int hex = args.getInt( 1 );
             double[] rgb = Palette.decodeRGB8( hex );
-            setColour( this.getTerminal(), colour, rgb[0], rgb[1], rgb[2] );
+            setColour( getTerminal(), colour, rgb[0], rgb[1], rgb[2] );
         }
         else
         {
             double r = args.getFiniteDouble( 1 );
             double g = args.getFiniteDouble( 2 );
             double b = args.getFiniteDouble( 3 );
-            setColour( this.getTerminal(), colour, r, g, b );
+            setColour( getTerminal(), colour, r, g, b );
         }
     }
 
-    public static void setColour( Terminal terminal, int colour, double r, double g, double b )
-    {
-        terminal.getPalette()
-            .setColour( colour, r, g, b );
-        terminal.setChanged();
-    }
-
     /**
      * Get the current palette for a specific colour.
      *
@@ -391,18 +349,34 @@ public abstract class TermMethods
      * @cc.treturn number The green channel, will be between 0 and 1.
      * @cc.treturn number The blue channel, will be between 0 and 1.
      */
-    @LuaFunction( {
-        "getPaletteColour",
-        "getPaletteColor"
-    } )
+    @LuaFunction( { "getPaletteColour", "getPaletteColor" } )
     public final Object[] getPaletteColour( int colourArg ) throws LuaException
     {
         int colour = 15 - parseColour( colourArg );
-        Terminal terminal = this.getTerminal();
+        Terminal terminal = getTerminal();
         synchronized( terminal )
         {
-            return ArrayUtils.toObject( terminal.getPalette()
-                .getColour( colour ) );
+            return ArrayUtils.toObject( terminal.getPalette().getColour( colour ) );
         }
     }
+
+    public static int parseColour( int colour ) throws LuaException
+    {
+        if( colour <= 0 ) throw new LuaException( "Colour out of range" );
+        colour = getHighestBit( colour ) - 1;
+        if( colour < 0 || colour > 15 ) throw new LuaException( "Colour out of range" );
+        return colour;
+    }
+
+
+    public static int encodeColour( int colour )
+    {
+        return 1 << colour;
+    }
+
+    public static void setColour( Terminal terminal, int colour, double r, double g, double b )
+    {
+        terminal.getPalette().setColour( colour, r, g, b );
+        terminal.setChanged();
+    }
 }

src/main/java/dan200/computercraft/core/apis/http/CheckUrl.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http;
 
 import dan200.computercraft.core.apis.IAPIEnvironment;
@@ -20,10 +19,12 @@ import java.util.concurrent.Future;
 public class CheckUrl extends Resource<CheckUrl>
 {
     private static final String EVENT = "http_check";
+
+    private Future<?> future;
+
     private final IAPIEnvironment environment;
     private final String address;
     private final URI uri;
-    private Future<?> future;
 
     public CheckUrl( ResourceGroup<CheckUrl> limiter, IAPIEnvironment environment, String address, URI uri )
     {
@@ -35,20 +36,14 @@ public class CheckUrl extends Resource<CheckUrl>
 
     public void run()
     {
-        if( this.isClosed() )
-        {
-            return;
-        }
-        this.future = NetworkUtils.EXECUTOR.submit( this::doRun );
-        this.checkClosed();
+        if( isClosed() ) return;
+        future = NetworkUtils.EXECUTOR.submit( this::doRun );
+        checkClosed();
     }
 
     private void doRun()
     {
-        if( this.isClosed() )
-        {
-            return;
-        }
+        if( isClosed() ) return;
 
         try
         {
@@ -56,17 +51,11 @@ public class CheckUrl extends Resource<CheckUrl>
             InetSocketAddress netAddress = NetworkUtils.getAddress( uri, ssl );
             NetworkUtils.getOptions( uri.getHost(), netAddress );
 
-            if( this.tryClose() )
-            {
-                this.environment.queueEvent( EVENT, this.address, true );
-            }
+            if( tryClose() ) environment.queueEvent( EVENT, address, true );
         }
         catch( HTTPRequestException e )
         {
-            if( this.tryClose() )
-            {
-                this.environment.queueEvent( EVENT, this.address, false, e.getMessage() );
-            }
+            if( tryClose() ) environment.queueEvent( EVENT, address, false, e.getMessage() );
         }
     }
 
@@ -74,6 +63,6 @@ public class CheckUrl extends Resource<CheckUrl>
     protected void dispose()
     {
         super.dispose();
-        this.future = closeFuture( this.future );
+        future = closeFuture( future );
     }
 }

src/main/java/dan200/computercraft/core/apis/http/HTTPRequestException.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http;
 
 public class HTTPRequestException extends Exception

src/main/java/dan200/computercraft/core/apis/http/NetworkUtils.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http;
 
 import dan200.computercraft.ComputerCraft;
@@ -12,12 +11,19 @@ import dan200.computercraft.core.apis.http.options.AddressRule;
 import dan200.computercraft.core.apis.http.options.Options;
 import dan200.computercraft.shared.util.ThreadUtils;
 import io.netty.buffer.ByteBuf;
+import io.netty.channel.ConnectTimeoutException;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.handler.codec.DecoderException;
+import io.netty.handler.codec.TooLongFrameException;
+import io.netty.handler.codec.http.websocketx.WebSocketHandshakeException;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.SslContextBuilder;
+import io.netty.handler.timeout.ReadTimeoutException;
 
+import javax.annotation.Nonnull;
 import javax.net.ssl.SSLException;
+import javax.net.ssl.SSLHandshakeException;
 import javax.net.ssl.TrustManagerFactory;
 import java.net.InetSocketAddress;
 import java.net.URI;
@@ -32,69 +38,35 @@ import java.util.concurrent.TimeUnit;
  */
 public final class NetworkUtils
 {
-    public static final ExecutorService EXECUTOR = new ThreadPoolExecutor( 4,
-        Integer.MAX_VALUE,
-        60L,
-        TimeUnit.SECONDS,
+    public static final ExecutorService EXECUTOR = new ThreadPoolExecutor(
+        4, Integer.MAX_VALUE,
+        60L, TimeUnit.SECONDS,
         new SynchronousQueue<>(),
         ThreadUtils.builder( "Network" )
             .setPriority( Thread.MIN_PRIORITY + (Thread.NORM_PRIORITY - Thread.MIN_PRIORITY) / 2 )
-            .build() );
+            .build()
+    );
 
-    public static final EventLoopGroup LOOP_GROUP = new NioEventLoopGroup( 4,
-        ThreadUtils.builder( "Netty" )
-            .setPriority( Thread.MIN_PRIORITY + (Thread.NORM_PRIORITY - Thread.MIN_PRIORITY) / 2 )
-            .build() );
-    private static final Object sslLock = new Object();
-    private static TrustManagerFactory trustManager;
-    private static SslContext sslContext;
-    private static boolean triedSslContext = false;
+    public static final EventLoopGroup LOOP_GROUP = new NioEventLoopGroup( 4, ThreadUtils.builder( "Netty" )
+        .setPriority( Thread.MIN_PRIORITY + (Thread.NORM_PRIORITY - Thread.MIN_PRIORITY) / 2 )
+        .build()
+    );
 
     private NetworkUtils()
     {
     }
 
-    public static SslContext getSslContext() throws HTTPRequestException
-    {
-        if( sslContext != null || triedSslContext )
-        {
-            return sslContext;
-        }
-        synchronized( sslLock )
-        {
-            if( sslContext != null || triedSslContext )
-            {
-                return sslContext;
-            }
-            try
-            {
-                return sslContext = SslContextBuilder.forClient()
-                    .trustManager( getTrustManager() )
-                    .build();
-            }
-            catch( SSLException e )
-            {
-                ComputerCraft.log.error( "Cannot construct SSL context", e );
-                triedSslContext = true;
-                sslContext = null;
-
-                throw new HTTPRequestException( "Cannot create a secure connection" );
-            }
-        }
-    }
+    private static final Object sslLock = new Object();
+    private static TrustManagerFactory trustManager;
+    private static SslContext sslContext;
+    private static boolean triedSslContext = false;
 
     private static TrustManagerFactory getTrustManager()
     {
-        if( trustManager != null )
-        {
-            return trustManager;
-        }
+        if( trustManager != null ) return trustManager;
         synchronized( sslLock )
         {
-            if( trustManager != null )
-            {
-                return trustManager;
-            }
+            if( trustManager != null ) return trustManager;
 
             TrustManagerFactory tmf = null;
             try
@@ -111,6 +83,30 @@ public final class NetworkUtils
         }
     }
 
+    public static SslContext getSslContext() throws HTTPRequestException
+    {
+        if( sslContext != null || triedSslContext ) return sslContext;
+        synchronized( sslLock )
+        {
+            if( sslContext != null || triedSslContext ) return sslContext;
+            try
+            {
+                return sslContext = SslContextBuilder
+                    .forClient()
+                    .trustManager( getTrustManager() )
+                    .build();
+            }
+            catch( SSLException e )
+            {
+                ComputerCraft.log.error( "Cannot construct SSL context", e );
+                triedSslContext = true;
+                sslContext = null;
+
+                throw new HTTPRequestException( "Cannot create a secure connection" );
+            }
+        }
+    }
+
     /**
      * Create a {@link InetSocketAddress} from a {@link java.net.URI}.
      *
@@ -139,15 +135,9 @@ public final class NetworkUtils
      */
     public static InetSocketAddress getAddress( String host, int port, boolean ssl ) throws HTTPRequestException
     {
-        if( port < 0 )
-        {
-            port = ssl ? 443 : 80;
-        }
+        if( port < 0 ) port = ssl ? 443 : 80;
         InetSocketAddress socketAddress = new InetSocketAddress( host, port );
-        if( socketAddress.isUnresolved() )
-        {
-            throw new HTTPRequestException( "Unknown host" );
-        }
+        if( socketAddress.isUnresolved() ) throw new HTTPRequestException( "Unknown host" );
         return socketAddress;
     }
 
@@ -162,10 +152,7 @@ public final class NetworkUtils
     public static Options getOptions( String host, InetSocketAddress address ) throws HTTPRequestException
     {
         Options options = AddressRule.apply( ComputerCraft.httpRules, host, address );
-        if( options.action == Action.DENY )
-        {
-            throw new HTTPRequestException( "Domain not permitted" );
-        }
+        if( options.action == Action.DENY ) throw new HTTPRequestException( "Domain not permitted" );
         return options;
     }
 
@@ -181,4 +168,29 @@ public final class NetworkUtils
         buffer.readBytes( bytes );
         return bytes;
     }
+
+    @Nonnull
+    public static String toFriendlyError( @Nonnull Throwable cause )
+    {
+        if( cause instanceof WebSocketHandshakeException || cause instanceof HTTPRequestException )
+        {
+            return cause.getMessage();
+        }
+        else if( cause instanceof TooLongFrameException )
+        {
+            return "Message is too large";
+        }
+        else if( cause instanceof ReadTimeoutException || cause instanceof ConnectTimeoutException )
+        {
+            return "Timed out";
+        }
+        else if( cause instanceof SSLHandshakeException || (cause instanceof DecoderException && cause.getCause() instanceof SSLHandshakeException) )
+        {
+            return "Could not create a secure connection";
+        }
+        else
+        {
+            return "Could not connect";
+        }
+    }
 }

src/main/java/dan200/computercraft/core/apis/http/Resource.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http;
 
 import dan200.computercraft.shared.util.IoUtil;
@@ -25,7 +24,6 @@ import java.util.function.Consumer;
  */
 public abstract class Resource<T extends Resource<T>> implements Closeable
 {
-    private static final ReferenceQueue<Object> QUEUE = new ReferenceQueue<>();
     private final AtomicBoolean closed = new AtomicBoolean( false );
     private final ResourceGroup<T> limiter;
 
@@ -34,66 +32,6 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
         this.limiter = limiter;
     }
 
-    protected static <T extends Closeable> T closeCloseable( T closeable )
-    {
-        IoUtil.closeQuietly( closeable );
-        return null;
-    }
-
-    protected static ChannelFuture closeChannel( ChannelFuture future )
-    {
-        if( future != null )
-        {
-            future.cancel( false );
-            Channel channel = future.channel();
-            if( channel != null && channel.isOpen() )
-            {
-                channel.close();
-            }
-        }
-
-        return null;
-    }
-
-    protected static <T extends Future<?>> T closeFuture( T future )
-    {
-        if( future != null )
-        {
-            future.cancel( true );
-        }
-        return null;
-    }
-
-    public static void cleanup()
-    {
-        Reference<?> reference;
-        while( (reference = QUEUE.poll()) != null )
-        {
-            ((CloseReference<?>) reference).resource.close();
-        }
-    }
-
-    @Override
-    public final void close()
-    {
-        this.tryClose();
-    }
-
-    /**
-     * Try to close the current resource.
-     *
-     * @return Whether this was successfully closed, or {@code false} if it has already been closed.
-     */
-    protected final boolean tryClose()
-    {
-        if( this.closed.getAndSet( true ) )
-        {
-            return false;
-        }
-        this.dispose();
-        return true;
-    }
-
     /**
      * Whether this resource is closed.
      *
@@ -101,7 +39,7 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
      */
     public final boolean isClosed()
     {
-        return this.closed.get();
+        return closed.get();
     }
 
     /**
@@ -111,24 +49,34 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
      */
     public final boolean checkClosed()
     {
-        if( !this.closed.get() )
-        {
-            return false;
-        }
-        this.dispose();
+        if( !closed.get() ) return false;
+        dispose();
+        return true;
+    }
+
+    /**
+     * Try to close the current resource.
+     *
+     * @return Whether this was successfully closed, or {@code false} if it has already been closed.
+     */
+    protected final boolean tryClose()
+    {
+        if( closed.getAndSet( true ) ) return false;
+        dispose();
         return true;
     }
 
     /**
      * Clean up any pending resources
      *
-     * Note, this may be called multiple times, and so should be thread-safe and avoid any major side effects.
+     * Note, this may be called multiple times, and so should be thread-safe and
+     * avoid any major side effects.
      */
     protected void dispose()
     {
         @SuppressWarnings( "unchecked" )
         T thisT = (T) this;
-        this.limiter.release( thisT );
+        limiter.release( thisT );
     }
 
     /**
@@ -143,13 +91,46 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
         return new CloseReference<>( this, object );
     }
 
-    public boolean queue( Consumer<T> task )
+    @Override
+    public final void close()
+    {
+        tryClose();
+    }
+
+    public final boolean queue( Consumer<T> task )
     {
         @SuppressWarnings( "unchecked" )
         T thisT = (T) this;
-        return this.limiter.queue( thisT, () -> task.accept( thisT ) );
+        return limiter.queue( thisT, () -> task.accept( thisT ) );
     }
 
+    protected static <T extends Closeable> T closeCloseable( T closeable )
+    {
+        IoUtil.closeQuietly( closeable );
+        return null;
+    }
+
+    protected static ChannelFuture closeChannel( ChannelFuture future )
+    {
+        if( future != null )
+        {
+            future.cancel( false );
+            Channel channel = future.channel();
+            if( channel != null && channel.isOpen() ) channel.close();
+        }
+
+        return null;
+    }
+
+    protected static <T extends Future<?>> T closeFuture( T future )
+    {
+        if( future != null ) future.cancel( true );
+        return null;
+    }
+
+
+    private static final ReferenceQueue<Object> QUEUE = new ReferenceQueue<>();
+
     private static class CloseReference<T> extends WeakReference<T>
     {
         final Resource<?> resource;
@@ -160,4 +141,10 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
             this.resource = resource;
         }
     }
+
+    public static void cleanup()
+    {
+        Reference<?> reference;
+        while( (reference = QUEUE.poll()) != null ) ((CloseReference<?>) reference).resource.close();
+    }
 }

src/main/java/dan200/computercraft/core/apis/http/ResourceGroup.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http;
 
 import java.util.Collections;
@@ -19,12 +18,17 @@ import java.util.function.Supplier;
  */
 public class ResourceGroup<T extends Resource<T>>
 {
+    public static final int DEFAULT_LIMIT = 512;
+    public static final IntSupplier DEFAULT = () -> DEFAULT_LIMIT;
+
     private static final IntSupplier ZERO = () -> 0;
 
     final IntSupplier limit;
-    final Set<T> resources = Collections.newSetFromMap( new ConcurrentHashMap<>() );
+
     boolean active = false;
 
+    final Set<T> resources = Collections.newSetFromMap( new ConcurrentHashMap<>() );
+
     public ResourceGroup( IntSupplier limit )
     {
         this.limit = limit;
@@ -32,23 +36,20 @@ public class ResourceGroup<T extends Resource<T>>
 
     public ResourceGroup()
     {
-        this.limit = ZERO;
+        limit = ZERO;
     }
 
     public void startup()
     {
-        this.active = true;
+        active = true;
     }
 
     public synchronized void shutdown()
     {
-        this.active = false;
+        active = false;
 
-        for( T resource : this.resources )
-        {
-            resource.close();
-        }
-        this.resources.clear();
+        for( T resource : resources ) resource.close();
+        resources.clear();
 
         Resource.cleanup();
     }
@@ -56,7 +57,7 @@ public class ResourceGroup<T extends Resource<T>>
 
     public final boolean queue( T resource, Runnable setup )
     {
-        return this.queue( () -> {
+        return queue( () -> {
             setup.run();
             return resource;
         } );
@@ -65,15 +66,12 @@ public class ResourceGroup<T extends Resource<T>>
     public synchronized boolean queue( Supplier<T> resource )
     {
         Resource.cleanup();
-        if( !this.active )
-        {
-            return false;
-        }
+        if( !active ) return false;
 
         int limit = this.limit.getAsInt();
-        if( limit <= 0 || this.resources.size() < limit )
+        if( limit <= 0 || resources.size() < limit )
         {
-            this.resources.add( resource.get() );
+            resources.add( resource.get() );
             return true;
         }
 
@@ -82,6 +80,6 @@ public class ResourceGroup<T extends Resource<T>>
 
     public synchronized void release( T resource )
     {
-        this.resources.remove( resource );
+        resources.remove( resource );
     }
 }

src/main/java/dan200/computercraft/core/apis/http/ResourceQueue.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http;
 
 import java.util.ArrayDeque;
@@ -32,21 +31,17 @@ public class ResourceQueue<T extends Resource<T>> extends ResourceGroup<T>
     public synchronized void shutdown()
     {
         super.shutdown();
-        this.pending.clear();
+        pending.clear();
     }
 
     @Override
     public synchronized boolean queue( Supplier<T> resource )
     {
-        if( !this.active )
-        {
-            return false;
-        }
+        if( !active ) return false;
+        if( super.queue( resource ) ) return true;
+        if( pending.size() > DEFAULT_LIMIT ) return false;
 
-        if( !super.queue( resource ) )
-        {
-            this.pending.add( resource );
-        }
+        pending.add( resource );
         return true;
     }
 
@@ -55,19 +50,13 @@ public class ResourceQueue<T extends Resource<T>> extends ResourceGroup<T>
     {
         super.release( resource );
 
-        if( !this.active )
-        {
-            return;
-        }
+        if( !active ) return;
 
         int limit = this.limit.getAsInt();
-        if( limit <= 0 || this.resources.size() < limit )
+        if( limit <= 0 || resources.size() < limit )
         {
-            Supplier<T> next = this.pending.poll();
-            if( next != null )
-            {
-                this.resources.add( next.get() );
-            }
+            Supplier<T> next = pending.poll();
+            if( next != null ) resources.add( next.get() );
         }
     }
 }

src/main/java/dan200/computercraft/core/apis/http/options/Action.java

@@ -9,13 +9,14 @@ import javax.annotation.Nonnull;
 
 public enum Action
 {
-    ALLOW, DENY;
+    ALLOW,
+    DENY;
 
     private final PartialOptions partial = new PartialOptions( this, null, null, null, null );
 
     @Nonnull
     public PartialOptions toPartial()
     {
-        return this.partial;
+        return partial;
     }
 }

src/main/java/dan200/computercraft/core/apis/http/options/AddressRule.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http.options;
 
 import com.google.common.net.InetAddresses;
@@ -62,6 +61,23 @@ public final class AddressRule
         }
     }
 
+    /**
+     * Determine whether the given address matches a series of patterns.
+     *
+     * @param domain      The domain to match
+     * @param port        The port of the address.
+     * @param address     The address to check.
+     * @param ipv4Address An ipv4 version of the address, if the original was an ipv6 address.
+     * @return Whether it matches any of these patterns.
+     */
+    private boolean matches( String domain, int port, InetAddress address, Inet4Address ipv4Address )
+    {
+        if( this.port != null && this.port != port ) return false;
+        return predicate.matches( domain )
+            || predicate.matches( address )
+            || (ipv4Address != null && predicate.matches( ipv4Address ));
+    }
+
     public static Options apply( Iterable<? extends AddressRule> rules, String domain, InetSocketAddress socketAddress )
     {
         PartialOptions options = null;
@@ -95,21 +111,4 @@ public final class AddressRule
 
         return (options == null ? PartialOptions.DEFAULT : options).toOptions();
     }
-
-    /**
-     * Determine whether the given address matches a series of patterns.
-     *
-     * @param domain      The domain to match
-     * @param port        The port of the address.
-     * @param address     The address to check.
-     * @param ipv4Address An ipv4 version of the address, if the original was an ipv6 address.
-     * @return Whether it matches any of these patterns.
-     */
-    private boolean matches( String domain, int port, InetAddress address, Inet4Address ipv4Address )
-    {
-        if( this.port != null && this.port != port ) return false;
-        return predicate.matches( domain )
-            || predicate.matches( address )
-            || (ipv4Address != null && predicate.matches( ipv4Address ));
-    }
 }

src/main/java/dan200/computercraft/core/apis/http/options/AddressRuleConfig.java

@@ -5,8 +5,8 @@
  */
 package dan200.computercraft.core.apis.http.options;
 
-
 import com.electronwill.nightconfig.core.CommentedConfig;
+import com.electronwill.nightconfig.core.Config;
 import com.electronwill.nightconfig.core.InMemoryCommentedFormat;
 import com.electronwill.nightconfig.core.UnmodifiableConfig;
 import dan200.computercraft.ComputerCraft;
@@ -16,10 +16,11 @@ import java.util.Locale;
 import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 
-
+/**
+ * Parses, checks and generates {@link Config}s for {@link AddressRule}.
+ */
 public class AddressRuleConfig
 {
-
     public static UnmodifiableConfig makeRule( String host, Action action )
     {
         CommentedConfig config = InMemoryCommentedFormat.defaultInstance().createConfig( ConcurrentHashMap::new );
@@ -61,10 +62,10 @@ public class AddressRuleConfig
     public static AddressRule parseRule( UnmodifiableConfig builder )
     {
         String hostObj = get( builder, "host", String.class ).orElse( null );
-        Integer port = get( builder, "port", Number.class ).map( Number::intValue ).orElse( null );
         if( hostObj == null ) return null;
 
         Action action = getEnum( builder, "action", Action.class ).orElse( null );
+        Integer port = get( builder, "port", Number.class ).map( Number::intValue ).orElse( null );
         Integer timeout = get( builder, "timeout", Number.class ).map( Number::intValue ).orElse( null );
         Long maxUpload = get( builder, "max_upload", Number.class ).map( Number::longValue ).orElse( null );
         Long maxDownload = get( builder, "max_download", Number.class ).map( Number::longValue ).orElse( null );

src/main/java/dan200/computercraft/core/apis/http/options/PartialOptions.java

@@ -31,43 +31,28 @@ public final class PartialOptions
     @Nonnull
     Options toOptions()
     {
-        if( this.options != null )
-        {
-            return this.options;
-        }
+        if( options != null ) return options;
 
-        return this.options = new Options( this.action == null ? Action.DENY : this.action,
-            this.maxUpload == null ? AddressRule.MAX_UPLOAD : this.maxUpload,
-            this.maxDownload == null ? AddressRule.MAX_DOWNLOAD : this.maxDownload,
-            this.timeout == null ? AddressRule.TIMEOUT : this.timeout, this.websocketMessage == null ? AddressRule.WEBSOCKET_MESSAGE : this.websocketMessage );
+        return options = new Options(
+            action == null ? Action.DENY : action,
+            maxUpload == null ? AddressRule.MAX_UPLOAD : maxUpload,
+            maxDownload == null ? AddressRule.MAX_DOWNLOAD : maxDownload,
+            timeout == null ? AddressRule.TIMEOUT : timeout,
+            websocketMessage == null ? AddressRule.WEBSOCKET_MESSAGE : websocketMessage
+        );
     }
 
     void merge( @Nonnull PartialOptions other )
     {
-        if( this.action == null && other.action != null )
-        {
-            this.action = other.action;
-        }
-        if( this.maxUpload == null && other.maxUpload != null )
-        {
-            this.maxUpload = other.maxUpload;
-        }
-        if( this.maxDownload == null && other.maxDownload != null )
-        {
-            this.maxDownload = other.maxDownload;
-        }
-        if( this.timeout == null && other.timeout != null )
-        {
-            this.timeout = other.timeout;
-        }
-        if( this.websocketMessage == null && other.websocketMessage != null )
-        {
-            this.websocketMessage = other.websocketMessage;
-        }
+        if( action == null && other.action != null ) action = other.action;
+        if( maxUpload == null && other.maxUpload != null ) maxUpload = other.maxUpload;
+        if( maxDownload == null && other.maxDownload != null ) maxDownload = other.maxDownload;
+        if( timeout == null && other.timeout != null ) timeout = other.timeout;
+        if( websocketMessage == null && other.websocketMessage != null ) websocketMessage = other.websocketMessage;
     }
 
     PartialOptions copy()
     {
-        return new PartialOptions( this.action, this.maxUpload, this.maxDownload, this.timeout, this.websocketMessage );
+        return new PartialOptions( action, maxUpload, maxDownload, timeout, websocketMessage );
     }
 }

src/main/java/dan200/computercraft/core/apis/http/request/HttpRequest.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http.request;
 
 import dan200.computercraft.ComputerCraft;
@@ -20,13 +19,10 @@ import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
-import io.netty.channel.ConnectTimeoutException;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
-import io.netty.handler.codec.TooLongFrameException;
 import io.netty.handler.codec.http.*;
 import io.netty.handler.ssl.SslContext;
-import io.netty.handler.timeout.ReadTimeoutException;
 import io.netty.handler.timeout.ReadTimeoutHandler;
 
 import java.net.InetSocketAddress;
@@ -48,26 +44,31 @@ public class HttpRequest extends Resource<HttpRequest>
     private static final String FAILURE_EVENT = "http_failure";
 
     private static final int MAX_REDIRECTS = 16;
-    final AtomicInteger redirects;
-    private final IAPIEnvironment environment;
-    private final String address;
-    private final ByteBuf postBuffer;
-    private final HttpHeaders headers;
-    private final boolean binary;
+
     private Future<?> executorFuture;
     private ChannelFuture connectFuture;
     private HttpRequestHandler currentRequest;
 
-    public HttpRequest( ResourceGroup<HttpRequest> limiter, IAPIEnvironment environment, String address, String postText, HttpHeaders headers,
-                        boolean binary, boolean followRedirects )
+    private final IAPIEnvironment environment;
+
+    private final String address;
+    private final ByteBuf postBuffer;
+    private final HttpHeaders headers;
+    private final boolean binary;
+
+    final AtomicInteger redirects;
+
+    public HttpRequest( ResourceGroup<HttpRequest> limiter, IAPIEnvironment environment, String address, String postText, HttpHeaders headers, boolean binary, boolean followRedirects )
     {
         super( limiter );
         this.environment = environment;
         this.address = address;
-        this.postBuffer = postText != null ? Unpooled.wrappedBuffer( postText.getBytes( StandardCharsets.UTF_8 ) ) : Unpooled.buffer( 0 );
+        postBuffer = postText != null
+            ? Unpooled.wrappedBuffer( postText.getBytes( StandardCharsets.UTF_8 ) )
+            : Unpooled.buffer( 0 );
         this.headers = headers;
         this.binary = binary;
-        this.redirects = new AtomicInteger( followRedirects ? MAX_REDIRECTS : 0 );
+        redirects = new AtomicInteger( followRedirects ? MAX_REDIRECTS : 0 );
 
         if( postText != null )
         {
@@ -78,11 +79,16 @@ public class HttpRequest extends Resource<HttpRequest>
 
             if( !headers.contains( HttpHeaderNames.CONTENT_LENGTH ) )
             {
-                headers.set( HttpHeaderNames.CONTENT_LENGTH, this.postBuffer.readableBytes() );
+                headers.set( HttpHeaderNames.CONTENT_LENGTH, postBuffer.readableBytes() );
             }
         }
     }
 
+    public IAPIEnvironment environment()
+    {
+        return environment;
+    }
+
     public static URI checkUri( String address ) throws HTTPRequestException
     {
         URI url;
@@ -102,73 +108,52 @@ public class HttpRequest extends Resource<HttpRequest>
     public static void checkUri( URI url ) throws HTTPRequestException
     {
         // Validate the URL
-        if( url.getScheme() == null )
-        {
-            throw new HTTPRequestException( "Must specify http or https" );
-        }
-        if( url.getHost() == null )
-        {
-            throw new HTTPRequestException( "URL malformed" );
-        }
+        if( url.getScheme() == null ) throw new HTTPRequestException( "Must specify http or https" );
+        if( url.getHost() == null ) throw new HTTPRequestException( "URL malformed" );
 
-        String scheme = url.getScheme()
-            .toLowerCase( Locale.ROOT );
+        String scheme = url.getScheme().toLowerCase( Locale.ROOT );
         if( !scheme.equalsIgnoreCase( "http" ) && !scheme.equalsIgnoreCase( "https" ) )
         {
             throw new HTTPRequestException( "Invalid protocol '" + scheme + "'" );
         }
     }
 
-    public IAPIEnvironment environment()
-    {
-        return this.environment;
-    }
-
     public void request( URI uri, HttpMethod method )
     {
-        if( this.isClosed() )
-        {
-            return;
-        }
-        this.executorFuture = NetworkUtils.EXECUTOR.submit( () -> this.doRequest( uri, method ) );
-        this.checkClosed();
+        if( isClosed() ) return;
+        executorFuture = NetworkUtils.EXECUTOR.submit( () -> doRequest( uri, method ) );
+        checkClosed();
     }
 
     private void doRequest( URI uri, HttpMethod method )
     {
         // If we're cancelled, abort.
-        if( this.isClosed() )
-        {
-            return;
-        }
+        if( isClosed() ) return;
 
         try
         {
-            boolean ssl = uri.getScheme()
-                .equalsIgnoreCase( "https" );
+            boolean ssl = uri.getScheme().equalsIgnoreCase( "https" );
             InetSocketAddress socketAddress = NetworkUtils.getAddress( uri, ssl );
             Options options = NetworkUtils.getOptions( uri.getHost(), socketAddress );
             SslContext sslContext = ssl ? NetworkUtils.getSslContext() : null;
 
             // getAddress may have a slight delay, so let's perform another cancellation check.
-            if( this.isClosed() )
-            {
-                return;
-            }
+            if( isClosed() ) return;
 
-            long requestBody = getHeaderSize( this.headers ) + this.postBuffer.capacity();
+            long requestBody = getHeaderSize( headers ) + postBuffer.capacity();
             if( options.maxUpload != 0 && requestBody > options.maxUpload )
             {
-                this.failure( "Request body is too large" );
+                failure( "Request body is too large" );
                 return;
             }
 
             // Add request size to the tracker before opening the connection
-            this.environment.addTrackingChange( TrackingField.HTTP_REQUESTS, 1 );
-            this.environment.addTrackingChange( TrackingField.HTTP_UPLOAD, requestBody );
+            environment.addTrackingChange( TrackingField.HTTP_REQUESTS, 1 );
+            environment.addTrackingChange( TrackingField.HTTP_UPLOAD, requestBody );
 
-            HttpRequestHandler handler = this.currentRequest = new HttpRequestHandler( this, uri, method, options );
-            this.connectFuture = new Bootstrap().group( NetworkUtils.LOOP_GROUP )
+            HttpRequestHandler handler = currentRequest = new HttpRequestHandler( this, uri, method, options );
+            connectFuture = new Bootstrap()
+                .group( NetworkUtils.LOOP_GROUP )
                 .channelFactory( NioSocketChannel::new )
                 .handler( new ChannelInitializer<SocketChannel>()
                 {
@@ -178,8 +163,7 @@ public class HttpRequest extends Resource<HttpRequest>
 
                         if( options.timeout > 0 )
                         {
-                            ch.config()
-                                .setConnectTimeoutMillis( options.timeout );
+                            ch.config().setConnectTimeoutMillis( options.timeout );
                         }
 
                         ChannelPipeline p = ch.pipeline();
@@ -193,93 +177,46 @@ public class HttpRequest extends Resource<HttpRequest>
                             p.addLast( new ReadTimeoutHandler( options.timeout, TimeUnit.MILLISECONDS ) );
                         }
 
-                        p.addLast( new HttpClientCodec(), new HttpContentDecompressor(), handler );
+                        p.addLast(
+                            new HttpClientCodec(),
+                            new HttpContentDecompressor(),
+                            handler
+                        );
                     }
                 } )
                 .remoteAddress( socketAddress )
                 .connect()
                 .addListener( c -> {
-                    if( !c.isSuccess() )
-                    {
-                        this.failure( c.cause() );
-                    }
+                    if( !c.isSuccess() ) failure( NetworkUtils.toFriendlyError( c.cause() ) );
                 } );
 
             // Do an additional check for cancellation
-            this.checkClosed();
+            checkClosed();
         }
         catch( HTTPRequestException e )
         {
-            this.failure( e.getMessage() );
+            failure( e.getMessage() );
         }
         catch( Exception e )
         {
-            this.failure( "Could not connect" );
-            if( ComputerCraft.logComputerErrors )
-            {
-                ComputerCraft.log.error( "Error in HTTP request", e );
-            }
+            failure( NetworkUtils.toFriendlyError( e ) );
+            if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error in HTTP request", e );
         }
     }
 
-    public static long getHeaderSize( HttpHeaders headers )
-    {
-        long size = 0;
-        for( Map.Entry<String, String> header : headers )
-        {
-            size += header.getKey() == null ? 0 : header.getKey()
-                .length();
-            size += header.getValue() == null ? 0 : header.getValue()
-                .length() + 1;
-        }
-        return size;
-    }
-
     void failure( String message )
     {
-        if( this.tryClose() )
-        {
-            this.environment.queueEvent( FAILURE_EVENT, this.address, message );
-        }
-    }
-
-    void failure( Throwable cause )
-    {
-        String message;
-        if( cause instanceof HTTPRequestException )
-        {
-            message = cause.getMessage();
-        }
-        else if( cause instanceof TooLongFrameException )
-        {
-            message = "Response is too large";
-        }
-        else if( cause instanceof ReadTimeoutException || cause instanceof ConnectTimeoutException )
-        {
-            message = "Timed out";
-        }
-        else
-        {
-            message = "Could not connect";
-        }
-
-        this.failure( message );
+        if( tryClose() ) environment.queueEvent( FAILURE_EVENT, address, message );
     }
 
     void failure( String message, HttpResponseHandle object )
     {
-        if( this.tryClose() )
-        {
-            this.environment.queueEvent( FAILURE_EVENT, this.address, message, object );
-        }
+        if( tryClose() ) environment.queueEvent( FAILURE_EVENT, address, message, object );
     }
 
     void success( HttpResponseHandle object )
     {
-        if( this.tryClose() )
-        {
-            this.environment.queueEvent( SUCCESS_EVENT, this.address, object );
-        }
+        if( tryClose() ) environment.queueEvent( SUCCESS_EVENT, address, object );
     }
 
     @Override
@@ -287,23 +224,34 @@ public class HttpRequest extends Resource<HttpRequest>
     {
         super.dispose();
 
-        this.executorFuture = closeFuture( this.executorFuture );
-        this.connectFuture = closeChannel( this.connectFuture );
-        this.currentRequest = closeCloseable( this.currentRequest );
+        executorFuture = closeFuture( executorFuture );
+        connectFuture = closeChannel( connectFuture );
+        currentRequest = closeCloseable( currentRequest );
+    }
+
+    public static long getHeaderSize( HttpHeaders headers )
+    {
+        long size = 0;
+        for( Map.Entry<String, String> header : headers )
+        {
+            size += header.getKey() == null ? 0 : header.getKey().length();
+            size += header.getValue() == null ? 0 : header.getValue().length() + 1;
+        }
+        return size;
     }
 
     public ByteBuf body()
     {
-        return this.postBuffer;
+        return postBuffer;
     }
 
     public HttpHeaders headers()
     {
-        return this.headers;
+        return headers;
     }
 
     public boolean isBinary()
     {
-        return this.binary;
+        return binary;
     }
 }

src/main/java/dan200/computercraft/core/apis/http/request/HttpRequestHandler.java

@@ -183,7 +183,7 @@ public final class HttpRequestHandler extends SimpleChannelInboundHandler<HttpOb
     public void exceptionCaught( ChannelHandlerContext ctx, Throwable cause )
     {
         if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error handling HTTP response", cause );
-        request.failure( cause );
+        request.failure( NetworkUtils.toFriendlyError( cause ) );
     }
 
     private void sendResponse()
@@ -256,4 +256,4 @@ public final class HttpRequestHandler extends SimpleChannelInboundHandler<HttpOb
             responseBody = null;
         }
     }
-}
+}

src/main/java/dan200/computercraft/core/apis/http/request/HttpResponseHandle.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http.request;
 
 import dan200.computercraft.api.lua.IArguments;
@@ -19,8 +18,9 @@ import java.util.Collections;
 import java.util.Map;
 
 /**
- * A http response. This provides the same methods as a {@link EncodedReadableHandle file} (or {@link BinaryReadableHandle binary file} if the request used
- * binary mode), though provides several request specific methods.
+ * A http response. This provides the same methods as a {@link EncodedReadableHandle file} (or
+ * {@link BinaryReadableHandle binary file} if the request used binary mode), though provides several request specific
+ * methods.
  *
  * @cc.module http.Response
  * @see HTTPAPI#request(IArguments)  On how to make a http request.
@@ -50,38 +50,36 @@ public class HttpResponseHandle implements ObjectSource
     @LuaFunction
     public final Object[] getResponseCode()
     {
-        return new Object[] {
-            this.responseCode,
-            this.responseStatus
-        };
+        return new Object[] { responseCode, responseStatus };
     }
 
     /**
-     * Get a table containing the response's headers, in a format similar to that required by {@link HTTPAPI#request}. If multiple headers are sent with the
-     * same name, they will be combined with a comma.
+     * Get a table containing the response's headers, in a format similar to that required by {@link HTTPAPI#request}.
+     * If multiple headers are sent with the same name, they will be combined with a comma.
      *
      * @return The response's headers.
-     * @cc.usage Make a request to [example.computercraft.cc](https://example.computercraft.cc), and print the returned headers.
+     * @cc.usage Make a request to [example.tweaked.cc](https://example.tweaked.cc), and print the
+     * returned headers.
      * <pre>{@code
-     *     local request = http.get("https://example.computercraft.cc")
-     *     print(textutils.serialize(request.getResponseHeaders()))
-     *     -- => {
-     *     --  [ "Content-Type" ] = "text/plain; charset=utf8",
-     *     --  [ "content-length" ] = 17,
-     *     --  ...
-     *     -- }
-     *     request.close()
-     *     }</pre>
+     * local request = http.get("https://example.tweaked.cc")
+     * print(textutils.serialize(request.getResponseHeaders()))
+     * -- => {
+     * --  [ "Content-Type" ] = "text/plain; charset=utf8",
+     * --  [ "content-length" ] = 17,
+     * --  ...
+     * -- }
+     * request.close()
+     * }</pre>
      */
     @LuaFunction
     public final Map<String, String> getResponseHeaders()
     {
-        return this.responseHeaders;
+        return responseHeaders;
     }
 
     @Override
     public Iterable<Object> getExtra()
     {
-        return Collections.singletonList( this.reader );
+        return Collections.singletonList( reader );
     }
 }

src/main/java/dan200/computercraft/core/apis/http/websocket/Websocket.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http.websocket;
 
 import com.google.common.base.Strings;
@@ -43,8 +42,8 @@ import java.util.concurrent.Future;
 public class Websocket extends Resource<Websocket>
 {
     /**
-     * We declare the maximum size to be 2^30 bytes. While messages can be much longer, we set an arbitrary limit as working with larger messages
-     * (especially within a Lua VM) is absurd.
+     * We declare the maximum size to be 2^30 bytes. While messages can be much longer, we set an arbitrary limit as
+     * working with larger messages (especially within a Lua VM) is absurd.
      */
     public static final int MAX_MESSAGE_SIZE = 1 << 30;
 
@@ -52,13 +51,15 @@ public class Websocket extends Resource<Websocket>
     static final String FAILURE_EVENT = "websocket_failure";
     static final String CLOSE_EVENT = "websocket_closed";
     static final String MESSAGE_EVENT = "websocket_message";
+
+    private Future<?> executorFuture;
+    private ChannelFuture connectFuture;
+    private WeakReference<WebsocketHandle> websocketHandle;
+
     private final IAPIEnvironment environment;
     private final URI uri;
     private final String address;
     private final HttpHeaders headers;
-    private Future<?> executorFuture;
-    private ChannelFuture connectFuture;
-    private WeakReference<WebsocketHandle> websocketHandle;
 
     public Websocket( ResourceGroup<Websocket> limiter, IAPIEnvironment environment, URI uri, String address, HttpHeaders headers )
     {
@@ -91,10 +92,7 @@ public class Websocket extends Resource<Websocket>
             }
         }
 
-        if( uri == null || uri.getHost() == null )
-        {
-            throw new HTTPRequestException( "URL malformed" );
-        }
+        if( uri == null || uri.getHost() == null ) throw new HTTPRequestException( "URL malformed" );
 
         String scheme = uri.getScheme();
         if( scheme == null )
@@ -118,38 +116,28 @@ public class Websocket extends Resource<Websocket>
 
     public void connect()
     {
-        if( this.isClosed() )
-        {
-            return;
-        }
-        this.executorFuture = NetworkUtils.EXECUTOR.submit( this::doConnect );
-        this.checkClosed();
+        if( isClosed() ) return;
+        executorFuture = NetworkUtils.EXECUTOR.submit( this::doConnect );
+        checkClosed();
     }
 
     private void doConnect()
     {
         // If we're cancelled, abort.
-        if( this.isClosed() )
-        {
-            return;
-        }
+        if( isClosed() ) return;
 
         try
         {
-            boolean ssl = this.uri.getScheme()
-                .equalsIgnoreCase( "wss" );
-
+            boolean ssl = uri.getScheme().equalsIgnoreCase( "wss" );
             InetSocketAddress socketAddress = NetworkUtils.getAddress( uri, ssl );
-            Options options = NetworkUtils.getOptions( this.uri.getHost(), socketAddress );
+            Options options = NetworkUtils.getOptions( uri.getHost(), socketAddress );
             SslContext sslContext = ssl ? NetworkUtils.getSslContext() : null;
 
             // getAddress may have a slight delay, so let's perform another cancellation check.
-            if( this.isClosed() )
-            {
-                return;
-            }
+            if( isClosed() ) return;
 
-            this.connectFuture = new Bootstrap().group( NetworkUtils.LOOP_GROUP )
+            connectFuture = new Bootstrap()
+                .group( NetworkUtils.LOOP_GROUP )
                 .channel( NioSocketChannel.class )
                 .handler( new ChannelInitializer<SocketChannel>()
                 {
@@ -159,81 +147,65 @@ public class Websocket extends Resource<Websocket>
                         ChannelPipeline p = ch.pipeline();
                         if( sslContext != null )
                         {
-                            p.addLast( sslContext.newHandler( ch.alloc(), Websocket.this.uri.getHost(), socketAddress.getPort() ) );
+                            p.addLast( sslContext.newHandler( ch.alloc(), uri.getHost(), socketAddress.getPort() ) );
                         }
 
-                        WebSocketClientHandshaker handshaker = WebSocketClientHandshakerFactory.newHandshaker( Websocket.this.uri,
-                            WebSocketVersion.V13,
-                            null,
-                            true,
-                            Websocket.this.headers,
-                            options.websocketMessage <= 0 ? MAX_MESSAGE_SIZE : options.websocketMessage );
+                        WebSocketClientHandshaker handshaker = WebSocketClientHandshakerFactory.newHandshaker(
+                            uri, WebSocketVersion.V13, null, true, headers,
+                            options.websocketMessage <= 0 ? MAX_MESSAGE_SIZE : options.websocketMessage
+                        );
 
-                        p.addLast( new HttpClientCodec(),
+                        p.addLast(
+                            new HttpClientCodec(),
                             new HttpObjectAggregator( 8192 ),
                             WebSocketClientCompressionHandler.INSTANCE,
-                            new WebsocketHandler( Websocket.this, handshaker, options ) );
+                            new WebsocketHandler( Websocket.this, handshaker, options )
+                        );
                     }
                 } )
                 .remoteAddress( socketAddress )
                 .connect()
                 .addListener( c -> {
-                    if( !c.isSuccess() )
-                    {
-                        this.failure( c.cause()
-                            .getMessage() );
-                    }
+                    if( !c.isSuccess() ) failure( NetworkUtils.toFriendlyError( c.cause() ) );
                 } );
 
             // Do an additional check for cancellation
-            this.checkClosed();
+            checkClosed();
         }
         catch( HTTPRequestException e )
         {
-            this.failure( e.getMessage() );
+            failure( e.getMessage() );
         }
         catch( Exception e )
         {
-            this.failure( "Could not connect" );
-            if( ComputerCraft.logComputerErrors )
-            {
-                ComputerCraft.log.error( "Error in websocket", e );
-            }
-        }
-    }
-
-    void failure( String message )
-    {
-        if( this.tryClose() )
-        {
-            this.environment.queueEvent( FAILURE_EVENT, this.address, message );
+            failure( NetworkUtils.toFriendlyError( e ) );
+            if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error in websocket", e );
         }
     }
 
     void success( Channel channel, Options options )
     {
-        if( this.isClosed() )
-        {
-            return;
-        }
+        if( isClosed() ) return;
 
         WebsocketHandle handle = new WebsocketHandle( this, options, channel );
-        this.environment().queueEvent( SUCCESS_EVENT, this.address, handle );
-        this.websocketHandle = this.createOwnerReference( handle );
+        environment().queueEvent( SUCCESS_EVENT, address, handle );
+        websocketHandle = createOwnerReference( handle );
 
-        this.checkClosed();
+        checkClosed();
     }
 
-    public IAPIEnvironment environment()
+    void failure( String message )
     {
-        return this.environment;
+        if( tryClose() ) environment.queueEvent( FAILURE_EVENT, address, message );
     }
 
     void close( int status, String reason )
     {
-        if( this.tryClose() )
+        if( tryClose() )
         {
-            this.environment.queueEvent( CLOSE_EVENT, this.address, Strings.isNullOrEmpty( reason ) ? null : reason, status < 0 ? null : status );
+            environment.queueEvent( CLOSE_EVENT, address,
+                Strings.isNullOrEmpty( reason ) ? null : reason,
+                status < 0 ? null : status );
         }
     }
 
@@ -242,17 +214,22 @@ public class Websocket extends Resource<Websocket>
     {
         super.dispose();
 
-        this.executorFuture = closeFuture( this.executorFuture );
-        this.connectFuture = closeChannel( this.connectFuture );
+        executorFuture = closeFuture( executorFuture );
+        connectFuture = closeChannel( connectFuture );
 
-        WeakReference<WebsocketHandle> websocketHandleRef = this.websocketHandle;
+        WeakReference<WebsocketHandle> websocketHandleRef = websocketHandle;
         WebsocketHandle websocketHandle = websocketHandleRef == null ? null : websocketHandleRef.get();
         IoUtil.closeQuietly( websocketHandle );
         this.websocketHandle = null;
     }
 
+    public IAPIEnvironment environment()
+    {
+        return environment;
+    }
+
     public String address()
     {
-        return this.address;
+        return address;
     }
 }

src/main/java/dan200/computercraft/core/apis/http/websocket/WebsocketHandle.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http.websocket;
 
 import com.google.common.base.Objects;
@@ -60,21 +59,14 @@ public class WebsocketHandle implements Closeable
     @LuaFunction
     public final MethodResult receive( Optional<Double> timeout ) throws LuaException
     {
-        this.checkOpen();
-        int timeoutId = timeout.isPresent() ? this.websocket.environment()
-            .startTimer( Math.round( checkFinite( 0, timeout.get() ) / 0.05 ) ) : -1;
+        checkOpen();
+        int timeoutId = timeout.isPresent()
+            ? websocket.environment().startTimer( Math.round( checkFinite( 0, timeout.get() ) / 0.05 ) )
+            : -1;
 
         return new ReceiveCallback( timeoutId ).pull;
     }
 
-    private void checkOpen() throws LuaException
-    {
-        if( this.closed )
-        {
-            throw new LuaException( "attempt to use a closed file" );
-        }
-    }
-
     /**
      * Send a websocket message to the connected server.
      *
@@ -86,39 +78,45 @@ public class WebsocketHandle implements Closeable
     @LuaFunction
     public final void send( Object message, Optional<Boolean> binary ) throws LuaException
     {
-        this.checkOpen();
+        checkOpen();
 
         String text = StringUtil.toString( message );
-        if( this.options.websocketMessage != 0 && text.length() > this.options.websocketMessage )
+        if( options.websocketMessage != 0 && text.length() > options.websocketMessage )
         {
             throw new LuaException( "Message is too large" );
         }
 
-        this.websocket.environment()
-            .addTrackingChange( TrackingField.WEBSOCKET_OUTGOING, text.length() );
+        websocket.environment().addTrackingChange( TrackingField.WEBSOCKET_OUTGOING, text.length() );
 
         Channel channel = this.channel;
         if( channel != null )
         {
-            channel.writeAndFlush( binary.orElse( false ) ? new BinaryWebSocketFrame( Unpooled.wrappedBuffer( LuaValues.encode( text ) ) ) : new TextWebSocketFrame(
-                text ) );
+            channel.writeAndFlush( binary.orElse( false )
+                ? new BinaryWebSocketFrame( Unpooled.wrappedBuffer( LuaValues.encode( text ) ) )
+                : new TextWebSocketFrame( text ) );
         }
     }
 
     /**
-     * Close this websocket. This will terminate the connection, meaning messages can no longer be sent or received along it.
+     * Close this websocket. This will terminate the connection, meaning messages can no longer be sent or received
+     * along it.
      */
     @LuaFunction( "close" )
     public final void doClose()
     {
-        this.close();
-        this.websocket.close();
+        close();
+        websocket.close();
+    }
+
+    private void checkOpen() throws LuaException
+    {
+        if( closed ) throw new LuaException( "attempt to use a closed file" );
     }
 
     @Override
     public void close()
     {
-        this.closed = true;
+        closed = true;
 
         Channel channel = this.channel;
         if( channel != null )
@@ -142,23 +140,23 @@ public class WebsocketHandle implements Closeable
         @Override
         public MethodResult resume( Object[] event )
         {
-            if( event.length >= 3 && Objects.equal( event[0], MESSAGE_EVENT ) && Objects.equal( event[1], WebsocketHandle.this.websocket.address() ) )
+            if( event.length >= 3 && Objects.equal( event[0], MESSAGE_EVENT ) && Objects.equal( event[1], websocket.address() ) )
             {
                 return MethodResult.of( Arrays.copyOfRange( event, 2, event.length ) );
             }
-            else if( event.length >= 2 && Objects.equal( event[0], CLOSE_EVENT ) && Objects.equal( event[1], WebsocketHandle.this.websocket.address() ) && WebsocketHandle.this.closed )
+            else if( event.length >= 2 && Objects.equal( event[0], CLOSE_EVENT ) && Objects.equal( event[1], websocket.address() ) && closed )
             {
                 // If the socket is closed abort.
                 return MethodResult.of();
             }
-            else if( event.length >= 2 && this.timeoutId != -1 && Objects.equal( event[0],
-                TIMER_EVENT ) && event[1] instanceof Number && ((Number) event[1]).intValue() == this.timeoutId )
+            else if( event.length >= 2 && timeoutId != -1 && Objects.equal( event[0], TIMER_EVENT )
+                && event[1] instanceof Number && ((Number) event[1]).intValue() == timeoutId )
             {
                 // If we received a matching timer event then abort.
                 return MethodResult.of();
             }
 
-            return this.pull;
+            return pull;
         }
     }
 }

src/main/java/dan200/computercraft/core/apis/http/websocket/WebsocketHandler.java

@@ -3,20 +3,15 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.apis.http.websocket;
 
-import dan200.computercraft.core.apis.http.HTTPRequestException;
 import dan200.computercraft.core.apis.http.NetworkUtils;
 import dan200.computercraft.core.apis.http.options.Options;
 import dan200.computercraft.core.tracking.TrackingField;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ConnectTimeoutException;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.handler.codec.TooLongFrameException;
 import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.websocketx.*;
-import io.netty.handler.timeout.ReadTimeoutException;
 import io.netty.util.CharsetUtil;
 
 import static dan200.computercraft.core.apis.http.websocket.Websocket.MESSAGE_EVENT;
@@ -37,70 +32,33 @@ public class WebsocketHandler extends SimpleChannelInboundHandler<Object>
     @Override
     public void channelActive( ChannelHandlerContext ctx ) throws Exception
     {
-        this.handshaker.handshake( ctx.channel() );
+        handshaker.handshake( ctx.channel() );
         super.channelActive( ctx );
     }
 
     @Override
     public void channelInactive( ChannelHandlerContext ctx ) throws Exception
     {
-        this.websocket.close( -1, "Websocket is inactive" );
+        websocket.close( -1, "Websocket is inactive" );
         super.channelInactive( ctx );
     }
 
-    @Override
-    public void exceptionCaught( ChannelHandlerContext ctx, Throwable cause )
-    {
-        ctx.close();
-
-        String message;
-        if( cause instanceof WebSocketHandshakeException || cause instanceof HTTPRequestException )
-        {
-            message = cause.getMessage();
-        }
-        else if( cause instanceof TooLongFrameException )
-        {
-            message = "Message is too large";
-        }
-        else if( cause instanceof ReadTimeoutException || cause instanceof ConnectTimeoutException )
-        {
-            message = "Timed out";
-        }
-        else
-        {
-            message = "Could not connect";
-        }
-
-        if( this.handshaker.isHandshakeComplete() )
-        {
-            this.websocket.close( -1, message );
-        }
-        else
-        {
-            this.websocket.failure( message );
-        }
-    }
-
     @Override
     public void channelRead0( ChannelHandlerContext ctx, Object msg )
     {
-        if( this.websocket.isClosed() )
-        {
-            return;
-        }
+        if( websocket.isClosed() ) return;
 
-        if( !this.handshaker.isHandshakeComplete() )
+        if( !handshaker.isHandshakeComplete() )
         {
-            this.handshaker.finishHandshake( ctx.channel(), (FullHttpResponse) msg );
-            this.websocket.success( ctx.channel(), this.options );
+            handshaker.finishHandshake( ctx.channel(), (FullHttpResponse) msg );
+            websocket.success( ctx.channel(), options );
             return;
         }
 
         if( msg instanceof FullHttpResponse )
         {
             FullHttpResponse response = (FullHttpResponse) msg;
-            throw new IllegalStateException( "Unexpected FullHttpResponse (getStatus=" + response.status() + ", content=" + response.content()
-                .toString( CharsetUtil.UTF_8 ) + ')' );
+            throw new IllegalStateException( "Unexpected FullHttpResponse (getStatus=" + response.status() + ", content=" + response.content().toString( CharsetUtil.UTF_8 ) + ')' );
         }
 
         WebSocketFrame frame = (WebSocketFrame) msg;
@@ -108,31 +66,41 @@ public class WebsocketHandler extends SimpleChannelInboundHandler<Object>
         {
             String data = ((TextWebSocketFrame) frame).text();
 
-            this.websocket.environment()
-                .addTrackingChange( TrackingField.WEBSOCKET_INCOMING, data.length() );
-            this.websocket.environment()
-                .queueEvent( MESSAGE_EVENT, this.websocket.address(), data, false );
+            websocket.environment().addTrackingChange( TrackingField.WEBSOCKET_INCOMING, data.length() );
+            websocket.environment().queueEvent( MESSAGE_EVENT, websocket.address(), data, false );
         }
         else if( frame instanceof BinaryWebSocketFrame )
         {
             byte[] converted = NetworkUtils.toBytes( frame.content() );
 
-            this.websocket.environment()
-                .addTrackingChange( TrackingField.WEBSOCKET_INCOMING, converted.length );
-            this.websocket.environment()
-                .queueEvent( MESSAGE_EVENT, this.websocket.address(), converted, true );
+            websocket.environment().addTrackingChange( TrackingField.WEBSOCKET_INCOMING, converted.length );
+            websocket.environment().queueEvent( MESSAGE_EVENT, websocket.address(), converted, true );
         }
         else if( frame instanceof CloseWebSocketFrame )
         {
             CloseWebSocketFrame closeFrame = (CloseWebSocketFrame) frame;
-            this.websocket.close( closeFrame.statusCode(), closeFrame.reasonText() );
+            websocket.close( closeFrame.statusCode(), closeFrame.reasonText() );
         }
         else if( frame instanceof PingWebSocketFrame )
         {
-            frame.content()
-                .retain();
-            ctx.channel()
-                .writeAndFlush( new PongWebSocketFrame( frame.content() ) );
+            frame.content().retain();
+            ctx.channel().writeAndFlush( new PongWebSocketFrame( frame.content() ) );
+        }
+    }
+
+    @Override
+    public void exceptionCaught( ChannelHandlerContext ctx, Throwable cause )
+    {
+        ctx.close();
+
+        String message = NetworkUtils.toFriendlyError( cause );
+        if( handshaker.isHandshakeComplete() )
+        {
+            websocket.close( -1, message );
+        }
+        else
+        {
+            websocket.failure( message );
         }
     }
 }

src/main/java/dan200/computercraft/core/asm/DeclaringClassLoader.java

@@ -18,6 +18,6 @@ final class DeclaringClassLoader extends ClassLoader
 
     Class<?> define( String name, byte[] bytes, ProtectionDomain protectionDomain ) throws ClassFormatError
     {
-        return this.defineClass( name, bytes, 0, bytes.length, protectionDomain );
+        return defineClass( name, bytes, 0, bytes.length, protectionDomain );
     }
 }

src/main/java/dan200/computercraft/core/asm/Generator.java

@@ -11,10 +11,7 @@ import com.google.common.cache.LoadingCache;
 import com.google.common.primitives.Primitives;
 import com.google.common.reflect.TypeToken;
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.api.lua.IArguments;
-import dan200.computercraft.api.lua.LuaException;
-import dan200.computercraft.api.lua.LuaFunction;
-import dan200.computercraft.api.lua.MethodResult;
+import dan200.computercraft.api.lua.*;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Type;
@@ -53,11 +50,15 @@ public final class Generator<T>
     private final String methodDesc;
 
     private final Function<T, T> wrap;
-    private final LoadingCache<Method, Optional<T>> methodCache = CacheBuilder.newBuilder()
-        .build( CacheLoader.from( catching( this::build, Optional.empty() ) ) );
-    private final LoadingCache<Class<?>, List<NamedMethod<T>>> classCache = CacheBuilder.newBuilder()
+
+    private final LoadingCache<Class<?>, List<NamedMethod<T>>> classCache = CacheBuilder
+        .newBuilder()
         .build( CacheLoader.from( catching( this::build, Collections.emptyList() ) ) );
 
+    private final LoadingCache<Method, Optional<T>> methodCache = CacheBuilder
+        .newBuilder()
+        .build( CacheLoader.from( catching( this::build, Optional.empty() ) ) );
+
     Generator( Class<T> base, List<Class<?>> context, Function<T, T> wrap )
     {
         this.base = base;
@@ -66,13 +67,8 @@ public final class Generator<T>
         this.wrap = wrap;
 
         StringBuilder methodDesc = new StringBuilder().append( "(Ljava/lang/Object;" );
-        for( Class<?> klass : context )
-        {
-            methodDesc.append( Type.getDescriptor( klass ) );
-        }
-        methodDesc.append( DESC_ARGUMENTS )
-            .append( ")" )
-            .append( DESC_METHOD_RESULT );
+        for( Class<?> klass : context ) methodDesc.append( Type.getDescriptor( klass ) );
+        methodDesc.append( DESC_ARGUMENTS ).append( ")" ).append( DESC_METHOD_RESULT );
         this.methodDesc = methodDesc.toString();
     }
 
@@ -81,7 +77,7 @@ public final class Generator<T>
     {
         try
         {
-            return this.classCache.get( klass );
+            return classCache.get( klass );
         }
         catch( ExecutionException e )
         {
@@ -97,10 +93,7 @@ public final class Generator<T>
         for( Method method : klass.getMethods() )
         {
             LuaFunction annotation = method.getAnnotation( LuaFunction.class );
-            if( annotation == null )
-            {
-                continue;
-            }
+            if( annotation == null ) continue;
 
             if( Modifier.isStatic( method.getModifiers() ) )
             {
@@ -108,52 +101,32 @@ public final class Generator<T>
                 continue;
             }
 
-            T instance = this.methodCache.getUnchecked( method )
-                .orElse( null );
-            if( instance == null )
-            {
-                continue;
-            }
+            T instance = methodCache.getUnchecked( method ).orElse( null );
+            if( instance == null ) continue;
 
-            if( methods == null )
-            {
-                methods = new ArrayList<>();
-            }
-            this.addMethod( methods, method, annotation, instance );
+            if( methods == null ) methods = new ArrayList<>();
+            addMethod( methods, method, annotation, instance );
         }
 
         for( GenericMethod method : GenericMethod.all() )
         {
             if( !method.target.isAssignableFrom( klass ) ) continue;
 
-            T instance = this.methodCache.getUnchecked( method.method )
-                .orElse( null );
-            if( instance == null )
-            {
-                continue;
-            }
+            T instance = methodCache.getUnchecked( method.method ).orElse( null );
+            if( instance == null ) continue;
 
-            if( methods == null )
-            {
-                methods = new ArrayList<>();
-            }
-            this.addMethod( methods, method.method, method.annotation, instance );
+            if( methods == null ) methods = new ArrayList<>();
+            addMethod( methods, method.method, method.annotation, instance );
         }
 
-        if( methods == null )
-        {
-            return Collections.emptyList();
-        }
+        if( methods == null ) return Collections.emptyList();
         methods.trimToSize();
         return Collections.unmodifiableList( methods );
     }
 
     private void addMethod( List<NamedMethod<T>> methods, Method method, LuaFunction annotation, T instance )
     {
-        if( annotation.mainThread() )
-        {
-            instance = this.wrap.apply( instance );
-        }
+        if( annotation.mainThread() ) instance = wrap.apply( instance );
 
         String[] names = annotation.value();
         boolean isSimple = method.getReturnType() != MethodResult.class && !annotation.mainThread();
@@ -173,8 +146,7 @@ public final class Generator<T>
     @Nonnull
     private Optional<T> build( Method method )
     {
-        String name = method.getDeclaringClass()
-            .getName() + "." + method.getName();
+        String name = method.getDeclaringClass().getName() + "." + method.getName();
         int modifiers = method.getModifiers();
 
         // Instance methods must be final - this prevents them being overridden and potentially exposed twice.
@@ -189,8 +161,7 @@ public final class Generator<T>
             return Optional.empty();
         }
 
-        if( !Modifier.isPublic( method.getDeclaringClass()
-            .getModifiers() ) )
+        if( !Modifier.isPublic( method.getDeclaringClass().getModifiers() ) )
         {
             ComputerCraft.log.error( "Lua Method {} should be on a public class.", name );
             return Optional.empty();
@@ -214,21 +185,12 @@ public final class Generator<T>
 
         try
         {
-            String className = method.getDeclaringClass()
-                .getName() + "$cc$" + method.getName() + METHOD_ID.getAndIncrement();
-            byte[] bytes = this.generate( className, target, method );
-            if( bytes == null )
-            {
-                return Optional.empty();
-            }
+            String className = method.getDeclaringClass().getName() + "$cc$" + method.getName() + METHOD_ID.getAndIncrement();
+            byte[] bytes = generate( className, target, method );
+            if( bytes == null ) return Optional.empty();
 
-            Class<?> klass = DeclaringClassLoader.INSTANCE.define( className,
-                bytes,
-                method.getDeclaringClass()
-                    .getProtectionDomain() );
-            return Optional.of( klass.asSubclass( this.base )
-                .getDeclaredConstructor()
-                .newInstance() );
+            Class<?> klass = DeclaringClassLoader.INSTANCE.define( className, bytes, method.getDeclaringClass().getProtectionDomain() );
+            return Optional.of( klass.asSubclass( base ).getDeclaredConstructor().newInstance() );
         }
         catch( ReflectiveOperationException | ClassFormatError | RuntimeException e )
         {
@@ -245,7 +207,7 @@ public final class Generator<T>
 
         // Construct a public final class which extends Object and implements MethodInstance.Delegate
         ClassWriter cw = new ClassWriter( ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS );
-        cw.visit( V1_8, ACC_PUBLIC | ACC_FINAL, internalName, null, "java/lang/Object", this.interfaces );
+        cw.visit( V1_8, ACC_PUBLIC | ACC_FINAL, internalName, null, "java/lang/Object", interfaces );
         cw.visitSource( "CC generated method", null );
 
         { // Constructor just invokes super.
@@ -259,7 +221,7 @@ public final class Generator<T>
         }
 
         {
-            MethodVisitor mw = cw.visitMethod( ACC_PUBLIC, METHOD_NAME, this.methodDesc, null, EXCEPTIONS );
+            MethodVisitor mw = cw.visitMethod( ACC_PUBLIC, METHOD_NAME, methodDesc, null, EXCEPTIONS );
             mw.visitCode();
 
             // If we're an instance method, load the this parameter.
@@ -272,22 +234,16 @@ public final class Generator<T>
             int argIndex = 0;
             for( java.lang.reflect.Type genericArg : method.getGenericParameterTypes() )
             {
-                Boolean loadedArg = this.loadArg( mw, target, method, genericArg, argIndex );
-                if( loadedArg == null )
-                {
-                    return null;
-                }
-                if( loadedArg )
-                {
-                    argIndex++;
-                }
+                Boolean loadedArg = loadArg( mw, target, method, genericArg, argIndex );
+                if( loadedArg == null ) return null;
+                if( loadedArg ) argIndex++;
             }
 
-            mw.visitMethodInsn( Modifier.isStatic( method.getModifiers() ) ? INVOKESTATIC : INVOKEVIRTUAL,
-                Type.getInternalName( method.getDeclaringClass() ),
-                method.getName(),
-                Type.getMethodDescriptor( method ),
-                false );
+            mw.visitMethodInsn(
+                Modifier.isStatic( method.getModifiers() ) ? INVOKESTATIC : INVOKEVIRTUAL,
+                Type.getInternalName( method.getDeclaringClass() ), method.getName(),
+                Type.getMethodDescriptor( method ), false
+            );
 
             // We allow a reasonable amount of flexibility on the return value's type. Alongside the obvious MethodResult,
             // we convert basic types into an immediate result.
@@ -301,11 +257,7 @@ public final class Generator<T>
                 else if( ret.isPrimitive() )
                 {
                     Class<?> boxed = Primitives.wrap( ret );
-                    mw.visitMethodInsn( INVOKESTATIC,
-                        Type.getInternalName( boxed ),
-                        "valueOf",
-                        "(" + Type.getDescriptor( ret ) + ")" + Type.getDescriptor( boxed ),
-                        false );
+                    mw.visitMethodInsn( INVOKESTATIC, Type.getInternalName( boxed ), "valueOf", "(" + Type.getDescriptor( ret ) + ")" + Type.getDescriptor( boxed ), false );
                     mw.visitMethodInsn( INVOKESTATIC, INTERNAL_METHOD_RESULT, "of", "(Ljava/lang/Object;)" + DESC_METHOD_RESULT, false );
                 }
                 else if( ret == Object[].class )
@@ -339,18 +291,15 @@ public final class Generator<T>
         }
 
         Class<?> arg = Reflect.getRawType( method, genericArg, true );
-        if( arg == null )
-        {
-            return null;
-        }
+        if( arg == null ) return null;
 
         if( arg == IArguments.class )
         {
-            mw.visitVarInsn( ALOAD, 2 + this.context.size() );
+            mw.visitVarInsn( ALOAD, 2 + context.size() );
             return false;
         }
 
-        int idx = this.context.indexOf( arg );
+        int idx = context.indexOf( arg );
         if( idx >= 0 )
         {
             mw.visitVarInsn( ALOAD, 2 + idx );
@@ -359,19 +308,12 @@ public final class Generator<T>
 
         if( arg == Optional.class )
         {
-            Class<?> klass = Reflect.getRawType( method,
-                TypeToken.of( genericArg )
-                    .resolveType( Reflect.OPTIONAL_IN )
-                    .getType(),
-                false );
-            if( klass == null )
-            {
-                return null;
-            }
+            Class<?> klass = Reflect.getRawType( method, TypeToken.of( genericArg ).resolveType( Reflect.OPTIONAL_IN ).getType(), false );
+            if( klass == null ) return null;
 
             if( Enum.class.isAssignableFrom( klass ) && klass != Enum.class )
             {
-                mw.visitVarInsn( ALOAD, 2 + this.context.size() );
+                mw.visitVarInsn( ALOAD, 2 + context.size() );
                 Reflect.loadInt( mw, argIndex );
                 mw.visitLdcInsn( Type.getType( klass ) );
                 mw.visitMethodInsn( INVOKEINTERFACE, INTERNAL_ARGUMENTS, "optEnum", "(ILjava/lang/Class;)Ljava/util/Optional;", true );
@@ -381,7 +323,7 @@ public final class Generator<T>
             String name = Reflect.getLuaName( Primitives.unwrap( klass ) );
             if( name != null )
             {
-                mw.visitVarInsn( ALOAD, 2 + this.context.size() );
+                mw.visitVarInsn( ALOAD, 2 + context.size() );
                 Reflect.loadInt( mw, argIndex );
                 mw.visitMethodInsn( INVOKEINTERFACE, INTERNAL_ARGUMENTS, "opt" + name, "(I)Ljava/util/Optional;", true );
                 return true;
@@ -390,7 +332,7 @@ public final class Generator<T>
 
         if( Enum.class.isAssignableFrom( arg ) && arg != Enum.class )
         {
-            mw.visitVarInsn( ALOAD, 2 + this.context.size() );
+            mw.visitVarInsn( ALOAD, 2 + context.size() );
             Reflect.loadInt( mw, argIndex );
             mw.visitLdcInsn( Type.getType( arg ) );
             mw.visitMethodInsn( INVOKEINTERFACE, INTERNAL_ARGUMENTS, "getEnum", "(ILjava/lang/Class;)Ljava/lang/Enum;", true );
@@ -401,22 +343,16 @@ public final class Generator<T>
         String name = arg == Object.class ? "" : Reflect.getLuaName( arg );
         if( name != null )
         {
-            if( Reflect.getRawType( method, genericArg, false ) == null )
-            {
-                return null;
-            }
+            if( Reflect.getRawType( method, genericArg, false ) == null ) return null;
 
-            mw.visitVarInsn( ALOAD, 2 + this.context.size() );
+            mw.visitVarInsn( ALOAD, 2 + context.size() );
             Reflect.loadInt( mw, argIndex );
             mw.visitMethodInsn( INVOKEINTERFACE, INTERNAL_ARGUMENTS, "get" + name, "(I)" + Type.getDescriptor( arg ), true );
             return true;
         }
 
         ComputerCraft.log.error( "Unknown parameter type {} for method {}.{}.",
-            arg.getName(),
-            method.getDeclaringClass()
-                .getName(),
-            method.getName() );
+            arg.getName(), method.getDeclaringClass().getName(), method.getName() );
         return null;
     }
 

src/main/java/dan200/computercraft/core/asm/IntCache.java

@@ -21,31 +21,19 @@ public final class IntCache<T>
     @SuppressWarnings( "unchecked" )
     public T get( int index )
     {
-        if( index < 0 )
-        {
-            throw new IllegalArgumentException( "index < 0" );
-        }
+        if( index < 0 ) throw new IllegalArgumentException( "index < 0" );
 
-        if( index < this.cache.length )
+        if( index < cache.length )
         {
-            T current = (T) this.cache[index];
-            if( current != null )
-            {
-                return current;
-            }
+            T current = (T) cache[index];
+            if( current != null ) return current;
         }
 
         synchronized( this )
         {
-            if( index >= this.cache.length )
-            {
-                this.cache = Arrays.copyOf( this.cache, Math.max( this.cache.length * 2, index + 1 ) );
-            }
-            T current = (T) this.cache[index];
-            if( current == null )
-            {
-                this.cache[index] = current = this.factory.apply( index );
-            }
+            if( index >= cache.length ) cache = Arrays.copyOf( cache, Math.max( cache.length * 2, index + 1 ) );
+            T current = (T) cache[index];
+            if( current == null ) cache[index] = current = factory.apply( index );
             return current;
         }
     }

src/main/java/dan200/computercraft/core/asm/LuaMethod.java

@@ -12,14 +12,13 @@ import java.util.Collections;
 
 public interface LuaMethod
 {
-    Generator<LuaMethod> GENERATOR = new Generator<>( LuaMethod.class,
-        Collections.singletonList( ILuaContext.class ),
-        m -> ( target, context, args ) -> TaskCallback.make( context,
-            () -> TaskCallback.checkUnwrap( m.apply( target,
-                context,
-                args ) ) ) );
+    Generator<LuaMethod> GENERATOR = new Generator<>( LuaMethod.class, Collections.singletonList( ILuaContext.class ),
+        m -> ( target, context, args ) -> TaskCallback.make( context, () -> TaskCallback.checkUnwrap( m.apply( target, context, args ) ) )
+    );
 
-    IntCache<LuaMethod> DYNAMIC = new IntCache<>( method -> ( instance, context, args ) -> ((IDynamicLuaObject) instance).callMethod( context, method, args ) );
+    IntCache<LuaMethod> DYNAMIC = new IntCache<>(
+        method -> ( instance, context, args ) -> ((IDynamicLuaObject) instance).callMethod( context, method, args )
+    );
 
     String[] EMPTY_METHODS = new String[0];
 

src/main/java/dan200/computercraft/core/asm/NamedMethod.java

@@ -23,17 +23,17 @@ public final class NamedMethod<T>
     @Nonnull
     public String getName()
     {
-        return this.name;
+        return name;
     }
 
     @Nonnull
     public T getMethod()
     {
-        return this.method;
+        return method;
     }
 
     public boolean nonYielding()
     {
-        return this.nonYielding;
+        return nonYielding;
     }
 }

src/main/java/dan200/computercraft/core/asm/ObjectSource.java

@@ -10,29 +10,23 @@ import java.util.function.BiConsumer;
 /**
  * A Lua object which exposes additional methods.
  *
- * This can be used to merge multiple objects together into one. Ideally this'd be part of the API, but I'm not entirely happy with the interface -
- * something I'd like to think about first.
+ * This can be used to merge multiple objects together into one. Ideally this'd be part of the API, but I'm not entirely
+ * happy with the interface - something I'd like to think about first.
  */
 public interface ObjectSource
 {
+    Iterable<Object> getExtra();
+
     static <T> void allMethods( Generator<T> generator, Object object, BiConsumer<Object, NamedMethod<T>> accept )
     {
-        for( NamedMethod<T> method : generator.getMethods( object.getClass() ) )
-        {
-            accept.accept( object, method );
-        }
+        for( NamedMethod<T> method : generator.getMethods( object.getClass() ) ) accept.accept( object, method );
 
         if( object instanceof ObjectSource )
         {
             for( Object extra : ((ObjectSource) object).getExtra() )
             {
-                for( NamedMethod<T> method : generator.getMethods( extra.getClass() ) )
-                {
-                    accept.accept( extra, method );
-                }
+                for( NamedMethod<T> method : generator.getMethods( extra.getClass() ) ) accept.accept( extra, method );
             }
         }
     }
-
-    Iterable<Object> getExtra();
 }

src/main/java/dan200/computercraft/core/asm/PeripheralMethod.java

@@ -17,19 +17,13 @@ import java.util.Arrays;
 
 public interface PeripheralMethod
 {
-    Generator<PeripheralMethod> GENERATOR = new Generator<>( PeripheralMethod.class,
-        Arrays.asList( ILuaContext.class, IComputerAccess.class ),
-        m -> ( target, context, computer, args ) -> TaskCallback.make( context,
-            () -> TaskCallback.checkUnwrap( m.apply(
-                target,
-                context,
-                computer,
-                args ) ) ) );
+    Generator<PeripheralMethod> GENERATOR = new Generator<>( PeripheralMethod.class, Arrays.asList( ILuaContext.class, IComputerAccess.class ),
+        m -> ( target, context, computer, args ) -> TaskCallback.make( context, () -> TaskCallback.checkUnwrap( m.apply( target, context, computer, args ) ) )
+    );
 
-    IntCache<PeripheralMethod> DYNAMIC = new IntCache<>( method -> ( instance, context, computer, args ) -> ((IDynamicPeripheral) instance).callMethod( computer,
-        context,
-        method,
-        args ) );
+    IntCache<PeripheralMethod> DYNAMIC = new IntCache<>(
+        method -> ( instance, context, computer, args ) -> ((IDynamicPeripheral) instance).callMethod( computer, context, method, args )
+    );
 
     @Nonnull
     MethodResult apply( @Nonnull Object target, @Nonnull ILuaContext context, @Nonnull IComputerAccess computer, @Nonnull IArguments args ) throws LuaException;

src/main/java/dan200/computercraft/core/asm/Reflect.java

@@ -29,37 +29,16 @@ final class Reflect
     {
         if( klass.isPrimitive() )
         {
-            if( klass == int.class )
-            {
-                return "Int";
-            }
-            if( klass == boolean.class )
-            {
-                return "Boolean";
-            }
-            if( klass == double.class )
-            {
-                return "Double";
-            }
-            if( klass == long.class )
-            {
-                return "Long";
-            }
+            if( klass == int.class ) return "Int";
+            if( klass == boolean.class ) return "Boolean";
+            if( klass == double.class ) return "Double";
+            if( klass == long.class ) return "Long";
         }
         else
         {
-            if( klass == Map.class )
-            {
-                return "Table";
-            }
-            if( klass == String.class )
-            {
-                return "String";
-            }
-            if( klass == ByteBuffer.class )
-            {
-                return "Bytes";
-            }
+            if( klass == Map.class ) return "Table";
+            if( klass == String.class ) return "String";
+            if( klass == ByteBuffer.class ) return "Bytes";
         }
 
         return null;
@@ -71,10 +50,7 @@ final class Reflect
         Type underlying = root;
         while( true )
         {
-            if( underlying instanceof Class<?> )
-            {
-                return (Class<?>) underlying;
-            }
+            if( underlying instanceof Class<?> ) return (Class<?>) underlying;
 
             if( underlying instanceof ParameterizedType )
             {
@@ -83,21 +59,13 @@ final class Reflect
                 {
                     for( java.lang.reflect.Type arg : type.getActualTypeArguments() )
                     {
-                        if( arg instanceof WildcardType )
-                        {
-                            continue;
-                        }
-                        if( arg instanceof TypeVariable && ((TypeVariable<?>) arg).getName()
-                            .startsWith( "capture#" ) )
+                        if( arg instanceof WildcardType ) continue;
+                        if( arg instanceof TypeVariable && ((TypeVariable<?>) arg).getName().startsWith( "capture#" ) )
                         {
                             continue;
                         }
 
-                        ComputerCraft.log.error( "Method {}.{} has generic type {} with non-wildcard argument {}.",
-                            method.getDeclaringClass(),
-                            method.getName(),
-                            root,
-                            arg );
+                        ComputerCraft.log.error( "Method {}.{} has generic type {} with non-wildcard argument {}.", method.getDeclaringClass(), method.getName(), root, arg );
                         return null;
                     }
                 }

src/main/java/dan200/computercraft/core/asm/TaskCallback.java

@@ -20,6 +20,33 @@ public final class TaskCallback implements ILuaCallback
         this.task = task;
     }
 
+    @Nonnull
+    @Override
+    public MethodResult resume( Object[] response ) throws LuaException
+    {
+        if( response.length < 3 || !(response[1] instanceof Number) || !(response[2] instanceof Boolean) )
+        {
+            return pull;
+        }
+
+        if( ((Number) response[1]).longValue() != task ) return pull;
+
+        if( (Boolean) response[2] )
+        {
+            // Extract the return values from the event and return them
+            return MethodResult.of( Arrays.copyOfRange( response, 3, response.length ) );
+        }
+        else if( response.length >= 4 && response[3] instanceof String )
+        {
+            // Extract the error message from the event and raise it
+            throw new LuaException( (String) response[3] );
+        }
+        else
+        {
+            throw new LuaException( "error" );
+        }
+    }
+
     static Object[] checkUnwrap( MethodResult result )
     {
         if( result.getCallback() != null )
@@ -37,34 +64,4 @@ public final class TaskCallback implements ILuaCallback
         long task = context.issueMainThreadTask( func );
         return new TaskCallback( task ).pull;
     }
-
-    @Nonnull
-    @Override
-    public MethodResult resume( Object[] response ) throws LuaException
-    {
-        if( response.length < 3 || !(response[1] instanceof Number) || !(response[2] instanceof Boolean) )
-        {
-            return this.pull;
-        }
-
-        if( ((Number) response[1]).longValue() != this.task )
-        {
-            return this.pull;
-        }
-
-        if( (Boolean) response[2] )
-        {
-            // Extract the return values from the event and return them
-            return MethodResult.of( Arrays.copyOfRange( response, 3, response.length ) );
-        }
-        else if( response.length >= 4 && response[3] instanceof String )
-        {
-            // Extract the error message from the event and raise it
-            throw new LuaException( (String) response[3] );
-        }
-        else
-        {
-            throw new LuaException( "error" );
-        }
-    }
 }

src/main/java/dan200/computercraft/core/computer/ApiWrapper.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.api.lua.ILuaAPI;
@@ -25,30 +24,30 @@ final class ApiWrapper implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return this.delegate.getNames();
+        return delegate.getNames();
     }
 
     @Override
     public void startup()
     {
-        this.delegate.startup();
+        delegate.startup();
     }
 
     @Override
     public void update()
     {
-        this.delegate.update();
+        delegate.update();
     }
 
     @Override
     public void shutdown()
     {
-        this.delegate.shutdown();
-        this.system.unmountAll();
+        delegate.shutdown();
+        system.unmountAll();
     }
 
     public ILuaAPI getDelegate()
     {
-        return this.delegate;
+        return delegate;
     }
 }

src/main/java/dan200/computercraft/core/computer/Computer.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import com.google.common.base.Objects;
@@ -31,79 +30,88 @@ import java.util.concurrent.atomic.AtomicBoolean;
 public class Computer
 {
     private static final int START_DELAY = 50;
+
+    // Various properties of the computer
+    private int id;
+    private String label = null;
+
     // Read-only fields about the computer
-    private final IComputerEnvironment m_environment;
-    private final Terminal m_terminal;
+    private final IComputerEnvironment environment;
+    private final Terminal terminal;
     private final ComputerExecutor executor;
     private final MainThreadExecutor serverExecutor;
+
+    // Additional state about the computer and its environment.
+    private boolean blinking = false;
     private final Environment internalEnvironment = new Environment( this );
     private final AtomicBoolean externalOutputChanged = new AtomicBoolean();
-    // Various properties of the computer
-    private int m_id;
-    private String m_label = null;
-    // Additional state about the computer and its environment.
-    private boolean m_blinking = false;
+
     private boolean startRequested;
-    private int m_ticksSinceStart = -1;
+    private int ticksSinceStart = -1;
 
     public Computer( IComputerEnvironment environment, Terminal terminal, int id )
     {
-        this.m_id = id;
-        this.m_environment = environment;
-        this.m_terminal = terminal;
+        this.id = id;
+        this.environment = environment;
+        this.terminal = terminal;
 
-        this.executor = new ComputerExecutor( this );
-        this.serverExecutor = new MainThreadExecutor( this );
+        executor = new ComputerExecutor( this );
+        serverExecutor = new MainThreadExecutor( this );
     }
 
     IComputerEnvironment getComputerEnvironment()
     {
-        return this.m_environment;
+        return environment;
     }
 
     FileSystem getFileSystem()
     {
-        return this.executor.getFileSystem();
+        return executor.getFileSystem();
     }
 
     Terminal getTerminal()
     {
-        return this.m_terminal;
+        return terminal;
     }
 
     public Environment getEnvironment()
     {
-        return this.internalEnvironment;
+        return internalEnvironment;
     }
 
     public IAPIEnvironment getAPIEnvironment()
     {
-        return this.internalEnvironment;
+        return internalEnvironment;
+    }
+
+    public boolean isOn()
+    {
+        return executor.isOn();
     }
 
     public void turnOn()
     {
-        this.startRequested = true;
+        startRequested = true;
     }
 
     public void shutdown()
     {
-        this.executor.queueStop( false, false );
+        executor.queueStop( false, false );
     }
 
     public void reboot()
     {
-        this.executor.queueStop( true, false );
+        executor.queueStop( true, false );
     }
 
     public void unload()
     {
-        this.executor.queueStop( false, true );
+        executor.queueStop( false, true );
     }
 
     public void queueEvent( String event, Object[] args )
     {
-        this.executor.queueEvent( event, args );
+        executor.queueEvent( event, args );
     }
 
     /**
@@ -114,107 +122,98 @@ public class Computer
      */
     public boolean queueMainThread( Runnable runnable )
     {
-        return this.serverExecutor.enqueue( runnable );
+        return serverExecutor.enqueue( runnable );
     }
 
     public IWorkMonitor getMainThreadMonitor()
     {
-        return this.serverExecutor;
+        return serverExecutor;
     }
 
     public int getID()
     {
-        return this.m_id;
-    }
-
-    public void setID( int id )
-    {
-        this.m_id = id;
+        return id;
     }
 
     public int assignID()
     {
-        if( this.m_id < 0 )
+        if( id < 0 )
         {
-            this.m_id = this.m_environment.assignNewID();
+            id = environment.assignNewID();
         }
-        return this.m_id;
+        return id;
+    }
+
+    public void setID( int id )
+    {
+        this.id = id;
     }
 
     public String getLabel()
     {
-        return this.m_label;
+        return label;
     }
 
     public void setLabel( String label )
     {
-        if( !Objects.equal( label, this.m_label ) )
+        if( !Objects.equal( label, this.label ) )
         {
-            this.m_label = label;
-            this.externalOutputChanged.set( true );
+            this.label = label;
+            externalOutputChanged.set( true );
         }
     }
 
     public void tick()
     {
         // We keep track of the number of ticks since the last start, only
-        if( this.m_ticksSinceStart >= 0 && this.m_ticksSinceStart <= START_DELAY )
-        {
-            this.m_ticksSinceStart++;
-        }
+        if( ticksSinceStart >= 0 && ticksSinceStart <= START_DELAY ) ticksSinceStart++;
 
-        if( this.startRequested && (this.m_ticksSinceStart < 0 || this.m_ticksSinceStart > START_DELAY) )
+        if( startRequested && (ticksSinceStart < 0 || ticksSinceStart > START_DELAY) )
         {
-            this.startRequested = false;
-            if( !this.executor.isOn() )
+            startRequested = false;
+            if( !executor.isOn() )
             {
-                this.m_ticksSinceStart = 0;
-                this.executor.queueStart();
+                ticksSinceStart = 0;
+                executor.queueStart();
             }
         }
 
-        this.executor.tick();
+        executor.tick();
 
         // Update the environment's internal state.
-        this.internalEnvironment.tick();
+        internalEnvironment.tick();
 
         // Propagate the environment's output to the world.
-        if( this.internalEnvironment.updateOutput() )
-        {
-            this.externalOutputChanged.set( true );
-        }
+        if( internalEnvironment.updateOutput() ) externalOutputChanged.set( true );
 
         // Set output changed if the terminal has changed from blinking to not
-        boolean blinking = this.m_terminal.getCursorBlink() && this.m_terminal.getCursorX() >= 0 && this.m_terminal.getCursorX() < this.m_terminal.getWidth() && this.m_terminal.getCursorY() >= 0 && this.m_terminal.getCursorY() < this.m_terminal.getHeight();
-        if( blinking != this.m_blinking )
+        boolean blinking = terminal.getCursorBlink() &&
+            terminal.getCursorX() >= 0 && terminal.getCursorX() < terminal.getWidth() &&
+            terminal.getCursorY() >= 0 && terminal.getCursorY() < terminal.getHeight();
+        if( blinking != this.blinking )
         {
-            this.m_blinking = blinking;
-            this.externalOutputChanged.set( true );
+            this.blinking = blinking;
+            externalOutputChanged.set( true );
         }
     }
 
     void markChanged()
     {
-        this.externalOutputChanged.set( true );
+        externalOutputChanged.set( true );
     }
 
     public boolean pollAndResetChanged()
     {
-        return this.externalOutputChanged.getAndSet( false );
+        return externalOutputChanged.getAndSet( false );
     }
 
     public boolean isBlinking()
     {
-        return this.isOn() && this.m_blinking;
-    }
-
-    public boolean isOn()
-    {
-        return this.executor.isOn();
+        return isOn() && blinking;
     }
 
     public void addApi( ILuaAPI api )
     {
-        this.executor.addApi( api );
+        executor.addApi( api );
     }
 }

src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.ComputerCraft;
@@ -33,38 +32,50 @@ import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantLock;
 
 /**
- * The main task queue and executor for a single computer. This handles turning on and off a computer, as well as running events.
+ * The main task queue and executor for a single computer. This handles turning on and off a computer, as well as
+ * running events.
  *
- * When the computer is instructed to turn on or off, or handle an event, we queue a task and register this to be executed on the {@link ComputerThread}.
- * Note, as we may be starting many events in a single tick, the external cannot lock on anything which may be held for a long time.
+ * When the computer is instructed to turn on or off, or handle an event, we queue a task and register this to be
+ * executed on the {@link ComputerThread}. Note, as we may be starting many events in a single tick, the external
+ * cannot lock on anything which may be held for a long time.
  *
- * The executor is effectively composed of two separate queues. Firstly, we have a "single element" queue {@link #command} which determines which state the
- * computer should transition too. This is set by {@link #queueStart()} and {@link #queueStop(boolean, boolean)}.
+ * The executor is effectively composed of two separate queues. Firstly, we have a "single element" queue
+ * {@link #command} which determines which state the computer should transition too. This is set by
+ * {@link #queueStart()} and {@link #queueStop(boolean, boolean)}.
  *
  * When a computer is on, we simply push any events onto to the {@link #eventQueue}.
  *
- * Both queues are run from the {@link #work()} method, which tries to execute a command if one exists, or resumes the machine with an event otherwise.
+ * Both queues are run from the {@link #work()} method, which tries to execute a command if one exists, or resumes the
+ * machine with an event otherwise.
  *
- * One final responsibility for the executor is calling {@link ILuaAPI#update()} every tick, via the {@link #tick()} method. This should only be called when
- * the computer is actually on ({@link #isOn}).
+ * One final responsibility for the executor is calling {@link ILuaAPI#update()} every tick, via the {@link #tick()}
+ * method. This should only be called when the computer is actually on ({@link #isOn}).
  */
 final class ComputerExecutor
 {
     private static final int QUEUE_LIMIT = 256;
-    final TimeoutState timeout = new TimeoutState();
-    /**
-     * The thread the executor is running on. This is non-null when performing work. We use this to ensure we're only doing one bit of work at one time.
-     *
-     * @see ComputerThread
-     */
-    final AtomicReference<Thread> executingThread = new AtomicReference<>();
+
     private final Computer computer;
     private final List<ILuaAPI> apis = new ArrayList<>();
+    final TimeoutState timeout = new TimeoutState();
+
+    private FileSystem fileSystem;
+
+    private ILuaMachine machine;
+
+    /**
+     * Whether the computer is currently on. This is set to false when a shutdown starts, or when turning on completes
+     * (but just before the Lua machine is started).
+     *
+     * @see #isOnLock
+     */
+    private volatile boolean isOn = false;
+
     /**
      * The lock to acquire when you need to modify the "on state" of a computer.
      *
-     * We hold this lock when running any command, and attempt to hold it when updating APIs. This ensures you don't update APIs while also
-     * starting/stopping them.
+     * We hold this lock when running any command, and attempt to hold it when updating APIs. This ensures you don't
+     * update APIs while also starting/stopping them.
      *
      * @see #isOn
      * @see #tick()
@@ -72,17 +83,13 @@ final class ComputerExecutor
      * @see #shutdown()
      */
     private final ReentrantLock isOnLock = new ReentrantLock();
+
     /**
-     * A lock used for any changes to {@link #eventQueue}, {@link #command} or {@link #onComputerQueue}. This will be used on the main thread, so locks
-     * should be kept as brief as possible.
+     * A lock used for any changes to {@link #eventQueue}, {@link #command} or {@link #onComputerQueue}. This will be
+     * used on the main thread, so locks should be kept as brief as possible.
      */
     private final Object queueLock = new Object();
-    /**
-     * The queue of events which should be executed when this computer is on.
-     *
-     * Note, this should be empty if this computer is off - it is cleared on shutdown and when turning on again.
-     */
-    private final Queue<Event> eventQueue = new ArrayDeque<>( 4 );
+
     /**
      * Determines if this executor is present within {@link ComputerThread}.
      *
@@ -91,37 +98,39 @@ final class ComputerExecutor
      * @see #afterWork()
      */
     volatile boolean onComputerQueue = false;
+
     /**
      * The amount of time this computer has used on a theoretical machine which shares work evenly amongst computers.
      *
      * @see ComputerThread
      */
     long virtualRuntime = 0;
+
     /**
      * The last time at which we updated {@link #virtualRuntime}.
      *
      * @see ComputerThread
      */
     long vRuntimeStart;
-    private FileSystem fileSystem;
-    private ILuaMachine machine;
-    /**
-     * Whether the computer is currently on. This is set to false when a shutdown starts, or when turning on completes (but just before the Lua machine is
-     * started).
-     *
-     * @see #isOnLock
-     */
-    private volatile boolean isOn = false;
+
     /**
      * The command that {@link #work()} should execute on the computer thread.
      *
-     * One sets the command with {@link #queueStart()} and {@link #queueStop(boolean, boolean)}. Neither of these will queue a new event if there is an
-     * existing one in the queue.
+     * One sets the command with {@link #queueStart()} and {@link #queueStop(boolean, boolean)}. Neither of these will
+     * queue a new event if there is an existing one in the queue.
      *
-     * Note, if command is not {@code null}, then some command is scheduled to be executed. Otherwise it is not currently in the queue (or is currently
-     * being executed).
+     * Note, if command is not {@code null}, then some command is scheduled to be executed. Otherwise it is not
+     * currently in the queue (or is currently being executed).
      */
     private volatile StateCommand command;
+
+    /**
+     * The queue of events which should be executed when this computer is on.
+     *
+     * Note, this should be empty if this computer is off - it is cleared on shutdown and when turning on again.
+     */
+    private final Queue<Event> eventQueue = new ArrayDeque<>( 4 );
+
     /**
      * Whether we interrupted an event and so should resume it instead of executing another task.
      *
@@ -129,14 +138,24 @@ final class ComputerExecutor
      * @see #resumeMachine(String, Object[])
      */
     private boolean interruptedEvent = false;
+
     /**
      * Whether this executor has been closed, and will no longer accept any incoming commands or events.
      *
      * @see #queueStop(boolean, boolean)
      */
     private boolean closed;
+
     private IWritableMount rootMount;
 
+    /**
+     * The thread the executor is running on. This is non-null when performing work. We use this to ensure we're only
+     * doing one bit of work at one time.
+     *
+     * @see ComputerThread
+     */
+    final AtomicReference<Thread> executingThread = new AtomicReference<>();
+
     ComputerExecutor( Computer computer )
     {
         // Ensure the computer thread is running as required.
@@ -147,41 +166,40 @@ final class ComputerExecutor
         Environment environment = computer.getEnvironment();
 
         // Add all default APIs to the loaded list.
-        this.apis.add( new TermAPI( environment ) );
-        this.apis.add( new RedstoneAPI( environment ) );
-        this.apis.add( new FSAPI( environment ) );
-        this.apis.add( new PeripheralAPI( environment ) );
-        this.apis.add( new OSAPI( environment ) );
-        if( ComputerCraft.httpEnabled )
-        {
-            this.apis.add( new HTTPAPI( environment ) );
-        }
+        apis.add( new TermAPI( environment ) );
+        apis.add( new RedstoneAPI( environment ) );
+        apis.add( new FSAPI( environment ) );
+        apis.add( new PeripheralAPI( environment ) );
+        apis.add( new OSAPI( environment ) );
+        if( ComputerCraft.httpEnabled ) apis.add( new HTTPAPI( environment ) );
 
         // Load in the externally registered APIs.
         for( ILuaAPIFactory factory : ApiFactories.getAll() )
         {
             ComputerSystem system = new ComputerSystem( environment );
             ILuaAPI api = factory.create( system );
-            if( api != null )
-            {
-                this.apis.add( new ApiWrapper( api, system ) );
-            }
+            if( api != null ) apis.add( new ApiWrapper( api, system ) );
         }
     }
 
     boolean isOn()
     {
-        return this.isOn;
+        return isOn;
     }
 
     FileSystem getFileSystem()
     {
-        return this.fileSystem;
+        return fileSystem;
+    }
+
+    Computer getComputer()
+    {
+        return computer;
     }
 
     void addApi( ILuaAPI api )
     {
-        this.apis.add( api );
+        apis.add( api );
     }
 
     /**
@@ -189,30 +207,13 @@ final class ComputerExecutor
      */
     void queueStart()
     {
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
             // We should only schedule a start if we're not currently on and there's turn on.
-            if( this.closed || this.isOn || this.command != null )
-            {
-                return;
-            }
+            if( closed || isOn || command != null ) return;
 
-            this.command = StateCommand.TURN_ON;
-            this.enqueue();
-        }
-    }
-
-    /**
-     * Add this executor to the {@link ComputerThread} if not already there.
-     */
-    private void enqueue()
-    {
-        synchronized( this.queueLock )
-        {
-            if( !this.onComputerQueue )
-            {
-                ComputerThread.queue( this );
-            }
+            command = StateCommand.TURN_ON;
+            enqueue();
         }
     }
 
@@ -225,54 +226,54 @@ final class ComputerExecutor
      */
     void queueStop( boolean reboot, boolean close )
     {
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
-            if( this.closed )
-            {
-                return;
-            }
-            this.closed = close;
+            if( closed ) return;
+            closed = close;
 
             StateCommand newCommand = reboot ? StateCommand.REBOOT : StateCommand.SHUTDOWN;
 
             // We should only schedule a stop if we're currently on and there's no shutdown pending.
-            if( !this.isOn || this.command != null )
+            if( !isOn || command != null )
             {
                 // If we're closing, set the command just in case.
-                if( close )
-                {
-                    this.command = newCommand;
-                }
+                if( close ) command = newCommand;
                 return;
             }
 
-            this.command = newCommand;
-            this.enqueue();
+            command = newCommand;
+            enqueue();
         }
     }
 
     /**
-     * Abort this whole computer due to a timeout. This will immediately destroy the Lua machine, and then schedule a shutdown.
+     * Abort this whole computer due to a timeout. This will immediately destroy the Lua machine,
+     * and then schedule a shutdown.
      */
     void abort()
     {
-        ILuaMachine machine = this.machine;
-        if( machine != null )
-        {
-            machine.close();
-        }
+        immediateFail( StateCommand.ABORT );
+    }
 
-        synchronized( this.queueLock )
+    /**
+     * Abort this whole computer due to an internal error. This will immediately destroy the Lua machine,
+     * and then schedule a shutdown.
+     */
+    void fastFail()
+    {
+        immediateFail( StateCommand.ERROR );
+    }
+
+    private void immediateFail( StateCommand command )
+    {
+        ILuaMachine machine = this.machine;
+        if( machine != null ) machine.close();
+
+        synchronized( queueLock )
         {
-            if( this.closed )
-            {
-                return;
-            }
-            this.command = StateCommand.ABORT;
-            if( this.isOn )
-            {
-                this.enqueue();
-            }
+            if( closed ) return;
+            this.command = command;
+            if( isOn ) enqueue();
         }
     }
 
@@ -285,23 +286,28 @@ final class ComputerExecutor
     void queueEvent( @Nonnull String event, @Nullable Object[] args )
     {
         // Events should be skipped if we're not on.
-        if( !this.isOn )
-        {
-            return;
-        }
+        if( !isOn ) return;
 
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
             // And if we've got some command in the pipeline, then don't queue events - they'll
             // probably be disposed of anyway.
             // We also limit the number of events which can be queued.
-            if( this.closed || this.command != null || this.eventQueue.size() >= QUEUE_LIMIT )
-            {
-                return;
-            }
+            if( closed || command != null || eventQueue.size() >= QUEUE_LIMIT ) return;
 
-            this.eventQueue.offer( new Event( event, args ) );
-            this.enqueue();
+            eventQueue.offer( new Event( event, args ) );
+            enqueue();
+        }
+    }
+
+    /**
+     * Add this executor to the {@link ComputerThread} if not already there.
+     */
+    private void enqueue()
+    {
+        synchronized( queueLock )
+        {
+            if( !onComputerQueue ) ComputerThread.queue( this );
         }
     }
 
@@ -310,7 +316,7 @@ final class ComputerExecutor
      */
     void tick()
     {
-        if( this.isOn && this.isOnLock.tryLock() )
+        if( isOn && isOnLock.tryLock() )
         {
             // This horrific structure means we don't try to update APIs while the state is being changed
             // (and so they may be running startup/shutdown).
@@ -318,29 +324,191 @@ final class ComputerExecutor
             // beginning or end of a computer's lifetime.
             try
             {
-                if( this.isOn )
+                if( isOn )
                 {
                     // Advance our APIs.
-                    for( ILuaAPI api : this.apis )
-                    {
-                        api.update();
-                    }
+                    for( ILuaAPI api : apis ) api.update();
                 }
             }
             finally
             {
-                this.isOnLock.unlock();
+                isOnLock.unlock();
             }
         }
     }
 
+    private IMount getRomMount()
+    {
+        return computer.getComputerEnvironment().createResourceMount( "computercraft", "lua/rom" );
+    }
+
+    private IWritableMount getRootMount()
+    {
+        if( rootMount == null )
+        {
+            rootMount = computer.getComputerEnvironment().createSaveDirMount(
+                "computer/" + computer.assignID(),
+                computer.getComputerEnvironment().getComputerSpaceLimit()
+            );
+        }
+        return rootMount;
+    }
+
+    private FileSystem createFileSystem()
+    {
+        FileSystem filesystem = null;
+        try
+        {
+            filesystem = new FileSystem( "hdd", getRootMount() );
+
+            IMount romMount = getRomMount();
+            if( romMount == null )
+            {
+                displayFailure( "Cannot mount ROM", null );
+                return null;
+            }
+
+            filesystem.mount( "rom", "rom", romMount );
+            return filesystem;
+        }
+        catch( FileSystemException e )
+        {
+            if( filesystem != null ) filesystem.close();
+            ComputerCraft.log.error( "Cannot mount computer filesystem", e );
+
+            displayFailure( "Cannot mount computer system", null );
+            return null;
+        }
+    }
+
+    private ILuaMachine createLuaMachine()
+    {
+        // Load the bios resource
+        InputStream biosStream = null;
+        try
+        {
+            biosStream = computer.getComputerEnvironment().createResourceFile( "computercraft", "lua/bios.lua" );
+        }
+        catch( Exception ignored )
+        {
+        }
+
+        if( biosStream == null )
+        {
+            displayFailure( "Error loading bios.lua", null );
+            return null;
+        }
+
+        // Create the lua machine
+        ILuaMachine machine = new CobaltLuaMachine( computer, timeout );
+
+        // Add the APIs. We unwrap them (yes, this is horrible) to get access to the underlying object.
+        for( ILuaAPI api : apis ) machine.addAPI( api instanceof ApiWrapper ? ((ApiWrapper) api).getDelegate() : api );
+
+        // Start the machine running the bios resource
+        MachineResult result = machine.loadBios( biosStream );
+        IoUtil.closeQuietly( biosStream );
+
+        if( result.isError() )
+        {
+            machine.close();
+            displayFailure( "Error loading bios.lua", result.getMessage() );
+            return null;
+        }
+
+        return machine;
+    }
+
+    private void turnOn() throws InterruptedException
+    {
+        isOnLock.lockInterruptibly();
+        try
+        {
+            // Reset the terminal and event queue
+            computer.getTerminal().reset();
+            interruptedEvent = false;
+            synchronized( queueLock )
+            {
+                eventQueue.clear();
+            }
+
+            // Init filesystem
+            if( (fileSystem = createFileSystem()) == null )
+            {
+                shutdown();
+                return;
+            }
+
+            // Init APIs
+            computer.getEnvironment().reset();
+            for( ILuaAPI api : apis ) api.startup();
+
+            // Init lua
+            if( (machine = createLuaMachine()) == null )
+            {
+                shutdown();
+                return;
+            }
+
+            // Initialisation has finished, so let's mark ourselves as on.
+            isOn = true;
+            computer.markChanged();
+        }
+        finally
+        {
+            isOnLock.unlock();
+        }
+
+        // Now actually start the computer, now that everything is set up.
+        resumeMachine( null, null );
+    }
+
+    private void shutdown() throws InterruptedException
+    {
+        isOnLock.lockInterruptibly();
+        try
+        {
+            isOn = false;
+            interruptedEvent = false;
+            synchronized( queueLock )
+            {
+                eventQueue.clear();
+            }
+
+            // Shutdown Lua machine
+            if( machine != null )
+            {
+                machine.close();
+                machine = null;
+            }
+
+            // Shutdown our APIs
+            for( ILuaAPI api : apis ) api.shutdown();
+            computer.getEnvironment().reset();
+
+            // Unload filesystem
+            if( fileSystem != null )
+            {
+                fileSystem.close();
+                fileSystem = null;
+            }
+
+            computer.getEnvironment().resetOutput();
+            computer.markChanged();
+        }
+        finally
+        {
+            isOnLock.unlock();
+        }
+    }
+
     /**
      * Called before calling {@link #work()}, setting up any important state.
      */
     void beforeWork()
     {
-        this.vRuntimeStart = System.nanoTime();
-        this.timeout.startTimer();
+        vRuntimeStart = System.nanoTime();
+        timeout.startTimer();
     }
 
     /**
@@ -350,35 +518,24 @@ final class ComputerExecutor
      */
     boolean afterWork()
     {
-        if( this.interruptedEvent )
+        if( interruptedEvent )
         {
-            this.timeout.pauseTimer();
+            timeout.pauseTimer();
         }
         else
         {
-            this.timeout.stopTimer();
+            timeout.stopTimer();
         }
 
-        Tracking.addTaskTiming( this.getComputer(), this.timeout.nanoCurrent() );
+        Tracking.addTaskTiming( getComputer(), timeout.nanoCurrent() );
 
-        if( this.interruptedEvent )
+        if( interruptedEvent ) return true;
+
+        synchronized( queueLock )
         {
+            if( eventQueue.isEmpty() && command == null ) return onComputerQueue = false;
             return true;
         }
-
-        synchronized( this.queueLock )
-        {
-            if( this.eventQueue.isEmpty() && this.command == null )
-            {
-                return this.onComputerQueue = false;
-            }
-            return true;
-        }
-    }
-
-    Computer getComputer()
-    {
-        return this.computer;
     }
 
     /**
@@ -392,19 +549,19 @@ final class ComputerExecutor
      */
     void work() throws InterruptedException
     {
-        if( this.interruptedEvent )
+        if( interruptedEvent )
         {
-            this.interruptedEvent = false;
-            if( this.machine != null )
+            interruptedEvent = false;
+            if( machine != null )
             {
-                this.resumeMachine( null, null );
+                resumeMachine( null, null );
                 return;
             }
         }
 
         StateCommand command;
         Event event = null;
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
             command = this.command;
             this.command = null;
@@ -412,15 +569,15 @@ final class ComputerExecutor
             // If we've no command, pull something from the event queue instead.
             if( command == null )
             {
-                if( !this.isOn )
+                if( !isOn )
                 {
                     // We're not on and had no command, but we had work queued. This should never happen, so clear
                     // the event queue just in case.
-                    this.eventQueue.clear();
+                    eventQueue.clear();
                     return;
                 }
 
-                event = this.eventQueue.poll();
+                event = eventQueue.poll();
             }
         }
 
@@ -429,170 +586,52 @@ final class ComputerExecutor
             switch( command )
             {
                 case TURN_ON:
-                    if( this.isOn )
-                    {
-                        return;
-                    }
-                    this.turnOn();
+                    if( isOn ) return;
+                    turnOn();
                     break;
 
                 case SHUTDOWN:
 
-                    if( !this.isOn )
-                    {
-                        return;
-                    }
-                    this.computer.getTerminal()
-                        .reset();
-                    this.shutdown();
+                    if( !isOn ) return;
+                    computer.getTerminal().reset();
+                    shutdown();
                     break;
 
                 case REBOOT:
-                    if( !this.isOn )
-                    {
-                        return;
-                    }
-                    this.computer.getTerminal()
-                        .reset();
-                    this.shutdown();
+                    if( !isOn ) return;
+                    computer.getTerminal().reset();
+                    shutdown();
 
-                    this.computer.turnOn();
+                    computer.turnOn();
                     break;
 
                 case ABORT:
-                    if( !this.isOn )
-                    {
-                        return;
-                    }
-                    this.displayFailure( "Error running computer", TimeoutState.ABORT_MESSAGE );
-                    this.shutdown();
+                    if( !isOn ) return;
+                    displayFailure( "Error running computer", TimeoutState.ABORT_MESSAGE );
+                    shutdown();
+                    break;
+
+                case ERROR:
+                    if( !isOn ) return;
+                    displayFailure( "Error running computer", "An internal error occurred, see logs." );
+                    shutdown();
                     break;
             }
         }
         else if( event != null )
         {
-            this.resumeMachine( event.name, event.args );
-        }
-    }
-
-    private void resumeMachine( String event, Object[] args ) throws InterruptedException
-    {
-        MachineResult result = this.machine.handleEvent( event, args );
-        this.interruptedEvent = result.isPause();
-        if( !result.isError() )
-        {
-            return;
-        }
-
-        this.displayFailure( "Error running computer", result.getMessage() );
-        this.shutdown();
-    }
-
-    private void turnOn() throws InterruptedException
-    {
-        this.isOnLock.lockInterruptibly();
-        try
-        {
-            // Reset the terminal and event queue
-            this.computer.getTerminal()
-                .reset();
-            this.interruptedEvent = false;
-            synchronized( this.queueLock )
-            {
-                this.eventQueue.clear();
-            }
-
-            // Init filesystem
-            if( (this.fileSystem = this.createFileSystem()) == null )
-            {
-                this.shutdown();
-                return;
-            }
-
-            // Init APIs
-            this.computer.getEnvironment()
-                .reset();
-            for( ILuaAPI api : this.apis )
-            {
-                api.startup();
-            }
-
-            // Init lua
-            if( (this.machine = this.createLuaMachine()) == null )
-            {
-                this.shutdown();
-                return;
-            }
-
-            // Initialisation has finished, so let's mark ourselves as on.
-            this.isOn = true;
-            this.computer.markChanged();
-        }
-        finally
-        {
-            this.isOnLock.unlock();
-        }
-
-        // Now actually start the computer, now that everything is set up.
-        this.resumeMachine( null, null );
-    }
-
-    private void shutdown() throws InterruptedException
-    {
-        this.isOnLock.lockInterruptibly();
-        try
-        {
-            this.isOn = false;
-            this.interruptedEvent = false;
-            synchronized( this.queueLock )
-            {
-                this.eventQueue.clear();
-            }
-
-            // Shutdown Lua machine
-            if( this.machine != null )
-            {
-                this.machine.close();
-                this.machine = null;
-            }
-
-            // Shutdown our APIs
-            for( ILuaAPI api : this.apis )
-            {
-                api.shutdown();
-            }
-            this.computer.getEnvironment()
-                .reset();
-
-            // Unload filesystem
-            if( this.fileSystem != null )
-            {
-                this.fileSystem.close();
-                this.fileSystem = null;
-            }
-
-            this.computer.getEnvironment()
-                .resetOutput();
-            this.computer.markChanged();
-        }
-        finally
-        {
-            this.isOnLock.unlock();
+            resumeMachine( event.name, event.args );
         }
     }
 
     private void displayFailure( String message, String extra )
     {
-        Terminal terminal = this.computer.getTerminal();
-        boolean colour = this.computer.getComputerEnvironment()
-            .isColour();
+        Terminal terminal = computer.getTerminal();
+        boolean colour = computer.getComputerEnvironment().isColour();
         terminal.reset();
 
         // Display our primary error message
-        if( colour )
-        {
-            terminal.setTextColour( 15 - Colour.RED.ordinal() );
-        }
+        if( colour ) terminal.setTextColour( 15 - Colour.RED.ordinal() );
         terminal.write( message );
 
         if( extra != null )
@@ -605,105 +644,27 @@ final class ComputerExecutor
 
         // And display our generic "CC may be installed incorrectly" message.
         terminal.setCursorPos( 0, terminal.getCursorY() + 1 );
-        if( colour )
-        {
-            terminal.setTextColour( 15 - Colour.WHITE.ordinal() );
-        }
+        if( colour ) terminal.setTextColour( 15 - Colour.WHITE.ordinal() );
         terminal.write( "ComputerCraft may be installed incorrectly" );
     }
 
-    private FileSystem createFileSystem()
+    private void resumeMachine( String event, Object[] args ) throws InterruptedException
     {
-        FileSystem filesystem = null;
-        try
-        {
-            filesystem = new FileSystem( "hdd", this.getRootMount() );
+        MachineResult result = machine.handleEvent( event, args );
+        interruptedEvent = result.isPause();
+        if( !result.isError() ) return;
 
-            IMount romMount = this.getRomMount();
-            if( romMount == null )
-            {
-                this.displayFailure( "Cannot mount ROM", null );
-                return null;
-            }
-
-            filesystem.mount( "rom", "rom", romMount );
-            return filesystem;
-        }
-        catch( FileSystemException e )
-        {
-            if( filesystem != null )
-            {
-                filesystem.close();
-            }
-            ComputerCraft.log.error( "Cannot mount computer filesystem", e );
-
-            this.displayFailure( "Cannot mount computer system", null );
-            return null;
-        }
-    }
-
-    private ILuaMachine createLuaMachine()
-    {
-        // Load the bios resource
-        InputStream biosStream = null;
-        try
-        {
-            biosStream = this.computer.getComputerEnvironment()
-                .createResourceFile( "computercraft", "lua/bios.lua" );
-        }
-        catch( Exception ignored )
-        {
-        }
-
-        if( biosStream == null )
-        {
-            this.displayFailure( "Error loading bios.lua", null );
-            return null;
-        }
-
-        // Create the lua machine
-        ILuaMachine machine = new CobaltLuaMachine( this.computer, this.timeout );
-
-        // Add the APIs. We unwrap them (yes, this is horrible) to get access to the underlying object.
-        for( ILuaAPI api : this.apis )
-        {
-            machine.addAPI( api instanceof ApiWrapper ? ((ApiWrapper) api).getDelegate() : api );
-        }
-
-        // Start the machine running the bios resource
-        MachineResult result = machine.loadBios( biosStream );
-        IoUtil.closeQuietly( biosStream );
-
-        if( result.isError() )
-        {
-            machine.close();
-            this.displayFailure( "Error loading bios.lua", result.getMessage() );
-            return null;
-        }
-
-        return machine;
-    }
-
-    private IWritableMount getRootMount()
-    {
-        if( this.rootMount == null )
-        {
-            this.rootMount = this.computer.getComputerEnvironment()
-                .createSaveDirMount( "computer/" + this.computer.assignID(), this.computer.getComputerEnvironment()
-                    .getComputerSpaceLimit() );
-        }
-        return this.rootMount;
-    }
-
-    private IMount getRomMount()
-    {
-        return this.computer.getComputerEnvironment()
-            .createResourceMount( "computercraft", "lua/rom" );
+        displayFailure( "Error running computer", result.getMessage() );
+        shutdown();
     }
 
     private enum StateCommand
     {
-        TURN_ON, SHUTDOWN, REBOOT, ABORT,
+        TURN_ON,
+        SHUTDOWN,
+        REBOOT,
+        ABORT,
+        ERROR,
     }
 
     private static final class Event

src/main/java/dan200/computercraft/core/computer/ComputerSide.java

@@ -3,27 +3,27 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
+import net.minecraft.util.math.Direction;
+
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 /**
- * A side on a computer. Unlike {@link Direction}, this is relative to the direction the computer is facing..
+ * A side on a computer. Unlike {@link Direction}, this is relative to the direction the computer is
+ * facing..
  */
 public enum ComputerSide
 {
-    BOTTOM( "bottom" ), TOP( "top" ), BACK( "back" ), FRONT( "front" ), RIGHT( "right" ), LEFT( "left" );
+    BOTTOM( "bottom" ),
+    TOP( "top" ),
+    BACK( "back" ),
+    FRONT( "front" ),
+    RIGHT( "right" ),
+    LEFT( "left" );
 
-    public static final String[] NAMES = new String[] {
-        "bottom",
-        "top",
-        "back",
-        "front",
-        "right",
-        "left"
-    };
+    public static final String[] NAMES = new String[] { "bottom", "top", "back", "front", "right", "left" };
 
     public static final int COUNT = 6;
 
@@ -47,10 +47,7 @@ public enum ComputerSide
     {
         for( ComputerSide side : VALUES )
         {
-            if( side.name.equalsIgnoreCase( name ) )
-            {
-                return side;
-            }
+            if( side.name.equalsIgnoreCase( name ) ) return side;
         }
 
         return null;
@@ -58,6 +55,6 @@ public enum ComputerSide
 
     public String getName()
     {
-        return this.name;
+        return name;
     }
 }

src/main/java/dan200/computercraft/core/computer/ComputerSystem.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.api.filesystem.IFileSystem;
@@ -44,6 +43,21 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
         return "computer";
     }
 
+    @Nullable
+    @Override
+    public IFileSystem getFileSystem()
+    {
+        FileSystem fs = environment.getFileSystem();
+        return fs == null ? null : fs.getMountWrapper();
+    }
+
+    @Nullable
+    @Override
+    public String getLabel()
+    {
+        return environment.getLabel();
+    }
+
     @Nonnull
     @Override
     public Map<String, IPeripheral> getAvailablePeripherals()
@@ -58,19 +72,4 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
     {
         return null;
     }
-
-    @Nullable
-    @Override
-    public IFileSystem getFileSystem()
-    {
-        FileSystem fs = this.environment.getFileSystem();
-        return fs == null ? null : fs.getMountWrapper();
-    }
-
-    @Nullable
-    @Override
-    public String getLabel()
-    {
-        return this.environment.getLabel();
-    }
 }

src/main/java/dan200/computercraft/core/computer/ComputerThread.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.ComputerCraft;
@@ -25,20 +24,24 @@ import static dan200.computercraft.core.computer.TimeoutState.TIMEOUT;
 /**
  * Responsible for running all tasks from a {@link Computer}.
  *
- * This is split into two components: the {@link TaskRunner}s, which pull an executor from the queue and execute it, and a single {@link Monitor} which
- * observes all runners and kills them if they have not been terminated by {@link TimeoutState#isSoftAborted()}.
+ * This is split into two components: the {@link TaskRunner}s, which pull an executor from the queue and execute it, and
+ * a single {@link Monitor} which observes all runners and kills them if they have not been terminated by
+ * {@link TimeoutState#isSoftAborted()}.
  *
- * Computers are executed using a priority system, with those who have spent less time executing having a higher priority than those hogging the thread.
- * This, combined with {@link TimeoutState#isPaused()} means we can reduce the risk of badly behaved computers stalling execution for everyone else.
+ * Computers are executed using a priority system, with those who have spent less time executing having a higher
+ * priority than those hogging the thread. This, combined with {@link TimeoutState#isPaused()} means we can reduce the
+ * risk of badly behaved computers stalling execution for everyone else.
  *
- * This is done using an implementation of Linux's Completely Fair Scheduler. When a computer executes, we compute what share of execution time it has used
- * (time executed/number of tasks). We then pick the computer who has the least "virtual execution time" (aka {@link ComputerExecutor#virtualRuntime}).
+ * This is done using an implementation of Linux's Completely Fair Scheduler. When a computer executes, we compute what
+ * share of execution time it has used (time executed/number of tasks). We then pick the computer who has the least
+ * "virtual execution time" (aka {@link ComputerExecutor#virtualRuntime}).
  *
- * When adding a computer to the queue, we make sure its "virtual runtime" is at least as big as the smallest runtime. This means that adding computers
- * which have slept a lot do not then have massive priority over everyone else. See {@link #queue(ComputerExecutor)} for how this is implemented.
+ * When adding a computer to the queue, we make sure its "virtual runtime" is at least as big as the smallest runtime.
+ * This means that adding computers which have slept a lot do not then have massive priority over everyone else. See
+ * {@link #queue(ComputerExecutor)} for how this is implemented.
  *
- * In reality, it's unlikely that more than a few computers are waiting to execute at once, so this will not have much effect unless you have a computer
- * hogging execution time. However, it is pretty effective in those situations.
+ * In reality, it's unlikely that more than a few computers are waiting to execute at once, so this will not have much
+ * effect unless you have a computer hogging execution time. However, it is pretty effective in those situations.
  *
  * @see TimeoutState For how hard timeouts are handled.
  * @see ComputerExecutor For how computers actually do execution.
@@ -55,15 +58,16 @@ public final class ComputerThread
     /**
      * The target latency between executing two tasks on a single machine.
      *
-     * An average tick takes 50ms, and so we ideally need to have handled a couple of events within that window in order to have a perceived low latency.
+     * An average tick takes 50ms, and so we ideally need to have handled a couple of events within that window in order
+     * to have a perceived low latency.
      */
     private static final long DEFAULT_LATENCY = TimeUnit.MILLISECONDS.toNanos( 50 );
 
     /**
      * The minimum value that {@link #DEFAULT_LATENCY} can have when scaled.
      *
-     * From statistics gathered on SwitchCraft, almost all machines will execute under 15ms, 75% under 1.5ms, with the mean being about 3ms. Most computers
-     * shouldn't be too impacted with having such a short period to execute in.
+     * From statistics gathered on SwitchCraft, almost all machines will execute under 15ms, 75% under 1.5ms, with the
+     * mean being about 3ms. Most computers shouldn't be too impacted with having such a short period to execute in.
      */
     private static final long DEFAULT_MIN_PERIOD = TimeUnit.MILLISECONDS.toNanos( 5 );
 
@@ -76,45 +80,48 @@ public final class ComputerThread
      * Lock used for modifications to the array of current threads.
      */
     private static final Object threadLock = new Object();
-    private static final ReentrantLock computerLock = new ReentrantLock();
-    private static final Condition hasWork = computerLock.newCondition();
-    /**
-     * Active queues to execute.
-     */
-    private static final TreeSet<ComputerExecutor> computerQueue = new TreeSet<>( ( a, b ) -> {
-        if( a == b )
-        {
-            return 0; // Should never happen, but let's be consistent here
-        }
 
-        long at = a.virtualRuntime, bt = b.virtualRuntime;
-        if( at == bt )
-        {
-            return Integer.compare( a.hashCode(), b.hashCode() );
-        }
-        return at < bt ? -1 : 1;
-    } );
-    private static final ThreadFactory monitorFactory = ThreadUtils.factory( "Computer-Monitor" );
-    private static final ThreadFactory runnerFactory = ThreadUtils.factory( "Computer-Runner" );
     /**
      * Whether the computer thread system is currently running.
      */
     private static volatile boolean running = false;
+
     /**
      * The current task manager.
      */
     private static Thread monitor;
+
     /**
      * The array of current runners, and their owning threads.
      */
     private static TaskRunner[] runners;
+
     private static long latency;
     private static long minPeriod;
+
+    private static final ReentrantLock computerLock = new ReentrantLock();
+
+    private static final Condition hasWork = computerLock.newCondition();
+
+    /**
+     * Active queues to execute.
+     */
+    private static final TreeSet<ComputerExecutor> computerQueue = new TreeSet<>( ( a, b ) -> {
+        if( a == b ) return 0; // Should never happen, but let's be consistent here
+
+        long at = a.virtualRuntime, bt = b.virtualRuntime;
+        if( at == bt ) return Integer.compare( a.hashCode(), b.hashCode() );
+        return at < bt ? -1 : 1;
+    } );
+
     /**
      * The minimum {@link ComputerExecutor#virtualRuntime} time on the tree.
      */
     private static long minimumVirtualRuntime = 0;
 
+    private static final ThreadFactory monitorFactory = ThreadUtils.factory( "Computer-Monitor" );
+    private static final ThreadFactory runnerFactory = ThreadUtils.factory( "Computer-Runner" );
+
     private ComputerThread() {}
 
     /**
@@ -144,20 +151,13 @@ public final class ComputerThread
                 if( runner == null || runner.owner == null || !runner.owner.isAlive() )
                 {
                     // Mark the old runner as dead, just in case.
-                    if( runner != null )
-                    {
-                        runner.running = false;
-                    }
+                    if( runner != null ) runner.running = false;
                     // And start a new runner
-                    runnerFactory.newThread( runners[i] = new TaskRunner() )
-                        .start();
+                    runnerFactory.newThread( runners[i] = new TaskRunner() ).start();
                 }
             }
 
-            if( monitor == null || !monitor.isAlive() )
-            {
-                (monitor = monitorFactory.newThread( new Monitor() )).start();
-            }
+            if( monitor == null || !monitor.isAlive() ) (monitor = monitorFactory.newThread( new Monitor() )).start();
         }
     }
 
@@ -173,16 +173,10 @@ public final class ComputerThread
             {
                 for( TaskRunner runner : runners )
                 {
-                    if( runner == null )
-                    {
-                        continue;
-                    }
+                    if( runner == null ) continue;
 
                     runner.running = false;
-                    if( runner.owner != null )
-                    {
-                        runner.owner.interrupt();
-                    }
+                    if( runner.owner != null ) runner.owner.interrupt();
                 }
             }
         }
@@ -201,7 +195,8 @@ public final class ComputerThread
     /**
      * Mark a computer as having work, enqueuing it on the thread.
      *
-     * You must be holding {@link ComputerExecutor}'s {@code queueLock} when calling this method - it should only be called from {@code enqueue}.
+     * You must be holding {@link ComputerExecutor}'s {@code queueLock} when calling this method - it should only
+     * be called from {@code enqueue}.
      *
      * @param executor The computer to execute work on.
      */
@@ -210,10 +205,7 @@ public final class ComputerThread
         computerLock.lock();
         try
         {
-            if( executor.onComputerQueue )
-            {
-                throw new IllegalStateException( "Cannot queue already queued executor" );
-            }
+            if( executor.onComputerQueue ) throw new IllegalStateException( "Cannot queue already queued executor" );
             executor.onComputerQueue = true;
 
             updateRuntimes( null );
@@ -247,8 +239,8 @@ public final class ComputerThread
 
 
     /**
-     * Update the {@link ComputerExecutor#virtualRuntime}s of all running tasks, and then update the {@link #minimumVirtualRuntime} based on the current
-     * tasks.
+     * Update the {@link ComputerExecutor#virtualRuntime}s of all running tasks, and then update the
+     * {@link #minimumVirtualRuntime} based on the current tasks.
      *
      * This is called before queueing tasks, to ensure that {@link #minimumVirtualRuntime} is up-to-date.
      *
@@ -259,10 +251,7 @@ public final class ComputerThread
         long minRuntime = Long.MAX_VALUE;
 
         // If we've a task on the queue, use that as our base time.
-        if( !computerQueue.isEmpty() )
-        {
-            minRuntime = computerQueue.first().virtualRuntime;
-        }
+        if( !computerQueue.isEmpty() ) minRuntime = computerQueue.first().virtualRuntime;
 
         // Update all the currently executing tasks
         long now = System.nanoTime();
@@ -272,15 +261,9 @@ public final class ComputerThread
         {
             for( TaskRunner runner : currentRunners )
             {
-                if( runner == null )
-                {
-                    continue;
-                }
+                if( runner == null ) continue;
                 ComputerExecutor executor = runner.currentExecutor.get();
-                if( executor == null )
-                {
-                    continue;
-                }
+                if( executor == null ) continue;
 
                 // We do two things here: first we update the task's virtual runtime based on when we
                 // last checked, and then we check the minimum.
@@ -301,6 +284,43 @@ public final class ComputerThread
         }
     }
 
+    /**
+     * Ensure the "currently working" state of the executor is reset, the timings are updated, and then requeue the
+     * executor if needed.
+     *
+     * @param runner   The runner this task was on.
+     * @param executor The executor to requeue
+     */
+    private static void afterWork( TaskRunner runner, ComputerExecutor executor )
+    {
+        // Clear the executor's thread.
+        Thread currentThread = executor.executingThread.getAndSet( null );
+        if( currentThread != runner.owner )
+        {
+            ComputerCraft.log.error(
+                "Expected computer #{} to be running on {}, but already running on {}. This is a SERIOUS bug, please report with your debug.log.",
+                executor.getComputer().getID(), runner.owner.getName(), currentThread == null ? "nothing" : currentThread.getName()
+            );
+        }
+
+        computerLock.lock();
+        try
+        {
+            updateRuntimes( executor );
+
+            // If we've no more tasks, just return.
+            if( !executor.afterWork() ) return;
+
+            // Otherwise, add to the queue, and signal any waiting workers.
+            computerQueue.add( executor );
+            hasWork.signal();
+        }
+        finally
+        {
+            computerLock.unlock();
+        }
+    }
+
     /**
      * The scaled period for a single task.
      *
@@ -316,47 +336,6 @@ public final class ComputerThread
         return count < LATENCY_MAX_TASKS ? latency / count : minPeriod;
     }
 
-    /**
-     * Ensure the "currently working" state of the executor is reset, the timings are updated, and then requeue the executor if needed.
-     *
-     * @param runner   The runner this task was on.
-     * @param executor The executor to requeue
-     */
-    private static void afterWork( TaskRunner runner, ComputerExecutor executor )
-    {
-        // Clear the executor's thread.
-        Thread currentThread = executor.executingThread.getAndSet( null );
-        if( currentThread != runner.owner )
-        {
-            ComputerCraft.log.error(
-                "Expected computer #{} to be running on {}, but already running on {}. This is a SERIOUS bug, please report with your debug.log.",
-                executor.getComputer()
-                    .getID(),
-                runner.owner.getName(),
-                currentThread == null ? "nothing" : currentThread.getName() );
-        }
-
-        computerLock.lock();
-        try
-        {
-            updateRuntimes( executor );
-
-            // If we've no more tasks, just return.
-            if( !executor.afterWork() )
-            {
-                return;
-            }
-
-            // Otherwise, add to the queue, and signal any waiting workers.
-            computerQueue.add( executor );
-            hasWork.signal();
-        }
-        finally
-        {
-            computerLock.unlock();
-        }
-    }
-
     /**
      * Determine if the thread has computers queued up.
      *
@@ -367,40 +346,9 @@ public final class ComputerThread
         return !computerQueue.isEmpty();
     }
 
-    private static void timeoutTask( ComputerExecutor executor, Thread thread, long time )
-    {
-        if( !ComputerCraft.logComputerErrors )
-        {
-            return;
-        }
-
-        StringBuilder builder = new StringBuilder().append( "Terminating computer #" )
-            .append( executor.getComputer()
-                .getID() )
-            .append( " due to timeout (running for " )
-            .append( time * 1e-9 )
-            .append( " seconds). This is NOT a bug, but may mean a computer is misbehaving. " )
-            .append( thread.getName() )
-            .append( " is currently " )
-            .append( thread.getState() );
-        Object blocking = LockSupport.getBlocker( thread );
-        if( blocking != null )
-        {
-            builder.append( "\n  on " )
-                .append( blocking );
-        }
-
-        for( StackTraceElement element : thread.getStackTrace() )
-        {
-            builder.append( "\n  at " )
-                .append( element );
-        }
-
-        ComputerCraft.log.warn( builder.toString() );
-    }
-
     /**
-     * Observes all currently active {@link TaskRunner}s and terminates their tasks once they have exceeded the hard abort limit.
+     * Observes all currently active {@link TaskRunner}s and terminates their tasks once they have exceeded the hard
+     * abort limit.
      *
      * @see TimeoutState
      */
@@ -424,37 +372,24 @@ public final class ComputerThread
                             // If we've no runner, skip.
                             if( runner == null || runner.owner == null || !runner.owner.isAlive() )
                             {
-                                if( !running )
-                                {
-                                    continue;
-                                }
+                                if( !running ) continue;
 
                                 // Mark the old runner as dead and start a new one.
                                 ComputerCraft.log.warn( "Previous runner ({}) has crashed, restarting!",
                                     runner != null && runner.owner != null ? runner.owner.getName() : runner );
-                                if( runner != null )
-                                {
-                                    runner.running = false;
-                                }
-                                runnerFactory.newThread( runners[i] = new TaskRunner() )
-                                    .start();
+                                if( runner != null ) runner.running = false;
+                                runnerFactory.newThread( runners[i] = new TaskRunner() ).start();
                             }
 
                             // If the runner has no work, skip
                             ComputerExecutor executor = runner.currentExecutor.get();
-                            if( executor == null )
-                            {
-                                continue;
-                            }
+                            if( executor == null ) continue;
 
                             // If we're still within normal execution times (TIMEOUT) or soft abort (ABORT_TIMEOUT),
                             // then we can let the Lua machine do its work.
                             long afterStart = executor.timeout.nanoCumulative();
                             long afterHardAbort = afterStart - TIMEOUT - ABORT_TIMEOUT;
-                            if( afterHardAbort < 0 )
-                            {
-                                continue;
-                            }
+                            if( afterHardAbort < 0 ) continue;
 
                             // Set the hard abort flag.
                             executor.timeout.hardAbort();
@@ -469,17 +404,13 @@ public final class ComputerThread
                                 runner.owner.interrupt();
 
                                 ComputerExecutor thisExecutor = runner.currentExecutor.getAndSet( null );
-                                if( thisExecutor != null )
-                                {
-                                    afterWork( runner, executor );
-                                }
+                                if( thisExecutor != null ) afterWork( runner, executor );
 
                                 synchronized( threadLock )
                                 {
                                     if( running && runners.length > i && runners[i] == runner )
                                     {
-                                        runnerFactory.newThread( currentRunners[i] = new TaskRunner() )
-                                            .start();
+                                        runnerFactory.newThread( currentRunners[i] = new TaskRunner() ).start();
                                     }
                                 }
                             }
@@ -503,22 +434,24 @@ public final class ComputerThread
     /**
      * Pulls tasks from the {@link #computerQueue} queue and runs them.
      *
-     * This is responsible for running the {@link ComputerExecutor#work()}, {@link ComputerExecutor#beforeWork()} and {@link ComputerExecutor#afterWork()}
-     * functions. Everything else is either handled by the executor, timeout state or monitor.
+     * This is responsible for running the {@link ComputerExecutor#work()}, {@link ComputerExecutor#beforeWork()} and
+     * {@link ComputerExecutor#afterWork()} functions. Everything else is either handled by the executor, timeout
+     * state or monitor.
      */
     private static final class TaskRunner implements Runnable
     {
-        final AtomicReference<ComputerExecutor> currentExecutor = new AtomicReference<>();
         Thread owner;
         volatile boolean running = true;
 
+        final AtomicReference<ComputerExecutor> currentExecutor = new AtomicReference<>();
+
         @Override
         public void run()
         {
-            this.owner = Thread.currentThread();
+            owner = Thread.currentThread();
 
             tasks:
-            while( this.running && ComputerThread.running )
+            while( running && ComputerThread.running )
             {
                 // Wait for an active queue to execute
                 ComputerExecutor executor;
@@ -527,10 +460,7 @@ public final class ComputerThread
                     computerLock.lockInterruptibly();
                     try
                     {
-                        while( computerQueue.isEmpty() )
-                        {
-                            hasWork.await();
-                        }
+                        while( computerQueue.isEmpty() ) hasWork.await();
                         executor = computerQueue.pollFirst();
                         assert executor != null : "hasWork should ensure we never receive null work";
                     }
@@ -548,16 +478,15 @@ public final class ComputerThread
 
                 // If we're trying to executing some task on this computer while someone else is doing work, something
                 // is seriously wrong.
-                while( !executor.executingThread.compareAndSet( null, this.owner ) )
+                while( !executor.executingThread.compareAndSet( null, owner ) )
                 {
                     Thread existing = executor.executingThread.get();
                     if( existing != null )
                     {
                         ComputerCraft.log.error(
                             "Trying to run computer #{} on thread {}, but already running on {}. This is a SERIOUS bug, please report with your debug.log.",
-                            executor.getComputer()
-                                .getID(), this.owner.getName(),
-                            existing.getName() );
+                            executor.getComputer().getID(), owner.getName(), existing.getName()
+                        );
                         continue tasks;
                     }
                 }
@@ -567,7 +496,7 @@ public final class ComputerThread
 
                 // And then set the current executor. It's important to do it afterwards, as otherwise we introduce
                 // race conditions with the monitor.
-                this.currentExecutor.set( executor );
+                currentExecutor.set( executor );
 
                 // Execute the task
                 try
@@ -576,18 +505,38 @@ public final class ComputerThread
                 }
                 catch( Exception | LinkageError | VirtualMachineError e )
                 {
-                    ComputerCraft.log.error( "Error running task on computer #" + executor.getComputer()
-                        .getID(), e );
+                    ComputerCraft.log.error( "Error running task on computer #" + executor.getComputer().getID(), e );
+                    // Tear down the computer immediately. There's no guarantee it's well behaved from now on.
+                    executor.fastFail();
                 }
                 finally
                 {
-                    ComputerExecutor thisExecutor = this.currentExecutor.getAndSet( null );
-                    if( thisExecutor != null )
-                    {
-                        afterWork( this, executor );
-                    }
+                    ComputerExecutor thisExecutor = currentExecutor.getAndSet( null );
+                    if( thisExecutor != null ) afterWork( this, executor );
                 }
             }
         }
     }
+
+    private static void timeoutTask( ComputerExecutor executor, Thread thread, long time )
+    {
+        if( !ComputerCraft.logComputerErrors ) return;
+
+        StringBuilder builder = new StringBuilder()
+            .append( "Terminating computer #" ).append( executor.getComputer().getID() )
+            .append( " due to timeout (running for " ).append( time * 1e-9 )
+            .append( " seconds). This is NOT a bug, but may mean a computer is misbehaving. " )
+            .append( thread.getName() )
+            .append( " is currently " )
+            .append( thread.getState() );
+        Object blocking = LockSupport.getBlocker( thread );
+        if( blocking != null ) builder.append( "\n  on " ).append( blocking );
+
+        for( StackTraceElement element : thread.getStackTrace() )
+        {
+            builder.append( "\n  at " ).append( element );
+        }
+
+        ComputerCraft.log.warn( builder.toString() );
+    }
 }

src/main/java/dan200/computercraft/core/computer/Environment.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.api.lua.ILuaAPI;
@@ -43,17 +42,22 @@ import java.util.Iterator;
 public final class Environment implements IAPIEnvironment
 {
     private final Computer computer;
+
+    private boolean internalOutputChanged = false;
     private final int[] internalOutput = new int[ComputerSide.COUNT];
     private final int[] internalBundledOutput = new int[ComputerSide.COUNT];
+
     private final int[] externalOutput = new int[ComputerSide.COUNT];
     private final int[] externalBundledOutput = new int[ComputerSide.COUNT];
+
+    private boolean inputChanged = false;
     private final int[] input = new int[ComputerSide.COUNT];
     private final int[] bundledInput = new int[ComputerSide.COUNT];
+
     private final IPeripheral[] peripherals = new IPeripheral[ComputerSide.COUNT];
-    private final Int2ObjectMap<Timer> timers = new Int2ObjectOpenHashMap<>();
-    private boolean internalOutputChanged = false;
-    private boolean inputChanged = false;
     private IPeripheralChangeListener peripheralListener = null;
+
+    private final Int2ObjectMap<Timer> timers = new Int2ObjectOpenHashMap<>();
     private int nextTimerToken = 0;
 
     Environment( Computer computer )
@@ -64,64 +68,76 @@ public final class Environment implements IAPIEnvironment
     @Override
     public int getComputerID()
     {
-        return this.computer.assignID();
+        return computer.assignID();
     }
 
     @Nonnull
     @Override
     public IComputerEnvironment getComputerEnvironment()
     {
-        return this.computer.getComputerEnvironment();
+        return computer.getComputerEnvironment();
     }
 
     @Nonnull
     @Override
     public IWorkMonitor getMainThreadMonitor()
     {
-        return this.computer.getMainThreadMonitor();
+        return computer.getMainThreadMonitor();
     }
 
     @Nonnull
     @Override
     public Terminal getTerminal()
     {
-        return this.computer.getTerminal();
+        return computer.getTerminal();
     }
 
     @Override
     public FileSystem getFileSystem()
     {
-        return this.computer.getFileSystem();
+        return computer.getFileSystem();
     }
 
     @Override
     public void shutdown()
     {
-        this.computer.shutdown();
+        computer.shutdown();
     }
 
     @Override
     public void reboot()
     {
-        this.computer.reboot();
+        computer.reboot();
     }
 
     @Override
     public void queueEvent( String event, Object... args )
     {
-        this.computer.queueEvent( event, args );
+        computer.queueEvent( event, args );
+    }
+
+    @Override
+    public int getInput( ComputerSide side )
+    {
+        return input[side.ordinal()];
+    }
+
+    @Override
+    public int getBundledInput( ComputerSide side )
+    {
+        return bundledInput[side.ordinal()];
     }
 
     @Override
     public void setOutput( ComputerSide side, int output )
     {
         int index = side.ordinal();
-        synchronized( this.internalOutput )
+        synchronized( internalOutput )
         {
-            if( this.internalOutput[index] != output )
+            if( internalOutput[index] != output )
             {
-                this.internalOutput[index] = output;
-                this.internalOutputChanged = true;
+                internalOutput[index] = output;
+                internalOutputChanged = true;
             }
         }
     }
@@ -129,28 +145,22 @@ public final class Environment implements IAPIEnvironment
     @Override
     public int getOutput( ComputerSide side )
     {
-        synchronized( this.internalOutput )
+        synchronized( internalOutput )
         {
-            return this.computer.isOn() ? this.internalOutput[side.ordinal()] : 0;
+            return computer.isOn() ? internalOutput[side.ordinal()] : 0;
         }
     }
 
-    @Override
-    public int getInput( ComputerSide side )
-    {
-        return this.input[side.ordinal()];
-    }
-
     @Override
     public void setBundledOutput( ComputerSide side, int output )
     {
         int index = side.ordinal();
-        synchronized( this.internalOutput )
+        synchronized( internalOutput )
         {
-            if( this.internalBundledOutput[index] != output )
+            if( internalBundledOutput[index] != output )
             {
-                this.internalBundledOutput[index] = output;
-                this.internalOutputChanged = true;
+                internalBundledOutput[index] = output;
+                internalOutputChanged = true;
             }
         }
     }
@@ -158,100 +168,39 @@ public final class Environment implements IAPIEnvironment
     @Override
     public int getBundledOutput( ComputerSide side )
     {
-        synchronized( this.internalOutput )
+        synchronized( internalOutput )
         {
-            return this.computer.isOn() ? this.internalBundledOutput[side.ordinal()] : 0;
+            return computer.isOn() ? internalBundledOutput[side.ordinal()] : 0;
         }
     }
 
-    @Override
-    public int getBundledInput( ComputerSide side )
-    {
-        return this.bundledInput[side.ordinal()];
-    }
-
-    @Override
-    public void setPeripheralChangeListener( IPeripheralChangeListener listener )
-    {
-        synchronized( this.peripherals )
-        {
-            this.peripheralListener = listener;
-        }
-    }
-
-    @Override
-    public IPeripheral getPeripheral( ComputerSide side )
-    {
-        synchronized( this.peripherals )
-        {
-            return this.peripherals[side.ordinal()];
-        }
-    }
-
-    @Override
-    public String getLabel()
-    {
-        return this.computer.getLabel();
-    }
-
-    @Override
-    public void setLabel( String label )
-    {
-        this.computer.setLabel( label );
-    }
-
-    @Override
-    public int startTimer( long ticks )
-    {
-        synchronized( this.timers )
-        {
-            this.timers.put( this.nextTimerToken, new Timer( ticks ) );
-            return this.nextTimerToken++;
-        }
-    }
-
-    @Override
-    public void cancelTimer( int id )
-    {
-        synchronized( this.timers )
-        {
-            this.timers.remove( id );
-        }
-    }
-
-    @Override
-    public void addTrackingChange( @Nonnull TrackingField field, long change )
-    {
-        Tracking.addValue( this.computer, field, change );
-    }
-
     public int getExternalRedstoneOutput( ComputerSide side )
     {
-        return this.computer.isOn() ? this.externalOutput[side.ordinal()] : 0;
+        return computer.isOn() ? externalOutput[side.ordinal()] : 0;
     }
 
     public int getExternalBundledRedstoneOutput( ComputerSide side )
     {
-        return this.computer.isOn() ? this.externalBundledOutput[side.ordinal()] : 0;
+        return computer.isOn() ? externalBundledOutput[side.ordinal()] : 0;
     }
 
     public void setRedstoneInput( ComputerSide side, int level )
     {
         int index = side.ordinal();
-        if( this.input[index] != level )
+        if( input[index] != level )
         {
-            this.input[index] = level;
-            this.inputChanged = true;
+            input[index] = level;
+            inputChanged = true;
         }
     }
 
     public void setBundledRedstoneInput( ComputerSide side, int combination )
     {
         int index = side.ordinal();
-        if( this.bundledInput[index] != combination )
+        if( bundledInput[index] != combination )
         {
-            this.bundledInput[index] = combination;
-            this.inputChanged = true;
+            bundledInput[index] = combination;
+            inputChanged = true;
         }
     }
 
@@ -263,9 +212,9 @@ public final class Environment implements IAPIEnvironment
      */
     void reset()
     {
-        synchronized( this.timers )
+        synchronized( timers )
         {
-            this.timers.clear();
+            timers.clear();
         }
     }
 
@@ -274,17 +223,16 @@ public final class Environment implements IAPIEnvironment
      */
     void tick()
     {
-        if( this.inputChanged )
+        if( inputChanged )
         {
-            this.inputChanged = false;
-            this.queueEvent( "redstone" );
+            inputChanged = false;
+            queueEvent( "redstone" );
         }
 
-        synchronized( this.timers )
+        synchronized( timers )
         {
             // Countdown all of our active timers
-            Iterator<Int2ObjectMap.Entry<Timer>> it = this.timers.int2ObjectEntrySet()
-                .iterator();
+            Iterator<Int2ObjectMap.Entry<Timer>> it = timers.int2ObjectEntrySet().iterator();
             while( it.hasNext() )
             {
                 Int2ObjectMap.Entry<Timer> entry = it.next();
@@ -293,7 +241,7 @@ public final class Environment implements IAPIEnvironment
                 if( timer.ticksLeft <= 0 )
                 {
                     // Queue the "timer" event
-                    this.queueEvent( TIMER_EVENT, entry.getIntKey() );
+                    queueEvent( TIMER_EVENT, entry.getIntKey() );
                     it.remove();
                 }
             }
@@ -308,31 +256,28 @@ public final class Environment implements IAPIEnvironment
     boolean updateOutput()
     {
         // Mark output as changed if the internal redstone has changed
-        synchronized( this.internalOutput )
+        synchronized( internalOutput )
         {
-            if( !this.internalOutputChanged )
-            {
-                return false;
-            }
+            if( !internalOutputChanged ) return false;
 
             boolean changed = false;
 
             for( int i = 0; i < ComputerSide.COUNT; i++ )
             {
-                if( this.externalOutput[i] != this.internalOutput[i] )
+                if( externalOutput[i] != internalOutput[i] )
                 {
-                    this.externalOutput[i] = this.internalOutput[i];
+                    externalOutput[i] = internalOutput[i];
                     changed = true;
                 }
 
-                if( this.externalBundledOutput[i] != this.internalBundledOutput[i] )
+                if( externalBundledOutput[i] != internalBundledOutput[i] )
                 {
-                    this.externalBundledOutput[i] = this.internalBundledOutput[i];
+                    externalBundledOutput[i] = internalBundledOutput[i];
                     changed = true;
                 }
             }
 
-            this.internalOutputChanged = false;
+            internalOutputChanged = false;
 
             return changed;
         }
@@ -341,31 +286,85 @@ public final class Environment implements IAPIEnvironment
     void resetOutput()
     {
         // Reset redstone output
-        synchronized( this.internalOutput )
+        synchronized( internalOutput )
         {
-            Arrays.fill( this.internalOutput, 0 );
-            Arrays.fill( this.internalBundledOutput, 0 );
-            this.internalOutputChanged = true;
+            Arrays.fill( internalOutput, 0 );
+            Arrays.fill( internalBundledOutput, 0 );
+            internalOutputChanged = true;
+        }
+    }
+
+    @Override
+    public IPeripheral getPeripheral( ComputerSide side )
+    {
+        synchronized( peripherals )
+        {
+            return peripherals[side.ordinal()];
         }
     }
 
     public void setPeripheral( ComputerSide side, IPeripheral peripheral )
     {
-        synchronized( this.peripherals )
+        synchronized( peripherals )
         {
             int index = side.ordinal();
-            IPeripheral existing = this.peripherals[index];
-            if( (existing == null && peripheral != null) || (existing != null && peripheral == null) || (existing != null && !existing.equals( peripheral )) )
+            IPeripheral existing = peripherals[index];
+            if( (existing == null && peripheral != null) ||
+                (existing != null && peripheral == null) ||
+                (existing != null && !existing.equals( peripheral )) )
             {
-                this.peripherals[index] = peripheral;
-                if( this.peripheralListener != null )
-                {
-                    this.peripheralListener.onPeripheralChanged( side, peripheral );
-                }
+                peripherals[index] = peripheral;
+                if( peripheralListener != null ) peripheralListener.onPeripheralChanged( side, peripheral );
             }
         }
     }
 
+    @Override
+    public void setPeripheralChangeListener( IPeripheralChangeListener listener )
+    {
+        synchronized( peripherals )
+        {
+            peripheralListener = listener;
+        }
+    }
+
+    @Override
+    public String getLabel()
+    {
+        return computer.getLabel();
+    }
+
+    @Override
+    public void setLabel( String label )
+    {
+        computer.setLabel( label );
+    }
+
+    @Override
+    public int startTimer( long ticks )
+    {
+        synchronized( timers )
+        {
+            timers.put( nextTimerToken, new Timer( ticks ) );
+            return nextTimerToken++;
+        }
+    }
+
+    @Override
+    public void cancelTimer( int id )
+    {
+        synchronized( timers )
+        {
+            timers.remove( id );
+        }
+    }
+
+    @Override
+    public void addTrackingChange( @Nonnull TrackingField field, long change )
+    {
+        Tracking.addValue( computer, field, change );
+    }
+
     private static class Timer
     {
         long ticksLeft;

src/main/java/dan200/computercraft/core/computer/IComputerEnvironment.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.api.filesystem.IMount;

src/main/java/dan200/computercraft/core/computer/MainThread.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.ComputerCraft;
@@ -15,16 +14,17 @@ import java.util.TreeSet;
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
- * Runs tasks on the main (server) thread, ticks {@link MainThreadExecutor}s, and limits how much time is used this tick.
+ * Runs tasks on the main (server) thread, ticks {@link MainThreadExecutor}s, and limits how much time is used this
+ * tick.
  *
- * Similar to {@link MainThreadExecutor}, the {@link MainThread} can be in one of three states: cool, hot and cooling. However, the implementation here is a
- * little different:
+ * Similar to {@link MainThreadExecutor}, the {@link MainThread} can be in one of three states: cool, hot and cooling.
+ * However, the implementation here is a little different:
  *
- * {@link MainThread} starts cool, and runs as many tasks as it can in the current {@link #budget}ns. Any external tasks (those run by tile entities,
- * etc...) will also consume the budget
+ * {@link MainThread} starts cool, and runs as many tasks as it can in the current {@link #budget}ns. Any external tasks
+ * (those run by tile entities, etc...) will also consume the budget
  *
- * Next tick, we put {@link ComputerCraft#maxMainGlobalTime} into our budget (and clamp it to that value to). If we're still over budget, then we should not
- * execute <em>any</em> work (either as part of {@link MainThread} or externally).
+ * Next tick, we put {@link ComputerCraft#maxMainGlobalTime} into our budget (and clamp it to that value to). If we're
+ * still over budget, then we should not execute <em>any</em> work (either as part of {@link MainThread} or externally).
  */
 public final class MainThread
 {
@@ -40,16 +40,10 @@ public final class MainThread
      * The queue of {@link MainThreadExecutor}s with tasks to perform.
      */
     private static final TreeSet<MainThreadExecutor> executors = new TreeSet<>( ( a, b ) -> {
-        if( a == b )
-        {
-            return 0; // Should never happen, but let's be consistent here
-        }
+        if( a == b ) return 0; // Should never happen, but let's be consistent here
 
         long at = a.virtualTime, bt = b.virtualTime;
-        if( at == bt )
-        {
-            return Integer.compare( a.hashCode(), b.hashCode() );
-        }
+        if( at == bt ) return Integer.compare( a.hashCode(), b.hashCode() );
         return at < bt ? -1 : 1;
     } );
 
@@ -62,7 +56,8 @@ public final class MainThread
     private static final HashSet<MainThreadExecutor> cooling = new HashSet<>();
 
     /**
-     * The current tick number. This is used by {@link MainThreadExecutor} to determine when to reset its own time counter.
+     * The current tick number. This is used by {@link MainThreadExecutor} to determine when to reset its own time
+     * counter.
      *
      * @see #currentTick()
      */
@@ -93,10 +88,7 @@ public final class MainThread
     {
         synchronized( executors )
         {
-            if( executor.onQueue )
-            {
-                throw new IllegalStateException( "Cannot queue already queued executor" );
-            }
+            if( executor.onQueue ) throw new IllegalStateException( "Cannot queue already queued executor" );
             executor.onQueue = true;
             executor.updateTime();
 
@@ -105,10 +97,7 @@ public final class MainThread
             long newRuntime = minimumTime;
 
             // Slow down new computers a little bit.
-            if( executor.virtualTime == 0 )
-            {
-                newRuntime += ComputerCraft.maxMainComputerTime;
-            }
+            if( executor.virtualTime == 0 ) newRuntime += ComputerCraft.maxMainComputerTime;
 
             executor.virtualTime = Math.max( newRuntime, executor.virtualTime );
 
@@ -121,6 +110,11 @@ public final class MainThread
         cooling.add( executor );
     }
 
+    static void consumeTime( long time )
+    {
+        budget -= time;
+    }
+
     static boolean canExecute()
     {
         return canExecute;
@@ -145,10 +139,7 @@ public final class MainThread
         // Cool down any warm computers.
         cooling.removeIf( MainThreadExecutor::tickCooling );
 
-        if( !canExecute )
-        {
-            return;
-        }
+        if( !canExecute ) return;
 
         // Run until we meet the deadline.
         long start = System.nanoTime();
@@ -160,10 +151,7 @@ public final class MainThread
             {
                 executor = executors.pollFirst();
             }
-            if( executor == null )
-            {
-                break;
-            }
+            if( executor == null ) break;
 
             long taskStart = System.nanoTime();
             executor.execute();
@@ -171,10 +159,7 @@ public final class MainThread
             long taskStop = System.nanoTime();
             synchronized( executors )
             {
-                if( executor.afterExecute( taskStop - taskStart ) )
-                {
-                    executors.add( executor );
-                }
+                if( executor.afterExecute( taskStop - taskStart ) ) executors.add( executor );
 
                 // Compute the new minimum time (including the next task on the queue too). Note that this may also include
                 // time spent in external tasks.
@@ -182,28 +167,17 @@ public final class MainThread
                 if( !executors.isEmpty() )
                 {
                     MainThreadExecutor next = executors.first();
-                    if( next.virtualTime < newMinimum )
-                    {
-                        newMinimum = next.virtualTime;
-                    }
+                    if( next.virtualTime < newMinimum ) newMinimum = next.virtualTime;
                 }
                 minimumTime = Math.max( minimumTime, newMinimum );
             }
 
-            if( taskStop >= deadline )
-            {
-                break;
-            }
+            if( taskStop >= deadline ) break;
         }
 
         consumeTime( System.nanoTime() - start );
     }
 
-    static void consumeTime( long time )
-    {
-        budget -= time;
-    }
-
     public static void reset()
     {
         currentTick = 0;

src/main/java/dan200/computercraft/core/computer/MainThreadExecutor.java

@@ -3,13 +3,13 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.shared.turtle.core.TurtleBrain;
+import net.minecraft.block.entity.BlockEntity;
 
 import javax.annotation.Nonnull;
 import java.util.ArrayDeque;
@@ -17,28 +17,32 @@ import java.util.Queue;
 import java.util.concurrent.TimeUnit;
 
 /**
- * Keeps track of tasks that a {@link Computer} should run on the main thread and how long that has been spent executing them.
+ * Keeps track of tasks that a {@link Computer} should run on the main thread and how long that has been spent executing
+ * them.
  *
- * This provides rate-limiting mechanism for tasks enqueued with {@link Computer#queueMainThread(Runnable)}, but also those run elsewhere (such as during
- * the turtle's tick - see {@link TurtleBrain#update()}). In order to handle this, the executor goes through three stages:
+ * This provides rate-limiting mechanism for tasks enqueued with {@link Computer#queueMainThread(Runnable)}, but also
+ * those run elsewhere (such as during the turtle's tick - see {@link TurtleBrain#update()}). In order to handle this,
+ * the executor goes through three stages:
  *
- * When {@link State#COOL}, the computer is allocated {@link ComputerCraft#maxMainComputerTime}ns to execute any work this tick. At the beginning of the
- * tick, we execute as many {@link MainThread} tasks as possible, until our time-frame or the global time frame has expired.
+ * When {@link State#COOL}, the computer is allocated {@link ComputerCraft#maxMainComputerTime}ns to execute any work
+ * this tick. At the beginning of the tick, we execute as many {@link MainThread} tasks as possible, until our
+ * time-frame or the global time frame has expired.
  *
- * Then, when other objects (such as {@link TileEntity}) are ticked, we update how much time we've used using {@link IWorkMonitor#trackWork(long,
- * TimeUnit)}.
+ * Then, when other objects (such as {@link BlockEntity}) are ticked, we update how much time we've used using
+ * {@link IWorkMonitor#trackWork(long, TimeUnit)}.
  *
- * Now, if anywhere during this period, we use more than our allocated time slice, the executor is marked as {@link State#HOT}. This means it will no longer
- * be able to execute {@link MainThread} tasks (though will still execute tile entity tasks, in order to prevent the main thread from exhausting work every
- * tick).
+ * Now, if anywhere during this period, we use more than our allocated time slice, the executor is marked as
+ * {@link State#HOT}. This means it will no longer be able to execute {@link MainThread} tasks (though will still
+ * execute tile entity tasks, in order to prevent the main thread from exhausting work every tick).
  *
- * At the beginning of the next tick, we increment the budget e by {@link ComputerCraft#maxMainComputerTime} and any {@link State#HOT} executors are marked
- * as {@link State#COOLING}. They will remain cooling until their budget is fully replenished (is equal to {@link ComputerCraft#maxMainComputerTime}). Note,
- * this is different to {@link MainThread}, which allows running when it has any budget left. When cooling, <em>no</em> tasks are executed - be they on the
- * tile entity or main thread.
+ * At the beginning of the next tick, we increment the budget e by {@link ComputerCraft#maxMainComputerTime} and any
+ * {@link State#HOT} executors are marked as {@link State#COOLING}. They will remain cooling until their budget is
+ * fully replenished (is equal to {@link ComputerCraft#maxMainComputerTime}). Note, this is different to
+ * {@link MainThread}, which allows running when it has any budget left. When cooling, <em>no</em> tasks are executed -
+ * be they on the tile entity or main thread.
  *
- * This mechanism means that, on average, computers will use at most {@link ComputerCraft#maxMainComputerTime}ns per second, but one task source will not
- * prevent others from executing.
+ * This mechanism means that, on average, computers will use at most {@link ComputerCraft#maxMainComputerTime}ns per
+ * second, but one task source will not prevent others from executing.
  *
  * @see MainThread
  * @see IWorkMonitor
@@ -55,8 +59,8 @@ final class MainThreadExecutor implements IWorkMonitor
     private final Computer computer;
 
     /**
-     * A lock used for any changes to {@link #tasks}, or {@link #onQueue}. This will be used on the main thread, so locks should be kept as brief as
-     * possible.
+     * A lock used for any changes to {@link #tasks}, or {@link #onQueue}. This will be
+     * used on the main thread, so locks should be kept as brief as possible.
      */
     private final Object queueLock = new Object();
 
@@ -77,7 +81,7 @@ final class MainThreadExecutor implements IWorkMonitor
      * @see #afterExecute(long)
      */
     volatile boolean onQueue;
-    long virtualTime;
+
     /**
      * The remaining budgeted time for this tick. This may be negative, in the case that we've gone over budget.
      *
@@ -85,6 +89,7 @@ final class MainThreadExecutor implements IWorkMonitor
      * @see #consumeTime(long)
      */
     private long budget = 0;
+
     /**
      * The last tick that {@link #budget} was updated.
      *
@@ -92,14 +97,18 @@ final class MainThreadExecutor implements IWorkMonitor
      * @see #consumeTime(long)
      */
     private int currentTick = -1;
+
     /**
      * The current state of this executor.
      *
      * @see #canWork()
      */
     private State state = State.COOL;
+
     private long pendingTime;
 
+    long virtualTime;
+
     MainThreadExecutor( Computer computer )
     {
         this.computer = computer;
@@ -113,37 +122,25 @@ final class MainThreadExecutor implements IWorkMonitor
      */
     boolean enqueue( Runnable runnable )
     {
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
-            if( this.tasks.size() >= MAX_TASKS || !this.tasks.offer( runnable ) )
-            {
-                return false;
-            }
-            if( !this.onQueue && this.state == State.COOL )
-            {
-                MainThread.queue( this, true );
-            }
+            if( tasks.size() >= MAX_TASKS || !tasks.offer( runnable ) ) return false;
+            if( !onQueue && state == State.COOL ) MainThread.queue( this, true );
             return true;
         }
     }
 
     void execute()
     {
-        if( this.state != State.COOL )
-        {
-            return;
-        }
+        if( state != State.COOL ) return;
 
         Runnable task;
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
-            task = this.tasks.poll();
+            task = tasks.poll();
         }
 
-        if( task != null )
-        {
-            task.run();
-        }
+        if( task != null ) task.run();
     }
 
     /**
@@ -154,54 +151,17 @@ final class MainThreadExecutor implements IWorkMonitor
      */
     boolean afterExecute( long time )
     {
-        this.consumeTime( time );
+        consumeTime( time );
 
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
-            this.virtualTime += time;
-            this.updateTime();
-            if( this.state != State.COOL || this.tasks.isEmpty() )
-            {
-                return this.onQueue = false;
-            }
+            virtualTime += time;
+            updateTime();
+            if( state != State.COOL || tasks.isEmpty() ) return onQueue = false;
             return true;
         }
     }
 
-    private void consumeTime( long time )
-    {
-        Tracking.addServerTiming( this.computer, time );
-
-        // Reset the budget if moving onto a new tick. We know this is safe, as this will only have happened if
-        // #tickCooling() isn't called, and so we didn't overrun the previous tick.
-        if( this.currentTick != MainThread.currentTick() )
-        {
-            this.currentTick = MainThread.currentTick();
-            this.budget = ComputerCraft.maxMainComputerTime;
-        }
-
-        this.budget -= time;
-
-        // If we've gone over our limit, mark us as having to cool down.
-        if( this.budget < 0 && this.state == State.COOL )
-        {
-            this.state = State.HOT;
-            MainThread.cooling( this );
-        }
-    }
-
-    void updateTime()
-    {
-        this.virtualTime += this.pendingTime;
-        this.pendingTime = 0;
-    }
-
-    @Override
-    public boolean shouldWork()
-    {
-        return this.state == State.COOL && MainThread.canExecute();
-    }
-
     /**
      * Whether we should execute "external" tasks (ones not part of {@link #tasks}).
      *
@@ -210,22 +170,50 @@ final class MainThreadExecutor implements IWorkMonitor
     @Override
     public boolean canWork()
     {
-        return this.state != State.COOLING && MainThread.canExecute();
+        return state != State.COOLING && MainThread.canExecute();
+    }
+
+    @Override
+    public boolean shouldWork()
+    {
+        return state == State.COOL && MainThread.canExecute();
     }
 
     @Override
     public void trackWork( long time, @Nonnull TimeUnit unit )
     {
         long nanoTime = unit.toNanos( time );
-        synchronized( this.queueLock )
+        synchronized( queueLock )
         {
-            this.pendingTime += nanoTime;
+            pendingTime += nanoTime;
         }
 
-        this.consumeTime( nanoTime );
+        consumeTime( nanoTime );
         MainThread.consumeTime( nanoTime );
     }
 
+    private void consumeTime( long time )
+    {
+        Tracking.addServerTiming( computer, time );
+
+        // Reset the budget if moving onto a new tick. We know this is safe, as this will only have happened if
+        // #tickCooling() isn't called, and so we didn't overrun the previous tick.
+        if( currentTick != MainThread.currentTick() )
+        {
+            currentTick = MainThread.currentTick();
+            budget = ComputerCraft.maxMainComputerTime;
+        }
+
+        budget -= time;
+
+        // If we've gone over our limit, mark us as having to cool down.
+        if( budget < 0 && state == State.COOL )
+        {
+            state = State.HOT;
+            MainThread.cooling( this );
+        }
+    }
+
     /**
      * Move this executor forward one tick, replenishing the budget by {@link ComputerCraft#maxMainComputerTime}.
      *
@@ -233,27 +221,29 @@ final class MainThreadExecutor implements IWorkMonitor
      */
     boolean tickCooling()
     {
-        this.state = State.COOLING;
-        this.currentTick = MainThread.currentTick();
-        this.budget = Math.min( this.budget + ComputerCraft.maxMainComputerTime, ComputerCraft.maxMainComputerTime );
-        if( this.budget < ComputerCraft.maxMainComputerTime )
-        {
-            return false;
-        }
+        state = State.COOLING;
+        currentTick = MainThread.currentTick();
+        budget = Math.min( budget + ComputerCraft.maxMainComputerTime, ComputerCraft.maxMainComputerTime );
+        if( budget < ComputerCraft.maxMainComputerTime ) return false;
 
-        this.state = State.COOL;
-        synchronized( this.queueLock )
+        state = State.COOL;
+        synchronized( queueLock )
         {
-            if( !this.tasks.isEmpty() && !this.onQueue )
-            {
-                MainThread.queue( this, false );
-            }
+            if( !tasks.isEmpty() && !onQueue ) MainThread.queue( this, false );
         }
         return true;
     }
 
+    void updateTime()
+    {
+        virtualTime += pendingTime;
+        pendingTime = 0;
+    }
+
     private enum State
     {
-        COOL, HOT, COOLING,
+        COOL,
+        HOT,
+        COOLING,
     }
 }

src/main/java/dan200/computercraft/core/computer/TimeoutState.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.computer;
 
 import dan200.computercraft.core.lua.ILuaMachine;
@@ -14,18 +13,20 @@ import java.util.concurrent.TimeUnit;
 /**
  * Used to measure how long a computer has executed for, and thus the relevant timeout states.
  *
- * Timeouts are mostly used for execution of Lua code: we should ideally never have a state where constructing the APIs or machines themselves takes more
- * than a fraction of a second.
+ * Timeouts are mostly used for execution of Lua code: we should ideally never have a state where constructing the APIs
+ * or machines themselves takes more than a fraction of a second.
  *
- * When a computer runs, it is allowed to run for 7 seconds ({@link #TIMEOUT}). After that point, the "soft abort" flag is set ({@link #isSoftAborted()}).
- * Here, the Lua machine will attempt to abort the program in some safe manner (namely, throwing a "Too long without yielding" error).
+ * When a computer runs, it is allowed to run for 7 seconds ({@link #TIMEOUT}). After that point, the "soft abort" flag
+ * is set ({@link #isSoftAborted()}). Here, the Lua machine will attempt to abort the program in some safe manner
+ * (namely, throwing a "Too long without yielding" error).
  *
- * Now, if a computer still does not stop after that period, they're behaving really badly. 1.5 seconds after a soft abort ({@link #ABORT_TIMEOUT}), we
- * trigger a hard abort (note, this is done from the computer thread manager). This will destroy the entire Lua runtime and shut the computer down.
+ * Now, if a computer still does not stop after that period, they're behaving really badly. 1.5 seconds after a soft
+ * abort ({@link #ABORT_TIMEOUT}), we trigger a hard abort (note, this is done from the computer thread manager). This
+ * will destroy the entire Lua runtime and shut the computer down.
  *
- * The Lua runtime is also allowed to pause execution if there are other computers contesting for work. All computers are allowed to run for {@link
- * ComputerThread#scaledPeriod()} nanoseconds (see {@link #currentDeadline}). After that period, if any computers are waiting to be executed then we'll set
- * the paused flag to true ({@link #isPaused()}.
+ * The Lua runtime is also allowed to pause execution if there are other computers contesting for work. All computers
+ * are allowed to run for {@link ComputerThread#scaledPeriod()} nanoseconds (see {@link #currentDeadline}). After that
+ * period, if any computers are waiting to be executed then we'll set the paused flag to true ({@link #isPaused()}.
  *
  * @see ComputerThread
  * @see ILuaMachine
@@ -33,18 +34,21 @@ import java.util.concurrent.TimeUnit;
  */
 public final class TimeoutState
 {
-    /**
-     * The error message to display when we trigger an abort.
-     */
-    public static final String ABORT_MESSAGE = "Too long without yielding";
     /**
      * The total time a task is allowed to run before aborting in nanoseconds.
      */
     static final long TIMEOUT = TimeUnit.MILLISECONDS.toNanos( 7000 );
+
     /**
      * The time the task is allowed to run after each abort in nanoseconds.
      */
     static final long ABORT_TIMEOUT = TimeUnit.MILLISECONDS.toNanos( 1500 );
+
+    /**
+     * The error message to display when we trigger an abort.
+     */
+    public static final String ABORT_MESSAGE = "Too long without yielding";
+
     private boolean paused;
     private boolean softAbort;
     private volatile boolean hardAbort;
@@ -71,12 +75,12 @@ public final class TimeoutState
 
     long nanoCumulative()
     {
-        return System.nanoTime() - this.cumulativeStart;
+        return System.nanoTime() - cumulativeStart;
     }
 
     long nanoCurrent()
     {
-        return System.nanoTime() - this.currentStart;
+        return System.nanoTime() - currentStart;
     }
 
     /**
@@ -87,26 +91,21 @@ public final class TimeoutState
         // Important: The weird arithmetic here is important, as nanoTime may return negative values, and so we
         // need to handle overflow.
         long now = System.nanoTime();
-        if( !this.paused )
-        {
-            this.paused = this.currentDeadline - now <= 0 && ComputerThread.hasPendingWork(); // now >= currentDeadline
-        }
-        if( !this.softAbort )
-        {
-            this.softAbort = now - this.cumulativeStart - TIMEOUT >= 0; // now - cumulativeStart >= TIMEOUT
-        }
+        if( !paused ) paused = currentDeadline - now <= 0 && ComputerThread.hasPendingWork(); // now >= currentDeadline
+        if( !softAbort ) softAbort = now - cumulativeStart - TIMEOUT >= 0; // now - cumulativeStart >= TIMEOUT
     }
 
     /**
      * Whether we should pause execution of this machine.
      *
-     * This is determined by whether we've consumed our time slice, and if there are other computers waiting to perform work.
+     * This is determined by whether we've consumed our time slice, and if there are other computers waiting to perform
+     * work.
      *
      * @return Whether we should pause execution.
      */
     public boolean isPaused()
     {
-        return this.paused;
+        return paused;
     }
 
     /**
@@ -116,7 +115,7 @@ public final class TimeoutState
      */
     public boolean isSoftAborted()
     {
-        return this.softAbort;
+        return softAbort;
     }
 
     /**
@@ -126,7 +125,7 @@ public final class TimeoutState
      */
     public boolean isHardAborted()
     {
-        return this.hardAbort;
+        return hardAbort;
     }
 
     /**
@@ -134,7 +133,7 @@ public final class TimeoutState
      */
     void hardAbort()
     {
-        this.softAbort = this.hardAbort = true;
+        softAbort = hardAbort = true;
     }
 
     /**
@@ -143,10 +142,10 @@ public final class TimeoutState
     void startTimer()
     {
         long now = System.nanoTime();
-        this.currentStart = now;
-        this.currentDeadline = now + ComputerThread.scaledPeriod();
+        currentStart = now;
+        currentDeadline = now + ComputerThread.scaledPeriod();
         // Compute the "nominal start time".
-        this.cumulativeStart = now - this.cumulativeElapsed;
+        cumulativeStart = now - cumulativeElapsed;
     }
 
     /**
@@ -157,8 +156,8 @@ public final class TimeoutState
     void pauseTimer()
     {
         // We set the cumulative time to difference between current time and "nominal start time".
-        this.cumulativeElapsed = System.nanoTime() - this.cumulativeStart;
-        this.paused = false;
+        cumulativeElapsed = System.nanoTime() - cumulativeStart;
+        paused = false;
     }
 
     /**
@@ -166,7 +165,7 @@ public final class TimeoutState
      */
     void stopTimer()
     {
-        this.cumulativeElapsed = 0;
-        this.paused = this.softAbort = this.hardAbort = false;
+        cumulativeElapsed = 0;
+        paused = softAbort = hardAbort = false;
     }
 }

src/main/java/dan200/computercraft/core/filesystem/ComboMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import dan200.computercraft.api.filesystem.FileOperationException;
@@ -20,24 +19,52 @@ import java.util.Set;
 
 public class ComboMount implements IMount
 {
-    private IMount[] m_parts;
+    private final IMount[] parts;
 
     public ComboMount( IMount[] parts )
     {
-        this.m_parts = parts;
+        this.parts = parts;
     }
 
     // IMount implementation
 
+    @Override
+    public boolean exists( @Nonnull String path ) throws IOException
+    {
+        for( int i = parts.length - 1; i >= 0; --i )
+        {
+            IMount part = parts[i];
+            if( part.exists( path ) )
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public boolean isDirectory( @Nonnull String path ) throws IOException
+    {
+        for( int i = parts.length - 1; i >= 0; --i )
+        {
+            IMount part = parts[i];
+            if( part.isDirectory( path ) )
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+
     @Override
     public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
     {
         // Combine the lists from all the mounts
         List<String> foundFiles = null;
         int foundDirs = 0;
-        for( int i = this.m_parts.length - 1; i >= 0; --i )
+        for( int i = parts.length - 1; i >= 0; --i )
         {
-            IMount part = this.m_parts[i];
+            IMount part = parts[i];
             if( part.exists( path ) && part.isDirectory( path ) )
             {
                 if( foundFiles == null )
@@ -72,13 +99,27 @@ public class ComboMount implements IMount
         }
     }
 
+    @Override
+    public long getSize( @Nonnull String path ) throws IOException
+    {
+        for( int i = parts.length - 1; i >= 0; --i )
+        {
+            IMount part = parts[i];
+            if( part.exists( path ) )
+            {
+                return part.getSize( path );
+            }
+        }
+        throw new FileOperationException( path, "No such file" );
+    }
+
     @Nonnull
     @Override
     public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
-        for( int i = this.m_parts.length - 1; i >= 0; --i )
+        for( int i = parts.length - 1; i >= 0; --i )
         {
-            IMount part = this.m_parts[i];
+            IMount part = parts[i];
             if( part.exists( path ) && !part.isDirectory( path ) )
             {
                 return part.openForRead( path );
@@ -91,9 +132,9 @@ public class ComboMount implements IMount
     @Override
     public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException
     {
-        for( int i = this.m_parts.length - 1; i >= 0; --i )
+        for( int i = parts.length - 1; i >= 0; --i )
         {
-            IMount part = this.m_parts[i];
+            IMount part = parts[i];
             if( part.exists( path ) && !part.isDirectory( path ) )
             {
                 return part.getAttributes( path );
@@ -101,46 +142,4 @@ public class ComboMount implements IMount
         }
         throw new FileOperationException( path, "No such file" );
     }
-
-    @Override
-    public boolean exists( @Nonnull String path ) throws IOException
-    {
-        for( int i = this.m_parts.length - 1; i >= 0; --i )
-        {
-            IMount part = this.m_parts[i];
-            if( part.exists( path ) )
-            {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    @Override
-    public boolean isDirectory( @Nonnull String path ) throws IOException
-    {
-        for( int i = this.m_parts.length - 1; i >= 0; --i )
-        {
-            IMount part = this.m_parts[i];
-            if( part.isDirectory( path ) )
-            {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    @Override
-    public long getSize( @Nonnull String path ) throws IOException
-    {
-        for( int i = this.m_parts.length - 1; i >= 0; --i )
-        {
-            IMount part = this.m_parts[i];
-            if( part.exists( path ) )
-            {
-                return part.getSize( path );
-            }
-        }
-        throw new FileOperationException( path, "No such file" );
-    }
 }

src/main/java/dan200/computercraft/core/filesystem/EmptyMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import dan200.computercraft.api.filesystem.FileOperationException;
@@ -16,18 +15,6 @@ import java.util.List;
 
 public class EmptyMount implements IMount
 {
-    @Override
-    public void list( @Nonnull String path, @Nonnull List<String> contents )
-    {
-    }
-
-    @Nonnull
-    @Override
-    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
-    {
-        throw new FileOperationException( path, "No such file" );
-    }
-
     @Override
     public boolean exists( @Nonnull String path )
     {
@@ -40,9 +27,21 @@ public class EmptyMount implements IMount
         return path.isEmpty();
     }
 
+    @Override
+    public void list( @Nonnull String path, @Nonnull List<String> contents )
+    {
+    }
+
     @Override
     public long getSize( @Nonnull String path )
     {
         return 0;
     }
+
+    @Nonnull
+    @Override
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
+    {
+        throw new FileOperationException( path, "No such file" );
+    }
 }

src/main/java/dan200/computercraft/core/filesystem/FileMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import com.google.common.collect.Sets;
@@ -27,32 +26,383 @@ public class FileMount implements IWritableMount
 {
     private static final int MINIMUM_FILE_SIZE = 500;
     private static final Set<OpenOption> READ_OPTIONS = Collections.singleton( StandardOpenOption.READ );
-    private static final Set<OpenOption> WRITE_OPTIONS = Sets.newHashSet( StandardOpenOption.WRITE,
-        StandardOpenOption.CREATE,
-        StandardOpenOption.TRUNCATE_EXISTING );
+    private static final Set<OpenOption> WRITE_OPTIONS = Sets.newHashSet( StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING );
     private static final Set<OpenOption> APPEND_OPTIONS = Sets.newHashSet( StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.APPEND );
-    private File m_rootPath;
-    private long m_capacity;
-    private long m_usedSpace;
+
+    private class WritableCountingChannel implements WritableByteChannel
+    {
+
+        private final WritableByteChannel inner;
+        long ignoredBytesLeft;
+
+        WritableCountingChannel( WritableByteChannel inner, long bytesToIgnore )
+        {
+            this.inner = inner;
+            ignoredBytesLeft = bytesToIgnore;
+        }
+
+        @Override
+        public int write( @Nonnull ByteBuffer b ) throws IOException
+        {
+            count( b.remaining() );
+            return inner.write( b );
+        }
+
+        void count( long n ) throws IOException
+        {
+            ignoredBytesLeft -= n;
+            if( ignoredBytesLeft < 0 )
+            {
+                long newBytes = -ignoredBytesLeft;
+                ignoredBytesLeft = 0;
+
+                long bytesLeft = capacity - usedSpace;
+                if( newBytes > bytesLeft ) throw new IOException( "Out of space" );
+                usedSpace += newBytes;
+            }
+        }
+
+        @Override
+        public boolean isOpen()
+        {
+            return inner.isOpen();
+        }
+
+        @Override
+        public void close() throws IOException
+        {
+            inner.close();
+        }
+    }
+
+    private class SeekableCountingChannel extends WritableCountingChannel implements SeekableByteChannel
+    {
+        private final SeekableByteChannel inner;
+
+        SeekableCountingChannel( SeekableByteChannel inner, long bytesToIgnore )
+        {
+            super( inner, bytesToIgnore );
+            this.inner = inner;
+        }
+
+        @Override
+        public SeekableByteChannel position( long newPosition ) throws IOException
+        {
+            if( !isOpen() ) throw new ClosedChannelException();
+            if( newPosition < 0 )
+            {
+                throw new IllegalArgumentException( "Cannot seek before the beginning of the stream" );
+            }
+
+            long delta = newPosition - inner.position();
+            if( delta < 0 )
+            {
+                ignoredBytesLeft -= delta;
+            }
+            else
+            {
+                count( delta );
+            }
+
+            return inner.position( newPosition );
+        }
+
+        @Override
+        public SeekableByteChannel truncate( long size ) throws IOException
+        {
+            throw new IOException( "Not yet implemented" );
+        }
+
+        @Override
+        public int read( ByteBuffer dst ) throws ClosedChannelException
+        {
+            if( !inner.isOpen() ) throw new ClosedChannelException();
+            throw new NonReadableChannelException();
+        }
+
+        @Override
+        public long position() throws IOException
+        {
+            return inner.position();
+        }
+
+        @Override
+        public long size() throws IOException
+        {
+            return inner.size();
+        }
+    }
+
+    private final File rootPath;
+    private final long capacity;
+    private long usedSpace;
 
     public FileMount( File rootPath, long capacity )
     {
-        this.m_rootPath = rootPath;
-        this.m_capacity = capacity + MINIMUM_FILE_SIZE;
-        this.m_usedSpace = this.created() ? measureUsedSpace( this.m_rootPath ) : MINIMUM_FILE_SIZE;
+        this.rootPath = rootPath;
+        this.capacity = capacity + MINIMUM_FILE_SIZE;
+        usedSpace = created() ? measureUsedSpace( this.rootPath ) : MINIMUM_FILE_SIZE;
+    }
+
+    // IMount implementation
+
+    @Override
+    public boolean exists( @Nonnull String path )
+    {
+        if( !created() ) return path.isEmpty();
+
+        File file = getRealPath( path );
+        return file.exists();
+    }
+
+    @Override
+    public boolean isDirectory( @Nonnull String path )
+    {
+        if( !created() ) return path.isEmpty();
+
+        File file = getRealPath( path );
+        return file.exists() && file.isDirectory();
+    }
+
+    @Override
+    public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
+    {
+        if( !created() )
+        {
+            if( !path.isEmpty() ) throw new FileOperationException( path, "Not a directory" );
+            return;
+        }
+
+        File file = getRealPath( path );
+        if( !file.exists() || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
+
+        String[] paths = file.list();
+        for( String subPath : paths )
+        {
+            if( new File( file, subPath ).exists() ) contents.add( subPath );
+        }
+    }
+
+    @Override
+    public long getSize( @Nonnull String path ) throws IOException
+    {
+        if( !created() )
+        {
+            if( path.isEmpty() ) return 0;
+        }
+        else
+        {
+            File file = getRealPath( path );
+            if( file.exists() ) return file.isDirectory() ? 0 : file.length();
+        }
+
+        throw new FileOperationException( path, "No such file" );
+    }
+
+    @Nonnull
+    @Override
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
+    {
+        if( created() )
+        {
+            File file = getRealPath( path );
+            if( file.exists() && !file.isDirectory() ) return FileChannel.open( file.toPath(), READ_OPTIONS );
+        }
+
+        throw new FileOperationException( path, "No such file" );
+    }
+
+    @Nonnull
+    @Override
+    public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException
+    {
+        if( created() )
+        {
+            File file = getRealPath( path );
+            if( file.exists() ) return Files.readAttributes( file.toPath(), BasicFileAttributes.class );
+        }
+
+        throw new FileOperationException( path, "No such file" );
+    }
+
+    // IWritableMount implementation
+
+    @Override
+    public void makeDirectory( @Nonnull String path ) throws IOException
+    {
+        create();
+        File file = getRealPath( path );
+        if( file.exists() )
+        {
+            if( !file.isDirectory() ) throw new FileOperationException( path, "File exists" );
+            return;
+        }
+
+        int dirsToCreate = 1;
+        File parent = file.getParentFile();
+        while( !parent.exists() )
+        {
+            ++dirsToCreate;
+            parent = parent.getParentFile();
+        }
+
+        if( getRemainingSpace() < dirsToCreate * MINIMUM_FILE_SIZE )
+        {
+            throw new FileOperationException( path, "Out of space" );
+        }
+
+        if( file.mkdirs() )
+        {
+            usedSpace += dirsToCreate * MINIMUM_FILE_SIZE;
+        }
+        else
+        {
+            throw new FileOperationException( path, "Access denied" );
+        }
+    }
+
+    @Override
+    public void delete( @Nonnull String path ) throws IOException
+    {
+        if( path.isEmpty() ) throw new FileOperationException( path, "Access denied" );
+
+        if( created() )
+        {
+            File file = getRealPath( path );
+            if( file.exists() ) deleteRecursively( file );
+        }
+    }
+
+    private void deleteRecursively( File file ) throws IOException
+    {
+        // Empty directories first
+        if( file.isDirectory() )
+        {
+            String[] children = file.list();
+            for( String aChildren : children )
+            {
+                deleteRecursively( new File( file, aChildren ) );
+            }
+        }
+
+        // Then delete
+        long fileSize = file.isDirectory() ? 0 : file.length();
+        boolean success = file.delete();
+        if( success )
+        {
+            usedSpace -= Math.max( MINIMUM_FILE_SIZE, fileSize );
+        }
+        else
+        {
+            throw new IOException( "Access denied" );
+        }
+    }
+
+    @Nonnull
+    @Override
+    public WritableByteChannel openForWrite( @Nonnull String path ) throws IOException
+    {
+        create();
+        File file = getRealPath( path );
+        if( file.exists() && file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
+
+        if( file.exists() )
+        {
+            usedSpace -= Math.max( file.length(), MINIMUM_FILE_SIZE );
+        }
+        else if( getRemainingSpace() < MINIMUM_FILE_SIZE )
+        {
+            throw new FileOperationException( path, "Out of space" );
+        }
+        usedSpace += MINIMUM_FILE_SIZE;
+
+        return new SeekableCountingChannel( Files.newByteChannel( file.toPath(), WRITE_OPTIONS ), MINIMUM_FILE_SIZE );
+    }
+
+    @Nonnull
+    @Override
+    public WritableByteChannel openForAppend( @Nonnull String path ) throws IOException
+    {
+        if( !created() )
+        {
+            throw new FileOperationException( path, "No such file" );
+        }
+
+        File file = getRealPath( path );
+        if( !file.exists() ) throw new FileOperationException( path, "No such file" );
+        if( file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
+
+        // Allowing seeking when appending is not recommended, so we use a separate channel.
+        return new WritableCountingChannel(
+            Files.newByteChannel( file.toPath(), APPEND_OPTIONS ),
+            Math.max( MINIMUM_FILE_SIZE - file.length(), 0 )
+        );
+    }
+
+    @Override
+    public long getRemainingSpace()
+    {
+        return Math.max( capacity - usedSpace, 0 );
+    }
+
+    @Nonnull
+    @Override
+    public OptionalLong getCapacity()
+    {
+        return OptionalLong.of( capacity - MINIMUM_FILE_SIZE );
+    }
+
+    private File getRealPath( String path )
+    {
+        return new File( rootPath, path );
     }
 
     private boolean created()
     {
-        return this.m_rootPath.exists();
+        return rootPath.exists();
+    }
+
+    private void create() throws IOException
+    {
+        if( !rootPath.exists() )
+        {
+            boolean success = rootPath.mkdirs();
+            if( !success )
+            {
+                throw new IOException( "Access denied" );
+            }
+        }
+    }
+
+    private static class Visitor extends SimpleFileVisitor<Path>
+    {
+        long size;
+
+        @Override
+        public FileVisitResult preVisitDirectory( Path dir, BasicFileAttributes attrs )
+        {
+            size += MINIMUM_FILE_SIZE;
+            return FileVisitResult.CONTINUE;
+        }
+
+        @Override
+        public FileVisitResult visitFile( Path file, BasicFileAttributes attrs )
+        {
+            size += Math.max( attrs.size(), MINIMUM_FILE_SIZE );
+            return FileVisitResult.CONTINUE;
+        }
+
+        @Override
+        public FileVisitResult visitFileFailed( Path file, IOException exc )
+        {
+            ComputerCraft.log.error( "Error computing file size for {}", file, exc );
+            return FileVisitResult.CONTINUE;
+        }
     }
 
     private static long measureUsedSpace( File file )
     {
-        if( !file.exists() )
-        {
-            return 0;
-        }
+        if( !file.exists() ) return 0;
 
         try
         {
@@ -66,410 +416,4 @@ public class FileMount implements IWritableMount
             return 0;
         }
     }
-
-    // IMount implementation
-
-    @Override
-    public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
-    {
-        if( !this.created() )
-        {
-            if( !path.isEmpty() )
-            {
-                throw new FileOperationException( path, "Not a directory" );
-            }
-            return;
-        }
-
-        File file = this.getRealPath( path );
-        if( !file.exists() || !file.isDirectory() )
-        {
-            throw new FileOperationException( path, "Not a directory" );
-        }
-
-        String[] paths = file.list();
-        for( String subPath : paths )
-        {
-            if( new File( file, subPath ).exists() )
-            {
-                contents.add( subPath );
-            }
-        }
-    }
-
-    @Nonnull
-    @Override
-    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
-    {
-        if( this.created() )
-        {
-            File file = this.getRealPath( path );
-            if( file.exists() && !file.isDirectory() )
-            {
-                return FileChannel.open( file.toPath(), READ_OPTIONS );
-            }
-        }
-
-        throw new FileOperationException( path, "No such file" );
-    }
-
-    @Nonnull
-    @Override
-    public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException
-    {
-        if( this.created() )
-        {
-            File file = this.getRealPath( path );
-            if( file.exists() )
-            {
-                return Files.readAttributes( file.toPath(), BasicFileAttributes.class );
-            }
-        }
-
-        throw new FileOperationException( path, "No such file" );
-    }
-
-    @Override
-    public boolean exists( @Nonnull String path )
-    {
-        if( !this.created() )
-        {
-            return path.isEmpty();
-        }
-
-        File file = this.getRealPath( path );
-        return file.exists();
-    }
-
-    @Override
-    public boolean isDirectory( @Nonnull String path )
-    {
-        if( !this.created() )
-        {
-            return path.isEmpty();
-        }
-
-        File file = this.getRealPath( path );
-        return file.exists() && file.isDirectory();
-    }
-
-    @Override
-    public long getSize( @Nonnull String path ) throws IOException
-    {
-        if( !this.created() )
-        {
-            if( path.isEmpty() )
-            {
-                return 0;
-            }
-        }
-        else
-        {
-            File file = this.getRealPath( path );
-            if( file.exists() )
-            {
-                return file.isDirectory() ? 0 : file.length();
-            }
-        }
-
-        throw new FileOperationException( path, "No such file" );
-    }
-
-    // IWritableMount implementation
-
-    private File getRealPath( String path )
-    {
-        return new File( this.m_rootPath, path );
-    }
-
-    @Override
-    public void makeDirectory( @Nonnull String path ) throws IOException
-    {
-        this.create();
-        File file = this.getRealPath( path );
-        if( file.exists() )
-        {
-            if( !file.isDirectory() )
-            {
-                throw new FileOperationException( path, "File exists" );
-            }
-            return;
-        }
-
-        int dirsToCreate = 1;
-        File parent = file.getParentFile();
-        while( !parent.exists() )
-        {
-            ++dirsToCreate;
-            parent = parent.getParentFile();
-        }
-
-        if( this.getRemainingSpace() < dirsToCreate * MINIMUM_FILE_SIZE )
-        {
-            throw new FileOperationException( path, "Out of space" );
-        }
-
-        if( file.mkdirs() )
-        {
-            this.m_usedSpace += dirsToCreate * MINIMUM_FILE_SIZE;
-        }
-        else
-        {
-            throw new FileOperationException( path, "Access denied" );
-        }
-    }
-
-    @Override
-    public void delete( @Nonnull String path ) throws IOException
-    {
-        if( path.isEmpty() )
-        {
-            throw new FileOperationException( path, "Access denied" );
-        }
-
-        if( this.created() )
-        {
-            File file = this.getRealPath( path );
-            if( file.exists() )
-            {
-                this.deleteRecursively( file );
-            }
-        }
-    }
-
-    @Nonnull
-    @Override
-    public WritableByteChannel openForWrite( @Nonnull String path ) throws IOException
-    {
-        this.create();
-        File file = this.getRealPath( path );
-        if( file.exists() && file.isDirectory() )
-        {
-            throw new FileOperationException( path, "Cannot write to directory" );
-        }
-
-        if( file.exists() )
-        {
-            this.m_usedSpace -= Math.max( file.length(), MINIMUM_FILE_SIZE );
-        }
-        else if( this.getRemainingSpace() < MINIMUM_FILE_SIZE )
-        {
-            throw new FileOperationException( path, "Out of space" );
-        }
-        this.m_usedSpace += MINIMUM_FILE_SIZE;
-
-        return new SeekableCountingChannel( Files.newByteChannel( file.toPath(), WRITE_OPTIONS ), MINIMUM_FILE_SIZE );
-    }
-
-    @Nonnull
-    @Override
-    public WritableByteChannel openForAppend( @Nonnull String path ) throws IOException
-    {
-        if( !this.created() )
-        {
-            throw new FileOperationException( path, "No such file" );
-        }
-
-        File file = this.getRealPath( path );
-        if( !file.exists() )
-        {
-            throw new FileOperationException( path, "No such file" );
-        }
-        if( file.isDirectory() )
-        {
-            throw new FileOperationException( path, "Cannot write to directory" );
-        }
-
-        // Allowing seeking when appending is not recommended, so we use a separate channel.
-        return new WritableCountingChannel( Files.newByteChannel( file.toPath(), APPEND_OPTIONS ), Math.max( MINIMUM_FILE_SIZE - file.length(), 0 ) );
-    }
-
-    @Override
-    public long getRemainingSpace()
-    {
-        return Math.max( this.m_capacity - this.m_usedSpace, 0 );
-    }
-
-    @Nonnull
-    @Override
-    public OptionalLong getCapacity()
-    {
-        return OptionalLong.of( this.m_capacity - MINIMUM_FILE_SIZE );
-    }
-
-    private void create() throws IOException
-    {
-        if( !this.m_rootPath.exists() )
-        {
-            boolean success = this.m_rootPath.mkdirs();
-            if( !success )
-            {
-                throw new IOException( "Access denied" );
-            }
-        }
-    }
-
-    private void deleteRecursively( File file ) throws IOException
-    {
-        // Empty directories first
-        if( file.isDirectory() )
-        {
-            String[] children = file.list();
-            for( String aChildren : children )
-            {
-                this.deleteRecursively( new File( file, aChildren ) );
-            }
-        }
-
-        // Then delete
-        long fileSize = file.isDirectory() ? 0 : file.length();
-        boolean success = file.delete();
-        if( success )
-        {
-            this.m_usedSpace -= Math.max( MINIMUM_FILE_SIZE, fileSize );
-        }
-        else
-        {
-            throw new IOException( "Access denied" );
-        }
-    }
-
-    private static class Visitor extends SimpleFileVisitor<Path>
-    {
-        long size;
-
-        @Override
-        public FileVisitResult preVisitDirectory( Path dir, BasicFileAttributes attrs )
-        {
-            this.size += MINIMUM_FILE_SIZE;
-            return FileVisitResult.CONTINUE;
-        }
-
-        @Override
-        public FileVisitResult visitFile( Path file, BasicFileAttributes attrs )
-        {
-            this.size += Math.max( attrs.size(), MINIMUM_FILE_SIZE );
-            return FileVisitResult.CONTINUE;
-        }
-
-        @Override
-        public FileVisitResult visitFileFailed( Path file, IOException exc )
-        {
-            ComputerCraft.log.error( "Error computing file size for {}", file, exc );
-            return FileVisitResult.CONTINUE;
-        }
-    }
-
-    private class WritableCountingChannel implements WritableByteChannel
-    {
-
-        private final WritableByteChannel m_inner;
-        long m_ignoredBytesLeft;
-
-        WritableCountingChannel( WritableByteChannel inner, long bytesToIgnore )
-        {
-            this.m_inner = inner;
-            this.m_ignoredBytesLeft = bytesToIgnore;
-        }
-
-        @Override
-        public int write( @Nonnull ByteBuffer b ) throws IOException
-        {
-            this.count( b.remaining() );
-            return this.m_inner.write( b );
-        }
-
-        void count( long n ) throws IOException
-        {
-            this.m_ignoredBytesLeft -= n;
-            if( this.m_ignoredBytesLeft < 0 )
-            {
-                long newBytes = -this.m_ignoredBytesLeft;
-                this.m_ignoredBytesLeft = 0;
-
-                long bytesLeft = FileMount.this.m_capacity - FileMount.this.m_usedSpace;
-                if( newBytes > bytesLeft )
-                {
-                    throw new IOException( "Out of space" );
-                }
-                FileMount.this.m_usedSpace += newBytes;
-            }
-        }
-
-        @Override
-        public boolean isOpen()
-        {
-            return this.m_inner.isOpen();
-        }
-
-        @Override
-        public void close() throws IOException
-        {
-            this.m_inner.close();
-        }
-    }
-
-    private class SeekableCountingChannel extends WritableCountingChannel implements SeekableByteChannel
-    {
-        private final SeekableByteChannel m_inner;
-
-        SeekableCountingChannel( SeekableByteChannel inner, long bytesToIgnore )
-        {
-            super( inner, bytesToIgnore );
-            this.m_inner = inner;
-        }
-
-        @Override
-        public int read( ByteBuffer dst ) throws ClosedChannelException
-        {
-            if( !this.m_inner.isOpen() )
-            {
-                throw new ClosedChannelException();
-            }
-            throw new NonReadableChannelException();
-        }
-
-        @Override
-        public long position() throws IOException
-        {
-            return this.m_inner.position();
-        }
-
-        @Override
-        public SeekableByteChannel position( long newPosition ) throws IOException
-        {
-            if( !this.isOpen() )
-            {
-                throw new ClosedChannelException();
-            }
-            if( newPosition < 0 )
-            {
-                throw new IllegalArgumentException( "Cannot seek before the beginning of the stream" );
-            }
-
-            long delta = newPosition - this.m_inner.position();
-            if( delta < 0 )
-            {
-                this.m_ignoredBytesLeft -= delta;
-            }
-            else
-            {
-                this.count( delta );
-            }
-
-            return this.m_inner.position( newPosition );
-        }
-
-        @Override
-        public long size() throws IOException
-        {
-            return this.m_inner.size();
-        }
-
-        @Override
-        public SeekableByteChannel truncate( long size ) throws IOException
-        {
-            throw new IOException( "Not yet implemented" );
-        }
-    }
 }

src/main/java/dan200/computercraft/core/filesystem/FileSystemException.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 public class FileSystemException extends Exception

src/main/java/dan200/computercraft/core/filesystem/FileSystemWrapperMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import dan200.computercraft.api.filesystem.IFileSystem;
@@ -18,11 +17,11 @@ import java.util.function.Function;
 
 public class FileSystemWrapperMount implements IFileSystem
 {
-    private final FileSystem m_filesystem;
+    private final FileSystem filesystem;
 
     public FileSystemWrapperMount( FileSystem filesystem )
     {
-        this.m_filesystem = filesystem;
+        this.filesystem = filesystem;
     }
 
     @Override
@@ -30,7 +29,7 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            this.m_filesystem.makeDir( path );
+            filesystem.makeDir( path );
         }
         catch( FileSystemException e )
         {
@@ -43,63 +42,7 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            this.m_filesystem.delete( path );
-        }
-        catch( FileSystemException e )
-        {
-            throw new IOException( e.getMessage() );
-        }
-    }
-
-    @Nonnull
-    @Override
-    public WritableByteChannel openForWrite( @Nonnull String path ) throws IOException
-    {
-        try
-        {
-            return this.m_filesystem.openForWrite( path, false, Function.identity() )
-                .get();
-        }
-        catch( FileSystemException e )
-        {
-            throw new IOException( e.getMessage() );
-        }
-    }
-
-    @Nonnull
-    @Override
-    public WritableByteChannel openForAppend( @Nonnull String path ) throws IOException
-    {
-        try
-        {
-            return this.m_filesystem.openForWrite( path, true, Function.identity() )
-                .get();
-        }
-        catch( FileSystemException e )
-        {
-            throw new IOException( e.getMessage() );
-        }
-    }
-
-    @Override
-    public long getRemainingSpace() throws IOException
-    {
-        try
-        {
-            return this.m_filesystem.getFreeSpace( "/" );
-        }
-        catch( FileSystemException e )
-        {
-            throw new IOException( e.getMessage() );
-        }
-    }
-
-    @Override
-    public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
-    {
-        try
-        {
-            Collections.addAll( contents, this.m_filesystem.list( path ) );
+            filesystem.delete( path );
         }
         catch( FileSystemException e )
         {
@@ -114,8 +57,48 @@ public class FileSystemWrapperMount implements IFileSystem
         try
         {
             // FIXME: Think of a better way of implementing this, so closing this will close on the computer.
-            return this.m_filesystem.openForRead( path, Function.identity() )
-                .get();
+            return filesystem.openForRead( path, Function.identity() ).get();
+        }
+        catch( FileSystemException e )
+        {
+            throw new IOException( e.getMessage() );
+        }
+    }
+
+    @Nonnull
+    @Override
+    public WritableByteChannel openForWrite( @Nonnull String path ) throws IOException
+    {
+        try
+        {
+            return filesystem.openForWrite( path, false, Function.identity() ).get();
+        }
+        catch( FileSystemException e )
+        {
+            throw new IOException( e.getMessage() );
+        }
+    }
+
+    @Nonnull
+    @Override
+    public WritableByteChannel openForAppend( @Nonnull String path ) throws IOException
+    {
+        try
+        {
+            return filesystem.openForWrite( path, true, Function.identity() ).get();
+        }
+        catch( FileSystemException e )
+        {
+            throw new IOException( e.getMessage() );
+        }
+    }
+
+    @Override
+    public long getRemainingSpace() throws IOException
+    {
+        try
+        {
+            return filesystem.getFreeSpace( "/" );
         }
         catch( FileSystemException e )
         {
@@ -128,7 +111,7 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            return this.m_filesystem.exists( path );
+            return filesystem.exists( path );
         }
         catch( FileSystemException e )
         {
@@ -141,7 +124,20 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            return this.m_filesystem.isDir( path );
+            return filesystem.isDir( path );
+        }
+        catch( FileSystemException e )
+        {
+            throw new IOException( e.getMessage() );
+        }
+    }
+
+    @Override
+    public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
+    {
+        try
+        {
+            Collections.addAll( contents, filesystem.list( path ) );
         }
         catch( FileSystemException e )
         {
@@ -154,7 +150,7 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            return this.m_filesystem.getSize( path );
+            return filesystem.getSize( path );
         }
         catch( FileSystemException e )
         {
@@ -165,7 +161,7 @@ public class FileSystemWrapperMount implements IFileSystem
     @Override
     public String combine( String path, String child )
     {
-        return this.m_filesystem.combine( path, child );
+        return filesystem.combine( path, child );
     }
 
     @Override
@@ -173,7 +169,7 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            this.m_filesystem.copy( from, to );
+            filesystem.copy( from, to );
         }
         catch( FileSystemException e )
         {
@@ -186,7 +182,7 @@ public class FileSystemWrapperMount implements IFileSystem
     {
         try
         {
-            this.m_filesystem.move( from, to );
+            filesystem.move( from, to );
         }
         catch( FileSystemException e )
         {

src/main/java/dan200/computercraft/core/filesystem/JarMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import com.google.common.cache.Cache;
@@ -48,18 +47,20 @@ public class JarMount implements IMount
     private static final int MAX_CACHE_SIZE = 64 << 20;
 
     /**
-     * We maintain a cache of the contents of all files in the mount. This allows us to allow seeking within ROM files, and reduces the amount we need to
-     * access disk for computer startup.
+     * We maintain a cache of the contents of all files in the mount. This allows us to allow
+     * seeking within ROM files, and reduces the amount we need to access disk for computer startup.
      */
     private static final Cache<FileEntry, byte[]> CONTENTS_CACHE = CacheBuilder.newBuilder()
         .concurrencyLevel( 4 )
         .expireAfterAccess( 60, TimeUnit.SECONDS )
         .maximumWeight( MAX_CACHE_SIZE )
-        .weakKeys().<FileEntry, byte[]>weigher( ( k, v ) -> v.length ).build();
+        .weakKeys()
+        .<FileEntry, byte[]>weigher( ( k, v ) -> v.length )
+        .build();
 
     /**
-     * We have a {@link ReferenceQueue} of all mounts, a long with their corresponding {@link ZipFile}. If the mount has been destroyed, we clean up after
-     * it.
+     * We have a {@link ReferenceQueue} of all mounts, a long with their corresponding {@link ZipFile}. If
+     * the mount has been destroyed, we clean up after it.
      */
     private static final ReferenceQueue<JarMount> MOUNT_QUEUE = new ReferenceQueue<>();
 
@@ -71,15 +72,12 @@ public class JarMount implements IMount
         // Cleanup any old mounts. It's unlikely that there will be any, but it's best to be safe.
         cleanup();
 
-        if( !jarFile.exists() || jarFile.isDirectory() )
-        {
-            throw new FileNotFoundException( "Cannot find " + jarFile );
-        }
+        if( !jarFile.exists() || jarFile.isDirectory() ) throw new FileNotFoundException( "Cannot find " + jarFile );
 
         // Open the zip file
         try
         {
-            this.zip = new ZipFile( jarFile );
+            zip = new ZipFile( jarFile );
         }
         catch( IOException e )
         {
@@ -87,9 +85,9 @@ public class JarMount implements IMount
         }
 
         // Ensure the root entry exists.
-        if( this.zip.getEntry( subPath ) == null )
+        if( zip.getEntry( subPath ) == null )
         {
-            this.zip.close();
+            zip.close();
             throw new FileNotFoundException( "Zip does not contain path" );
         }
 
@@ -97,50 +95,49 @@ public class JarMount implements IMount
         new MountReference( this );
 
         // Read in all the entries
-        this.root = new FileEntry();
-        Enumeration<? extends ZipEntry> zipEntries = this.zip.entries();
+        root = new FileEntry();
+        Enumeration<? extends ZipEntry> zipEntries = zip.entries();
         while( zipEntries.hasMoreElements() )
         {
             ZipEntry entry = zipEntries.nextElement();
 
             String entryPath = entry.getName();
-            if( !entryPath.startsWith( subPath ) )
-            {
-                continue;
-            }
+            if( !entryPath.startsWith( subPath ) ) continue;
 
             String localPath = FileSystem.toLocal( entryPath, subPath );
-            this.create( entry, localPath );
+            create( entry, localPath );
         }
     }
 
-    private static void cleanup()
+    private FileEntry get( String path )
     {
-        Reference<? extends JarMount> next;
-        while( (next = MOUNT_QUEUE.poll()) != null )
+        FileEntry lastEntry = root;
+        int lastIndex = 0;
+
+        while( lastEntry != null && lastIndex < path.length() )
         {
-            IoUtil.closeQuietly( ((MountReference) next).file );
+            int nextIndex = path.indexOf( '/', lastIndex );
+            if( nextIndex < 0 ) nextIndex = path.length();
+
+            lastEntry = lastEntry.children == null ? null : lastEntry.children.get( path.substring( lastIndex, nextIndex ) );
+            lastIndex = nextIndex + 1;
         }
+
+        return lastEntry;
     }
 
     private void create( ZipEntry entry, String localPath )
     {
-        FileEntry lastEntry = this.root;
+        FileEntry lastEntry = root;
 
         int lastIndex = 0;
         while( lastIndex < localPath.length() )
         {
             int nextIndex = localPath.indexOf( '/', lastIndex );
-            if( nextIndex < 0 )
-            {
-                nextIndex = localPath.length();
-            }
+            if( nextIndex < 0 ) nextIndex = localPath.length();
 
             String part = localPath.substring( lastIndex, nextIndex );
-            if( lastEntry.children == null )
-            {
-                lastEntry.children = new HashMap<>( 0 );
-            }
+            if( lastEntry.children == null ) lastEntry.children = new HashMap<>( 0 );
 
             FileEntry nextEntry = lastEntry.children.get( part );
             if( nextEntry == null || !nextEntry.isDirectory() )
@@ -155,42 +152,54 @@ public class JarMount implements IMount
         lastEntry.setup( entry );
     }
 
+    @Override
+    public boolean exists( @Nonnull String path )
+    {
+        return get( path ) != null;
+    }
+
+    @Override
+    public boolean isDirectory( @Nonnull String path )
+    {
+        FileEntry file = get( path );
+        return file != null && file.isDirectory();
+    }
+
     @Override
     public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
     {
-        FileEntry file = this.get( path );
-        if( file == null || !file.isDirectory() )
-        {
-            throw new FileOperationException( path, "Not a directory" );
-        }
+        FileEntry file = get( path );
+        if( file == null || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
 
         file.list( contents );
     }
 
+    @Override
+    public long getSize( @Nonnull String path ) throws IOException
+    {
+        FileEntry file = get( path );
+        if( file != null ) return file.size;
+        throw new FileOperationException( path, "No such file" );
+    }
+
     @Nonnull
     @Override
     public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
-        FileEntry file = this.get( path );
+        FileEntry file = get( path );
         if( file != null && !file.isDirectory() )
         {
             byte[] contents = CONTENTS_CACHE.getIfPresent( file );
-            if( contents != null )
-            {
-                return new ArrayByteChannel( contents );
-            }
+            if( contents != null ) return new ArrayByteChannel( contents );
 
             try
             {
-                ZipEntry entry = this.zip.getEntry( file.path );
+                ZipEntry entry = zip.getEntry( file.path );
                 if( entry != null )
                 {
-                    try( InputStream stream = this.zip.getInputStream( entry ) )
+                    try( InputStream stream = zip.getInputStream( entry ) )
                     {
-                        if( stream.available() > MAX_CACHED_SIZE )
-                        {
-                            return Channels.newChannel( stream );
-                        }
+                        if( stream.available() > MAX_CACHED_SIZE ) return Channels.newChannel( stream );
 
                         contents = ByteStreams.toByteArray( stream );
                         CONTENTS_CACHE.put( file, contents );
@@ -211,63 +220,16 @@ public class JarMount implements IMount
     @Override
     public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException
     {
-        FileEntry file = this.get( path );
+        FileEntry file = get( path );
         if( file != null )
         {
-            ZipEntry entry = this.zip.getEntry( file.path );
-            if( entry != null )
-            {
-                return new ZipEntryAttributes( entry );
-            }
+            ZipEntry entry = zip.getEntry( file.path );
+            if( entry != null ) return new ZipEntryAttributes( entry );
         }
 
         throw new FileOperationException( path, "No such file" );
     }
 
-    @Override
-    public boolean exists( @Nonnull String path )
-    {
-        return this.get( path ) != null;
-    }
-
-    private FileEntry get( String path )
-    {
-        FileEntry lastEntry = this.root;
-        int lastIndex = 0;
-
-        while( lastEntry != null && lastIndex < path.length() )
-        {
-            int nextIndex = path.indexOf( '/', lastIndex );
-            if( nextIndex < 0 )
-            {
-                nextIndex = path.length();
-            }
-
-            lastEntry = lastEntry.children == null ? null : lastEntry.children.get( path.substring( lastIndex, nextIndex ) );
-            lastIndex = nextIndex + 1;
-        }
-
-        return lastEntry;
-    }
-
-    @Override
-    public boolean isDirectory( @Nonnull String path )
-    {
-        FileEntry file = this.get( path );
-        return file != null && file.isDirectory();
-    }
-
-    @Override
-    public long getSize( @Nonnull String path ) throws IOException
-    {
-        FileEntry file = this.get( path );
-        if( file != null )
-        {
-            return file.size;
-        }
-        throw new FileOperationException( path, "No such file" );
-    }
-
     private static class FileEntry
     {
         String path;
@@ -276,25 +238,19 @@ public class JarMount implements IMount
 
         void setup( ZipEntry entry )
         {
-            this.path = entry.getName();
-            this.size = entry.getSize();
-            if( this.children == null && entry.isDirectory() )
-            {
-                this.children = new HashMap<>( 0 );
-            }
+            path = entry.getName();
+            size = entry.getSize();
+            if( children == null && entry.isDirectory() ) children = new HashMap<>( 0 );
         }
 
         boolean isDirectory()
         {
-            return this.children != null;
+            return children != null;
         }
 
         void list( List<String> contents )
         {
-            if( this.children != null )
-            {
-                contents.addAll( this.children.keySet() );
-            }
+            if( children != null ) contents.addAll( children.keySet() );
         }
     }
 
@@ -309,9 +265,14 @@ public class JarMount implements IMount
         }
     }
 
+    private static void cleanup()
+    {
+        Reference<? extends JarMount> next;
+        while( (next = MOUNT_QUEUE.poll()) != null ) IoUtil.closeQuietly( ((MountReference) next).file );
+    }
+
     private static class ZipEntryAttributes implements BasicFileAttributes
     {
-        private static final FileTime EPOCH = FileTime.from( Instant.EPOCH );
         private final ZipEntry entry;
 
         ZipEntryAttributes( ZipEntry entry )
@@ -322,32 +283,32 @@ public class JarMount implements IMount
         @Override
         public FileTime lastModifiedTime()
         {
-            return orEpoch( this.entry.getLastModifiedTime() );
+            return orEpoch( entry.getLastModifiedTime() );
         }
 
         @Override
         public FileTime lastAccessTime()
         {
-            return orEpoch( this.entry.getLastAccessTime() );
+            return orEpoch( entry.getLastAccessTime() );
         }
 
         @Override
         public FileTime creationTime()
         {
-            FileTime time = this.entry.getCreationTime();
-            return time == null ? this.lastModifiedTime() : time;
+            FileTime time = entry.getCreationTime();
+            return time == null ? lastModifiedTime() : time;
         }
 
         @Override
         public boolean isRegularFile()
         {
-            return !this.entry.isDirectory();
+            return !entry.isDirectory();
         }
 
         @Override
         public boolean isDirectory()
         {
-            return this.entry.isDirectory();
+            return entry.isDirectory();
         }
 
         @Override
@@ -365,7 +326,7 @@ public class JarMount implements IMount
         @Override
         public long size()
         {
-            return this.entry.getSize();
+            return entry.getSize();
         }
 
         @Override
@@ -374,6 +335,7 @@ public class JarMount implements IMount
             return null;
         }
 
+        private static final FileTime EPOCH = FileTime.from( Instant.EPOCH );
 
         private static FileTime orEpoch( FileTime time )
         {

src/main/java/dan200/computercraft/core/filesystem/MountWrapper.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import dan200.computercraft.api.filesystem.FileOperationException;
@@ -33,7 +32,7 @@ class MountWrapper
         this.label = label;
         this.location = location;
         this.mount = mount;
-        this.writableMount = null;
+        writableMount = null;
     }
 
     MountWrapper( String label, String location, IWritableMount mount )
@@ -41,29 +40,26 @@ class MountWrapper
         this.label = label;
         this.location = location;
         this.mount = mount;
-        this.writableMount = mount;
+        writableMount = mount;
     }
 
     public String getLabel()
     {
-        return this.label;
+        return label;
     }
 
     public String getLocation()
     {
-        return this.location;
+        return location;
     }
 
     public long getFreeSpace()
     {
-        if( this.writableMount == null )
-        {
-            return 0;
-        }
+        if( writableMount == null ) return 0;
 
         try
         {
-            return this.writableMount.getRemainingSpace();
+            return writableMount.getRemainingSpace();
         }
         catch( IOException e )
         {
@@ -73,50 +69,242 @@ class MountWrapper
 
     public OptionalLong getCapacity()
     {
-        return this.writableMount == null ? OptionalLong.empty() : this.writableMount.getCapacity();
+        return writableMount == null ? OptionalLong.empty() : writableMount.getCapacity();
     }
 
     public boolean isReadOnly( String path )
     {
-        return this.writableMount == null;
+        return writableMount == null;
     }
 
     public boolean exists( String path ) throws FileSystemException
     {
-        path = this.toLocal( path );
+        path = toLocal( path );
         try
         {
-            return this.mount.exists( path );
+            return mount.exists( path );
         }
         catch( IOException e )
         {
-            throw this.localExceptionOf( path, e );
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public boolean isDirectory( String path ) throws FileSystemException
+    {
+        path = toLocal( path );
+        try
+        {
+            return mount.exists( path ) && mount.isDirectory( path );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public void list( String path, List<String> contents ) throws FileSystemException
+    {
+        path = toLocal( path );
+        try
+        {
+            if( !mount.exists( path ) || !mount.isDirectory( path ) )
+            {
+                throw localExceptionOf( path, "Not a directory" );
+            }
+
+            mount.list( path, contents );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public long getSize( String path ) throws FileSystemException
+    {
+        path = toLocal( path );
+        try
+        {
+            if( !mount.exists( path ) ) throw localExceptionOf( path, "No such file" );
+            return mount.isDirectory( path ) ? 0 : mount.getSize( path );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    @Nonnull
+    public BasicFileAttributes getAttributes( String path ) throws FileSystemException
+    {
+        path = toLocal( path );
+        try
+        {
+            if( !mount.exists( path ) ) throw localExceptionOf( path, "No such file" );
+            return mount.getAttributes( path );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public ReadableByteChannel openForRead( String path ) throws FileSystemException
+    {
+        path = toLocal( path );
+        try
+        {
+            if( mount.exists( path ) && !mount.isDirectory( path ) )
+            {
+                return mount.openForRead( path );
+            }
+            else
+            {
+                throw localExceptionOf( path, "No such file" );
+            }
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public void makeDirectory( String path ) throws FileSystemException
+    {
+        if( writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+        path = toLocal( path );
+        try
+        {
+            if( mount.exists( path ) )
+            {
+                if( !mount.isDirectory( path ) ) throw localExceptionOf( path, "File exists" );
+            }
+            else
+            {
+                writableMount.makeDirectory( path );
+            }
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public void delete( String path ) throws FileSystemException
+    {
+        if( writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+        path = toLocal( path );
+        try
+        {
+            if( mount.exists( path ) )
+            {
+                writableMount.delete( path );
+            }
+        }
+        catch( AccessDeniedException e )
+        {
+            throw new FileSystemException( "Access denied" );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public WritableByteChannel openForWrite( String path ) throws FileSystemException
+    {
+        if( writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+        path = toLocal( path );
+        try
+        {
+            if( mount.exists( path ) && mount.isDirectory( path ) )
+            {
+                throw localExceptionOf( path, "Cannot write to directory" );
+            }
+            else
+            {
+                if( !path.isEmpty() )
+                {
+                    String dir = FileSystem.getDirectory( path );
+                    if( !dir.isEmpty() && !mount.exists( path ) )
+                    {
+                        writableMount.makeDirectory( dir );
+                    }
+                }
+                return writableMount.openForWrite( path );
+            }
+        }
+        catch( AccessDeniedException e )
+        {
+            throw new FileSystemException( "Access denied" );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
+        }
+    }
+
+    public WritableByteChannel openForAppend( String path ) throws FileSystemException
+    {
+        if( writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+        path = toLocal( path );
+        try
+        {
+            if( !mount.exists( path ) )
+            {
+                if( !path.isEmpty() )
+                {
+                    String dir = FileSystem.getDirectory( path );
+                    if( !dir.isEmpty() && !mount.exists( path ) )
+                    {
+                        writableMount.makeDirectory( dir );
+                    }
+                }
+                return writableMount.openForWrite( path );
+            }
+            else if( mount.isDirectory( path ) )
+            {
+                throw localExceptionOf( path, "Cannot write to directory" );
+            }
+            else
+            {
+                return writableMount.openForAppend( path );
+            }
+        }
+        catch( AccessDeniedException e )
+        {
+            throw new FileSystemException( "Access denied" );
+        }
+        catch( IOException e )
+        {
+            throw localExceptionOf( path, e );
         }
     }
 
     private String toLocal( String path )
     {
-        return FileSystem.toLocal( path, this.location );
+        return FileSystem.toLocal( path, location );
     }
 
     private FileSystemException localExceptionOf( @Nullable String localPath, @Nonnull IOException e )
     {
-        if( !this.location.isEmpty() && e instanceof FileOperationException )
+        if( !location.isEmpty() && e instanceof FileOperationException )
         {
             FileOperationException ex = (FileOperationException) e;
-            if( ex.getFilename() != null )
-            {
-                return this.localExceptionOf( ex.getFilename(), ex.getMessage() );
-            }
+            if( ex.getFilename() != null ) return localExceptionOf( ex.getFilename(), ex.getMessage() );
         }
 
         if( e instanceof java.nio.file.FileSystemException )
         {
             // This error will contain the absolute path, leaking information about where MC is installed. We drop that,
             // just taking the reason. We assume that the error refers to the input path.
-            String message = ((java.nio.file.FileSystemException) e).getReason()
-                .trim();
-            return localPath == null ? new FileSystemException( message ) : this.localExceptionOf( localPath, message );
+            String message = ((java.nio.file.FileSystemException) e).getReason().trim();
+            return localPath == null ? new FileSystemException( message ) : localExceptionOf( localPath, message );
         }
 
         return new FileSystemException( e.getMessage() );
@@ -124,10 +312,7 @@ class MountWrapper
 
     private FileSystemException localExceptionOf( String path, String message )
     {
-        if( !this.location.isEmpty() )
-        {
-            path = path.isEmpty() ? this.location : this.location + "/" + path;
-        }
+        if( !location.isEmpty() ) path = path.isEmpty() ? location : location + "/" + path;
         return exceptionOf( path, message );
     }
 
@@ -135,221 +320,4 @@ class MountWrapper
     {
         return new FileSystemException( "/" + path + ": " + message );
     }
-
-    public boolean isDirectory( String path ) throws FileSystemException
-    {
-        path = this.toLocal( path );
-        try
-        {
-            return this.mount.exists( path ) && this.mount.isDirectory( path );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public void list( String path, List<String> contents ) throws FileSystemException
-    {
-        path = this.toLocal( path );
-        try
-        {
-            if( !this.mount.exists( path ) || !this.mount.isDirectory( path ) )
-            {
-                throw this.localExceptionOf( path, "Not a directory" );
-            }
-
-            this.mount.list( path, contents );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public long getSize( String path ) throws FileSystemException
-    {
-        path = this.toLocal( path );
-        try
-        {
-            if( !this.mount.exists( path ) )
-            {
-                throw this.localExceptionOf( path, "No such file" );
-            }
-            return this.mount.isDirectory( path ) ? 0 : this.mount.getSize( path );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    @Nonnull
-    public BasicFileAttributes getAttributes( String path ) throws FileSystemException
-    {
-        path = this.toLocal( path );
-        try
-        {
-            if( !this.mount.exists( path ) )
-            {
-                throw this.localExceptionOf( path, "No such file" );
-            }
-            return this.mount.getAttributes( path );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public ReadableByteChannel openForRead( String path ) throws FileSystemException
-    {
-        path = this.toLocal( path );
-        try
-        {
-            if( this.mount.exists( path ) && !this.mount.isDirectory( path ) )
-            {
-                return this.mount.openForRead( path );
-            }
-            else
-            {
-                throw this.localExceptionOf( path, "No such file" );
-            }
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public void makeDirectory( String path ) throws FileSystemException
-    {
-        if( this.writableMount == null )
-        {
-            throw exceptionOf( path, "Access denied" );
-        }
-
-        path = this.toLocal( path );
-        try
-        {
-            if( this.mount.exists( path ) )
-            {
-                if( !this.mount.isDirectory( path ) )
-                {
-                    throw this.localExceptionOf( path, "File exists" );
-                }
-            }
-            else
-            {
-                this.writableMount.makeDirectory( path );
-            }
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public void delete( String path ) throws FileSystemException
-    {
-        if( this.writableMount == null )
-        {
-            throw exceptionOf( path, "Access denied" );
-        }
-
-        path = this.toLocal( path );
-        try
-        {
-            if( this.mount.exists( path ) )
-            {
-                this.writableMount.delete( path );
-            }
-        }
-        catch( AccessDeniedException e )
-        {
-            throw new FileSystemException( "Access denied" );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public WritableByteChannel openForWrite( String path ) throws FileSystemException
-    {
-        if( this.writableMount == null )
-        {
-            throw exceptionOf( path, "Access denied" );
-        }
-
-        path = this.toLocal( path );
-        try
-        {
-            if( this.mount.exists( path ) && this.mount.isDirectory( path ) )
-            {
-                throw this.localExceptionOf( path, "Cannot write to directory" );
-            }
-            else
-            {
-                if( !path.isEmpty() )
-                {
-                    String dir = FileSystem.getDirectory( path );
-                    if( !dir.isEmpty() && !this.mount.exists( path ) )
-                    {
-                        this.writableMount.makeDirectory( dir );
-                    }
-                }
-                return this.writableMount.openForWrite( path );
-            }
-        }
-        catch( AccessDeniedException e )
-        {
-            throw new FileSystemException( "Access denied" );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
-
-    public WritableByteChannel openForAppend( String path ) throws FileSystemException
-    {
-        if( this.writableMount == null )
-        {
-            throw exceptionOf( path, "Access denied" );
-        }
-
-        path = this.toLocal( path );
-        try
-        {
-            if( !this.mount.exists( path ) )
-            {
-                if( !path.isEmpty() )
-                {
-                    String dir = FileSystem.getDirectory( path );
-                    if( !dir.isEmpty() && !this.mount.exists( path ) )
-                    {
-                        this.writableMount.makeDirectory( dir );
-                    }
-                }
-                return this.writableMount.openForWrite( path );
-            }
-            else if( this.mount.isDirectory( path ) )
-            {
-                throw this.localExceptionOf( path, "Cannot write to directory" );
-            }
-            else
-            {
-                return this.writableMount.openForAppend( path );
-            }
-        }
-        catch( AccessDeniedException e )
-        {
-            throw new FileSystemException( "Access denied" );
-        }
-        catch( IOException e )
-        {
-            throw this.localExceptionOf( path, e );
-        }
-    }
 }

src/main/java/dan200/computercraft/core/filesystem/ResourceMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import com.google.common.cache.Cache;
@@ -49,17 +48,18 @@ public final class ResourceMount implements IMount
     private static final byte[] TEMP_BUFFER = new byte[8192];
 
     /**
-     * We maintain a cache of the contents of all files in the mount. This allows us to allow seeking within ROM files, and reduces the amount we need to
-     * access disk for computer startup.
+     * We maintain a cache of the contents of all files in the mount. This allows us to allow
+     * seeking within ROM files, and reduces the amount we need to access disk for computer startup.
      */
     private static final Cache<FileEntry, byte[]> CONTENTS_CACHE = CacheBuilder.newBuilder()
         .concurrencyLevel( 4 )
         .expireAfterAccess( 60, TimeUnit.SECONDS )
         .maximumWeight( MAX_CACHE_SIZE )
-        .weakKeys().<FileEntry, byte[]>weigher( ( k, v ) -> v.length ).build();
+        .weakKeys()
+        .<FileEntry, byte[]>weigher( ( k, v ) -> v.length )
+        .build();
 
-    private static final MapMaker CACHE_TEMPLATE = new MapMaker().weakValues()
-        .concurrencyLevel( 1 );
+    private static final MapMaker CACHE_TEMPLATE = new MapMaker().weakValues().concurrencyLevel( 1 );
 
     /**
      * Maintain a cache of currently loaded resource mounts. This cache is invalidated when currentManager changes.
@@ -73,6 +73,25 @@ public final class ResourceMount implements IMount
     @Nullable
     private FileEntry root;
 
+    public static ResourceMount get( String namespace, String subPath, ReloadableResourceManager manager )
+    {
+        Map<Identifier, ResourceMount> cache;
+
+        synchronized( MOUNT_CACHE )
+        {
+            cache = MOUNT_CACHE.get( manager );
+            if( cache == null ) MOUNT_CACHE.put( manager, cache = CACHE_TEMPLATE.makeMap() );
+        }
+
+        Identifier path = new Identifier( namespace, subPath );
+        synchronized( cache )
+        {
+            ResourceMount mount = cache.get( path );
+            if( mount == null ) cache.put( path, mount = new ResourceMount( namespace, subPath, manager ) );
+            return mount;
+        }
+    }
+
     private ResourceMount( String namespace, String subPath, ReloadableResourceManager manager )
     {
         this.namespace = namespace;
@@ -80,10 +99,7 @@ public final class ResourceMount implements IMount
         this.manager = manager;
 
         Listener.INSTANCE.add( manager, this );
-        if( this.root == null )
-        {
-            this.load();
-        }
+        if( root == null ) load();
     }
 
     private void load()
@@ -98,8 +114,8 @@ public final class ResourceMount implements IMount
 
             if( !file.getNamespace().equals( namespace ) ) continue;
 
-            String localPath = FileSystem.toLocal( file.getPath(), this.subPath );
-            this.create( newRoot, localPath );
+            String localPath = FileSystem.toLocal( file.getPath(), subPath );
+            create( newRoot, localPath );
             hasAny = true;
         }
 
@@ -115,22 +131,33 @@ public final class ResourceMount implements IMount
         }
     }
 
+    private FileEntry get( String path )
+    {
+        FileEntry lastEntry = root;
+        int lastIndex = 0;
+
+        while( lastEntry != null && lastIndex < path.length() )
+        {
+            int nextIndex = path.indexOf( '/', lastIndex );
+            if( nextIndex < 0 ) nextIndex = path.length();
+
+            lastEntry = lastEntry.children == null ? null : lastEntry.children.get( path.substring( lastIndex, nextIndex ) );
+            lastIndex = nextIndex + 1;
+        }
+
+        return lastEntry;
+    }
+
     private void create( FileEntry lastEntry, String path )
     {
         int lastIndex = 0;
         while( lastIndex < path.length() )
         {
             int nextIndex = path.indexOf( '/', lastIndex );
-            if( nextIndex < 0 )
-            {
-                nextIndex = path.length();
-            }
+            if( nextIndex < 0 ) nextIndex = path.length();
 
             String part = path.substring( lastIndex, nextIndex );
-            if( lastEntry.children == null )
-            {
-                lastEntry.children = new HashMap<>();
-            }
+            if( lastEntry.children == null ) lastEntry.children = new HashMap<>();
 
             FileEntry nextEntry = lastEntry.children.get( part );
             if( nextEntry == null )
@@ -138,7 +165,7 @@ public final class ResourceMount implements IMount
                 Identifier childPath;
                 try
                 {
-                    childPath = new Identifier( this.namespace, this.subPath + "/" + path );
+                    childPath = new Identifier( namespace, subPath + "/" + path );
                 }
                 catch( InvalidIdentifierException e )
                 {
@@ -153,137 +180,43 @@ public final class ResourceMount implements IMount
         }
     }
 
-    public static ResourceMount get( String namespace, String subPath, ReloadableResourceManager manager )
-    {
-        Map<Identifier, ResourceMount> cache;
-
-        synchronized( MOUNT_CACHE )
-        {
-            cache = MOUNT_CACHE.get( manager );
-            if( cache == null )
-            {
-                MOUNT_CACHE.put( manager, cache = CACHE_TEMPLATE.makeMap() );
-            }
-        }
-
-        Identifier path = new Identifier( namespace, subPath );
-        synchronized( cache )
-        {
-            ResourceMount mount = cache.get( path );
-            if( mount == null )
-            {
-                cache.put( path, mount = new ResourceMount( namespace, subPath, manager ) );
-            }
-            return mount;
-        }
-    }
-
-    @Override
-    public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
-    {
-        FileEntry file = this.get( path );
-        if( file == null || !file.isDirectory() )
-        {
-            throw new IOException( "/" + path + ": Not a directory" );
-        }
-
-        file.list( contents );
-    }
-
-    @Nonnull
-    @Override
-    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
-    {
-        FileEntry file = this.get( path );
-        if( file != null && !file.isDirectory() )
-        {
-            byte[] contents = CONTENTS_CACHE.getIfPresent( file );
-            if( contents != null )
-            {
-                return new ArrayByteChannel( contents );
-            }
-
-            try
-            {
-                InputStream stream = manager.getResource( file.identifier ).getInputStream();
-                if( stream.available() > MAX_CACHED_SIZE ) return Channels.newChannel( stream );
-
-                try
-                {
-                    contents = ByteStreams.toByteArray( stream );
-                }
-                finally
-                {
-                    IoUtil.closeQuietly( stream );
-                }
-                CONTENTS_CACHE.put( file, contents );
-                return new ArrayByteChannel( contents );
-            }
-            catch( FileNotFoundException ignored )
-            {
-            }
-        }
-
-        throw new IOException( "/" + path + ": No such file" );
-    }
-
     @Override
     public boolean exists( @Nonnull String path )
     {
-        return this.get( path ) != null;
-    }
-
-    private FileEntry get( String path )
-    {
-        FileEntry lastEntry = this.root;
-        int lastIndex = 0;
-
-        while( lastEntry != null && lastIndex < path.length() )
-        {
-            int nextIndex = path.indexOf( '/', lastIndex );
-            if( nextIndex < 0 )
-            {
-                nextIndex = path.length();
-            }
-
-            lastEntry = lastEntry.children == null ? null : lastEntry.children.get( path.substring( lastIndex, nextIndex ) );
-            lastIndex = nextIndex + 1;
-        }
-
-        return lastEntry;
+        return get( path ) != null;
     }
 
     @Override
     public boolean isDirectory( @Nonnull String path )
     {
-        FileEntry file = this.get( path );
+        FileEntry file = get( path );
         return file != null && file.isDirectory();
     }
 
+    @Override
+    public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
+    {
+        FileEntry file = get( path );
+        if( file == null || !file.isDirectory() ) throw new IOException( "/" + path + ": Not a directory" );
+
+        file.list( contents );
+    }
+
     @Override
     public long getSize( @Nonnull String path ) throws IOException
     {
-        FileEntry file = this.get( path );
+        FileEntry file = get( path );
         if( file != null )
         {
-            if( file.size != -1 )
-            {
-                return file.size;
-            }
-            if( file.isDirectory() )
-            {
-                return file.size = 0;
-            }
+            if( file.size != -1 ) return file.size;
+            if( file.isDirectory() ) return file.size = 0;
 
             byte[] contents = CONTENTS_CACHE.getIfPresent( file );
-            if( contents != null )
-            {
-                return file.size = contents.length;
-            }
+            if( contents != null ) return file.size = contents.length;
 
             try
             {
-                Resource resource = this.manager.getResource( file.identifier );
+                Resource resource = manager.getResource( file.identifier );
                 InputStream s = resource.getInputStream();
                 int total = 0, read = 0;
                 do
@@ -303,6 +236,41 @@ public final class ResourceMount implements IMount
         throw new IOException( "/" + path + ": No such file" );
     }
 
+    @Nonnull
+    @Override
+    public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
+    {
+        FileEntry file = get( path );
+        if( file != null && !file.isDirectory() )
+        {
+            byte[] contents = CONTENTS_CACHE.getIfPresent( file );
+            if( contents != null ) return new ArrayByteChannel( contents );
+
+            try
+            {
+                InputStream stream = manager.getResource( file.identifier ).getInputStream();
+                if( stream.available() > MAX_CACHED_SIZE ) return Channels.newChannel( stream );
+
+                try
+                {
+                    contents = ByteStreams.toByteArray( stream );
+                }
+                finally
+                {
+                    IoUtil.closeQuietly( stream );
+                }
+
+                CONTENTS_CACHE.put( file, contents );
+                return new ArrayByteChannel( contents );
+            }
+            catch( FileNotFoundException ignored )
+            {
+            }
+        }
+
+        throw new IOException( "/" + path + ": No such file" );
+    }
+
     private static class FileEntry
     {
         final Identifier identifier;
@@ -316,21 +284,20 @@ public final class ResourceMount implements IMount
 
         boolean isDirectory()
         {
-            return this.children != null;
+            return children != null;
         }
 
         void list( List<String> contents )
         {
-            if( this.children != null )
-            {
-                contents.addAll( this.children.keySet() );
-            }
+            if( children != null ) contents.addAll( children.keySet() );
         }
     }
 
     /**
-     * While people should really be keeping a permanent reference to this, some people construct it every method call, so let's make this as small as
-     * possible.
+     * A {@link ResourceReloadListener} which reloads any associated mounts.
+     *
+     * While people should really be keeping a permanent reference to this, some people construct it every
+     * method call, so let's make this as small as possible.
      */
     static class Listener implements ResourceReloadListener
     {
@@ -340,32 +307,25 @@ public final class ResourceMount implements IMount
         private final Set<ReloadableResourceManager> managers = Collections.newSetFromMap( new WeakHashMap<>() );
 
         @Override
-        public CompletableFuture<Void> reload( Synchronizer synchronizer, ResourceManager resourceManager, Profiler profiler, Profiler profiler1,
-                                               Executor executor, Executor executor1 )
+        public CompletableFuture<Void> reload( Synchronizer synchronizer, ResourceManager manager, Profiler prepareProfiler, Profiler applyProfiler, Executor prepareExecutor, Executor applyExecutor )
         {
             return CompletableFuture.runAsync( () -> {
-                profiler.push( "Mount reloading" );
+                prepareProfiler.push( "Mount reloading" );
                 try
                 {
-                    for( ResourceMount mount : this.mounts )
-                    {
-                        mount.load();
-                    }
+                    for( ResourceMount mount : this.mounts ) mount.load();
                 }
                 finally
                 {
-                    profiler.pop();
+                    prepareProfiler.pop();
                 }
-            }, executor );
+            }, prepareExecutor );
         }
 
         synchronized void add( ReloadableResourceManager manager, ResourceMount mount )
         {
-            if( this.managers.add( manager ) )
-            {
-                manager.registerListener( this );
-            }
-            this.mounts.add( mount );
+            if( managers.add( manager ) ) manager.registerListener( this );
+            mounts.add( mount );
         }
     }
 }

src/main/java/dan200/computercraft/core/filesystem/SubMount.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.filesystem;
 
 import dan200.computercraft.api.filesystem.IMount;
@@ -16,8 +15,8 @@ import java.util.List;
 
 public class SubMount implements IMount
 {
-    private IMount parent;
-    private String subPath;
+    private final IMount parent;
+    private final String subPath;
 
     public SubMount( IMount parent, String subPath )
     {
@@ -25,46 +24,46 @@ public class SubMount implements IMount
         this.subPath = subPath;
     }
 
+    @Override
+    public boolean exists( @Nonnull String path ) throws IOException
+    {
+        return parent.exists( getFullPath( path ) );
+    }
+
+    @Override
+    public boolean isDirectory( @Nonnull String path ) throws IOException
+    {
+        return parent.isDirectory( getFullPath( path ) );
+    }
+
     @Override
     public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
     {
-        this.parent.list( this.getFullPath( path ), contents );
+        parent.list( getFullPath( path ), contents );
+    }
+
+    @Override
+    public long getSize( @Nonnull String path ) throws IOException
+    {
+        return parent.getSize( getFullPath( path ) );
     }
 
     @Nonnull
     @Override
     public ReadableByteChannel openForRead( @Nonnull String path ) throws IOException
     {
-        return this.parent.openForRead( this.getFullPath( path ) );
+        return parent.openForRead( getFullPath( path ) );
     }
 
     @Nonnull
     @Override
     public BasicFileAttributes getAttributes( @Nonnull String path ) throws IOException
     {
-        return this.parent.getAttributes( this.getFullPath( path ) );
-    }
-
-    @Override
-    public boolean exists( @Nonnull String path ) throws IOException
-    {
-        return this.parent.exists( this.getFullPath( path ) );
-    }
-
-    @Override
-    public boolean isDirectory( @Nonnull String path ) throws IOException
-    {
-        return this.parent.isDirectory( this.getFullPath( path ) );
-    }
-
-    @Override
-    public long getSize( @Nonnull String path ) throws IOException
-    {
-        return this.parent.getSize( this.getFullPath( path ) );
+        return parent.getAttributes( getFullPath( path ) );
     }
 
     private String getFullPath( String path )
     {
-        return path.isEmpty() ? this.subPath : this.subPath + "/" + path;
+        return path.isEmpty() ? subPath : subPath + "/" + path;
     }
 }

src/main/java/dan200/computercraft/core/lua/BasicFunction.java

@@ -45,7 +45,7 @@ class BasicFunction extends VarArgFunction
         MethodResult results;
         try
         {
-            results = this.method.apply( this.instance, this.context, arguments );
+            results = method.apply( instance, context, arguments );
         }
         catch( LuaException e )
         {
@@ -55,7 +55,7 @@ class BasicFunction extends VarArgFunction
         {
             if( ComputerCraft.logComputerErrors )
             {
-                ComputerCraft.log.error( "Error calling " + this.name + " on " + this.instance, t );
+                ComputerCraft.log.error( "Error calling " + name + " on " + instance, t );
             }
             throw new LuaError( "Java Exception Thrown: " + t, 0 );
         }
@@ -64,7 +64,7 @@ class BasicFunction extends VarArgFunction
         {
             throw new IllegalStateException( "Cannot have a yielding non-yielding function" );
         }
-        return this.machine.toValues( results.getResult() );
+        return machine.toValues( results.getResult() );
     }
 
     public static LuaError wrap( LuaException exception )

src/main/java/dan200/computercraft/core/lua/CobaltLuaMachine.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.lua;
 
 import dan200.computercraft.ComputerCraft;
@@ -11,7 +10,6 @@ import dan200.computercraft.api.lua.*;
 import dan200.computercraft.core.asm.LuaMethod;
 import dan200.computercraft.core.asm.ObjectSource;
 import dan200.computercraft.core.computer.Computer;
-import dan200.computercraft.core.computer.MainThread;
 import dan200.computercraft.core.computer.TimeoutState;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.core.tracking.TrackingField;
@@ -42,38 +40,39 @@ import static org.squiddev.cobalt.debug.DebugFrame.FLAG_HOOKYIELD;
 
 public class CobaltLuaMachine implements ILuaMachine
 {
-    private static final ThreadPoolExecutor COROUTINES = new ThreadPoolExecutor( 0,
-        Integer.MAX_VALUE,
-        5L,
-        TimeUnit.MINUTES,
+    private static final ThreadPoolExecutor COROUTINES = new ThreadPoolExecutor(
+        0, Integer.MAX_VALUE,
+        5L, TimeUnit.MINUTES,
         new SynchronousQueue<>(),
-        ThreadUtils.factory( "Coroutine" ) );
+        ThreadUtils.factory( "Coroutine" )
+    );
 
     private static final LuaMethod FUNCTION_METHOD = ( target, context, args ) -> ((ILuaFunction) target).call( args );
 
-    private final Computer m_computer;
+    private final Computer computer;
     private final TimeoutState timeout;
     private final TimeoutDebugHandler debug;
-    private final ILuaContext context = new CobaltLuaContext();
+    private final ILuaContext context;
 
-    private LuaState m_state;
-    private LuaTable m_globals;
+    private LuaState state;
+    private LuaTable globals;
 
-    private LuaThread m_mainRoutine = null;
-    private String m_eventFilter = null;
+    private LuaThread mainRoutine = null;
+    private String eventFilter = null;
 
     public CobaltLuaMachine( Computer computer, TimeoutState timeout )
     {
-        this.m_computer = computer;
+        this.computer = computer;
         this.timeout = timeout;
-        this.debug = new TimeoutDebugHandler();
+        this.context = new LuaContext( computer );
+        debug = new TimeoutDebugHandler();
 
         // Create an environment to run in
-        LuaState state = this.m_state = LuaState.builder()
+        LuaState state = this.state = LuaState.builder()
             .resourceManipulator( new VoidResourceManipulator() )
-            .debug( this.debug )
+            .debug( debug )
             .coroutineExecutor( command -> {
-                Tracking.addValue( this.m_computer, TrackingField.COROUTINES_CREATED, 1 );
+                Tracking.addValue( this.computer, TrackingField.COROUTINES_CREATED, 1 );
                 COROUTINES.execute( () -> {
                     try
                     {
@@ -81,47 +80,278 @@ public class CobaltLuaMachine implements ILuaMachine
                     }
                     finally
                     {
-                        Tracking.addValue( this.m_computer, TrackingField.COROUTINES_DISPOSED, 1 );
+                        Tracking.addValue( this.computer, TrackingField.COROUTINES_DISPOSED, 1 );
                     }
                 } );
             } )
             .build();
 
-        this.m_globals = new LuaTable();
-        state.setupThread( this.m_globals );
+        globals = new LuaTable();
+        state.setupThread( globals );
 
         // Add basic libraries
-        this.m_globals.load( state, new BaseLib() );
-        this.m_globals.load( state, new TableLib() );
-        this.m_globals.load( state, new StringLib() );
-        this.m_globals.load( state, new MathLib() );
-        this.m_globals.load( state, new CoroutineLib() );
-        this.m_globals.load( state, new Bit32Lib() );
-        this.m_globals.load( state, new Utf8Lib() );
-        if( ComputerCraft.debugEnable )
-        {
-            this.m_globals.load( state, new DebugLib() );
-        }
+        globals.load( state, new BaseLib() );
+        globals.load( state, new TableLib() );
+        globals.load( state, new StringLib() );
+        globals.load( state, new MathLib() );
+        globals.load( state, new CoroutineLib() );
+        globals.load( state, new Bit32Lib() );
+        globals.load( state, new Utf8Lib() );
+        if( ComputerCraft.debugEnable ) globals.load( state, new DebugLib() );
 
         // Remove globals we don't want to expose
-        this.m_globals.rawset( "collectgarbage", Constants.NIL );
-        this.m_globals.rawset( "dofile", Constants.NIL );
-        this.m_globals.rawset( "loadfile", Constants.NIL );
-        this.m_globals.rawset( "print", Constants.NIL );
+        globals.rawset( "collectgarbage", Constants.NIL );
+        globals.rawset( "dofile", Constants.NIL );
+        globals.rawset( "loadfile", Constants.NIL );
+        globals.rawset( "print", Constants.NIL );
 
         // Add version globals
-        this.m_globals.rawset( "_VERSION", valueOf( "Lua 5.1" ) );
-        this.m_globals.rawset( "_HOST",
-            valueOf( computer.getAPIEnvironment()
-                .getComputerEnvironment()
-                .getHostString() ) );
-        this.m_globals.rawset( "_CC_DEFAULT_SETTINGS", valueOf( ComputerCraft.defaultComputerSettings ) );
+        globals.rawset( "_VERSION", valueOf( "Lua 5.1" ) );
+        globals.rawset( "_HOST", valueOf( computer.getAPIEnvironment().getComputerEnvironment().getHostString() ) );
+        globals.rawset( "_CC_DEFAULT_SETTINGS", valueOf( ComputerCraft.defaultComputerSettings ) );
         if( ComputerCraft.disableLua51Features )
         {
-            this.m_globals.rawset( "_CC_DISABLE_LUA51_FEATURES", Constants.TRUE );
+            globals.rawset( "_CC_DISABLE_LUA51_FEATURES", Constants.TRUE );
         }
     }
 
+    @Override
+    public void addAPI( @Nonnull ILuaAPI api )
+    {
+        // Add the methods of an API to the global table
+        LuaTable table = wrapLuaObject( api );
+        if( table == null )
+        {
+            ComputerCraft.log.warn( "API {} does not provide any methods", api );
+            table = new LuaTable();
+        }
+
+        String[] names = api.getNames();
+        for( String name : names ) globals.rawset( name, table );
+    }
+
+    @Override
+    public MachineResult loadBios( @Nonnull InputStream bios )
+    {
+        // Begin executing a file (ie, the bios)
+        if( mainRoutine != null ) return MachineResult.OK;
+
+        try
+        {
+            LuaFunction value = LoadState.load( state, bios, "@bios.lua", globals );
+            mainRoutine = new LuaThread( state, value, globals );
+            return MachineResult.OK;
+        }
+        catch( CompileException e )
+        {
+            close();
+            return MachineResult.error( e );
+        }
+        catch( Exception e )
+        {
+            ComputerCraft.log.warn( "Could not load bios.lua", e );
+            close();
+            return MachineResult.GENERIC_ERROR;
+        }
+    }
+
+    @Override
+    public MachineResult handleEvent( String eventName, Object[] arguments )
+    {
+        if( mainRoutine == null ) return MachineResult.OK;
+
+        if( eventFilter != null && eventName != null && !eventName.equals( eventFilter ) && !eventName.equals( "terminate" ) )
+        {
+            return MachineResult.OK;
+        }
+
+        // If the soft abort has been cleared then we can reset our flag.
+        timeout.refresh();
+        if( !timeout.isSoftAborted() ) debug.thrownSoftAbort = false;
+
+        try
+        {
+            Varargs resumeArgs = Constants.NONE;
+            if( eventName != null )
+            {
+                resumeArgs = varargsOf( valueOf( eventName ), toValues( arguments ) );
+            }
+
+            // Resume the current thread, or the main one when first starting off.
+            LuaThread thread = state.getCurrentThread();
+            if( thread == null || thread == state.getMainThread() ) thread = mainRoutine;
+
+            Varargs results = LuaThread.run( thread, resumeArgs );
+            if( timeout.isHardAborted() ) throw HardAbortError.INSTANCE;
+            if( results == null ) return MachineResult.PAUSE;
+
+            LuaValue filter = results.first();
+            eventFilter = filter.isString() ? filter.toString() : null;
+
+            if( mainRoutine.getStatus().equals( "dead" ) )
+            {
+                close();
+                return MachineResult.GENERIC_ERROR;
+            }
+            else
+            {
+                return MachineResult.OK;
+            }
+        }
+        catch( HardAbortError | InterruptedException e )
+        {
+            close();
+            return MachineResult.TIMEOUT;
+        }
+        catch( LuaError e )
+        {
+            close();
+            ComputerCraft.log.warn( "Top level coroutine errored", e );
+            return MachineResult.error( e );
+        }
+    }
+
+    @Override
+    public void close()
+    {
+        LuaState state = this.state;
+        if( state == null ) return;
+
+        state.abandon();
+        mainRoutine = null;
+        this.state = null;
+        globals = null;
+    }
+
+    @Nullable
+    private LuaTable wrapLuaObject( Object object )
+    {
+        String[] dynamicMethods = object instanceof IDynamicLuaObject
+            ? Objects.requireNonNull( ((IDynamicLuaObject) object).getMethodNames(), "Methods cannot be null" )
+            : LuaMethod.EMPTY_METHODS;
+
+        LuaTable table = new LuaTable();
+        for( int i = 0; i < dynamicMethods.length; i++ )
+        {
+            String method = dynamicMethods[i];
+            table.rawset( method, new ResultInterpreterFunction( this, LuaMethod.DYNAMIC.get( i ), object, context, method ) );
+        }
+
+        ObjectSource.allMethods( LuaMethod.GENERATOR, object, ( instance, method ) ->
+            table.rawset( method.getName(), method.nonYielding()
+                ? new BasicFunction( this, method.getMethod(), instance, context, method.getName() )
+                : new ResultInterpreterFunction( this, method.getMethod(), instance, context, method.getName() ) ) );
+
+        try
+        {
+            if( table.keyCount() == 0 ) return null;
+        }
+        catch( LuaError ignored )
+        {
+        }
+
+        return table;
+    }
+
+    @Nonnull
+    private LuaValue toValue( @Nullable Object object, @Nullable Map<Object, LuaValue> values )
+    {
+        if( object == null ) return Constants.NIL;
+        if( object instanceof Number ) return valueOf( ((Number) object).doubleValue() );
+        if( object instanceof Boolean ) return valueOf( (Boolean) object );
+        if( object instanceof String ) return valueOf( object.toString() );
+        if( object instanceof byte[] )
+        {
+            byte[] b = (byte[]) object;
+            return valueOf( Arrays.copyOf( b, b.length ) );
+        }
+        if( object instanceof ByteBuffer )
+        {
+            ByteBuffer b = (ByteBuffer) object;
+            byte[] bytes = new byte[b.remaining()];
+            b.get( bytes );
+            return valueOf( bytes );
+        }
+
+        if( values == null ) values = new IdentityHashMap<>( 1 );
+        LuaValue result = values.get( object );
+        if( result != null ) return result;
+
+        if( object instanceof ILuaFunction )
+        {
+            return new ResultInterpreterFunction( this, FUNCTION_METHOD, object, context, object.toString() );
+        }
+
+        if( object instanceof IDynamicLuaObject )
+        {
+            LuaValue wrapped = wrapLuaObject( object );
+            if( wrapped == null ) wrapped = new LuaTable();
+            values.put( object, wrapped );
+            return wrapped;
+        }
+
+        if( object instanceof Map )
+        {
+            LuaTable table = new LuaTable();
+            values.put( object, table );
+
+            for( Map.Entry<?, ?> pair : ((Map<?, ?>) object).entrySet() )
+            {
+                LuaValue key = toValue( pair.getKey(), values );
+                LuaValue value = toValue( pair.getValue(), values );
+                if( !key.isNil() && !value.isNil() ) table.rawset( key, value );
+            }
+            return table;
+        }
+
+        if( object instanceof Collection )
+        {
+            Collection<?> objects = (Collection<?>) object;
+            LuaTable table = new LuaTable( objects.size(), 0 );
+            values.put( object, table );
+            int i = 0;
+            for( Object child : objects ) table.rawset( ++i, toValue( child, values ) );
+            return table;
+        }
+
+        if( object instanceof Object[] )
+        {
+            Object[] objects = (Object[]) object;
+            LuaTable table = new LuaTable( objects.length, 0 );
+            values.put( object, table );
+            for( int i = 0; i < objects.length; i++ ) table.rawset( i + 1, toValue( objects[i], values ) );
+            return table;
+        }
+
+        LuaTable wrapped = wrapLuaObject( object );
+        if( wrapped != null )
+        {
+            values.put( object, wrapped );
+            return wrapped;
+        }
+
+        if( ComputerCraft.logComputerErrors )
+        {
+            ComputerCraft.log.warn( "Received unknown type '{}', returning nil.", object.getClass().getName() );
+        }
+        return Constants.NIL;
+    }
+
+    Varargs toValues( Object[] objects )
+    {
+        if( objects == null || objects.length == 0 ) return Constants.NONE;
+        if( objects.length == 1 ) return toValue( objects[0], null );
+
+        Map<Object, LuaValue> result = new IdentityHashMap<>( 0 );
+        LuaValue[] values = new LuaValue[objects.length];
+        for( int i = 0; i < values.length; i++ )
+        {
+            Object object = objects[i];
+            values[i] = toValue( object, result );
+        }
+        return varargsOf( values );
+    }
+
     static Object toObject( LuaValue value, Map<LuaValue, Object> objects )
     {
         switch( value.type() )
@@ -147,10 +377,7 @@ public class CobaltLuaMachine implements ILuaMachine
                 else
                 {
                     Object existing = objects.get( value );
-                    if( existing != null )
-                    {
-                        return existing;
-                    }
+                    if( existing != null ) return existing;
                 }
                 Map<Object, Object> table = new HashMap<>();
                 objects.put( value, table );
@@ -171,10 +398,7 @@ public class CobaltLuaMachine implements ILuaMachine
                         break;
                     }
                     k = keyValue.first();
-                    if( k.isNil() )
-                    {
-                        break;
-                    }
+                    if( k.isNil() ) break;
 
                     LuaValue v = keyValue.arg( 2 );
                     Object keyObject = toObject( k, objects );
@@ -195,10 +419,7 @@ public class CobaltLuaMachine implements ILuaMachine
     {
         int count = values.count();
         Object[] objects = new Object[count];
-        for( int i = 0; i < count; i++ )
-        {
-            objects[i] = toObject( values.arg( i + 1 ), null );
-        }
+        for( int i = 0; i < count; i++ ) objects[i] = toObject( values.arg( i + 1 ), null );
         return objects;
     }
 
@@ -207,342 +428,22 @@ public class CobaltLuaMachine implements ILuaMachine
         return values == Constants.NONE ? VarargArguments.EMPTY : new VarargArguments( values );
     }
 
-    @Override
-    public void addAPI( @Nonnull ILuaAPI api )
-    {
-        // Add the methods of an API to the global table
-        LuaTable table = this.wrapLuaObject( api );
-        if( table == null )
-        {
-            ComputerCraft.log.warn( "API {} does not provide any methods", api );
-            table = new LuaTable();
-        }
-
-        String[] names = api.getNames();
-        for( String name : names )
-        {
-            this.m_globals.rawset( name, table );
-        }
-    }
-
-    @Override
-    public MachineResult loadBios( @Nonnull InputStream bios )
-    {
-        // Begin executing a file (ie, the bios)
-        if( this.m_mainRoutine != null )
-        {
-            return MachineResult.OK;
-        }
-
-        try
-        {
-            LuaFunction value = LoadState.load( this.m_state, bios, "@bios.lua", this.m_globals );
-            this.m_mainRoutine = new LuaThread( this.m_state, value, this.m_globals );
-            return MachineResult.OK;
-        }
-        catch( CompileException e )
-        {
-            this.close();
-            return MachineResult.error( e );
-        }
-        catch( Exception e )
-        {
-            ComputerCraft.log.warn( "Could not load bios.lua", e );
-            this.close();
-            return MachineResult.GENERIC_ERROR;
-        }
-    }
-
-    @Override
-    public MachineResult handleEvent( String eventName, Object[] arguments )
-    {
-        if( this.m_mainRoutine == null )
-        {
-            return MachineResult.OK;
-        }
-
-        if( this.m_eventFilter != null && eventName != null && !eventName.equals( this.m_eventFilter ) && !eventName.equals( "terminate" ) )
-        {
-            return MachineResult.OK;
-        }
-
-        // If the soft abort has been cleared then we can reset our flag.
-        this.timeout.refresh();
-        if( !this.timeout.isSoftAborted() )
-        {
-            this.debug.thrownSoftAbort = false;
-        }
-
-        try
-        {
-            Varargs resumeArgs = Constants.NONE;
-            if( eventName != null )
-            {
-                resumeArgs = varargsOf( valueOf( eventName ), this.toValues( arguments ) );
-            }
-
-            // Resume the current thread, or the main one when first starting off.
-            LuaThread thread = this.m_state.getCurrentThread();
-            if( thread == null || thread == this.m_state.getMainThread() )
-            {
-                thread = this.m_mainRoutine;
-            }
-
-            Varargs results = LuaThread.run( thread, resumeArgs );
-            if( this.timeout.isHardAborted() )
-            {
-                throw HardAbortError.INSTANCE;
-            }
-            if( results == null )
-            {
-                return MachineResult.PAUSE;
-            }
-
-            LuaValue filter = results.first();
-            this.m_eventFilter = filter.isString() ? filter.toString() : null;
-
-            if( this.m_mainRoutine.getStatus()
-                .equals( "dead" ) )
-            {
-                this.close();
-                return MachineResult.GENERIC_ERROR;
-            }
-            else
-            {
-                return MachineResult.OK;
-            }
-        }
-        catch( HardAbortError | InterruptedException e )
-        {
-            this.close();
-            return MachineResult.TIMEOUT;
-        }
-        catch( LuaError e )
-        {
-            this.close();
-            ComputerCraft.log.warn( "Top level coroutine errored", e );
-            return MachineResult.error( e );
-        }
-    }
-
-    @Override
-    public void close()
-    {
-        LuaState state = this.m_state;
-        if( state == null )
-        {
-            return;
-        }
-
-        state.abandon();
-        this.m_mainRoutine = null;
-        this.m_state = null;
-        this.m_globals = null;
-    }
-
-    @Nullable
-    private LuaTable wrapLuaObject( Object object )
-    {
-        String[] dynamicMethods = object instanceof IDynamicLuaObject ? Objects.requireNonNull( ((IDynamicLuaObject) object).getMethodNames(),
-            "Methods cannot be null" ) : LuaMethod.EMPTY_METHODS;
-
-        LuaTable table = new LuaTable();
-        for( int i = 0; i < dynamicMethods.length; i++ )
-        {
-            String method = dynamicMethods[i];
-            table.rawset( method, new ResultInterpreterFunction( this, LuaMethod.DYNAMIC.get( i ), object, this.context, method ) );
-        }
-
-        ObjectSource.allMethods( LuaMethod.GENERATOR,
-            object,
-            ( instance, method ) -> table.rawset( method.getName(),
-                method.nonYielding() ? new BasicFunction( this,
-                    (LuaMethod) method.getMethod(),
-                    instance, this.context,
-                    method.getName() ) :
-                    new ResultInterpreterFunction(
-                        this,
-                        (LuaMethod) method.getMethod(),
-                        instance, this.context,
-                        method.getName() ) ) );
-
-        try
-        {
-            if( table.keyCount() == 0 )
-            {
-                return null;
-            }
-        }
-        catch( LuaError ignored )
-        {
-        }
-
-        return table;
-    }
-
-    @Nonnull
-    private LuaValue toValue( @Nullable Object object, @Nullable Map<Object, LuaValue> values )
-    {
-        if( object == null )
-        {
-            return Constants.NIL;
-        }
-        if( object instanceof Number )
-        {
-            return valueOf( ((Number) object).doubleValue() );
-        }
-        if( object instanceof Boolean )
-        {
-            return valueOf( (Boolean) object );
-        }
-        if( object instanceof String )
-        {
-            return valueOf( object.toString() );
-        }
-        if( object instanceof byte[] )
-        {
-            byte[] b = (byte[]) object;
-            return valueOf( Arrays.copyOf( b, b.length ) );
-        }
-        if( object instanceof ByteBuffer )
-        {
-            ByteBuffer b = (ByteBuffer) object;
-            byte[] bytes = new byte[b.remaining()];
-            b.get( bytes );
-            return valueOf( bytes );
-        }
-
-        if( values == null )
-        {
-            values = new IdentityHashMap<>( 1 );
-        }
-        LuaValue result = values.get( object );
-        if( result != null )
-        {
-            return result;
-        }
-
-        if( object instanceof ILuaFunction )
-        {
-            return new ResultInterpreterFunction( this, FUNCTION_METHOD, object, this.context, object.toString() );
-        }
-
-        if( object instanceof IDynamicLuaObject )
-        {
-            LuaValue wrapped = this.wrapLuaObject( object );
-            if( wrapped == null )
-            {
-                wrapped = new LuaTable();
-            }
-            values.put( object, wrapped );
-            return wrapped;
-        }
-
-        if( object instanceof Map )
-        {
-            LuaTable table = new LuaTable();
-            values.put( object, table );
-
-            for( Map.Entry<?, ?> pair : ((Map<?, ?>) object).entrySet() )
-            {
-                LuaValue key = this.toValue( pair.getKey(), values );
-                LuaValue value = this.toValue( pair.getValue(), values );
-                if( !key.isNil() && !value.isNil() )
-                {
-                    table.rawset( key, value );
-                }
-            }
-            return table;
-        }
-
-        if( object instanceof Collection )
-        {
-            Collection<?> objects = (Collection<?>) object;
-            LuaTable table = new LuaTable( objects.size(), 0 );
-            values.put( object, table );
-            int i = 0;
-            for( Object child : objects )
-            {
-                table.rawset( ++i, this.toValue( child, values ) );
-            }
-            return table;
-        }
-
-        if( object instanceof Object[] )
-        {
-            Object[] objects = (Object[]) object;
-            LuaTable table = new LuaTable( objects.length, 0 );
-            values.put( object, table );
-            for( int i = 0; i < objects.length; i++ )
-            {
-                table.rawset( i + 1, this.toValue( objects[i], values ) );
-            }
-            return table;
-        }
-
-        LuaTable wrapped = this.wrapLuaObject( object );
-        if( wrapped != null )
-        {
-            values.put( object, wrapped );
-            return wrapped;
-        }
-
-        if( ComputerCraft.logComputerErrors )
-        {
-            ComputerCraft.log.warn( "Received unknown type '{}', returning nil.",
-                object.getClass()
-                    .getName() );
-        }
-        return Constants.NIL;
-    }
-
-    Varargs toValues( Object[] objects )
-    {
-        if( objects == null || objects.length == 0 )
-        {
-            return Constants.NONE;
-        }
-        if( objects.length == 1 )
-        {
-            return this.toValue( objects[0], null );
-        }
-
-        Map<Object, LuaValue> result = new IdentityHashMap<>( 0 );
-        LuaValue[] values = new LuaValue[objects.length];
-        for( int i = 0; i < values.length; i++ )
-        {
-            Object object = objects[i];
-            values[i] = this.toValue( object, result );
-        }
-        return varargsOf( values );
-    }
-
-    private static final class HardAbortError extends Error
-    {
-        static final HardAbortError INSTANCE = new HardAbortError();
-        private static final long serialVersionUID = 7954092008586367501L;
-
-        private HardAbortError()
-        {
-            super( "Hard Abort", null, true, false );
-        }
-    }
-
     /**
      * A {@link DebugHandler} which observes the {@link TimeoutState} and responds accordingly.
      */
     private class TimeoutDebugHandler extends DebugHandler
     {
         private final TimeoutState timeout;
-        boolean thrownSoftAbort;
         private int count = 0;
+        boolean thrownSoftAbort;
+
         private boolean isPaused;
         private int oldFlags;
         private boolean oldInHook;
 
         TimeoutDebugHandler()
         {
-            this.timeout = CobaltLuaMachine.this.timeout;
+            timeout = CobaltLuaMachine.this.timeout;
         }
 
         @Override
@@ -550,35 +451,29 @@ public class CobaltLuaMachine implements ILuaMachine
         {
             di.pc = pc;
 
-            if( this.isPaused )
-            {
-                this.resetPaused( ds, di );
-            }
+            if( isPaused ) resetPaused( ds, di );
 
             // We check our current pause/abort state every 128 instructions.
-            if( (this.count = (this.count + 1) & 127) == 0 )
+            if( (count = (count + 1) & 127) == 0 )
             {
                 // If we've been hard aborted or closed then abort.
-                if( this.timeout.isHardAborted() || CobaltLuaMachine.this.m_state == null )
-                {
-                    throw HardAbortError.INSTANCE;
-                }
+                if( timeout.isHardAborted() || state == null ) throw HardAbortError.INSTANCE;
 
-                this.timeout.refresh();
-                if( this.timeout.isPaused() )
+                timeout.refresh();
+                if( timeout.isPaused() )
                 {
                     // Preserve the current state
-                    this.isPaused = true;
-                    this.oldInHook = ds.inhook;
-                    this.oldFlags = di.flags;
+                    isPaused = true;
+                    oldInHook = ds.inhook;
+                    oldFlags = di.flags;
 
                     // Suspend the state. This will probably throw, but we need to handle the case where it won't.
                     di.flags |= FLAG_HOOKYIELD | FLAG_HOOKED;
                     LuaThread.suspend( ds.getLuaState() );
-                    this.resetPaused( ds, di );
+                    resetPaused( ds, di );
                 }
 
-                this.handleSoftAbort();
+                handleSoftAbort();
             }
 
             super.onInstruction( ds, di, pc );
@@ -588,99 +483,41 @@ public class CobaltLuaMachine implements ILuaMachine
         public void poll() throws LuaError
         {
             // If we've been hard aborted or closed then abort.
-            LuaState state = CobaltLuaMachine.this.m_state;
-            if( this.timeout.isHardAborted() || state == null )
-            {
-                throw HardAbortError.INSTANCE;
-            }
+            LuaState state = CobaltLuaMachine.this.state;
+            if( timeout.isHardAborted() || state == null ) throw HardAbortError.INSTANCE;
 
-            this.timeout.refresh();
-            if( this.timeout.isPaused() )
-            {
-                LuaThread.suspendBlocking( state );
-            }
-            this.handleSoftAbort();
+            timeout.refresh();
+            if( timeout.isPaused() ) LuaThread.suspendBlocking( state );
+            handleSoftAbort();
         }
 
         private void resetPaused( DebugState ds, DebugFrame di )
         {
             // Restore the previous paused state
-            this.isPaused = false;
-            ds.inhook = this.oldInHook;
-            di.flags = this.oldFlags;
+            isPaused = false;
+            ds.inhook = oldInHook;
+            di.flags = oldFlags;
         }
 
         private void handleSoftAbort() throws LuaError
         {
             // If we already thrown our soft abort error then don't do it again.
-            if( !this.timeout.isSoftAborted() || this.thrownSoftAbort )
-            {
-                return;
-            }
+            if( !timeout.isSoftAborted() || thrownSoftAbort ) return;
 
-            this.thrownSoftAbort = true;
+            thrownSoftAbort = true;
             throw new LuaError( TimeoutState.ABORT_MESSAGE );
         }
     }
 
-    private class CobaltLuaContext implements ILuaContext
+    private static final class HardAbortError extends Error
     {
-        @Override
-        public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
+        private static final long serialVersionUID = 7954092008586367501L;
+
+        static final HardAbortError INSTANCE = new HardAbortError();
+
+        private HardAbortError()
         {
-            // Issue command
-            final long taskID = MainThread.getUniqueTaskID();
-            final Runnable iTask = () -> {
-                try
-                {
-                    Object[] results = task.execute();
-                    if( results != null )
-                    {
-                        Object[] eventArguments = new Object[results.length + 2];
-                        eventArguments[0] = taskID;
-                        eventArguments[1] = true;
-                        System.arraycopy( results, 0, eventArguments, 2, results.length );
-                        CobaltLuaMachine.this.m_computer.queueEvent( "task_complete", eventArguments );
-                    }
-                    else
-                    {
-                        CobaltLuaMachine.this.m_computer.queueEvent( "task_complete",
-                            new Object[] {
-                                taskID,
-                                true
-                            } );
-                    }
-                }
-                catch( LuaException e )
-                {
-                    CobaltLuaMachine.this.m_computer.queueEvent( "task_complete",
-                        new Object[] {
-                            taskID,
-                            false,
-                            e.getMessage()
-                        } );
-                }
-                catch( Throwable t )
-                {
-                    if( ComputerCraft.logComputerErrors )
-                    {
-                        ComputerCraft.log.error( "Error running task", t );
-                    }
-                    CobaltLuaMachine.this.m_computer.queueEvent( "task_complete", new Object[] {
-                        taskID,
-                        false,
-                        "Java Exception Thrown: " + t,
-                    } );
-                }
-            };
-            if( CobaltLuaMachine.this.m_computer.queueMainThread( iTask ) )
-            {
-                return taskID;
-            }
-            else
-            {
-                throw new LuaException( "Task limit exceeded" );
-            }
+            super( "Hard Abort", null, true, false );
         }
     }
 }

src/main/java/dan200/computercraft/core/lua/ILuaMachine.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.lua;
 
 import dan200.computercraft.api.lua.IDynamicLuaObject;
@@ -14,20 +13,21 @@ import javax.annotation.Nullable;
 import java.io.InputStream;
 
 /**
- * Represents a machine which will execute Lua code. Technically this API is flexible enough to support many languages, but you'd need a way to provide
- * alternative ROMs, BIOSes, etc...
+ * Represents a machine which will execute Lua code. Technically this API is flexible enough to support many languages,
+ * but you'd need a way to provide alternative ROMs, BIOSes, etc...
  *
- * There should only be one concrete implementation at any one time, which is currently {@link CobaltLuaMachine}. If external mod authors are interested in
- * registering their own machines, we can look into how we can provide some mechanism for registering these.
+ * There should only be one concrete implementation at any one time, which is currently {@link CobaltLuaMachine}. If
+ * external mod authors are interested in registering their own machines, we can look into how we can provide some
+ * mechanism for registering these.
  *
- * This should provide implementations of {@link dan200.computercraft.api.lua.ILuaContext}, and the ability to convert {@link IDynamicLuaObject}s into
- * something the VM understands, as well as handling method calls.
+ * This should provide implementations of {@link dan200.computercraft.api.lua.ILuaContext}, and the ability to convert
+ * {@link IDynamicLuaObject}s into something the VM understands, as well as handling method calls.
  */
 public interface ILuaMachine
 {
     /**
-     * Inject an API into the global environment of this machine. This should construct an object, as it would for any {@link IDynamicLuaObject} and set it
-     * to all names in {@link ILuaAPI#getNames()}.
+     * Inject an API into the global environment of this machine. This should construct an object, as it would for any
+     * {@link IDynamicLuaObject} and set it to all names in {@link ILuaAPI#getNames()}.
      *
      * Called before {@link #loadBios(InputStream)}.
      *
@@ -36,7 +36,8 @@ public interface ILuaMachine
     void addAPI( @Nonnull ILuaAPI api );
 
     /**
-     * Create a function from the provided program, and set it up to run when {@link #handleEvent(String, Object[])} is called.
+     * Create a function from the provided program, and set it up to run when {@link #handleEvent(String, Object[])} is
+     * called.
      *
      * This should destroy the machine if it failed to load the bios.
      *
@@ -50,10 +51,11 @@ public interface ILuaMachine
      *
      * This should destroy the machine if it failed to execute successfully.
      *
-     * @param eventName The name of the event. This is {@code null} when first starting the machine. Note, this may do nothing if it does not match the
-     *                  event filter.
+     * @param eventName The name of the event. This is {@code null} when first starting the machine. Note, this may
+     *                  do nothing if it does not match the event filter.
      * @param arguments The arguments for this event.
-     * @return The result of loading this machine. Will either be OK, or the error message that occurred when executing.
+     * @return The result of loading this machine. Will either be OK, or the error message that occurred when
+     * executing.
      */
     MachineResult handleEvent( @Nullable String eventName, @Nullable Object[] arguments );
 

src/main/java/dan200/computercraft/core/lua/LuaContext.java

@@ -0,0 +1,69 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.core.lua;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.ILuaTask;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.MainThread;
+
+import javax.annotation.Nonnull;
+
+class LuaContext implements ILuaContext
+{
+    private final Computer computer;
+
+    LuaContext( Computer computer )
+    {
+        this.computer = computer;
+    }
+
+    @Override
+    public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
+    {
+        // Issue command
+        final long taskID = MainThread.getUniqueTaskID();
+        final Runnable iTask = () -> {
+            try
+            {
+                Object[] results = task.execute();
+                if( results != null )
+                {
+                    Object[] eventArguments = new Object[results.length + 2];
+                    eventArguments[0] = taskID;
+                    eventArguments[1] = true;
+                    System.arraycopy( results, 0, eventArguments, 2, results.length );
+                    computer.queueEvent( "task_complete", eventArguments );
+                }
+                else
+                {
+                    computer.queueEvent( "task_complete", new Object[] { taskID, true } );
+                }
+            }
+            catch( LuaException e )
+            {
+                computer.queueEvent( "task_complete", new Object[] { taskID, false, e.getMessage() } );
+            }
+            catch( Exception t )
+            {
+                if( ComputerCraft.logComputerErrors ) ComputerCraft.log.error( "Error running task", t );
+                computer.queueEvent( "task_complete", new Object[] {
+                    taskID, false, "Java Exception Thrown: " + t,
+                } );
+            }
+        };
+        if( computer.queueMainThread( iTask ) )
+        {
+            return taskID;
+        }
+        else
+        {
+            throw new LuaException( "Task limit exceeded" );
+        }
+    }
+}

src/main/java/dan200/computercraft/core/lua/MachineResult.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.lua;
 
 import dan200.computercraft.core.computer.TimeoutState;
@@ -65,17 +64,17 @@ public final class MachineResult
 
     public boolean isError()
     {
-        return this.error;
+        return error;
     }
 
     public boolean isPause()
     {
-        return this.pause;
+        return pause;
     }
 
     @Nullable
     public String getMessage()
     {
-        return this.message;
+        return message;
     }
 }

src/main/java/dan200/computercraft/core/lua/ResultInterpreterFunction.java

@@ -15,11 +15,24 @@ import org.squiddev.cobalt.function.ResumableVarArgFunction;
 import javax.annotation.Nonnull;
 
 /**
- * Calls a {@link LuaMethod}, and interprets the resulting {@link MethodResult}, either returning the result or yielding and resuming the supplied
- * continuation.
+ * Calls a {@link LuaMethod}, and interprets the resulting {@link MethodResult}, either returning the result or yielding
+ * and resuming the supplied continuation.
  */
 class ResultInterpreterFunction extends ResumableVarArgFunction<ResultInterpreterFunction.Container>
 {
+    @Nonnull
+    static class Container
+    {
+        ILuaCallback callback;
+        int errorAdjust;
+
+        Container( ILuaCallback callback, int errorAdjust )
+        {
+            this.callback = callback;
+            this.errorAdjust = errorAdjust;
+        }
+    }
+
     private final CobaltLuaMachine machine;
     private final LuaMethod method;
     private final Object instance;
@@ -42,7 +55,7 @@ class ResultInterpreterFunction extends ResumableVarArgFunction<ResultInterprete
         MethodResult results;
         try
         {
-            results = this.method.apply( this.instance, this.context, arguments );
+            results = method.apply( instance, context, arguments );
         }
         catch( LuaException e )
         {
@@ -52,18 +65,15 @@ class ResultInterpreterFunction extends ResumableVarArgFunction<ResultInterprete
         {
             if( ComputerCraft.logComputerErrors )
             {
-                ComputerCraft.log.error( "Error calling " + this.name + " on " + this.instance, t );
+                ComputerCraft.log.error( "Error calling " + name + " on " + instance, t );
             }
             throw new LuaError( "Java Exception Thrown: " + t, 0 );
         }
 
         ILuaCallback callback = results.getCallback();
-        Varargs ret = this.machine.toValues( results.getResult() );
+        Varargs ret = machine.toValues( results.getResult() );
 
-        if( callback == null )
-        {
-            return ret;
-        }
+        if( callback == null ) return ret;
 
         debugFrame.state = new Container( callback, results.getErrorAdjust() );
         return LuaThread.yield( state, ret );
@@ -86,18 +96,15 @@ class ResultInterpreterFunction extends ResumableVarArgFunction<ResultInterprete
         {
             if( ComputerCraft.logComputerErrors )
             {
-                ComputerCraft.log.error( "Error calling " + this.name + " on " + container.callback, t );
+                ComputerCraft.log.error( "Error calling " + name + " on " + container.callback, t );
             }
             throw new LuaError( "Java Exception Thrown: " + t, 0 );
         }
 
-        Varargs ret = this.machine.toValues( results.getResult() );
+        Varargs ret = machine.toValues( results.getResult() );
 
         ILuaCallback callback = results.getCallback();
-        if( callback == null )
-        {
-            return ret;
-        }
+        if( callback == null ) return ret;
 
         container.callback = callback;
         return LuaThread.yield( state, ret );
@@ -105,25 +112,9 @@ class ResultInterpreterFunction extends ResumableVarArgFunction<ResultInterprete
 
     public static LuaError wrap( LuaException exception, int adjust )
     {
-        if( !exception.hasLevel() && adjust == 0 )
-        {
-            return new LuaError( exception.getMessage() );
-        }
+        if( !exception.hasLevel() && adjust == 0 ) return new LuaError( exception.getMessage() );
 
         int level = exception.getLevel();
         return new LuaError( exception.getMessage(), level <= 0 ? level : level + adjust + 1 );
     }
-
-    @Nonnull
-    static class Container
-    {
-        ILuaCallback callback;
-        int errorAdjust;
-
-        Container( ILuaCallback callback, int errorAdjust )
-        {
-            this.callback = callback;
-            this.errorAdjust = errorAdjust;
-        }
-    }
 }

src/main/java/dan200/computercraft/core/lua/VarargArguments.java

@@ -27,104 +27,75 @@ class VarargArguments implements IArguments
         this.varargs = varargs;
     }
 
-    @Override
-    public IArguments drop( int count )
-    {
-        if( count < 0 )
-        {
-            throw new IllegalStateException( "count cannot be negative" );
-        }
-        if( count == 0 )
-        {
-            return this;
-        }
-        return new VarargArguments( this.varargs.subargs( count + 1 ) );
-    }
-
     @Override
     public int count()
     {
-        return this.varargs.count();
+        return varargs.count();
     }
 
     @Nullable
     @Override
     public Object get( int index )
     {
-        if( index < 0 || index >= this.varargs.count() )
-        {
-            return null;
-        }
+        if( index < 0 || index >= varargs.count() ) return null;
 
         Object[] cache = this.cache;
         if( cache == null )
         {
-            cache = this.cache = new Object[this.varargs.count()];
+            cache = this.cache = new Object[varargs.count()];
         }
         else
         {
             Object existing = cache[index];
-            if( existing != null )
-            {
-                return existing;
-            }
+            if( existing != null ) return existing;
         }
 
-        return cache[index] = CobaltLuaMachine.toObject( this.varargs.arg( index + 1 ), null );
+        return cache[index] = CobaltLuaMachine.toObject( varargs.arg( index + 1 ), null );
     }
 
     @Override
-    public long getLong( int index ) throws LuaException
+    public IArguments drop( int count )
     {
-        LuaValue value = this.varargs.arg( index + 1 );
-        if( !(value instanceof LuaNumber) )
-        {
-            throw LuaValues.badArgument( index, "number", value.typeName() );
-        }
-        return value instanceof LuaInteger ? value.toInteger() : (long) LuaValues.checkFinite( index, value.toDouble() );
+        if( count < 0 ) throw new IllegalStateException( "count cannot be negative" );
+        if( count == 0 ) return this;
+        return new VarargArguments( varargs.subargs( count + 1 ) );
     }
 
     @Override
     public double getDouble( int index ) throws LuaException
     {
-        LuaValue value = this.varargs.arg( index + 1 );
-        if( !(value instanceof LuaNumber) )
-        {
-            throw LuaValues.badArgument( index, "number", value.typeName() );
-        }
+        LuaValue value = varargs.arg( index + 1 );
+        if( !(value instanceof LuaNumber) ) throw LuaValues.badArgument( index, "number", value.typeName() );
         return value.toDouble();
     }
 
+    @Override
+    public long getLong( int index ) throws LuaException
+    {
+        LuaValue value = varargs.arg( index + 1 );
+        if( !(value instanceof LuaNumber) ) throw LuaValues.badArgument( index, "number", value.typeName() );
+        return value instanceof LuaInteger ? value.toInteger() : (long) LuaValues.checkFinite( index, value.toDouble() );
+    }
+
     @Nonnull
     @Override
     public ByteBuffer getBytes( int index ) throws LuaException
     {
-        LuaValue value = this.varargs.arg( index + 1 );
-        if( !(value instanceof LuaBaseString) )
-        {
-            throw LuaValues.badArgument( index, "string", value.typeName() );
-        }
+        LuaValue value = varargs.arg( index + 1 );
+        if( !(value instanceof LuaBaseString) ) throw LuaValues.badArgument( index, "string", value.typeName() );
 
         LuaString str = ((LuaBaseString) value).strvalue();
-        return ByteBuffer.wrap( str.bytes, str.offset, str.length )
-            .asReadOnlyBuffer();
+        return ByteBuffer.wrap( str.bytes, str.offset, str.length ).asReadOnlyBuffer();
     }
 
     @Override
     public Optional<ByteBuffer> optBytes( int index ) throws LuaException
     {
-        LuaValue value = this.varargs.arg( index + 1 );
-        if( value.isNil() )
-        {
-            return Optional.empty();
-        }
-        if( !(value instanceof LuaBaseString) )
-        {
-            throw LuaValues.badArgument( index, "string", value.typeName() );
-        }
+        LuaValue value = varargs.arg( index + 1 );
+        if( value.isNil() ) return Optional.empty();
+        if( !(value instanceof LuaBaseString) ) throw LuaValues.badArgument( index, "string", value.typeName() );
 
         LuaString str = ((LuaBaseString) value).strvalue();
-        return Optional.of( ByteBuffer.wrap( str.bytes, str.offset, str.length )
-            .asReadOnlyBuffer() );
+        return Optional.of( ByteBuffer.wrap( str.bytes, str.offset, str.length ).asReadOnlyBuffer() );
     }
 }

src/main/java/dan200/computercraft/core/terminal/Terminal.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.terminal;
 
 import dan200.computercraft.shared.util.Colour;
@@ -16,18 +15,23 @@ import javax.annotation.Nonnull;
 public class Terminal
 {
     private static final String base16 = "0123456789abcdef";
-    private final Palette m_palette = new Palette();
+
+    private int cursorX = 0;
+    private int cursorY = 0;
+    private boolean cursorBlink = false;
+    private int cursorColour = 0;
+    private int cursorBackgroundColour = 15;
+
+    private int width;
+    private int height;
+
+    private TextBuffer[] text;
+    private TextBuffer[] textColour;
+    private TextBuffer[] backgroundColour;
+
+    private final Palette palette = new Palette();
+
     private final Runnable onChanged;
-    private int m_cursorX = 0;
-    private int m_cursorY = 0;
-    private boolean m_cursorBlink = false;
-    private int m_cursorColour = 0;
-    private int m_cursorBackgroundColour = 15;
-    private int m_width;
-    private int m_height;
-    private TextBuffer[] m_text;
-    private TextBuffer[] m_textColour;
-    private TextBuffer[] m_backgroundColour;
 
     public Terminal( int width, int height )
     {
@@ -36,199 +40,180 @@ public class Terminal
 
     public Terminal( int width, int height, Runnable changedCallback )
     {
-        this.m_width = width;
-        this.m_height = height;
-        this.onChanged = changedCallback;
+        this.width = width;
+        this.height = height;
+        onChanged = changedCallback;
 
-        this.m_text = new TextBuffer[this.m_height];
-        this.m_textColour = new TextBuffer[this.m_height];
-        this.m_backgroundColour = new TextBuffer[this.m_height];
-        for( int i = 0; i < this.m_height; i++ )
+        text = new TextBuffer[this.height];
+        textColour = new TextBuffer[this.height];
+        backgroundColour = new TextBuffer[this.height];
+        for( int i = 0; i < this.height; i++ )
         {
-            this.m_text[i] = new TextBuffer( ' ', this.m_width );
-            this.m_textColour[i] = new TextBuffer( base16.charAt( this.m_cursorColour ), this.m_width );
-            this.m_backgroundColour[i] = new TextBuffer( base16.charAt( this.m_cursorBackgroundColour ), this.m_width );
+            text[i] = new TextBuffer( ' ', this.width );
+            textColour[i] = new TextBuffer( base16.charAt( cursorColour ), this.width );
+            backgroundColour[i] = new TextBuffer( base16.charAt( cursorBackgroundColour ), this.width );
         }
     }
 
     public synchronized void reset()
     {
-        this.m_cursorColour = 0;
-        this.m_cursorBackgroundColour = 15;
-        this.m_cursorX = 0;
-        this.m_cursorY = 0;
-        this.m_cursorBlink = false;
-        this.clear();
-        this.setChanged();
-        this.m_palette.resetColours();
-    }
-
-    public synchronized void clear()
-    {
-        for( int y = 0; y < this.m_height; y++ )
-        {
-            this.m_text[y].fill( ' ' );
-            this.m_textColour[y].fill( base16.charAt( this.m_cursorColour ) );
-            this.m_backgroundColour[y].fill( base16.charAt( this.m_cursorBackgroundColour ) );
-        }
-        this.setChanged();
-    }
-
-    public final void setChanged()
-    {
-        if( this.onChanged != null )
-        {
-            this.onChanged.run();
-        }
+        cursorColour = 0;
+        cursorBackgroundColour = 15;
+        cursorX = 0;
+        cursorY = 0;
+        cursorBlink = false;
+        clear();
+        setChanged();
+        palette.resetColours();
     }
 
     public int getWidth()
     {
-        return this.m_width;
+        return width;
     }
 
     public int getHeight()
     {
-        return this.m_height;
+        return height;
     }
 
     public synchronized void resize( int width, int height )
     {
-        if( width == this.m_width && height == this.m_height )
+        if( width == this.width && height == this.height )
         {
             return;
         }
 
-        int oldHeight = this.m_height;
-        int oldWidth = this.m_width;
-        TextBuffer[] oldText = this.m_text;
-        TextBuffer[] oldTextColour = this.m_textColour;
-        TextBuffer[] oldBackgroundColour = this.m_backgroundColour;
+        int oldHeight = this.height;
+        int oldWidth = this.width;
+        TextBuffer[] oldText = text;
+        TextBuffer[] oldTextColour = textColour;
+        TextBuffer[] oldBackgroundColour = backgroundColour;
 
-        this.m_width = width;
-        this.m_height = height;
+        this.width = width;
+        this.height = height;
 
-        this.m_text = new TextBuffer[this.m_height];
-        this.m_textColour = new TextBuffer[this.m_height];
-        this.m_backgroundColour = new TextBuffer[this.m_height];
-        for( int i = 0; i < this.m_height; i++ )
+        text = new TextBuffer[this.height];
+        textColour = new TextBuffer[this.height];
+        backgroundColour = new TextBuffer[this.height];
+        for( int i = 0; i < this.height; i++ )
         {
             if( i >= oldHeight )
             {
-                this.m_text[i] = new TextBuffer( ' ', this.m_width );
-                this.m_textColour[i] = new TextBuffer( base16.charAt( this.m_cursorColour ), this.m_width );
-                this.m_backgroundColour[i] = new TextBuffer( base16.charAt( this.m_cursorBackgroundColour ), this.m_width );
+                text[i] = new TextBuffer( ' ', this.width );
+                textColour[i] = new TextBuffer( base16.charAt( cursorColour ), this.width );
+                backgroundColour[i] = new TextBuffer( base16.charAt( cursorBackgroundColour ), this.width );
             }
-            else if( this.m_width == oldWidth )
+            else if( this.width == oldWidth )
             {
-                this.m_text[i] = oldText[i];
-                this.m_textColour[i] = oldTextColour[i];
-                this.m_backgroundColour[i] = oldBackgroundColour[i];
+                text[i] = oldText[i];
+                textColour[i] = oldTextColour[i];
+                backgroundColour[i] = oldBackgroundColour[i];
             }
             else
             {
-                this.m_text[i] = new TextBuffer( ' ', this.m_width );
-                this.m_textColour[i] = new TextBuffer( base16.charAt( this.m_cursorColour ), this.m_width );
-                this.m_backgroundColour[i] = new TextBuffer( base16.charAt( this.m_cursorBackgroundColour ), this.m_width );
-                this.m_text[i].write( oldText[i] );
-                this.m_textColour[i].write( oldTextColour[i] );
-                this.m_backgroundColour[i].write( oldBackgroundColour[i] );
+                text[i] = new TextBuffer( ' ', this.width );
+                textColour[i] = new TextBuffer( base16.charAt( cursorColour ), this.width );
+                backgroundColour[i] = new TextBuffer( base16.charAt( cursorBackgroundColour ), this.width );
+                text[i].write( oldText[i] );
+                textColour[i].write( oldTextColour[i] );
+                backgroundColour[i].write( oldBackgroundColour[i] );
             }
         }
-        this.setChanged();
+        setChanged();
     }
 
     public void setCursorPos( int x, int y )
     {
-        if( this.m_cursorX != x || this.m_cursorY != y )
+        if( cursorX != x || cursorY != y )
         {
-            this.m_cursorX = x;
-            this.m_cursorY = y;
-            this.setChanged();
+            cursorX = x;
+            cursorY = y;
+            setChanged();
+        }
+    }
+
+    public void setCursorBlink( boolean blink )
+    {
+        if( cursorBlink != blink )
+        {
+            cursorBlink = blink;
+            setChanged();
+        }
+    }
+
+    public void setTextColour( int colour )
+    {
+        if( cursorColour != colour )
+        {
+            cursorColour = colour;
+            setChanged();
+        }
+    }
+
+    public void setBackgroundColour( int colour )
+    {
+        if( cursorBackgroundColour != colour )
+        {
+            cursorBackgroundColour = colour;
+            setChanged();
         }
     }
 
     public int getCursorX()
     {
-        return this.m_cursorX;
+        return cursorX;
     }
 
     public int getCursorY()
     {
-        return this.m_cursorY;
+        return cursorY;
     }
 
     public boolean getCursorBlink()
     {
-        return this.m_cursorBlink;
-    }
-
-    public void setCursorBlink( boolean blink )
-    {
-        if( this.m_cursorBlink != blink )
-        {
-            this.m_cursorBlink = blink;
-            this.setChanged();
-        }
+        return cursorBlink;
     }
 
     public int getTextColour()
     {
-        return this.m_cursorColour;
-    }
-
-    public void setTextColour( int colour )
-    {
-        if( this.m_cursorColour != colour )
-        {
-            this.m_cursorColour = colour;
-            this.setChanged();
-        }
+        return cursorColour;
     }
 
     public int getBackgroundColour()
     {
-        return this.m_cursorBackgroundColour;
-    }
-
-    public void setBackgroundColour( int colour )
-    {
-        if( this.m_cursorBackgroundColour != colour )
-        {
-            this.m_cursorBackgroundColour = colour;
-            this.setChanged();
-        }
+        return cursorBackgroundColour;
     }
 
     @Nonnull
     public Palette getPalette()
     {
-        return this.m_palette;
+        return palette;
     }
 
     public synchronized void blit( String text, String textColour, String backgroundColour )
     {
-        int x = this.m_cursorX;
-        int y = this.m_cursorY;
-        if( y >= 0 && y < this.m_height )
+        int x = cursorX;
+        int y = cursorY;
+        if( y >= 0 && y < height )
         {
-            this.m_text[y].write( text, x );
-            this.m_textColour[y].write( textColour, x );
-            this.m_backgroundColour[y].write( backgroundColour, x );
-            this.setChanged();
+            this.text[y].write( text, x );
+            this.textColour[y].write( textColour, x );
+            this.backgroundColour[y].write( backgroundColour, x );
+            setChanged();
         }
     }
 
     public synchronized void write( String text )
     {
-        int x = this.m_cursorX;
-        int y = this.m_cursorY;
-        if( y >= 0 && y < this.m_height )
+        int x = cursorX;
+        int y = cursorY;
+        if( y >= 0 && y < height )
         {
-            this.m_text[y].write( text, x );
-            this.m_textColour[y].fill( base16.charAt( this.m_cursorColour ), x, x + text.length() );
-            this.m_backgroundColour[y].fill( base16.charAt( this.m_cursorBackgroundColour ), x, x + text.length() );
-            this.setChanged();
+            this.text[y].write( text, x );
+            textColour[y].fill( base16.charAt( cursorColour ), x, x + text.length() );
+            backgroundColour[y].fill( base16.charAt( cursorBackgroundColour ), x, x + text.length() );
+            setChanged();
         }
     }
 
@@ -236,132 +221,138 @@ public class Terminal
     {
         if( yDiff != 0 )
         {
-            TextBuffer[] newText = new TextBuffer[this.m_height];
-            TextBuffer[] newTextColour = new TextBuffer[this.m_height];
-            TextBuffer[] newBackgroundColour = new TextBuffer[this.m_height];
-            for( int y = 0; y < this.m_height; y++ )
+            TextBuffer[] newText = new TextBuffer[height];
+            TextBuffer[] newTextColour = new TextBuffer[height];
+            TextBuffer[] newBackgroundColour = new TextBuffer[height];
+            for( int y = 0; y < height; y++ )
             {
                 int oldY = y + yDiff;
-                if( oldY >= 0 && oldY < this.m_height )
+                if( oldY >= 0 && oldY < height )
                 {
-                    newText[y] = this.m_text[oldY];
-                    newTextColour[y] = this.m_textColour[oldY];
-                    newBackgroundColour[y] = this.m_backgroundColour[oldY];
+                    newText[y] = text[oldY];
+                    newTextColour[y] = textColour[oldY];
+                    newBackgroundColour[y] = backgroundColour[oldY];
                 }
                 else
                 {
-                    newText[y] = new TextBuffer( ' ', this.m_width );
-                    newTextColour[y] = new TextBuffer( base16.charAt( this.m_cursorColour ), this.m_width );
-                    newBackgroundColour[y] = new TextBuffer( base16.charAt( this.m_cursorBackgroundColour ), this.m_width );
+                    newText[y] = new TextBuffer( ' ', width );
+                    newTextColour[y] = new TextBuffer( base16.charAt( cursorColour ), width );
+                    newBackgroundColour[y] = new TextBuffer( base16.charAt( cursorBackgroundColour ), width );
                 }
             }
-            this.m_text = newText;
-            this.m_textColour = newTextColour;
-            this.m_backgroundColour = newBackgroundColour;
-            this.setChanged();
+            text = newText;
+            textColour = newTextColour;
+            backgroundColour = newBackgroundColour;
+            setChanged();
         }
     }
 
+    public synchronized void clear()
+    {
+        for( int y = 0; y < height; y++ )
+        {
+            text[y].fill( ' ' );
+            textColour[y].fill( base16.charAt( cursorColour ) );
+            backgroundColour[y].fill( base16.charAt( cursorBackgroundColour ) );
+        }
+        setChanged();
+    }
+
     public synchronized void clearLine()
     {
-        int y = this.m_cursorY;
-        if( y >= 0 && y < this.m_height )
+        int y = cursorY;
+        if( y >= 0 && y < height )
         {
-            this.m_text[y].fill( ' ' );
-            this.m_textColour[y].fill( base16.charAt( this.m_cursorColour ) );
-            this.m_backgroundColour[y].fill( base16.charAt( this.m_cursorBackgroundColour ) );
-            this.setChanged();
+            text[y].fill( ' ' );
+            textColour[y].fill( base16.charAt( cursorColour ) );
+            backgroundColour[y].fill( base16.charAt( cursorBackgroundColour ) );
+            setChanged();
         }
     }
 
     public synchronized TextBuffer getLine( int y )
     {
-        if( y >= 0 && y < this.m_height )
+        if( y >= 0 && y < height )
         {
-            return this.m_text[y];
+            return text[y];
         }
         return null;
     }
 
     public synchronized void setLine( int y, String text, String textColour, String backgroundColour )
     {
-        this.m_text[y].write( text );
-        this.m_textColour[y].write( textColour );
-        this.m_backgroundColour[y].write( backgroundColour );
-        this.setChanged();
+        this.text[y].write( text );
+        this.textColour[y].write( textColour );
+        this.backgroundColour[y].write( backgroundColour );
+        setChanged();
     }
 
     public synchronized TextBuffer getTextColourLine( int y )
     {
-        if( y >= 0 && y < this.m_height )
+        if( y >= 0 && y < height )
         {
-            return this.m_textColour[y];
+            return textColour[y];
         }
         return null;
     }
 
     public synchronized TextBuffer getBackgroundColourLine( int y )
     {
-        if( y >= 0 && y < this.m_height )
+        if( y >= 0 && y < height )
         {
-            return this.m_backgroundColour[y];
+            return backgroundColour[y];
         }
         return null;
     }
 
+    public final void setChanged()
+    {
+        if( onChanged != null ) onChanged.run();
+    }
+
     public synchronized void write( PacketByteBuf buffer )
     {
-        buffer.writeInt( this.m_cursorX );
-        buffer.writeInt( this.m_cursorY );
-        buffer.writeBoolean( this.m_cursorBlink );
-        buffer.writeByte( this.m_cursorBackgroundColour << 4 | this.m_cursorColour );
+        buffer.writeInt( cursorX );
+        buffer.writeInt( cursorY );
+        buffer.writeBoolean( cursorBlink );
+        buffer.writeByte( cursorBackgroundColour << 4 | cursorColour );
 
-        for( int y = 0; y < this.m_height; y++ )
+        for( int y = 0; y < height; y++ )
         {
-            TextBuffer text = this.m_text[y];
-            TextBuffer textColour = this.m_textColour[y];
-            TextBuffer backColour = this.m_backgroundColour[y];
+            TextBuffer text = this.text[y];
+            TextBuffer textColour = this.textColour[y];
+            TextBuffer backColour = backgroundColour[y];
 
-            for( int x = 0; x < this.m_width; x++ )
+            for( int x = 0; x < width; x++ )
             {
                 buffer.writeByte( text.charAt( x ) & 0xFF );
-                buffer.writeByte( getColour( backColour.charAt( x ), Colour.BLACK ) << 4 | getColour( textColour.charAt( x ), Colour.WHITE ) );
+                buffer.writeByte( getColour(
+                    backColour.charAt( x ), Colour.BLACK ) << 4 |
+                    getColour( textColour.charAt( x ), Colour.WHITE )
+                );
             }
         }
 
-        this.m_palette.write( buffer );
-    }
-
-    public static int getColour( char c, Colour def )
-    {
-        if( c >= '0' && c <= '9' )
-        {
-            return c - '0';
-        }
-        if( c >= 'a' && c <= 'f' )
-        {
-            return c - 'a' + 10;
-        }
-        return 15 - def.ordinal();
+        palette.write( buffer );
     }
 
     public synchronized void read( PacketByteBuf buffer )
     {
-        this.m_cursorX = buffer.readInt();
-        this.m_cursorY = buffer.readInt();
-        this.m_cursorBlink = buffer.readBoolean();
+        cursorX = buffer.readInt();
+        cursorY = buffer.readInt();
+        cursorBlink = buffer.readBoolean();
 
         byte cursorColour = buffer.readByte();
-        this.m_cursorBackgroundColour = (cursorColour >> 4) & 0xF;
-        this.m_cursorColour = cursorColour & 0xF;
+        cursorBackgroundColour = (cursorColour >> 4) & 0xF;
+        this.cursorColour = cursorColour & 0xF;
 
-        for( int y = 0; y < this.m_height; y++ )
+        for( int y = 0; y < height; y++ )
         {
-            TextBuffer text = this.m_text[y];
-            TextBuffer textColour = this.m_textColour[y];
-            TextBuffer backColour = this.m_backgroundColour[y];
+            TextBuffer text = this.text[y];
+            TextBuffer textColour = this.textColour[y];
+            TextBuffer backColour = backgroundColour[y];
 
-            for( int x = 0; x < this.m_width; x++ )
+            for( int x = 0; x < width; x++ )
             {
                 text.setChar( x, (char) (buffer.readByte() & 0xFF) );
 
@@ -371,56 +362,63 @@ public class Terminal
             }
         }
 
-        this.m_palette.read( buffer );
-        this.setChanged();
+        palette.read( buffer );
+        setChanged();
     }
 
     public synchronized CompoundTag writeToNBT( CompoundTag nbt )
     {
-        nbt.putInt( "term_cursorX", this.m_cursorX );
-        nbt.putInt( "term_cursorY", this.m_cursorY );
-        nbt.putBoolean( "term_cursorBlink", this.m_cursorBlink );
-        nbt.putInt( "term_textColour", this.m_cursorColour );
-        nbt.putInt( "term_bgColour", this.m_cursorBackgroundColour );
-        for( int n = 0; n < this.m_height; n++ )
+        nbt.putInt( "term_cursorX", cursorX );
+        nbt.putInt( "term_cursorY", cursorY );
+        nbt.putBoolean( "term_cursorBlink", cursorBlink );
+        nbt.putInt( "term_textColour", cursorColour );
+        nbt.putInt( "term_bgColour", cursorBackgroundColour );
+        for( int n = 0; n < height; n++ )
         {
-            nbt.putString( "term_text_" + n, this.m_text[n].toString() );
-            nbt.putString( "term_textColour_" + n, this.m_textColour[n].toString() );
-            nbt.putString( "term_textBgColour_" + n, this.m_backgroundColour[n].toString() );
+            nbt.putString( "term_text_" + n, text[n].toString() );
+            nbt.putString( "term_textColour_" + n, textColour[n].toString() );
+            nbt.putString( "term_textBgColour_" + n, backgroundColour[n].toString() );
         }
 
-        this.m_palette.writeToNBT( nbt );
+        palette.writeToNBT( nbt );
         return nbt;
     }
 
     public synchronized void readFromNBT( CompoundTag nbt )
     {
-        this.m_cursorX = nbt.getInt( "term_cursorX" );
-        this.m_cursorY = nbt.getInt( "term_cursorY" );
-        this.m_cursorBlink = nbt.getBoolean( "term_cursorBlink" );
-        this.m_cursorColour = nbt.getInt( "term_textColour" );
-        this.m_cursorBackgroundColour = nbt.getInt( "term_bgColour" );
+        cursorX = nbt.getInt( "term_cursorX" );
+        cursorY = nbt.getInt( "term_cursorY" );
+        cursorBlink = nbt.getBoolean( "term_cursorBlink" );
+        cursorColour = nbt.getInt( "term_textColour" );
+        cursorBackgroundColour = nbt.getInt( "term_bgColour" );
 
-        for( int n = 0; n < this.m_height; n++ )
+        for( int n = 0; n < height; n++ )
         {
-            this.m_text[n].fill( ' ' );
+            text[n].fill( ' ' );
             if( nbt.contains( "term_text_" + n ) )
             {
-                this.m_text[n].write( nbt.getString( "term_text_" + n ) );
+                text[n].write( nbt.getString( "term_text_" + n ) );
             }
-            this.m_textColour[n].fill( base16.charAt( this.m_cursorColour ) );
+            textColour[n].fill( base16.charAt( cursorColour ) );
             if( nbt.contains( "term_textColour_" + n ) )
             {
-                this.m_textColour[n].write( nbt.getString( "term_textColour_" + n ) );
+                textColour[n].write( nbt.getString( "term_textColour_" + n ) );
             }
-            this.m_backgroundColour[n].fill( base16.charAt( this.m_cursorBackgroundColour ) );
+            backgroundColour[n].fill( base16.charAt( cursorBackgroundColour ) );
             if( nbt.contains( "term_textBgColour_" + n ) )
             {
-                this.m_backgroundColour[n].write( nbt.getString( "term_textBgColour_" + n ) );
+                backgroundColour[n].write( nbt.getString( "term_textBgColour_" + n ) );
             }
         }
 
-        this.m_palette.readFromNBT( nbt );
-        this.setChanged();
+        palette.readFromNBT( nbt );
+        setChanged();
+    }
+
+    public static int getColour( char c, Colour def )
+    {
+        if( c >= '0' && c <= '9' ) return c - '0';
+        if( c >= 'a' && c <= 'f' ) return c - 'a' + 10;
+        return 15 - def.ordinal();
     }
 }

src/main/java/dan200/computercraft/core/terminal/TextBuffer.java

@@ -83,4 +83,4 @@ public class TextBuffer
     {
         return new String( text );
     }
-}
+}

src/main/java/dan200/computercraft/core/tracking/ComputerTracker.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.tracking;
 
 import dan200.computercraft.core.computer.Computer;
@@ -16,126 +15,108 @@ public class ComputerTracker
 {
     private final WeakReference<Computer> computer;
     private final int computerId;
-    private final Object2LongOpenHashMap<TrackingField> fields;
+
     private long tasks;
     private long totalTime;
     private long maxTime;
+
     private long serverCount;
     private long serverTime;
 
+    private final Object2LongOpenHashMap<TrackingField> fields;
+
     public ComputerTracker( Computer computer )
     {
         this.computer = new WeakReference<>( computer );
-        this.computerId = computer.getID();
-        this.fields = new Object2LongOpenHashMap<>();
+        computerId = computer.getID();
+        fields = new Object2LongOpenHashMap<>();
     }
 
     ComputerTracker( ComputerTracker timings )
     {
-        this.computer = timings.computer;
-        this.computerId = timings.computerId;
+        computer = timings.computer;
+        computerId = timings.computerId;
 
-        this.tasks = timings.tasks;
-        this.totalTime = timings.totalTime;
-        this.maxTime = timings.maxTime;
+        tasks = timings.tasks;
+        totalTime = timings.totalTime;
+        maxTime = timings.maxTime;
 
-        this.serverCount = timings.serverCount;
-        this.serverTime = timings.serverTime;
+        serverCount = timings.serverCount;
+        serverTime = timings.serverTime;
 
-        this.fields = new Object2LongOpenHashMap<>( timings.fields );
+        fields = new Object2LongOpenHashMap<>( timings.fields );
     }
 
     @Nullable
     public Computer getComputer()
     {
-        return this.computer.get();
+        return computer.get();
     }
 
     public int getComputerId()
     {
-        return this.computerId;
+        return computerId;
     }
 
     public long getTasks()
     {
-        return this.tasks;
+        return tasks;
     }
 
     public long getTotalTime()
     {
-        return this.totalTime;
+        return totalTime;
     }
 
     public long getMaxTime()
     {
-        return this.maxTime;
+        return maxTime;
     }
 
     public long getAverage()
     {
-        return this.totalTime / this.tasks;
+        return totalTime / tasks;
     }
 
     void addTaskTiming( long time )
     {
-        this.tasks++;
-        this.totalTime += time;
-        if( time > this.maxTime )
-        {
-            this.maxTime = time;
-        }
+        tasks++;
+        totalTime += time;
+        if( time > maxTime ) maxTime = time;
     }
 
     void addMainTiming( long time )
     {
-        this.serverCount++;
-        this.serverTime += time;
+        serverCount++;
+        serverTime += time;
     }
 
     void addValue( TrackingField field, long change )
     {
-        synchronized( this.fields )
+        synchronized( fields )
         {
-            this.fields.addTo( field, change );
+            fields.addTo( field, change );
+        }
+    }
+
+    public long get( TrackingField field )
+    {
+        if( field == TrackingField.TASKS ) return tasks;
+        if( field == TrackingField.MAX_TIME ) return maxTime;
+        if( field == TrackingField.TOTAL_TIME ) return totalTime;
+        if( field == TrackingField.AVERAGE_TIME ) return tasks == 0 ? 0 : totalTime / tasks;
+
+        if( field == TrackingField.SERVER_COUNT ) return serverCount;
+        if( field == TrackingField.SERVER_TIME ) return serverTime;
+
+        synchronized( fields )
+        {
+            return fields.getLong( field );
         }
     }
 
     public String getFormatted( TrackingField field )
     {
-        return field.format( this.get( field ) );
-    }
-
-    public long get( TrackingField field )
-    {
-        if( field == TrackingField.TASKS )
-        {
-            return this.tasks;
-        }
-        if( field == TrackingField.MAX_TIME )
-        {
-            return this.maxTime;
-        }
-        if( field == TrackingField.TOTAL_TIME )
-        {
-            return this.totalTime;
-        }
-        if( field == TrackingField.AVERAGE_TIME )
-        {
-            return this.tasks == 0 ? 0 : this.totalTime / this.tasks;
-        }
-
-        if( field == TrackingField.SERVER_COUNT )
-        {
-            return this.serverCount;
-        }
-        if( field == TrackingField.SERVER_TIME )
-        {
-            return this.serverTime;
-        }
-
-        synchronized( this.fields )
-        {
-            return this.fields.getLong( field );
-        }
+        return field.format( get( field ) );
     }
 }

src/main/java/dan200/computercraft/core/tracking/Tracker.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.tracking;
 
 import dan200.computercraft.core.computer.Computer;
@@ -35,8 +34,8 @@ public interface Tracker
     }
 
     /**
-     * Increment an arbitrary field by some value. Implementations may track how often this is called as well as the change, to compute some level of
-     * "average".
+     * Increment an arbitrary field by some value. Implementations may track how often this is called
+     * as well as the change, to compute some level of "average".
      *
      * @param computer The computer to increment
      * @param field    The field to increment.

src/main/java/dan200/computercraft/core/tracking/Tracking.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.tracking;
 
 import dan200.computercraft.core.computer.Computer;
@@ -29,10 +28,7 @@ public final class Tracking
         synchronized( lock )
         {
             TrackingContext context = contexts.get( uuid );
-            if( context == null )
-            {
-                contexts.put( uuid, context = new TrackingContext() );
-            }
+            if( context == null ) contexts.put( uuid, context = new TrackingContext() );
             return context;
         }
     }
@@ -48,61 +44,34 @@ public final class Tracking
 
     public static void addTaskTiming( Computer computer, long time )
     {
-        if( tracking.get() == 0 )
-        {
-            return;
-        }
+        if( tracking.get() == 0 ) return;
 
         synchronized( contexts )
         {
-            for( TrackingContext context : contexts.values() )
-            {
-                context.addTaskTiming( computer, time );
-            }
-            for( Tracker tracker : trackers )
-            {
-                tracker.addTaskTiming( computer, time );
-            }
+            for( TrackingContext context : contexts.values() ) context.addTaskTiming( computer, time );
+            for( Tracker tracker : trackers ) tracker.addTaskTiming( computer, time );
         }
     }
 
     public static void addServerTiming( Computer computer, long time )
     {
-        if( tracking.get() == 0 )
-        {
-            return;
-        }
+        if( tracking.get() == 0 ) return;
 
         synchronized( contexts )
         {
-            for( TrackingContext context : contexts.values() )
-            {
-                context.addServerTiming( computer, time );
-            }
-            for( Tracker tracker : trackers )
-            {
-                tracker.addServerTiming( computer, time );
-            }
+            for( TrackingContext context : contexts.values() ) context.addServerTiming( computer, time );
+            for( Tracker tracker : trackers ) tracker.addServerTiming( computer, time );
         }
     }
 
     public static void addValue( Computer computer, TrackingField field, long change )
     {
-        if( tracking.get() == 0 )
-        {
-            return;
-        }
+        if( tracking.get() == 0 ) return;
 
         synchronized( lock )
         {
-            for( TrackingContext context : contexts.values() )
-            {
-                context.addValue( computer, field, change );
-            }
-            for( Tracker tracker : trackers )
-            {
-                tracker.addValue( computer, field, change );
-            }
+            for( TrackingContext context : contexts.values() ) context.addValue( computer, field, change );
+            for( Tracker tracker : trackers ) tracker.addValue( computer, field, change );
         }
     }
 

src/main/java/dan200/computercraft/core/tracking/TrackingContext.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.tracking;
 
 import com.google.common.collect.MapMaker;
@@ -14,73 +13,63 @@ import java.util.List;
 import java.util.Map;
 
 /**
- * Tracks timing information about computers, including how long they ran for and the number of events they handled.
+ * Tracks timing information about computers, including how long they ran for
+ * and the number of events they handled.
  *
- * Note that this <em>will</em> track computers which have been deleted (hence the presence of {@link #timingLookup} and {@link #timings}
+ * Note that this <em>will</em> track computers which have been deleted (hence
+ * the presence of {@link #timingLookup} and {@link #timings}
  */
 public class TrackingContext implements Tracker
 {
-    private final List<ComputerTracker> timings = new ArrayList<>();
-    private final Map<Computer, ComputerTracker> timingLookup = new MapMaker().weakKeys()
-        .makeMap();
     private boolean tracking = false;
 
+    private final List<ComputerTracker> timings = new ArrayList<>();
+    private final Map<Computer, ComputerTracker> timingLookup = new MapMaker().weakKeys().makeMap();
+
     public synchronized void start()
     {
-        if( !this.tracking )
-        {
-            Tracking.tracking.incrementAndGet();
-        }
-        this.tracking = true;
+        if( !tracking ) Tracking.tracking.incrementAndGet();
+        tracking = true;
 
-        this.timings.clear();
-        this.timingLookup.clear();
+        timings.clear();
+        timingLookup.clear();
     }
 
     public synchronized boolean stop()
     {
-        if( !this.tracking )
-        {
-            return false;
-        }
+        if( !tracking ) return false;
 
         Tracking.tracking.decrementAndGet();
-        this.tracking = false;
-        this.timingLookup.clear();
+        tracking = false;
+        timingLookup.clear();
         return true;
     }
 
     public synchronized List<ComputerTracker> getImmutableTimings()
     {
         ArrayList<ComputerTracker> timings = new ArrayList<>( this.timings.size() );
-        for( ComputerTracker timing : this.timings )
-        {
-            timings.add( new ComputerTracker( timing ) );
-        }
+        for( ComputerTracker timing : this.timings ) timings.add( new ComputerTracker( timing ) );
         return timings;
     }
 
     public synchronized List<ComputerTracker> getTimings()
     {
-        return new ArrayList<>( this.timings );
+        return new ArrayList<>( timings );
     }
 
     @Override
     public void addTaskTiming( Computer computer, long time )
     {
-        if( !this.tracking )
-        {
-            return;
-        }
+        if( !tracking ) return;
 
         synchronized( this )
         {
-            ComputerTracker computerTimings = this.timingLookup.get( computer );
+            ComputerTracker computerTimings = timingLookup.get( computer );
             if( computerTimings == null )
             {
                 computerTimings = new ComputerTracker( computer );
-                this.timingLookup.put( computer, computerTimings );
-                this.timings.add( computerTimings );
+                timingLookup.put( computer, computerTimings );
+                timings.add( computerTimings );
             }
 
             computerTimings.addTaskTiming( time );
@@ -90,19 +79,16 @@ public class TrackingContext implements Tracker
     @Override
     public void addServerTiming( Computer computer, long time )
     {
-        if( !this.tracking )
-        {
-            return;
-        }
+        if( !tracking ) return;
 
         synchronized( this )
         {
-            ComputerTracker computerTimings = this.timingLookup.get( computer );
+            ComputerTracker computerTimings = timingLookup.get( computer );
             if( computerTimings == null )
             {
                 computerTimings = new ComputerTracker( computer );
-                this.timingLookup.put( computer, computerTimings );
-                this.timings.add( computerTimings );
+                timingLookup.put( computer, computerTimings );
+                timings.add( computerTimings );
             }
 
             computerTimings.addMainTiming( time );
@@ -112,19 +98,16 @@ public class TrackingContext implements Tracker
     @Override
     public void addValue( Computer computer, TrackingField field, long change )
     {
-        if( !this.tracking )
-        {
-            return;
-        }
+        if( !tracking ) return;
 
         synchronized( this )
         {
-            ComputerTracker computerTimings = this.timingLookup.get( computer );
+            ComputerTracker computerTimings = timingLookup.get( computer );
             if( computerTimings == null )
             {
                 computerTimings = new ComputerTracker( computer );
-                this.timingLookup.put( computer, computerTimings );
-                this.timings.add( computerTimings );
+                timingLookup.put( computer, computerTimings );
+                timings.add( computerTimings );
             }
 
             computerTimings.addValue( field, change );

src/main/java/dan200/computercraft/core/tracking/TrackingField.java

@@ -3,7 +3,6 @@
  * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.core.tracking;
 
 import java.util.Collections;
@@ -28,28 +27,41 @@ public final class TrackingField
     public static final TrackingField TURTLE_OPS = TrackingField.of( "turtle", TrackingField::formatDefault );
 
     public static final TrackingField HTTP_REQUESTS = TrackingField.of( "http", TrackingField::formatDefault );
-    public static final TrackingField COROUTINES_CREATED = TrackingField.of( "coroutines_created", x -> String.format( "%4d", x ) );
-    public static final TrackingField COROUTINES_DISPOSED = TrackingField.of( "coroutines_dead", x -> String.format( "%4d", x ) );
-    /**
-     * So technically a kibibyte, but let's not argue here.
-     */
-    private static final int KILOBYTE_SIZE = 1024;
-    private static final String SI_PREFIXES = "KMGT";
     public static final TrackingField HTTP_UPLOAD = TrackingField.of( "http_upload", TrackingField::formatBytes );
     public static final TrackingField HTTP_DOWNLOAD = TrackingField.of( "http_download", TrackingField::formatBytes );
+
     public static final TrackingField WEBSOCKET_INCOMING = TrackingField.of( "websocket_incoming", TrackingField::formatBytes );
     public static final TrackingField WEBSOCKET_OUTGOING = TrackingField.of( "websocket_outgoing", TrackingField::formatBytes );
+
+    public static final TrackingField COROUTINES_CREATED = TrackingField.of( "coroutines_created", x -> String.format( "%4d", x ) );
+    public static final TrackingField COROUTINES_DISPOSED = TrackingField.of( "coroutines_dead", x -> String.format( "%4d", x ) );
+
     private final String id;
     private final String translationKey;
     private final LongFunction<String> format;
 
+    public String id()
+    {
+        return id;
+    }
+
+    public String translationKey()
+    {
+        return translationKey;
+    }
+
     private TrackingField( String id, LongFunction<String> format )
     {
         this.id = id;
-        this.translationKey = "tracking_field.computercraft." + id + ".name";
+        translationKey = "tracking_field.computercraft." + id + ".name";
         this.format = format;
     }
 
+    public String format( long value )
+    {
+        return format.apply( value );
+    }
+
     public static TrackingField of( String id, LongFunction<String> format )
     {
         TrackingField field = new TrackingField( id, format );
@@ -67,32 +79,18 @@ public final class TrackingField
         return String.format( "%6d", value );
     }
 
+    /**
+     * So technically a kibibyte, but let's not argue here.
+     */
+    private static final int KILOBYTE_SIZE = 1024;
+
+    private static final String SI_PREFIXES = "KMGT";
+
     private static String formatBytes( long bytes )
     {
-        if( bytes < 1024 )
-        {
-            return String.format( "%10d B", bytes );
-        }
+        if( bytes < 1024 ) return String.format( "%10d B", bytes );
         int exp = (int) (Math.log( bytes ) / Math.log( KILOBYTE_SIZE ));
-        if( exp > SI_PREFIXES.length() )
-        {
-            exp = SI_PREFIXES.length();
-        }
+        if( exp > SI_PREFIXES.length() ) exp = SI_PREFIXES.length();
         return String.format( "%10.1f %siB", bytes / Math.pow( KILOBYTE_SIZE, exp ), SI_PREFIXES.charAt( exp - 1 ) );
     }
-
-    public String id()
-    {
-        return this.id;
-    }
-
-    public String translationKey()
-    {
-        return this.translationKey;
-    }
-
-    public String format( long value )
-    {
-        return this.format.apply( value );
-    }
 }

src/main/java/dan200/computercraft/shared/util/Config.java

@@ -5,10 +5,7 @@
  */
 package dan200.computercraft.shared.util;
 
-import com.electronwill.nightconfig.core.CommentedConfig;
-import com.electronwill.nightconfig.core.ConfigSpec;
-import com.electronwill.nightconfig.core.EnumGetMethod;
-import com.electronwill.nightconfig.core.UnmodifiableConfig;
+import com.electronwill.nightconfig.core.*;
 import com.electronwill.nightconfig.core.file.CommentedFileConfig;
 import com.electronwill.nightconfig.core.file.FileNotFoundAction;
 import com.google.common.base.CaseFormat;
@@ -30,8 +27,7 @@ import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
-public class Config
-{
+public class Config {
     private static final int MODEM_MAX_RANGE = 100000;
 
     public static final String TRANSLATION_PREFIX = "gui.computercraft.config.";
@@ -42,346 +38,327 @@ public class Config
     public static CommentedConfig serverConfig;
     public static CommentedConfig clientConfig;
 
-    private static final WorldSavePath serverDir = WorldSavePathAccess.createWorldSavePath( "serverconfig" );
+    private static final WorldSavePath serverDir = WorldSavePathAccess.createWorldSavePath("serverconfig");
     private static final String serverFileName = "computercraft-server.toml";
-    private static final Path clientPath = FabricLoader.INSTANCE.getConfigDir().resolve( "computercraft-client.toml" );
+    private static final Path clientPath = FabricLoader.INSTANCE.getConfigDir().resolve("computercraft-client.toml");
 
-    private Config()
-    {
+    private Config() {
     }
 
-    static
-    {
-        System.setProperty( "nightconfig.preserveInsertionOrder", "true" );
+    static {
+        System.setProperty("nightconfig.preserveInsertionOrder", "true");
 
         serverSpec = new CommentedConfigSpec();
         { // General computers
-            serverSpec.comment( "computer_space_limit",
-                "The disk space limit for computers and turtles, in bytes" );
-            serverSpec.define( "computer_space_limit", ComputerCraft.computerSpaceLimit );
+            serverSpec.comment("computer_space_limit",
+                    "The disk space limit for computers and turtles, in bytes");
+            serverSpec.define("computer_space_limit", ComputerCraft.computerSpaceLimit);
 
-            serverSpec.comment( "floppy_space_limit",
-                "The disk space limit for floppy disks, in bytes" );
-            serverSpec.define( "floppy_space_limit", ComputerCraft.floppySpaceLimit );
+            serverSpec.comment("floppy_space_limit",
+                    "The disk space limit for floppy disks, in bytes");
+            serverSpec.define("floppy_space_limit", ComputerCraft.floppySpaceLimit);
 
-            serverSpec.comment( "maximum_open_files",
-                "Set how many files a computer can have open at the same time. Set to 0 for unlimited." );
-            serverSpec.defineInRange( "maximum_open_files", ComputerCraft.maximumFilesOpen, 0, Integer.MAX_VALUE );
+            serverSpec.comment("maximum_open_files",
+                    "Set how many files a computer can have open at the same time. Set to 0 for unlimited.");
+            serverSpec.defineInRange("maximum_open_files", ComputerCraft.maximumFilesOpen, 0, Integer.MAX_VALUE);
 
-            serverSpec.comment( "disable_lua51_features",
-                "Set this to true to disable Lua 5.1 functions that will be removed in a future update. " +
-                    "Useful for ensuring forward compatibility of your programs now." );
-            serverSpec.define( "disable_lua51_features", ComputerCraft.disableLua51Features );
+            serverSpec.comment("disable_lua51_features",
+                    "Set this to true to disable Lua 5.1 functions that will be removed in a future update. " +
+                    "Useful for ensuring forward compatibility of your programs now.");
+            serverSpec.define("disable_lua51_features", ComputerCraft.disableLua51Features);
 
-            serverSpec.comment( "default_computer_settings",
-                "A comma separated list of default system settings to set on new computers. Example: " +
+            serverSpec.comment("default_computer_settings",
+                    "A comma separated list of default system settings to set on new computers. Example: " +
                     "\"shell.autocomplete=false,lua.autocomplete=false,edit.autocomplete=false\" will disable all " +
-                    "autocompletion" );
-            serverSpec.define( "default_computer_settings", ComputerCraft.defaultComputerSettings );
+                    "autocompletion");
+            serverSpec.define("default_computer_settings", ComputerCraft.defaultComputerSettings);
 
-            serverSpec.comment( "debug_enabled",
-                "Enable Lua's debug library. This is sandboxed to each computer, so is generally safe to be used by players." );
-            serverSpec.define( "debug_enabled", ComputerCraft.debugEnable );
+            serverSpec.comment("debug_enabled",
+                    "Enable Lua's debug library. This is sandboxed to each computer, so is generally safe to be used by players.");
+            serverSpec.define("debug_enabled", ComputerCraft.debugEnable);
 
-            serverSpec.comment( "log_computer_errors",
-                "Log exceptions thrown by peripherals and other Lua objects.\n" +
-                    "This makes it easier for mod authors to debug problems, but may result in log spam should people use buggy methods." );
-            serverSpec.define( "log_computer_errors", ComputerCraft.logComputerErrors );
+            serverSpec.comment("log_computer_errors",
+                    "Log exceptions thrown by peripherals and other Lua objects.\n" +
+                    "This makes it easier for mod authors to debug problems, but may result in log spam should people use buggy methods.");
+            serverSpec.define("log_computer_errors", ComputerCraft.logComputerErrors);
 
-            serverSpec.comment( "command_require_creative",
-                "Require players to be in creative mode and be opped in order to interact with command computers." +
-                    "This is the default behaviour for vanilla's Command blocks." );
-            serverSpec.define( "command_require_creative", ComputerCraft.commandRequireCreative );
+            serverSpec.comment("command_require_creative",
+                    "Require players to be in creative mode and be opped in order to interact with command computers." +
+                    "This is the default behaviour for vanilla's Command blocks.");
+            serverSpec.define("command_require_creative", ComputerCraft.commandRequireCreative);
         }
 
         { // Execution
-            serverSpec.comment( "execution",
-                "Controls execution behaviour of computers. This is largely intended for fine-tuning " +
-                    "servers, and generally shouldn't need to be touched" );
+            serverSpec.comment("execution",
+                    "Controls execution behaviour of computers. This is largely intended for fine-tuning " +
+                    "servers, and generally shouldn't need to be touched");
 
-            serverSpec.comment( "execution.computer_threads",
-                "Set the number of threads computers can run on. A higher number means more computers can run " +
+            serverSpec.comment("execution.computer_threads",
+                    "Set the number of threads computers can run on. A higher number means more computers can run " +
                     "at once, but may induce lag.\n" +
-                    "Please note that some mods may not work with a thread count higher than 1. Use with caution." );
-            serverSpec.defineInRange( "execution.computer_threads", ComputerCraft.computerThreads, 1, Integer.MAX_VALUE );
+                    "Please note that some mods may not work with a thread count higher than 1. Use with caution.");
+            serverSpec.defineInRange("execution.computer_threads", ComputerCraft.computerThreads, 1, Integer.MAX_VALUE);
 
-            serverSpec.comment( "execution.max_main_global_time",
-                "The maximum time that can be spent executing tasks in a single tick, in milliseconds.\n" +
+            serverSpec.comment("execution.max_main_global_time",
+                    "The maximum time that can be spent executing tasks in a single tick, in milliseconds.\n" +
                     "Note, we will quite possibly go over this limit, as there's no way to tell how long a will take " +
-                    "- this aims to be the upper bound of the average time." );
-            serverSpec.defineInRange( "execution.max_main_global_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainGlobalTime ), 1, Integer.MAX_VALUE );
+                    "- this aims to be the upper bound of the average time.");
+            serverSpec.defineInRange("execution.max_main_global_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainGlobalTime ), 1, Integer.MAX_VALUE);
 
-            serverSpec.comment( "execution.max_main_computer_time",
-                "The ideal maximum time a computer can execute for in a tick, in milliseconds.\n" +
+            serverSpec.comment("execution.max_main_computer_time",
+                    "The ideal maximum time a computer can execute for in a tick, in milliseconds.\n" +
                     "Note, we will quite possibly go over this limit, as there's no way to tell how long a will take " +
-                    "- this aims to be the upper bound of the average time." );
-            serverSpec.defineInRange( "execution.max_main_computer_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainComputerTime ), 1, Integer.MAX_VALUE );
+                    "- this aims to be the upper bound of the average time.");
+            serverSpec.defineInRange("execution.max_main_computer_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainComputerTime ), 1, Integer.MAX_VALUE);
         }
 
         { // HTTP
-            serverSpec.comment( "http", "Controls the HTTP API" );
+            serverSpec.comment("http", "Controls the HTTP API");
 
-            serverSpec.comment( "http.enabled",
-                "Enable the \"http\" API on Computers (see \"rules\" for more fine grained control than this)." );
-            serverSpec.define( "http.enabled", ComputerCraft.httpEnabled );
+            serverSpec.comment("http.enabled",
+                    "Enable the \"http\" API on Computers (see \"rules\" for more fine grained control than this).");
+            serverSpec.define("http.enabled", ComputerCraft.httpEnabled);
 
-            serverSpec.comment( "http.websocket_enabled",
-                "Enable use of http websockets. This requires the \"http_enable\" option to also be true." );
-            serverSpec.define( "http.websocket_enabled", ComputerCraft.httpWebsocketEnabled );
+            serverSpec.comment("http.websocket_enabled",
+                    "Enable use of http websockets. This requires the \"http_enable\" option to also be true.");
+            serverSpec.define("http.websocket_enabled", ComputerCraft.httpWebsocketEnabled);
 
-            serverSpec.comment( "http.rules",
-                "A list of rules which control behaviour of the \"http\" API for specific domains or IPs.\n" +
+            serverSpec.comment("http.rules",
+                    "A list of rules which control behaviour of the \"http\" API for specific domains or IPs.\n" +
                     "Each rule is an item with a 'host' to match against, and a series of properties. " +
                     "The host may be a domain name (\"pastebin.com\"),\n" +
-                    "wildcard (\"*.pastebin.com\") or CIDR notation (\"127.0.0.0/8\"). If no rules, the domain is blocked." );
-            serverSpec.defineList( "http.rules", Arrays.asList(
-                AddressRuleConfig.makeRule( "$private", Action.DENY ),
-                AddressRuleConfig.makeRule( "*", Action.ALLOW )
-            ), x -> x instanceof UnmodifiableConfig && AddressRuleConfig.checkRule( (UnmodifiableConfig) x ) );
+                    "wildcard (\"*.pastebin.com\") or CIDR notation (\"127.0.0.0/8\"). If no rules, the domain is blocked.");
+            serverSpec.defineList("http.rules", Arrays.asList(
+                            AddressRuleConfig.makeRule("$private", Action.DENY),
+                            AddressRuleConfig.makeRule("*", Action.ALLOW)
+                    ), x -> x instanceof UnmodifiableConfig && AddressRuleConfig.checkRule((UnmodifiableConfig) x));
 
-            serverSpec.comment( "http.max_requests",
-                "The number of http requests a computer can make at one time. Additional requests will be queued, and sent when the running requests have finished. Set to 0 for unlimited." );
-            serverSpec.defineInRange( "http.max_requests", ComputerCraft.httpMaxRequests, 0, Integer.MAX_VALUE );
+            serverSpec.comment("http.max_requests",
+                    "The number of http requests a computer can make at one time. Additional requests will be queued, and sent when the running requests have finished. Set to 0 for unlimited.");
+            serverSpec.defineInRange("http.max_requests", ComputerCraft.httpMaxRequests, 0, Integer.MAX_VALUE);
 
-            serverSpec.comment( "http.max_websockets",
-                "The number of websockets a computer can have open at one time. Set to 0 for unlimited." );
-            serverSpec.defineInRange( "http.max_websockets", ComputerCraft.httpMaxWebsockets, 1, Integer.MAX_VALUE );
+            serverSpec.comment("http.max_websockets",
+                    "The number of websockets a computer can have open at one time. Set to 0 for unlimited.");
+            serverSpec.defineInRange("http.max_websockets", ComputerCraft.httpMaxWebsockets, 1, Integer.MAX_VALUE);
         }
 
         { // Peripherals
-            serverSpec.comment( "peripheral", "Various options relating to peripherals." );
+            serverSpec.comment("peripheral", "Various options relating to peripherals.");
 
-            serverSpec.comment( "peripheral.command_block_enabled",
-                "Enable Command Block peripheral support" );
-            serverSpec.define( "peripheral.command_block_enabled", ComputerCraft.enableCommandBlock );
+            serverSpec.comment("peripheral.command_block_enabled",
+                    "Enable Command Block peripheral support");
+            serverSpec.define("peripheral.command_block_enabled", ComputerCraft.enableCommandBlock);
 
-            serverSpec.comment( "peripheral.modem_range",
-                "The range of Wireless Modems at low altitude in clear weather, in meters" );
-            serverSpec.defineInRange( "peripheral.modem_range", ComputerCraft.modemRange, 0, MODEM_MAX_RANGE );
+            serverSpec.comment("peripheral.modem_range",
+                    "The range of Wireless Modems at low altitude in clear weather, in meters");
+            serverSpec.defineInRange("peripheral.modem_range", ComputerCraft.modemRange, 0, MODEM_MAX_RANGE);
 
-            serverSpec.comment( "peripheral.modem_high_altitude_range",
-                "The range of Wireless Modems at maximum altitude in clear weather, in meters" );
-            serverSpec.defineInRange( "peripheral.modem_high_altitude_range", ComputerCraft.modemHighAltitudeRange, 0, MODEM_MAX_RANGE );
+            serverSpec.comment("peripheral.modem_high_altitude_range",
+                    "The range of Wireless Modems at maximum altitude in clear weather, in meters");
+            serverSpec.defineInRange("peripheral.modem_high_altitude_range", ComputerCraft.modemHighAltitudeRange, 0, MODEM_MAX_RANGE);
 
-            serverSpec.comment( "peripheral.modem_range_during_storm",
-                "The range of Wireless Modems at low altitude in stormy weather, in meters" );
-            serverSpec.defineInRange( "peripheral.modem_range_during_storm", ComputerCraft.modemRangeDuringStorm, 0, MODEM_MAX_RANGE );
+            serverSpec.comment("peripheral.modem_range_during_storm",
+                    "The range of Wireless Modems at low altitude in stormy weather, in meters");
+            serverSpec.defineInRange("peripheral.modem_range_during_storm", ComputerCraft.modemRangeDuringStorm, 0, MODEM_MAX_RANGE);
 
-            serverSpec.comment( "peripheral.modem_high_altitude_range_during_storm",
-                "The range of Wireless Modems at maximum altitude in stormy weather, in meters" );
-            serverSpec.defineInRange( "peripheral.modem_high_altitude_range_during_storm", ComputerCraft.modemHighAltitudeRangeDuringStorm, 0, MODEM_MAX_RANGE );
+            serverSpec.comment("peripheral.modem_high_altitude_range_during_storm",
+                    "The range of Wireless Modems at maximum altitude in stormy weather, in meters");
+            serverSpec.defineInRange("peripheral.modem_high_altitude_range_during_storm", ComputerCraft.modemHighAltitudeRangeDuringStorm, 0, MODEM_MAX_RANGE);
 
-            serverSpec.comment( "peripheral.max_notes_per_tick",
-                "Maximum amount of notes a speaker can play at once" );
-            serverSpec.defineInRange( "peripheral.max_notes_per_tick", ComputerCraft.maxNotesPerTick, 1, Integer.MAX_VALUE );
+            serverSpec.comment("peripheral.max_notes_per_tick",
+                    "Maximum amount of notes a speaker can play at once");
+            serverSpec.defineInRange("peripheral.max_notes_per_tick", ComputerCraft.maxNotesPerTick, 1, Integer.MAX_VALUE);
 
-            serverSpec.comment( "peripheral.monitor_bandwidth",
-                "The limit to how much monitor data can be sent *per tick*. Note:\n" +
+            serverSpec.comment("peripheral.monitor_bandwidth",
+                    "The limit to how much monitor data can be sent *per tick*. Note:\n" +
                     " - Bandwidth is measured before compression, so the data sent to the client is smaller.\n" +
                     " - This ignores the number of players a packet is sent to. Updating a monitor for one player consumes " +
                     "the same bandwidth limit as sending to 20.\n" +
                     " - A full sized monitor sends ~25kb of data. So the default (1MB) allows for ~40 monitors to be updated " +
                     "in a single tick. \n" +
-                    "Set to 0 to disable." );
-            serverSpec.defineInRange( "peripheral.monitor_bandwidth", (int) ComputerCraft.monitorBandwidth, 0, Integer.MAX_VALUE );
+                    "Set to 0 to disable.");
+            serverSpec.defineInRange("peripheral.monitor_bandwidth", (int) ComputerCraft.monitorBandwidth, 0, Integer.MAX_VALUE);
         }
 
         { // Turtles
-            serverSpec.comment( "turtle", "Various options relating to turtles." );
+            serverSpec.comment("turtle", "Various options relating to turtles.");
 
-            serverSpec.comment( "turtle.need_fuel",
-                "Set whether Turtles require fuel to move" );
-            serverSpec.define( "turtle.need_fuel", ComputerCraft.turtlesNeedFuel );
+            serverSpec.comment("turtle.need_fuel",
+                    "Set whether Turtles require fuel to move");
+            serverSpec.define("turtle.need_fuel", ComputerCraft.turtlesNeedFuel);
 
-            serverSpec.comment( "turtle.normal_fuel_limit", "The fuel limit for Turtles" );
-            serverSpec.defineInRange( "turtle.normal_fuel_limit", ComputerCraft.turtleFuelLimit, 0, Integer.MAX_VALUE );
+            serverSpec.comment("turtle.normal_fuel_limit", "The fuel limit for Turtles");
+            serverSpec.defineInRange("turtle.normal_fuel_limit", ComputerCraft.turtleFuelLimit, 0, Integer.MAX_VALUE);
 
-            serverSpec.comment( "turtle.advanced_fuel_limit",
-                "The fuel limit for Advanced Turtles" );
-            serverSpec.defineInRange( "turtle.advanced_fuel_limit", ComputerCraft.advancedTurtleFuelLimit, 0, Integer.MAX_VALUE );
+            serverSpec.comment("turtle.advanced_fuel_limit",
+                    "The fuel limit for Advanced Turtles");
+            serverSpec.defineInRange("turtle.advanced_fuel_limit", ComputerCraft.advancedTurtleFuelLimit, 0, Integer.MAX_VALUE);
 
-            serverSpec.comment( "turtle.obey_block_protection",
-                "If set to true, Turtles will be unable to build, dig, or enter protected areas (such as near the server spawn point)" );
-            serverSpec.define( "turtle.obey_block_protection", ComputerCraft.turtlesObeyBlockProtection );
+            serverSpec.comment("turtle.obey_block_protection",
+                    "If set to true, Turtles will be unable to build, dig, or enter protected areas (such as near the server spawn point)");
+            serverSpec.define("turtle.obey_block_protection", ComputerCraft.turtlesObeyBlockProtection);
 
-            serverSpec.comment( "turtle.can_push",
-                "If set to true, Turtles will push entities out of the way instead of stopping if there is space to do so" );
-            serverSpec.define( "turtle.can_push", ComputerCraft.turtlesCanPush );
+            serverSpec.comment("turtle.can_push",
+                    "If set to true, Turtles will push entities out of the way instead of stopping if there is space to do so");
+            serverSpec.define("turtle.can_push", ComputerCraft.turtlesCanPush);
 
-            serverSpec.comment( "turtle.disabled_actions",
-                "A list of turtle actions which are disabled." );
-            serverSpec.defineList( "turtle.disabled_actions", Collections.emptyList(), x -> x instanceof String && getAction( (String) x ) != null );
+            serverSpec.comment("turtle.disabled_actions",
+                    "A list of turtle actions which are disabled.");
+            serverSpec.defineList("turtle.disabled_actions", Collections.emptyList(), x -> x instanceof String && getAction((String) x) != null);
         }
 
         {
-            serverSpec.comment( "term_sizes", "Configure the size of various computer's terminals.\n" +
-                "Larger terminals require more bandwidth, so use with care." );
+            serverSpec.comment("term_sizes", "Configure the size of various computer's terminals.\n" +
+                    "Larger terminals require more bandwidth, so use with care.");
 
-            serverSpec.comment( "term_sizes.computer", "Terminal size of computers" );
-            serverSpec.defineInRange( "term_sizes.computer.width", ComputerCraft.computerTermWidth, 1, 255 );
-            serverSpec.defineInRange( "term_sizes.computer.height", ComputerCraft.computerTermHeight, 1, 255 );
+            serverSpec.comment("term_sizes.computer", "Terminal size of computers");
+            serverSpec.defineInRange("term_sizes.computer.width", ComputerCraft.computerTermWidth, 1, 255);
+            serverSpec.defineInRange("term_sizes.computer.height", ComputerCraft.computerTermHeight, 1, 255);
 
-            serverSpec.comment( "term_sizes.pocket_computer", "Terminal size of pocket computers" );
-            serverSpec.defineInRange( "term_sizes.pocket_computer.width", ComputerCraft.pocketTermWidth, 1, 255 );
-            serverSpec.defineInRange( "term_sizes.pocket_computer.height", ComputerCraft.pocketTermHeight, 1, 255 );
+            serverSpec.comment("term_sizes.pocket_computer", "Terminal size of pocket computers");
+            serverSpec.defineInRange("term_sizes.pocket_computer.width", ComputerCraft.pocketTermWidth, 1, 255);
+            serverSpec.defineInRange("term_sizes.pocket_computer.height", ComputerCraft.pocketTermHeight, 1, 255);
 
-            serverSpec.comment( "term_sizes.monitor", "Maximum size of monitors (in blocks)" );
-            serverSpec.defineInRange( "term_sizes.monitor.width", ComputerCraft.monitorWidth, 1, 32 );
-            serverSpec.defineInRange( "term_sizes.monitor.height", ComputerCraft.monitorHeight, 1, 32 );
+            serverSpec.comment("term_sizes.monitor", "Maximum size of monitors (in blocks)");
+            serverSpec.defineInRange("term_sizes.monitor.width", ComputerCraft.monitorWidth, 1, 32);
+            serverSpec.defineInRange("term_sizes.monitor.height", ComputerCraft.monitorHeight, 1, 32);
         }
 
         clientSpec = new CommentedConfigSpec();
 
-        clientSpec.comment( "monitor_renderer",
-            "The renderer to use for monitors. Generally this should be kept at \"best\" - if " +
-                "monitors have performance issues, you may wish to experiment with alternative renderers." );
-        clientSpec.defineRestrictedEnum( "monitor_renderer", MonitorRenderer.BEST, EnumSet.allOf( MonitorRenderer.class ), EnumGetMethod.NAME_IGNORECASE );
+        clientSpec.comment("monitor_renderer",
+                "The renderer to use for monitors. Generally this should be kept at \"best\" - if " +
+                "monitors have performance issues, you may wish to experiment with alternative renderers.");
+        clientSpec.defineRestrictedEnum("monitor_renderer", MonitorRenderer.BEST, EnumSet.allOf(MonitorRenderer.class), EnumGetMethod.NAME_IGNORECASE);
 
-        clientSpec.comment( "monitor_distance",
-            "The maximum distance monitors will render at. This defaults to the standard tile entity limit, " +
+        clientSpec.comment("monitor_distance",
+                "The maximum distance monitors will render at. This defaults to the standard tile entity limit, " +
                 "but may be extended if you wish to build larger monitors." );
-        clientSpec.defineInRange( "monitor_distance", 64, 16, 1024 );
+        clientSpec.defineInRange("monitor_distance", 64, 16, 1024);
     }
 
-    private static final FileNotFoundAction MAKE_DIRECTORIES = ( file, configFormat ) -> {
-        Files.createDirectories( file.getParent() );
-        Files.createFile( file );
-        configFormat.initEmptyFile( file );
+    private static final FileNotFoundAction MAKE_DIRECTORIES = (file, configFormat) -> {
+        Files.createDirectories(file.getParent());
+        Files.createFile(file);
+        configFormat.initEmptyFile(file);
         return false;
     };
 
-    private static CommentedFileConfig buildFileConfig( Path path )
-    {
-        return CommentedFileConfig.builder( path )
-            .onFileNotFound( MAKE_DIRECTORIES )
-            .preserveInsertionOrder()
-            .build();
+    private static CommentedFileConfig buildFileConfig(Path path) {
+        return CommentedFileConfig.builder(path)
+                .onFileNotFound(MAKE_DIRECTORIES)
+                .preserveInsertionOrder()
+                .build();
     }
 
-    public static void serverStarting( MinecraftServer server )
-    {
-        Path serverPath = server.getSavePath( serverDir ).resolve( serverFileName );
+    public static void serverStarting(MinecraftServer server) {
+        Path serverPath = server.getSavePath(serverDir).resolve(serverFileName);
 
-        try( CommentedFileConfig config = buildFileConfig( serverPath ) )
-        {
+        try(CommentedFileConfig config = buildFileConfig(serverPath)) {
             config.load();
-            serverSpec.correct( config, Config::correctionListener );
+            serverSpec.correct(config, Config::correctionListener);
             config.save();
             serverConfig = config;
             sync();
         }
     }
 
-    public static void serverStopping( MinecraftServer server )
-    {
+    public static void serverStopping(MinecraftServer server) {
         serverConfig = null;
     }
 
-    public static void clientStarted( MinecraftClient client )
-    {
-        try( CommentedFileConfig config = buildFileConfig( clientPath ) )
-        {
+    public static void clientStarted(MinecraftClient client) {
+        try (CommentedFileConfig config = buildFileConfig(clientPath)) {
             config.load();
-            clientSpec.correct( config, Config::correctionListener );
+            clientSpec.correct(config, Config::correctionListener);
             config.save();
             clientConfig = config;
             sync();
         }
     }
 
-    private static void correctionListener( ConfigSpec.CorrectionAction action, List<String> path, Object incorrectValue, Object correctedValue )
-    {
-        String key = String.join( ".", path );
-        switch( action )
-        {
+    private static void correctionListener(ConfigSpec.CorrectionAction action, List<String> path, Object incorrectValue, Object correctedValue) {
+        String key = String.join(".", path);
+        switch(action) {
             case ADD:
-                ComputerCraft.log.warn( "Config key {} missing -> added default value.", key );
-                break;
+                ComputerCraft.log.warn("Config key {} missing -> added default value.", key); break;
             case REMOVE:
-                ComputerCraft.log.warn( "Config key {} not defined -> removed from config.", key );
-                break;
+                ComputerCraft.log.warn("Config key {} not defined -> removed from config.", key); break;
             case REPLACE:
-                ComputerCraft.log.warn( "Config key {} not valid -> replaced with default value.", key );
+                ComputerCraft.log.warn("Config key {} not valid -> replaced with default value.", key);
         }
     }
 
-    public static void sync()
-    {
-        if( serverConfig != null )
-        {
+    public static void sync() {
+        if(serverConfig != null) {
             // General
-            ComputerCraft.computerSpaceLimit = serverConfig.<Integer>get( "computer_space_limit" );
-            ComputerCraft.floppySpaceLimit = serverConfig.<Integer>get( "floppy_space_limit" );
-            ComputerCraft.maximumFilesOpen = serverConfig.<Integer>get( "maximum_open_files" );
-            ComputerCraft.disableLua51Features = serverConfig.<Boolean>get( "disable_lua51_features" );
-            ComputerCraft.defaultComputerSettings = serverConfig.<String>get( "default_computer_settings" );
-            ComputerCraft.debugEnable = serverConfig.<Boolean>get( "debug_enabled" );
-            ComputerCraft.logComputerErrors = serverConfig.<Boolean>get( "log_computer_errors" );
-            ComputerCraft.commandRequireCreative = serverConfig.<Boolean>get( "command_require_creative" );
+            ComputerCraft.computerSpaceLimit = serverConfig.<Integer>get("computer_space_limit");
+            ComputerCraft.floppySpaceLimit = serverConfig.<Integer>get("floppy_space_limit");
+            ComputerCraft.maximumFilesOpen = serverConfig.<Integer>get("maximum_open_files");
+            ComputerCraft.disableLua51Features = serverConfig.<Boolean>get("disable_lua51_features");
+            ComputerCraft.defaultComputerSettings = serverConfig.<String>get("default_computer_settings");
+            ComputerCraft.debugEnable = serverConfig.<Boolean>get("debug_enabled");
+            ComputerCraft.logComputerErrors = serverConfig.<Boolean>get("log_computer_errors");
+            ComputerCraft.commandRequireCreative = serverConfig.<Boolean>get("command_require_creative");
 
             // Execution
-            ComputerCraft.computerThreads = serverConfig.<Integer>get( "execution.computer_threads" );
-            ComputerCraft.maxMainGlobalTime = TimeUnit.MILLISECONDS.toNanos( serverConfig.<Integer>get( "execution.max_main_global_time" ) );
-            ComputerCraft.maxMainComputerTime = TimeUnit.MILLISECONDS.toNanos( serverConfig.<Integer>get( "execution.max_main_computer_time" ) );
+            ComputerCraft.computerThreads = serverConfig.<Integer>get("execution.computer_threads");
+            ComputerCraft.maxMainGlobalTime = TimeUnit.MILLISECONDS.toNanos(serverConfig.<Integer>get("execution.max_main_global_time"));
+            ComputerCraft.maxMainComputerTime = TimeUnit.MILLISECONDS.toNanos(serverConfig.<Integer>get("execution.max_main_computer_time"));
 
             // HTTP
-            ComputerCraft.httpEnabled = serverConfig.<Boolean>get( "http.enabled" );
-            ComputerCraft.httpWebsocketEnabled = serverConfig.<Boolean>get( "http.websocket_enabled" );
-            ComputerCraft.httpRules = serverConfig.<List<UnmodifiableConfig>>get( "http.rules" ).stream().map( AddressRuleConfig::parseRule )
-                .filter( Objects::nonNull ).collect( Collectors.toList() );
-            ComputerCraft.httpMaxRequests = serverConfig.<Integer>get( "http.max_requests" );
-            ComputerCraft.httpMaxWebsockets = serverConfig.<Integer>get( "http.max_websockets" );
+            ComputerCraft.httpEnabled = serverConfig.<Boolean>get("http.enabled");
+            ComputerCraft.httpWebsocketEnabled = serverConfig.<Boolean>get("http.websocket_enabled");
+            ComputerCraft.httpRules = serverConfig.<List<UnmodifiableConfig>>get("http.rules").stream().map(AddressRuleConfig::parseRule)
+                    .filter(Objects::nonNull).collect(Collectors.toList());
+            ComputerCraft.httpMaxRequests = serverConfig.<Integer>get("http.max_requests");
+            ComputerCraft.httpMaxWebsockets = serverConfig.<Integer>get("http.max_websockets");
 
             // Peripherals
-            ComputerCraft.enableCommandBlock = serverConfig.<Boolean>get( "peripheral.command_block_enabled" );
-            ComputerCraft.modemRange = serverConfig.<Integer>get( "peripheral.modem_range" );
-            ComputerCraft.modemHighAltitudeRange = serverConfig.<Integer>get( "peripheral.modem_high_altitude_range" );
-            ComputerCraft.modemRangeDuringStorm = serverConfig.<Integer>get( "peripheral.modem_range_during_storm" );
-            ComputerCraft.modemHighAltitudeRangeDuringStorm = serverConfig.<Integer>get( "peripheral.modem_high_altitude_range_during_storm" );
-            ComputerCraft.maxNotesPerTick = serverConfig.<Integer>get( "peripheral.max_notes_per_tick" );
-            ComputerCraft.monitorBandwidth = serverConfig.<Integer>get( "peripheral.monitor_bandwidth" );
+            ComputerCraft.enableCommandBlock = serverConfig.<Boolean>get("peripheral.command_block_enabled");
+            ComputerCraft.modemRange = serverConfig.<Integer>get("peripheral.modem_range");
+            ComputerCraft.modemHighAltitudeRange = serverConfig.<Integer>get("peripheral.modem_high_altitude_range");
+            ComputerCraft.modemRangeDuringStorm = serverConfig.<Integer>get("peripheral.modem_range_during_storm");
+            ComputerCraft.modemHighAltitudeRangeDuringStorm = serverConfig.<Integer>get("peripheral.modem_high_altitude_range_during_storm");
+            ComputerCraft.maxNotesPerTick = serverConfig.<Integer>get("peripheral.max_notes_per_tick");
+            ComputerCraft.monitorBandwidth = serverConfig.<Integer>get("peripheral.monitor_bandwidth");
 
             // Turtles
-            ComputerCraft.turtlesNeedFuel = serverConfig.<Boolean>get( "turtle.need_fuel" );
-            ComputerCraft.turtleFuelLimit = serverConfig.<Integer>get( "turtle.normal_fuel_limit" );
-            ComputerCraft.advancedTurtleFuelLimit = serverConfig.<Integer>get( "turtle.advanced_fuel_limit" );
-            ComputerCraft.turtlesObeyBlockProtection = serverConfig.<Boolean>get( "turtle.obey_block_protection" );
-            ComputerCraft.turtlesCanPush = serverConfig.<Boolean>get( "turtle.can_push" );
+            ComputerCraft.turtlesNeedFuel = serverConfig.<Boolean>get("turtle.need_fuel");
+            ComputerCraft.turtleFuelLimit = serverConfig.<Integer>get("turtle.normal_fuel_limit");
+            ComputerCraft.advancedTurtleFuelLimit = serverConfig.<Integer>get("turtle.advanced_fuel_limit");
+            ComputerCraft.turtlesObeyBlockProtection = serverConfig.<Boolean>get("turtle.obey_block_protection");
+            ComputerCraft.turtlesCanPush = serverConfig.<Boolean>get("turtle.can_push");
 
             ComputerCraft.turtleDisabledActions.clear();
-            for( String value : serverConfig.<List<String>>get( "turtle.disabled_actions" ) )
-            {
-                ComputerCraft.turtleDisabledActions.add( getAction( value ) );
+            for(String value : serverConfig.<List<String>>get("turtle.disabled_actions")) {
+                ComputerCraft.turtleDisabledActions.add(getAction(value));
             }
 
             // Terminal Size
-            ComputerCraft.computerTermWidth = serverConfig.<Integer>get( "term_sizes.computer.width" );
-            ComputerCraft.computerTermHeight = serverConfig.<Integer>get( "term_sizes.computer.height" );
-            ComputerCraft.pocketTermWidth = serverConfig.<Integer>get( "term_sizes.pocket_computer.width" );
-            ComputerCraft.pocketTermHeight = serverConfig.<Integer>get( "term_sizes.pocket_computer.height" );
-            ComputerCraft.monitorWidth = serverConfig.<Integer>get( "term_sizes.monitor.width" );
-            ComputerCraft.monitorHeight = serverConfig.<Integer>get( "term_sizes.monitor.height" );
+            ComputerCraft.computerTermWidth = serverConfig.<Integer>get("term_sizes.computer.width");
+            ComputerCraft.computerTermHeight = serverConfig.<Integer>get("term_sizes.computer.height");
+            ComputerCraft.pocketTermWidth = serverConfig.<Integer>get("term_sizes.pocket_computer.width");
+            ComputerCraft.pocketTermHeight = serverConfig.<Integer>get("term_sizes.pocket_computer.height");
+            ComputerCraft.monitorWidth = serverConfig.<Integer>get("term_sizes.monitor.width");
+            ComputerCraft.monitorHeight = serverConfig.<Integer>get("term_sizes.monitor.height");
         }
 
         // Client
-        if( clientConfig != null )
-        {
-            ComputerCraft.monitorRenderer = clientConfig.getEnum( "monitor_renderer", MonitorRenderer.class );
-            int distance = clientConfig.get( "monitor_distance" );
+        if(clientConfig != null) {
+            ComputerCraft.monitorRenderer = clientConfig.getEnum("monitor_renderer", MonitorRenderer.class);
+            int distance = clientConfig.get("monitor_distance");
             ComputerCraft.monitorDistanceSq = distance * distance;
         }
     }
 
-    private static final Converter<String, String> converter = CaseFormat.LOWER_CAMEL.converterTo( CaseFormat.UPPER_UNDERSCORE );
+    private static final Converter<String, String> converter = CaseFormat.LOWER_CAMEL.converterTo(CaseFormat.UPPER_UNDERSCORE);
 
-    private static TurtleAction getAction( String value )
-    {
-        try
-        {
-            return TurtleAction.valueOf( converter.convert( value ) );
+    private static TurtleAction getAction(String value) {
+        try {
+            return TurtleAction.valueOf(converter.convert(value));
         }
-        catch( IllegalArgumentException e )
-        {
+        catch(IllegalArgumentException e) {
             return null;
         }
     }