Merge branch 'mc-1.18.x' into mc-1.19.x

src/main/java/dan200/computercraft/ComputerCraft.java

@@ -9,8 +9,6 @@ import dan200.computercraft.core.apis.http.options.Action;
 import dan200.computercraft.core.apis.http.options.AddressRule;
 import dan200.computercraft.shared.Config;
 import dan200.computercraft.shared.Registry;
-import dan200.computercraft.shared.computer.core.ClientComputerRegistry;
-import dan200.computercraft.shared.computer.core.ServerComputerRegistry;
 import dan200.computercraft.shared.peripheral.monitor.MonitorRenderer;
 import net.minecraftforge.fml.common.Mod;
 import org.slf4j.Logger;
@@ -76,11 +74,6 @@ public final class ComputerCraft
     public static int monitorWidth = 8;
     public static int monitorHeight = 6;
 
-    // Registries
-    public static final ClientComputerRegistry clientComputerRegistry = new ClientComputerRegistry();
-    public static final ServerComputerRegistry serverComputerRegistry = new ServerComputerRegistry();
-
-    // Logging
     public static final Logger log = LoggerFactory.getLogger( MOD_ID );
 
     public ComputerCraft()

src/main/java/dan200/computercraft/ComputerCraftAPIImpl.java

@@ -5,7 +5,9 @@
  */
 package dan200.computercraft;
 
-import dan200.computercraft.api.ComputerCraftAPI.IComputerCraftAPI;
+import com.google.auto.service.AutoService;
+import dan200.computercraft.api.detail.BlockReference;
+import dan200.computercraft.api.detail.DetailRegistry;
 import dan200.computercraft.api.detail.IDetailProvider;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
@@ -21,23 +23,30 @@ import dan200.computercraft.core.apis.ApiFactories;
 import dan200.computercraft.core.asm.GenericMethod;
 import dan200.computercraft.core.filesystem.FileMount;
 import dan200.computercraft.core.filesystem.ResourceMount;
+import dan200.computercraft.impl.ComputerCraftAPIService;
+import dan200.computercraft.impl.detail.DetailRegistryImpl;
 import dan200.computercraft.shared.BundledRedstone;
 import dan200.computercraft.shared.MediaProviders;
 import dan200.computercraft.shared.Peripherals;
+import dan200.computercraft.shared.computer.core.ServerContext;
 import dan200.computercraft.shared.peripheral.generic.GenericPeripheralProvider;
-import dan200.computercraft.shared.peripheral.generic.data.DetailProviders;
+import dan200.computercraft.shared.peripheral.generic.data.BlockData;
+import dan200.computercraft.shared.peripheral.generic.data.FluidData;
+import dan200.computercraft.shared.peripheral.generic.data.ItemData;
 import dan200.computercraft.shared.peripheral.modem.wireless.WirelessNetwork;
-import dan200.computercraft.shared.util.IDAssigner;
 import dan200.computercraft.shared.wired.WiredNode;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.packs.resources.ResourceManager;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.BlockGetter;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
+import net.minecraftforge.fluids.FluidStack;
 import net.minecraftforge.fml.ModList;
 import net.minecraftforge.server.ServerLifecycleHooks;
 
@@ -48,19 +57,18 @@ import java.io.InputStream;
 
 import static dan200.computercraft.shared.Capabilities.CAPABILITY_WIRED_ELEMENT;
 
-public final class ComputerCraftAPIImpl implements IComputerCraftAPI
+@AutoService( ComputerCraftAPIService.class )
+public final class ComputerCraftAPIImpl implements ComputerCraftAPIService
 {
-    public static final ComputerCraftAPIImpl INSTANCE = new ComputerCraftAPIImpl();
+    private final DetailRegistry<ItemStack> itemStackDetails = new DetailRegistryImpl<>( ItemData::fillBasic );
+    private final DetailRegistry<BlockReference> blockDetails = new DetailRegistryImpl<>( BlockData::fillBasic );
+    private final DetailRegistry<FluidStack> fluidStackDetails = new DetailRegistryImpl<>( FluidData::fillBasic );
 
     private String version;
 
-    private ComputerCraftAPIImpl()
+    public static InputStream getResourceFile( MinecraftServer server, String domain, String subPath )
     {
-    }
-
-    public static InputStream getResourceFile( String domain, String subPath )
-    {
-        var manager = ServerLifecycleHooks.getCurrentServer().getResourceManager();
+        ResourceManager manager = server.getResourceManager();
         var resource = manager.getResource( new ResourceLocation( domain, subPath ) ).orElse( null );
         if( resource == null ) return null;
         try
@@ -86,7 +94,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
     @Override
     public int createUniqueNumberedSaveDir( @Nonnull Level world, @Nonnull String parentSubPath )
     {
-        return IDAssigner.getNextId( parentSubPath );
+        return ServerContext.get( world.getServer() ).getNextId( parentSubPath );
     }
 
     @Override
@@ -94,7 +102,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
     {
         try
         {
-            return new FileMount( new File( IDAssigner.getDir(), subPath ), capacity );
+            return new FileMount( new File( ServerContext.get( world.getServer() ).storageDir().toFile(), subPath ), capacity );
         }
         catch( Exception e )
         {
@@ -160,9 +168,26 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
     }
 
     @Override
+    @Deprecated
+    @SuppressWarnings( "unchecked" )
     public <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider )
     {
-        DetailProviders.registerProvider( type, provider );
+        if( type == ItemStack.class )
+        {
+            itemStackDetails.addProvider( (IDetailProvider<ItemStack>) provider );
+        }
+        else if( type == BlockReference.class )
+        {
+            blockDetails.addProvider( (IDetailProvider<BlockReference>) provider );
+        }
+        else if( type == FluidStack.class )
+        {
+            itemStackDetails.addProvider( (IDetailProvider<ItemStack>) provider );
+        }
+        else
+        {
+            throw new IllegalArgumentException( "Unknown detail provider " + type );
+        }
     }
 
     @Nonnull
@@ -179,4 +204,22 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
         BlockEntity tile = world.getBlockEntity( pos );
         return tile == null ? LazyOptional.empty() : tile.getCapability( CAPABILITY_WIRED_ELEMENT, side );
     }
+
+    @Override
+    public DetailRegistry<ItemStack> getItemStackDetailRegistry()
+    {
+        return itemStackDetails;
+    }
+
+    @Override
+    public DetailRegistry<BlockReference> getBlockInWorldDetailRegistry()
+    {
+        return blockDetails;
+    }
+
+    @Override
+    public DetailRegistry<FluidStack> getFluidStackDetailRegistry()
+    {
+        return fluidStackDetails;
+    }
 }

src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -6,6 +6,7 @@
 package dan200.computercraft.api;
 
 import dan200.computercraft.api.detail.BlockReference;
+import dan200.computercraft.api.detail.DetailRegistry;
 import dan200.computercraft.api.detail.IDetailProvider;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
@@ -20,6 +21,7 @@ import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralProvider;
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
+import dan200.computercraft.impl.ComputerCraftAPIService;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.world.item.ItemStack;
@@ -34,7 +36,7 @@ import javax.annotation.Nullable;
 
 /**
  * The static entry point to the ComputerCraft API.
- *
+ * <p>
  * Members in this class must be called after mod_ComputerCraft has been initialised, but may be called before it is
  * fully loaded.
  */
@@ -50,13 +52,13 @@ public final class ComputerCraftAPI
 
     /**
      * Creates a numbered directory in a subfolder of the save directory for a given world, and returns that number.
-     *
+     * <p>
      * Use in conjunction with createSaveDirMount() to create a unique place for your peripherals or media items to store files.
      *
      * @param world         The world for which the save dir should be created. This should be the server side world object.
      * @param parentSubPath The folder path within the save directory where the new directory should be created. eg: "computercraft/disk"
      * @return The numerical value of the name of the new folder, or -1 if the folder could not be created for some reason.
-     *
+     * <p>
      * eg: if createUniqueNumberedSaveDir( world, "computer/disk" ) was called returns 42, then "computer/disk/42" is now
      * available for writing.
      * @see #createSaveDirMount(Level, String, long)
@@ -68,7 +70,7 @@ public final class ComputerCraftAPI
 
     /**
      * Creates a file system mount that maps to a subfolder of the save directory for a given world, and returns it.
-     *
+     * <p>
      * Use in conjunction with IComputerAccess.mount() or IComputerAccess.mountWritable() to mount a folder from the
      * users save directory onto a computers file system.
      *
@@ -92,10 +94,10 @@ public final class ComputerCraftAPI
 
     /**
      * Creates a file system mount to a resource folder, and returns it.
-     *
+     * <p>
      * Use in conjunction with {@link IComputerAccess#mount} or {@link IComputerAccess#mountWritable} to mount a
      * resource folder onto a computer's file system.
-     *
+     * <p>
      * The files in this mount will be a combination of files in all mod jar, and data packs that contain
      * resources with the same domain and path. For instance, ComputerCraft's resources are stored in
      * "/data/computercraft/lua/rom". We construct a mount for that with
@@ -208,7 +210,9 @@ public final class ComputerCraftAPI
      *                 {@link FluidStack} or {@link ItemStack}.
      * @param provider The detail provider to register.
      * @param <T>      The type of object that this provider can provide details for.
+     * @deprecated Use {@link DetailRegistry#addProvider(IDetailProvider)} to register your provider.
      */
+    @Deprecated
     public static <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider )
     {
         getInstance().registerDetailProvider( type, provider );
@@ -242,60 +246,9 @@ public final class ComputerCraftAPI
         return getInstance().getWiredElementAt( world, pos, side );
     }
 
-    private static IComputerCraftAPI instance;
-
     @Nonnull
-    private static IComputerCraftAPI getInstance()
+    private static ComputerCraftAPIService getInstance()
     {
-        if( instance != null ) return instance;
-
-        try
-        {
-            return instance = (IComputerCraftAPI) Class.forName( "dan200.computercraft.ComputerCraftAPIImpl" )
-                .getField( "INSTANCE" ).get( null );
-        }
-        catch( ReflectiveOperationException e )
-        {
-            throw new IllegalStateException( "Cannot find ComputerCraft API", e );
-        }
-    }
-
-    public interface IComputerCraftAPI
-    {
-        @Nonnull
-        String getInstalledVersion();
-
-        int createUniqueNumberedSaveDir( @Nonnull Level world, @Nonnull String parentSubPath );
-
-        @Nullable
-        IWritableMount createSaveDirMount( @Nonnull Level world, @Nonnull String subPath, long capacity );
-
-        @Nullable
-        IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath );
-
-        void registerPeripheralProvider( @Nonnull IPeripheralProvider provider );
-
-        void registerGenericSource( @Nonnull GenericSource source );
-
-        void registerGenericCapability( @Nonnull Capability<?> capability );
-
-        void registerBundledRedstoneProvider( @Nonnull IBundledRedstoneProvider provider );
-
-        int getBundledRedstoneOutput( @Nonnull Level world, @Nonnull BlockPos pos, @Nonnull Direction side );
-
-        void registerMediaProvider( @Nonnull IMediaProvider provider );
-
-        @Nonnull
-        IPacketNetwork getWirelessNetwork();
-
-        void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
-
-        <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider );
-
-        @Nonnull
-        IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
-
-        @Nonnull
-        LazyOptional<IWiredElement> getWiredElementAt( @Nonnull BlockGetter world, @Nonnull BlockPos pos, @Nonnull Direction side );
+        return ComputerCraftAPIService.get();
     }
 }

src/main/java/dan200/computercraft/api/client/ComputerCraftAPIClient.java

@@ -8,6 +8,7 @@ package dan200.computercraft.api.client;
 import dan200.computercraft.api.client.turtle.TurtleUpgradeModeller;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
+import dan200.computercraft.impl.client.ComputerCraftAPIClientService;
 import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent;
 
 import javax.annotation.Nonnull;
@@ -20,7 +21,7 @@ public final class ComputerCraftAPIClient
 
     /**
      * Register a {@link TurtleUpgradeModeller} for a class of turtle upgrades.
-     *
+     * <p>
      * This may be called at any point after registry creation, though it is recommended to call it within {@link FMLClientSetupEvent}.
      *
      * @param serialiser The turtle upgrade serialiser.
@@ -32,26 +33,9 @@ public final class ComputerCraftAPIClient
         getInstance().registerTurtleUpgradeModeller( serialiser, modeller );
     }
 
-    private static IComputerCraftAPIClient instance;
-
     @Nonnull
-    private static IComputerCraftAPIClient getInstance()
+    private static ComputerCraftAPIClientService getInstance()
     {
-        if( instance != null ) return instance;
-
-        try
-        {
-            return instance = (IComputerCraftAPIClient) Class.forName( "dan200.computercraft.client.ComputerCraftAPIClientImpl" )
-                .getField( "INSTANCE" ).get( null );
-        }
-        catch( ReflectiveOperationException e )
-        {
-            throw new IllegalStateException( "Cannot find ComputerCraft API", e );
-        }
-    }
-
-    public interface IComputerCraftAPIClient
-    {
-        <T extends ITurtleUpgrade> void registerTurtleUpgradeModeller( @Nonnull TurtleUpgradeSerialiser<T> serialiser, @Nonnull TurtleUpgradeModeller<T> modeller );
+        return ComputerCraftAPIClientService.get();
     }
 }

src/main/java/dan200/computercraft/api/client/TransformedModel.java

@@ -10,6 +10,7 @@ import net.minecraft.client.Minecraft;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.client.resources.model.ModelManager;
 import net.minecraft.client.resources.model.ModelResourceLocation;
+import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.item.ItemStack;
 
 import javax.annotation.Nonnull;
@@ -41,6 +42,12 @@ public final class TransformedModel
         return new TransformedModel( modelManager.getModel( location ) );
     }
 
+    public static TransformedModel of( @Nonnull ResourceLocation location )
+    {
+        ModelManager modelManager = Minecraft.getInstance().getModelManager();
+        return new TransformedModel( modelManager.getModel( location ) );
+    }
+
     public static TransformedModel of( @Nonnull ItemStack item, @Nonnull Transformation transform )
     {
         BakedModel model = Minecraft.getInstance().getItemRenderer().getItemModelShaper().getItemModel( item );

src/main/java/dan200/computercraft/api/client/turtle/TurtleUpgradeModeller.java

@@ -12,6 +12,7 @@ import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
 import net.minecraft.client.resources.model.ModelResourceLocation;
+import net.minecraft.resources.ResourceLocation;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -26,7 +27,7 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade>
 {
     /**
      * Obtain the model to be used when rendering a turtle peripheral.
-     *
+     * <p>
      * When the current turtle is {@literal null}, this function should be constant for a given upgrade and side.
      *
      * @param upgrade The upgrade that you're getting the model for.
@@ -40,7 +41,7 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade>
     /**
      * A basic {@link TurtleUpgradeModeller} which renders using the upgrade's {@linkplain ITurtleUpgrade#getCraftingItem()
      * crafting item}.
-     *
+     * <p>
      * This uses appropriate transformations for "flat" items, namely those extending the {@literal minecraft:item/generated}
      * model type. It will not appear correct for 3D models with additional depth, such as blocks.
      *
@@ -65,4 +66,17 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade>
     {
         return ( upgrade, turtle, side ) -> TransformedModel.of( side == TurtleSide.LEFT ? left : right );
     }
+
+    /**
+     * Construct a {@link TurtleUpgradeModeller} which has a single model for the left and right side.
+     *
+     * @param left  The model to use on the left.
+     * @param right The model to use on the right.
+     * @param <T>   The type of the turtle upgrade.
+     * @return The constructed modeller.
+     */
+    static <T extends ITurtleUpgrade> TurtleUpgradeModeller<T> sided( ResourceLocation left, ResourceLocation right )
+    {
+        return ( upgrade, turtle, side ) -> TransformedModel.of( side == TurtleSide.LEFT ? left : right );
+    }
 }

src/main/java/dan200/computercraft/api/detail/BasicItemDetailProvider.java

@@ -49,7 +49,7 @@ public abstract class BasicItemDetailProvider<T> implements IDetailProvider<Item
     /**
      * Provide additional details for the given {@link Item} and {@link ItemStack}. This method is called by
      * {@code turtle.getItemDetail()}. New properties should be added to the given {@link Map}, {@code data}.
-     *
+     * <p>
      * This method is always called on the server thread, so it is safe to interact with the world here, but you should
      * take care to avoid long blocking operations as this will stall the server and other computers.
      *

src/main/java/dan200/computercraft/api/detail/DetailRegistries.java

@@ -0,0 +1,32 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.detail;
+
+import dan200.computercraft.impl.ComputerCraftAPIService;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.block.Block;
+import net.minecraftforge.fluids.FluidStack;
+
+/**
+ * {@link DetailRegistry}s for built-in Minecraft types.
+ */
+public class DetailRegistries
+{
+    /**
+     * Provides details for {@link ItemStack}s.
+     */
+    public static final DetailRegistry<ItemStack> ITEM_STACK = ComputerCraftAPIService.get().getItemStackDetailRegistry();
+
+    /**
+     * Provides details for {@link BlockReference}, a reference to a {@link Block} in the world.
+     */
+    public static final DetailRegistry<BlockReference> BLOCK_IN_WORLD = ComputerCraftAPIService.get().getBlockInWorldDetailRegistry();
+
+    /**
+     * Provides details for {@link FluidStack}.
+     */
+    public static final DetailRegistry<FluidStack> FLUID_STACK = ComputerCraftAPIService.get().getFluidStackDetailRegistry();
+}

src/main/java/dan200/computercraft/api/detail/DetailRegistry.java

@@ -0,0 +1,49 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.detail;
+
+import org.jetbrains.annotations.ApiStatus;
+
+import java.util.Map;
+
+/**
+ * A registry which provides computer-visible detail about in-game objects such as blocks, items or fluids.
+ * <p>
+ * These are used by computer methods such as {@code turtle.getItemDetail()} or {@code turtle.inspect()}.
+ * <p>
+ * Specific instances of this registry are available from {@link DetailRegistries} and loader-specific versions
+ * also in this package.
+ *
+ * @param <T> The type of object that this registry provides details for.
+ */
+@ApiStatus.NonExtendable
+public interface DetailRegistry<T>
+{
+    /**
+     * Registers a detail provider.
+     *
+     * @param provider The detail provider to register.
+     * @see IDetailProvider
+     */
+    void addProvider( IDetailProvider<T> provider );
+
+    /**
+     * Compute basic details about an object. This is cheaper than computing all details operation, and so is suitable
+     * for when you need to compute the details for a large number of values.
+     *
+     * @param object The object to get details for.
+     * @return The basic details.
+     */
+    Map<String, Object> getBasicDetails( T object );
+
+    /**
+     * Compute all details about an object, using {@link #getBasicDetails(Object)} and any registered providers.
+     *
+     * @param object The object to get details for.
+     * @return The computed details.
+     */
+    Map<String, Object> getDetails( T object );
+}

src/main/java/dan200/computercraft/api/detail/IDetailProvider.java

@@ -9,10 +9,13 @@ import javax.annotation.Nonnull;
 import java.util.Map;
 
 /**
- * This interface is used to provide details about a block, fluid, or item.
+ * Provide details about a block, fluid, or item.
+ * <p>
+ * When implementing this interface, be careful to only expose information the player can see through normal gameplay.
+ * Computers shouldn't break progression or mechanics of other mods.
  *
  * @param <T> The type of object that this provider can provide details for.
- * @see dan200.computercraft.api.ComputerCraftAPI#registerDetailProvider(Class, IDetailProvider)
+ * @see DetailRegistry
  */
 @FunctionalInterface
 public interface IDetailProvider<T>
@@ -21,7 +24,7 @@ public interface IDetailProvider<T>
      * Provide additional details for the given object. This method is called by functions such as
      * {@code turtle.getItemDetail()} and {@code turtle.inspect()}. New properties should be added to the given
      * {@link Map}, {@code data}.
-     *
+     * <p>
      * This method is always called on the server thread, so it is safe to interact with the world here, but you should
      * take care to avoid long blocking operations as this will stall the server and other computers.
      *

src/main/java/dan200/computercraft/api/filesystem/FileAttributes.java

@@ -11,20 +11,14 @@ import java.time.Instant;
 
 /**
  * A simple version of {@link BasicFileAttributes}, which provides what information a {@link IMount} already exposes.
+ *
+ * @param isDirectory Whether this filesystem entry is a directory.
+ * @param size        The size of the file.
  */
-final class FileAttributes implements BasicFileAttributes
+record FileAttributes(boolean isDirectory, long size) implements BasicFileAttributes
 {
     private static final FileTime EPOCH = FileTime.from( Instant.EPOCH );
 
-    private final boolean isDirectory;
-    private final long size;
-
-    FileAttributes( boolean isDirectory, long size )
-    {
-        this.isDirectory = isDirectory;
-        this.size = size;
-    }
-
     @Override
     public FileTime lastModifiedTime()
     {
@@ -49,12 +43,6 @@ final class FileAttributes implements BasicFileAttributes
         return !isDirectory;
     }
 
-    @Override
-    public boolean isDirectory()
-    {
-        return isDirectory;
-    }
-
     @Override
     public boolean isSymbolicLink()
     {
@@ -67,12 +55,6 @@ final class FileAttributes implements BasicFileAttributes
         return false;
     }
 
-    @Override
-    public long size()
-    {
-        return size;
-    }
-
     @Override
     public Object fileKey()
     {

src/main/java/dan200/computercraft/api/filesystem/FileOperationException.java

@@ -12,7 +12,7 @@ import java.util.Objects;
 
 /**
  * An {@link IOException} which occurred on a specific file.
- *
+ * <p>
  * This may be thrown from a {@link IMount} or {@link IWritableMount} to give more information about a failure.
  */
 public class FileOperationException extends IOException

src/main/java/dan200/computercraft/api/filesystem/IFileSystem.java

@@ -9,7 +9,7 @@ import java.io.IOException;
 
 /**
  * Provides a mount of the entire computer's file system.
- *
+ * <p>
  * This exists for use by various APIs - one should not attempt to mount it.
  */
 public interface IFileSystem extends IWritableMount

src/main/java/dan200/computercraft/api/filesystem/IMount.java

@@ -18,7 +18,7 @@ import java.util.List;
 /**
  * Represents a read only part of a virtual filesystem that can be mounted onto a computer using
  * {@link IComputerAccess#mount(String, IMount)}.
- *
+ * <p>
  * Ready made implementations of this interface can be created using
  * {@link ComputerCraftAPI#createSaveDirMount(Level, String, long)} or
  * {@link ComputerCraftAPI#createResourceMount(String, String)}, or you're free to implement it yourselves!

src/main/java/dan200/computercraft/api/filesystem/IWritableMount.java

@@ -18,7 +18,7 @@ import java.util.OptionalLong;
 /**
  * Represents a part of a virtual filesystem that can be mounted onto a computer using {@link IComputerAccess#mount(String, IMount)}
  * or {@link IComputerAccess#mountWritable(String, IWritableMount)}, that can also be written to.
- *
+ * <p>
  * Ready made implementations of this interface can be created using
  * {@link ComputerCraftAPI#createSaveDirMount(Level, String, long)}, or you're free to implement it yourselves!
  *

src/main/java/dan200/computercraft/api/lua/GenericSource.java

@@ -17,17 +17,17 @@ import javax.annotation.Nonnull;
 
 /**
  * A generic source of {@link LuaMethod} functions.
- *
+ * <p>
  * Unlike normal objects ({@link IDynamicLuaObject} or {@link IPeripheral}), methods do not target this object but
  * instead are defined as {@code static} and accept their target as the first parameter. This allows you to inject
  * methods onto objects you do not own, as well as declaring methods for a specific "trait" (for instance, a
  * {@link Capability}).
- *
+ * <p>
  * Currently the "generic peripheral" system is incompatible with normal peripherals. Normal {@link IPeripheralProvider}
  * or {@link IPeripheral} implementations take priority. Tile entities which use this system are given a peripheral name
  * determined by their id, rather than any peripheral provider. This will hopefully change in the future, once a suitable
  * design has been established.
- *
+ * <p>
  * For example, the main CC: Tweaked mod defines a generic source for inventories, which works on {@link IItemHandler}s:
  *
  * <pre>{@code
@@ -49,7 +49,7 @@ public interface GenericSource
 {
     /**
      * A unique identifier for this generic source.
-     *
+     * <p>
      * This is currently unused, but may be used in the future to allow disabling specific sources. It is recommended
      * to return an identifier using your mod's ID.
      *

src/main/java/dan200/computercraft/api/lua/IArguments.java

@@ -69,8 +69,8 @@ public interface IArguments
     default double getDouble( int index ) throws LuaException
     {
         Object value = get( index );
-        if( !(value instanceof Number) ) throw LuaValues.badArgumentOf( index, "number", value );
-        return ((Number) value).doubleValue();
+        if( !(value instanceof Number number) ) throw LuaValues.badArgumentOf( index, "number", value );
+        return number.doubleValue();
     }
 
     /**
@@ -95,8 +95,8 @@ public interface IArguments
     default long getLong( int index ) throws LuaException
     {
         Object value = get( index );
-        if( !(value instanceof Number) ) throw LuaValues.badArgumentOf( index, "number", value );
-        return LuaValues.checkFiniteNum( index, (Number) value ).longValue();
+        if( !(value instanceof Number number) ) throw LuaValues.badArgumentOf( index, "number", value );
+        return LuaValues.checkFiniteNum( index, number ).longValue();
     }
 
     /**
@@ -121,8 +121,8 @@ public interface IArguments
     default boolean getBoolean( int index ) throws LuaException
     {
         Object value = get( index );
-        if( !(value instanceof Boolean) ) throw LuaValues.badArgumentOf( index, "boolean", value );
-        return (Boolean) value;
+        if( !(value instanceof Boolean bool) ) throw LuaValues.badArgumentOf( index, "boolean", value );
+        return bool;
     }
 
     /**
@@ -136,8 +136,8 @@ public interface IArguments
     default String getString( int index ) throws LuaException
     {
         Object value = get( index );
-        if( !(value instanceof String) ) throw LuaValues.badArgumentOf( index, "string", value );
-        return (String) value;
+        if( !(value instanceof String string) ) throw LuaValues.badArgumentOf( index, "string", value );
+        return string;
     }
 
     /**
@@ -185,7 +185,7 @@ public interface IArguments
 
     /**
      * Get an argument as a table in an unsafe manner.
-     *
+     * <p>
      * Classes implementing this interface may choose to implement a more optimised version which does not copy the
      * table, instead returning a wrapper version, making it more efficient. However, the caller must guarantee that
      * they do not access the table the computer thread (and so should not be used with main-thread functions) or once
@@ -213,8 +213,8 @@ public interface IArguments
     {
         Object value = get( index );
         if( value == null ) return Optional.empty();
-        if( !(value instanceof Number) ) throw LuaValues.badArgumentOf( index, "number", value );
-        return Optional.of( ((Number) value).doubleValue() );
+        if( !(value instanceof Number number) ) throw LuaValues.badArgumentOf( index, "number", value );
+        return Optional.of( number.doubleValue() );
     }
 
     /**
@@ -241,8 +241,8 @@ public interface IArguments
     {
         Object value = get( index );
         if( value == null ) return Optional.empty();
-        if( !(value instanceof Number) ) throw LuaValues.badArgumentOf( index, "number", value );
-        return Optional.of( LuaValues.checkFiniteNum( index, (Number) value ).longValue() );
+        if( !(value instanceof Number number) ) throw LuaValues.badArgumentOf( index, "number", value );
+        return Optional.of( LuaValues.checkFiniteNum( index, number ).longValue() );
     }
 
     /**
@@ -270,8 +270,8 @@ public interface IArguments
     {
         Object value = get( index );
         if( value == null ) return Optional.empty();
-        if( !(value instanceof Boolean) ) throw LuaValues.badArgumentOf( index, "boolean", value );
-        return Optional.of( (Boolean) value );
+        if( !(value instanceof Boolean bool) ) throw LuaValues.badArgumentOf( index, "boolean", value );
+        return Optional.of( bool );
     }
 
     /**
@@ -285,8 +285,8 @@ public interface IArguments
     {
         Object value = get( index );
         if( value == null ) return Optional.empty();
-        if( !(value instanceof String) ) throw LuaValues.badArgumentOf( index, "string", value );
-        return Optional.of( (String) value );
+        if( !(value instanceof String string) ) throw LuaValues.badArgumentOf( index, "string", value );
+        return Optional.of( string );
     }
 
     /**
@@ -334,7 +334,7 @@ public interface IArguments
 
     /**
      * Get an argument as a table in an unsafe manner.
-     *
+     * <p>
      * Classes implementing this interface may choose to implement a more optimised version which does not copy the
      * table, instead returning a wrapper version, making it more efficient. However, the caller must guarantee that
      * they do not access off the computer thread (and so should not be used with main-thread functions) or once the

src/main/java/dan200/computercraft/api/lua/IDynamicLuaObject.java

@@ -11,7 +11,7 @@ import javax.annotation.Nonnull;
 
 /**
  * An interface for representing custom objects returned by peripherals or other Lua objects.
- *
+ * <p>
  * Generally, one does not need to implement this type - it is sufficient to return an object with some methods
  * annotated with {@link LuaFunction}. {@link IDynamicLuaObject} is useful when you wish your available methods to
  * change at runtime.

src/main/java/dan200/computercraft/api/lua/ILuaAPI.java

@@ -10,7 +10,7 @@ import dan200.computercraft.api.ComputerCraftAPI;
 /**
  * Represents a Lua object which is stored as a global variable on computer startup. This must either provide
  * {@link LuaFunction} annotated functions or implement {@link IDynamicLuaObject}.
- *
+ * <p>
  * Before implementing this interface, consider alternative methods of providing methods. It is generally preferred
  * to use peripherals to provide functionality to users.
  *
@@ -28,7 +28,7 @@ public interface ILuaAPI
 
     /**
      * Called when the computer is turned on.
-     *
+     * <p>
      * One should only interact with the file system.
      */
     default void startup()
@@ -44,7 +44,7 @@ public interface ILuaAPI
 
     /**
      * Called when the computer is turned off or unloaded.
-     *
+     * <p>
      * This should reset the state of the object, disposing any remaining file handles, or other resources.
      */
     default void shutdown()

src/main/java/dan200/computercraft/api/lua/ILuaContext.java

@@ -17,7 +17,7 @@ public interface ILuaContext
      * Queue a task to be executed on the main server thread at the beginning of next tick, but do not wait for it to
      * complete. This should be used when you need to interact with the world in a thread-safe manner but do not care
      * about the result or you wish to run asynchronously.
-     *
+     * <p>
      * When the task has finished, it will enqueue a {@code task_completed} event, which takes the task id, a success
      * value and the return values, or an error message if it failed.
      *
@@ -31,7 +31,7 @@ public interface ILuaContext
     /**
      * Queue a task to be executed on the main server thread at the beginning of next tick, waiting for it to complete.
      * This should be used when you need to interact with the world in a thread-safe manner.
-     *
+     * <p>
      * Note that the return values of your task are handled as events, meaning more complex objects such as maps or
      * {@link IDynamicLuaObject} will not preserve their identities.
      *

src/main/java/dan200/computercraft/api/lua/LuaFunction.java

@@ -14,7 +14,7 @@ import java.util.Optional;
 
 /**
  * Used to mark a Java function which is callable from Lua.
- *
+ * <p>
  * Methods annotated with {@link LuaFunction} must be public final instance methods. They can have any number of
  * parameters, but they must be of the following types:
  *
@@ -24,12 +24,12 @@ import java.util.Optional;
  *   <li>
  *     Alternatively, one may specify the desired arguments as normal parameters and the argument parsing code will
  *     be generated automatically.
- *
+ * <p>
  *     Each parameter must be one of the given types supported by {@link IArguments} (for instance, {@link int} or
  *     {@link Map}). Optional values are supported by accepting a parameter of type {@link Optional}.
  *   </li>
  * </ul>
- *
+ * <p>
  * This function may return {@link MethodResult}. However, if you simply return a value (rather than having to yield),
  * you may return {@code void}, a single value (either an object or a primitive like {@code int}) or array of objects.
  * These will be treated the same as {@link MethodResult#of()}, {@link MethodResult#of(Object)} and
@@ -58,7 +58,7 @@ public @interface LuaFunction
 
     /**
      * Allow using "unsafe" arguments, such {@link IArguments#getTableUnsafe(int)}.
-     *
+     * <p>
      * This is incompatible with {@link #mainThread()}.
      *
      * @return Whether this function supports unsafe arguments.

src/main/java/dan200/computercraft/api/lua/LuaTable.java

@@ -35,9 +35,8 @@ public interface LuaTable<K, V> extends Map<K, V>
     default long getLong( int index ) throws LuaException
     {
         Object value = get( (double) index );
-        if( !(value instanceof Number) ) throw badTableItem( index, "number", getType( value ) );
+        if( !(value instanceof Number number) ) throw badTableItem( index, "number", getType( value ) );
 
-        Number number = (Number) value;
         double asDouble = number.doubleValue();
         if( !Double.isFinite( asDouble ) ) throw badTableItem( index, "number", getNumericType( asDouble ) );
         return number.longValue();
@@ -53,9 +52,8 @@ public interface LuaTable<K, V> extends Map<K, V>
     default long getLong( String key ) throws LuaException
     {
         Object value = get( key );
-        if( !(value instanceof Number) ) throw badField( key, "number", getType( value ) );
+        if( !(value instanceof Number number) ) throw badField( key, "number", getType( value ) );
 
-        Number number = (Number) value;
         double asDouble = number.doubleValue();
         if( !Double.isFinite( asDouble ) ) throw badField( key, "number", getNumericType( asDouble ) );
         return number.longValue();

src/main/java/dan200/computercraft/api/lua/MethodResult.java

@@ -16,7 +16,7 @@ import java.util.Objects;
 
 /**
  * The result of invoking a Lua method.
- *
+ * <p>
  * Method results either return a value immediately ({@link #of(Object...)} or yield control to the parent coroutine.
  * When the current coroutine is resumed, we invoke the provided {@link ILuaCallback#resume(Object[])} callback.
  */
@@ -55,11 +55,11 @@ public final class MethodResult
 
     /**
      * Return a single value immediately.
-     *
+     * <p>
      * Integers, doubles, floats, strings, booleans, {@link Map}, {@link Collection}s, arrays and {@code null} will be
      * converted to their corresponding Lua type. {@code byte[]} and {@link ByteBuffer} will be treated as binary
      * strings. {@link ILuaFunction} will be treated as a function.
-     *
+     * <p>
      * In order to provide a custom object with methods, one may return a {@link IDynamicLuaObject}, or an arbitrary
      * class with {@link LuaFunction} annotations. Anything else will be converted to {@code nil}.
      *

src/main/java/dan200/computercraft/api/media/IMedia.java

@@ -16,7 +16,7 @@ import javax.annotation.Nullable;
 
 /**
  * Represents an item that can be placed in a disk drive and used by a Computer.
- *
+ * <p>
  * Implement this interface on your {@link Item} class to allow it to be used in the drive. Alternatively, register
  * a {@link IMediaProvider}.
  */

src/main/java/dan200/computercraft/api/network/IPacketReceiver.java

@@ -33,7 +33,7 @@ public interface IPacketReceiver
 
     /**
      * Get the maximum distance this receiver can send and receive messages.
-     *
+     * <p>
      * When determining whether a receiver can receive a message, the largest distance of the packet and receiver is
      * used - ensuring it is within range. If the packet or receiver is inter-dimensional, then the packet will always
      * be received.
@@ -47,7 +47,7 @@ public interface IPacketReceiver
 
     /**
      * Determine whether this receiver can receive packets from other dimensions.
-     *
+     * <p>
      * A device will receive an inter-dimensional packet if either it or the sending device is inter-dimensional.
      *
      * @return Whether this receiver receives packets from other dimensions.

src/main/java/dan200/computercraft/api/network/wired/IWiredElement.java

@@ -11,11 +11,11 @@ import javax.annotation.Nonnull;
 
 /**
  * An object which may be part of a wired network.
- *
+ * <p>
  * Elements should construct a node using {@link ComputerCraftAPI#createWiredNodeForElement(IWiredElement)}. This acts
  * as a proxy for all network objects. Whilst the node may change networks, an element's node should remain constant
  * for its lifespan.
- *
+ * <p>
  * Elements are generally tied to a block or tile entity in world. In such as case, one should provide the
  * {@link IWiredElement} capability for the appropriate sides.
  */

src/main/java/dan200/computercraft/api/network/wired/IWiredNetwork.java

@@ -13,12 +13,12 @@ import java.util.Map;
 /**
  * A wired network is composed of one of more {@link IWiredNode}s, a set of connections between them, and a series
  * of peripherals.
- *
+ * <p>
  * Networks from a connected graph. This means there is some path between all nodes on the network. Further more, if
  * there is some path between two nodes then they must be on the same network. {@link IWiredNetwork} will automatically
  * handle the merging and splitting of networks (and thus changing of available nodes and peripherals) as connections
  * change.
- *
+ * <p>
  * This does mean one can not rely on the network remaining consistent between subsequent operations. Consequently,
  * it is generally preferred to use the methods provided by {@link IWiredNode}.
  *
@@ -28,7 +28,7 @@ public interface IWiredNetwork
 {
     /**
      * Create a connection between two nodes.
-     *
+     * <p>
      * This should only be used on the server thread.
      *
      * @param left  The first node to connect
@@ -43,7 +43,7 @@ public interface IWiredNetwork
 
     /**
      * Destroy a connection between this node and another.
-     *
+     * <p>
      * This should only be used on the server thread.
      *
      * @param left  The first node in the connection.
@@ -58,7 +58,7 @@ public interface IWiredNetwork
 
     /**
      * Sever all connections this node has, removing it from this network.
-     *
+     * <p>
      * This should only be used on the server thread. You should only call this on nodes
      * that your network element owns.
      *
@@ -72,7 +72,7 @@ public interface IWiredNetwork
 
     /**
      * Update the peripherals a node provides.
-     *
+     * <p>
      * This should only be used on the server thread. You should only call this on nodes
      * that your network element owns.
      *

src/main/java/dan200/computercraft/api/network/wired/IWiredNode.java

@@ -13,14 +13,14 @@ import java.util.Map;
 
 /**
  * Wired nodes act as a layer between {@link IWiredElement}s and {@link IWiredNetwork}s.
- *
+ * <p>
  * Firstly, a node acts as a packet network, capable of sending and receiving modem messages to connected nodes. These
  * methods may be safely used on any thread.
- *
+ * <p>
  * When sending a packet, the system will attempt to find the shortest path between the two nodes based on their
  * element's position. Note that packet senders and receivers can have different locations from their associated
  * element: the distance between the two will be added to the total packet's distance.
- *
+ * <p>
  * Wired nodes also provide several convenience methods for interacting with a wired network. These should only ever
  * be used on the main server thread.
  */
@@ -37,7 +37,7 @@ public interface IWiredNode extends IPacketNetwork
     /**
      * The network this node is currently connected to. Note that this may change
      * after any network operation, so it should not be cached.
-     *
+     * <p>
      * This should only be used on the server thread.
      *
      * @return This node's network.
@@ -47,7 +47,7 @@ public interface IWiredNode extends IPacketNetwork
 
     /**
      * Create a connection from this node to another.
-     *
+     * <p>
      * This should only be used on the server thread.
      *
      * @param node The other node to connect to.
@@ -62,7 +62,7 @@ public interface IWiredNode extends IPacketNetwork
 
     /**
      * Destroy a connection between this node and another.
-     *
+     * <p>
      * This should only be used on the server thread.
      *
      * @param node The other node to disconnect from.
@@ -78,7 +78,7 @@ public interface IWiredNode extends IPacketNetwork
 
     /**
      * Sever all connections this node has, removing it from this network.
-     *
+     * <p>
      * This should only be used on the server thread. You should only call this on nodes
      * that your network element owns.
      *
@@ -94,7 +94,7 @@ public interface IWiredNode extends IPacketNetwork
 
     /**
      * Mark this node's peripherals as having changed.
-     *
+     * <p>
      * This should only be used on the server thread. You should only call this on nodes
      * that your network element owns.
      *

src/main/java/dan200/computercraft/api/network/wired/IWiredSender.java

@@ -11,7 +11,7 @@ import javax.annotation.Nonnull;
 
 /**
  * An object on a {@link IWiredNetwork} capable of sending packets.
- *
+ * <p>
  * Unlike a regular {@link IPacketSender}, this must be associated with the node you are attempting to
  * to send the packet from.
  */
@@ -19,7 +19,7 @@ public interface IWiredSender extends IPacketSender
 {
     /**
      * The node in the network representing this object.
-     *
+     * <p>
      * This should be used as a proxy for the main network. One should send packets
      * and register receivers through this object.
      *

src/main/java/dan200/computercraft/api/peripheral/GenericPeripheral.java

@@ -13,7 +13,7 @@ import javax.annotation.Nonnull;
 
 /**
  * A {@link GenericSource} which provides methods for a peripheral.
- *
+ * <p>
  * Unlike a {@link GenericSource}, all methods <strong>should</strong> target the same type, for instance a
  * {@link BlockEntity} subclass or a capability interface. This is not currently enforced.
  */
@@ -21,13 +21,13 @@ public interface GenericPeripheral extends GenericSource
 {
     /**
      * Get the type of the exposed peripheral.
-     *
+     * <p>
      * Unlike normal {@link IPeripheral}s, {@link GenericPeripheral} do not have to have a type. By default, the
      * resulting peripheral uses the resource name of the wrapped {@link BlockEntity} (for instance {@code minecraft:chest}).
-     *
+     * <p>
      * However, in some cases it may be more appropriate to specify a more readable name. Overriding this method allows
      * you to do so.
-     *
+     * <p>
      * When multiple {@link GenericPeripheral}s return a non-empty peripheral type for a single tile entity, the
      * lexicographically smallest will be chosen. In order to avoid this conflict, this method should only be
      * implemented when your peripheral targets a single tile entity <strong>AND</strong> it's likely that you're the

src/main/java/dan200/computercraft/api/peripheral/IComputerAccess.java

@@ -105,11 +105,11 @@ public interface IComputerAccess
     /**
      * Unmounts a directory previously mounted onto the computers file system by {@link #mount(String, IMount)}
      * or {@link #mountWritable(String, IWritableMount)}.
-     *
+     * <p>
      * When a directory is unmounted, it will disappear from the computers file system, and the user will no longer be
      * able to access it. All directories mounted by a mount or mountWritable are automatically unmounted when the
      * peripheral is attached if they have not been explicitly unmounted.
-     *
+     * <p>
      * Note that you cannot unmount another peripheral's mounts.
      *
      * @param location The desired location in the computers file system of the directory to unmount.
@@ -124,7 +124,7 @@ public interface IComputerAccess
 
     /**
      * Returns the numerical ID of this computer.
-     *
+     * <p>
      * This is the same number obtained by calling {@code os.getComputerID()} or running the "id" program from lua,
      * and is guaranteed unique. This number will be positive.
      *
@@ -145,7 +145,7 @@ public interface IComputerAccess
      * @param arguments In addition to a name, you may pass an array of extra arguments to the event, that will
      *                  be supplied as extra return values to os.pullEvent(). Objects in the array will be converted
      *                  to lua data types in the same fashion as the return values of IPeripheral.callMethod().
-     *
+     *                  <p>
      *                  You may supply {@code null} to indicate that no arguments are to be supplied.
      * @throws NotAttachedException If the peripheral has been detached.
      * @see MethodResult#pullEvent(String, ILuaCallback)
@@ -167,7 +167,7 @@ public interface IComputerAccess
 
     /**
      * Get a set of peripherals that this computer access can "see", along with their attachment name.
-     *
+     * <p>
      * This may include other peripherals on the wired network or peripherals on other sides of the computer.
      *
      * @return All reachable peripherals
@@ -191,12 +191,12 @@ public interface IComputerAccess
 
     /**
      * Get a {@link IWorkMonitor} for tasks your peripheral might execute on the main (server) thread.
-     *
+     * <p>
      * This should be used to ensure your peripheral integrates with ComputerCraft's monitoring and limiting of how much
      * server time each computer consumes. You should not need to use this if you use
      * {@link ILuaContext#issueMainThreadTask(ILuaTask)} - this is intended for mods with their own system for running
      * work on the main thread.
-     *
+     * <p>
      * Please note that the returned implementation is <em>not</em> thread-safe, and should only be used from the main
      * thread.
      *

src/main/java/dan200/computercraft/api/peripheral/IDynamicPeripheral.java

@@ -11,7 +11,7 @@ import javax.annotation.Nonnull;
 
 /**
  * A peripheral whose methods are not known at runtime.
- *
+ * <p>
  * This behaves similarly to {@link IDynamicLuaObject}, though also accepting the current {@link IComputerAccess}.
  * Generally one may use {@link LuaFunction} instead of implementing this interface.
  */
@@ -30,7 +30,7 @@ public interface IDynamicPeripheral extends IPeripheral
     /**
      * This is called when a lua program on an attached computer calls {@code peripheral.call()} with
      * one of the methods exposed by {@link #getMethodNames()}.
-     *
+     * <p>
      * Be aware that this will be called from the ComputerCraft Lua thread, and must be thread-safe when interacting
      * with Minecraft objects.
      *

src/main/java/dan200/computercraft/api/peripheral/IPeripheral.java

@@ -15,10 +15,10 @@ import java.util.Set;
 
 /**
  * The interface that defines a peripheral.
- *
+ * <p>
  * In order to expose a peripheral for your block or tile entity, you may either attach a {@link Capability}, or
  * register a {@link IPeripheralProvider}. This <em>cannot</em> be implemented {@link IPeripheral} directly on the tile.
- *
+ * <p>
  * Peripherals should provide a series of methods to the user, either using {@link LuaFunction} or by implementing
  * {@link IDynamicPeripheral}.
  */
@@ -47,15 +47,15 @@ public interface IPeripheral
 
     /**
      * Is called when when a computer is attaching to the peripheral.
-     *
+     * <p>
      * This will occur when a peripheral is placed next to an active computer, when a computer is turned on next to a
      * peripheral, when a turtle travels into a square next to a peripheral, or when a wired modem adjacent to this
      * peripheral is does any of the above.
-     *
+     * <p>
      * Between calls to attach and {@link #detach}, the attached computer can make method calls on the peripheral using
      * {@code peripheral.call()}. This method can be used to keep track of which computers are attached to the
      * peripheral, or to take action when attachment occurs.
-     *
+     * <p>
      * Be aware that will be called from both the server thread and ComputerCraft Lua thread, and so must be thread-safe
      * and reentrant.
      *
@@ -69,14 +69,14 @@ public interface IPeripheral
 
     /**
      * Called when a computer is detaching from the peripheral.
-     *
+     * <p>
      * This will occur when a computer shuts down, when the peripheral is removed while attached to computers, when a
      * turtle moves away from a block attached to a peripheral, or when a wired modem adjacent to this peripheral is
      * detached.
-     *
+     * <p>
      * This method can be used to keep track of which computers are attached to the peripheral, or to take action when
      * detachment occurs.
-     *
+     * <p>
      * Be aware that this will be called from both the server and ComputerCraft Lua thread, and must be thread-safe
      * and reentrant.
      *
@@ -102,7 +102,7 @@ public interface IPeripheral
 
     /**
      * Determine whether this peripheral is equivalent to another one.
-     *
+     * <p>
      * The minimal example should at least check whether they are the same object. However, you may wish to check if
      * they point to the same block or tile entity.
      *

src/main/java/dan200/computercraft/api/peripheral/IPeripheralProvider.java

@@ -15,7 +15,7 @@ import javax.annotation.Nonnull;
 
 /**
  * This interface is used to create peripheral implementations for blocks.
- *
+ * <p>
  * If you have a {@link BlockEntity} which acts as a peripheral, you may alternatively expose the {@link IPeripheral}
  * capability.
  *

src/main/java/dan200/computercraft/api/peripheral/IWorkMonitor.java

@@ -12,14 +12,14 @@ import java.util.concurrent.TimeUnit;
 /**
  * Monitors "work" associated with a computer, keeping track of how much a computer has done, and ensuring every
  * computer receives a fair share of any processing time.
- *
+ * <p>
  * This is primarily intended for work done by peripherals on the main thread (such as on a tile entity's tick), but
  * could be used for other purposes (such as complex computations done on another thread).
- *
+ * <p>
  * Before running a task, one should call {@link #canWork()} to determine if the computer is currently allowed to
  * execute work. If that returns true, you should execute the task and use {@link #trackWork(long, TimeUnit)} to inform
  * the monitor how long that task took.
- *
+ * <p>
  * Alternatively, use {@link #runWork(Runnable)} to run and keep track of work.
  *
  * @see IComputerAccess#getMainThreadMonitor()
@@ -35,7 +35,7 @@ public interface IWorkMonitor
 
     /**
      * If the owning computer is currently allowed to execute work, and has ample time to do so.
-     *
+     * <p>
      * This is effectively a more restrictive form of {@link #canWork()}. One should use that in order to determine if
      * you may do an initial piece of work, and shouldWork to determine if any additional task may be performed.
      *

src/main/java/dan200/computercraft/api/peripheral/PeripheralType.java

@@ -16,7 +16,7 @@ import java.util.Set;
 
 /**
  * The type of a {@link GenericPeripheral}.
- *
+ * <p>
  * When determining the final type of the resulting peripheral, the union of all types is taken, with the
  * lexicographically smallest non-empty name being chosen.
  */

src/main/java/dan200/computercraft/api/pocket/AbstractPocketUpgrade.java

@@ -13,7 +13,7 @@ import javax.annotation.Nonnull;
 
 /**
  * A base class for {@link IPocketUpgrade}s.
- *
+ * <p>
  * One does not have to use this, but it does provide a convenient template.
  */
 public abstract class AbstractPocketUpgrade implements IPocketUpgrade

src/main/java/dan200/computercraft/api/pocket/IPocketAccess.java

@@ -21,7 +21,7 @@ public interface IPocketAccess
 {
     /**
      * Gets the entity holding this item.
-     *
+     * <p>
      * This must be called on the server thread.
      *
      * @return The holding entity, or {@code null} if none exists.
@@ -67,7 +67,7 @@ public interface IPocketAccess
 
     /**
      * Get the upgrade-specific NBT.
-     *
+     * <p>
      * This is persisted between computer reboots and chunk loads.
      *
      * @return The upgrade's NBT.

src/main/java/dan200/computercraft/api/pocket/IPocketUpgrade.java

@@ -14,10 +14,10 @@ import javax.annotation.Nullable;
 
 /**
  * A peripheral which can be equipped to the back side of a pocket computer.
- *
+ * <p>
  * Pocket upgrades are defined in two stages. First, on creates a {@link IPocketUpgrade} subclass and corresponding
  * {@link PocketUpgradeSerialiser} instance, which are then registered in a Forge registry.
- *
+ * <p>
  * You then write a JSON file in your mod's {@literal data/} folder. This is then parsed when the world is loaded, and
  * the upgrade registered internally. See the documentation in {@link PocketUpgradeSerialiser} for details on this process
  * and where files should be located.
@@ -28,7 +28,7 @@ public interface IPocketUpgrade extends IUpgradeBase
 {
     /**
      * Creates a peripheral for the pocket computer.
-     *
+     * <p>
      * The peripheral created will be stored for the lifetime of the upgrade, will be passed an argument to
      * {@link #update(IPocketAccess, IPeripheral)} and will be attached, detached and have methods called in the same
      * manner as an ordinary peripheral.

src/main/java/dan200/computercraft/api/pocket/PocketUpgradeDataProvider.java

@@ -14,7 +14,7 @@ import java.util.function.Consumer;
 
 /**
  * A data provider to generate pocket computer upgrades.
- *
+ * <p>
  * This should be subclassed and registered to a {@link DataGenerator}. Override the {@link #addUpgrades(Consumer)} function,
  * construct each upgrade, and pass them off to the provided consumer to generate them.
  *

src/main/java/dan200/computercraft/api/pocket/PocketUpgradeSerialiser.java

@@ -25,7 +25,7 @@ import java.util.function.Function;
 
 /**
  * Reads a {@link IPocketUpgrade} from disk and reads/writes it to a network packet.
- *
+ * <p>
  * This follows the same format as {@link dan200.computercraft.api.turtle.TurtleUpgradeSerialiser} - consult the
  * documentation there for more information.
  *
@@ -37,7 +37,7 @@ public interface PocketUpgradeSerialiser<T extends IPocketUpgrade> extends Upgra
 {
     /**
      * The ID for the associated registry.
-     *
+     * <p>
      * This is largely intended for use with Forge Registry methods/classes, such as {@link DeferredRegister} and
      * {@link RegistryManager#getRegistry(ResourceKey)}.
      *
@@ -59,7 +59,7 @@ public interface PocketUpgradeSerialiser<T extends IPocketUpgrade> extends Upgra
     /**
      * Create an upgrade serialiser for a simple upgrade. This is similar to a {@link SimpleRecipeSerializer}, but for
      * upgrades.
-     *
+     * <p>
      * If you might want to vary the item, it's suggested you use {@link #simpleWithCustomItem(BiFunction)} instead.
      *
      * @param factory Generate a new upgrade with a specific ID.
@@ -69,7 +69,7 @@ public interface PocketUpgradeSerialiser<T extends IPocketUpgrade> extends Upgra
     @Nonnull
     static <T extends IPocketUpgrade> PocketUpgradeSerialiser<T> simple( @Nonnull Function<ResourceLocation, T> factory )
     {
-        class Impl extends SimpleSerialiser<T> implements PocketUpgradeSerialiser<T>
+        final class Impl extends SimpleSerialiser<T> implements PocketUpgradeSerialiser<T>
         {
             private Impl( Function<ResourceLocation, T> constructor )
             {
@@ -92,7 +92,7 @@ public interface PocketUpgradeSerialiser<T extends IPocketUpgrade> extends Upgra
     @Nonnull
     static <T extends IPocketUpgrade> PocketUpgradeSerialiser<T> simpleWithCustomItem( @Nonnull BiFunction<ResourceLocation, ItemStack, T> factory )
     {
-        class Impl extends SerialiserWithCraftingItem<T> implements PocketUpgradeSerialiser<T>
+        final class Impl extends SerialiserWithCraftingItem<T> implements PocketUpgradeSerialiser<T>
         {
             private Impl( BiFunction<ResourceLocation, ItemStack, T> factory )
             {

src/main/java/dan200/computercraft/api/turtle/AbstractTurtleUpgrade.java

@@ -13,7 +13,7 @@ import javax.annotation.Nonnull;
 
 /**
  * A base class for {@link ITurtleUpgrade}s.
- *
+ * <p>
  * One does not have to use this, but it does provide a convenient template.
  */
 public abstract class AbstractTurtleUpgrade implements ITurtleUpgrade

src/main/java/dan200/computercraft/api/turtle/ITurtleAccess.java

@@ -22,7 +22,7 @@ import javax.annotation.Nullable;
 
 /**
  * The interface passed to turtle by turtles, providing methods that they can call.
- *
+ * <p>
  * This should not be implemented by your classes. Do not interact with turtles except via this interface and
  * {@link ITurtleUpgrade}.
  */
@@ -46,7 +46,7 @@ public interface ITurtleAccess
 
     /**
      * Attempt to move this turtle to a new position.
-     *
+     * <p>
      * This will preserve the turtle's internal state, such as it's inventory, computer and upgrades. It should
      * be used before playing a movement animation using {@link #playAnimation(TurtleAnimation)}.
      *
@@ -144,7 +144,7 @@ public interface ITurtleAccess
 
     /**
      * Get the inventory of this turtle.
-     *
+     * <p>
      * Note: this inventory should only be accessed and modified on the server thread.
      *
      * @return This turtle's inventory
@@ -155,7 +155,7 @@ public interface ITurtleAccess
 
     /**
      * Get the inventory of this turtle as an {@link IItemHandlerModifiable}.
-     *
+     * <p>
      * Note: this inventory should only be accessed and modified on the server thread.
      *
      * @return This turtle's inventory
@@ -278,7 +278,7 @@ public interface ITurtleAccess
 
     /**
      * Get an upgrade-specific NBT compound, which can be used to store arbitrary data.
-     *
+     * <p>
      * This will be persisted across turtle restarts and chunk loads, as well as being synced to the client. You must
      * call {@link #updateUpgradeNBTData(TurtleSide)} after modifying it.
      *

src/main/java/dan200/computercraft/api/turtle/ITurtleCommand.java

@@ -17,7 +17,7 @@ public interface ITurtleCommand
 {
     /**
      * Will be called by the turtle on the main thread when it is time to execute the custom command.
-     *
+     * <p>
      * The handler should either perform the work of the command, and return success, or return
      * failure with an error message to indicate the command cannot be executed at this time.
      *

src/main/java/dan200/computercraft/api/turtle/ITurtleUpgrade.java

@@ -17,10 +17,10 @@ import javax.annotation.Nullable;
 /**
  * The primary interface for defining an update for Turtles. A turtle update can either be a new tool, or a new
  * peripheral.
- *
+ * <p>
  * Turtle upgrades are defined in two stages. First, one creates a {@link ITurtleUpgrade} subclass and corresponding
  * {@link TurtleUpgradeSerialiser} instance, which are then registered in a Forge registry.
- *
+ * <p>
  * You then write a JSON file in your mod's {@literal data/} folder. This is then parsed when the world is loaded, and
  * the upgrade registered internally. See the documentation in {@link TurtleUpgradeSerialiser} for details on this process
  * and where files should be located.
@@ -40,7 +40,7 @@ public interface ITurtleUpgrade extends IUpgradeBase
 
     /**
      * Will only be called for peripheral upgrades. Creates a peripheral for a turtle being placed using this upgrade.
-     *
+     * <p>
      * The peripheral created will be stored for the lifetime of the upgrade and will be passed as an argument to
      * {@link #update(ITurtleAccess, TurtleSide)}. It will be attached, detached and have methods called in the same
      * manner as a Computer peripheral.
@@ -59,7 +59,7 @@ public interface ITurtleUpgrade extends IUpgradeBase
     /**
      * Will only be called for Tool turtle. Called when turtle.dig() or turtle.attack() is called
      * by the turtle, and the tool is required to do some work.
-     *
+     * <p>
      * Conforming implementations should fire {@link BlockEvent.BreakEvent} for digging {@link AttackEntityEvent}
      * for attacking.
      *

src/main/java/dan200/computercraft/api/turtle/TurtleAnimation.java

@@ -7,7 +7,7 @@ package dan200.computercraft.api.turtle;
 
 /**
  * An animation a turtle will play between executing commands.
- *
+ * <p>
  * Each animation takes 8 ticks to complete unless otherwise specified.
  *
  * @see ITurtleAccess#playAnimation(TurtleAnimation)

src/main/java/dan200/computercraft/api/turtle/TurtleUpgradeDataProvider.java

@@ -22,7 +22,7 @@ import java.util.function.Consumer;
 
 /**
  * A data provider to generate turtle upgrades.
- *
+ * <p>
  * This should be subclassed and registered to a {@link DataGenerator}. Override the {@link #addUpgrades(Consumer)} function,
  * construct each upgrade, and pass them off to the provided consumer to generate them.
  *

src/main/java/dan200/computercraft/api/turtle/TurtleUpgradeSerialiser.java

@@ -28,10 +28,10 @@ import java.util.function.Function;
 
 /**
  * Reads a {@link ITurtleUpgrade} from disk and reads/writes it to a network packet.
- *
+ * <p>
  * These should be registered in a {@link IForgeRegistry} while the game is loading, much like {@link RecipeSerializer}s.
  * It is suggested you use a {@link DeferredRegister}.
- *
+ * <p>
  * If your turtle upgrade doesn't have any associated configurable parameters (like most upgrades), you can use
  * {@link #simple(Function)} or {@link #simpleWithCustomItem(BiFunction)} to create a basic upgrade serialiser.
  *
@@ -46,7 +46,7 @@ import java.util.function.Function;
  * // Then in your constructor
  * SERIALISERS.register( bus );
  * }</pre>
- *
+ * <p>
  * We can then define a new upgrade using JSON by placing the following in
  * {@literal data/<my_mod>/computercraft/turtle_upgrades/<my_upgrade_id>.json}}.
  *
@@ -55,7 +55,7 @@ import java.util.function.Function;
  *     "type": my_mod:my_upgrade",
  * }
  * }</pre>
- *
+ * <p>
  * Finally, we need to register a model for our upgrade. This is done with
  * {@link ComputerCraftAPIClient#registerTurtleUpgradeModeller(TurtleUpgradeSerialiser, TurtleUpgradeModeller)}:
  *
@@ -63,7 +63,7 @@ import java.util.function.Function;
  * // Register our model inside FMLClientSetupEvent
  * ComputerCraftAPIClient.registerTurtleUpgradeModeller(MY_UPGRADE.get(), TurtleUpgradeModeller.flatItem())
  * }</pre>
- *
+ * <p>
  * {@link TurtleUpgradeDataProvider} provides a data provider to aid with generating these JSON files.
  *
  * @param <T> The type of turtle upgrade this is responsible for serialising.
@@ -75,7 +75,7 @@ public interface TurtleUpgradeSerialiser<T extends ITurtleUpgrade> extends Upgra
 {
     /**
      * The ID for the associated registry.
-     *
+     * <p>
      * This is largely intended for use with Forge Registry methods/classes, such as {@link DeferredRegister} and
      * {@link RegistryManager#getRegistry(ResourceKey)}.
      *
@@ -97,7 +97,7 @@ public interface TurtleUpgradeSerialiser<T extends ITurtleUpgrade> extends Upgra
     /**
      * Create an upgrade serialiser for a simple upgrade. This is similar to a {@link SimpleRecipeSerializer}, but for
      * upgrades.
-     *
+     * <p>
      * If you might want to vary the item, it's suggested you use {@link #simpleWithCustomItem(BiFunction)} instead.
      *
      * @param factory Generate a new upgrade with a specific ID.
@@ -107,7 +107,7 @@ public interface TurtleUpgradeSerialiser<T extends ITurtleUpgrade> extends Upgra
     @Nonnull
     static <T extends ITurtleUpgrade> TurtleUpgradeSerialiser<T> simple( @Nonnull Function<ResourceLocation, T> factory )
     {
-        class Impl extends SimpleSerialiser<T> implements TurtleUpgradeSerialiser<T>
+        final class Impl extends SimpleSerialiser<T> implements TurtleUpgradeSerialiser<T>
         {
             private Impl( Function<ResourceLocation, T> constructor )
             {
@@ -130,7 +130,7 @@ public interface TurtleUpgradeSerialiser<T extends ITurtleUpgrade> extends Upgra
     @Nonnull
     static <T extends ITurtleUpgrade> TurtleUpgradeSerialiser<T> simpleWithCustomItem( @Nonnull BiFunction<ResourceLocation, ItemStack, T> factory )
     {
-        class Impl extends SerialiserWithCraftingItem<T> implements TurtleUpgradeSerialiser<T>
+        final class Impl extends SerialiserWithCraftingItem<T> implements TurtleUpgradeSerialiser<T>
         {
             private Impl( BiFunction<ResourceLocation, ItemStack, T> factory )
             {

src/main/java/dan200/computercraft/api/turtle/event/TurtleEvent.java

@@ -14,7 +14,7 @@ import java.util.Objects;
 /**
  * A base class for all events concerning a turtle. This will only ever constructed and fired on the server side,
  * so sever specific methods on {@link ITurtleAccess} are safe to use.
- *
+ * <p>
  * You should generally not need to subscribe to this event, preferring one of the more specific classes.
  */
 public abstract class TurtleEvent extends Event

src/main/java/dan200/computercraft/api/turtle/event/TurtleRefuelEvent.java

@@ -14,7 +14,7 @@ import java.util.Objects;
 
 /**
  * Fired when a turtle attempts to refuel from an item.
- *
+ * <p>
  * One may use {@link #setHandler(Handler)} to register a custom fuel provider for a given item.
  */
 public class TurtleRefuelEvent extends TurtleEvent
@@ -32,7 +32,7 @@ public class TurtleRefuelEvent extends TurtleEvent
 
     /**
      * Get the stack we are attempting to refuel from.
-     *
+     * <p>
      * Do not modify the returned stack - all modifications should be done within the {@link Handler}.
      *
      * @return The stack to refuel from.
@@ -56,7 +56,7 @@ public class TurtleRefuelEvent extends TurtleEvent
 
     /**
      * Set the refuel handler for this stack.
-     *
+     * <p>
      * You should call this if you can actually refuel from this item, and ideally only if there are no existing
      * handlers.
      *

src/main/java/dan200/computercraft/api/upgrades/IUpgradeBase.java

@@ -22,7 +22,7 @@ public interface IUpgradeBase
     /**
      * Gets a unique identifier representing this type of turtle upgrade. eg: "computercraft:wireless_modem"
      * or "my_mod:my_upgrade".
-     *
+     * <p>
      * You should use a unique resource domain to ensure this upgrade is uniquely identified.
      * The upgrade will fail registration if an already used ID is specified.
      *
@@ -33,7 +33,7 @@ public interface IUpgradeBase
 
     /**
      * Return an unlocalised string to describe this type of computer in item names.
-     *
+     * <p>
      * Examples of built-in adjectives are "Wireless", "Mining" and "Crafty".
      *
      * @return The localisation key for this upgrade's adjective.
@@ -45,7 +45,7 @@ public interface IUpgradeBase
      * Return an item stack representing the type of item that a computer must be crafted
      * with to create a version which holds this upgrade. This item stack is also used
      * to determine the upgrade given by {@code turtle.equipLeft()} or {@code pocket.equipBack()}
-     *
+     * <p>
      * This should be constant over a session (or at least a datapack reload). It is recommended
      * that you cache the stack too, in order to prevent constructing it every time the method
      * is called.
@@ -57,11 +57,11 @@ public interface IUpgradeBase
 
     /**
      * Determine if an item is suitable for being used for this upgrade.
-     *
+     * <p>
      * When un-equipping an upgrade, we return {@link #getCraftingItem()} rather than
      * the original stack. In order to prevent people losing items with enchantments (or
      * repairing items with non-0 damage), we impose additional checks on the item.
-     *
+     * <p>
      * The default check requires that any non-capability NBT is exactly the same as the
      * crafting item, but this may be relaxed for your upgrade.
      *

src/main/java/dan200/computercraft/api/upgrades/UpgradeSerialiser.java

@@ -16,7 +16,7 @@ import javax.annotation.Nonnull;
 /**
  * Base interface for upgrade serialisers. This should generally not be implemented directly, instead implementing one
  * of {@link TurtleUpgradeSerialiser} or {@link PocketUpgradeSerialiser}.
- *
+ * <p>
  * However, it may sometimes be useful to implement this if you have some shared logic between upgrade types.
  *
  * @param <T> The upgrade that this class can serialise and deserialise.

src/main/java/dan200/computercraft/client/ClientHooks.java

@@ -6,6 +6,7 @@
 package dan200.computercraft.client;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.pocket.ClientPocketComputers;
 import dan200.computercraft.client.sound.SpeakerManager;
 import dan200.computercraft.shared.peripheral.monitor.ClientMonitor;
 import net.minecraftforge.api.distmarker.Dist;
@@ -30,12 +31,12 @@ public class ClientHooks
     @SubscribeEvent
     public static void onLogIn( ClientPlayerNetworkEvent.LoggingIn event )
     {
-        ComputerCraft.clientComputerRegistry.reset();
+        ClientPocketComputers.reset();
     }
 
     @SubscribeEvent
     public static void onLogOut( ClientPlayerNetworkEvent.LoggingOut event )
     {
-        ComputerCraft.clientComputerRegistry.reset();
+        ClientPocketComputers.reset();
     }
 }

src/main/java/dan200/computercraft/client/ClientRegistry.java

@@ -9,6 +9,7 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.client.ComputerCraftAPIClient;
 import dan200.computercraft.api.client.turtle.TurtleUpgradeModeller;
 import dan200.computercraft.client.gui.*;
+import dan200.computercraft.client.pocket.ClientPocketComputers;
 import dan200.computercraft.client.render.TileEntityMonitorRenderer;
 import dan200.computercraft.client.render.TileEntityTurtleRenderer;
 import dan200.computercraft.client.render.TurtleModelLoader;
@@ -19,13 +20,11 @@ import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
 import dan200.computercraft.shared.media.items.ItemDisk;
 import dan200.computercraft.shared.media.items.ItemTreasureDisk;
-import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
 import net.minecraft.client.gui.screens.MenuScreens;
 import net.minecraft.client.renderer.blockentity.BlockEntityRenderers;
 import net.minecraft.client.renderer.item.ItemProperties;
 import net.minecraft.client.renderer.item.ItemPropertyFunction;
-import net.minecraft.client.resources.model.ModelResourceLocation;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.item.Item;
 import net.minecraftforge.api.distmarker.Dist;
@@ -45,24 +44,25 @@ public final class ClientRegistry
 {
     private static final String[] EXTRA_MODELS = new String[] {
         // Turtle upgrades
-        "turtle_modem_normal_off_left",
-        "turtle_modem_normal_on_left",
-        "turtle_modem_normal_off_right",
-        "turtle_modem_normal_on_right",
+        "block/turtle_modem_normal_off_left",
+        "block/turtle_modem_normal_on_left",
+        "block/turtle_modem_normal_off_right",
+        "block/turtle_modem_normal_on_right",
 
-        "turtle_modem_advanced_off_left",
-        "turtle_modem_advanced_on_left",
-        "turtle_modem_advanced_off_right",
-        "turtle_modem_advanced_on_right",
-        "turtle_crafting_table_left",
-        "turtle_crafting_table_right",
+        "block/turtle_modem_advanced_off_left",
+        "block/turtle_modem_advanced_on_left",
+        "block/turtle_modem_advanced_off_right",
+        "block/turtle_modem_advanced_on_right",
 
-        "turtle_speaker_upgrade_left",
-        "turtle_speaker_upgrade_right",
+        "block/turtle_crafting_table_left",
+        "block/turtle_crafting_table_right",
+
+        "block/turtle_speaker_left",
+        "block/turtle_speaker_right",
 
         // Turtle block renderer
-        "turtle_colour",
-        "turtle_elf_overlay",
+        "block/turtle_colour",
+        "block/turtle_elf_overlay",
     };
 
     private ClientRegistry() {}
@@ -78,7 +78,7 @@ public final class ClientRegistry
     {
         for( String model : EXTRA_MODELS )
         {
-            event.register( new ModelResourceLocation( new ResourceLocation( ComputerCraft.MOD_ID, model ), "inventory" ) );
+            event.register( new ResourceLocation( ComputerCraft.MOD_ID, model ) );
         }
     }
 
@@ -111,7 +111,7 @@ public final class ClientRegistry
                     return IColouredItem.getColourBasic( stack );
                 case 2: // Light colour
                 {
-                    int light = ItemPocketComputer.getLightState( stack );
+                    int light = ClientPocketComputers.get( stack ).getLightState();
                     return light == -1 ? Colour.BLACK.getHex() : light;
                 }
             }
@@ -134,12 +134,12 @@ public final class ClientRegistry
         BlockEntityRenderers.register( Registry.ModBlockEntities.TURTLE_ADVANCED.get(), TileEntityTurtleRenderer::new );
 
         ComputerCraftAPIClient.registerTurtleUpgradeModeller( Registry.ModTurtleSerialisers.SPEAKER.get(), TurtleUpgradeModeller.sided(
-            new ModelResourceLocation( "computercraft:turtle_speaker_upgrade_left", "inventory" ),
-            new ModelResourceLocation( "computercraft:turtle_speaker_upgrade_right", "inventory" )
+            new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_speaker_left" ),
+            new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_speaker_right" )
         ) );
         ComputerCraftAPIClient.registerTurtleUpgradeModeller( Registry.ModTurtleSerialisers.WORKBENCH.get(), TurtleUpgradeModeller.sided(
-            new ModelResourceLocation( "computercraft:turtle_crafting_table_left", "inventory" ),
-            new ModelResourceLocation( "computercraft:turtle_crafting_table_right", "inventory" )
+            new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_crafting_table_left" ),
+            new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_crafting_table_right" )
         ) );
         ComputerCraftAPIClient.registerTurtleUpgradeModeller( Registry.ModTurtleSerialisers.WIRELESS_MODEM_NORMAL.get(), new TurtleModemModeller( false ) );
         ComputerCraftAPIClient.registerTurtleUpgradeModeller( Registry.ModTurtleSerialisers.WIRELESS_MODEM_ADVANCED.get(), new TurtleModemModeller( true ) );
@@ -149,7 +149,7 @@ public final class ClientRegistry
             registerContainers();
 
             registerItemProperty( "state",
-                ( stack, world, player, random ) -> ItemPocketComputer.getState( stack ).ordinal(),
+                ( stack, world, player, random ) -> ClientPocketComputers.get( stack ).getState().ordinal(),
                 Registry.ModItems.POCKET_COMPUTER_NORMAL, Registry.ModItems.POCKET_COMPUTER_ADVANCED
             );
             registerItemProperty( "coloured",
@@ -174,8 +174,8 @@ public final class ClientRegistry
     {
         // My IDE doesn't think so, but we do actually need these generics.
 
-        MenuScreens.<ContainerComputerBase, GuiComputer<ContainerComputerBase>>register( Registry.ModContainers.COMPUTER.get(), GuiComputer::create );
-        MenuScreens.<ContainerComputerBase, GuiComputer<ContainerComputerBase>>register( Registry.ModContainers.POCKET_COMPUTER.get(), GuiComputer::createPocket );
+        MenuScreens.<ContainerComputerBase, GuiComputer<ContainerComputerBase>>register( Registry.ModContainers.COMPUTER.get(), GuiComputer::new );
+        MenuScreens.<ContainerComputerBase, GuiComputer<ContainerComputerBase>>register( Registry.ModContainers.POCKET_COMPUTER.get(), GuiComputer::new );
         MenuScreens.<ContainerComputerBase, NoTermComputerScreen<ContainerComputerBase>>register( Registry.ModContainers.POCKET_COMPUTER_NO_TERM.get(), NoTermComputerScreen::new );
         MenuScreens.register( Registry.ModContainers.TURTLE.get(), GuiTurtle::new );
 
@@ -183,6 +183,6 @@ public final class ClientRegistry
         MenuScreens.register( Registry.ModContainers.DISK_DRIVE.get(), GuiDiskDrive::new );
         MenuScreens.register( Registry.ModContainers.PRINTOUT.get(), GuiPrintout::new );
 
-        MenuScreens.<ContainerViewComputer, GuiComputer<ContainerViewComputer>>register( Registry.ModContainers.VIEW_COMPUTER.get(), GuiComputer::createView );
+        MenuScreens.<ContainerViewComputer, GuiComputer<ContainerViewComputer>>register( Registry.ModContainers.VIEW_COMPUTER.get(), GuiComputer::new );
     }
 }

src/main/java/dan200/computercraft/client/ComputerCraftAPIClientImpl.java

@@ -5,22 +5,18 @@
  */
 package dan200.computercraft.client;
 
-import dan200.computercraft.api.client.ComputerCraftAPIClient;
+import com.google.auto.service.AutoService;
 import dan200.computercraft.api.client.turtle.TurtleUpgradeModeller;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
 import dan200.computercraft.client.turtle.TurtleUpgradeModellers;
+import dan200.computercraft.impl.client.ComputerCraftAPIClientService;
 
 import javax.annotation.Nonnull;
 
-public final class ComputerCraftAPIClientImpl implements ComputerCraftAPIClient.IComputerCraftAPIClient
+@AutoService( ComputerCraftAPIClientService.class )
+public final class ComputerCraftAPIClientImpl implements ComputerCraftAPIClientService
 {
-    public static final ComputerCraftAPIClientImpl INSTANCE = new ComputerCraftAPIClientImpl();
-
-    private ComputerCraftAPIClientImpl()
-    {
-    }
-
     @Override
     public <T extends ITurtleUpgrade> void registerTurtleUpgradeModeller( @Nonnull TurtleUpgradeSerialiser<T> serialiser, @Nonnull TurtleUpgradeModeller<T> modeller )
     {

src/main/java/dan200/computercraft/client/gui/ClientInputHandler.java

@@ -0,0 +1,92 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.gui;
+
+import dan200.computercraft.shared.computer.core.InputHandler;
+import dan200.computercraft.shared.computer.menu.ComputerMenu;
+import dan200.computercraft.shared.network.NetworkHandler;
+import dan200.computercraft.shared.network.server.ComputerActionServerMessage;
+import dan200.computercraft.shared.network.server.KeyEventServerMessage;
+import dan200.computercraft.shared.network.server.MouseEventServerMessage;
+import dan200.computercraft.shared.network.server.QueueEventServerMessage;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+
+import javax.annotation.Nullable;
+
+/**
+ * An {@link InputHandler} which for use on the client.
+ * <p>
+ * This queues events on the remote player's open {@link ComputerMenu}
+ */
+public final class ClientInputHandler implements InputHandler
+{
+    private final AbstractContainerMenu menu;
+
+    public ClientInputHandler( AbstractContainerMenu menu )
+    {
+        this.menu = menu;
+    }
+
+    @Override
+    public void turnOn()
+    {
+        NetworkHandler.sendToServer( new ComputerActionServerMessage( menu, ComputerActionServerMessage.Action.TURN_ON ) );
+    }
+
+    @Override
+    public void shutdown()
+    {
+        NetworkHandler.sendToServer( new ComputerActionServerMessage( menu, ComputerActionServerMessage.Action.SHUTDOWN ) );
+    }
+
+    @Override
+    public void reboot()
+    {
+        NetworkHandler.sendToServer( new ComputerActionServerMessage( menu, ComputerActionServerMessage.Action.REBOOT ) );
+    }
+
+    @Override
+    public void queueEvent( String event, @Nullable Object[] arguments )
+    {
+        NetworkHandler.sendToServer( new QueueEventServerMessage( menu, event, arguments ) );
+    }
+
+    @Override
+    public void keyDown( int key, boolean repeat )
+    {
+        NetworkHandler.sendToServer( new KeyEventServerMessage( menu, repeat ? KeyEventServerMessage.TYPE_REPEAT : KeyEventServerMessage.TYPE_DOWN, key ) );
+    }
+
+    @Override
+    public void keyUp( int key )
+    {
+        NetworkHandler.sendToServer( new KeyEventServerMessage( menu, KeyEventServerMessage.TYPE_UP, key ) );
+    }
+
+    @Override
+    public void mouseClick( int button, int x, int y )
+    {
+        NetworkHandler.sendToServer( new MouseEventServerMessage( menu, MouseEventServerMessage.TYPE_CLICK, button, x, y ) );
+    }
+
+    @Override
+    public void mouseUp( int button, int x, int y )
+    {
+        NetworkHandler.sendToServer( new MouseEventServerMessage( menu, MouseEventServerMessage.TYPE_UP, button, x, y ) );
+    }
+
+    @Override
+    public void mouseDrag( int button, int x, int y )
+    {
+        NetworkHandler.sendToServer( new MouseEventServerMessage( menu, MouseEventServerMessage.TYPE_DRAG, button, x, y ) );
+    }
+
+    @Override
+    public void mouseScroll( int direction, int x, int y )
+    {
+        NetworkHandler.sendToServer( new MouseEventServerMessage( menu, MouseEventServerMessage.TYPE_SCROLL, direction, x, y ) );
+    }
+}

src/main/java/dan200/computercraft/client/gui/ComputerScreenBase.java

@@ -10,8 +10,9 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.client.gui.widgets.DynamicImageButton;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
-import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
+import dan200.computercraft.shared.computer.core.InputHandler;
 import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import dan200.computercraft.shared.computer.upload.FileUpload;
 import dan200.computercraft.shared.computer.upload.UploadResult;
@@ -41,16 +42,18 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
     private static final Component OVERWRITE = Component.translatable( "gui.computercraft.upload.overwrite_button" );
 
     protected WidgetTerminal terminal;
-    protected final ClientComputer computer;
+    protected Terminal terminalData;
     protected final ComputerFamily family;
+    protected final InputHandler input;
 
     protected final int sidebarYOffset;
 
     public ComputerScreenBase( T container, Inventory player, Component title, int sidebarYOffset )
     {
         super( container, player, title );
-        computer = (ClientComputer) container.getComputer();
+        terminalData = container.getTerminal();
         family = container.getFamily();
+        input = new ClientInputHandler( menu );
         this.sidebarYOffset = sidebarYOffset;
     }
 
@@ -63,7 +66,7 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
         minecraft.keyboardHandler.setSendRepeatsToGui( true );
 
         terminal = addRenderableWidget( createTerminal() );
-        ComputerSidebar.addButtons( this, computer, this::addRenderableWidget, leftPos, topPos + sidebarYOffset );
+        ComputerSidebar.addButtons( this, menu::isOn, input, this::addRenderableWidget, leftPos, topPos + sidebarYOffset );
         setFocused( terminal );
     }
 
@@ -131,7 +134,7 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
     {
         if( files.isEmpty() ) return;
 
-        if( computer == null || !computer.isOn() )
+        if( !menu.isOn() )
         {
             alert( UploadResult.FAILED_TITLE, UploadResult.COMPUTER_OFF_MSG );
             return;
@@ -187,10 +190,7 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
             return;
         }
 
-        if( toUpload.size() > 0 )
-        {
-            UploadFileMessage.send( computer.getInstanceID(), toUpload );
-        }
+        if( toUpload.size() > 0 ) UploadFileMessage.send( menu, toUpload, NetworkHandler::sendToServer );
     }
 
     public void uploadResult( UploadResult result, Component message )
@@ -219,13 +219,13 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
     private void continueUpload()
     {
         if( minecraft.screen instanceof OptionScreen screen ) screen.disable();
-        NetworkHandler.sendToServer( new ContinueUploadMessage( computer.getInstanceID(), true ) );
+        NetworkHandler.sendToServer( new ContinueUploadMessage( menu, true ) );
     }
 
     private void cancelUpload()
     {
         minecraft.setScreen( this );
-        NetworkHandler.sendToServer( new ContinueUploadMessage( computer.getInstanceID(), false ) );
+        NetworkHandler.sendToServer( new ContinueUploadMessage( menu, false ) );
     }
 
     private void alert( Component title, Component message )

src/main/java/dan200/computercraft/client/gui/GuiComputer.java

@@ -6,12 +6,10 @@
 package dan200.computercraft.client.gui;
 
 import com.mojang.blaze3d.vertex.PoseStack;
-import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.client.render.ComputerBorderRenderer;
 import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
-import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.entity.player.Inventory;
 
@@ -22,54 +20,18 @@ import static dan200.computercraft.client.render.RenderTypes.FULL_BRIGHT_LIGHTMA
 
 public final class GuiComputer<T extends ContainerComputerBase> extends ComputerScreenBase<T>
 {
-    private final int termWidth;
-    private final int termHeight;
-
-    private GuiComputer(
-        T container, Inventory player, Component title, int termWidth, int termHeight
-    )
+    public GuiComputer( T container, Inventory player, Component title )
     {
         super( container, player, title, BORDER );
-        this.termWidth = termWidth;
-        this.termHeight = termHeight;
 
-        imageWidth = WidgetTerminal.getWidth( termWidth ) + BORDER * 2 + ComputerSidebar.WIDTH;
-        imageHeight = WidgetTerminal.getHeight( termHeight ) + BORDER * 2;
-    }
-
-    @Nonnull
-    public static GuiComputer<ContainerComputerBase> create( ContainerComputerBase container, Inventory inventory, Component component )
-    {
-        return new GuiComputer<>(
-            container, inventory, component,
-            ComputerCraft.computerTermWidth, ComputerCraft.computerTermHeight
-        );
-    }
-
-    @Nonnull
-    public static GuiComputer<ContainerComputerBase> createPocket( ContainerComputerBase container, Inventory inventory, Component component )
-    {
-        return new GuiComputer<>(
-            container, inventory, component,
-            ComputerCraft.pocketTermWidth, ComputerCraft.pocketTermHeight
-        );
-    }
-
-    @Nonnull
-    public static GuiComputer<ContainerViewComputer> createView( ContainerViewComputer container, Inventory inventory, Component component )
-    {
-        return new GuiComputer<>(
-            container, inventory, component,
-            container.getWidth(), container.getHeight()
-        );
+        imageWidth = WidgetTerminal.getWidth( terminalData.getWidth() ) + BORDER * 2 + ComputerSidebar.WIDTH;
+        imageHeight = WidgetTerminal.getHeight( terminalData.getHeight() ) + BORDER * 2;
     }
 
     @Override
     protected WidgetTerminal createTerminal()
     {
-        return new WidgetTerminal( computer,
-            leftPos + ComputerSidebar.WIDTH + BORDER, topPos + BORDER, termWidth, termHeight
-        );
+        return new WidgetTerminal( terminalData, input, leftPos + ComputerSidebar.WIDTH + BORDER, topPos + BORDER );
     }
 
     @Override

src/main/java/dan200/computercraft/client/gui/GuiTurtle.java

@@ -43,10 +43,7 @@ public class GuiTurtle extends ComputerScreenBase<ContainerTurtle>
     @Override
     protected WidgetTerminal createTerminal()
     {
-        return new WidgetTerminal(
-            computer, leftPos + BORDER + ComputerSidebar.WIDTH, topPos + BORDER,
-            ComputerCraft.turtleTermWidth, ComputerCraft.turtleTermHeight
-        );
+        return new WidgetTerminal( terminalData, input, leftPos + BORDER + ComputerSidebar.WIDTH, topPos + BORDER );
     }
 
     @Override

src/main/java/dan200/computercraft/client/gui/NoTermComputerScreen.java

@@ -6,9 +6,8 @@
 package dan200.computercraft.client.gui;
 
 import com.mojang.blaze3d.vertex.PoseStack;
-import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
-import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import net.minecraft.client.KeyMapping;
 import net.minecraft.client.gui.Font;
@@ -25,12 +24,14 @@ import java.util.List;
 public class NoTermComputerScreen<T extends ContainerComputerBase> extends Screen implements MenuAccess<T>
 {
     private final T menu;
+    private final Terminal terminalData;
     private WidgetTerminal terminal;
 
     public NoTermComputerScreen( T menu, Inventory player, Component title )
     {
         super( title );
         this.menu = menu;
+        terminalData = menu.getTerminal();
     }
 
     @Nonnull
@@ -53,7 +54,7 @@ public class NoTermComputerScreen<T extends ContainerComputerBase> extends Scree
         super.init();
         minecraft.keyboardHandler.setSendRepeatsToGui( true );
 
-        terminal = addWidget( new WidgetTerminal( (ClientComputer) menu.getComputer(), 0, 0, ComputerCraft.pocketTermWidth, ComputerCraft.pocketTermHeight ) );
+        terminal = addWidget( new WidgetTerminal( terminalData, new ClientInputHandler( menu ), 0, 0 ) );
         terminal.visible = false;
         terminal.active = false;
         setFocused( terminal );

src/main/java/dan200/computercraft/client/gui/OptionScreen.java

@@ -56,7 +56,7 @@ public final class OptionScreen extends Screen
 
     public static Screen unwrap( Screen screen )
     {
-        return screen instanceof OptionScreen ? ((OptionScreen) screen).getOriginalScreen() : screen;
+        return screen instanceof OptionScreen option ? option.getOriginalScreen() : screen;
     }
 
     @Override

src/main/java/dan200/computercraft/client/gui/widgets/ComputerSidebar.java

@@ -8,7 +8,7 @@ package dan200.computercraft.client.gui.widgets;
 import com.mojang.blaze3d.vertex.PoseStack;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.render.ComputerBorderRenderer;
-import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.shared.computer.core.InputHandler;
 import net.minecraft.ChatFormatting;
 import net.minecraft.client.gui.components.AbstractWidget;
 import net.minecraft.client.gui.screens.Screen;
@@ -16,6 +16,7 @@ import net.minecraft.network.chat.Component;
 import net.minecraft.resources.ResourceLocation;
 
 import java.util.Arrays;
+import java.util.function.BooleanSupplier;
 import java.util.function.Consumer;
 
 /**
@@ -44,15 +45,15 @@ public final class ComputerSidebar
     {
     }
 
-    public static void addButtons( Screen screen, ClientComputer computer, Consumer<AbstractWidget> add, int x, int y )
+    public static void addButtons( Screen screen, BooleanSupplier isOn, InputHandler input, Consumer<AbstractWidget> add, int x, int y )
     {
         x += CORNERS_BORDER + 1;
         y += CORNERS_BORDER + ICON_MARGIN;
 
         add.accept( new DynamicImageButton(
-            screen, x, y, ICON_WIDTH, ICON_HEIGHT, () -> computer.isOn() ? 15 : 1, 1, ICON_TEX_Y_DIFF,
-            TEXTURE, TEX_SIZE, TEX_SIZE, b -> toggleComputer( computer ),
-            () -> computer.isOn() ? Arrays.asList(
+            screen, x, y, ICON_WIDTH, ICON_HEIGHT, () -> isOn.getAsBoolean() ? 15 : 1, 1, ICON_TEX_Y_DIFF,
+            TEXTURE, TEX_SIZE, TEX_SIZE, b -> toggleComputer( isOn, input ),
+            () -> isOn.getAsBoolean() ? Arrays.asList(
                 Component.translatable( "gui.computercraft.tooltip.turn_off" ),
                 Component.translatable( "gui.computercraft.tooltip.turn_off.key" ).withStyle( ChatFormatting.GRAY )
             ) : Arrays.asList(
@@ -65,7 +66,7 @@ public final class ComputerSidebar
 
         add.accept( new DynamicImageButton(
             screen, x, y, ICON_WIDTH, ICON_HEIGHT, 29, 1, ICON_TEX_Y_DIFF,
-            TEXTURE, TEX_SIZE, TEX_SIZE, b -> computer.queueEvent( "terminate" ),
+            TEXTURE, TEX_SIZE, TEX_SIZE, b -> input.queueEvent( "terminate" ),
             Arrays.asList(
                 Component.translatable( "gui.computercraft.tooltip.terminate" ),
                 Component.translatable( "gui.computercraft.tooltip.terminate.key" ).withStyle( ChatFormatting.GRAY )
@@ -92,15 +93,15 @@ public final class ComputerSidebar
         );
     }
 
-    private static void toggleComputer( ClientComputer computer )
+    private static void toggleComputer( BooleanSupplier isOn, InputHandler input )
     {
-        if( computer.isOn() )
+        if( isOn.getAsBoolean() )
         {
-            computer.shutdown();
+            input.shutdown();
         }
         else
         {
-            computer.turnOn();
+            input.turnOn();
         }
     }
 }

src/main/java/dan200/computercraft/client/gui/widgets/WidgetTerminal.java

@@ -10,7 +10,7 @@ import com.mojang.blaze3d.vertex.Tesselator;
 import dan200.computercraft.client.render.RenderTypes;
 import dan200.computercraft.client.render.text.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
-import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.shared.computer.core.InputHandler;
 import net.minecraft.SharedConstants;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.components.AbstractWidget;
@@ -30,7 +30,8 @@ public class WidgetTerminal extends AbstractWidget
 {
     private static final float TERMINATE_TIME = 0.5f;
 
-    private final ClientComputer computer;
+    private final @Nonnull Terminal terminal;
+    private final @Nonnull InputHandler computer;
 
     // The positions of the actual terminal
     private final int innerX;
@@ -48,16 +49,17 @@ public class WidgetTerminal extends AbstractWidget
 
     private final BitSet keysDown = new BitSet( 256 );
 
-    public WidgetTerminal( @Nonnull ClientComputer computer, int x, int y, int termWidth, int termHeight )
+    public WidgetTerminal( @Nonnull Terminal terminal, @Nonnull InputHandler computer, int x, int y )
     {
-        super( x, y, termWidth * FONT_WIDTH + MARGIN * 2, termHeight * FONT_HEIGHT + MARGIN * 2, Component.empty() );
+        super( x, y, terminal.getWidth() * FONT_WIDTH + MARGIN * 2, terminal.getHeight() * FONT_HEIGHT + MARGIN * 2, Component.empty() );
 
+        this.terminal = terminal;
         this.computer = computer;
 
         innerX = x + MARGIN;
         innerY = y + MARGIN;
-        innerWidth = termWidth * FONT_WIDTH;
-        innerHeight = termHeight * FONT_HEIGHT;
+        innerWidth = terminal.getWidth() * FONT_WIDTH;
+        innerHeight = terminal.getHeight() * FONT_HEIGHT;
     }
 
     @Override
@@ -170,22 +172,18 @@ public class WidgetTerminal extends AbstractWidget
     public boolean mouseClicked( double mouseX, double mouseY, int button )
     {
         if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( !computer.isColour() || button < 0 || button > 2 ) return false;
+        if( !hasMouseSupport() || button < 0 || button > 2 ) return false;
 
-        Terminal term = computer.getTerminal();
-        if( term != null )
-        {
-            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
+        int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
+        int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
+        charX = Math.min( Math.max( charX, 0 ), terminal.getWidth() - 1 );
+        charY = Math.min( Math.max( charY, 0 ), terminal.getHeight() - 1 );
 
-            computer.mouseClick( button + 1, charX + 1, charY + 1 );
+        computer.mouseClick( button + 1, charX + 1, charY + 1 );
 
-            lastMouseButton = button;
-            lastMouseX = charX;
-            lastMouseY = charY;
-        }
+        lastMouseButton = button;
+        lastMouseX = charX;
+        lastMouseY = charY;
 
         return true;
     }
@@ -194,26 +192,22 @@ public class WidgetTerminal extends AbstractWidget
     public boolean mouseReleased( double mouseX, double mouseY, int button )
     {
         if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( !computer.isColour() || button < 0 || button > 2 ) return false;
+        if( !hasMouseSupport() || button < 0 || button > 2 ) return false;
 
-        Terminal term = computer.getTerminal();
-        if( term != null )
+        int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
+        int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
+        charX = Math.min( Math.max( charX, 0 ), terminal.getWidth() - 1 );
+        charY = Math.min( Math.max( charY, 0 ), terminal.getHeight() - 1 );
+
+        if( lastMouseButton == button )
         {
-            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
-
-            if( lastMouseButton == button )
-            {
-                computer.mouseUp( lastMouseButton + 1, charX + 1, charY + 1 );
-                lastMouseButton = -1;
-            }
-
-            lastMouseX = charX;
-            lastMouseY = charY;
+            computer.mouseUp( lastMouseButton + 1, charX + 1, charY + 1 );
+            lastMouseButton = -1;
         }
 
+        lastMouseX = charX;
+        lastMouseY = charY;
+
         return false;
     }
 
@@ -221,22 +215,18 @@ public class WidgetTerminal extends AbstractWidget
     public boolean mouseDragged( double mouseX, double mouseY, int button, double v2, double v3 )
     {
         if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( !computer.isColour() || button < 0 || button > 2 ) return false;
+        if( !hasMouseSupport() || button < 0 || button > 2 ) return false;
 
-        Terminal term = computer.getTerminal();
-        if( term != null )
+        int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
+        int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
+        charX = Math.min( Math.max( charX, 0 ), terminal.getWidth() - 1 );
+        charY = Math.min( Math.max( charY, 0 ), terminal.getHeight() - 1 );
+
+        if( button == lastMouseButton && (charX != lastMouseX || charY != lastMouseY) )
         {
-            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
-
-            if( button == lastMouseButton && (charX != lastMouseX || charY != lastMouseY) )
-            {
-                computer.mouseDrag( button + 1, charX + 1, charY + 1 );
-                lastMouseX = charX;
-                lastMouseY = charY;
-            }
+            computer.mouseDrag( button + 1, charX + 1, charY + 1 );
+            lastMouseX = charX;
+            lastMouseY = charY;
         }
 
         return false;
@@ -246,21 +236,17 @@ public class WidgetTerminal extends AbstractWidget
     public boolean mouseScrolled( double mouseX, double mouseY, double delta )
     {
         if( !inTermRegion( mouseX, mouseY ) ) return false;
-        if( !computer.isColour() || delta == 0 ) return false;
+        if( !hasMouseSupport() || delta == 0 ) return false;
 
-        Terminal term = computer.getTerminal();
-        if( term != null )
-        {
-            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
-            charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
+        int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
+        int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
+        charX = Math.min( Math.max( charX, 0 ), terminal.getWidth() - 1 );
+        charY = Math.min( Math.max( charY, 0 ), terminal.getHeight() - 1 );
 
-            computer.mouseScroll( delta < 0 ? 1 : -1, charX + 1, charY + 1 );
+        computer.mouseScroll( delta < 0 ? 1 : -1, charX + 1, charY + 1 );
 
-            lastMouseX = charX;
-            lastMouseY = charY;
-        }
+        lastMouseX = charX;
+        lastMouseY = charY;
 
         return true;
     }
@@ -270,6 +256,11 @@ public class WidgetTerminal extends AbstractWidget
         return active && visible && mouseX >= innerX && mouseY >= innerY && mouseX < innerX + innerWidth && mouseY < innerY + innerHeight;
     }
 
+    private boolean hasMouseSupport()
+    {
+        return terminal.isColour();
+    }
+
     public void update()
     {
         if( terminateTimer >= 0 && terminateTimer < TERMINATE_TIME && (terminateTimer += 0.05f) > TERMINATE_TIME )
@@ -315,23 +306,14 @@ public class WidgetTerminal extends AbstractWidget
     public void render( @Nonnull PoseStack transform, int mouseX, int mouseY, float partialTicks )
     {
         if( !visible ) return;
-        Terminal terminal = computer.getTerminal();
 
         var bufferSource = MultiBufferSource.immediate( Tesselator.getInstance().getBuilder() );
         var emitter = FixedWidthFontRenderer.toVertexConsumer( transform, bufferSource.getBuffer( RenderTypes.TERMINAL ) );
 
-        if( terminal != null )
-        {
-            boolean greyscale = !computer.isColour();
-            FixedWidthFontRenderer.drawTerminal(
-                emitter,
-                (float) innerX, (float) innerY, terminal, greyscale, (float) MARGIN, (float) MARGIN, (float) MARGIN, (float) MARGIN
-            );
-        }
-        else
-        {
-            FixedWidthFontRenderer.drawEmptyTerminal( emitter, (float) x, (float) y, (float) width, (float) height );
-        }
+        FixedWidthFontRenderer.drawTerminal(
+            emitter,
+            (float) innerX, (float) innerY, terminal, (float) MARGIN, (float) MARGIN, (float) MARGIN, (float) MARGIN
+        );
 
         bufferSource.endBatch();
     }

src/main/java/dan200/computercraft/client/pocket/ClientPocketComputers.java

@@ -0,0 +1,63 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.pocket;
+
+import dan200.computercraft.shared.computer.core.ComputerFamily;
+import dan200.computercraft.shared.computer.core.ServerComputer;
+import dan200.computercraft.shared.computer.items.ItemComputer;
+import dan200.computercraft.shared.network.client.PocketComputerDataMessage;
+import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import net.minecraft.world.item.ItemStack;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Maps {@link ServerComputer#getInstanceID()} to locals {@link PocketComputerData}.
+ * <p>
+ * This is populated by {@link PocketComputerDataMessage} and accessed when rendering pocket computers
+ */
+public final class ClientPocketComputers
+{
+    private static final Int2ObjectMap<PocketComputerData> instances = new Int2ObjectOpenHashMap<>();
+
+    private ClientPocketComputers()
+    {
+    }
+
+    public static void reset()
+    {
+        instances.clear();
+    }
+
+    public static void remove( int id )
+    {
+        instances.remove( id );
+    }
+
+    /**
+     * Get or create a pocket computer.
+     *
+     * @param instanceId The instance ID of the pocket computer.
+     * @param advanced   Whether this computer has an advanced terminal.
+     * @return The pocket computer data.
+     */
+    @Nonnull
+    public static PocketComputerData get( int instanceId, boolean advanced )
+    {
+        PocketComputerData computer = instances.get( instanceId );
+        if( computer == null ) instances.put( instanceId, computer = new PocketComputerData( advanced ) );
+        return computer;
+    }
+
+    @Nonnull
+    public static PocketComputerData get( ItemStack stack )
+    {
+        ComputerFamily family = stack.getItem() instanceof ItemComputer computer ? computer.getFamily() : ComputerFamily.NORMAL;
+        return get( ItemPocketComputer.getInstanceID( stack ), family != ComputerFamily.NORMAL );
+    }
+}

src/main/java/dan200/computercraft/client/pocket/PocketComputerData.java

@@ -0,0 +1,63 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.pocket;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.core.terminal.Terminal;
+import dan200.computercraft.shared.computer.core.ComputerState;
+import dan200.computercraft.shared.network.client.TerminalState;
+import dan200.computercraft.shared.pocket.core.PocketServerComputer;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Clientside data about a pocket computer.
+ * <p>
+ * Normal computers don't store any state long-term on the client - everything is tied to the container and only synced
+ * while the UI is open. Pocket computers are a little more complex, as their on/off state is visible on the item's
+ * texture, and the terminal can be viewed at any time. This class is what holds this needed data clientside.
+ *
+ * @see ClientPocketComputers The registry which holds pocket computers.
+ * @see PocketServerComputer The server-side pocket computer.
+ */
+public class PocketComputerData
+{
+    private final Terminal terminal;
+    private ComputerState state = ComputerState.OFF;
+    private int lightColour = -1;
+
+    public PocketComputerData( boolean colour )
+    {
+        terminal = new Terminal( ComputerCraft.pocketTermWidth, ComputerCraft.pocketTermHeight, colour );
+    }
+
+    public int getLightState()
+    {
+        return state != ComputerState.OFF ? lightColour : -1;
+    }
+
+    @Nonnull
+    public Terminal getTerminal()
+    {
+        return terminal;
+    }
+
+    public ComputerState getState()
+    {
+        return state;
+    }
+
+    public void setState( ComputerState state, int lightColour )
+    {
+        this.state = state;
+        this.lightColour = lightColour;
+    }
+
+    public void setTerminal( TerminalState state )
+    {
+        state.apply( terminal );
+    }
+}

src/main/java/dan200/computercraft/client/render/ItemPocketRenderer.java

@@ -10,9 +10,10 @@ import com.mojang.blaze3d.vertex.VertexConsumer;
 import com.mojang.math.Matrix4f;
 import com.mojang.math.Vector3f;
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.pocket.ClientPocketComputers;
+import dan200.computercraft.client.pocket.PocketComputerData;
 import dan200.computercraft.client.render.text.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
-import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
@@ -56,20 +57,11 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
     @Override
     protected void renderItem( PoseStack transform, MultiBufferSource bufferSource, ItemStack stack, int light )
     {
-        ClientComputer computer = ItemPocketComputer.createClientComputer( stack );
-        Terminal terminal = computer == null ? null : computer.getTerminal();
+        PocketComputerData computer = ClientPocketComputers.get( stack );
+        Terminal terminal = computer.getTerminal();
 
-        int termWidth, termHeight;
-        if( terminal == null )
-        {
-            termWidth = ComputerCraft.pocketTermWidth;
-            termHeight = ComputerCraft.pocketTermHeight;
-        }
-        else
-        {
-            termWidth = terminal.getWidth();
-            termHeight = terminal.getHeight();
-        }
+        int termWidth = terminal.getWidth();
+        int termHeight = terminal.getHeight();
 
         int width = termWidth * FONT_WIDTH + MARGIN * 2;
         int height = termHeight * FONT_HEIGHT + MARGIN * 2;
@@ -94,24 +86,14 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
         renderFrame( matrix, bufferSource, family, frameColour, light, width, height );
 
         // Render the light
-        int lightColour = ItemPocketComputer.getLightState( stack );
+        int lightColour = ClientPocketComputers.get( stack ).getLightState();
         if( lightColour == -1 ) lightColour = Colour.BLACK.getHex();
         renderLight( transform, bufferSource, lightColour, width, height );
 
-        if( computer != null && terminal != null )
-        {
-            FixedWidthFontRenderer.drawTerminal(
-                FixedWidthFontRenderer.toVertexConsumer( transform, bufferSource.getBuffer( RenderTypes.TERMINAL ) ),
-                MARGIN, MARGIN, terminal, !computer.isColour(), MARGIN, MARGIN, MARGIN, MARGIN
-            );
-        }
-        else
-        {
-            FixedWidthFontRenderer.drawEmptyTerminal(
-                FixedWidthFontRenderer.toVertexConsumer( transform, bufferSource.getBuffer( RenderTypes.TERMINAL ) ),
-                0, 0, width, height
-            );
-        }
+        FixedWidthFontRenderer.drawTerminal(
+            FixedWidthFontRenderer.toVertexConsumer( transform, bufferSource.getBuffer( RenderTypes.TERMINAL ) ),
+            MARGIN, MARGIN, terminal, MARGIN, MARGIN, MARGIN, MARGIN
+        );
 
         transform.popPose();
     }

src/main/java/dan200/computercraft/client/render/MonitorTextureBufferShader.java

@@ -98,7 +98,7 @@ public class MonitorTextureBufferShader extends ShaderInstance
         buffer.limit( pos );
     }
 
-    public static void setUniformData( ByteBuffer buffer, Terminal terminal, boolean greyscale )
+    public static void setUniformData( ByteBuffer buffer, Terminal terminal )
     {
         int pos = 0;
         var palette = terminal.getPalette();
@@ -106,7 +106,7 @@ public class MonitorTextureBufferShader extends ShaderInstance
         {
             {
                 double[] colour = palette.getColour( i );
-                if( greyscale )
+                if( !terminal.isColour() )
                 {
                     float f = FixedWidthFontRenderer.toGreyscale( colour );
                     buffer.putFloat( pos, f ).putFloat( pos + 4, f ).putFloat( pos + 8, f );

src/main/java/dan200/computercraft/client/render/PrintoutRenderer.java

@@ -63,7 +63,7 @@ public final class PrintoutRenderer
         {
             FixedWidthFontRenderer.drawString( emitter,
                 x, y + line * FONT_HEIGHT, text[start + line], colours[start + line],
-                Palette.DEFAULT, false, light
+                Palette.DEFAULT, light
             );
         }
     }
@@ -77,7 +77,7 @@ public final class PrintoutRenderer
             FixedWidthFontRenderer.drawString( emitter,
                 x, y + line * FONT_HEIGHT,
                 new TextBuffer( text[start + line] ), new TextBuffer( colours[start + line] ),
-                Palette.DEFAULT, false, light
+                Palette.DEFAULT, light
             );
         }
     }

src/main/java/dan200/computercraft/client/render/TileEntityMonitorRenderer.java

@@ -156,7 +156,7 @@ public class TileEntityMonitorRenderer implements BlockEntityRenderer<TileMonito
                     DirectBuffers.setBufferData( GL31.GL_TEXTURE_BUFFER, monitor.tboBuffer, terminalBuffer, GL20.GL_STATIC_DRAW );
 
                     var uniformBuffer = getBuffer( MonitorTextureBufferShader.UNIFORM_SIZE );
-                    MonitorTextureBufferShader.setUniformData( uniformBuffer, terminal, !monitor.isColour() );
+                    MonitorTextureBufferShader.setUniformData( uniformBuffer, terminal );
                     DirectBuffers.setBufferData( GL31.GL_UNIFORM_BUFFER, monitor.tboUniform, uniformBuffer, GL20.GL_STATIC_DRAW );
                 }
 
@@ -192,13 +192,13 @@ public class TileEntityMonitorRenderer implements BlockEntityRenderer<TileMonito
                     // and starting and ending offset, and so need to use two buffers instead.
 
                     renderToBuffer( backgroundBuffer, size, sink ->
-                        DirectFixedWidthFontRenderer.drawTerminalBackground( sink, 0, 0, terminal, !monitor.isColour(), yMargin, yMargin, xMargin, xMargin ) );
+                        DirectFixedWidthFontRenderer.drawTerminalBackground( sink, 0, 0, terminal, yMargin, yMargin, xMargin, xMargin ) );
 
                     renderToBuffer( foregroundBuffer, size, sink -> {
-                        DirectFixedWidthFontRenderer.drawTerminalForeground( sink, 0, 0, terminal, !monitor.isColour() );
+                        DirectFixedWidthFontRenderer.drawTerminalForeground( sink, 0, 0, terminal );
                         // If the cursor is visible, we append it to the end of our buffer. When rendering, we can either
                         // render n or n+1 quads and so toggle the cursor on and off.
-                        DirectFixedWidthFontRenderer.drawCursor( sink, 0, 0, terminal, !monitor.isColour() );
+                        DirectFixedWidthFontRenderer.drawCursor( sink, 0, 0, terminal );
                     } );
                 }
 

src/main/java/dan200/computercraft/client/render/TileEntityTurtleRenderer.java

@@ -9,6 +9,7 @@ import com.mojang.blaze3d.vertex.PoseStack;
 import com.mojang.blaze3d.vertex.VertexConsumer;
 import com.mojang.math.Matrix4f;
 import com.mojang.math.Vector3f;
+import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
@@ -44,8 +45,8 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
 {
     private static final ModelResourceLocation NORMAL_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_normal", "inventory" );
     private static final ModelResourceLocation ADVANCED_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_advanced", "inventory" );
-    private static final ModelResourceLocation COLOUR_TURTLE_MODEL = new ModelResourceLocation( "computercraft:turtle_colour", "inventory" );
-    private static final ModelResourceLocation ELF_OVERLAY_MODEL = new ModelResourceLocation( "computercraft:turtle_elf_overlay", "inventory" );
+    private static final ResourceLocation COLOUR_TURTLE_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_colour" );
+    private static final ResourceLocation ELF_OVERLAY_MODEL = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_elf_overlay" );
 
     private final RandomSource random = RandomSource.create( 0 );
 
@@ -56,7 +57,7 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
         renderer = context.getBlockEntityRenderDispatcher();
     }
 
-    public static ModelResourceLocation getTurtleModel( ComputerFamily family, boolean coloured )
+    public static ResourceLocation getTurtleModel( ComputerFamily family, boolean coloured )
     {
         switch( family )
         {
@@ -68,9 +69,9 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
         }
     }
 
-    public static ModelResourceLocation getTurtleOverlayModel( ResourceLocation overlay, boolean christmas )
+    public static ResourceLocation getTurtleOverlayModel( ResourceLocation overlay, boolean christmas )
     {
-        if( overlay != null ) return new ModelResourceLocation( overlay, "inventory" );
+        if( overlay != null ) return overlay;
         if( christmas ) return ELF_OVERLAY_MODEL;
         return null;
     }
@@ -125,7 +126,7 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
         renderModel( transform, buffer, lightmapCoord, overlayLight, getTurtleModel( family, colour != -1 ), colour == -1 ? null : new int[] { colour } );
 
         // Render the overlay
-        ModelResourceLocation overlayModel = getTurtleOverlayModel( overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS );
+        ResourceLocation overlayModel = getTurtleOverlayModel( overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS );
         if( overlayModel != null )
         {
             renderModel( transform, buffer, lightmapCoord, overlayLight, overlayModel, null );
@@ -157,7 +158,7 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
         transform.popPose();
     }
 
-    private void renderModel( @Nonnull PoseStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, ModelResourceLocation modelLocation, int[] tints )
+    private void renderModel( @Nonnull PoseStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, ResourceLocation modelLocation, int[] tints )
     {
         ModelManager modelManager = Minecraft.getInstance().getItemRenderer().getItemModelShaper().getModelManager();
         renderModel( transform, renderer, lightmapCoord, overlayLight, modelManager.getModel( modelLocation ), tints );

src/main/java/dan200/computercraft/client/render/TurtleSmartItemModel.java

@@ -17,7 +17,6 @@ import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.block.model.ItemTransforms;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.client.resources.model.ModelManager;
-import net.minecraft.client.resources.model.ModelResourceLocation;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.item.ItemStack;
 import net.minecraftforge.client.model.BakedModelWrapper;
@@ -100,7 +99,7 @@ public class TurtleSmartItemModel extends BakedModelWrapper<BakedModel>
         ArrayList<BakedModel> parts = new ArrayList<>( 4 );
         parts.add( new TransformedBakedModel( combo.colour() ? colourModel : familyModel, transformation ) );
 
-        ModelResourceLocation overlayModelLocation = TileEntityTurtleRenderer.getTurtleOverlayModel( combo.overlay(), combo.christmas() );
+        ResourceLocation overlayModelLocation = TileEntityTurtleRenderer.getTurtleOverlayModel( combo.overlay(), combo.christmas() );
         if( overlayModelLocation != null )
         {
             parts.add( new TransformedBakedModel( modelManager.getModel( overlayModelLocation ), transformation ) );

src/main/java/dan200/computercraft/client/render/text/DirectFixedWidthFontRenderer.java

@@ -25,14 +25,14 @@ import static org.lwjgl.system.MemoryUtil.*;
 /**
  * An optimised copy of {@link FixedWidthFontRenderer} emitter emits directly to a {@link QuadEmitter} rather than
  * emitting to {@link VertexConsumer}. This allows us to emit vertices very quickly, when using the VBO renderer.
- *
+ * <p>
  * There are some limitations here:
  * <ul>
  *   <li>No transformation matrix (not needed for VBOs).</li>
  *   <li>Only works with {@link DefaultVertexFormat#POSITION_COLOR_TEX_LIGHTMAP}.</li>
  *   <li>The buffer <strong>MUST</strong> be allocated with {@link MemoryTracker}, and not through any other means.</li>
  * </ul>
- *
+ * <p>
  * Note this is almost an exact copy of {@link FixedWidthFontRenderer}. While the code duplication is unfortunate,
  * it is measurably faster than introducing polymorphism into {@link FixedWidthFontRenderer}.
  *
@@ -62,25 +62,25 @@ public final class DirectFixedWidthFontRenderer
         );
     }
 
-    private static void drawQuad( QuadEmitter emitter, float x, float y, float width, float height, Palette palette, boolean greyscale, char colourIndex )
+    private static void drawQuad( QuadEmitter emitter, float x, float y, float width, float height, Palette palette, char colourIndex )
     {
-        byte[] colour = palette.getByteColour( getColour( colourIndex, Colour.BLACK ), greyscale );
+        byte[] colour = palette.getRenderColours( getColour( colourIndex, Colour.BLACK ) );
         quad( emitter, x, y, x + width, y + height, 0f, colour, BACKGROUND_START, BACKGROUND_START, BACKGROUND_END, BACKGROUND_END );
     }
 
     private static void drawBackground(
-        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer backgroundColour, @Nonnull Palette palette, boolean greyscale,
+        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer backgroundColour, @Nonnull Palette palette,
         float leftMarginSize, float rightMarginSize, float height
     )
     {
         if( leftMarginSize > 0 )
         {
-            drawQuad( emitter, x - leftMarginSize, y, leftMarginSize, height, palette, greyscale, backgroundColour.charAt( 0 ) );
+            drawQuad( emitter, x - leftMarginSize, y, leftMarginSize, height, palette, backgroundColour.charAt( 0 ) );
         }
 
         if( rightMarginSize > 0 )
         {
-            drawQuad( emitter, x + backgroundColour.length() * FONT_WIDTH, y, rightMarginSize, height, palette, greyscale, backgroundColour.charAt( backgroundColour.length() - 1 ) );
+            drawQuad( emitter, x + backgroundColour.length() * FONT_WIDTH, y, rightMarginSize, height, palette, backgroundColour.charAt( backgroundColour.length() - 1 ) );
         }
 
         // Batch together runs of identical background cells.
@@ -93,7 +93,7 @@ public final class DirectFixedWidthFontRenderer
 
             if( blockColour != '\0' )
             {
-                drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, greyscale, blockColour );
+                drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, blockColour );
             }
 
             blockColour = colourIndex;
@@ -102,15 +102,15 @@ public final class DirectFixedWidthFontRenderer
 
         if( blockColour != '\0' )
         {
-            drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (backgroundColour.length() - blockStart), height, palette, greyscale, blockColour );
+            drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (backgroundColour.length() - blockStart), height, palette, blockColour );
         }
     }
 
-    public static void drawString( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer text, @Nonnull TextBuffer textColour, @Nonnull Palette palette, boolean greyscale )
+    public static void drawString( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer text, @Nonnull TextBuffer textColour, @Nonnull Palette palette )
     {
         for( int i = 0; i < text.length(); i++ )
         {
-            byte[] colour = palette.getByteColour( getColour( textColour.charAt( i ), Colour.BLACK ), greyscale );
+            byte[] colour = palette.getRenderColours( getColour( textColour.charAt( i ), Colour.BLACK ) );
 
             int index = text.charAt( i );
             if( index > 255 ) index = '?';
@@ -119,7 +119,7 @@ public final class DirectFixedWidthFontRenderer
 
     }
 
-    public static void drawTerminalForeground( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal, boolean greyscale )
+    public static void drawTerminalForeground( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal )
     {
         Palette palette = terminal.getPalette();
         int height = terminal.getHeight();
@@ -130,13 +130,13 @@ public final class DirectFixedWidthFontRenderer
             float rowY = y + FONT_HEIGHT * i;
             drawString(
                 emitter, x, rowY, terminal.getLine( i ), terminal.getTextColourLine( i ),
-                palette, greyscale
+                palette
             );
         }
     }
 
     public static void drawTerminalBackground(
-        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal, boolean greyscale,
+        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal,
         float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
     )
     {
@@ -145,12 +145,12 @@ public final class DirectFixedWidthFontRenderer
 
         // Top and bottom margins
         drawBackground(
-            emitter, x, y - topMarginSize, terminal.getBackgroundColourLine( 0 ), palette, greyscale,
+            emitter, x, y - topMarginSize, terminal.getBackgroundColourLine( 0 ), palette,
             leftMarginSize, rightMarginSize, topMarginSize
         );
 
         drawBackground(
-            emitter, x, y + height * FONT_HEIGHT, terminal.getBackgroundColourLine( height - 1 ), palette, greyscale,
+            emitter, x, y + height * FONT_HEIGHT, terminal.getBackgroundColourLine( height - 1 ), palette,
             leftMarginSize, rightMarginSize, bottomMarginSize
         );
 
@@ -159,17 +159,17 @@ public final class DirectFixedWidthFontRenderer
         {
             float rowY = y + FONT_HEIGHT * i;
             drawBackground(
-                emitter, x, rowY, terminal.getBackgroundColourLine( i ), palette, greyscale,
+                emitter, x, rowY, terminal.getBackgroundColourLine( i ), palette,
                 leftMarginSize, rightMarginSize, FONT_HEIGHT
             );
         }
     }
 
-    public static void drawCursor( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal, boolean greyscale )
+    public static void drawCursor( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal )
     {
         if( isCursorVisible( terminal ) )
         {
-            byte[] colour = terminal.getPalette().getByteColour( 15 - terminal.getTextColour(), greyscale );
+            byte[] colour = terminal.getPalette().getRenderColours( 15 - terminal.getTextColour() );
             drawChar( emitter, x + terminal.getCursorX() * FONT_WIDTH, y + terminal.getCursorY() * FONT_HEIGHT, '_', colour );
         }
     }

src/main/java/dan200/computercraft/client/render/text/FixedWidthFontRenderer.java

@@ -22,7 +22,7 @@ import static dan200.computercraft.client.render.RenderTypes.FULL_BRIGHT_LIGHTMA
 
 /**
  * Handles rendering fixed width text and computer terminals.
- *
+ * <p>
  * This class has several modes of usage:
  * <ul>
  * <li>{@link #drawString}: Drawing basic text without a terminal (such as for printouts). Unlike the other methods,
@@ -89,25 +89,25 @@ public final class FixedWidthFontRenderer
         quad( emitter, x, y, x + width, y + height, z, colour, BACKGROUND_START, BACKGROUND_START, BACKGROUND_END, BACKGROUND_END, light );
     }
 
-    private static void drawQuad( QuadEmitter emitter, float x, float y, float width, float height, Palette palette, boolean greyscale, char colourIndex, int light )
+    private static void drawQuad( QuadEmitter emitter, float x, float y, float width, float height, Palette palette, char colourIndex, int light )
     {
-        byte[] colour = palette.getByteColour( getColour( colourIndex, Colour.BLACK ), greyscale );
+        byte[] colour = palette.getRenderColours( getColour( colourIndex, Colour.BLACK ) );
         drawQuad( emitter, x, y, 0, width, height, colour, light );
     }
 
     private static void drawBackground(
-        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer backgroundColour, @Nonnull Palette palette, boolean greyscale,
+        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer backgroundColour, @Nonnull Palette palette,
         float leftMarginSize, float rightMarginSize, float height, int light
     )
     {
         if( leftMarginSize > 0 )
         {
-            drawQuad( emitter, x - leftMarginSize, y, leftMarginSize, height, palette, greyscale, backgroundColour.charAt( 0 ), light );
+            drawQuad( emitter, x - leftMarginSize, y, leftMarginSize, height, palette, backgroundColour.charAt( 0 ), light );
         }
 
         if( rightMarginSize > 0 )
         {
-            drawQuad( emitter, x + backgroundColour.length() * FONT_WIDTH, y, rightMarginSize, height, palette, greyscale, backgroundColour.charAt( backgroundColour.length() - 1 ), light );
+            drawQuad( emitter, x + backgroundColour.length() * FONT_WIDTH, y, rightMarginSize, height, palette, backgroundColour.charAt( backgroundColour.length() - 1 ), light );
         }
 
         // Batch together runs of identical background cells.
@@ -120,7 +120,7 @@ public final class FixedWidthFontRenderer
 
             if( blockColour != '\0' )
             {
-                drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, greyscale, blockColour, light );
+                drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (i - blockStart), height, palette, blockColour, light );
             }
 
             blockColour = colourIndex;
@@ -129,15 +129,15 @@ public final class FixedWidthFontRenderer
 
         if( blockColour != '\0' )
         {
-            drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (backgroundColour.length() - blockStart), height, palette, greyscale, blockColour, light );
+            drawQuad( emitter, x + blockStart * FONT_WIDTH, y, FONT_WIDTH * (backgroundColour.length() - blockStart), height, palette, blockColour, light );
         }
     }
 
-    public static void drawString( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer text, @Nonnull TextBuffer textColour, @Nonnull Palette palette, boolean greyscale, int light )
+    public static void drawString( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull TextBuffer text, @Nonnull TextBuffer textColour, @Nonnull Palette palette, int light )
     {
         for( int i = 0; i < text.length(); i++ )
         {
-            byte[] colour = palette.getByteColour( getColour( textColour.charAt( i ), Colour.BLACK ), greyscale );
+            byte[] colour = palette.getRenderColours( getColour( textColour.charAt( i ), Colour.BLACK ) );
 
             int index = text.charAt( i );
             if( index > 255 ) index = '?';
@@ -146,7 +146,7 @@ public final class FixedWidthFontRenderer
 
     }
 
-    public static void drawTerminalForeground( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal, boolean greyscale )
+    public static void drawTerminalForeground( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal )
     {
         Palette palette = terminal.getPalette();
         int height = terminal.getHeight();
@@ -157,13 +157,13 @@ public final class FixedWidthFontRenderer
             float rowY = y + FONT_HEIGHT * i;
             drawString(
                 emitter, x, rowY, terminal.getLine( i ), terminal.getTextColourLine( i ),
-                palette, greyscale, FULL_BRIGHT_LIGHTMAP
+                palette, FULL_BRIGHT_LIGHTMAP
             );
         }
     }
 
     public static void drawTerminalBackground(
-        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal, boolean greyscale,
+        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal,
         float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
     )
     {
@@ -172,12 +172,12 @@ public final class FixedWidthFontRenderer
 
         // Top and bottom margins
         drawBackground(
-            emitter, x, y - topMarginSize, terminal.getBackgroundColourLine( 0 ), palette, greyscale,
+            emitter, x, y - topMarginSize, terminal.getBackgroundColourLine( 0 ), palette,
             leftMarginSize, rightMarginSize, topMarginSize, FULL_BRIGHT_LIGHTMAP
         );
 
         drawBackground(
-            emitter, x, y + height * FONT_HEIGHT, terminal.getBackgroundColourLine( height - 1 ), palette, greyscale,
+            emitter, x, y + height * FONT_HEIGHT, terminal.getBackgroundColourLine( height - 1 ), palette,
             leftMarginSize, rightMarginSize, bottomMarginSize, FULL_BRIGHT_LIGHTMAP
         );
 
@@ -186,7 +186,7 @@ public final class FixedWidthFontRenderer
         {
             float rowY = y + FONT_HEIGHT * i;
             drawBackground(
-                emitter, x, rowY, terminal.getBackgroundColourLine( i ), palette, greyscale,
+                emitter, x, rowY, terminal.getBackgroundColourLine( i ), palette,
                 leftMarginSize, rightMarginSize, FONT_HEIGHT, FULL_BRIGHT_LIGHTMAP
             );
         }
@@ -201,23 +201,22 @@ public final class FixedWidthFontRenderer
         return cursorX >= 0 && cursorX < terminal.getWidth() && cursorY >= 0 && cursorY < terminal.getHeight();
     }
 
-    public static void drawCursor( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal, boolean greyscale )
+    public static void drawCursor( @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal )
     {
         if( isCursorVisible( terminal ) && FrameInfo.getGlobalCursorBlink() )
         {
-            byte[] colour = terminal.getPalette().getByteColour( 15 - terminal.getTextColour(), greyscale );
+            byte[] colour = terminal.getPalette().getRenderColours( 15 - terminal.getTextColour() );
             drawChar( emitter, x + terminal.getCursorX() * FONT_WIDTH, y + terminal.getCursorY() * FONT_HEIGHT, '_', colour, FULL_BRIGHT_LIGHTMAP );
         }
     }
 
     public static void drawTerminal(
-        @Nonnull QuadEmitter emitter, float x, float y,
-        @Nonnull Terminal terminal, boolean greyscale,
+        @Nonnull QuadEmitter emitter, float x, float y, @Nonnull Terminal terminal,
         float topMarginSize, float bottomMarginSize, float leftMarginSize, float rightMarginSize
     )
     {
         drawTerminalBackground(
-            emitter, x, y, terminal, greyscale,
+            emitter, x, y, terminal,
             topMarginSize, bottomMarginSize, leftMarginSize, rightMarginSize
         );
 
@@ -227,8 +226,8 @@ public final class FixedWidthFontRenderer
         var transformBackup = emitter.poseMatrix().copy();
         emitter.poseMatrix().translate( new Vector3f( 0, 0, Z_OFFSET ) );
 
-        drawTerminalForeground( emitter, x, y, terminal, greyscale );
-        drawCursor( emitter, x, y, terminal, greyscale );
+        drawTerminalForeground( emitter, x, y, terminal );
+        drawCursor( emitter, x, y, terminal );
 
         emitter.poseMatrix().load( transformBackup );
     }

src/main/java/dan200/computercraft/client/turtle/TurtleModemModeller.java

@@ -5,39 +5,40 @@
  */
 package dan200.computercraft.client.turtle;
 
+import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.client.turtle.TurtleUpgradeModeller;
 import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.shared.turtle.upgrades.TurtleModem;
-import net.minecraft.client.resources.model.ModelResourceLocation;
 import net.minecraft.nbt.CompoundTag;
+import net.minecraft.resources.ResourceLocation;
 import org.jetbrains.annotations.Nullable;
 
 import javax.annotation.Nonnull;
 
 public class TurtleModemModeller implements TurtleUpgradeModeller<TurtleModem>
 {
-    private final ModelResourceLocation leftOffModel;
-    private final ModelResourceLocation rightOffModel;
-    private final ModelResourceLocation leftOnModel;
-    private final ModelResourceLocation rightOnModel;
+    private final ResourceLocation leftOffModel;
+    private final ResourceLocation rightOffModel;
+    private final ResourceLocation leftOnModel;
+    private final ResourceLocation rightOnModel;
 
     public TurtleModemModeller( boolean advanced )
     {
         if( advanced )
         {
-            leftOffModel = new ModelResourceLocation( "computercraft:turtle_modem_advanced_off_left", "inventory" );
-            rightOffModel = new ModelResourceLocation( "computercraft:turtle_modem_advanced_off_right", "inventory" );
-            leftOnModel = new ModelResourceLocation( "computercraft:turtle_modem_advanced_on_left", "inventory" );
-            rightOnModel = new ModelResourceLocation( "computercraft:turtle_modem_advanced_on_right", "inventory" );
+            leftOffModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_advanced_off_left" );
+            rightOffModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_advanced_off_right" );
+            leftOnModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_advanced_on_left" );
+            rightOnModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_advanced_on_right" );
         }
         else
         {
-            leftOffModel = new ModelResourceLocation( "computercraft:turtle_modem_normal_off_left", "inventory" );
-            rightOffModel = new ModelResourceLocation( "computercraft:turtle_modem_normal_off_right", "inventory" );
-            leftOnModel = new ModelResourceLocation( "computercraft:turtle_modem_normal_on_left", "inventory" );
-            rightOnModel = new ModelResourceLocation( "computercraft:turtle_modem_normal_on_right", "inventory" );
+            leftOffModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_normal_off_left" );
+            rightOffModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_normal_off_right" );
+            leftOnModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_normal_on_left" );
+            rightOnModel = new ResourceLocation( ComputerCraft.MOD_ID, "block/turtle_modem_normal_on_right" );
         }
     }
 

src/main/java/dan200/computercraft/client/util/DirectBuffers.java

@@ -37,7 +37,7 @@ public class DirectBuffers
 
     /**
      * Delete a previously created buffer.
-     *
+     * <p>
      * On Linux, {@link GlStateManager#_glDeleteBuffers(int)} clears a buffer before deleting it. However, this involves
      * binding and unbinding the buffer, conflicting with {@link BufferUploader}'s cache. This deletion method uses
      * our existing {@link #setEmptyBufferData(int, int, int)}, which correctly handles clearing the buffer.

src/main/java/dan200/computercraft/client/util/DirectVertexBuffer.java

@@ -19,7 +19,7 @@ import java.nio.ByteBuffer;
 
 /**
  * A version of {@link VertexBuffer} which allows uploading {@link ByteBuffer}s directly.
- *
+ * <p>
  * This should probably be its own class (rather than subclassing), but I need access to {@link VertexBuffer#drawWithShader}.
  */
 public class DirectVertexBuffer extends VertexBuffer

src/main/java/dan200/computercraft/core/ComputerContext.java

@@ -0,0 +1,120 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.core;
+
+import dan200.computercraft.core.computer.ComputerThread;
+import dan200.computercraft.core.computer.GlobalEnvironment;
+import dan200.computercraft.core.computer.mainthread.MainThreadScheduler;
+import dan200.computercraft.core.lua.CobaltLuaMachine;
+import dan200.computercraft.core.lua.ILuaMachine;
+
+import javax.annotation.CheckReturnValue;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * The global context under which computers run.
+ */
+public final class ComputerContext
+{
+    private final GlobalEnvironment globalEnvironment;
+    private final ComputerThread computerScheduler;
+    private final MainThreadScheduler mainThreadScheduler;
+    private final ILuaMachine.Factory factory;
+
+    public ComputerContext(
+        GlobalEnvironment globalEnvironment, ComputerThread computerScheduler,
+        MainThreadScheduler mainThreadScheduler, ILuaMachine.Factory factory
+    )
+    {
+        this.globalEnvironment = globalEnvironment;
+        this.computerScheduler = computerScheduler;
+        this.mainThreadScheduler = mainThreadScheduler;
+        this.factory = factory;
+    }
+
+    /**
+     * Create a default {@link ComputerContext} with the given global environment.
+     *
+     * @param environment         The current global environment.
+     * @param threads             The number of threads to use for the {@link #computerScheduler()}
+     * @param mainThreadScheduler The main thread scheduler to use.
+     */
+    public ComputerContext( GlobalEnvironment environment, int threads, MainThreadScheduler mainThreadScheduler )
+    {
+        this( environment, new ComputerThread( threads ), mainThreadScheduler, CobaltLuaMachine::new );
+    }
+
+    /**
+     * The global environment.
+     *
+     * @return The current global environment.
+     */
+    public GlobalEnvironment globalEnvironment()
+    {
+        return globalEnvironment;
+    }
+
+    /**
+     * The {@link ComputerThread} instance under which computers are run. This is closed when the context is closed, and
+     * so should be unique per-context.
+     *
+     * @return The current computer thread manager.
+     */
+    public ComputerThread computerScheduler()
+    {
+        return computerScheduler;
+    }
+
+    /**
+     * The {@link MainThreadScheduler} instance used to run main-thread tasks.
+     *
+     * @return The current main thread scheduler.
+     */
+    public MainThreadScheduler mainThreadScheduler()
+    {
+        return mainThreadScheduler;
+    }
+
+    /**
+     * The factory to create new Lua machines.
+     *
+     * @return The current Lua machine factory.
+     */
+    public ILuaMachine.Factory luaFactory()
+    {
+        return factory;
+    }
+
+    /**
+     * Close the current {@link ComputerContext}, disposing of any resources inside.
+     *
+     * @param timeout The maximum time to wait.
+     * @param unit    The unit {@code timeout} is in.
+     * @return Whether the context was successfully shut down.
+     * @throws InterruptedException If interrupted while waiting.
+     */
+    @CheckReturnValue
+    public boolean close( long timeout, TimeUnit unit ) throws InterruptedException
+    {
+        return computerScheduler().stop( timeout, unit );
+    }
+
+    /**
+     * Close the current {@link ComputerContext}, disposing of any resources inside.
+     *
+     * @param timeout The maximum time to wait.
+     * @param unit    The unit {@code timeout} is in.
+     * @throws IllegalStateException If the computer thread was not shut down in time.
+     * @throws InterruptedException  If interrupted while waiting.
+     */
+    public void ensureClosed( long timeout, TimeUnit unit ) throws InterruptedException
+    {
+        if( !computerScheduler().stop( timeout, unit ) )
+        {
+            throw new IllegalStateException( "Failed to shutdown ComputerContext in time." );
+        }
+    }
+}

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

@@ -16,7 +16,7 @@ import dan200.computercraft.core.apis.handles.EncodedWritableHandle;
 import dan200.computercraft.core.filesystem.FileSystem;
 import dan200.computercraft.core.filesystem.FileSystemException;
 import dan200.computercraft.core.filesystem.FileSystemWrapper;
-import dan200.computercraft.core.tracking.TrackingField;
+import dan200.computercraft.core.metrics.Metrics;
 
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
@@ -43,20 +43,20 @@ import java.util.function.Function;
  * <li>**File and directory manipulation:** For instance, moving or copying files. See {@link #makeDir}, {@link #move},
  * {@link #copy} and {@link #delete}.</li>
  * </ul>
- *
+ * <p>
  * :::note
  * All functions in the API work on absolute paths, and do not take the @{shell.dir|current directory} into account.
  * You can use @{shell.resolve} to convert a relative path into an absolute one.
  * :::
- *
+ * <p>
  * ## Mounts
  * While a computer can only have one hard drive and filesystem, other filesystems may be "mounted" inside it. For
  * instance, the {@link dan200.computercraft.shared.peripheral.diskdrive.DiskDrivePeripheral drive peripheral} mounts
  * its disk's contents at {@code "disk/"}, {@code "disk1/"}, etc...
- *
+ * <p>
  * You can see which mount a path belongs to with the {@link #getDrive} function. This returns {@code "hdd"} for the
  * computer's main filesystem ({@code "/"}), {@code "rom"} for the rom ({@code "rom/"}).
- *
+ * <p>
  * Most filesystems have a limited capacity, operations which would cause that capacity to be reached (such as writing
  * an incredibly large file) will fail. You can see a mount's capacity with {@link #getCapacity} and the remaining
  * space with {@link #getFreeSpace}.
@@ -108,7 +108,7 @@ public class FSAPI implements ILuaAPI
     @LuaFunction
     public final String[] list( String path ) throws LuaException
     {
-        environment.addTrackingChange( TrackingField.FS_OPS );
+        environment.observe( Metrics.FS_OPS );
         try
         {
             return fileSystem.list( path );
@@ -276,7 +276,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            environment.addTrackingChange( TrackingField.FS_OPS );
+            environment.observe( Metrics.FS_OPS );
             fileSystem.makeDir( path );
         }
         catch( FileSystemException e )
@@ -287,7 +287,7 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Moves a file or directory from one path to another.
-     *
+     * <p>
      * Any parent directories are created as needed.
      *
      * @param path The current file or directory to move from.
@@ -299,7 +299,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            environment.addTrackingChange( TrackingField.FS_OPS );
+            environment.observe( Metrics.FS_OPS );
             fileSystem.move( path, dest );
         }
         catch( FileSystemException e )
@@ -310,7 +310,7 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Copies a file or directory to a new path.
-     *
+     * <p>
      * Any parent directories are created as needed.
      *
      * @param path The file or directory to copy.
@@ -322,7 +322,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            environment.addTrackingChange( TrackingField.FS_OPS );
+            environment.observe( Metrics.FS_OPS );
             fileSystem.copy( path, dest );
         }
         catch( FileSystemException e )
@@ -333,7 +333,7 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Deletes a file or directory.
-     *
+     * <p>
      * If the path points to a directory, all of the enclosed files and
      * subdirectories are also deleted.
      *
@@ -345,7 +345,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            environment.addTrackingChange( TrackingField.FS_OPS );
+            environment.observe( Metrics.FS_OPS );
             fileSystem.delete( path );
         }
         catch( FileSystemException e )
@@ -358,14 +358,14 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Opens a file for reading or writing at a path.
-     *
+     * <p>
      * The {@code mode} string can be any of the following:
      * <ul>
      * <li><strong>"r"</strong>: Read mode</li>
      * <li><strong>"w"</strong>: Write mode</li>
      * <li><strong>"a"</strong>: Append mode</li>
      * </ul>
-     *
+     * <p>
      * The mode may also have a "b" at the end, which opens the file in "binary
      * mode". This allows you to read binary files, as well as seek within a file.
      *
@@ -411,7 +411,7 @@ public class FSAPI implements ILuaAPI
     @LuaFunction
     public final Object[] open( String path, String mode ) throws LuaException
     {
-        environment.addTrackingChange( TrackingField.FS_OPS );
+        environment.observe( Metrics.FS_OPS );
         try
         {
             switch( mode )
@@ -516,7 +516,7 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Searches for files matching a string with wildcards.
-     *
+     * <p>
      * 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/&#42;/command*</code> will look for any path starting with
@@ -532,7 +532,7 @@ public class FSAPI implements ILuaAPI
     {
         try
         {
-            environment.addTrackingChange( TrackingField.FS_OPS );
+            environment.observe( Metrics.FS_OPS );
             return fileSystem.find( path );
         }
         catch( FileSystemException e )
@@ -568,10 +568,10 @@ public class FSAPI implements ILuaAPI
 
     /**
      * Get attributes about a specific file or folder.
-     *
+     * <p>
      * 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.
-     *
+     * <p>
      * 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.
      *

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

@@ -207,7 +207,7 @@ public class HTTPAPI implements ILuaAPI
 
         if( !headers.contains( HttpHeaderNames.USER_AGENT ) )
         {
-            headers.set( HttpHeaderNames.USER_AGENT, apiEnvironment.getComputerEnvironment().getUserAgent() );
+            headers.set( HttpHeaderNames.USER_AGENT, apiEnvironment.getGlobalEnvironment().getUserAgent() );
         }
         return headers;
     }

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

@@ -7,11 +7,12 @@ package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
+import dan200.computercraft.core.computer.ComputerEnvironment;
 import dan200.computercraft.core.computer.ComputerSide;
-import dan200.computercraft.core.computer.IComputerEnvironment;
+import dan200.computercraft.core.computer.GlobalEnvironment;
 import dan200.computercraft.core.filesystem.FileSystem;
+import dan200.computercraft.core.metrics.Metric;
 import dan200.computercraft.core.terminal.Terminal;
-import dan200.computercraft.core.tracking.TrackingField;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -29,7 +30,10 @@ public interface IAPIEnvironment
     int getComputerID();
 
     @Nonnull
-    IComputerEnvironment getComputerEnvironment();
+    ComputerEnvironment getComputerEnvironment();
+
+    @Nonnull
+    GlobalEnvironment getGlobalEnvironment();
 
     @Nonnull
     IWorkMonitor getMainThreadMonitor();
@@ -71,10 +75,7 @@ public interface IAPIEnvironment
 
     void cancelTimer( int id );
 
-    void addTrackingChange( @Nonnull TrackingField field, long change );
+    void observe( @Nonnull Metric.Event event, long change );
 
-    default void addTrackingChange( @Nonnull TrackingField field )
-    {
-        addTrackingChange( field, 1 );
-    }
+    void observe( @Nonnull Metric.Counter counter );
 }

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

@@ -39,17 +39,8 @@ public class OSAPI implements ILuaAPI
 
     private int nextAlarmToken = 0;
 
-    private static class Alarm implements Comparable<Alarm>
+    private record Alarm(double time, int day) 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 )
         {
@@ -173,7 +164,7 @@ public class OSAPI implements ILuaAPI
      * 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.
-     *
+     * <p>
      * 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.
@@ -315,13 +306,13 @@ public class OSAPI implements ILuaAPI
     /**
      * Returns the current time depending on the string passed in. This will
      * always be in the range [0.0, 24.0).
-     *
+     * <p>
      * * 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.
-     *
+     * <p>
      * 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).
@@ -363,7 +354,7 @@ public class OSAPI implements ILuaAPI
 
     /**
      * Returns the day depending on the locale specified.
-     *
+     * <p>
      * * 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
@@ -395,7 +386,7 @@ public class OSAPI implements ILuaAPI
 
     /**
      * Returns the number of milliseconds since an epoch depending on the locale.
-     *
+     * <p>
      * * 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
@@ -446,12 +437,12 @@ public class OSAPI implements ILuaAPI
     /**
      * Returns a date string (or table) using a specified format string and
      * optional time to format.
-     *
+     * <p>
      * 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.
-     *
+     * <p>
      * 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

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

@@ -16,7 +16,7 @@ import dan200.computercraft.core.asm.LuaMethod;
 import dan200.computercraft.core.asm.NamedMethod;
 import dan200.computercraft.core.asm.PeripheralMethod;
 import dan200.computercraft.core.computer.ComputerSide;
-import dan200.computercraft.core.tracking.TrackingField;
+import dan200.computercraft.core.metrics.Metrics;
 import dan200.computercraft.shared.util.LuaUtil;
 
 import javax.annotation.Nonnull;
@@ -108,7 +108,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
 
             if( method == null ) throw new LuaException( "No such method " + methodName );
 
-            environment.addTrackingChange( TrackingField.PERIPHERAL_OPS );
+            environment.observe( Metrics.PERIPHERAL_OPS );
             return method.apply( peripheral, context, this, arguments );
         }
 

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

@@ -12,7 +12,7 @@ import dan200.computercraft.core.computer.ComputerSide;
 
 /**
  * Get and set redstone signals adjacent to this computer.
- *
+ * <p>
  * 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.
@@ -21,10 +21,10 @@ import dan200.computercraft.core.computer.ComputerSide;
  * - 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}.
- *
+ * <p>
  * Whenever a redstone input changes, a @{event!redstone} event will be fired. This may be used instead of repeativly
  * polling.
- *
+ * <p>
  * This module may also be referred to as {@code rs}. For example, one may call {@code rs.getSides()} instead of
  * {@link #getSides}.
  *
@@ -47,7 +47,7 @@ import dan200.computercraft.core.computer.ComputerSide;
  *   os.pullEvent("redstone") -- Wait for a change to inputs.
  * end
  * }</pre>
- *
+ * <p>
  * [comparator]: https://minecraft.gamepedia.com/Redstone_Comparator#Subtract_signal_strength "Redstone Comparator on
  * the Minecraft wiki."
  * @cc.module redstone

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

@@ -9,7 +9,6 @@ import dan200.computercraft.api.lua.IArguments;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.lua.LuaFunction;
-import dan200.computercraft.core.computer.IComputerEnvironment;
 import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.shared.util.Colour;
 
@@ -24,12 +23,10 @@ import javax.annotation.Nonnull;
 public class TermAPI extends TermMethods implements ILuaAPI
 {
     private final Terminal terminal;
-    private final IComputerEnvironment environment;
 
     public TermAPI( IAPIEnvironment environment )
     {
         terminal = environment.getTerminal();
-        this.environment = environment.getComputerEnvironment();
     }
 
     @Override
@@ -55,12 +52,7 @@ public class TermAPI extends TermMethods implements ILuaAPI
     {
         int actualColour = 15 - parseColour( colour );
         Colour c = Colour.fromInt( actualColour );
-
-        float[] rgb = c.getRGB();
-
-        Object[] rgbObj = new Object[rgb.length];
-        for( int i = 0; i < rgbObj.length; ++i ) rgbObj[i] = rgb[i];
-        return rgbObj;
+        return new Object[] { c.getR(), c.getG(), c.getB() };
     }
 
     @Nonnull
@@ -69,10 +61,4 @@ public class TermAPI extends TermMethods implements ILuaAPI
     {
         return terminal;
     }
-
-    @Override
-    public boolean isColour()
-    {
-        return environment.isColour();
-    }
 }

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

@@ -37,11 +37,9 @@ public abstract class TermMethods
     @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.
-     *
+     * <p>
      * Unlike functions like {@code write} and {@code print}, this does not wrap the text - it simply copies the
      * text to the current terminal line.
      *
@@ -63,7 +61,7 @@ public abstract class TermMethods
 
     /**
      * Move all positions up (or down) by {@code y} pixels.
-     *
+     * <p>
      * 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.
      *
@@ -247,7 +245,7 @@ public abstract class TermMethods
 
     /**
      * Determine if this terminal supports colour.
-     *
+     * <p>
      * Terminals which do not support colour will still allow writing coloured text/backgrounds, but it will be
      * displayed in greyscale.
      *
@@ -258,15 +256,15 @@ public abstract class TermMethods
     @LuaFunction( { "isColour", "isColor" } )
     public final boolean getIsColour() throws LuaException
     {
-        return isColour();
+        return getTerminal().isColour();
     }
 
     /**
      * Writes {@code text} to the terminal with the specific foreground and background characters.
-     *
+     * <p>
      * 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.
-     *
+     * <p>
      * {@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.
@@ -301,7 +299,7 @@ public abstract class TermMethods
 
     /**
      * Set the palette for a specific colour.
-     *
+     * <p>
      * 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

src/main/java/dan200/computercraft/core/apis/handles/BinaryReadableHandle.java

@@ -249,11 +249,11 @@ public class BinaryReadableHandle extends HandleGeneric
         /**
          * Seek to a new position within the file, changing where bytes are written to. The new position is an offset
          * given by {@code offset}, relative to a start position determined by {@code whence}:
-         *
+         * <p>
          * - {@code "set"}: {@code offset} is relative to the beginning of the file.
          * - {@code "cur"}: Relative to the current position. This is the default.
          * - {@code "end"}: Relative to the end of the file.
-         *
+         * <p>
          * In case of success, {@code seek} returns the new file position from the beginning of the file.
          *
          * @param whence Where the offset is relative to.

src/main/java/dan200/computercraft/core/apis/handles/BinaryWritableHandle.java

@@ -117,11 +117,11 @@ public class BinaryWritableHandle extends HandleGeneric
         /**
          * Seek to a new position within the file, changing where bytes are written to. The new position is an offset
          * given by {@code offset}, relative to a start position determined by {@code whence}:
-         *
+         * <p>
          * - {@code "set"}: {@code offset} is relative to the beginning of the file.
          * - {@code "cur"}: Relative to the current position. This is the default.
          * - {@code "end"}: Relative to the end of the file.
-         *
+         * <p>
          * In case of success, {@code seek} returns the new file position from the beginning of the file.
          *
          * @param whence Where the offset is relative to.

src/main/java/dan200/computercraft/core/apis/handles/HandleGeneric.java

@@ -39,7 +39,7 @@ public abstract class HandleGeneric
 
     /**
      * Close this file, freeing any resources it uses.
-     *
+     * <p>
      * Once a file is closed it may no longer be read or written to.
      *
      * @throws LuaException If the file has already been closed.

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

@@ -13,7 +13,7 @@ import java.util.concurrent.Future;
 
 /**
  * Checks a URL using {@link NetworkUtils#getAddress(String, int, boolean)}}
- *
+ * <p>
  * This requires a DNS lookup, and so needs to occur off-thread.
  */
 public class CheckUrl extends Resource<CheckUrl>

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

@@ -126,7 +126,7 @@ public final class NetworkUtils
 
     /**
      * Create a {@link InetSocketAddress} from a {@link java.net.URI}.
-     *
+     * <p>
      * Note, this may require a DNS lookup, and so should not be executed on the main CC thread.
      *
      * @param uri The URI to fetch.
@@ -141,7 +141,7 @@ public final class NetworkUtils
 
     /**
      * Create a {@link InetSocketAddress} from the resolved {@code host} and port.
-     *
+     * <p>
      * Note, this may require a DNS lookup, and so should not be executed on the main CC thread.
      *
      * @param host The host to resolve.

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

@@ -68,7 +68,7 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
 
     /**
      * Clean up any pending resources
-     *
+     * <p>
      * Note, this may be called multiple times, and so should be thread-safe and
      * avoid any major side effects.
      */

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

@@ -85,8 +85,8 @@ public final class AddressRule
 
         int port = socketAddress.getPort();
         InetAddress address = socketAddress.getAddress();
-        Inet4Address ipv4Address = address instanceof Inet6Address && InetAddresses.is6to4Address( (Inet6Address) address )
-            ? InetAddresses.get6to4IPv4Address( (Inet6Address) address ) : null;
+        Inet4Address ipv4Address = address instanceof Inet6Address inet6 && InetAddresses.is6to4Address( inet6 )
+            ? InetAddresses.get6to4IPv4Address( inet6 ) : null;
 
         for( AddressRule rule : rules )
         {

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

@@ -12,7 +12,7 @@ import dan200.computercraft.core.apis.http.NetworkUtils;
 import dan200.computercraft.core.apis.http.Resource;
 import dan200.computercraft.core.apis.http.ResourceGroup;
 import dan200.computercraft.core.apis.http.options.Options;
-import dan200.computercraft.core.tracking.TrackingField;
+import dan200.computercraft.core.metrics.Metrics;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -148,8 +148,8 @@ public class HttpRequest extends Resource<HttpRequest>
             }
 
             // Add request size to the tracker before opening the connection
-            environment.addTrackingChange( TrackingField.HTTP_REQUESTS, 1 );
-            environment.addTrackingChange( TrackingField.HTTP_UPLOAD, requestBody );
+            environment.observe( Metrics.HTTP_REQUESTS );
+            environment.observe( Metrics.HTTP_UPLOAD, requestBody );
 
             HttpRequestHandler handler = currentRequest = new HttpRequestHandler( this, uri, method, options );
             connectFuture = new Bootstrap()

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

@@ -13,7 +13,7 @@ import dan200.computercraft.core.apis.handles.HandleGeneric;
 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 dan200.computercraft.core.metrics.Metrics;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.CompositeByteBuf;
 import io.netty.channel.ChannelHandlerContext;
@@ -199,7 +199,7 @@ public final class HttpRequestHandler extends SimpleChannelInboundHandler<HttpOb
         }
 
         // Fire off a stats event
-        request.environment().addTrackingChange( TrackingField.HTTP_DOWNLOAD, getHeaderSize( responseHeaders ) + bytes.length );
+        request.environment().observe( Metrics.HTTP_DOWNLOAD, getHeaderSize( responseHeaders ) + bytes.length );
 
         // Prepare to queue an event
         ArrayByteChannel contents = new ArrayByteChannel( bytes );

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

@@ -8,7 +8,7 @@ package dan200.computercraft.core.apis.http.websocket;
 import com.google.common.base.Objects;
 import dan200.computercraft.api.lua.*;
 import dan200.computercraft.core.apis.http.options.Options;
-import dan200.computercraft.core.tracking.TrackingField;
+import dan200.computercraft.core.metrics.Metrics;
 import dan200.computercraft.shared.util.StringUtil;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
@@ -89,7 +89,7 @@ public class WebsocketHandle implements Closeable
             throw new LuaException( "Message is too large" );
         }
 
-        websocket.environment().addTrackingChange( TrackingField.WEBSOCKET_OUTGOING, text.length() );
+        websocket.environment().observe( Metrics.WEBSOCKET_OUTGOING, text.length() );
 
         Channel channel = this.channel;
         if( channel != null )

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

@@ -7,7 +7,7 @@ package dan200.computercraft.core.apis.http.websocket;
 
 import dan200.computercraft.core.apis.http.NetworkUtils;
 import dan200.computercraft.core.apis.http.options.Options;
-import dan200.computercraft.core.tracking.TrackingField;
+import dan200.computercraft.core.metrics.Metrics;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.FullHttpResponse;
@@ -61,18 +61,18 @@ public class WebsocketHandler extends SimpleChannelInboundHandler<Object>
         }
 
         WebSocketFrame frame = (WebSocketFrame) msg;
-        if( frame instanceof TextWebSocketFrame )
+        if( frame instanceof TextWebSocketFrame textFrame )
         {
-            String data = ((TextWebSocketFrame) frame).text();
+            String data = textFrame.text();
 
-            websocket.environment().addTrackingChange( TrackingField.WEBSOCKET_INCOMING, data.length() );
+            websocket.environment().observe( Metrics.WEBSOCKET_INCOMING, data.length() );
             websocket.environment().queueEvent( MESSAGE_EVENT, websocket.address(), data, false );
         }
         else if( frame instanceof BinaryWebSocketFrame )
         {
             byte[] converted = NetworkUtils.toBytes( frame.content() );
 
-            websocket.environment().addTrackingChange( TrackingField.WEBSOCKET_INCOMING, converted.length );
+            websocket.environment().observe( Metrics.WEBSOCKET_INCOMING, converted.length );
             websocket.environment().queueEvent( MESSAGE_EVENT, websocket.address(), converted, true );
         }
         else if( frame instanceof CloseWebSocketFrame closeFrame )

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

@@ -19,7 +19,6 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /**
@@ -51,7 +50,7 @@ public class GenericMethod
     static List<GenericMethod> all()
     {
         if( cache != null ) return cache;
-        return cache = sources.stream().flatMap( GenericMethod::getMethods ).collect( Collectors.toList() );
+        return cache = sources.stream().flatMap( GenericMethod::getMethods ).toList();
     }
 
     public static synchronized void register( @Nonnull GenericSource source )
@@ -69,7 +68,7 @@ public class GenericMethod
     private static Stream<GenericMethod> getMethods( GenericSource source )
     {
         Class<?> klass = source.getClass();
-        PeripheralType type = source instanceof GenericPeripheral ? ((GenericPeripheral) source).getType() : null;
+        PeripheralType type = source instanceof GenericPeripheral generic ? generic.getType() : null;
 
         return Arrays.stream( klass.getDeclaredMethods() )
             .map( method -> {

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

@@ -9,7 +9,7 @@ import java.util.function.BiConsumer;
 
 /**
  * A Lua object which exposes additional methods.
- *
+ * <p>
  * 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.
  */
@@ -21,9 +21,9 @@ public interface ObjectSource
     {
         for( NamedMethod<T> method : generator.getMethods( object.getClass() ) ) accept.accept( object, method );
 
-        if( object instanceof ObjectSource )
+        if( object instanceof ObjectSource source )
         {
-            for( Object extra : ((ObjectSource) object).getExtra() )
+            for( Object extra : source.getExtra() )
             {
                 for( NamedMethod<T> method : generator.getMethods( extra.getClass() ) ) accept.accept( extra, method );
             }

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

@@ -52,7 +52,7 @@ final class Reflect
         Type underlying = root;
         while( true )
         {
-            if( underlying instanceof Class<?> ) return (Class<?>) underlying;
+            if( underlying instanceof Class<?> klass ) return klass;
 
             if( underlying instanceof ParameterizedType type )
             {
@@ -61,7 +61,7 @@ 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 TypeVariable<?> var && var.getName().startsWith( "capture#" ) )
                         {
                             continue;
                         }

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

@@ -7,16 +7,21 @@ package dan200.computercraft.core.computer;
 
 import com.google.common.base.Objects;
 import dan200.computercraft.api.lua.ILuaAPI;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.ILuaTask;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
+import dan200.computercraft.core.ComputerContext;
 import dan200.computercraft.core.apis.IAPIEnvironment;
+import dan200.computercraft.core.computer.mainthread.MainThreadScheduler;
 import dan200.computercraft.core.filesystem.FileSystem;
 import dan200.computercraft.core.terminal.Terminal;
 
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * Represents a computer which may exist in-world or elsewhere.
- *
+ * <p>
  * Note, this class has several (read: far, far too many) responsibilities, so can get a little unwieldy at times.
  *
  * <ul>
@@ -24,7 +29,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
  * <li>Keeps track of whether the computer is on and blinking.</li>
  * <li>Monitors whether the computer's visible state (redstone, on/off/blinking) has changed.</li>
  * <li>Passes commands and events to the {@link ComputerExecutor}.</li>
- * <li>Passes main thread tasks to the {@link MainThreadExecutor}.</li>
+ * <li>Passes main thread tasks to the {@link MainThreadScheduler.Executor}.</li>
  * </ul>
  */
 public class Computer
@@ -32,36 +37,46 @@ public class Computer
     private static final int START_DELAY = 50;
 
     // Various properties of the computer
-    private int id;
+    private final int id;
     private String label = null;
 
     // Read-only fields about the computer
-    private final IComputerEnvironment environment;
+    private final GlobalEnvironment globalEnvironment;
     private final Terminal terminal;
     private final ComputerExecutor executor;
-    private final MainThreadExecutor serverExecutor;
+    private final MainThreadScheduler.Executor serverExecutor;
+
+    /**
+     * An internal counter for {@link ILuaTask} ids.
+     *
+     * @see ILuaContext#issueMainThreadTask(ILuaTask)
+     * @see #getUniqueTaskId()
+     */
+    private final AtomicLong lastTaskId = new AtomicLong();
 
     // Additional state about the computer and its environment.
     private boolean blinking = false;
-    private final Environment internalEnvironment = new Environment( this );
+    private final Environment internalEnvironment;
     private final AtomicBoolean externalOutputChanged = new AtomicBoolean();
 
     private boolean startRequested;
     private int ticksSinceStart = -1;
 
-    public Computer( IComputerEnvironment environment, Terminal terminal, int id )
+    public Computer( ComputerContext context, ComputerEnvironment environment, Terminal terminal, int id )
     {
+        if( id < 0 ) throw new IllegalStateException( "Id has not been assigned" );
         this.id = id;
-        this.environment = environment;
+        globalEnvironment = context.globalEnvironment();
         this.terminal = terminal;
 
-        executor = new ComputerExecutor( this );
-        serverExecutor = new MainThreadExecutor( this );
+        internalEnvironment = new Environment( this, environment );
+        executor = new ComputerExecutor( this, environment, context );
+        serverExecutor = context.mainThreadScheduler().createExecutor( environment.getMetrics() );
     }
 
-    IComputerEnvironment getComputerEnvironment()
+    GlobalEnvironment getGlobalEnvironment()
     {
-        return environment;
+        return globalEnvironment;
     }
 
     FileSystem getFileSystem()
@@ -115,7 +130,7 @@ public class Computer
     }
 
     /**
-     * Queue a task to be run on the main thread, using {@link MainThread}.
+     * Queue a task to be run on the main thread, using {@link MainThreadScheduler}.
      *
      * @param runnable The task to run
      * @return If the task was successfully queued (namely, whether there is space on it).
@@ -135,20 +150,6 @@ public class Computer
         return id;
     }
 
-    public int assignID()
-    {
-        if( id < 0 )
-        {
-            id = environment.assignNewID();
-        }
-        return id;
-    }
-
-    public void setID( int id )
-    {
-        this.id = id;
-    }
-
     public String getLabel()
     {
         return label;
@@ -216,4 +217,9 @@ public class Computer
     {
         executor.addApi( api );
     }
+
+    long getUniqueTaskId()
+    {
+        return lastTaskId.incrementAndGet();
+    }
 }