Un-localise paths in mount error messages

This is probably a little more complex than it needs to be, as we try to
handle the mounts as well (which generally don't error).

Fixes #229

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

@@ -0,0 +1,41 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.api.filesystem;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * An {@link IOException} which occurred on a specific file.
+ *
+ * This may be thrown from a {@link IMount} or {@link IWritableMount} to give more information about a failure.
+ */
+public class FileOperationException extends IOException
+{
+    private static final long serialVersionUID = -8809108200853029849L;
+
+    private String filename;
+
+    public FileOperationException( @Nullable String filename, @Nonnull String message )
+    {
+        super( Objects.requireNonNull( message, "message cannot be null" ) );
+        this.filename = filename;
+    }
+
+    public FileOperationException( String message )
+    {
+        super( Objects.requireNonNull( message, "message cannot be null" ) );
+    }
+
+    @Nullable
+    public String getFilename()
+    {
+        return filename;
+    }
+}

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

@@ -6,6 +6,7 @@
 
 package dan200.computercraft.core.filesystem;
 
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
@@ -95,7 +96,7 @@ public class ComboMount implements IMount
         }
         else
         {
-            throw new IOException( "/" + path + ": Not a directory" );
+            throw new FileOperationException( path, "Not a directory" );
         }
     }
 
@@ -110,7 +111,7 @@ public class ComboMount implements IMount
                 return part.getSize( path );
             }
         }
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -126,7 +127,7 @@ public class ComboMount implements IMount
                 return part.openForRead( path );
             }
         }
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -141,6 +142,6 @@ public class ComboMount implements IMount
                 return part.openChannelForRead( path );
             }
         }
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 }

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

@@ -6,6 +6,7 @@
 
 package dan200.computercraft.core.filesystem;
 
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
@@ -44,7 +45,7 @@ public class EmptyMount implements IMount
     @Deprecated
     public InputStream openForRead( @Nonnull String path ) throws IOException
     {
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -52,6 +53,6 @@ public class EmptyMount implements IMount
     @Deprecated
     public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
     {
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 }

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

@@ -7,6 +7,7 @@
 package dan200.computercraft.core.filesystem;
 
 import com.google.common.collect.Sets;
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IWritableMount;
 
 import javax.annotation.Nonnull;
@@ -167,12 +168,12 @@ public class FileMount implements IWritableMount
     {
         if( !created() )
         {
-            if( !path.isEmpty() ) throw new IOException( "/" + path + ": Not a directory" );
+            if( !path.isEmpty() ) throw new FileOperationException( path, "Not a directory" );
             return;
         }
 
         File file = getRealPath( path );
-        if( !file.exists() || !file.isDirectory() ) throw new IOException( "/" + path + ": Not a directory" );
+        if( !file.exists() || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
 
         String[] paths = file.list();
         for( String subPath : paths )
@@ -194,7 +195,7 @@ public class FileMount implements IWritableMount
             if( file.exists() ) return file.isDirectory() ? 0 : file.length();
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -208,7 +209,7 @@ public class FileMount implements IWritableMount
             if( file.exists() && !file.isDirectory() ) return new FileInputStream( file );
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -221,7 +222,7 @@ public class FileMount implements IWritableMount
             if( file.exists() && !file.isDirectory() ) return FileChannel.open( file.toPath(), READ_OPTIONS );
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     // IWritableMount implementation
@@ -233,7 +234,7 @@ public class FileMount implements IWritableMount
         File file = getRealPath( path );
         if( file.exists() )
         {
-            if( !file.isDirectory() ) throw new IOException( "/" + path + ": File exists" );
+            if( !file.isDirectory() ) throw new FileOperationException( path, "File exists" );
             return;
         }
 
@@ -247,7 +248,7 @@ public class FileMount implements IWritableMount
 
         if( getRemainingSpace() < dirsToCreate * MINIMUM_FILE_SIZE )
         {
-            throw new IOException( "/" + path + ": Out of space" );
+            throw new FileOperationException( path, "Out of space" );
         }
 
         if( file.mkdirs() )
@@ -256,14 +257,14 @@ public class FileMount implements IWritableMount
         }
         else
         {
-            throw new IOException( "/" + path + ": Access denied" );
+            throw new FileOperationException( path, "Access denied" );
         }
     }
 
     @Override
     public void delete( @Nonnull String path ) throws IOException
     {
-        if( path.isEmpty() ) throw new IOException( "/" + path + ": Access denied" );
+        if( path.isEmpty() ) throw new FileOperationException( path, "Access denied" );
 
         if( created() )
         {
@@ -319,7 +320,7 @@ public class FileMount implements IWritableMount
     {
         create();
         File file = getRealPath( path );
-        if( file.exists() && file.isDirectory() ) throw new IOException( "/" + path + ": Cannot write to directory" );
+        if( file.exists() && file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
 
         if( file.exists() )
         {
@@ -327,7 +328,7 @@ public class FileMount implements IWritableMount
         }
         else if( getRemainingSpace() < MINIMUM_FILE_SIZE )
         {
-            throw new IOException( "/" + path + ": Out of space" );
+            throw new FileOperationException( path, "Out of space" );
         }
         m_usedSpace += MINIMUM_FILE_SIZE;
 
@@ -340,12 +341,12 @@ public class FileMount implements IWritableMount
     {
         if( !created() )
         {
-            throw new IOException( "/" + path + ": No such file" );
+            throw new FileOperationException( path, "No such file" );
         }
 
         File file = getRealPath( path );
-        if( !file.exists() ) throw new IOException( "/" + path + ": No such file" );
+        if( !file.exists() ) throw new FileOperationException( path, "No such file" );
-        if( file.isDirectory() ) throw new IOException( "/" + path + ": Cannot write to directory" );
+        if( file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
 
         // Allowing seeking when appending is not recommended, so we use a separate channel.
         return new WritableCountingChannel(

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

@@ -8,6 +8,7 @@ package dan200.computercraft.core.filesystem;
 
 import com.google.common.io.ByteStreams;
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IFileSystem;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
@@ -107,7 +108,7 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -122,12 +123,12 @@ public class FileSystem
                 }
                 else
                 {
-                    throw new FileSystemException( "/" + path + ": Not a directory" );
+                    throw localExceptionOf( path, "Not a directory" );
                 }
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -149,12 +150,12 @@ public class FileSystem
                 }
                 else
                 {
-                    throw new FileSystemException( "/" + path + ": No such file" );
+                    throw localExceptionOf( path, "No such file" );
                 }
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -169,12 +170,12 @@ public class FileSystem
                 }
                 else
                 {
-                    throw new FileSystemException( "/" + path + ": No such file" );
+                    throw localExceptionOf( path, "No such file" );
                 }
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -182,19 +183,14 @@ public class FileSystem
 
         public void makeDirectory( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
-            {
+
-                throw new FileSystemException( "/" + path + ": Access denied" );
+            path = toLocal( path );
-            }
             try
             {
-                path = toLocal( path );
                 if( m_mount.exists( path ) )
                 {
-                    if( !m_mount.isDirectory( path ) )
+                    if( !m_mount.isDirectory( path ) ) throw localExceptionOf( path, "File exists" );
-                    {
-                        throw new FileSystemException( "/" + path + ": File exists" );
-                    }
                 }
                 else
                 {
@@ -203,16 +199,14 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
         public void delete( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
-            {
+
-                throw new FileSystemException( "/" + path + ": Access denied" );
-            }
             try
             {
                 path = toLocal( path );
@@ -227,22 +221,20 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
         public WritableByteChannel openForWrite( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
-            {
+
-                throw new FileSystemException( "/" + path + ": Access denied" );
+            path = toLocal( path );
-            }
             try
             {
-                path = toLocal( path );
                 if( m_mount.exists( path ) && m_mount.isDirectory( path ) )
                 {
-                    throw new FileSystemException( "/" + path + ": Cannot write to directory" );
+                    throw localExceptionOf( path, "Cannot write to directory" );
                 }
                 else
                 {
@@ -263,19 +255,17 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
         public WritableByteChannel openForAppend( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
-            {
+
-                throw new FileSystemException( "/" + path + ": Access denied" );
+            path = toLocal( path );
-            }
             try
             {
-                path = toLocal( path );
                 if( !m_mount.exists( path ) )
                 {
                     if( !path.isEmpty() )
@@ -290,7 +280,7 @@ public class FileSystem
                 }
                 else if( m_mount.isDirectory( path ) )
                 {
-                    throw new FileSystemException( "/" + path + ": Cannot write to directory" );
+                    throw localExceptionOf( path, "Cannot write to directory" );
                 }
                 else
                 {
@@ -303,16 +293,36 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
-        // private members
-
         private String toLocal( String path )
         {
             return FileSystem.toLocal( path, m_location );
         }
+
+        private FileSystemException localExceptionOf( IOException e )
+        {
+            if( !m_location.isEmpty() && e instanceof FileOperationException )
+            {
+                FileOperationException ex = (FileOperationException) e;
+                if( ex.getFilename() != null ) return localExceptionOf( ex.getFilename(), ex.getMessage() );
+            }
+
+            return new FileSystemException( e.getMessage() );
+        }
+
+        private FileSystemException localExceptionOf( String path, String message )
+        {
+            if( !m_location.isEmpty() ) path = path.isEmpty() ? m_location : m_location + "/" + path;
+            return exceptionOf( path, message );
+        }
+
+        private static FileSystemException exceptionOf( String path, String message )
+        {
+            return new FileSystemException( "/" + path + ": " + message );
+        }
     }
 
     private final FileSystemWrapperMount m_wrapper = new FileSystemWrapperMount( this );

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

@@ -9,6 +9,7 @@ package dan200.computercraft.core.filesystem;
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.io.ByteStreams;
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.core.apis.handles.ArrayByteChannel;
 import dan200.computercraft.shared.util.IoUtil;
@@ -166,7 +167,7 @@ public class JarMount implements IMount
     public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
     {
         FileEntry file = get( path );
-        if( file == null || !file.isDirectory() ) throw new IOException( "/" + path + ": Not a directory" );
+        if( file == null || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
 
         file.list( contents );
     }
@@ -176,7 +177,7 @@ public class JarMount implements IMount
     {
         FileEntry file = get( path );
         if( file != null ) return file.size;
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -218,7 +219,7 @@ public class JarMount implements IMount
             }
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     private static class FileEntry

src/test/resources/test-rom/spec/apis/fs_spec.lua

@@ -11,4 +11,99 @@ describe("The fs library", function()
             expect.error(fs.complete, "", "", true, 1):eq("bad argument #4 (expected boolean, got number)")
         end)
     end)
+
+    describe("fs.list", function()
+        it("fails on files", function()
+            expect.error(fs.list, "rom/startup.lua"):eq("/rom/startup.lua: Not a directory")
+            expect.error(fs.list, "startup.lua"):eq("/startup.lua: Not a directory")
+        end)
+
+        it("fails on non-existent nodes", function()
+            expect.error(fs.list, "rom/x"):eq("/rom/x: Not a directory")
+            expect.error(fs.list, "x"):eq("/x: Not a directory")
+        end)
+    end)
+
+    describe("fs.list", function()
+        it("fails on files", function()
+            expect.error(fs.list, "rom/startup.lua"):eq("/rom/startup.lua: Not a directory")
+            expect.error(fs.list, "startup.lua"):eq("/startup.lua: Not a directory")
+        end)
+
+        it("fails on non-existent nodes", function()
+            expect.error(fs.list, "rom/x"):eq("/rom/x: Not a directory")
+            expect.error(fs.list, "x"):eq("/x: Not a directory")
+        end)
+    end)
+
+    describe("fs.getSize", function()
+        it("fails on non-existent nodes", function()
+            expect.error(fs.getSize, "rom/x"):eq("/rom/x: No such file")
+            expect.error(fs.getSize, "x"):eq("/x: No such file")
+        end)
+    end)
+
+    describe("fs.open", function()
+        describe("reading", function()
+            it("fails on directories", function()
+                expect { fs.open("rom", "r") }:same { nil, "/rom: No such file" }
+                expect { fs.open("", "r") }:same { nil, "/: No such file" }
+            end)
+
+            it("fails on non-existent nodes", function()
+                expect { fs.open("rom/x", "r") }:same { nil, "/rom/x: No such file" }
+                expect { fs.open("x", "r") }:same { nil, "/x: No such file" }
+            end)
+        end)
+
+        describe("writing", function()
+            it("fails on directories", function()
+                expect { fs.open("", "w") }:same { nil, "/: Cannot write to directory" }
+            end)
+
+            it("fails on read-only mounts", function()
+                expect { fs.open("rom/x", "w") }:same { nil, "/rom/x: Access denied" }
+            end)
+        end)
+
+        describe("appending", function()
+            it("fails on directories", function()
+                expect { fs.open("", "a") }:same { nil, "/: Cannot write to directory" }
+            end)
+
+            it("fails on read-only mounts", function()
+                expect { fs.open("rom/x", "a") }:same { nil, "/rom/x: Access denied" }
+            end)
+        end)
+    end)
+
+    describe("fs.makeDir", function()
+        it("fails on files", function()
+            expect.error(fs.makeDir, "startup.lua"):eq("/startup.lua: File exists")
+        end)
+
+        it("fails on read-only mounts", function()
+            expect.error(fs.makeDir, "rom/x"):eq("/rom/x: Access denied")
+        end)
+    end)
+
+    describe("fs.delete", function()
+        it("fails on read-only mounts", function()
+            expect.error(fs.delete, "rom/x"):eq("/rom/x: Access denied")
+        end)
+    end)
+
+    describe("fs.copy", function()
+        it("fails on read-only mounts", function()
+            expect.error(fs.copy, "rom", "rom/startup"):eq("/rom/startup: Access denied")
+        end)
+    end)
+
+    describe("fs.move", function()
+        it("fails on read-only mounts", function()
+            expect.error(fs.move, "rom", "rom/move"):eq("Access denied")
+            expect.error(fs.move, "test-files", "rom/move"):eq("Access denied")
+            expect.error(fs.move, "rom", "test-files"):eq("Access denied")
+        end)
+    end)
 end)