fix: first part of syncing with Tweaked codebase

includes: file drag'n'drop (now doesn't work in Tweaked) and no inventory mode for left hand pocket computer

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

@@ -9,17 +9,18 @@ package dan200.computercraft.api.lua;
 import javax.annotation.Nonnull;
 
 /**
- * An interface passed to peripherals and {@link IDynamicLuaObject}s by computers or turtles, providing methods that allow the peripheral call to interface
+ * An interface passed to peripherals and {@link IDynamicLuaObject}s by computers or turtles, providing methods
- * with the computer.
+ * that allow the peripheral call to interface with the computer.
  */
 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
+     * Queue a task to be executed on the main server thread at the beginning of next tick, but do not wait for it to
-     * need to interact with the world in a thread-safe manner but do not care about the result or you wish to run asynchronously.
+     * 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.
      *
-     * 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
+     * When the task has finished, it will enqueue a {@code task_completed} event, which takes the task id, a success
-     * error message if it failed.
+     * value and the return values, or an error message if it failed.
      *
      * @param task The task to execute on the main thread.
      * @return The "id" of the task. This will be the first argument to the {@code task_completed} event.
@@ -27,4 +28,18 @@ public interface ILuaContext
      * @see LuaFunction#mainThread() To run functions on the main thread and return their results synchronously.
      */
     long issueMainThreadTask( @Nonnull ILuaTask task ) throws LuaException;
+
+    /**
+     * 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.
+     *
+     * 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.
+     *
+     * @param task The task to execute on the main thread.
+     * @return The objects returned by {@code task}.
+     * @throws LuaException If the task could not be queued, or if the task threw an exception.
+     */
+    @Nonnull
+    MethodResult executeMainThreadTask( @Nonnull ILuaTask task ) throws LuaException;
 }

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

@@ -1,18 +0,0 @@
-/*
- * This file is part of the public ComputerCraft API - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2021. 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.lua;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
-public interface ILuaObject
-{
-    @Nonnull
-    String[] getMethodNames();
-
-    @Nullable
-    Object[] callMethod( @Nonnull ILuaContext context, int method, @Nonnull Object[] arguments ) throws LuaException, InterruptedException;
-}

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

@@ -6,12 +6,15 @@
 
 package dan200.computercraft.api.pocket;
 
+import dan200.computercraft.shared.util.NonNullSupplier;
+import net.minecraft.item.Item;
 import net.minecraft.item.ItemConvertible;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.Util;
 
 import javax.annotation.Nonnull;
+import java.util.function.Supplier;
 
 /**
  * A base class for {@link IPocketUpgrade}s.
@@ -22,27 +25,49 @@ public abstract class AbstractPocketUpgrade implements IPocketUpgrade
 {
     private final Identifier id;
     private final String adjective;
-    private final ItemStack stack;
+    private final NonNullSupplier<ItemStack> stack;
 
-    protected AbstractPocketUpgrade( Identifier id, ItemConvertible item )
+    protected AbstractPocketUpgrade( Identifier id, String adjective, NonNullSupplier<ItemStack> stack )
-    {
-        this( id, Util.createTranslationKey( "upgrade", id ) + ".adjective", item );
-    }
-
-    protected AbstractPocketUpgrade( Identifier id, String adjective, ItemConvertible item )
-    {
-        this.id = id;
-        this.adjective = adjective;
-        stack = new ItemStack( item );
-    }
-
-    protected AbstractPocketUpgrade( Identifier id, String adjective, ItemStack stack )
     {
         this.id = id;
         this.adjective = adjective;
         this.stack = stack;
     }
 
+    protected AbstractPocketUpgrade( Identifier id, NonNullSupplier<ItemStack> item )
+    {
+        this( id, Util.createTranslationKey( "upgrade", id ) + ".adjective", item );
+    }
+
+    protected AbstractPocketUpgrade( Identifier id, String adjective, ItemStack stack )
+    {
+        this( id, adjective, () -> stack );
+    }
+
+    protected AbstractPocketUpgrade( Identifier id, ItemStack stack )
+    {
+        this( id, () -> stack );
+    }
+
+    protected AbstractPocketUpgrade( Identifier id, String adjective, ItemConvertible item )
+    {
+        this( id, adjective, new CachedStack( () -> item ) );
+    }
+
+    protected AbstractPocketUpgrade( Identifier id, ItemConvertible item )
+    {
+        this( id, new CachedStack( () -> item ) );
+    }
+
+    protected AbstractPocketUpgrade( Identifier id, String adjective, Supplier<? extends ItemConvertible> item )
+    {
+        this( id, adjective, new CachedStack( item ) );
+    }
+
+    protected AbstractPocketUpgrade( Identifier id, Supplier<? extends ItemConvertible> item )
+    {
+        this( id, new CachedStack( item ) );
+    }
 
     @Nonnull
     @Override
@@ -62,6 +87,32 @@ public abstract class AbstractPocketUpgrade implements IPocketUpgrade
     @Override
     public final ItemStack getCraftingItem()
     {
-        return stack;
+        return stack.get();
+    }
+
+    /**
+     * Caches the construction of an item stack.
+     *
+     * @see dan200.computercraft.api.turtle.AbstractTurtleUpgrade For explanation of this class.
+     */
+    private static final class CachedStack implements NonNullSupplier<ItemStack>
+    {
+        private final Supplier<? extends ItemConvertible> provider;
+        private Item item;
+        private ItemStack stack;
+
+        CachedStack( Supplier<? extends ItemConvertible> provider )
+        {
+            this.provider = provider;
+        }
+
+        @Nonnull
+        @Override
+        public ItemStack get()
+        {
+            Item item = provider.get().asItem();
+            if( item == this.item && stack != null ) return stack;
+            return stack = new ItemStack( this.item = item );
+        }
     }
 }

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

@@ -6,12 +6,15 @@
 
 package dan200.computercraft.api.turtle;
 
+import dan200.computercraft.shared.util.NonNullSupplier;
+import net.minecraft.item.Item;
 import net.minecraft.item.ItemConvertible;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.Util;
 
 import javax.annotation.Nonnull;
+import java.util.function.Supplier;
 
 /**
  * A base class for {@link ITurtleUpgrade}s.
@@ -23,14 +26,9 @@ public abstract class AbstractTurtleUpgrade implements ITurtleUpgrade
     private final Identifier id;
     private final TurtleUpgradeType type;
     private final String adjective;
-    private final ItemStack stack;
+    private final NonNullSupplier<ItemStack> stack;
 
-    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, String adjective, ItemConvertible item )
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, String adjective, NonNullSupplier<ItemStack> stack )
-    {
-        this( id, type, adjective, new ItemStack( item ) );
-    }
-
-    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, String adjective, ItemStack stack )
     {
         this.id = id;
         this.type = type;
@@ -38,16 +36,40 @@ public abstract class AbstractTurtleUpgrade implements ITurtleUpgrade
         this.stack = stack;
     }
 
-    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, ItemConvertible item )
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, NonNullSupplier<ItemStack> stack )
-    {
-        this( id, type, new ItemStack( item ) );
-    }
-
-    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, ItemStack stack )
     {
         this( id, type, Util.createTranslationKey( "upgrade", id ) + ".adjective", stack );
     }
 
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, String adjective, ItemStack stack )
+    {
+        this( id, type, adjective, () -> stack );
+    }
+
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, ItemStack stack )
+    {
+        this( id, type, () -> stack );
+    }
+
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, String adjective, ItemConvertible item )
+    {
+        this( id, type, adjective, new CachedStack( () -> item ) );
+    }
+
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, ItemConvertible item )
+    {
+        this( id, type, new CachedStack( () -> item ) );
+    }
+
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, String adjective, Supplier<? extends ItemConvertible> item )
+    {
+        this( id, type, adjective, new CachedStack( item ) );
+    }
+
+    protected AbstractTurtleUpgrade( Identifier id, TurtleUpgradeType type, Supplier<? extends ItemConvertible> item )
+    {
+        this( id, type, new CachedStack( item ) );
+    }
 
     @Nonnull
     @Override
@@ -74,6 +96,32 @@ public abstract class AbstractTurtleUpgrade implements ITurtleUpgrade
     @Override
     public final ItemStack getCraftingItem()
     {
-        return stack;
+        return stack.get();
+    }
+
+    /**
+     * A supplier which converts an item into an item stack.
+     *
+     * Constructing item stacks is somewhat expensive due to attaching capabilities. We cache it if given a consistent item.
+     */
+    private static final class CachedStack implements NonNullSupplier<ItemStack>
+    {
+        private final Supplier<? extends ItemConvertible> provider;
+        private Item item;
+        private ItemStack stack;
+
+        CachedStack( Supplier<? extends ItemConvertible> provider )
+        {
+            this.provider = provider;
+        }
+
+        @Nonnull
+        @Override
+        public ItemStack get()
+        {
+            Item item = provider.get().asItem();
+            if( item == this.item && stack != null ) return stack;
+            return stack = new ItemStack( this.item = item );
+        }
     }
 }

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

@@ -1,10 +1,16 @@
 package dan200.computercraft.client.gui;
 
+import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.shared.computer.core.ClientComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
+import dan200.computercraft.shared.computer.upload.FileUpload;
+import dan200.computercraft.shared.computer.upload.UploadResult;
+import dan200.computercraft.shared.network.NetworkHandler;
+import dan200.computercraft.shared.network.server.ContinueUploadMessage;
+import dan200.computercraft.shared.network.server.UploadFileMessage;
 import net.minecraft.client.gui.screen.ingame.HandledScreen;
 import net.minecraft.client.util.math.MatrixStack;
 import net.minecraft.entity.player.PlayerInventory;
@@ -13,6 +19,15 @@ import net.minecraft.text.TranslatableText;
 import org.lwjgl.glfw.GLFW;
 
 import javax.annotation.Nonnull;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.SeekableByteChannel;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 
 public abstract class ComputerScreenBase <T extends ContainerComputerBase> extends HandledScreen<T> {
 
@@ -94,4 +109,117 @@ public abstract class ComputerScreenBase <T extends ContainerComputerBase> exten
         // Skip rendering labels.
     }
 
+    @Override
+    public void filesDragged( @Nonnull List<Path> files )
+    {
+        // TODO: this thing doesn't work in Tweaked at this moment
+        if (true) return;
+        if( files.isEmpty() ) return;
+
+        if( computer == null || !computer.isOn() )
+        {
+            alert( UploadResult.FAILED_TITLE, UploadResult.COMPUTER_OFF_MSG );
+            return;
+        }
+
+        long size = 0;
+
+        List<FileUpload> toUpload = new ArrayList<>();
+        for( Path file : files )
+        {
+            // TODO: Recurse directories? If so, we probably want to shunt this off-thread.
+            if( !Files.isRegularFile( file ) ) continue;
+
+            try( SeekableByteChannel sbc = Files.newByteChannel( file ) )
+            {
+                long fileSize = sbc.size();
+                if( fileSize > UploadFileMessage.MAX_SIZE || (size += fileSize) >= UploadFileMessage.MAX_SIZE )
+                {
+                    alert( UploadResult.FAILED_TITLE, UploadResult.TOO_MUCH_MSG );
+                    return;
+                }
+
+                String name = file.getFileName().toString();
+                if( name.length() > UploadFileMessage.MAX_FILE_NAME )
+                {
+                    alert( UploadResult.FAILED_TITLE, new TranslatableText( "gui.computercraft.upload.failed.name_too_long" ) );
+                    return;
+                }
+
+                ByteBuffer buffer = ByteBuffer.allocateDirect( (int) fileSize );
+                sbc.read( buffer );
+                buffer.flip();
+
+                byte[] digest = FileUpload.getDigest( buffer );
+                if( digest == null )
+                {
+                    alert( UploadResult.FAILED_TITLE, new TranslatableText( "gui.computercraft.upload.failed.corrupted" ) );
+                    return;
+                }
+
+                buffer.rewind();
+                toUpload.add( new FileUpload( name, buffer, digest ) );
+            }
+            catch( IOException e )
+            {
+                ComputerCraft.log.error( "Failed uploading files", e );
+                alert( UploadResult.FAILED_TITLE, new TranslatableText( "gui.computercraft.upload.failed.generic", "Cannot compute checksum" ) );
+            }
+        }
+
+        if( toUpload.size() > UploadFileMessage.MAX_FILES )
+        {
+            alert( UploadResult.FAILED_TITLE, new TranslatableText( "gui.computercraft.upload.failed.too_many_files" ) );
+            return;
+        }
+
+        if( toUpload.size() > 0 )
+        {
+            UploadFileMessage.send( computer.getInstanceID(), toUpload );
+        }
+    }
+
+    public void uploadResult( UploadResult result, Text message )
+    {
+        switch( result )
+        {
+            case SUCCESS:
+                alert( UploadResult.SUCCESS_TITLE, message );
+                break;
+            case ERROR:
+                alert( UploadResult.FAILED_TITLE, message );
+                break;
+            case CONFIRM_OVERWRITE:
+                OptionScreen.show(
+                    client, UploadResult.UPLOAD_OVERWRITE, message,
+                    Arrays.asList(
+                        OptionScreen.newButton( CANCEL, b -> cancelUpload() ),
+                        OptionScreen.newButton( OVERWRITE, b -> continueUpload() )
+                    ),
+                    this::cancelUpload
+                );
+                break;
+        }
+    }
+
+    private void continueUpload()
+    {
+        if( client.currentScreen instanceof OptionScreen ) ((OptionScreen) client.currentScreen).disable();
+        NetworkHandler.sendToServer( new ContinueUploadMessage( computer.getInstanceID(), true ) );
+    }
+
+    private void cancelUpload()
+    {
+        client.setScreen( this );
+        NetworkHandler.sendToServer( new ContinueUploadMessage( computer.getInstanceID(), false ) );
+    }
+
+    private void alert( Text title, Text message )
+    {
+        OptionScreen.show( client, title, message,
+            Collections.singletonList( OptionScreen.newButton( OK, b -> client.setScreen( this ) ) ),
+            () -> client.setScreen( this )
+        );
+    }
+
 }

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

@@ -11,10 +11,10 @@ import dan200.computercraft.client.gui.widgets.ComputerSidebar;
 import dan200.computercraft.client.gui.widgets.WidgetTerminal;
 import dan200.computercraft.client.render.ComputerBorderRenderer;
 import dan200.computercraft.client.render.RenderTypes;
-import dan200.computercraft.shared.computer.inventory.ContainerComputer;
+//import dan200.computercraft.shared.computer.inventory.ContainerComputer;
 import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
-import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
+//import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
 import net.minecraft.client.util.math.MatrixStack;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.text.Text;
@@ -39,12 +39,12 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Computer
         backgroundHeight = WidgetTerminal.getHeight( termHeight ) + BORDER * 2;
     }
 
-    public static GuiComputer<ContainerComputer> create( ContainerComputer container, PlayerInventory inventory, Text component )
+    public static GuiComputer<ContainerComputerBase> create( ContainerComputerBase container, PlayerInventory inventory, Text component )
     {
         return new GuiComputer<>( container, inventory, component, ComputerCraft.computerTermWidth, ComputerCraft.computerTermHeight );
     }
 
-    public static GuiComputer<ContainerPocketComputer> createPocket( ContainerPocketComputer container, PlayerInventory inventory, Text component )
+    public static GuiComputer<ContainerComputerBase> createPocket( ContainerComputerBase container, PlayerInventory inventory, Text component )
     {
         return new GuiComputer<>( container, inventory, component, ComputerCraft.pocketTermWidth, ComputerCraft.pocketTermHeight );
     }

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

@@ -0,0 +1,108 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.gui;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.client.gui.widgets.WidgetTerminal;
+import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
+import net.minecraft.client.font.TextRenderer;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.screen.ingame.ScreenHandlerProvider;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.text.OrderedText;
+import net.minecraft.text.Text;
+import net.minecraft.text.TranslatableText;
+import org.lwjgl.glfw.GLFW;
+
+import javax.annotation.Nonnull;
+import java.util.List;
+
+public class NoTermComputerScreen<T extends ContainerComputerBase> extends Screen implements ScreenHandlerProvider<T>
+{
+    private final T menu;
+    private WidgetTerminal terminal;
+
+    public NoTermComputerScreen(T menu, PlayerInventory player, Text title )
+    {
+        super( title );
+        this.menu = menu;
+    }
+
+    @Nonnull
+    @Override
+    public T getScreenHandler()
+    {
+        return menu;
+    }
+
+    @Override
+    protected void init()
+    {
+        super.init();
+        client.keyboard.setRepeatEvents( true );
+
+        terminal = addDrawableChild( new WidgetTerminal( (ClientComputer) menu.getComputer(), 0, 0, ComputerCraft.pocketTermWidth, ComputerCraft.pocketTermHeight ) );
+        terminal.visible = false;
+        terminal.active = false;
+        setFocused( terminal );
+    }
+
+    @Override
+    public final void removed()
+    {
+        super.removed();
+        client.keyboard.setRepeatEvents( false );
+    }
+
+    @Override
+    public final void tick()
+    {
+        super.tick();
+        terminal.update();
+    }
+
+    @Override
+    public void onClose()
+    {
+        client.player.closeHandledScreen();
+        super.onClose();
+    }
+
+    @Override
+    public boolean isPauseScreen()
+    {
+        return false;
+    }
+
+    @Override
+    public final boolean keyPressed( int key, int scancode, int modifiers )
+    {
+        // Forward the tab key to the terminal, rather than moving between controls.
+        if( key == GLFW.GLFW_KEY_TAB && getFocused() != null && getFocused() == terminal )
+        {
+            return getFocused().keyPressed( key, scancode, modifiers );
+        }
+
+        return super.keyPressed( key, scancode, modifiers );
+    }
+
+    @Override
+    public void render(MatrixStack transform, int mouseX, int mouseY, float partialTicks )
+    {
+        super.render( transform, mouseX, mouseY, partialTicks );
+
+        TextRenderer font = client.textRenderer;
+        List<OrderedText> lines = font.wrapLines( new TranslatableText( "gui.computercraft.pocket_computer_overlay" ), (int) (width * 0.8) );
+        float y = 10.0f;
+        for( OrderedText line : lines )
+        {
+            font.drawWithShadow( transform, line, (float) ((width / 2) - (client.textRenderer.getWidth( line ) / 2)), y, 0xFFFFFF );
+            y += 9.0f;
+        }
+    }
+}

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

@@ -0,0 +1,128 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.client.gui;
+
+import com.mojang.blaze3d.systems.RenderSystem;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.font.MultilineText;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.widget.ButtonWidget;
+import net.minecraft.client.gui.widget.ClickableWidget;
+import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.text.Text;
+import net.minecraft.util.Identifier;
+
+import javax.annotation.Nonnull;
+import java.util.List;
+
+public final class OptionScreen extends Screen
+{
+    private static final Identifier BACKGROUND = new Identifier( "computercraft", "textures/gui/blank_screen.png" );
+
+    public static final int BUTTON_WIDTH = 100;
+    public static final int BUTTON_HEIGHT = 20;
+
+    private static final int PADDING = 16;
+    private static final int FONT_HEIGHT = 9;
+
+    private int x;
+    private int y;
+    private int innerWidth;
+    private int innerHeight;
+
+    private MultilineText messageRenderer;
+    private final Text message;
+    private final List<ClickableWidget> buttons;
+    private final Runnable exit;
+
+    private final Screen originalScreen;
+
+    private OptionScreen(Text title, Text message, List<ClickableWidget> buttons, Runnable exit, Screen originalScreen )
+    {
+        super( title );
+        this.message = message;
+        this.buttons = buttons;
+        this.exit = exit;
+        this.originalScreen = originalScreen;
+    }
+
+    public static void show( MinecraftClient client, Text title, Text message, List<ClickableWidget> buttons, Runnable exit )
+    {
+        client.setScreen( new OptionScreen( title, message, buttons, exit, unwrap( client.currentScreen ) ) );
+    }
+
+    public static Screen unwrap( Screen screen )
+    {
+        return screen instanceof OptionScreen ? ((OptionScreen) screen).getOriginalScreen() : screen;
+    }
+
+    @Override
+    public void init()
+    {
+        super.init();
+
+        int buttonWidth = BUTTON_WIDTH * buttons.size() + PADDING * (buttons.size() - 1);
+        int innerWidth = this.innerWidth = Math.max( 256, buttonWidth + PADDING * 2 );
+
+        messageRenderer = MultilineText.create( textRenderer, message, innerWidth - PADDING * 2 );
+
+        int textHeight = messageRenderer.count() * FONT_HEIGHT + PADDING * 2;
+        innerHeight = textHeight + (buttons.isEmpty() ? 0 : buttons.get( 0 ).getHeight()) + PADDING;
+
+        x = (width - innerWidth) / 2;
+        y = (height - innerHeight) / 2;
+
+        int x = (width - buttonWidth) / 2;
+        for( ClickableWidget button : buttons )
+        {
+            button.x = x;
+            button.y = y + textHeight;
+            addDrawableChild( button );
+
+            x += BUTTON_WIDTH + PADDING;
+        }
+    }
+
+    @Override
+    public void render(@Nonnull MatrixStack transform, int mouseX, int mouseY, float partialTicks )
+    {
+        renderBackground( transform );
+
+        // Render the actual texture.
+        RenderSystem.setShaderTexture( 0, BACKGROUND );
+        drawTexture( transform, x, y, 0, 0, innerWidth, PADDING );
+        drawTexture( transform,
+            x, y + PADDING, 0, PADDING, innerWidth, innerHeight - PADDING * 2,
+            innerWidth, PADDING
+        );
+        drawTexture( transform, x, y + innerHeight - PADDING, 0, 256 - PADDING, innerWidth, PADDING );
+
+        messageRenderer.draw( transform, x + PADDING, y + PADDING, FONT_HEIGHT, 0x404040 );
+        super.render( transform, mouseX, mouseY, partialTicks );
+    }
+
+    @Override
+    public void onClose()
+    {
+        exit.run();
+    }
+
+    public static ClickableWidget newButton( Text component, ButtonWidget.PressAction clicked )
+    {
+        return new ButtonWidget( 0, 0, BUTTON_WIDTH, BUTTON_HEIGHT, component, clicked );
+    }
+
+    public void disable()
+    {
+        for( ClickableWidget widget : buttons ) widget.active = false;
+    }
+
+    @Nonnull
+    public Screen getOriginalScreen()
+    {
+        return originalScreen;
+    }
+}

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

@@ -34,7 +34,6 @@ import static dan200.computercraft.client.render.ComputerBorderRenderer.MARGIN;
 public class WidgetTerminal extends ClickableWidget {
     private static final float TERMINATE_TIME = 0.5f;
 
-//    private final MinecraftClient client;
     private final ClientComputer computer;
 
     // The positions of the actual terminal
@@ -43,8 +42,6 @@ public class WidgetTerminal extends ClickableWidget {
     private final int innerWidth;
     private final int innerHeight;
 
-    private final BitSet keysDown = new BitSet( 256 );
-//    private boolean focused;
     private float terminateTimer = -1;
     private float rebootTimer = -1;
     private float shutdownTimer = -1;
@@ -53,6 +50,8 @@ public class WidgetTerminal extends ClickableWidget {
     private int lastMouseX = -1;
     private int lastMouseY = -1;
 
+    private final BitSet keysDown = new BitSet( 256 );
+
     public WidgetTerminal( @Nonnull ClientComputer computer, int x, int y, int termWidth, int termHeight )
     {
         super( x, y, termWidth * FONT_WIDTH + MARGIN * 2, termHeight * FONT_HEIGHT + MARGIN * 2, LiteralText.EMPTY);
@@ -65,6 +64,18 @@ public class WidgetTerminal extends ClickableWidget {
         innerHeight = termHeight * FONT_HEIGHT;
     }
 
+    @Override
+    public boolean charTyped( char ch, int modifiers )
+    {
+        if( ch >= 32 && ch <= 126 || ch >= 160 && ch <= 255 ) // printable chars in byte range
+        {
+            // Queue the "char" event
+            queueEvent( "char", Character.toString( ch ));
+        }
+
+        return true;
+    }
+
     private boolean inTermRegion( double mouseX, double mouseY )
     {
         return active && visible && mouseX >= innerX && mouseY >= innerY && mouseX < innerX + innerWidth && mouseY < innerY + innerHeight;
@@ -79,10 +90,8 @@ public class WidgetTerminal extends ClickableWidget {
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            mouseX -= innerX;
+            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            mouseY -= innerY;
+            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            int charX = (int) (mouseX / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -105,10 +114,8 @@ public class WidgetTerminal extends ClickableWidget {
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            mouseX -= innerX;
+            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            mouseY -= innerY;
+            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            int charX = (int) (mouseX / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -134,10 +141,8 @@ public class WidgetTerminal extends ClickableWidget {
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            mouseX -= innerX;
+            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            mouseY -= innerY;
+            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            int charX = (int) (mouseX / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -161,10 +166,8 @@ public class WidgetTerminal extends ClickableWidget {
         Terminal term = computer.getTerminal();
         if( term != null )
         {
-            mouseX -= innerX;
+            int charX = (int) ((mouseX - innerX) / FONT_WIDTH);
-            mouseY -= innerY;
+            int charY = (int) ((mouseY - innerY) / FONT_HEIGHT);
-            int charX = (int) (mouseX / FONT_WIDTH);
-            int charY = (int) (mouseY / FONT_HEIGHT);
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
@@ -250,11 +253,7 @@ public class WidgetTerminal extends ClickableWidget {
             // Queue the "key" event and add to the down set
             boolean repeat = keysDown.get( key );
             keysDown.set( key );
-            IComputer computer = this.computer;
+            computer.keyDown( key, repeat );
-            if( computer != null )
-            {
-                computer.keyDown( key, repeat );
-            }
         }
 
         return true;
@@ -267,11 +266,7 @@ public class WidgetTerminal extends ClickableWidget {
         if( key >= 0 && keysDown.get( key ) )
         {
             keysDown.set( key, false );
-            IComputer computer = this.computer;
+            computer.keyUp( key );
-            if( computer != null )
-            {
-                computer.keyUp( key );
-            }
         }
 
         switch( key )
@@ -294,18 +289,6 @@ public class WidgetTerminal extends ClickableWidget {
         return true;
     }
 
-    @Override
-    public boolean charTyped( char ch, int modifiers )
-    {
-        if( ch >= 32 && ch <= 126 || ch >= 160 && ch <= 255 ) // printable chars in byte range
-        {
-            // Queue the "char" event
-            queueEvent( "char", Character.toString( ch ) );
-        }
-
-        return true;
-    }
-
     @Override
     public void onFocusedChanged( boolean focused )
     {
@@ -337,11 +320,7 @@ public class WidgetTerminal extends ClickableWidget {
 
     private void queueEvent( String event, Object... args )
     {
-        ClientComputer computer = this.computer;
+        computer.queueEvent( event, args );
-        if( computer != null )
-        {
-            computer.queueEvent( event, args );
-        }
     }
 
     public void update()
@@ -353,20 +332,12 @@ public class WidgetTerminal extends ClickableWidget {
 
         if( shutdownTimer >= 0 && shutdownTimer < TERMINATE_TIME && (shutdownTimer += 0.05f) > TERMINATE_TIME )
         {
-            ClientComputer computer = this.computer;
+            computer.shutdown();
-            if( computer != null )
-            {
-                computer.shutdown();
-            }
         }
 
         if( rebootTimer >= 0 && rebootTimer < TERMINATE_TIME && (rebootTimer += 0.05f) > TERMINATE_TIME )
         {
-            ClientComputer computer = this.computer;
+            computer.reboot();
-            if( computer != null )
-            {
-                computer.reboot();
-            }
         }
     }
 

src/main/java/dan200/computercraft/client/proxy/ComputerCraftProxyClient.java

@@ -20,12 +20,13 @@ import dan200.computercraft.shared.common.ContainerHeldItem;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.shared.computer.blocks.TileComputer;
-import dan200.computercraft.shared.computer.inventory.ContainerComputer;
+//import dan200.computercraft.shared.computer.inventory.ContainerComputer;
+import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
 import dan200.computercraft.shared.peripheral.diskdrive.ContainerDiskDrive;
 import dan200.computercraft.shared.peripheral.monitor.ClientMonitor;
 import dan200.computercraft.shared.peripheral.printer.ContainerPrinter;
-import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
+//import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.turtle.inventory.ContainerTurtle;
 import dan200.computercraft.shared.util.Config;
@@ -115,9 +116,11 @@ public final class ComputerCraftProxyClient implements ClientModInitializer
     // My IDE doesn't think so, but we do actually need these generics.
     private static void registerContainers()
     {
-        ScreenRegistry.<ContainerComputer, GuiComputer<ContainerComputer>>register( ComputerCraftRegistry.ModContainers.COMPUTER, GuiComputer::create );
+        ScreenRegistry.<ContainerComputerBase, GuiComputer<ContainerComputerBase>>register( ComputerCraftRegistry.ModContainers.COMPUTER, GuiComputer::create );
-        ScreenRegistry.<ContainerPocketComputer, GuiComputer<ContainerPocketComputer>>register( ComputerCraftRegistry.ModContainers.POCKET_COMPUTER,
+        ScreenRegistry.<ContainerComputerBase, GuiComputer<ContainerComputerBase>>register( ComputerCraftRegistry.ModContainers.POCKET_COMPUTER,
             GuiComputer::createPocket );
+        ScreenRegistry.<ContainerComputerBase, NoTermComputerScreen<ContainerComputerBase>>register( ComputerCraftRegistry.ModContainers.POCKET_COMPUTER_NO_TERM,
+            NoTermComputerScreen::new );
         ScreenRegistry.<ContainerTurtle, GuiTurtle>register( ComputerCraftRegistry.ModContainers.TURTLE, GuiTurtle::new );
 
         ScreenRegistry.<ContainerPrinter, GuiPrinter>register( ComputerCraftRegistry.ModContainers.PRINTER, GuiPrinter::new );

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

@@ -40,7 +40,7 @@ import java.util.List;
 import java.util.Random;
 
 public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
-{ //FIXME: more rendering puzzles.
+{
     private static final ModelIdentifier NORMAL_TURTLE_MODEL = new ModelIdentifier( "computercraft:turtle_normal", "inventory" );
     private static final ModelIdentifier ADVANCED_TURTLE_MODEL = new ModelIdentifier( "computercraft:turtle_advanced", "inventory" );
     private static final ModelIdentifier COLOUR_TURTLE_MODEL = new ModelIdentifier( "computercraft:turtle_colour", "inventory" );
@@ -48,13 +48,13 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
 
     private final Random random = new Random( 0 );
 
-    BlockEntityRenderDispatcher dispatcher;
+    BlockEntityRenderDispatcher renderer;
 
     public TileEntityTurtleRenderer( BlockEntityRendererFactory.Context context )
     {
-        dispatcher = context.getRenderDispatcher();
+        renderer = context.getRenderDispatcher();
     }
-    
+
     public static ModelIdentifier getTurtleModel( ComputerFamily family, boolean coloured )
     {
         switch( family )
@@ -80,6 +80,118 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
         return null;
     }
 
+    @Override
+    public void render( @Nonnull TileTurtle turtle, float partialTicks, @Nonnull MatrixStack transform, @Nonnull VertexConsumerProvider buffers,
+                        int lightmapCoord, int overlayLight )
+    {
+        // Render the label
+        String label = turtle.createProxy()
+            .getLabel();
+        HitResult hit = renderer.crosshairTarget;
+        if( label != null && hit.getType() == HitResult.Type.BLOCK && turtle.getPos()
+            .equals( ((BlockHitResult) hit).getBlockPos() ) )
+        {
+            MinecraftClient mc = MinecraftClient.getInstance();
+            TextRenderer font = mc.textRenderer;
+
+            transform.push();
+            transform.translate( 0.5, 1.2, 0.5 );
+            transform.multiply( mc.getEntityRenderDispatcher()
+                .getRotation() );
+            transform.scale( -0.025f, -0.025f, 0.025f );
+
+            Matrix4f matrix = transform.peek()
+                .getModel();
+            int opacity = (int) (mc.options.getTextBackgroundOpacity( 0.25f ) * 255) << 24;
+            float width = -font.getWidth( label ) / 2.0f;
+            font.draw( label, width, (float) 0, 0x20ffffff, false, matrix, buffers, true, opacity, lightmapCoord );
+            font.draw( label, width, (float) 0, 0xffffffff, false, matrix, buffers, false, 0, lightmapCoord );
+
+            transform.pop();
+        }
+
+        transform.push();
+
+        // Setup the transform.
+        Vec3d offset = turtle.getRenderOffset( partialTicks );
+        float yaw = turtle.getRenderYaw( partialTicks );
+        transform.translate( offset.x, offset.y, offset.z );
+
+        transform.translate( 0.5f, 0.5f, 0.5f );
+        transform.multiply( Vec3f.POSITIVE_Y.getDegreesQuaternion( 180.0f - yaw ) );
+        if( label != null && (label.equals( "Dinnerbone" ) || label.equals( "Grumm" )) )
+        {
+            // Flip the model
+            transform.scale( 1.0f, -1.0f, 1.0f );
+        }
+        transform.translate( -0.5f, -0.5f, -0.5f );
+
+        // Render the turtle
+        int colour = turtle.getColour();
+        ComputerFamily family = turtle.getFamily();
+        Identifier overlay = turtle.getOverlay();
+
+        VertexConsumer buffer = buffers.getBuffer( TexturedRenderLayers.getEntityTranslucentCull() );
+        renderModel( transform, buffer, lightmapCoord, overlayLight, getTurtleModel( family, colour != -1 ), colour == -1 ? null : new int[] { colour } );
+
+        // Render the overlay
+        ModelIdentifier overlayModel = getTurtleOverlayModel( overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS );
+        if( overlayModel != null )
+        {
+            renderModel( transform, buffer, lightmapCoord, overlayLight, overlayModel, null );
+        }
+
+        // Render the upgrades
+        renderUpgrade( transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.LEFT, partialTicks );
+        renderUpgrade( transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.RIGHT, partialTicks );
+
+        transform.pop();
+    }
+
+    public void renderUpgrade( @Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, TileTurtle turtle,
+                                      TurtleSide side, float f )
+    {
+        ITurtleUpgrade upgrade = turtle.getUpgrade( side );
+        if( upgrade == null )
+        {
+            return;
+        }
+        transform.push();
+
+        float toolAngle = turtle.getToolRenderAngle( side, f );
+        transform.translate( 0.0f, 0.5f, 0.5f );
+        transform.multiply( Vec3f.NEGATIVE_X.getDegreesQuaternion( toolAngle ) );
+        transform.translate( 0.0f, -0.5f, -0.5f );
+
+        TransformedModel model = upgrade.getModel( turtle.getAccess(), side );
+        model.push( transform );
+        renderModel( transform, renderer, lightmapCoord, overlayLight, model.getModel(), null );
+        transform.pop();
+
+        transform.pop();
+    }
+
+    public void renderModel( @Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight,
+                                    ModelIdentifier modelLocation, int[] tints )
+    {
+        BakedModelManager modelManager = MinecraftClient.getInstance()
+            .getItemRenderer()
+            .getModels()
+            .getModelManager();
+        renderModel( transform, renderer, lightmapCoord, overlayLight, modelManager.getModel( modelLocation ), tints );
+    }
+
+    public void renderModel( @Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, BakedModel model,
+                                    int[] tints )
+    {
+        random.setSeed( 0 );
+        renderQuads( transform, renderer, lightmapCoord, overlayLight, model.getQuads( null, null, random ), tints );
+        for( Direction facing : DirectionUtil.FACINGS )
+        {
+            renderQuads( transform, renderer, lightmapCoord, overlayLight, model.getQuads( null, facing, random ), tints );
+        }
+    }
+
     private static void renderQuads( @Nonnull MatrixStack transform, @Nonnull VertexConsumer buffer, int lightmapCoord, int overlayLight,
                                      List<BakedQuad> quads, int[] tints )
     {
@@ -111,117 +223,4 @@ public class TileEntityTurtleRenderer implements BlockEntityRenderer<TileTurtle>
                 true );
         }
     }
-
-    @Override
-    public void render( @Nonnull TileTurtle turtle, float partialTicks, @Nonnull MatrixStack transform, @Nonnull VertexConsumerProvider renderer,
-                        int lightmapCoord, int overlayLight )
-    {
-        // Render the label
-        String label = turtle.createProxy()
-            .getLabel();
-        MinecraftClient mc = MinecraftClient.getInstance();
-        HitResult hit = mc.crosshairTarget;
-        if( label != null && hit.getType() == HitResult.Type.BLOCK && turtle.getPos()
-            .equals( ((BlockHitResult) hit).getBlockPos() ) )
-        {
-            TextRenderer font = mc.textRenderer;
-
-            transform.push();
-            transform.translate( 0.5, 1.2, 0.5 );
-            transform.multiply( mc.getEntityRenderDispatcher()
-                .getRotation() );
-            transform.scale( -0.025f, -0.025f, 0.025f );
-
-            Matrix4f matrix = transform.peek()
-                .getModel();
-            int opacity = (int) (mc.options.getTextBackgroundOpacity( 0.25f ) * 255) << 24;
-            float width = -font.getWidth( label ) / 2.0f;
-            font.draw( label, width, (float) 0, 0x20ffffff, false, matrix, renderer, true, opacity, lightmapCoord );
-            font.draw( label, width, (float) 0, 0xffffffff, false, matrix, renderer, false, 0, lightmapCoord );
-
-            transform.pop();
-        }
-
-        transform.push();
-
-        // Setup the transform.
-        Vec3d offset = turtle.getRenderOffset( partialTicks );
-        float yaw = turtle.getRenderYaw( partialTicks );
-        transform.translate( offset.x, offset.y, offset.z );
-
-        transform.translate( 0.5f, 0.5f, 0.5f );
-        transform.multiply( Vec3f.POSITIVE_Y.getDegreesQuaternion( 180.0f - yaw ) );
-        if( label != null && (label.equals( "Dinnerbone" ) || label.equals( "Grumm" )) )
-        {
-            // Flip the model
-            transform.scale( 1.0f, -1.0f, 1.0f );
-        }
-        transform.translate( -0.5f, -0.5f, -0.5f );
-
-        // Render the turtle
-        int colour = turtle.getColour();
-        ComputerFamily family = turtle.getFamily();
-        Identifier overlay = turtle.getOverlay();
-
-        VertexConsumer buffer = renderer.getBuffer( TexturedRenderLayers.getEntityTranslucentCull() );
-        renderModel( transform, buffer, lightmapCoord, overlayLight, getTurtleModel( family, colour != -1 ), colour == -1 ? null : new int[] { colour } );
-
-        // Render the overlay
-        ModelIdentifier overlayModel = getTurtleOverlayModel( overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS );
-        if( overlayModel != null )
-        {
-            renderModel( transform, buffer, lightmapCoord, overlayLight, overlayModel, null );
-        }
-
-        // Render the upgrades
-        renderUpgrade( transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.LEFT, partialTicks );
-        renderUpgrade( transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.RIGHT, partialTicks );
-
-        transform.pop();
-    }
-
-    public static void renderUpgrade( @Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, TileTurtle turtle,
-                                      TurtleSide side, float f )
-    {
-        ITurtleUpgrade upgrade = turtle.getUpgrade( side );
-        if( upgrade == null )
-        {
-            return;
-        }
-        transform.push();
-
-        float toolAngle = turtle.getToolRenderAngle( side, f );
-        transform.translate( 0.0f, 0.5f, 0.5f );
-        transform.multiply( Vec3f.NEGATIVE_X.getDegreesQuaternion( toolAngle ) );
-        transform.translate( 0.0f, -0.5f, -0.5f );
-
-        TransformedModel model = upgrade.getModel( turtle.getAccess(), side );
-        model.push( transform );
-        TileEntityTurtleRenderer.renderModel( transform, renderer, lightmapCoord, overlayLight, model.getModel(), null );
-        transform.pop();
-
-        transform.pop();
-    }
-
-    public static void renderModel( @Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight,
-                                    ModelIdentifier modelLocation, int[] tints )
-    {
-        BakedModelManager modelManager = MinecraftClient.getInstance()
-            .getItemRenderer()
-            .getModels()
-            .getModelManager();
-        renderModel( transform, renderer, lightmapCoord, overlayLight, modelManager.getModel( modelLocation ), tints );
-    }
-
-    public static void renderModel( @Nonnull MatrixStack transform, @Nonnull VertexConsumer renderer, int lightmapCoord, int overlayLight, BakedModel model,
-                                    int[] tints )
-    {
-        Random random = new Random();
-        random.setSeed( 0 );
-        renderQuads( transform, renderer, lightmapCoord, overlayLight, model.getQuads( null, null, random ), tints );
-        for( Direction facing : DirectionUtil.FACINGS )
-        {
-            renderQuads( transform, renderer, lightmapCoord, overlayLight, model.getQuads( null, facing, random ), tints );
-        }
-    }
 }

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

@@ -293,9 +293,8 @@ class MountWrapper
 
     private FileSystemException localExceptionOf( @Nullable String localPath, @Nonnull IOException e )
     {
-        if( !location.isEmpty() && e instanceof FileOperationException )
+        if( !location.isEmpty() && e instanceof FileOperationException ex )
         {
-            FileOperationException ex = (FileOperationException) e;
             if( ex.getFilename() != null ) return localExceptionOf( ex.getFilename(), ex.getMessage() );
         }
 

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

@@ -13,10 +13,7 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.core.apis.handles.ArrayByteChannel;
 import dan200.computercraft.shared.util.IoUtil;
-import net.minecraft.resource.ReloadableResourceManager;
+import net.minecraft.resource.*;
-import net.minecraft.resource.Resource;
-import net.minecraft.resource.ResourceManager;
-import net.minecraft.resource.ResourceReloader;
 import net.minecraft.resource.ResourceReloader.Synchronizer;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.InvalidIdentifierException;
@@ -114,6 +111,7 @@ public final class ResourceMount implements IMount
             existingNamespace = file.getNamespace();
 
             if( !file.getNamespace().equals( namespace ) ) continue;
+            if( !FileSystem.contains( subPath, file.getPath() ) ) continue; // Some packs seem to include the parent?
 
             String localPath = FileSystem.toLocal( file.getPath(), subPath );
             create( newRoot, localPath );
@@ -300,7 +298,7 @@ public final class ResourceMount implements IMount
      * While people should really be keeping a permanent reference to this, some people construct it every
      * method call, so let's make this as small as possible.
      */
-    static class Listener implements ResourceReloader
+    static class Listener implements SynchronousResourceReloader
     {
         private static final Listener INSTANCE = new Listener();
 
@@ -308,19 +306,9 @@ public final class ResourceMount implements IMount
         private final Set<ReloadableResourceManager> managers = Collections.newSetFromMap( new WeakHashMap<>() );
 
         @Override
-        public CompletableFuture<Void> reload( Synchronizer synchronizer, ResourceManager manager, Profiler prepareProfiler, Profiler applyProfiler, Executor prepareExecutor, Executor applyExecutor )
+        public void reload( @Nonnull ResourceManager manager )
         {
-            return CompletableFuture.runAsync( () -> {
+            for( ResourceMount mount : mounts ) mount.load();
-                prepareProfiler.push( "Mount reloading" );
-                try
-                {
-                    for( ResourceMount mount : mounts ) mount.load();
-                }
-                finally
-                {
-                    prepareProfiler.pop();
-                }
-            }, prepareExecutor );
         }
 
         synchronized void add( ReloadableResourceManager manager, ResourceMount mount )

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

@@ -97,7 +97,7 @@ public class CobaltLuaMachine implements ILuaMachine
         globals.load( state, new CoroutineLib() );
         globals.load( state, new Bit32Lib() );
         globals.load( state, new Utf8Lib() );
-        if( ComputerCraft.debugEnable ) globals.load( state, new DebugLib() );
+        globals.load( state, new DebugLib() );
 
         // Remove globals we don't want to expose
         globals.rawset( "collectgarbage", Constants.NIL );
@@ -260,14 +260,12 @@ public class CobaltLuaMachine implements ILuaMachine
         if( object instanceof Number ) return valueOf( ((Number) object).doubleValue() );
         if( object instanceof Boolean ) return valueOf( (Boolean) object );
         if( object instanceof String ) return valueOf( object.toString() );
-        if( object instanceof byte[] )
+        if( object instanceof byte[] b )
         {
-            byte[] b = (byte[]) object;
             return valueOf( Arrays.copyOf( b, b.length ) );
         }
-        if( object instanceof ByteBuffer )
+        if( object instanceof ByteBuffer b )
         {
-            ByteBuffer b = (ByteBuffer) object;
             byte[] bytes = new byte[b.remaining()];
             b.get( bytes );
             return valueOf( bytes );
@@ -304,9 +302,8 @@ public class CobaltLuaMachine implements ILuaMachine
             return table;
         }
 
-        if( object instanceof Collection )
+        if( object instanceof Collection<?> objects )
         {
-            Collection<?> objects = (Collection<?>) object;
             LuaTable table = new LuaTable( objects.size(), 0 );
             values.put( object, table );
             int i = 0;
@@ -314,9 +311,8 @@ public class CobaltLuaMachine implements ILuaMachine
             return table;
         }
 
-        if( object instanceof Object[] )
+        if( object instanceof Object[] objects )
         {
-            Object[] objects = (Object[]) object;
             LuaTable table = new LuaTable( objects.length, 0 );
             values.put( object, table );
             for( int i = 0; i < objects.length; i++ ) table.rawset( i + 1, toValue( objects[i], values ) );
@@ -367,6 +363,7 @@ public class CobaltLuaMachine implements ILuaMachine
             case Constants.TSTRING:
                 return value.toString();
             case Constants.TTABLE:
+            {
                 // Table:
                 // Start remembering stuff
                 if( objects == null )
@@ -408,6 +405,7 @@ public class CobaltLuaMachine implements ILuaMachine
                     }
                 }
                 return table;
+            }
             default:
                 return null;
         }

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

@@ -9,6 +9,8 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.ILuaTask;
 import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.lua.MethodResult;
+import dan200.computercraft.core.asm.TaskCallback;
 import dan200.computercraft.core.computer.Computer;
 import dan200.computercraft.core.computer.MainThread;
 
@@ -66,4 +68,11 @@ class LuaContext implements ILuaContext
             throw new LuaException( "Task limit exceeded" );
         }
     }
+
+    @Nonnull
+    @Override
+    public MethodResult executeMainThreadTask( @Nonnull ILuaTask task ) throws LuaException
+    {
+        return TaskCallback.make( this, task );
+    }
 }

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

@@ -79,6 +79,7 @@ public class TextBuffer
         }
     }
 
+    @Override
     public String toString()
     {
         return new String( text );

src/main/java/dan200/computercraft/shared/BundledRedstone.java

@@ -14,25 +14,24 @@ import net.minecraft.util.math.Direction;
 import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
-import java.util.LinkedHashSet;
+import java.util.ArrayList;
 import java.util.Objects;
-import java.util.Set;
 
 public final class BundledRedstone
 {
-    private static final Set<IBundledRedstoneProvider> providers = new LinkedHashSet<>();
+    private static final ArrayList<IBundledRedstoneProvider> providers = new ArrayList<>();
 
     private BundledRedstone() {}
 
     public static synchronized void register( @Nonnull IBundledRedstoneProvider provider )
     {
         Objects.requireNonNull( provider, "provider cannot be null" );
-        providers.add( provider );
+        if( !providers.contains( provider ) ) providers.add( provider );
     }
 
     public static int getDefaultOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side )
     {
-        return !world.isInBuildLimit( pos ) ? DefaultBundledRedstoneProvider.getDefaultBundledRedstoneOutput( world, pos, side ) : -1;
+        return world.isInBuildLimit( pos ) ? DefaultBundledRedstoneProvider.getDefaultBundledRedstoneOutput( world, pos, side ) : -1;
     }
 
     public static int getOutput( World world, BlockPos pos, Direction side )

src/main/java/dan200/computercraft/shared/ComputerCraftRegistry.java

@@ -13,12 +13,17 @@ import dan200.computercraft.shared.computer.blocks.BlockComputer;
 import dan200.computercraft.shared.computer.blocks.TileCommandComputer;
 import dan200.computercraft.shared.computer.blocks.TileComputer;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
-import dan200.computercraft.shared.computer.inventory.ContainerComputer;
+import dan200.computercraft.shared.computer.inventory.ComputerMenuWithoutInventory;
+import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
 import dan200.computercraft.shared.computer.items.ItemComputer;
 import dan200.computercraft.shared.media.items.ItemDisk;
 import dan200.computercraft.shared.media.items.ItemPrintout;
 import dan200.computercraft.shared.media.items.ItemTreasureDisk;
+import dan200.computercraft.shared.network.container.ComputerContainerData;
+import dan200.computercraft.shared.network.container.ContainerData;
+import dan200.computercraft.shared.network.container.HeldItemContainerData;
+import dan200.computercraft.shared.network.container.ViewComputerContainerData;
 import dan200.computercraft.shared.peripheral.diskdrive.BlockDiskDrive;
 import dan200.computercraft.shared.peripheral.diskdrive.ContainerDiskDrive;
 import dan200.computercraft.shared.peripheral.diskdrive.TileDiskDrive;
@@ -32,7 +37,6 @@ import dan200.computercraft.shared.peripheral.printer.ContainerPrinter;
 import dan200.computercraft.shared.peripheral.printer.TilePrinter;
 import dan200.computercraft.shared.peripheral.speaker.BlockSpeaker;
 import dan200.computercraft.shared.peripheral.speaker.TileSpeaker;
-import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.pocket.peripherals.PocketModem;
 import dan200.computercraft.shared.pocket.peripherals.PocketSpeaker;
@@ -42,10 +46,8 @@ import dan200.computercraft.shared.turtle.core.TurtlePlayer;
 import dan200.computercraft.shared.turtle.inventory.ContainerTurtle;
 import dan200.computercraft.shared.turtle.items.ItemTurtle;
 import dan200.computercraft.shared.turtle.upgrades.*;
-//import dan200.computercraft.shared.util.FixedPointTileEntityType;
-import net.fabricmc.fabric.api.object.builder.v1.block.entity.FabricBlockEntityTypeBuilder;
-import net.fabricmc.fabric.api.object.builder.v1.block.entity.FabricBlockEntityTypeBuilder.Factory;
 import net.fabricmc.fabric.api.object.builder.v1.block.FabricBlockSettings;
+import net.fabricmc.fabric.api.object.builder.v1.block.entity.FabricBlockEntityTypeBuilder;
 import net.fabricmc.fabric.api.screenhandler.v1.ScreenHandlerRegistry;
 import net.minecraft.block.*;
 import net.minecraft.block.entity.BlockEntity;
@@ -63,10 +65,7 @@ import net.minecraft.util.Identifier;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.registry.Registry;
 
-import java.util.Objects;
 import java.util.function.BiFunction;
-import java.util.function.Function;
-import java.util.function.Supplier;
 
 import static net.minecraft.util.registry.Registry.BLOCK_ENTITY_TYPE;
 
@@ -258,24 +257,20 @@ public final class ComputerCraftRegistry
 
     public static class ModContainers
     {
-        public static final ScreenHandlerType<ContainerComputer> COMPUTER = registerExtended( "computer", ContainerComputer::new );
+        public static final ScreenHandlerType<ContainerComputerBase> COMPUTER = ContainerData.toType(new Identifier( MOD_ID, "computer" ), ModContainers.COMPUTER, ComputerContainerData::new, ComputerMenuWithoutInventory::new );
-        public static final ScreenHandlerType<ContainerPocketComputer> POCKET_COMPUTER = registerExtended( "pocket_computer", ContainerPocketComputer::new );
+        public static final ScreenHandlerType<ContainerComputerBase> POCKET_COMPUTER = ContainerData.toType( new Identifier( MOD_ID, "pocket_computer" ), ModContainers.POCKET_COMPUTER, ComputerContainerData::new, ComputerMenuWithoutInventory::new );
-        public static final ScreenHandlerType<ContainerTurtle> TURTLE = registerExtended( "turtle", ContainerTurtle::new );
+        public static final ScreenHandlerType<ContainerComputerBase> POCKET_COMPUTER_NO_TERM = ContainerData.toType( new Identifier( MOD_ID, "pocket_computer_no_term" ), ModContainers.POCKET_COMPUTER_NO_TERM, ComputerContainerData::new, ComputerMenuWithoutInventory::new );
+        public static final ScreenHandlerType<ContainerTurtle> TURTLE = ContainerData.toType( new Identifier( MOD_ID, "turtle" ), ComputerContainerData::new, ContainerTurtle::new );
         public static final ScreenHandlerType<ContainerDiskDrive> DISK_DRIVE = registerSimple( "disk_drive", ContainerDiskDrive::new );
         public static final ScreenHandlerType<ContainerPrinter> PRINTER = registerSimple( "printer", ContainerPrinter::new );
-        public static final ScreenHandlerType<ContainerHeldItem> PRINTOUT = registerExtended( "printout", ContainerHeldItem::createPrintout );
+        public static final ScreenHandlerType<ContainerHeldItem> PRINTOUT = ContainerData.toType( new Identifier( MOD_ID, "printout" ), HeldItemContainerData::new, ContainerHeldItem::createPrintout );
-        public static final ScreenHandlerType<ContainerViewComputer> VIEW_COMPUTER = registerExtended( "view_computer", ContainerViewComputer::new );
+        public static final ScreenHandlerType<ContainerViewComputer> VIEW_COMPUTER = ContainerData.toType( new Identifier( MOD_ID, "view_computer" ), ViewComputerContainerData::new, ContainerViewComputer::new );
 
         private static <T extends ScreenHandler> ScreenHandlerType<T> registerSimple( String id,
                                                                                       ScreenHandlerRegistry.SimpleClientHandlerFactory<T> function )
         {
             return ScreenHandlerRegistry.registerSimple( new Identifier( MOD_ID, id ), function );
         }
-
-        private static <T extends ScreenHandler> ScreenHandlerType<T> registerExtended( String id, ScreenHandlerRegistry.ExtendedClientHandlerFactory<T> function )
-        {
-            return ScreenHandlerRegistry.registerExtended( new Identifier( MOD_ID, id ), function );
-        }
     }
 
     public static final class TurtleUpgrades

src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java

@@ -245,7 +245,7 @@ public final class CommandComputerCraft
                         @Override
                         public ScreenHandler createMenu( int id, @Nonnull PlayerInventory player, @Nonnull PlayerEntity entity )
                         {
-                            return new ContainerViewComputer( id, computer );
+                            return new ContainerViewComputer( id, player, computer );
                         }
                     } );
                     return 1;

src/main/java/dan200/computercraft/shared/command/UserLevel.java

@@ -56,18 +56,17 @@ public enum UserLevel implements Predicate<ServerCommandSource>
     public boolean test( ServerCommandSource source )
     {
         if( this == ANYONE ) return true;
-
+        if( this == OWNER ) return isOwner( source );
-        if( this == OWNER || this == OWNER_OP )
+        if( this == OWNER_OP && isOwner( source ) ) return true;
-        {
-            MinecraftServer server = source.getServer();
-            Entity sender = source.getEntity();
-            if( server.isSingleplayer() && sender instanceof PlayerEntity &&
-                ((PlayerEntity) sender).getGameProfile().getName().equalsIgnoreCase( server.getServerModName() ) )
-            {
-                return true;
-            }
-        }
-
         return source.hasPermissionLevel( toLevel() );
     }
+
+    private static boolean isOwner( ServerCommandSource source )
+    {
+        MinecraftServer server = source.getServer();
+        Entity sender = source.getEntity();
+        return server.isDedicated()
+            ? source.getEntity() == null && source.hasPermissionLevel( 4 ) && source.getName().equals( "Server" )
+            : sender instanceof PlayerEntity && ((PlayerEntity) sender).getGameProfile().getName().equalsIgnoreCase( server.getServerModName() );
+    }
 }

src/main/java/dan200/computercraft/shared/common/ClientTerminal.java

@@ -79,19 +79,4 @@ public class ClientTerminal implements ITerminal
             terminalChanged = true;
         }
     }
-
-    public void readDescription( NbtCompound nbt )
-    {
-        colour = nbt.getBoolean( "colour" );
-        if( nbt.contains( "terminal" ) )
-        {
-        	NbtCompound terminal = nbt.getCompound( "terminal" );
-            resizeTerminal( terminal.getInt( "term_width" ), terminal.getInt( "term_height" ) );
-            this.terminal.readFromNBT( terminal );
-        }
-        else
-        {
-            deleteTerminal();
-        }
-    }
 }

src/main/java/dan200/computercraft/shared/common/ContainerHeldItem.java

@@ -36,11 +36,6 @@ public class ContainerHeldItem extends ScreenHandler
             .copy();
     }
 
-    public static ContainerHeldItem createPrintout( int id, PlayerInventory inventory, PacketByteBuf data )
-    {
-        return createPrintout( id, inventory, new HeldItemContainerData( data ) );
-    }
-
     public static ContainerHeldItem createPrintout( int id, PlayerInventory inventory, HeldItemContainerData data )
     {
         return new ContainerHeldItem( ComputerCraftRegistry.ModContainers.PRINTOUT, id, inventory.player, data.getHand() );

src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java

@@ -8,10 +8,11 @@ package dan200.computercraft.shared.computer.blocks;
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.core.computer.ComputerSide;
+import dan200.computercraft.shared.ComputerCraftRegistry;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ComputerState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
-import dan200.computercraft.shared.computer.inventory.ContainerComputer;
+import dan200.computercraft.shared.computer.inventory.ComputerMenuWithoutInventory;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.entity.BlockEntityType;
 import net.minecraft.entity.player.PlayerEntity;
@@ -104,7 +105,7 @@ public class TileComputer extends TileComputerBase
     @Override
     public ScreenHandler createMenu( int id, @Nonnull PlayerInventory inventory, @Nonnull PlayerEntity player )
     {
-        return new ContainerComputer( id, this );
+        return new ComputerMenuWithoutInventory( ComputerCraftRegistry.ModContainers.COMPUTER, id, inventory, this::isUsableByPlayer, createServerComputer(), getFamily() );
     }
 
 }

src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java

@@ -17,7 +17,6 @@ import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ComputerState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
 import dan200.computercraft.shared.network.container.ComputerContainerData;
-import dan200.computercraft.shared.peripheral.diskdrive.TileDiskDrive;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.RedstoneUtil;
 import joptsimple.internal.Strings;

src/main/java/dan200/computercraft/shared/computer/core/ComputerState.java

@@ -12,13 +12,15 @@ import javax.annotation.Nonnull;
 
 public enum ComputerState implements StringIdentifiable
 {
-    OFF( "off" ), ON( "on" ), BLINKING( "blinking" );
+    OFF( "off", "" ), ON( "on", "_on" ), BLINKING( "blinking", "_blink" );
 
     private final String name;
+    private final String texture;
 
-    ComputerState( String name )
+    ComputerState( String name, String texture )
     {
         this.name = name;
+        this.texture = texture;
     }
 
     @Nonnull
@@ -33,4 +35,10 @@ public enum ComputerState implements StringIdentifiable
     {
         return name;
     }
+
+    @Nonnull
+    public String getTexture()
+    {
+        return texture;
+    }
 }

src/main/java/dan200/computercraft/shared/computer/core/IContainerComputer.java

@@ -6,13 +6,19 @@
 
 package dan200.computercraft.shared.computer.core;
 
+import dan200.computercraft.shared.computer.upload.FileSlice;
+import dan200.computercraft.shared.computer.upload.FileUpload;
+import net.minecraft.server.network.ServerPlayerEntity;
+
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.List;
+import java.util.UUID;
 
 /**
  * An instance of {@link Container} which provides a computer. You should implement this if you provide custom computers/GUIs to interact with them.
  */
-@FunctionalInterface
+//@FunctionalInterface
 public interface IContainerComputer
 {
     /**
@@ -31,8 +37,37 @@ public interface IContainerComputer
      * @return This container's input.
      */
     @Nonnull
-    default InputState getInput()
+    InputState getInput();
-    {
+
-        return new InputState( this );
+    /**
-    }
+     * Start a file upload into this container.
+     *
+     * @param uploadId The unique ID of this upload.
+     * @param files    The files to upload.
+     */
+    void startUpload(@Nonnull UUID uploadId, @Nonnull List<FileUpload> files );
+
+    /**
+     * Append more data to partially uploaded files.
+     *
+     * @param uploadId The unique ID of this upload.
+     * @param slices   Additional parts of file data to upload.
+     */
+    void continueUpload( @Nonnull UUID uploadId, @Nonnull List<FileSlice> slices );
+
+    /**
+     * Finish off an upload. This either writes the uploaded files or
+     *
+     * @param uploader The player uploading files.
+     * @param uploadId The unique ID of this upload.
+     */
+    void finishUpload(@Nonnull ServerPlayerEntity uploader, @Nonnull UUID uploadId );
+
+    /**
+     * Continue an upload.
+     *
+     * @param uploader  The player uploading files.
+     * @param overwrite Whether the files should be overwritten or not.
+     */
+    void confirmUpload( @Nonnull ServerPlayerEntity uploader, boolean overwrite );
 }

src/main/java/dan200/computercraft/shared/computer/inventory/ComputerMenuWithoutInventory.java

@@ -0,0 +1,41 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.computer.inventory;
+
+import dan200.computercraft.shared.computer.core.ComputerFamily;
+import dan200.computercraft.shared.computer.core.IComputer;
+import dan200.computercraft.shared.network.container.ComputerContainerData;
+import dan200.computercraft.shared.util.InvisibleSlot;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.screen.ScreenHandlerType;
+
+import java.util.function.Predicate;
+
+/**
+ * A computer menu which does not have any visible inventory.
+ *
+ * This adds invisible versions of the player's hotbars slots, to ensure they're synced to the client when changed.
+ */
+public class ComputerMenuWithoutInventory extends ContainerComputerBase
+{
+    public ComputerMenuWithoutInventory(ScreenHandlerType<? extends ContainerComputerBase> type, int id, PlayerInventory player, Predicate<PlayerEntity> canUse, IComputer computer, ComputerFamily family )
+    {
+        super( type, id, canUse, computer, family );
+        addSlots( player );
+    }
+
+    public ComputerMenuWithoutInventory( ScreenHandlerType<? extends ContainerComputerBase> type, int id, PlayerInventory player, ComputerContainerData data )
+    {
+        super( type, id, player, data );
+        addSlots( player );
+    }
+
+    private void addSlots( PlayerInventory player )
+    {
+        for( int i = 0; i < 9; i++ ) addSlot( new InvisibleSlot( player, i ) );
+    }
+}

src/main/java/dan200/computercraft/shared/computer/inventory/ContainerComputer.java

@@ -1,25 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.shared.computer.inventory;
-
-import dan200.computercraft.shared.ComputerCraftRegistry;
-import dan200.computercraft.shared.computer.blocks.TileComputer;
-import net.minecraft.entity.player.PlayerInventory;
-import net.minecraft.network.PacketByteBuf;
-
-public class ContainerComputer extends ContainerComputerBase
-{
-    public ContainerComputer( int id, TileComputer tile )
-    {
-        super( ComputerCraftRegistry.ModContainers.COMPUTER, id, tile::isUsableByPlayer, tile.createServerComputer(), tile.getFamily() );
-    }
-
-    public ContainerComputer( int i, PlayerInventory playerInventory, PacketByteBuf packetByteBuf )
-    {
-        super( ComputerCraftRegistry.ModContainers.COMPUTER, i, playerInventory, packetByteBuf );
-    }
-}

src/main/java/dan200/computercraft/shared/computer/inventory/ContainerComputerBase.java

@@ -7,36 +7,54 @@
 package dan200.computercraft.shared.computer.inventory;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.core.filesystem.FileSystem;
+import dan200.computercraft.core.filesystem.FileSystemException;
+import dan200.computercraft.core.filesystem.FileSystemWrapper;
 import dan200.computercraft.shared.computer.core.*;
+import dan200.computercraft.shared.computer.upload.FileSlice;
+import dan200.computercraft.shared.computer.upload.FileUpload;
+import dan200.computercraft.shared.computer.upload.UploadResult;
+import dan200.computercraft.shared.network.NetworkHandler;
+import dan200.computercraft.shared.network.client.UploadResultMessage;
 import dan200.computercraft.shared.network.container.ComputerContainerData;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.network.PacketByteBuf;
 import net.minecraft.screen.ScreenHandler;
 import net.minecraft.screen.ScreenHandlerType;
+import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.text.TranslatableText;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Objects;
+import java.io.IOException;
+import java.nio.channels.WritableByteChannel;
+import java.util.*;
+import java.util.function.Function;
 import java.util.function.Predicate;
 
-public class ContainerComputerBase extends ScreenHandler implements IContainerComputer
+public abstract class ContainerComputerBase extends ScreenHandler implements IContainerComputer
 {
+    private static final String LIST_PREFIX = "\n \u2022 ";
+
     private final Predicate<PlayerEntity> canUse;
     private final IComputer computer;
     private final ComputerFamily family;
     private final InputState input = new InputState( this );
 
-    protected ContainerComputerBase( ScreenHandlerType<? extends ContainerComputerBase> type, int id, PlayerInventory player, PacketByteBuf packetByteBuf )
+    private UUID toUploadId;
+    private List<FileUpload> toUpload;
+
+    public ContainerComputerBase( ScreenHandlerType<? extends ContainerComputerBase> type, int id, PlayerInventory player, ComputerContainerData data )
     {
         this( type,
             id,
             x -> true,
-            getComputer( player, new ComputerContainerData( new PacketByteBuf( packetByteBuf.copy() ) ) ),
+            getComputer( player, data ),
-            new ComputerContainerData( new PacketByteBuf( packetByteBuf.copy() ) ).getFamily() );
+            data.getFamily() );
     }
 
-    protected ContainerComputerBase( ScreenHandlerType<? extends ContainerComputerBase> type, int id, Predicate<PlayerEntity> canUse, IComputer computer,
+    public ContainerComputerBase( ScreenHandlerType<? extends ContainerComputerBase> type, int id, Predicate<PlayerEntity> canUse, IComputer computer,
                                      ComputerFamily family )
     {
         super( type, id );
@@ -93,4 +111,121 @@ public class ContainerComputerBase extends ScreenHandler implements IContainerCo
     {
         return canUse.test( player );
     }
+
+    @Override
+    public void startUpload(@Nonnull UUID uuid, @Nonnull List<FileUpload> files )
+    {
+        toUploadId = uuid;
+        toUpload = files;
+    }
+
+    @Override
+    public void continueUpload( @Nonnull UUID uploadId, @Nonnull List<FileSlice> slices )
+    {
+        if( toUploadId == null || toUpload == null || !toUploadId.equals( uploadId ) )
+        {
+            ComputerCraft.log.warn( "Invalid continueUpload call, skipping." );
+            return;
+        }
+
+        for( FileSlice slice : slices ) slice.apply( toUpload );
+    }
+
+    @Override
+    public void finishUpload(@Nonnull ServerPlayerEntity uploader, @Nonnull UUID uploadId )
+    {
+        if( toUploadId == null || toUpload == null || toUpload.isEmpty() || !toUploadId.equals( uploadId ) )
+        {
+            ComputerCraft.log.warn( "Invalid finishUpload call, skipping." );
+            return;
+        }
+
+        UploadResultMessage message = finishUpload( false );
+        NetworkHandler.sendToPlayer( uploader, message );
+    }
+
+    @Override
+    public void confirmUpload( @Nonnull ServerPlayerEntity uploader, boolean overwrite )
+    {
+        if( toUploadId == null || toUpload == null || toUpload.isEmpty() )
+        {
+            ComputerCraft.log.warn( "Invalid finishUpload call, skipping." );
+            return;
+        }
+
+        UploadResultMessage message = finishUpload( true );
+        NetworkHandler.sendToPlayer( uploader, message );
+    }
+
+    @Nonnull
+    private UploadResultMessage finishUpload( boolean forceOverwrite )
+    {
+        ServerComputer computer = (ServerComputer) getComputer();
+        if( computer == null ) return UploadResultMessage.COMPUTER_OFF;
+
+        FileSystem fs = computer.getComputer().getEnvironment().getFileSystem();
+        if( fs == null ) return UploadResultMessage.COMPUTER_OFF;
+
+        for( FileUpload upload : toUpload )
+        {
+            if( !upload.checksumMatches() )
+            {
+                ComputerCraft.log.warn( "Checksum failed to match for {}.", upload.getName() );
+                return new UploadResultMessage( UploadResult.ERROR, new TranslatableText( "gui.computercraft.upload.failed.corrupted" ) );
+            }
+        }
+
+        try
+        {
+            List<String> overwrite = new ArrayList<>();
+            List<FileUpload> files = toUpload;
+            toUpload = null;
+            for( FileUpload upload : files )
+            {
+                if( !fs.exists( upload.getName() ) ) continue;
+                if( fs.isDir( upload.getName() ) )
+                {
+                    return new UploadResultMessage(
+                        UploadResult.ERROR,
+                        new TranslatableText( "gui.computercraft.upload.failed.overwrite_dir", upload.getName() )
+                    );
+                }
+
+                overwrite.add( upload.getName() );
+            }
+
+            if( !overwrite.isEmpty() && !forceOverwrite )
+            {
+                StringJoiner joiner = new StringJoiner( LIST_PREFIX, LIST_PREFIX, "" );
+                for( String value : overwrite ) joiner.add( value );
+                toUpload = files;
+                return new UploadResultMessage(
+                    UploadResult.CONFIRM_OVERWRITE,
+                    new TranslatableText( "gui.computercraft.upload.overwrite.detail", joiner.toString() )
+                );
+            }
+
+            long availableSpace = fs.getFreeSpace( "/" );
+            long neededSpace = 0;
+            for( FileUpload upload : files ) neededSpace += Math.max( 512, upload.getBytes().remaining() );
+            if( neededSpace > availableSpace ) return UploadResultMessage.OUT_OF_SPACE;
+
+            for( FileUpload file : files )
+            {
+                try( FileSystemWrapper<WritableByteChannel> channel = fs.openForWrite( file.getName(), false, Function.identity() ) )
+                {
+                    channel.get().write( file.getBytes() );
+                }
+            }
+
+            return new UploadResultMessage(
+                UploadResult.SUCCESS, new TranslatableText( "gui.computercraft.upload.success.msg", files.size() )
+            );
+        }
+        catch( FileSystemException | IOException e )
+        {
+            ComputerCraft.log.error( "Error uploading files", e );
+            return new UploadResultMessage( UploadResult.ERROR, new TranslatableText( "gui.computercraft.upload.failed.generic", e.getMessage() ) );
+        }
+    }
 }

src/main/java/dan200/computercraft/shared/computer/inventory/ContainerViewComputer.java

@@ -18,21 +18,20 @@ import net.minecraft.network.PacketByteBuf;
 
 import javax.annotation.Nonnull;
 
-public class ContainerViewComputer extends ContainerComputerBase
+public class ContainerViewComputer extends ComputerMenuWithoutInventory
 {
     private final int width;
     private final int height;
 
-    public ContainerViewComputer( int id, ServerComputer computer )
+    public ContainerViewComputer( int id, PlayerInventory player, ServerComputer computer )
     {
-        super( ComputerCraftRegistry.ModContainers.VIEW_COMPUTER, id, player -> canInteractWith( computer, player ), computer, computer.getFamily() );
+        super( ComputerCraftRegistry.ModContainers.VIEW_COMPUTER, id, player, p -> canInteractWith( computer, p ), computer, computer.getFamily() );
         width = height = 0;
     }
 
-    public ContainerViewComputer( int id, PlayerInventory player, PacketByteBuf packetByteBuf )
+    public ContainerViewComputer( int id, PlayerInventory player, ViewComputerContainerData data )
     {
-        super( ComputerCraftRegistry.ModContainers.VIEW_COMPUTER, id, player, packetByteBuf );
+        super( ComputerCraftRegistry.ModContainers.VIEW_COMPUTER, id, player, data );
-        ViewComputerContainerData data = new ViewComputerContainerData( new PacketByteBuf( packetByteBuf.copy() ) );
         width = data.getWidth();
         height = data.getHeight();
     }

src/main/java/dan200/computercraft/shared/computer/upload/FileSlice.java

@@ -0,0 +1,63 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.computer.upload;
+
+import dan200.computercraft.ComputerCraft;
+
+import java.nio.ByteBuffer;
+import java.util.List;
+
+public class FileSlice
+{
+    private final int fileId;
+    private final int offset;
+    private final ByteBuffer bytes;
+
+    public FileSlice( int fileId, int offset, ByteBuffer bytes )
+    {
+        this.fileId = fileId;
+        this.offset = offset;
+        this.bytes = bytes;
+    }
+
+    public int getFileId()
+    {
+        return fileId;
+    }
+
+    public int getOffset()
+    {
+        return offset;
+    }
+
+    public ByteBuffer getBytes()
+    {
+        return bytes;
+    }
+
+    public void apply( List<FileUpload> files )
+    {
+        if( fileId < 0 || fileId >= files.size() )
+        {
+            ComputerCraft.log.warn( "File ID is out-of-bounds (0 <= {} < {})", fileId, files.size() );
+            return;
+        }
+
+        ByteBuffer file = files.get( fileId ).getBytes();
+        if( offset < 0 || offset + bytes.remaining() > file.capacity() )
+        {
+            ComputerCraft.log.warn( "File offset is out-of-bounds (0 <= {} <= {})", offset, file.capacity() - offset );
+            return;
+        }
+
+        bytes.rewind();
+        file.position( offset );
+        file.put( bytes );
+        file.rewind();
+
+        if( bytes.remaining() != 0 ) throw new IllegalStateException( "Should have read the whole buffer" );
+    }
+}

src/main/java/dan200/computercraft/shared/computer/upload/FileUpload.java

@@ -0,0 +1,80 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.computer.upload;
+
+import dan200.computercraft.ComputerCraft;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.nio.ByteBuffer;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+
+public class FileUpload
+{
+    public static final int CHECKSUM_LENGTH = 32;
+
+    private final String name;
+    private final int length;
+    private final ByteBuffer bytes;
+    private final byte[] checksum;
+
+    public FileUpload( String name, ByteBuffer bytes, byte[] checksum )
+    {
+        this.name = name;
+        this.bytes = bytes;
+        length = bytes.remaining();
+        this.checksum = checksum;
+    }
+
+    @Nonnull
+    public String getName()
+    {
+        return name;
+    }
+
+    @Nonnull
+    public ByteBuffer getBytes()
+    {
+        return bytes;
+    }
+
+    public int getLength()
+    {
+        return length;
+    }
+
+    @Nonnull
+    public byte[] getChecksum()
+    {
+        return checksum;
+    }
+
+    public boolean checksumMatches()
+    {
+        // This is meant to be a checksum. Doesn't need to be cryptographically secure, hence non constant time.
+        byte[] digest = getDigest( bytes );
+        return digest != null && Arrays.equals( checksum, digest );
+    }
+
+    @Nullable
+    public static byte[] getDigest( ByteBuffer bytes )
+    {
+        try
+        {
+            bytes.rewind();
+            MessageDigest digest = MessageDigest.getInstance( "SHA-256" );
+            digest.update( bytes );
+            return digest.digest();
+        }
+        catch( NoSuchAlgorithmException e )
+        {
+            ComputerCraft.log.warn( "Failed to compute digest ({})", e.toString() );
+            return null;
+        }
+    }
+}

src/main/java/dan200/computercraft/shared/computer/upload/UploadResult.java

@@ -0,0 +1,25 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.computer.upload;
+
+import net.minecraft.text.Text;
+import net.minecraft.text.TranslatableText;
+
+public enum UploadResult
+{
+    SUCCESS,
+    ERROR,
+    CONFIRM_OVERWRITE;
+
+    public static final Text SUCCESS_TITLE = new TranslatableText( "gui.computercraft.upload.success" );
+
+    public static final Text FAILED_TITLE = new TranslatableText( "gui.computercraft.upload.failed" );
+    public static final Text COMPUTER_OFF_MSG = new TranslatableText( "gui.computercraft.upload.failed.computer_off" );
+    public static final Text OUT_OF_SPACE_MSG = new TranslatableText( "gui.computercraft.upload.failed.out_of_space" );
+    public static final Text TOO_MUCH_MSG = new TranslatableText( "gui.computercraft.upload.failed.too_much" );
+
+    public static final Text UPLOAD_OVERWRITE = new TranslatableText( "gui.computercraft.upload.overwrite" );
+}

src/main/java/dan200/computercraft/shared/network/NetworkHandler.java

@@ -56,18 +56,21 @@ public final class NetworkHandler
         }
 
         // Server messages
-        registerMainThread( 0, ComputerActionServerMessage::new );
+        registerMainThread( 0, ComputerActionServerMessage.class, ComputerActionServerMessage::new );
-        registerMainThread( 1, QueueEventServerMessage::new );
+        registerMainThread( 1, QueueEventServerMessage.class, QueueEventServerMessage::new );
-        registerMainThread( 2, RequestComputerMessage::new );
+        registerMainThread( 2, RequestComputerMessage.class, RequestComputerMessage::new );
-        registerMainThread( 3, KeyEventServerMessage::new );
+        registerMainThread( 3, KeyEventServerMessage.class, KeyEventServerMessage::new );
-        registerMainThread( 4, MouseEventServerMessage::new );
+        registerMainThread( 4, MouseEventServerMessage.class, MouseEventServerMessage::new );
+        registerMainThread( 5, UploadFileMessage.class, UploadFileMessage::new );
+        registerMainThread( 6, ContinueUploadMessage.class, ContinueUploadMessage::new );
 
         // Client messages
-        registerMainThread( 10, ChatTableClientMessage::new );
+        registerMainThread( 10, ChatTableClientMessage.class, ChatTableClientMessage::new );
-        registerMainThread( 11, ComputerDataClientMessage::new );
+        registerMainThread( 11, ComputerDataClientMessage.class, ComputerDataClientMessage::new );
-        registerMainThread( 12, ComputerDeletedClientMessage::new );
+        registerMainThread( 12, ComputerDeletedClientMessage.class, ComputerDeletedClientMessage::new );
-        registerMainThread( 13, ComputerTerminalClientMessage::new );
+        registerMainThread( 13, ComputerTerminalClientMessage.class, ComputerTerminalClientMessage::new );
         registerMainThread( 14, PlayRecordClientMessage.class, PlayRecordClientMessage::new );
+        registerMainThread( 19, UploadResultMessage.class, UploadResultMessage::new );
     }
 
     private static void receive( PacketContext context, PacketByteBuf buffer )
@@ -77,22 +80,6 @@ public final class NetworkHandler
             .accept( context, buffer );
     }
 
-    /**
-     * /** Register packet, and a thread-unsafe handler for it.
-     *
-     * @param <T>     The type of the packet to send.
-     * @param id      The identifier for this packet type
-     * @param factory The factory for this type of packet.
-     */
-    private static <T extends NetworkMessage> void registerMainThread( int id, Supplier<T> factory )
-    {
-        registerMainThread( id, getType( factory ), buf -> {
-            T instance = factory.get();
-            instance.fromBytes( buf );
-            return instance;
-        } );
-    }
-
     /**
      * /** Register packet, and a thread-unsafe handler for it.
      *

src/main/java/dan200/computercraft/shared/network/NetworkMessage.java

@@ -25,18 +25,6 @@ public interface NetworkMessage
      */
     void toBytes( @Nonnull PacketByteBuf buf );
 
-    /**
-     * Read this packet from a buffer.
-     *
-     * This may be called on any thread, so this should be a pure operation.
-     *
-     * @param buf The buffer to read data from.
-     */
-    default void fromBytes( @Nonnull PacketByteBuf buf )
-    {
-        throw new IllegalStateException( "Should have been registered using a \"from bytes\" method" );
-    }
-
     /**
      * Handle this {@link NetworkMessage}.
      *

src/main/java/dan200/computercraft/shared/network/client/ChatTableClientMessage.java

@@ -19,7 +19,7 @@ import javax.annotation.Nonnull;
 
 public class ChatTableClientMessage implements NetworkMessage
 {
-    private TableBuilder table;
+    private final TableBuilder table;
 
     public ChatTableClientMessage( TableBuilder table )
     {
@@ -30,39 +30,7 @@ public class ChatTableClientMessage implements NetworkMessage
         this.table = table;
     }
 
-    public ChatTableClientMessage()
+    public ChatTableClientMessage(@Nonnull PacketByteBuf buf)
-    {
-    }
-
-    @Override
-    public void toBytes( @Nonnull PacketByteBuf buf )
-    {
-        buf.writeVarInt( table.getId() );
-        buf.writeVarInt( table.getColumns() );
-        buf.writeBoolean( table.getHeaders() != null );
-        if( table.getHeaders() != null )
-        {
-            for( Text header : table.getHeaders() )
-            {
-                buf.writeText( header );
-            }
-        }
-
-        buf.writeVarInt( table.getRows()
-            .size() );
-        for( Text[] row : table.getRows() )
-        {
-            for( Text column : row )
-            {
-                buf.writeText( column );
-            }
-        }
-
-        buf.writeVarInt( table.getAdditional() );
-    }
-
-    @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
     {
         int id = buf.readVarInt();
         int columns = buf.readVarInt();
@@ -96,6 +64,33 @@ public class ChatTableClientMessage implements NetworkMessage
         this.table = table;
     }
 
+    @Override
+    public void toBytes( @Nonnull PacketByteBuf buf )
+    {
+        buf.writeVarInt( table.getId() );
+        buf.writeVarInt( table.getColumns() );
+        buf.writeBoolean( table.getHeaders() != null );
+        if( table.getHeaders() != null )
+        {
+            for( Text header : table.getHeaders() )
+            {
+                buf.writeText( header );
+            }
+        }
+
+        buf.writeVarInt( table.getRows()
+            .size() );
+        for( Text[] row : table.getRows() )
+        {
+            for( Text column : row )
+            {
+                buf.writeText( column );
+            }
+        }
+
+        buf.writeVarInt( table.getAdditional() );
+    }
+
     @Override
     @Environment( EnvType.CLIENT )
     public void handle( PacketContext context )

src/main/java/dan200/computercraft/shared/network/client/ComputerClientMessage.java

@@ -18,15 +18,16 @@ import javax.annotation.Nonnull;
  */
 public abstract class ComputerClientMessage implements NetworkMessage
 {
-    private int instanceId;
+    private final int instanceId;
 
     public ComputerClientMessage( int instanceId )
     {
         this.instanceId = instanceId;
     }
 
-    public ComputerClientMessage()
+    public ComputerClientMessage( @Nonnull PacketByteBuf buf )
     {
+        instanceId = buf.readVarInt();
     }
 
     public int getInstanceId()
@@ -40,12 +41,6 @@ public abstract class ComputerClientMessage implements NetworkMessage
         buf.writeVarInt( instanceId );
     }
 
-    @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
-    {
-        instanceId = buf.readVarInt();
-    }
-
     public ClientComputer getComputer()
     {
         ClientComputer computer = ComputerCraft.clientComputerRegistry.get( instanceId );

src/main/java/dan200/computercraft/shared/network/client/ComputerDataClientMessage.java

@@ -19,8 +19,8 @@ import javax.annotation.Nonnull;
  */
 public class ComputerDataClientMessage extends ComputerClientMessage
 {
-    private ComputerState state;
+    private final ComputerState state;
-    private NbtCompound userData;
+    private final NbtCompound userData;
 
     public ComputerDataClientMessage( ServerComputer computer )
     {
@@ -29,8 +29,11 @@ public class ComputerDataClientMessage extends ComputerClientMessage
         userData = computer.getUserData();
     }
 
-    public ComputerDataClientMessage()
+    public ComputerDataClientMessage( @Nonnull PacketByteBuf buf )
     {
+        super( buf );
+        state = buf.readEnumConstant( ComputerState.class );
+        userData = buf.readNbt();
     }
 
     @Override
@@ -41,14 +44,6 @@ public class ComputerDataClientMessage extends ComputerClientMessage
         buf.writeNbt( userData );
     }
 
-    @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
-    {
-        super.fromBytes( buf );
-        state = buf.readEnumConstant( ComputerState.class );
-        userData = buf.readNbt();
-    }
-
     @Override
     public void handle( PacketContext context )
     {

src/main/java/dan200/computercraft/shared/network/client/ComputerDeletedClientMessage.java

@@ -8,6 +8,7 @@ package dan200.computercraft.shared.network.client;
 
 import dan200.computercraft.ComputerCraft;
 import net.fabricmc.fabric.api.network.PacketContext;
+import net.minecraft.network.PacketByteBuf;
 
 public class ComputerDeletedClientMessage extends ComputerClientMessage
 {
@@ -16,8 +17,9 @@ public class ComputerDeletedClientMessage extends ComputerClientMessage
         super( instanceId );
     }
 
-    public ComputerDeletedClientMessage()
+    public ComputerDeletedClientMessage( PacketByteBuf buffer )
     {
+        super( buffer );
     }
 
     @Override

src/main/java/dan200/computercraft/shared/network/client/ComputerTerminalClientMessage.java

@@ -13,7 +13,7 @@ import javax.annotation.Nonnull;
 
 public class ComputerTerminalClientMessage extends ComputerClientMessage
 {
-    private TerminalState state;
+    private final TerminalState state;
 
     public ComputerTerminalClientMessage( int instanceId, TerminalState state )
     {
@@ -21,8 +21,10 @@ public class ComputerTerminalClientMessage extends ComputerClientMessage
         this.state = state;
     }
 
-    public ComputerTerminalClientMessage()
+    public ComputerTerminalClientMessage( @Nonnull PacketByteBuf buf )
     {
+        super( buf );
+        state = new TerminalState( buf );
     }
 
     @Override
@@ -32,13 +34,6 @@ public class ComputerTerminalClientMessage extends ComputerClientMessage
         state.write( buf );
     }
 
-    @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
-    {
-        super.fromBytes( buf );
-        state = new TerminalState( buf );
-    }
-
     @Override
     public void handle( PacketContext context )
     {

src/main/java/dan200/computercraft/shared/network/client/UploadResultMessage.java

@@ -0,0 +1,58 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.network.client;
+
+import dan200.computercraft.client.gui.ComputerScreenBase;
+import dan200.computercraft.client.gui.OptionScreen;
+import dan200.computercraft.shared.computer.upload.UploadResult;
+import dan200.computercraft.shared.network.NetworkMessage;
+import net.fabricmc.fabric.api.network.PacketContext;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.network.PacketByteBuf;
+import net.minecraft.text.Text;
+
+import javax.annotation.Nonnull;
+
+public class UploadResultMessage implements NetworkMessage
+{
+    public static final UploadResultMessage COMPUTER_OFF = new UploadResultMessage( UploadResult.ERROR, UploadResult.COMPUTER_OFF_MSG );
+    public static final UploadResultMessage OUT_OF_SPACE = new UploadResultMessage( UploadResult.ERROR, UploadResult.OUT_OF_SPACE_MSG );
+
+    private final UploadResult result;
+    private final Text message;
+
+    public UploadResultMessage( UploadResult result, Text message )
+    {
+        this.result = result;
+        this.message = message;
+    }
+
+    public UploadResultMessage( @Nonnull PacketByteBuf buf )
+    {
+        result = buf.readEnumConstant( UploadResult.class );
+        message = buf.readText();
+    }
+
+    @Override
+    public void toBytes( @Nonnull PacketByteBuf buf )
+    {
+        buf.writeEnumConstant( result );
+        buf.writeText( message );
+    }
+
+    @Override
+    public void handle( PacketContext context )
+    {
+        MinecraftClient minecraft = MinecraftClient.getInstance();
+
+        Screen screen = OptionScreen.unwrap( minecraft.currentScreen );
+        if( screen instanceof ComputerScreenBase<?> )
+        {
+            ((ComputerScreenBase<?>) screen).uploadResult( result, message );
+        }
+    }
+}

src/main/java/dan200/computercraft/shared/network/container/ComputerContainerData.java

@@ -6,17 +6,14 @@
 
 package dan200.computercraft.shared.network.container;
 
-import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ServerComputer;
 import net.minecraft.network.PacketByteBuf;
-import net.minecraft.util.Identifier;
 
 public class ComputerContainerData implements ContainerData
 {
-    private static final Identifier IDENTIFIER = new Identifier( ComputerCraft.MOD_ID, "computer_container_data" );
+    private final int id;
-    private int id;
+    private final ComputerFamily family;
-    private ComputerFamily family;
 
     public ComputerContainerData( ServerComputer computer )
     {
@@ -26,18 +23,8 @@ public class ComputerContainerData implements ContainerData
 
     public ComputerContainerData( PacketByteBuf byteBuf )
     {
-        fromBytes( byteBuf );
+        id = byteBuf.readInt();
-    }
+        family = byteBuf.readEnumConstant( ComputerFamily.class );
-
-    public void fromBytes( PacketByteBuf buf )
-    {
-        id = buf.readInt();
-        family = buf.readEnumConstant( ComputerFamily.class );
-    }
-
-    public Identifier getId()
-    {
-        return IDENTIFIER;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/network/container/ContainerData.java

@@ -6,6 +6,7 @@
 
 package dan200.computercraft.shared.network.container;
 
+import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import net.fabricmc.fabric.api.screenhandler.v1.ScreenHandlerRegistry;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.PlayerInventory;
@@ -23,19 +24,28 @@ import java.util.function.Function;
  */
 public interface ContainerData
 {
-    static <C extends ScreenHandler, T extends ContainerData> ScreenHandlerType<C> toType( Identifier identifier, Function<PacketByteBuf, T> reader,
+    static <C extends ScreenHandler, T extends ContainerData> ScreenHandlerType<C> toType(Identifier identifier, Function<PacketByteBuf, T> reader,
-                                                                                           Factory<C, T> factory )
+                                                                                          Factory<C, T> factory )
     {
         return ScreenHandlerRegistry.registerExtended( identifier,
             ( id, playerInventory, packetByteBuf ) -> factory.create( id,
                 playerInventory,
                 reader.apply( packetByteBuf ) ) );
     }
+    static <C extends ScreenHandler, T extends ContainerData> ScreenHandlerType<C> toType(Identifier identifier, ScreenHandlerType<C> type, Function<PacketByteBuf, T> reader,
+                                                                                          FixedFactory<C, T> factory )
+    {
+        return ScreenHandlerRegistry.registerExtended( identifier,
+            ( id, playerInventory, packetByteBuf ) -> factory.create( type, id,
+                playerInventory,
+                reader.apply( packetByteBuf ) ) );
+    }
 
     void toBytes( PacketByteBuf buf );
 
     default void open( PlayerEntity player, NamedScreenHandlerFactory owner )
     {
+        if (player.world.isClient) return;
         player.openHandledScreen( owner );
     }
 
@@ -43,4 +53,9 @@ public interface ContainerData
     {
         C create( int id, @Nonnull PlayerInventory inventory, T data );
     }
+
+    interface FixedFactory<C extends ScreenHandler, T extends ContainerData>
+    {
+        C create( ScreenHandlerType<C> type, int id, @Nonnull PlayerInventory inventory, T data );
+    }
 }

src/main/java/dan200/computercraft/shared/network/container/ViewComputerContainerData.java

@@ -21,9 +21,8 @@ import javax.annotation.Nonnull;
  */
 public class ViewComputerContainerData extends ComputerContainerData
 {
-    private static final Identifier IDENTIFIER = new Identifier( ComputerCraft.MOD_ID, "view_computer_container_data" );
+    private final int width;
-    private int width;
+    private final int height;
-    private int height;
 
     public ViewComputerContainerData( ServerComputer computer )
     {
@@ -40,24 +39,11 @@ public class ViewComputerContainerData extends ComputerContainerData
         }
     }
 
-    public ViewComputerContainerData( PacketByteBuf packetByteBuf )
+    public ViewComputerContainerData( PacketByteBuf buffer )
     {
-        super( new PacketByteBuf( packetByteBuf.copy() ) );
+        super( buffer );
-        fromBytes( packetByteBuf );
+        width = buffer.readVarInt();
-    }
+        height = buffer.readVarInt();
-
-    @Override
-    public void fromBytes( PacketByteBuf buf )
-    {
-        super.fromBytes( buf );
-        width = buf.readVarInt();
-        height = buf.readVarInt();
-    }
-
-    @Override
-    public Identifier getId()
-    {
-        return IDENTIFIER;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/network/server/ComputerActionServerMessage.java

@@ -8,13 +8,14 @@ package dan200.computercraft.shared.network.server;
 
 import dan200.computercraft.shared.computer.core.IContainerComputer;
 import dan200.computercraft.shared.computer.core.ServerComputer;
+import net.fabricmc.fabric.api.network.PacketContext;
 import net.minecraft.network.PacketByteBuf;
 
 import javax.annotation.Nonnull;
 
 public class ComputerActionServerMessage extends ComputerServerMessage
 {
-    private Action action;
+    private final Action action;
 
     public ComputerActionServerMessage( int instanceId, Action action )
     {
@@ -22,8 +23,10 @@ public class ComputerActionServerMessage extends ComputerServerMessage
         this.action = action;
     }
 
-    public ComputerActionServerMessage()
+    public ComputerActionServerMessage( @Nonnull PacketByteBuf buf )
     {
+        super( buf );
+        action = buf.readEnumConstant( Action.class );
     }
 
     @Override
@@ -34,14 +37,7 @@ public class ComputerActionServerMessage extends ComputerServerMessage
     }
 
     @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
+    protected void handle(PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
-    {
-        super.fromBytes( buf );
-        action = buf.readEnumConstant( Action.class );
-    }
-
-    @Override
-    protected void handle( @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
     {
         switch( action )
         {

src/main/java/dan200/computercraft/shared/network/server/ComputerServerMessage.java

@@ -22,15 +22,16 @@ import javax.annotation.Nonnull;
  */
 public abstract class ComputerServerMessage implements NetworkMessage
 {
-    private int instanceId;
+    private final int instanceId;
 
     public ComputerServerMessage( int instanceId )
     {
         this.instanceId = instanceId;
     }
 
-    public ComputerServerMessage()
+    public ComputerServerMessage( @Nonnull PacketByteBuf buf )
     {
+        instanceId = buf.readVarInt();
     }
 
     @Override
@@ -39,12 +40,6 @@ public abstract class ComputerServerMessage implements NetworkMessage
         buf.writeVarInt( instanceId );
     }
 
-    @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
-    {
-        instanceId = buf.readVarInt();
-    }
-
     @Override
     public void handle( PacketContext context )
     {
@@ -60,8 +55,8 @@ public abstract class ComputerServerMessage implements NetworkMessage
             return;
         }
 
-        handle( computer, container );
+        handle( context, computer, container );
     }
 
-    protected abstract void handle( @Nonnull ServerComputer computer, @Nonnull IContainerComputer container );
+    protected abstract void handle( PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container );
 }

src/main/java/dan200/computercraft/shared/network/server/ContinueUploadMessage.java

@@ -0,0 +1,46 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.network.server;
+
+import dan200.computercraft.shared.computer.core.IContainerComputer;
+import dan200.computercraft.shared.computer.core.ServerComputer;
+import net.fabricmc.fabric.api.network.PacketContext;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.network.PacketByteBuf;
+import net.minecraft.server.network.ServerPlayerEntity;
+
+import javax.annotation.Nonnull;
+
+public class ContinueUploadMessage extends ComputerServerMessage
+{
+    private final boolean overwrite;
+
+    public ContinueUploadMessage( int instanceId, boolean overwrite )
+    {
+        super( instanceId );
+        this.overwrite = overwrite;
+    }
+
+    public ContinueUploadMessage( @Nonnull PacketByteBuf buf )
+    {
+        super( buf );
+        overwrite = buf.readBoolean();
+    }
+
+    @Override
+    public void toBytes( @Nonnull PacketByteBuf buf )
+    {
+        super.toBytes( buf );
+        buf.writeBoolean( overwrite );
+    }
+
+    @Override
+    protected void handle(PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
+    {
+        ServerPlayerEntity player = (ServerPlayerEntity) context.getPlayer();
+        if( player != null ) container.confirmUpload( player, overwrite );
+    }
+}

src/main/java/dan200/computercraft/shared/network/server/KeyEventServerMessage.java

@@ -9,6 +9,7 @@ package dan200.computercraft.shared.network.server;
 import dan200.computercraft.shared.computer.core.IContainerComputer;
 import dan200.computercraft.shared.computer.core.InputState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
+import net.fabricmc.fabric.api.network.PacketContext;
 import net.minecraft.network.PacketByteBuf;
 
 import javax.annotation.Nonnull;
@@ -19,8 +20,8 @@ public class KeyEventServerMessage extends ComputerServerMessage
     public static final int TYPE_REPEAT = 1;
     public static final int TYPE_UP = 2;
 
-    private int type;
+    private final int type;
-    private int key;
+    private final int key;
 
     public KeyEventServerMessage( int instanceId, int type, int key )
     {
@@ -29,8 +30,11 @@ public class KeyEventServerMessage extends ComputerServerMessage
         this.key = key;
     }
 
-    public KeyEventServerMessage()
+    public KeyEventServerMessage( @Nonnull PacketByteBuf buf )
     {
+        super( buf );
+        type = buf.readByte();
+        key = buf.readVarInt();
     }
 
     @Override
@@ -42,15 +46,7 @@ public class KeyEventServerMessage extends ComputerServerMessage
     }
 
     @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
+    protected void handle(PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
-    {
-        super.fromBytes( buf );
-        type = buf.readByte();
-        key = buf.readVarInt();
-    }
-
-    @Override
-    protected void handle( @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
     {
         InputState input = container.getInput();
         if( type == TYPE_UP )

src/main/java/dan200/computercraft/shared/network/server/MouseEventServerMessage.java

@@ -9,6 +9,7 @@ package dan200.computercraft.shared.network.server;
 import dan200.computercraft.shared.computer.core.IContainerComputer;
 import dan200.computercraft.shared.computer.core.InputState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
+import net.fabricmc.fabric.api.network.PacketContext;
 import net.minecraft.network.PacketByteBuf;
 
 import javax.annotation.Nonnull;
@@ -20,10 +21,10 @@ public class MouseEventServerMessage extends ComputerServerMessage
     public static final int TYPE_UP = 2;
     public static final int TYPE_SCROLL = 3;
 
-    private int type;
+    private final int type;
-    private int x;
+    private final int x;
-    private int y;
+    private final int y;
-    private int arg;
+    private final int arg;
 
     public MouseEventServerMessage( int instanceId, int type, int arg, int x, int y )
     {
@@ -34,8 +35,13 @@ public class MouseEventServerMessage extends ComputerServerMessage
         this.y = y;
     }
 
-    public MouseEventServerMessage()
+    public MouseEventServerMessage( @Nonnull PacketByteBuf buf )
     {
+        super( buf );
+        type = buf.readByte();
+        arg = buf.readVarInt();
+        x = buf.readVarInt();
+        y = buf.readVarInt();
     }
 
     @Override
@@ -49,17 +55,7 @@ public class MouseEventServerMessage extends ComputerServerMessage
     }
 
     @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
+    protected void handle(PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
-    {
-        super.fromBytes( buf );
-        type = buf.readByte();
-        arg = buf.readVarInt();
-        x = buf.readVarInt();
-        y = buf.readVarInt();
-    }
-
-    @Override
-    protected void handle( @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
     {
         InputState input = container.getInput();
         switch( type )

src/main/java/dan200/computercraft/shared/network/server/QueueEventServerMessage.java

@@ -9,6 +9,7 @@ package dan200.computercraft.shared.network.server;
 import dan200.computercraft.shared.computer.core.IContainerComputer;
 import dan200.computercraft.shared.computer.core.ServerComputer;
 import dan200.computercraft.shared.util.NBTUtil;
+import net.fabricmc.fabric.api.network.PacketContext;
 import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 
@@ -23,8 +24,8 @@ import javax.annotation.Nullable;
  */
 public class QueueEventServerMessage extends ComputerServerMessage
 {
-    private String event;
+    private final String event;
-    private Object[] args;
+    private final Object[] args;
 
     public QueueEventServerMessage( int instanceId, @Nonnull String event, @Nullable Object[] args )
     {
@@ -33,8 +34,13 @@ public class QueueEventServerMessage extends ComputerServerMessage
         this.args = args;
     }
 
-    public QueueEventServerMessage()
+    public QueueEventServerMessage( @Nonnull PacketByteBuf buf )
     {
+        super( buf );
+        event = buf.readString( Short.MAX_VALUE );
+
+        NbtCompound args = buf.readNbt();
+        this.args = args == null ? null : NBTUtil.decodeObjects( args );
     }
 
     @Override
@@ -46,17 +52,7 @@ public class QueueEventServerMessage extends ComputerServerMessage
     }
 
     @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
+    protected void handle(PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
-    {
-        super.fromBytes( buf );
-        event = buf.readString( Short.MAX_VALUE );
-
-        NbtCompound args = buf.readNbt();
-        this.args = args == null ? null : NBTUtil.decodeObjects( args );
-    }
-
-    @Override
-    protected void handle( @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
     {
         computer.queueEvent( event, args );
     }

src/main/java/dan200/computercraft/shared/network/server/RequestComputerMessage.java

@@ -16,15 +16,16 @@ import javax.annotation.Nonnull;
 
 public class RequestComputerMessage implements NetworkMessage
 {
-    private int instance;
+    private final int instance;
 
     public RequestComputerMessage( int instance )
     {
         this.instance = instance;
     }
 
-    public RequestComputerMessage()
+    public RequestComputerMessage( @Nonnull PacketByteBuf buf )
     {
+        instance = buf.readVarInt();
     }
 
     @Override
@@ -33,12 +34,6 @@ public class RequestComputerMessage implements NetworkMessage
         buf.writeVarInt( instance );
     }
 
-    @Override
-    public void fromBytes( @Nonnull PacketByteBuf buf )
-    {
-        instance = buf.readVarInt();
-    }
-
     @Override
     public void handle( PacketContext context )
     {

src/main/java/dan200/computercraft/shared/network/server/UploadFileMessage.java

@@ -0,0 +1,187 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.network.server;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.computer.core.IContainerComputer;
+import dan200.computercraft.shared.computer.core.ServerComputer;
+import dan200.computercraft.shared.computer.upload.FileSlice;
+import dan200.computercraft.shared.computer.upload.FileUpload;
+import dan200.computercraft.shared.network.NetworkHandler;
+import io.netty.handler.codec.DecoderException;
+import net.fabricmc.fabric.api.network.PacketContext;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.network.PacketByteBuf;
+import net.minecraft.server.network.ServerPlayerEntity;
+
+import javax.annotation.Nonnull;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+
+public class UploadFileMessage extends ComputerServerMessage
+{
+    public static final int MAX_SIZE = 512 * 1024;
+    static final int MAX_PACKET_SIZE = 30 * 1024; // Max packet size is 32767.
+
+    public static final int MAX_FILES = 32;
+    public static final int MAX_FILE_NAME = 128;
+
+    private static final int FLAG_FIRST = 1;
+    private static final int FLAG_LAST = 2;
+
+    private final UUID uuid;
+    private final int flag;
+    private final List<FileUpload> files;
+    private final List<FileSlice> slices;
+
+    UploadFileMessage( int instanceId, UUID uuid, int flag, List<FileUpload> files, List<FileSlice> slices )
+    {
+        super( instanceId );
+        this.uuid = uuid;
+        this.flag = flag;
+        this.files = files;
+        this.slices = slices;
+    }
+
+    public UploadFileMessage( @Nonnull PacketByteBuf buf )
+    {
+        super( buf );
+        uuid = buf.readUuid();
+        int flag = this.flag = buf.readByte();
+
+        int totalSize = 0;
+        if( (flag & FLAG_FIRST) != 0 )
+        {
+            int nFiles = buf.readVarInt();
+            if( nFiles >= MAX_FILES ) throw new DecoderException( "Too many files" );
+
+            List<FileUpload> files = this.files = new ArrayList<>( nFiles );
+            for( int i = 0; i < nFiles; i++ )
+            {
+                String name = buf.readString( MAX_FILE_NAME );
+                int size = buf.readVarInt();
+                if( size > MAX_SIZE || (totalSize += size) >= MAX_SIZE )
+                {
+                    throw new DecoderException( "Files are too large" );
+                }
+
+                byte[] digest = new byte[FileUpload.CHECKSUM_LENGTH];
+                buf.readBytes( digest );
+
+                files.add( new FileUpload( name, ByteBuffer.allocateDirect( size ), digest ) );
+            }
+        }
+        else
+        {
+            files = null;
+        }
+
+        int nSlices = buf.readVarInt();
+        List<FileSlice> slices = this.slices = new ArrayList<>( nSlices );
+        for( int i = 0; i < nSlices; i++ )
+        {
+            int fileId = buf.readUnsignedByte();
+            int offset = buf.readVarInt();
+
+            int size = buf.readUnsignedShort();
+            if( size > MAX_PACKET_SIZE ) throw new DecoderException( "File is too large" );
+
+            ByteBuffer buffer = ByteBuffer.allocateDirect( size );
+            buf.readBytes( buffer );
+            buffer.flip();
+
+            slices.add( new FileSlice( fileId, offset, buffer ) );
+        }
+    }
+
+    @Override
+    public void toBytes( @Nonnull PacketByteBuf buf )
+    {
+        super.toBytes( buf );
+        buf.writeUuid( uuid );
+        buf.writeByte( flag );
+
+        if( (flag & FLAG_FIRST) != 0 )
+        {
+            buf.writeVarInt( files.size() );
+            for( FileUpload file : files )
+            {
+                buf.writeString( file.getName(), MAX_FILE_NAME );
+                buf.writeVarInt( file.getLength() );
+                buf.writeBytes( file.getChecksum() );
+            }
+        }
+
+        buf.writeVarInt( slices.size() );
+        for( FileSlice slice : slices )
+        {
+            buf.writeByte( slice.getFileId() );
+            buf.writeVarInt( slice.getOffset() );
+
+            slice.getBytes().rewind();
+            buf.writeShort( slice.getBytes().remaining() );
+            buf.writeBytes( slice.getBytes() );
+        }
+    }
+
+    public static void send( int instanceId, List<FileUpload> files )
+    {
+        UUID uuid = UUID.randomUUID();
+
+        int remaining = MAX_PACKET_SIZE;
+        for( FileUpload file : files ) remaining -= file.getName().length() * 4 + FileUpload.CHECKSUM_LENGTH;
+
+        boolean first = true;
+        List<FileSlice> slices = new ArrayList<>( files.size() );
+        for( int fileId = 0; fileId < files.size(); fileId++ )
+        {
+            FileUpload file = files.get( fileId );
+            ByteBuffer contents = file.getBytes();
+            int capacity = contents.limit();
+
+            int currentOffset = 0;
+            while( currentOffset < capacity )
+            {
+                if( remaining <= 0 )
+                {
+                    NetworkHandler.sendToServer( first
+                        ? new UploadFileMessage( instanceId, uuid, FLAG_FIRST, files, new ArrayList<>( slices ) )
+                        : new UploadFileMessage( instanceId, uuid, 0, null, new ArrayList<>( slices ) ) );
+                    slices.clear();
+                    remaining = MAX_PACKET_SIZE;
+                    first = false;
+                }
+
+                int canWrite = Math.min( remaining, capacity - currentOffset );
+
+                ComputerCraft.log.info( "Adding slice from {} to {}", currentOffset, currentOffset + canWrite - 1 );
+                contents.position( currentOffset ).limit( currentOffset + canWrite );
+                slices.add( new FileSlice( fileId, currentOffset, contents.slice() ) );
+                currentOffset += canWrite;
+            }
+
+            contents.position( 0 ).limit( capacity );
+        }
+
+        NetworkHandler.sendToServer( first
+            ? new UploadFileMessage( instanceId, uuid, FLAG_FIRST | FLAG_LAST, files, new ArrayList<>( slices ) )
+            : new UploadFileMessage( instanceId, uuid, FLAG_LAST, null, new ArrayList<>( slices ) ) );
+    }
+
+    @Override
+    protected void handle(PacketContext context, @Nonnull ServerComputer computer, @Nonnull IContainerComputer container )
+    {
+        ServerPlayerEntity player = (ServerPlayerEntity) context.getPlayer();
+        if( player != null )
+        {
+            if( (flag & FLAG_FIRST) != 0 ) container.startUpload( uuid, files );
+            container.continueUpload( uuid, slices );
+            if( (flag & FLAG_LAST) != 0 ) container.finishUpload( player, uuid );
+        }
+    }
+}

src/main/java/dan200/computercraft/shared/peripheral/monitor/TileMonitor.java

@@ -170,8 +170,6 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
 
         int oldXIndex = xIndex;
         int oldYIndex = yIndex;
-        int oldWidth = width;
-        int oldHeight = height;
 
         xIndex = nbt.getInt( NBT_X );
         yIndex = nbt.getInt( NBT_Y );
@@ -182,27 +180,14 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
         {
             // If our index has changed then it's possible the origin monitor has changed. Thus
             // we'll clear our cache. If we're the origin then we'll need to remove the glList as well.
-            if( oldXIndex == 0 && oldYIndex == 0 && clientMonitor != null )
+            if( oldXIndex == 0 && oldYIndex == 0 && clientMonitor != null ) clientMonitor.destroy();
-            {
-                clientMonitor.destroy();
-            }
             clientMonitor = null;
         }
 
         if( xIndex == 0 && yIndex == 0 )
         {
             // If we're the origin terminal then create it.
-            if( clientMonitor == null )
+            if( clientMonitor == null ) clientMonitor = new ClientMonitor( advanced, this );
-            {
-                clientMonitor = new ClientMonitor( advanced, this );
-            }
-            clientMonitor.readDescription( nbt );
-        }
-
-        if( oldXIndex != xIndex || oldYIndex != yIndex || oldWidth != width || oldHeight != height )
-        {
-            // One of our properties has changed, so ensure we redraw the block
-            updateBlock();
         }
     }
 
@@ -214,11 +199,6 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
         nbt.putInt( NBT_Y, yIndex );
         nbt.putInt( NBT_WIDTH, width );
         nbt.putInt( NBT_HEIGHT, height );
-
-        if( xIndex == 0 && yIndex == 0 && serverMonitor != null )
-        {
-            serverMonitor.writeDescription( nbt );
-        }
     }
 
     private TileMonitor getNeighbour( int x, int y )

src/main/java/dan200/computercraft/shared/peripheral/speaker/TileSpeaker.java

@@ -31,7 +31,7 @@ public class TileSpeaker extends TileGeneric implements IPeripheralTile
         super( type, pos, state );
         peripheral = new Peripheral( this );
     }
-    
+
     public static void tick( World world, BlockPos pos, BlockState state, TileSpeaker tileSpeaker )
     {
         tileSpeaker.peripheral.update();

src/main/java/dan200/computercraft/shared/pocket/inventory/ContainerPocketComputer.java

@@ -1,78 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.shared.pocket.inventory;
-
-import dan200.computercraft.shared.ComputerCraftRegistry;
-import dan200.computercraft.shared.computer.core.ServerComputer;
-import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
-import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
-import net.fabricmc.fabric.api.screenhandler.v1.ExtendedScreenHandlerFactory;
-import net.minecraft.entity.player.PlayerEntity;
-import net.minecraft.entity.player.PlayerInventory;
-import net.minecraft.item.ItemStack;
-import net.minecraft.network.PacketByteBuf;
-import net.minecraft.screen.ScreenHandler;
-import net.minecraft.server.network.ServerPlayerEntity;
-import net.minecraft.text.Text;
-import net.minecraft.util.Hand;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
-public final class ContainerPocketComputer extends ContainerComputerBase
-{
-    private ContainerPocketComputer( int id, ServerComputer computer, ItemPocketComputer item, Hand hand )
-    {
-        super( ComputerCraftRegistry.ModContainers.POCKET_COMPUTER, id, p -> {
-            ItemStack stack = p.getStackInHand( hand );
-            return stack.getItem() == item && ItemPocketComputer.getServerComputer( stack ) == computer;
-        }, computer, item.getFamily() );
-    }
-
-    public ContainerPocketComputer( int id, PlayerInventory player, PacketByteBuf packetByteBuf )
-    {
-        super( ComputerCraftRegistry.ModContainers.POCKET_COMPUTER, id, player, packetByteBuf );
-    }
-
-    public static class Factory implements ExtendedScreenHandlerFactory
-    {
-        private final ServerComputer computer;
-        private final Text name;
-        private final ItemPocketComputer item;
-        private final Hand hand;
-
-        public Factory( ServerComputer computer, ItemStack stack, ItemPocketComputer item, Hand hand )
-        {
-            this.computer = computer;
-            name = stack.getName();
-            this.item = item;
-            this.hand = hand;
-        }
-
-
-        @Nonnull
-        @Override
-        public Text getDisplayName()
-        {
-            return name;
-        }
-
-        @Nullable
-        @Override
-        public ScreenHandler createMenu( int id, @Nonnull PlayerInventory inventory, @Nonnull PlayerEntity entity )
-        {
-            return new ContainerPocketComputer( id, computer, item, hand );
-        }
-
-        @Override
-        public void writeScreenOpeningData( ServerPlayerEntity serverPlayerEntity, PacketByteBuf packetByteBuf )
-        {
-            packetByteBuf.writeInt( computer.getInstanceID() );
-            packetByteBuf.writeEnumConstant( computer.getFamily() );
-        }
-    }
-}

src/main/java/dan200/computercraft/shared/pocket/inventory/PocketComputerMenuProvider.java

@@ -0,0 +1,71 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.pocket.inventory;
+
+import dan200.computercraft.shared.ComputerCraftRegistry;
+import dan200.computercraft.shared.computer.core.ComputerFamily;
+import dan200.computercraft.shared.computer.core.ServerComputer;
+import dan200.computercraft.shared.computer.inventory.ComputerMenuWithoutInventory;
+import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
+import net.fabricmc.fabric.api.screenhandler.v1.ExtendedScreenHandlerFactory;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.entity.player.PlayerInventory;
+import net.minecraft.item.ItemStack;
+import net.minecraft.network.PacketByteBuf;
+import net.minecraft.screen.NamedScreenHandlerFactory;
+import net.minecraft.screen.ScreenHandler;
+import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.text.Text;
+import net.minecraft.util.Hand;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+public class PocketComputerMenuProvider implements NamedScreenHandlerFactory, ExtendedScreenHandlerFactory
+{
+    private final ServerComputer computer;
+    private final Text name;
+    private final ItemPocketComputer item;
+    private final Hand hand;
+    private final boolean isTypingOnly;
+
+    public PocketComputerMenuProvider(ServerComputer computer, ItemStack stack, ItemPocketComputer item, Hand hand, boolean isTypingOnly )
+    {
+        this.computer = computer;
+        name = stack.getName();
+        this.item = item;
+        this.hand = hand;
+        this.isTypingOnly = isTypingOnly;
+    }
+
+
+    @Nonnull
+    @Override
+    public Text getDisplayName()
+    {
+        return name;
+    }
+
+    @Nullable
+    @Override
+    public ScreenHandler createMenu(int id, @Nonnull PlayerInventory inventory, @Nonnull PlayerEntity entity )
+    {
+        return new ComputerMenuWithoutInventory(
+            isTypingOnly ? ComputerCraftRegistry.ModContainers.POCKET_COMPUTER_NO_TERM : ComputerCraftRegistry.ModContainers.POCKET_COMPUTER, id, inventory,
+            p -> {
+                ItemStack stack = p.getStackInHand( hand );
+                return stack.getItem() == item && ItemPocketComputer.getServerComputer( stack ) == computer;
+            },
+            computer, item.getFamily()
+        );
+    }
+
+    @Override
+    public void writeScreenOpeningData(ServerPlayerEntity player, PacketByteBuf packetByteBuf) {
+        packetByteBuf.writeInt(computer.getInstanceID());
+        packetByteBuf.writeEnumConstant(computer.getFamily());
+    }
+}

src/main/java/dan200/computercraft/shared/pocket/items/ItemPocketComputer.java

@@ -23,7 +23,7 @@ import dan200.computercraft.shared.computer.items.IComputerItem;
 import dan200.computercraft.shared.network.container.ComputerContainerData;
 import dan200.computercraft.shared.pocket.apis.PocketAPI;
 import dan200.computercraft.shared.pocket.core.PocketServerComputer;
-import dan200.computercraft.shared.pocket.inventory.ContainerPocketComputer;
+import dan200.computercraft.shared.pocket.inventory.PocketComputerMenuProvider;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
 import net.minecraft.client.item.TooltipContext;
@@ -164,8 +164,9 @@ public class ItemPocketComputer extends Item implements IComputerItem, IMedia, I
 
             if( !stop && computer != null )
             {
-                computer.sendTerminalState( player );
+//                computer.sendTerminalState( player );
-                new ComputerContainerData( computer ).open( player, new ContainerPocketComputer.Factory( computer, stack, this, hand ) );
+                boolean isTypingOnly = hand == Hand.OFF_HAND;
+                new ComputerContainerData( computer ).open( player, new PocketComputerMenuProvider( computer, stack, this, hand, isTypingOnly ) );
             }
         }
         return new TypedActionResult<>( ActionResult.SUCCESS, stack );

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

@@ -0,0 +1,39 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2021. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.util;
+
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.inventory.Inventory;
+import net.minecraft.item.ItemStack;
+import net.minecraft.screen.slot.Slot;
+
+import javax.annotation.Nonnull;
+
+public class InvisibleSlot extends Slot
+{
+    public InvisibleSlot(Inventory container, int slot )
+    {
+        super( container, slot, 0, 0 );
+    }
+
+    @Override
+    public boolean canInsert( @Nonnull ItemStack stack )
+    {
+        return false;
+    }
+
+    @Override
+    public boolean canTakeItems( @Nonnull PlayerEntity player )
+    {
+        return false;
+    }
+
+    @Override
+    public boolean isEnabled()
+    {
+        return false;
+    }
+}

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

@@ -0,0 +1,15 @@
+package dan200.computercraft.shared.util;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Equivalent to {@link Supplier}, except with nonnull contract.
+ *
+ * @see Supplier
+ */
+@FunctionalInterface
+public interface NonNullSupplier<T>
+{
+    @Nonnull
+    T get();
+}