Add invisible slots to computer GUIs

This ensures inventory slots are synced while the container is open,
meaning the hotbar (which is visible underneath the GUI) correctly
updates.

Fixes #915

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

@@ -18,6 +18,7 @@ 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.ComputerMenuWithoutInventory;
 import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
 import dan200.computercraft.shared.computer.inventory.ContainerViewComputer;
 import dan200.computercraft.shared.computer.items.ItemComputer;
@@ -312,13 +313,13 @@ public final class Registry
         static final DeferredRegister<ContainerType<?>> CONTAINERS = DeferredRegister.create( ForgeRegistries.CONTAINERS, ComputerCraft.MOD_ID );
 
         public static final RegistryObject<ContainerType<ContainerComputerBase>> COMPUTER = CONTAINERS.register( "computer",
-            () -> ContainerData.toType( ComputerContainerData::new, ContainerComputerBase::new ) );
+            () -> ContainerData.toType( ComputerContainerData::new, ComputerMenuWithoutInventory::new ) );
 
         public static final RegistryObject<ContainerType<ContainerComputerBase>> POCKET_COMPUTER = CONTAINERS.register( "pocket_computer",
-            () -> ContainerData.toType( ComputerContainerData::new, ContainerComputerBase::new ) );
+            () -> ContainerData.toType( ComputerContainerData::new, ComputerMenuWithoutInventory::new ) );
 
         public static final RegistryObject<ContainerType<ContainerComputerBase>> POCKET_COMPUTER_NO_TERM = CONTAINERS.register( "pocket_computer_no_term",
-            () -> ContainerData.toType( ComputerContainerData::new, ContainerComputerBase::new ) );
+            () -> ContainerData.toType( ComputerContainerData::new, ComputerMenuWithoutInventory::new ) );
 
         public static final RegistryObject<ContainerType<ContainerTurtle>> TURTLE = CONTAINERS.register( "turtle",
             () -> ContainerData.toType( ComputerContainerData::new, ContainerTurtle::new ) );

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

@@ -237,7 +237,7 @@ public final class CommandComputerCraft
                         @Override
                         public Container 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/computer/blocks/TileComputer.java

@@ -12,7 +12,7 @@ import dan200.computercraft.shared.Registry;
 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.ContainerComputerBase;
+import dan200.computercraft.shared.computer.inventory.ComputerMenuWithoutInventory;
 import dan200.computercraft.shared.util.CapabilityUtil;
 import net.minecraft.block.BlockState;
 import net.minecraft.entity.player.PlayerEntity;
@@ -86,7 +86,7 @@ public class TileComputer extends TileComputerBase
     @Override
     public Container createMenu( int id, @Nonnull PlayerInventory inventory, @Nonnull PlayerEntity player )
     {
-        return new ContainerComputerBase( Registry.ModContainers.COMPUTER.get(), id, this::isUsableByPlayer, createServerComputer(), getFamily() );
+        return new ComputerMenuWithoutInventory( Registry.ModContainers.COMPUTER.get(), id, inventory, this::isUsableByPlayer, createServerComputer(), getFamily() );
     }
 
     @Nonnull

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.inventory.container.ContainerType;
+
+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( ContainerType<? extends ContainerComputerBase> type, int id, PlayerInventory player, Predicate<PlayerEntity> canUse, IComputer computer, ComputerFamily family )
+    {
+        super( type, id, canUse, computer, family );
+        addSlots( player );
+    }
+
+    public ComputerMenuWithoutInventory( ContainerType<? 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/ContainerComputerBase.java

@@ -34,7 +34,7 @@ import java.util.UUID;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
-public class ContainerComputerBase extends Container implements IContainerComputer
+public abstract class ContainerComputerBase extends Container implements IContainerComputer
 {
     private static final String LIST_PREFIX = "\n \u2022 ";
 

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

@@ -16,14 +16,14 @@ import net.minecraft.entity.player.PlayerInventory;
 
 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( Registry.ModContainers.VIEW_COMPUTER.get(), id, player -> canInteractWith( computer, player ), computer, computer.getFamily() );
+        super( Registry.ModContainers.VIEW_COMPUTER.get(), id, player, p -> canInteractWith( computer, p ), computer, computer.getFamily() );
         width = height = 0;
     }
 

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

@@ -7,7 +7,7 @@ package dan200.computercraft.shared.pocket.inventory;
 
 import dan200.computercraft.shared.Registry;
 import dan200.computercraft.shared.computer.core.ServerComputer;
-import dan200.computercraft.shared.computer.inventory.ContainerComputerBase;
+import dan200.computercraft.shared.computer.inventory.ComputerMenuWithoutInventory;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.PlayerInventory;
@@ -49,8 +49,8 @@ public class PocketComputerMenuProvider implements INamedContainerProvider
     @Override
     public Container createMenu( int id, @Nonnull PlayerInventory inventory, @Nonnull PlayerEntity entity )
     {
-        return new ContainerComputerBase(
+        return new ComputerMenuWithoutInventory(
-            isTypingOnly ? Registry.ModContainers.POCKET_COMPUTER_NO_TERM.get() : Registry.ModContainers.POCKET_COMPUTER.get(), id,
+            isTypingOnly ? Registry.ModContainers.POCKET_COMPUTER_NO_TERM.get() : Registry.ModContainers.POCKET_COMPUTER.get(), id, inventory,
             p -> {
                 ItemStack stack = p.getItemInHand( hand );
                 return stack.getItem() == item && ItemPocketComputer.getServerComputer( stack ) == computer;

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.IInventory;
+import net.minecraft.inventory.container.Slot;
+import net.minecraft.item.ItemStack;
+
+import javax.annotation.Nonnull;
+
+public class InvisibleSlot extends Slot
+{
+    public InvisibleSlot( IInventory container, int slot )
+    {
+        super( container, slot, 0, 0 );
+    }
+
+    @Override
+    public boolean mayPlace( @Nonnull ItemStack stack )
+    {
+        return false;
+    }
+
+    @Override
+    public boolean mayPickup( @Nonnull PlayerEntity player )
+    {
+        return false;
+    }
+
+    @Override
+    public boolean isActive()
+    {
+        return false;
+    }
+}