Access capabilities using PlatformHelper

We provide a new abstraction: ComponentAccess, which is a view of
capabilities (or block lookups for Fabric) for adjacent blocks.

build.gradle.kts

@@ -111,7 +111,8 @@ minecraft {
             mods.register("cctest") {
                 source(sourceSets["testMod"])
                 source(sourceSets["testFixtures"])
-                // FIXME: We need this for running in-dev but not from Gradle: source(project(":core").sourceSets.testFixtures.get())
+                // FIXME: We need this for running in-dev but not from Gradle:
+                // source(project(":core").sourceSets.testFixtures.get())
             }
         }
 

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

@@ -11,11 +11,11 @@
 import net.minecraft.client.gui.screens.Screen;
 import net.minecraft.network.chat.Component;
 import net.minecraft.resources.ResourceLocation;
-import net.minecraftforge.common.util.NonNullSupplier;
 
 import javax.annotation.Nonnull;
 import java.util.List;
 import java.util.function.IntSupplier;
+import java.util.function.Supplier;
 
 /**
  * Version of {@link net.minecraft.client.gui.components.ImageButton} which allows changing some properties
@@ -29,7 +29,7 @@ public class DynamicImageButton extends Button {
     private final int yDiffTex;
     private final int textureWidth;
     private final int textureHeight;
-    private final NonNullSupplier<List<Component>> tooltip;
+    private final Supplier<List<Component>> tooltip;
 
     public DynamicImageButton(
         Screen screen, int x, int y, int width, int height, int xTexStart, int yTexStart, int yDiffTex,
@@ -47,7 +47,7 @@ public DynamicImageButton(
     public DynamicImageButton(
         Screen screen, int x, int y, int width, int height, IntSupplier xTexStart, int yTexStart, int yDiffTex,
         ResourceLocation texture, int textureWidth, int textureHeight,
-        OnPress onPress, NonNullSupplier<List<Component>> tooltip
+        OnPress onPress, Supplier<List<Component>> tooltip
     ) {
         super(x, y, width, height, Component.empty(), onPress);
         this.screen = screen;

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

@@ -5,25 +5,28 @@
  */
 package dan200.computercraft.shared.computer.blocks;
 
+import com.google.common.base.Strings;
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.BundledRedstone;
-import dan200.computercraft.shared.Peripherals;
 import dan200.computercraft.shared.common.TileGeneric;
 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.core.ServerContext;
 import dan200.computercraft.shared.network.container.ComputerContainerData;
+import dan200.computercraft.shared.platform.ComponentAccess;
+import dan200.computercraft.shared.platform.PlatformHelper;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.IDAssigner;
 import dan200.computercraft.shared.util.RedstoneUtil;
-import joptsimple.internal.Strings;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.*;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.ItemStack;
@@ -32,7 +35,6 @@
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.phys.BlockHitResult;
-import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -51,7 +53,7 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
     private boolean fresh = false;
 
     private int invalidSides = 0;
-    private final NonNullConsumer<Object>[] invalidate;
+    private final ComponentAccess<IPeripheral> peripherals = PlatformHelper.get().createPeripheralAccess(d -> invalidSides |= 1 << d.ordinal());
 
     private LockCode lockCode = LockCode.NO_LOCK;
 
@@ -60,14 +62,6 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
     public TileComputerBase(BlockEntityType<? extends TileGeneric> type, BlockPos pos, BlockState state, ComputerFamily family) {
         super(type, pos, state);
         this.family = family;
-
-        // We cache these so we can guarantee we only ever register one listener for adjacent capabilities.
-        @SuppressWarnings({ "unchecked", "rawtypes" })
-        var invalidate = this.invalidate = new NonNullConsumer[6];
-        for (var direction : Direction.values()) {
-            var mask = 1 << direction.ordinal();
-            invalidate[direction.ordinal()] = o -> invalidSides |= mask;
-        }
     }
 
     protected void unload() {
@@ -231,8 +225,7 @@ private void refreshPeripheral(@Nonnull ServerComputer computer, Direction dir)
         var localDir = remapToLocalSide(dir);
         if (isPeripheralBlockedOnSide(localDir)) return;
 
-        var offsetSide = dir.getOpposite();
+        var peripheral = peripherals.get((ServerLevel) getLevel(), getBlockPos(), dir);
-        var peripheral = Peripherals.getPeripheral(getLevel(), getBlockPos().relative(dir), offsetSide, invalidate[dir.ordinal()]);
         computer.setPeripheral(localDir, peripheral);
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/BlockCable.java

@@ -6,9 +6,9 @@
 package dan200.computercraft.shared.peripheral.modem.wired;
 
 import com.google.common.collect.ImmutableMap;
-import dan200.computercraft.api.ForgeComputerCraftAPI;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.common.BlockGeneric;
+import dan200.computercraft.shared.platform.PlatformHelper;
 import dan200.computercraft.shared.util.WaterloggableHelpers;
 import dan200.computercraft.shared.util.WorldUtil;
 import net.minecraft.core.BlockPos;
@@ -76,10 +76,10 @@ public static boolean canConnectIn(BlockState state, Direction direction) {
         return state.getValue(BlockCable.CABLE) && state.getValue(BlockCable.MODEM).getFacing() != direction;
     }
 
-    public static boolean doesConnectVisually(BlockState state, BlockGetter world, BlockPos pos, Direction direction) {
+    public static boolean doesConnectVisually(BlockState state, Level level, BlockPos pos, Direction direction) {
         if (!state.getValue(CABLE)) return false;
         if (state.getValue(MODEM).getFacing() == direction) return true;
-        return ForgeComputerCraftAPI.getWiredElementAt(world, pos.relative(direction), direction.getOpposite()).isPresent();
+        return PlatformHelper.get().hasWiredElementIn(level, pos, direction);
     }
 
     @Nonnull
@@ -171,7 +171,7 @@ public BlockState updateShape(@Nonnull BlockState state, @Nonnull Direction side
             return getFluidState(state).createLegacyBlock();
         }
 
-        return state.setValue(CONNECTIONS.get(side), doesConnectVisually(state, world, pos, side));
+        return world instanceof Level level ? state.setValue(CONNECTIONS.get(side), doesConnectVisually(state, level, pos, side)) : state;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/TileCable.java

@@ -6,7 +6,6 @@
 package dan200.computercraft.shared.peripheral.modem.wired;
 
 import com.google.common.base.Objects;
-import dan200.computercraft.api.ForgeComputerCraftAPI;
 import dan200.computercraft.api.network.wired.IWiredElement;
 import dan200.computercraft.api.network.wired.IWiredNode;
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -14,12 +13,15 @@
 import dan200.computercraft.shared.command.text.ChatHelpers;
 import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
+import dan200.computercraft.shared.platform.ComponentAccess;
+import dan200.computercraft.shared.platform.PlatformHelper;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.TickScheduler;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.InteractionHand;
 import net.minecraft.world.InteractionResult;
 import net.minecraft.world.entity.player.Player;
@@ -30,8 +32,6 @@
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.phys.BlockHitResult;
 import net.minecraft.world.phys.Vec3;
-import net.minecraftforge.common.util.LazyOptional;
-import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -99,7 +99,7 @@ public Object getTarget() {
         }
     };
 
-    private final NonNullConsumer<LazyOptional<IWiredElement>> connectedNodeChanged = x -> connectionsChanged();
+    private final ComponentAccess<IWiredElement> connectedElements = PlatformHelper.get().createWiredElementAccess(x -> connectionsChanged());
 
     public TileCable(BlockEntityType<? extends TileCable> type, BlockPos pos, BlockState state) {
         super(type, pos, state);
@@ -284,11 +284,10 @@ void connectionsChanged() {
             var offset = current.relative(facing);
             if (!world.isLoaded(offset)) continue;
 
-            var element = ForgeComputerCraftAPI.getWiredElementAt(world, offset, facing.getOpposite());
+            var element = connectedElements.get((ServerLevel) world, current, facing);
-            if (!element.isPresent()) continue;
+            if (element == null) continue;
 
-            element.addListener(connectedNodeChanged);
+            var node = element.getNode();
-            var node = element.orElseThrow(NullPointerException::new).getNode();
             if (BlockCable.canConnectIn(state, facing)) {
                 // If we can connect to it then do so
                 this.node.connectTo(node);

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/TileWiredModemFull.java

@@ -6,19 +6,21 @@
 package dan200.computercraft.shared.peripheral.modem.wired;
 
 import com.google.common.base.Objects;
-import dan200.computercraft.api.ForgeComputerCraftAPI;
 import dan200.computercraft.api.network.wired.IWiredElement;
 import dan200.computercraft.api.network.wired.IWiredNode;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.shared.command.text.ChatHelpers;
 import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
+import dan200.computercraft.shared.platform.ComponentAccess;
+import dan200.computercraft.shared.platform.PlatformHelper;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.TickScheduler;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.InteractionHand;
 import net.minecraft.world.InteractionResult;
 import net.minecraft.world.entity.player.Player;
@@ -27,8 +29,6 @@
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.phys.BlockHitResult;
 import net.minecraft.world.phys.Vec3;
-import net.minecraftforge.common.util.LazyOptional;
-import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -89,7 +89,7 @@ public Vec3 getPosition() {
     private final WiredModemElement element = new FullElement(this);
     private final IWiredNode node = element.getNode();
 
-    private final NonNullConsumer<LazyOptional<IWiredElement>> connectedNodeChanged = x -> connectionsChanged();
+    private final ComponentAccess<IWiredElement> connectedElements = PlatformHelper.get().createWiredElementAccess(x -> connectionsChanged());
 
     private int invalidSides = 0;
 
@@ -252,11 +252,10 @@ private void connectionsChanged() {
             var offset = current.relative(facing);
             if (!world.isLoaded(offset)) continue;
 
-            var element = ForgeComputerCraftAPI.getWiredElementAt(world, offset, facing.getOpposite());
+            var element = connectedElements.get((ServerLevel) getLevel(), getBlockPos(), facing);
-            if (!element.isPresent()) continue;
+            if (element == null) return;
 
-            element.addListener(connectedNodeChanged);
+            node.connectTo(element.getNode());
-            node.connectTo(element.orElseThrow(NullPointerException::new).getNode());
         }
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/WiredModemLocalPeripheral.java

@@ -7,14 +7,15 @@
 
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.shared.ModRegistry;
-import dan200.computercraft.shared.Peripherals;
 import dan200.computercraft.shared.computer.core.ServerContext;
+import dan200.computercraft.shared.platform.ComponentAccess;
+import dan200.computercraft.shared.platform.PlatformHelper;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.Tag;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.level.Level;
-import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -35,10 +36,10 @@ public final class WiredModemLocalPeripheral {
     private String type;
 
     private IPeripheral peripheral;
-    private final NonNullConsumer<Object> invalidate;
+    private final ComponentAccess<IPeripheral> peripherals;
 
     public WiredModemLocalPeripheral(@Nonnull Runnable invalidate) {
-        this.invalidate = x -> invalidate.run();
+        peripherals = PlatformHelper.get().createPeripheralAccess(x -> invalidate.run());
     }
 
     /**
@@ -126,7 +127,7 @@ private IPeripheral getPeripheralFrom(Level world, BlockPos pos, Direction direc
         var block = world.getBlockState(offset).getBlock();
         if (block == ModRegistry.Blocks.WIRED_MODEM_FULL.get() || block == ModRegistry.Blocks.CABLE.get()) return null;
 
-        var peripheral = Peripherals.getPeripheral(world, offset, direction.getOpposite(), invalidate);
+        var peripheral = peripherals.get((ServerLevel) world, pos, direction);
         return peripheral instanceof WiredModemPeripheral ? null : peripheral;
     }
 }

src/main/java/dan200/computercraft/shared/platform/ComponentAccess.java

@@ -0,0 +1,33 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.platform;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.server.level.ServerLevel;
+
+import javax.annotation.Nullable;
+
+/**
+ * A (possibly cached) provider of a component at a specific location.
+ *
+ * @param <T> The type of the component.
+ */
+public interface ComponentAccess<T> {
+    /**
+     * Get a peripheral for the current block.
+     * <p>
+     * Both {@code level} and {@code pos} must be constant for the lifetime of the store.
+     *
+     * @param level     The current level.
+     * @param pos       The position of the block fetching the peripheral, for instance the computer or modem.
+     * @param direction The direction the peripheral is in.
+     * @return The peripheral, or {@literal null} if not found.
+     * @throws IllegalStateException If the level or position have changed.
+     */
+    @Nullable
+    T get(ServerLevel level, BlockPos pos, Direction direction);
+}

src/main/java/dan200/computercraft/shared/platform/PlatformHelper.java

@@ -5,10 +5,13 @@
  */
 package dan200.computercraft.shared.platform;
 
+import dan200.computercraft.api.network.wired.IWiredElement;
+import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.shared.network.NetworkMessage;
 import dan200.computercraft.shared.network.client.ClientNetworkContext;
 import dan200.computercraft.shared.network.container.ContainerData;
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
 import net.minecraft.core.Registry;
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.resources.ResourceKey;
@@ -20,6 +23,7 @@
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.AbstractContainerMenu;
 import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntityType;
@@ -30,6 +34,7 @@
 import javax.annotation.Nullable;
 import java.util.Collection;
 import java.util.function.BiFunction;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 /**
@@ -146,4 +151,34 @@ static PlatformHelper get() {
      * @param chunk   The chunk players must be tracking.
      */
     void sendToAllTracking(NetworkMessage<ClientNetworkContext> message, LevelChunk chunk);
+
+    /**
+     * Create a {@link ComponentAccess} for surrounding peripherals.
+     *
+     * @param invalidate The function to call when a neighbouring peripheral potentially changes. This <em>MAY NOT</em>
+     *                   include all changes, and so block updates should still be listened to.
+     * @return The peripheral component access.
+     */
+    ComponentAccess<IPeripheral> createPeripheralAccess(Consumer<Direction> invalidate);
+
+    /**
+     * Create a {@link ComponentAccess} for surrounding wired nodes.
+     *
+     * @param invalidate The function to call when a neighbouring wired node potentially changes. This <em>MAY NOT</em>
+     *                   include all changes, and so block updates should still be listened to.
+     * @return The peripheral component access.
+     */
+    ComponentAccess<IWiredElement> createWiredElementAccess(Consumer<Direction> invalidate);
+
+    /**
+     * Determine if there is a wired element in the given direction. This is equivalent to
+     * {@code createWiredElementAt(x -> {}).get(level, pos, dir) != null}, but is intended for when we don't need the
+     * cache.
+     *
+     * @param level     The current level.
+     * @param pos       The <em>current</em> block's position.
+     * @param direction The direction to check in.
+     * @return Whether there is a wired element in the given direction.
+     */
+    boolean hasWiredElementIn(Level level, BlockPos pos, Direction direction);
 }

src/main/java/dan200/computercraft/shared/platform/PlatformHelperImpl.java

@@ -7,10 +7,16 @@
 
 import com.google.auto.service.AutoService;
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.network.wired.IWiredElement;
+import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.shared.Capabilities;
+import dan200.computercraft.shared.Peripherals;
 import dan200.computercraft.shared.network.NetworkMessage;
 import dan200.computercraft.shared.network.client.ClientNetworkContext;
 import dan200.computercraft.shared.network.container.ContainerData;
+import dan200.computercraft.shared.util.CapabilityUtil;
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
 import net.minecraft.core.Registry;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.FriendlyByteBuf;
@@ -24,13 +30,16 @@
 import net.minecraft.world.inventory.AbstractContainerMenu;
 import net.minecraft.world.inventory.MenuType;
 import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.phys.Vec3;
+import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.extensions.IForgeMenuType;
+import net.minecraftforge.common.util.NonNullConsumer;
 import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
 import net.minecraftforge.network.NetworkHooks;
 import net.minecraftforge.registries.DeferredRegister;
@@ -43,6 +52,7 @@
 import java.util.Iterator;
 import java.util.Set;
 import java.util.function.BiFunction;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
 
@@ -118,6 +128,24 @@ public void sendToAllTracking(NetworkMessage<ClientNetworkContext> message, Leve
         NetworkHandler.sendToAllTracking(message, chunk);
     }
 
+    @Override
+    public ComponentAccess<IPeripheral> createPeripheralAccess(Consumer<Direction> invalidate) {
+        return new PeripheralAccess(invalidate);
+    }
+
+    @Override
+    public ComponentAccess<IWiredElement> createWiredElementAccess(Consumer<Direction> invalidate) {
+        return new CapabilityAccess<>(Capabilities.CAPABILITY_WIRED_ELEMENT, invalidate);
+    }
+
+    @Override
+    public boolean hasWiredElementIn(Level level, BlockPos pos, Direction direction) {
+        if (!level.isLoaded(pos)) return false;
+
+        var blockEntity = level.getBlockEntity(pos.relative(direction));
+        return blockEntity != null && blockEntity.getCapability(Capabilities.CAPABILITY_WIRED_ELEMENT, direction.getOpposite()).isPresent();
+    }
+
     @Nullable
     @Override
     public CompoundTag getShareTag(ItemStack item) {
@@ -190,4 +218,62 @@ public T get() {
             return object.get();
         }
     }
+
+    private abstract static class ComponentAccessImpl<T> implements ComponentAccess<T> {
+        private final NonNullConsumer<Object>[] invalidators;
+        private @Nullable Level level;
+        private @Nullable BlockPos pos;
+
+        ComponentAccessImpl(Consumer<Direction> invalidate) {
+            // Generate a cache of invalidation functions so we can guarantee we only ever have one registered per
+            // capability - there's no way to remove these callbacks!
+            @SuppressWarnings({ "unchecked", "rawtypes" })
+            var invalidators = this.invalidators = new NonNullConsumer[6];
+            for (var dir : Direction.values()) invalidators[dir.ordinal()] = x -> invalidate.accept(dir);
+        }
+
+        @Nullable
+        protected abstract T get(ServerLevel world, BlockPos pos, Direction side, NonNullConsumer<Object> invalidate);
+
+        @Nullable
+        @Override
+        public T get(ServerLevel level, BlockPos pos, Direction direction) {
+            if (this.level != null && this.level != level) throw new IllegalStateException("Level has changed");
+            if (this.pos != null && this.pos != pos) throw new IllegalStateException("Position has changed");
+
+            this.level = level;
+            this.pos = pos;
+            return get(level, pos.relative(direction), direction.getOpposite(), invalidators[direction.ordinal()]);
+        }
+    }
+
+    private static class PeripheralAccess extends ComponentAccessImpl<IPeripheral> {
+        PeripheralAccess(Consumer<Direction> invalidate) {
+            super(invalidate);
+        }
+
+        @Nullable
+        @Override
+        protected IPeripheral get(ServerLevel world, BlockPos pos, Direction side, NonNullConsumer<Object> invalidate) {
+            return Peripherals.getPeripheral(world, pos, side, invalidate);
+        }
+    }
+
+    private static class CapabilityAccess<T> extends ComponentAccessImpl<T> {
+        private final Capability<T> capability;
+
+        CapabilityAccess(Capability<T> capability, Consumer<Direction> invalidate) {
+            super(invalidate);
+            this.capability = capability;
+        }
+
+        @Nullable
+        @Override
+        protected T get(ServerLevel world, BlockPos pos, Direction side, NonNullConsumer<Object> invalidate) {
+            if (!world.isLoaded(pos)) return null;
+
+            var blockEntity = world.getBlockEntity(pos);
+            return blockEntity != null ? CapabilityUtil.unwrap(blockEntity.getCapability(capability, side), invalidate) : null;
+        }
+    }
 }