Add RegisterCapabilitiesEvent (#8021)

src/main/java/net/minecraftforge/common/ForgeMod.java

@@ -33,6 +33,7 @@ import net.minecraft.world.level.storage.WorldData;
 import net.minecraft.world.level.storage.LevelStorageSource;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.client.ForgeHooksClient;
+import net.minecraftforge.common.capabilities.RegisterCapabilitiesEvent;
 import net.minecraftforge.common.data.ExistingFileHelper;
 import net.minecraftforge.common.data.ForgeFluidTagsProvider;
 import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
@@ -150,6 +151,7 @@ public class ForgeMod implements WorldPersistenceHooks.WorldPersistenceHook
         WorldPersistenceHooks.addHook(this);
         WorldPersistenceHooks.addHook(new FMLWorldPersistenceHook());
         final IEventBus modEventBus = FMLJavaModLoadingContext.get().getModEventBus();
+        modEventBus.addListener(this::registerCapabilities);
         modEventBus.addListener(this::preInit);
         modEventBus.addListener(this::gatherData);
         modEventBus.addListener(this::loadComplete);
@@ -171,13 +173,16 @@ public class ForgeMod implements WorldPersistenceHooks.WorldPersistenceHook
         BiomeDictionary.init();
     }
 
+    public void registerCapabilities(RegisterCapabilitiesEvent event)
+    {
+        CapabilityItemHandler.register(event);
+        CapabilityFluidHandler.register(event);
+        CapabilityAnimation.register(event);
+        CapabilityEnergy.register(event);
+    }
+
     public void preInit(FMLCommonSetupEvent evt)
     {
-        CapabilityItemHandler.register();
-        CapabilityFluidHandler.register();
-        CapabilityAnimation.register();
-        CapabilityEnergy.register();
-
         VersionChecker.startVersionCheck();
 
         registerArgumentTypes();

src/main/java/net/minecraftforge/common/capabilities/CapabilityManager.java

@@ -24,12 +24,12 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.IdentityHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
+import net.minecraftforge.fml.ModLoader;
 import net.minecraftforge.forgespi.language.ModFileScanData;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -43,7 +43,7 @@ import static net.minecraftforge.fml.Logging.CAPABILITIES;
 public enum CapabilityManager
 {
     INSTANCE;
-    private static final Logger LOGGER = LogManager.getLogger();
+    static final Logger LOGGER = LogManager.getLogger();
     private static final Type CAP_INJECT = Type.getType(CapabilityInject.class);
 
     /**
@@ -53,7 +53,9 @@ public enum CapabilityManager
      * This method is safe to call during parallel mod loading.
      *
      * @param type The class type to be registered
+     * @deprecated use {@link RegisterCapabilitiesEvent}
      */
+    @Deprecated(forRemoval = true)
     public <T> void register(Class<T> type)
     {
         Objects.requireNonNull(type,"Attempted to register a capability with invalid type");
@@ -71,7 +73,7 @@ public enum CapabilityManager
             providers.put(realName, cap);
         }
 
-        callbacks.getOrDefault(realName, Collections.emptyList()).forEach(func -> func.apply(cap));
+        fireCallbacks(this.callbacks, List.of(cap));
     }
 
     // INTERNAL
@@ -79,21 +81,36 @@ public enum CapabilityManager
     private volatile IdentityHashMap<String, List<Function<Capability<?>, Object>>> callbacks;
     public void injectCapabilities(List<ModFileScanData> data)
     {
-        final List<ModFileScanData.AnnotationData> capabilities = data.stream()
+        final List<ModFileScanData.AnnotationData> elementsToInject = data.stream()
             .map(ModFileScanData::getAnnotations)
             .flatMap(Collection::stream)
             .filter(a -> CAP_INJECT.equals(a.annotationType()))
             .collect(Collectors.toList());
-        final IdentityHashMap<String, List<Function<Capability<?>, Object>>> m = new IdentityHashMap<>();
-        capabilities.forEach(entry -> attachCapabilityToMethod(m, entry));
-        callbacks = m;
+        final IdentityHashMap<String, List<Function<Capability<?>, Object>>> callbacks = new IdentityHashMap<>();
+        elementsToInject.forEach(entry -> gatherCallbacks(callbacks, entry));
+
+        var event = new RegisterCapabilitiesEvent();
+        ModLoader.get().postEvent(event);
+        fireCallbacks(callbacks, event.getCapabilities().values());
+
+        // TODO 1.18: remove these fields
+        this.providers.putAll(event.getCapabilities());
+        this.callbacks = callbacks;
     }
 
-    private static void attachCapabilityToMethod(Map<String, List<Function<Capability<?>, Object>>> cbs, ModFileScanData.AnnotationData entry)
+    private static void fireCallbacks(Map<String, List<Function<Capability<?>, Object>>> callbacks, Iterable<Capability<?>> caps)
     {
-        final String targetClass = entry.clazz().getClassName();
-        final String targetName = entry.memberName();
-        Type type = (Type)entry.annotationData().get("value");
+        for (var cap : caps)
+        {
+            callbacks.getOrDefault(cap.getName(), List.of()).forEach(f -> f.apply(cap));
+        }
+    }
+
+    private static void gatherCallbacks(Map<String, List<Function<Capability<?>, Object>>> callbacks, ModFileScanData.AnnotationData annotationData)
+    {
+        final String targetClass = annotationData.clazz().getClassName();
+        final String targetName = annotationData.memberName();
+        Type type = (Type)annotationData.annotationData().get("value");
         if (type == null)
         {
             LOGGER.warn(CAPABILITIES,"Unable to inject capability at {}.{} (Invalid Annotation)", targetClass, targetName);
@@ -101,9 +118,9 @@ public enum CapabilityManager
         }
         final String capabilityName = type.getInternalName().replace('/', '.').intern();
 
-        List<Function<Capability<?>, Object>> list = cbs.computeIfAbsent(capabilityName, k -> new ArrayList<>());
+        List<Function<Capability<?>, Object>> list = callbacks.computeIfAbsent(capabilityName, k -> new ArrayList<>());
 
-        if (entry.memberName().indexOf('(') > 0)
+        if (annotationData.memberName().indexOf('(') > 0)
         {
             list.add(input -> {
                 try

src/main/java/net/minecraftforge/common/capabilities/RegisterCapabilitiesEvent.java

@@ -0,0 +1,60 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016-2021.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.common.capabilities;
+
+import net.minecraftforge.eventbus.api.Event;
+import net.minecraftforge.fml.event.IModBusEvent;
+
+import java.util.*;
+
+import static net.minecraftforge.fml.Logging.CAPABILITIES;
+
+/**
+ * This event fires when it is time to register your capabilities.
+ * @see Capability
+ */
+public final class RegisterCapabilitiesEvent extends Event implements IModBusEvent
+{
+
+    private final IdentityHashMap<String, Capability<?>> capabilities = new IdentityHashMap<>();
+
+    /**
+     * Registers a capability to be consumed by others.
+     * APIs who define the capability should call this.
+     * To retrieve the Capability instance, use the @CapabilityInject annotation.
+     *
+     * @param type The type to be registered
+     */
+    public <T> void register(Class<T> type)
+    {
+        Objects.requireNonNull(type,"Attempted to register a capability with invalid type");
+        String realName = type.getName().intern();
+        if (capabilities.putIfAbsent(realName, new Capability<>(realName)) != null) {
+            CapabilityManager.LOGGER.error(CAPABILITIES, "Cannot register capability implementation multiple times : {}", realName);
+            throw new IllegalArgumentException("Cannot register a capability implementation multiple times : "+ realName);
+        }
+    }
+
+    IdentityHashMap<String, Capability<?>> getCapabilities()
+    {
+        return this.capabilities;
+    }
+
+}

src/main/java/net/minecraftforge/common/model/animation/CapabilityAnimation.java

@@ -19,11 +19,10 @@
 
 package net.minecraftforge.common.model.animation;
 
-import net.minecraft.nbt.Tag;
 import net.minecraft.core.Direction;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.capabilities.CapabilityInject;
-import net.minecraftforge.common.capabilities.CapabilityManager;
+import net.minecraftforge.common.capabilities.RegisterCapabilitiesEvent;
 import net.minecraftforge.common.capabilities.ICapabilityProvider;
 import net.minecraftforge.common.util.LazyOptional;
 
@@ -35,9 +34,9 @@ public class CapabilityAnimation
     @CapabilityInject(IAnimationStateMachine.class)
     public static Capability<IAnimationStateMachine> ANIMATION_CAPABILITY = null;
 
-    public static void register()
+    public static void register(RegisterCapabilitiesEvent event)
     {
-        CapabilityManager.INSTANCE.register(IAnimationStateMachine.class);
+        event.register(IAnimationStateMachine.class);
     }
 
     public static class DefaultItemAnimationCapabilityProvider implements ICapabilityProvider

src/main/java/net/minecraftforge/energy/CapabilityEnergy.java

@@ -26,8 +26,8 @@ public class CapabilityEnergy
     @CapabilityInject(IEnergyStorage.class)
     public static Capability<IEnergyStorage> ENERGY = null;
 
-    public static void register()
+    public static void register(RegisterCapabilitiesEvent event)
     {
-        CapabilityManager.INSTANCE.register(IEnergyStorage.class);
+        event.register(IEnergyStorage.class);
     }
 }

src/main/java/net/minecraftforge/fluids/capability/CapabilityFluidHandler.java

@@ -21,7 +21,7 @@ package net.minecraftforge.fluids.capability;
 
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.capabilities.CapabilityInject;
-import net.minecraftforge.common.capabilities.CapabilityManager;
+import net.minecraftforge.common.capabilities.RegisterCapabilitiesEvent;
 
 public class CapabilityFluidHandler
 {
@@ -30,10 +30,10 @@ public class CapabilityFluidHandler
     @CapabilityInject(IFluidHandlerItem.class)
     public static Capability<IFluidHandlerItem> FLUID_HANDLER_ITEM_CAPABILITY = null;
 
-    public static void register()
+    public static void register(RegisterCapabilitiesEvent event)
     {
-        CapabilityManager.INSTANCE.register(IFluidHandler.class);
+        event.register(IFluidHandler.class);
 
-        CapabilityManager.INSTANCE.register(IFluidHandlerItem.class);
+        event.register(IFluidHandlerItem.class);
     }
 }

src/main/java/net/minecraftforge/items/CapabilityItemHandler.java

@@ -21,16 +21,16 @@ package net.minecraftforge.items;
 
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.capabilities.CapabilityInject;
-import net.minecraftforge.common.capabilities.CapabilityManager;
+import net.minecraftforge.common.capabilities.RegisterCapabilitiesEvent;
 
 public class CapabilityItemHandler
 {
     @CapabilityInject(IItemHandler.class)
     public static Capability<IItemHandler> ITEM_HANDLER_CAPABILITY = null;
 
-    public static void register()
+    public static void register(RegisterCapabilitiesEvent event)
     {
-        CapabilityManager.INSTANCE.register(IItemHandler.class);
+        event.register(IItemHandler.class);
     }
 
 }