Add dataprovider for Global Loot Modifiers (#6960)

src/main/java/net/minecraftforge/common/data/GlobalLootModifierProvider.java

@@ -0,0 +1,119 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016-2020.
+ *
+ * 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.data;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonObject;
+import cpw.mods.modlauncher.api.LamdbaExceptionUtils;
+import net.minecraft.data.DataGenerator;
+import net.minecraft.data.DirectoryCache;
+import net.minecraft.data.IDataProvider;
+import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.Tuple;
+import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
+import net.minecraftforge.common.loot.IGlobalLootModifier;
+import net.minecraftforge.common.loot.LootModifier;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Provider for forge's GlobalLootModifier system. See {@link LootModifier} and {@link GlobalLootModifierSerializer}.
+ *
+ * This provider only requires implementing {@link #start()} and calling {@link #add} from it.
+ */
+public abstract class GlobalLootModifierProvider implements IDataProvider
+{
+    private static final Gson GSON = new GsonBuilder().setPrettyPrinting().create();
+    private final DataGenerator gen;
+    private final String modid;
+    private final Map<String, Tuple<GlobalLootModifierSerializer<?>, JsonObject>> toSerialize = new HashMap<>();
+    private boolean replace = false;
+
+    public GlobalLootModifierProvider(DataGenerator gen, String modid)
+    {
+        this.gen = gen;
+        this.modid = modid;
+    }
+
+    /**
+     * Sets the "replace" key in global_loot_modifiers to true.
+     */
+    protected void replacing()
+    {
+        this.replace = true;
+    }
+
+    /**
+     * Call {@link #add} here, which will pass in the necessary information to write the jsons.
+     */
+    protected abstract void start();
+
+    @Override
+    public void act(DirectoryCache cache) throws IOException
+    {
+        start();
+
+        Path forgePath = gen.getOutputFolder().resolve("data/forge/loot_modifiers/global_loot_modifiers.json");
+        String modPath = "data/" + modid + "/loot_modifiers/";
+        List<ResourceLocation> entries = new ArrayList<>();
+
+        toSerialize.forEach(LamdbaExceptionUtils.rethrowBiConsumer((name, pair) ->
+        {
+            entries.add(new ResourceLocation(modid, name));
+            Path modifierPath = gen.getOutputFolder().resolve(modPath + name + ".json");
+
+            JsonObject json = pair.getB();
+            json.addProperty("type", pair.getA().getRegistryName().toString());
+
+            IDataProvider.save(GSON, cache, json, modifierPath);
+        }));
+
+        JsonObject forgeJson = new JsonObject();
+        forgeJson.addProperty("replace", this.replace);
+        forgeJson.add("entries", GSON.toJsonTree(entries.stream().map(ResourceLocation::toString).collect(Collectors.toList())));
+
+        IDataProvider.save(GSON, cache, forgeJson, forgePath);
+    }
+
+    /**
+     * Passes in the data needed to create the file without any extra objects.
+     *
+     * @param modifier      The name of the modifier, which will be the file name.
+     * @param serializer    The serializer of this modifier.
+     * @param conditions    The loot conditions before {@link LootModifier#doApply} is called.
+     */
+    public <T extends IGlobalLootModifier> void add(String modifier, GlobalLootModifierSerializer<T> serializer, T instance)
+    {
+        this.toSerialize.put(modifier, new Tuple<>(serializer, serializer.write(instance)));
+    }
+
+    @Override
+    public String getName()
+    {
+        return "Global Loot Modifiers : " + modid;
+    }
+}

src/main/java/net/minecraftforge/common/loot/GlobalLootModifierSerializer.java

@@ -21,6 +21,7 @@ package net.minecraftforge.common.loot;
 
 import com.google.gson.JsonObject;
 
+import net.minecraft.loot.ConditionArraySerializer;
 import net.minecraft.loot.conditions.ILootCondition;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.registries.GameData;
@@ -64,6 +65,24 @@ public abstract class GlobalLootModifierSerializer<T extends IGlobalLootModifier
      */
     public abstract T read(ResourceLocation location, JsonObject object, ILootCondition[] ailootcondition);
 
+    /**
+     * Write the serializer to json.
+     *
+     * Most serializers won't have to do anything else than {@link #makeConditions}
+     * Which simply creates the JsonObject from an array of ILootConditions.
+     */
+    public abstract JsonObject write(T instance);
+
+    /**
+     * Helper to create the json object from the conditions.
+     * Add any extra properties to the returned json.
+     */
+    public JsonObject makeConditions(ILootCondition[] conditions) {
+        JsonObject json = new JsonObject();
+        json.add("conditions", ConditionArraySerializer.field_235679_a_.func_235681_a_(conditions));
+        return json;
+    }
+
     /**
      * Used by Forge's registry system.
      */