Paper/patches/server/1021-Item-serialization-as-json.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: masmc05 <masmc05@gmail.com>
Date: Sun, 11 Aug 2024 03:01:52 +0300
Subject: [PATCH] Item serialization as json


diff --git a/src/main/java/net/minecraft/world/item/component/CustomData.java b/src/main/java/net/minecraft/world/item/component/CustomData.java
index c80fd4960dfbb0fde37363e7df25b0a5411bdb11..ff7f6916f65466c25a7bde35d64682c15b211697 100644
--- a/src/main/java/net/minecraft/world/item/component/CustomData.java
+++ b/src/main/java/net/minecraft/world/item/component/CustomData.java
@@ -28,7 +28,17 @@ import org.slf4j.Logger;
 public final class CustomData {
     private static final Logger LOGGER = LogUtils.getLogger();
     public static final CustomData EMPTY = new CustomData(new CompoundTag());
-    public static final Codec<CustomData> CODEC = Codec.withAlternative(CompoundTag.CODEC, TagParser.AS_CODEC)
+    // Paper start - Item serialization as json
+    public static ThreadLocal<Boolean> SERIALIZE_CUSTOM_AS_SNBT = ThreadLocal.withInitial(() -> false);
+    public static final Codec<CustomData> CODEC = Codec.either(CompoundTag.CODEC, TagParser.AS_CODEC)
+        .xmap(com.mojang.datafixers.util.Either::unwrap, data -> { // Both will be used for deserialization, but we decide which one to use for serialization
+            if (!SERIALIZE_CUSTOM_AS_SNBT.get()) {
+                return com.mojang.datafixers.util.Either.left(data); // First codec
+            } else {
+                return com.mojang.datafixers.util.Either.right(data); // Second codec
+            }
+        })
+        // Paper end - Item serialization as json
         .xmap(CustomData::new, component -> component.tag);
     public static final Codec<CustomData> CODEC_WITH_ID = CODEC.validate(
         component -> component.getUnsafe().contains("id", 8) ? DataResult.success(component) : DataResult.error(() -> "Missing id for entity in: " + component)
diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
index 44c9127c71402afd6f98215b9e66fe5b848db50b..4c82dae4c2d764c8310832b1a209846d4352bae9 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -527,6 +527,39 @@ public final class CraftMagicNumbers implements UnsafeValues {
         return CraftItemStack.asCraftMirror(net.minecraft.world.item.ItemStack.parse(MinecraftServer.getServer().registryAccess(), compound).orElseThrow());
     }
 
+    @Override
+    public com.google.gson.JsonObject serializeItemAsJson(ItemStack itemStack) {
+        Preconditions.checkNotNull(itemStack, "Cannot serialize empty ItemStack");
+        Preconditions.checkArgument(!itemStack.isEmpty(), "Cannot serialize empty ItemStack");
+
+        net.minecraft.core.RegistryAccess.Frozen reg = net.minecraft.server.MinecraftServer.getServer().registryAccess();
+        com.mojang.serialization.DynamicOps<com.google.gson.JsonElement> ops = reg.createSerializationContext(com.mojang.serialization.JsonOps.INSTANCE);
+        com.google.gson.JsonObject item;
+        // Serialize as SNBT to preserve exact NBT types; vanilla codecs already can handle such deserialization.
+        net.minecraft.world.item.component.CustomData.SERIALIZE_CUSTOM_AS_SNBT.set(true);
+        try {
+            item = net.minecraft.world.item.ItemStack.CODEC.encodeStart(ops, CraftItemStack.unwrap(itemStack)).getOrThrow().getAsJsonObject();
+        } finally {
+            net.minecraft.world.item.component.CustomData.SERIALIZE_CUSTOM_AS_SNBT.set(false);
+        }
+        item.addProperty("DataVersion", this.getDataVersion());
+        return item;
+    }
+
+    @Override
+    public ItemStack deserializeItemFromJson(com.google.gson.JsonObject data) throws IllegalArgumentException {
+        Preconditions.checkNotNull(data, "null cannot be deserialized");
+
+        final int dataVersion = data.get("DataVersion").getAsInt();
+        final int currentVersion = org.bukkit.craftbukkit.util.CraftMagicNumbers.INSTANCE.getDataVersion();
+        data = ca.spottedleaf.dataconverter.minecraft.MCDataConverter.convertJson(
+            ca.spottedleaf.dataconverter.minecraft.datatypes.MCTypeRegistry.ITEM_STACK,
+            data, false, dataVersion, currentVersion
+        );
+        com.mojang.serialization.DynamicOps<com.google.gson.JsonElement> ops = MinecraftServer.getServer().registryAccess().createSerializationContext(com.mojang.serialization.JsonOps.INSTANCE);
+        return CraftItemStack.asCraftMirror(net.minecraft.world.item.ItemStack.CODEC.parse(ops, data).getOrThrow(IllegalArgumentException::new));
+    }
+
     @Override
     public byte[] serializeEntity(org.bukkit.entity.Entity entity) {
         Preconditions.checkNotNull(entity, "null cannot be serialized");