From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Mariell Hoversholm <proximyst@proximyst.com>
Date: Thu, 30 Apr 2020 16:56:54 +0200
Subject: [PATCH] Add Raw Byte ItemStack Serialization

Serializes using NBT which is safer for server data migrations than bukkits format.

diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
index 7fed3c5cbc48fb8de7af006720aa2a6fbe16c556..b38e0ac6a2eafc0d98bb81665bdc2eafbac2d7d8 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -431,6 +431,53 @@ public final class CraftMagicNumbers implements UnsafeValues {
     public boolean isSupportedApiVersion(String apiVersion) {
         return apiVersion != null && SUPPORTED_API.contains(apiVersion);
     }
+
+    @Override
+    public byte[] serializeItem(ItemStack item) {
+        Preconditions.checkNotNull(item, "null cannot be serialized");
+        Preconditions.checkArgument(item.getType() != Material.AIR, "air cannot be serialized");
+
+        return serializeNbtToBytes((item instanceof CraftItemStack ? ((CraftItemStack) item).handle : CraftItemStack.asNMSCopy(item)).save(new CompoundTag()));
+    }
+
+    @Override
+    public ItemStack deserializeItem(byte[] data) {
+        Preconditions.checkNotNull(data, "null cannot be deserialized");
+        Preconditions.checkArgument(data.length > 0, "cannot deserialize nothing");
+
+        CompoundTag compound = deserializeNbtFromBytes(data);
+        int dataVersion = compound.getInt("DataVersion");
+        Dynamic<Tag> converted = DataFixers.getDataFixer().update(References.ITEM_STACK, new Dynamic<Tag>(NbtOps.INSTANCE, compound), dataVersion, getDataVersion());
+        return CraftItemStack.asCraftMirror(net.minecraft.world.item.ItemStack.of((CompoundTag) converted.getValue()));
+    }
+
+    private byte[] serializeNbtToBytes(CompoundTag compound) {
+        compound.putInt("DataVersion", getDataVersion());
+        java.io.ByteArrayOutputStream outputStream = new java.io.ByteArrayOutputStream();
+        try {
+            net.minecraft.nbt.NbtIo.writeCompressed(
+                compound,
+                outputStream
+            );
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+        return outputStream.toByteArray();
+    }
+
+    private CompoundTag deserializeNbtFromBytes(byte[] data) {
+        CompoundTag compound;
+        try {
+            compound = net.minecraft.nbt.NbtIo.readCompressed(
+                new java.io.ByteArrayInputStream(data)
+            );
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+        int dataVersion = compound.getInt("DataVersion");
+        Preconditions.checkArgument(dataVersion <= getDataVersion(), "Newer version! Server downgrades are not supported!");
+        return compound;
+    }
     // Paper end
 
     /**