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 2b60572307e3ec23e21e09c34a04de9a1c57f136..150ab63f231fc3c39661ab876a8c90d608ee8568 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -469,6 +469,53 @@ public final class CraftMagicNumbers implements UnsafeValues {
     public com.destroystokyo.paper.util.VersionFetcher getVersionFetcher() {
         return new com.destroystokyo.paper.PaperVersionFetcher();
     }
+
+    @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((net.minecraft.nbt.CompoundTag) (item instanceof CraftItemStack ? ((CraftItemStack) item).handle : CraftItemStack.asNMSCopy(item)).save(MinecraftServer.getServer().registryAccess()));
+    }
+
+    @Override
+    public ItemStack deserializeItem(byte[] data) {
+        Preconditions.checkNotNull(data, "null cannot be deserialized");
+        Preconditions.checkArgument(data.length > 0, "cannot deserialize nothing");
+
+        net.minecraft.nbt.CompoundTag compound = deserializeNbtFromBytes(data);
+        final int dataVersion = compound.getInt("DataVersion");
+        compound = (net.minecraft.nbt.CompoundTag) MinecraftServer.getServer().fixerUpper.update(References.ITEM_STACK, new Dynamic<>(NbtOps.INSTANCE, compound), dataVersion, this.getDataVersion()).getValue();
+        return CraftItemStack.asCraftMirror(net.minecraft.world.item.ItemStack.parse(MinecraftServer.getServer().registryAccess(), compound).orElseThrow());
+    }
+
+    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 net.minecraft.nbt.CompoundTag deserializeNbtFromBytes(byte[] data) {
+        net.minecraft.nbt.CompoundTag compound;
+        try {
+            compound = net.minecraft.nbt.NbtIo.readCompressed(
+                new java.io.ByteArrayInputStream(data), net.minecraft.nbt.NbtAccounter.unlimitedHeap()
+            );
+        } 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
 
     /**