From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Mariell Hoversholm <proximyst@proximyst.com>
Date: Sun, 24 Oct 2021 16:20:31 -0400
Subject: [PATCH] Add Raw Byte Entity Serialization


diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 296efe4970b1f0b6673e8e09ff0f6ac46e624c5f..445c292cbfd151148945f57ad8dd2f0a2481936f 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -1832,6 +1832,15 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, i
         }
     }
 
+    // Paper start - Entity serialization api
+    public boolean serializeEntity(CompoundTag compound) {
+        List<Entity> pass = new java.util.ArrayList<>(this.getPassengers());
+        this.passengers = ImmutableList.of();
+        boolean result = save(compound);
+        this.passengers = ImmutableList.copyOf(pass);
+        return result;
+    }
+    // Paper end
     public boolean save(CompoundTag nbt) {
         return this.isPassenger() ? false : this.saveAsPassenger(nbt);
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 49738cdb2f712d9ce76d3fff92b79e829bfa2370..788148145eddc90eac35881bc847e958b6a47ebe 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -1284,5 +1284,15 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         }
         return set;
     }
+
+    @Override
+    public boolean spawnAt(Location location, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason reason) {
+        Preconditions.checkNotNull(location, "location cannot be null");
+        Preconditions.checkNotNull(reason, "reason cannot be null");
+        entity.level = ((CraftWorld) location.getWorld()).getHandle();
+        entity.setPos(location.getX(), location.getY(), location.getZ());
+        entity.setRot(location.getYaw(), location.getPitch());
+        return !entity.valid && entity.level.addFreshEntity(entity, reason);
+    }
     // Paper end
 }
diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
index 42f70f0def442d636d83d315121451015b0d2fda..4be7b18b4e794734439d1e8bec4304d88328c91e 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -448,6 +448,30 @@ public final class CraftMagicNumbers implements UnsafeValues {
         return CraftItemStack.asCraftMirror(net.minecraft.world.item.ItemStack.of((CompoundTag) converted.getValue()));
     }
 
+    @Override
+    public byte[] serializeEntity(org.bukkit.entity.Entity entity) {
+        Preconditions.checkNotNull(entity, "null cannot be serialized");
+        Preconditions.checkArgument(entity instanceof org.bukkit.craftbukkit.entity.CraftEntity, "only CraftEntities can be serialized");
+
+        CompoundTag compound = new CompoundTag();
+        ((org.bukkit.craftbukkit.entity.CraftEntity) entity).getHandle().serializeEntity(compound);
+        return serializeNbtToBytes(compound);
+    }
+
+    @Override
+    public org.bukkit.entity.Entity deserializeEntity(byte[] data, org.bukkit.World world, boolean preserveUUID) {
+        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.ENTITY_TREE, new Dynamic<>(NbtOps.INSTANCE, compound), dataVersion, getDataVersion());
+        compound = (CompoundTag) converted.getValue();
+        if (!preserveUUID) compound.remove("UUID"); // Generate a new UUID so we don't have to worry about deserializing the same entity twice
+        return net.minecraft.world.entity.EntityType.create(compound, ((org.bukkit.craftbukkit.CraftWorld) world).getHandle())
+            .orElseThrow(() -> new IllegalArgumentException("An ID was not found for the data. Did you downgrade?")).getBukkitEntity();
+    }
+
     private byte[] serializeNbtToBytes(CompoundTag compound) {
         compound.putInt("DataVersion", getDataVersion());
         java.io.ByteArrayOutputStream outputStream = new java.io.ByteArrayOutputStream();
