From 3fbe4af7bcafee200f8492e070b8ea2d98a00181 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 4 Jul 2018 02:10:36 -0400
Subject: [PATCH] Store reference to current Chunk for Entity and Block
 Entities

This enables us a fast reference to the entities current chunk instead
of having to look it up by hashmap lookups.

diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index 4bbebb25a..68008fe6a 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -25,7 +25,7 @@ public class Chunk {
     private final byte[] g;
     private final int[] h;
     private final boolean[] i;
-    private boolean j;
+    private boolean j; public boolean isLoaded() { return j; } // Paper - OBFHELPER
     public final World world;
     public final int[] heightMap;
     public final int locX;
@@ -33,6 +33,30 @@ public class Chunk {
     private boolean m;
     public final Map<BlockPosition, TileEntity> tileEntities;
     public final List<Entity>[] entitySlices; // Spigot
+    // Paper start
+    private class TileEntityHashMap extends java.util.HashMap<BlockPosition, TileEntity> {
+        @Override
+        public TileEntity put(BlockPosition key, TileEntity value) {
+            TileEntity replaced = super.put(key, value);
+            if (replaced != null) {
+                replaced.setCurrentChunk(null);
+            }
+            if (value != null) {
+                value.setCurrentChunk(Chunk.this);
+            }
+            return replaced;
+        }
+
+        @Override
+        public TileEntity remove(Object key) {
+            TileEntity removed = super.remove(key);
+            if (removed != null) {
+                removed.setCurrentChunk(null);
+            }
+            return removed;
+        }
+    }
+    // Paper end
     private boolean done;
     private boolean lit;
     private boolean r;
@@ -80,7 +104,7 @@ public class Chunk {
         this.g = new byte[256];
         this.h = new int[256];
         this.i = new boolean[256];
-        this.tileEntities = Maps.newHashMap();
+        this.tileEntities = new TileEntityHashMap(); // Paper
         this.x = 4096;
         this.y = Queues.newConcurrentLinkedQueue();
         this.entitySlices = (List[]) (new List[16]); // Spigot
@@ -624,6 +648,9 @@ public class Chunk {
                 this.entityCount.adjustOrPutValue( creatureType.a(), 1, 1 );
             }
         }
+        // Paper start
+        entity.setCurrentChunk(this);
+        // Paper end
         // Spigot end
     }
 
@@ -656,6 +683,9 @@ public class Chunk {
                 this.entityCount.adjustValue( creatureType.a(), -1 );
             }
         }
+        // Paper start
+        entity.setCurrentChunk(null);
+        // Paper end
         // Spigot end
     }
 
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 3a8902bf1..f7750a05c 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1703,6 +1703,19 @@ public abstract class Entity implements ICommandListener, KeyedObject { // Paper
     }
 
     // Paper start
+    private java.lang.ref.WeakReference<Chunk> currentChunk = null;
+    public Chunk getCurrentChunk() {
+        final Chunk chunk = currentChunk != null ? currentChunk.get() : null;
+        final int cx = getChunkX();
+        final int cz = getChunkZ();
+        if (chunk != null && chunk.isLoaded() && chunk.locX == cx && chunk.locZ == cz) {
+            return chunk;
+        }
+        return world.getChunkIfLoaded(cx, cz);
+    }
+    public void setCurrentChunk(Chunk chunk) {
+        this.currentChunk = chunk != null ? new java.lang.ref.WeakReference<>(chunk) : null;
+    }
     public final MinecraftKey entityKey = EntityTypes.getKey(this);
     public final String entityKeyString = entityKey != null ? entityKey.toString() : null;
 
diff --git a/src/main/java/net/minecraft/server/TileEntity.java b/src/main/java/net/minecraft/server/TileEntity.java
index 672ba3134..d7132c3c0 100644
--- a/src/main/java/net/minecraft/server/TileEntity.java
+++ b/src/main/java/net/minecraft/server/TileEntity.java
@@ -28,6 +28,14 @@ public abstract class TileEntity implements KeyedObject {
     }
 
     // Paper start
+    private java.lang.ref.WeakReference<Chunk> currentChunk = null;
+    public Chunk getCurrentChunk() {
+        final Chunk chunk = currentChunk != null ? currentChunk.get() : world.getChunkIfLoaded(position.getX() >> 4, position.getZ() >> 4);
+        return chunk != null && chunk.isLoaded() ? chunk : null;
+    }
+    public void setCurrentChunk(Chunk chunk) {
+        this.currentChunk = chunk != null ? new java.lang.ref.WeakReference<>(chunk) : null;
+    }
     public final MinecraftKey tileEntityKey = getKey(this.getClass());
     public final String tileEntityKeyString = tileEntityKey != null ? tileEntityKey.toString() : null;
 
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index c5a194ffe..833e3111d 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -9,6 +9,7 @@ import java.util.UUID;
 
 import net.minecraft.server.*;
 
+import org.bukkit.Chunk;
 import org.bukkit.EntityEffect;
 import org.bukkit.Location;
 import org.bukkit.Server;
@@ -39,6 +40,12 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         this.entity = entity;
     }
 
+    @Override
+    public Chunk getChunk() {
+        net.minecraft.server.Chunk currentChunk = entity.getCurrentChunk();
+        return currentChunk != null ? currentChunk.bukkitChunk : getLocation().getChunk();
+    }
+
     public static CraftEntity getEntity(CraftServer server, Entity entity) {
         /**
          * Order is *EXTREMELY* important -- keep it right! =D
-- 
2.18.0