From 228ece2e9442e9f318bbfc5fc33262d1f0192f3a Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Fri, 31 Jan 2014 11:18:34 -0500
Subject: [PATCH] Cap Entity Collisions

Limit a single entity to colliding a max of configurable times per tick.
This will alleviate issues where living entities are hoarded in 1x1 pens.

diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index fd7c615..d6c8be8 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1060,6 +1060,7 @@ public abstract class Entity implements ICommandListener {
 
     public void d(EntityHuman entityhuman) {}
 
+    int numCollisions = 0; // Spigot
     public void collide(Entity entity) {
         if (entity.passenger != this && entity.vehicle != this) {
             if (!entity.T && !this.T) {
diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 6358f5e..9604034 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -1617,7 +1617,9 @@ public abstract class EntityLiving extends Entity {
         List list = this.world.getEntities(this, this.getBoundingBox().grow(0.20000000298023224D, 0.0D, 0.20000000298023224D));
 
         if (this.ad() && list != null && !list.isEmpty()) { // Spigot: Add this.ad() condition
+            numCollisions -= world.spigotConfig.maxCollisionsPerEntity; // Spigot
             for (int i = 0; i < list.size(); ++i) {
+                if (numCollisions > world.spigotConfig.maxCollisionsPerEntity) { break; } // Spigot
                 Entity entity = (Entity) list.get(i);
                 
                 // TODO better check now?
@@ -1628,9 +1630,12 @@ public abstract class EntityLiving extends Entity {
                 // CraftBukkit end
 
                 if (entity.ae()) {
+                    entity.numCollisions++; // Spigot
+                    numCollisions++; // Spigot
                     this.s(entity);
                 }
             }
+            numCollisions = 0; // Spigot
         }
 
     }
diff --git a/src/main/java/org/spigotmc/SpigotWorldConfig.java b/src/main/java/org/spigotmc/SpigotWorldConfig.java
index 93ab1c1..71f772c 100644
--- a/src/main/java/org/spigotmc/SpigotWorldConfig.java
+++ b/src/main/java/org/spigotmc/SpigotWorldConfig.java
@@ -273,4 +273,11 @@ public class SpigotWorldConfig
         maxBulkChunk = getInt( "max-bulk-chunks", 10 );
         log( "Sending up to " + maxBulkChunk + " chunks per packet" );
     }
+
+    public int maxCollisionsPerEntity;
+    private void maxEntityCollision()
+    {
+        maxCollisionsPerEntity = getInt( "max-entity-collisions", 8 );
+        log( "Max Entity Collisions: " + maxCollisionsPerEntity );
+    }
 }
-- 
2.1.0