From c6cd94e6eaec67e31528ad1c871a473e9415bc61 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 18 Jan 2016 00:18:43 -0500
Subject: [PATCH] Optimize Pathfinding

Prevents pathfinding from spamming failures for things such as
arrow attacks.

Also remove a duplicate .getType() call and fix .getType() on others
to make them use the chunk cache vs chunk lookups

diff --git a/src/main/java/net/minecraft/server/NavigationAbstract.java b/src/main/java/net/minecraft/server/NavigationAbstract.java
index d5eaa24..8ebe584 100644
--- a/src/main/java/net/minecraft/server/NavigationAbstract.java
+++ b/src/main/java/net/minecraft/server/NavigationAbstract.java
@@ -82,10 +82,25 @@ public abstract class NavigationAbstract {
     }
 
     public boolean a(Entity entity, double d0) {
+        // PaperSpigot start - Pathfinding optimizations
+        if (this.pathfindFailures > 10 && this.d == null && MinecraftServer.currentTick < this.lastFailure + 40) {
+            return false;
+        }
         PathEntity pathentity = this.a(entity);
 
-        return pathentity != null ? this.a(pathentity, d0) : false;
+        if (pathentity != null && this.a(pathentity, d0)) {
+            this.lastFailure = 0;
+            this.pathfindFailures = 0;
+            return true;
+        } else {
+            this.pathfindFailures++;
+            this.lastFailure = MinecraftServer.currentTick;
+            return false;
+        }
     }
+    private int lastFailure = 0;
+    private int pathfindFailures = 0;
+    // PaperSpigot end
 
     public boolean a(PathEntity pathentity, double d0) {
         if (pathentity == null) {
@@ -205,6 +220,7 @@ public abstract class NavigationAbstract {
     }
 
     public void n() {
+        this.pathfindFailures = 0; this.lastFailure = 0; // PaperSpigot - Pathfinding optimizations
         this.d = null;
     }
 
diff --git a/src/main/java/net/minecraft/server/PathfinderNormal.java b/src/main/java/net/minecraft/server/PathfinderNormal.java
index 0a14c9d..629aa16 100644
--- a/src/main/java/net/minecraft/server/PathfinderNormal.java
+++ b/src/main/java/net/minecraft/server/PathfinderNormal.java
@@ -158,8 +158,8 @@ public class PathfinderNormal extends PathfinderAbstract {
                             flag3 = true;
                         }
 
-                        if (entity.world.getType(blockposition_mutableblockposition).getBlock() instanceof BlockMinecartTrackAbstract) {
-                            if (!(entity.world.getType(blockposition).getBlock() instanceof BlockMinecartTrackAbstract) && !(entity.world.getType(blockposition.down()).getBlock() instanceof BlockMinecartTrackAbstract)) {
+                        if (block instanceof BlockMinecartTrackAbstract) { // PaperSpigot - Pathfinder optimizations
+                            if (!(iblockaccess.getType(blockposition).getBlock() instanceof BlockMinecartTrackAbstract) && !(iblockaccess.getType(blockposition.down()).getBlock() instanceof BlockMinecartTrackAbstract)) { // PaperSpigot - Pathfinder optimizations
                                 return -3;
                             }
                         } else if (!block.b(iblockaccess, blockposition_mutableblockposition) && (!flag1 || !(block instanceof BlockDoor) || block.getMaterial() != Material.WOOD)) {
-- 
2.7.1