From ee7d4728d8c813af39cab5b03736cc6df76f2a2b Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Mon, 19 Dec 2022 21:20:21 +0000
Subject: [PATCH] World: added cache for isChunkTickable() this considerably
 reduces the amount of work done by the function, since it's usually checking
 the same chunks over and over again.

---
 src/world/World.php | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/world/World.php b/src/world/World.php
index b20960755..8c14c7fc1 100644
--- a/src/world/World.php
+++ b/src/world/World.php
@@ -1151,6 +1151,8 @@ class World implements ChunkManager{
 		/** @var bool[] $chunkTickList chunkhash => dummy */
 		$chunkTickList = [];
 
+		$chunkTickableCache = [];
+
 		$centerChunks = [];
 
 		$selector = new ChunkSelector();
@@ -1170,7 +1172,7 @@ class World implements ChunkManager{
 				$centerChunkZ
 			) as $hash){
 				World::getXZ($hash, $chunkX, $chunkZ);
-				if(!isset($chunkTickList[$hash]) && isset($this->chunks[$hash]) && $this->isChunkTickable($chunkX, $chunkZ)){
+				if(!isset($chunkTickList[$hash]) && isset($this->chunks[$hash]) && $this->isChunkTickable($chunkX, $chunkZ, $chunkTickableCache)){
 					$chunkTickList[$hash] = true;
 				}
 			}
@@ -1185,14 +1187,29 @@ class World implements ChunkManager{
 		}
 	}
 
-	private function isChunkTickable(int $chunkX, int $chunkZ) : bool{
+	/**
+	 * @param bool[] &$cache
+	 *
+	 * @phpstan-param array<int, bool> $cache
+	 * @phpstan-param-out array<int, bool> $cache
+	 */
+	private function isChunkTickable(int $chunkX, int $chunkZ, array &$cache) : bool{
 		for($cx = -1; $cx <= 1; ++$cx){
 			for($cz = -1; $cz <= 1; ++$cz){
+				$chunkHash = World::chunkHash($chunkX + $cx, $chunkZ + $cz);
+				if(isset($cache[$chunkHash])){
+					if(!$cache[$chunkHash]){
+						return false;
+					}
+					continue;
+				}
 				if($this->isChunkLocked($chunkX + $cx, $chunkZ + $cz)){
+					$cache[$chunkHash] = false;
 					return false;
 				}
 				$adjacentChunk = $this->getChunk($chunkX + $cx, $chunkZ + $cz);
 				if($adjacentChunk === null || !$adjacentChunk->isPopulated()){
+					$cache[$chunkHash] = false;
 					return false;
 				}
 				$lightPopulatedState = $adjacentChunk->isLightPopulated();
@@ -1200,8 +1217,11 @@ class World implements ChunkManager{
 					if($lightPopulatedState === false){
 						$this->orderLightPopulation($chunkX + $cx, $chunkZ + $cz);
 					}
+					$cache[$chunkHash] = false;
 					return false;
 				}
+
+				$cache[$chunkHash] = true;
 			}
 		}