generation: drop AsyncWorker thread-local storage in favour of a more specialized storage

src/world/generator/GeneratorRegisterTask.php

@@ -60,13 +60,11 @@ class GeneratorRegisterTask extends AsyncTask{
 
 	public function onRun() : void{
 		$manager = new SimpleChunkManager($this->worldHeight);
-		$this->worker->saveToThreadStore("generation.world{$this->worldId}.manager", $manager);
-
 		/**
 		 * @var Generator $generator
 		 * @see Generator::__construct()
 		 */
 		$generator = new $this->generatorClass($this->seed, igbinary_unserialize($this->settings));
-		$this->worker->saveToThreadStore("generation.world{$this->worldId}.generator", $generator);
+		ThreadLocalGeneratorContext::register(new ThreadLocalGeneratorContext($generator, $manager), $this->worldId);
 	}
 }

src/world/generator/GeneratorUnregisterTask.php

@@ -36,7 +36,6 @@ class GeneratorUnregisterTask extends AsyncTask{
 	}
 
 	public function onRun() : void{
-		$this->worker->removeFromThreadStore("generation.world{$this->worldId}.manager");
-		$this->worker->removeFromThreadStore("generation.world{$this->worldId}.generator");
+		ThreadLocalGeneratorContext::unregister($this->worldId);
 	}
 }

src/world/generator/PopulationTask.php

@@ -72,12 +72,13 @@ class PopulationTask extends AsyncTask{
 	}
 
 	public function onRun() : void{
-		$manager = $this->worker->getFromThreadStore("generation.world{$this->worldId}.manager");
-		$generator = $this->worker->getFromThreadStore("generation.world{$this->worldId}.generator");
-		if(!($manager instanceof SimpleChunkManager) or !($generator instanceof Generator)){
+		$context = ThreadLocalGeneratorContext::fetch($this->worldId);
+		if($context === null){
 			$this->state = false;
 			return;
 		}
+		$generator = $context->getGenerator();
+		$manager = $context->getChunkManager();
 
 		/** @var Chunk[] $chunks */
 		$chunks = [];

src/world/generator/ThreadLocalGeneratorContext.php

@@ -0,0 +1,63 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\world\generator;
+
+use pocketmine\world\SimpleChunkManager;
+
+/**
+ * Manages thread-local caches for generators and the things needed to support them
+ */
+final class ThreadLocalGeneratorContext{
+	/**
+	 * @var self[]
+	 * @phpstan-var array<int, self>
+	 */
+	private static $contexts = [];
+
+	public static function register(self $context, int $worldId) : void{
+		self::$contexts[$worldId] = $context;
+	}
+
+	public static function unregister(int $worldId) : void{
+		unset(self::$contexts[$worldId]);
+	}
+
+	public static function fetch(int $worldId) : ?self{
+		return self::$contexts[$worldId] ?? null;
+	}
+
+	/** @var Generator */
+	private $generator;
+	/** @var SimpleChunkManager */
+	private $chunkManager;
+
+	public function __construct(Generator $generator, SimpleChunkManager $chunkManager){
+		$this->generator = $generator;
+		$this->chunkManager = $chunkManager;
+	}
+
+	public function getGenerator() : Generator{ return $this->generator; }
+
+	public function getChunkManager() : SimpleChunkManager{ return $this->chunkManager; }
+}