From 69273f3ff72214c4b6250d292f93b321e3c54358 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Sun, 21 May 2023 16:37:41 +0100
Subject: [PATCH] AsyncTask::setResult(): permit returning ThreadSafe objects
 to the main thread

this is now supported thanks to the object rescue feature implemented in pthreads 5.1, making returning of thread-safe values from async tasks possible.
This needs to be explicitly supported, since otherwise it will attempt to serialize them, which isn't supported anymore.
---
 src/scheduler/AsyncTask.php                   |  6 +-
 tests/phpunit/scheduler/AsyncPoolTest.php     | 19 +++++++
 .../scheduler/ThreadSafeResultAsyncTask.php   | 55 +++++++++++++++++++
 3 files changed, 77 insertions(+), 3 deletions(-)
 create mode 100644 tests/phpunit/scheduler/ThreadSafeResultAsyncTask.php

diff --git a/src/scheduler/AsyncTask.php b/src/scheduler/AsyncTask.php
index c48097bbc..367957b4e 100644
--- a/src/scheduler/AsyncTask.php
+++ b/src/scheduler/AsyncTask.php
@@ -25,6 +25,7 @@ namespace pocketmine\scheduler;
 
 use pmmp\thread\Runnable;
 use pmmp\thread\Thread as NativeThread;
+use pmmp\thread\ThreadSafe;
 use pmmp\thread\ThreadSafeArray;
 use pocketmine\thread\NonThreadSafeValue;
 use function assert;
@@ -70,8 +71,7 @@ abstract class AsyncTask extends Runnable{
 	/** @phpstan-var ThreadSafeArray<int, string> */
 	public ThreadSafeArray $progressUpdates;
 
-	/** @phpstan-var NonThreadSafeValue<mixed>|string|int|bool|float|null */
-	private NonThreadSafeValue|string|int|bool|null|float $result = null;
+	private ThreadSafe|string|int|bool|null|float $result = null;
 	private bool $cancelRun = false;
 	private bool $submitted = false;
 
@@ -124,7 +124,7 @@ abstract class AsyncTask extends Runnable{
 	}
 
 	public function setResult(mixed $result) : void{
-		$this->result = is_scalar($result) || is_null($result) ? $result : new NonThreadSafeValue($result);
+		$this->result = is_scalar($result) || is_null($result) || $result instanceof ThreadSafe ? $result : new NonThreadSafeValue($result);
 	}
 
 	public function cancelRun() : void{
diff --git a/tests/phpunit/scheduler/AsyncPoolTest.php b/tests/phpunit/scheduler/AsyncPoolTest.php
index 9a61c33ff..436251d9e 100644
--- a/tests/phpunit/scheduler/AsyncPoolTest.php
+++ b/tests/phpunit/scheduler/AsyncPoolTest.php
@@ -24,6 +24,8 @@ declare(strict_types=1);
 namespace pocketmine\scheduler;
 
 use PHPUnit\Framework\TestCase;
+use pmmp\thread\ThreadSafeArray;
+use pocketmine\promise\PromiseResolver;
 use pocketmine\snooze\SleeperHandler;
 use pocketmine\utils\MainLogger;
 use function define;
@@ -69,4 +71,21 @@ class AsyncPoolTest extends TestCase{
 		}
 		self::assertTrue(PublishProgressRaceAsyncTask::$success, "Progress was not reported before task completion");
 	}
+
+	public function testThreadSafeSetResult() : void{
+		$resolver = new PromiseResolver();
+		$resolver->getPromise()->onCompletion(
+			function(ThreadSafeArray $result) : void{
+				self::assertCount(1, $result);
+				self::assertSame(["foo"], (array) $result);
+			},
+			function() : void{
+				self::fail("Promise failed");
+			}
+		);
+		$this->pool->submitTask(new ThreadSafeResultAsyncTask($resolver));
+		while($this->pool->collectTasks()){
+			usleep(50 * 1000);
+		}
+	}
 }
diff --git a/tests/phpunit/scheduler/ThreadSafeResultAsyncTask.php b/tests/phpunit/scheduler/ThreadSafeResultAsyncTask.php
new file mode 100644
index 000000000..750c56834
--- /dev/null
+++ b/tests/phpunit/scheduler/ThreadSafeResultAsyncTask.php
@@ -0,0 +1,55 @@
+<?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\scheduler;
+
+use pmmp\thread\ThreadSafe;
+use pmmp\thread\ThreadSafeArray;
+use pocketmine\promise\PromiseResolver;
+
+class ThreadSafeResultAsyncTask extends AsyncTask{
+	private const TLS_KEY_PROMISE = "promise";
+
+	/**
+	 * @phpstan-param PromiseResolver<ThreadSafe> $promise
+	 */
+	public function __construct(
+		PromiseResolver $promise
+	){
+		$this->storeLocal(self::TLS_KEY_PROMISE, $promise);
+	}
+
+	public function onRun() : void{
+		//this only works in pthreads 5.1+ and pmmpthread
+		//in prior versions the ThreadSafe would be destroyed before onCompletion is called
+		$result = new ThreadSafeArray();
+		$result[] = "foo";
+		$this->setResult($result);
+	}
+
+	public function onCompletion() : void{
+		/** @var PromiseResolver<ThreadSafe> $promise */
+		$promise = $this->fetchLocal(self::TLS_KEY_PROMISE);
+		$promise->resolve($this->getResult());
+	}
+}