PocketMine-MP/src/scheduler/AsyncTask.php

262 lines
8.2 KiB
PHP

<?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 pocketmine\utils\AssumptionFailedError;
use function igbinary_serialize;
use function igbinary_unserialize;
use function is_scalar;
use function is_string;
use function spl_object_id;
/**
* Class used to run async tasks in other threads.
*
* An AsyncTask does not have its own thread. It is queued into an AsyncPool and executed if there is an async worker
* with no AsyncTask running. Therefore, an AsyncTask SHOULD NOT execute for more than a few seconds. For tasks that
* run for a long time or infinitely, start another thread instead.
*
* WARNING: Any non-Threaded objects WILL BE SERIALIZED when assigned to members of AsyncTasks or other Threaded object.
* If later accessed from said Threaded object, you will be operating on a COPY OF THE OBJECT, NOT THE ORIGINAL OBJECT.
* If you want to store non-serializable objects to access when the task completes, store them using
* {@link AsyncTask::storeLocal}.
*
* WARNING: As of pthreads v3.1.6, arrays are converted to Volatile objects when assigned as members of Threaded objects.
* Keep this in mind when using arrays stored as members of your AsyncTask.
*
* WARNING: Do not call PocketMine-MP API methods from other Threads!!
*/
abstract class AsyncTask extends \Threaded{
/**
* @var \ArrayObject|mixed[]|null object hash => mixed data
* @phpstan-var \ArrayObject<int, array<string, mixed>>|null
*
* Used to store objects which are only needed on one thread and should not be serialized.
*/
private static $threadLocalStorage = null;
/** @var AsyncWorker|null $worker */
public $worker = null;
/** @var \Threaded */
public $progressUpdates;
/** @var scalar|null */
private $result = null;
/** @var bool */
private $serialized = false;
/** @var bool */
private $cancelRun = false;
/** @var bool */
private $submitted = false;
/** @var bool */
private $crashed = false;
/** @var bool */
private $finished = false;
public function run() : void{
$this->result = null;
if(!$this->cancelRun){
try{
$this->onRun();
}catch(\Throwable $e){
$this->crashed = true;
$this->worker->handleException($e);
}
}
$this->finished = true;
}
public function isCrashed() : bool{
return $this->crashed or $this->isTerminated();
}
/**
* Returns whether this task has finished executing, whether successfully or not. This differs from isRunning()
* because it is not true prior to task execution.
*/
public function isFinished() : bool{
return $this->finished or $this->isCrashed();
}
/**
* @return mixed
*/
public function getResult(){
if($this->serialized){
if(!is_string($this->result)) throw new AssumptionFailedError("Result expected to be a serialized string");
return igbinary_unserialize($this->result);
}
return $this->result;
}
public function cancelRun() : void{
$this->cancelRun = true;
}
public function hasCancelledRun() : bool{
return $this->cancelRun;
}
public function hasResult() : bool{
return $this->result !== null;
}
/**
* @param mixed $result
*/
public function setResult($result) : void{
$this->result = ($this->serialized = !is_scalar($result)) ? igbinary_serialize($result) : $result;
}
public function setSubmitted() : void{
$this->submitted = true;
}
public function isSubmitted() : bool{
return $this->submitted;
}
/**
* Actions to execute when run
*/
abstract public function onRun() : void;
/**
* Actions to execute when completed (on main thread)
* Implement this if you want to handle the data in your AsyncTask after it has been processed
*/
public function onCompletion() : void{
}
/**
* Call this method from {@link AsyncTask::onRun} (AsyncTask execution thread) to schedule a call to
* {@link AsyncTask::onProgressUpdate} from the main thread with the given progress parameter.
*
* @param mixed $progress A value that can be safely serialize()'ed.
*/
public function publishProgress($progress) : void{
$this->progressUpdates[] = igbinary_serialize($progress);
}
/**
* @internal Only call from AsyncPool.php on the main thread
*/
public function checkProgressUpdates() : void{
while($this->progressUpdates->count() !== 0){
$progress = $this->progressUpdates->shift();
$this->onProgressUpdate(igbinary_unserialize($progress));
}
}
/**
* Called from the main thread after {@link AsyncTask::publishProgress} is called.
* All {@link AsyncTask::publishProgress} calls should result in {@link AsyncTask::onProgressUpdate} calls before
* {@link AsyncTask::onCompletion} is called.
*
* @param mixed $progress The parameter passed to {@link AsyncTask#publishProgress}. It is serialize()'ed
* and then unserialize()'ed, as if it has been cloned.
*/
public function onProgressUpdate($progress) : void{
}
/**
* Called from the main thread when the async task experiences an error during onRun(). Use this for things like
* promise rejection.
*/
public function onError() : void{
}
/**
* Saves mixed data in thread-local storage. Data stored using this storage is **only accessible from the thread it
* was stored on**. Data stored using this method will **not** be serialized.
* This can be used to store references to variables which you need later on on the same thread, but not others.
*
* For example, plugin references could be stored in the constructor of the async task (which is called on the main
* thread) using this, and then fetched in onCompletion() (which is also called on the main thread), without them
* becoming serialized.
*
* Scalar types can be stored directly in class properties instead of using this storage.
*
* Objects stored in this storage can be retrieved using fetchLocal() on the same thread that this method was called
* from.
*
* @param mixed $complexData the data to store
*/
protected function storeLocal(string $key, $complexData) : void{
if(self::$threadLocalStorage === null){
/*
* It's necessary to use an object (not array) here because pthreads is stupid. Non-default array statics
* will be inherited when task classes are copied to the worker thread, which would cause unwanted
* inheritance of primitive thread-locals, which we really don't want for various reasons.
* It won't try to inherit objects though, so this is the easiest solution.
*/
self::$threadLocalStorage = new \ArrayObject();
}
self::$threadLocalStorage[spl_object_id($this)][$key] = $complexData;
}
/**
* Retrieves data stored in thread-local storage.
*
* If you used storeLocal(), you can use this on the same thread to fetch data stored. This should be used during
* onProgressUpdate() and onCompletion() to fetch thread-local data stored on the parent thread.
*
* @return mixed
*
* @throws \InvalidArgumentException if no data were stored by this AsyncTask instance.
*/
protected function fetchLocal(string $key){
$id = spl_object_id($this);
if(self::$threadLocalStorage === null or !isset(self::$threadLocalStorage[$id][$key])){
throw new \InvalidArgumentException("No matching thread-local data found on this thread");
}
return self::$threadLocalStorage[$id][$key];
}
final public function __destruct(){
$this->reallyDestruct();
if(self::$threadLocalStorage !== null and isset(self::$threadLocalStorage[$h = spl_object_id($this)])){
unset(self::$threadLocalStorage[$h]);
if(self::$threadLocalStorage->count() === 0){
self::$threadLocalStorage = null;
}
}
}
/**
* Override this to do normal __destruct() cleanup from a child class.
*/
protected function reallyDestruct() : void{
}
}