Dylan K. Taylor b331f8e1c9 AsyncWorker: added removeFromThreadStore()
and use it instead of overwriting with null things, which still occupies memory
2018-06-07 10:12:50 +01:00

327 lines
11 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\Collectable;
use pocketmine\Server;
/**
* 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 {@link \pocketmine\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 Collectable{
/**
* @var \SplObjectStorage|null
* Used to store objects on the main thread which should not be serialized.
*/
private static $localObjectStorage;
/** @var AsyncWorker $worker */
public $worker = null;
/** @var \Threaded */
public $progressUpdates;
private $result = null;
private $serialized = false;
private $cancelRun = false;
/** @var int|null */
private $taskId = null;
private $crashed = false;
public function run(){
$this->result = null;
if(!$this->cancelRun){
try{
$this->onRun();
}catch(\Throwable $e){
$this->crashed = true;
$this->worker->handleException($e);
}
}
$this->setGarbage();
}
public function isCrashed() : bool{
return $this->crashed;
}
/**
* @return mixed
*/
public function getResult(){
return $this->serialized ? unserialize($this->result) : $this->result;
}
public function cancelRun(){
$this->cancelRun = true;
}
public function hasCancelledRun() : bool{
return $this->cancelRun;
}
/**
* @return bool
*/
public function hasResult() : bool{
return $this->result !== null;
}
/**
* @param mixed $result
* @param bool $serialize
*/
public function setResult($result, bool $serialize = true){
$this->result = $serialize ? serialize($result) : $result;
$this->serialized = $serialize;
}
public function setTaskId(int $taskId){
$this->taskId = $taskId;
}
/**
* @return int|null
*/
public function getTaskId(){
return $this->taskId;
}
/**
* @see AsyncWorker::getFromThreadStore()
*
* @param string $identifier
* @return mixed
*/
public function getFromThreadStore(string $identifier){
if($this->worker === null or $this->isGarbage()){
throw new \BadMethodCallException("Objects stored in AsyncWorker thread-local storage can only be retrieved during task execution");
}
return $this->worker->getFromThreadStore($identifier);
}
/**
* @see AsyncWorker::saveToThreadStore()
*
* @param string $identifier
* @param mixed $value
*/
public function saveToThreadStore(string $identifier, $value){
if($this->worker === null or $this->isGarbage()){
throw new \BadMethodCallException("Objects can only be added to AsyncWorker thread-local storage during task execution");
}
$this->worker->saveToThreadStore($identifier, $value);
}
/**
* @see AsyncWorker::removeFromThreadStore()
*
* @param string $identifier
*/
public function removeFromThreadStore(string $identifier) : void{
if($this->worker === null or $this->isGarbage()){
throw new \BadMethodCallException("Objects can only be removed from AsyncWorker thread-local storage during task execution");
}
$this->worker->removeFromThreadStore($identifier);
}
/**
* Actions to execute when run
*
* @return void
*/
abstract public function onRun();
/**
* 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
*
* @param Server $server
*
* @return void
*/
public function onCompletion(Server $server){
}
/**
* 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){
$this->progressUpdates[] = serialize($progress);
}
/**
* @internal Only call from AsyncPool.php on the main thread
*
* @param Server $server
*/
public function checkProgressUpdates(Server $server){
while($this->progressUpdates->count() !== 0){
$progress = $this->progressUpdates->shift();
$this->onProgressUpdate($server, 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 Server $server
* @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(Server $server, $progress){
}
/**
* Saves mixed data in thread-local storage on the parent thread. You may use this to retain references to objects
* or arrays which you need to access in {@link AsyncTask#onCompletion} which cannot be stored as a property of
* your task (due to them becoming serialized).
*
* Scalar types can be stored directly in class properties instead of using this storage.
*
* Objects stored in this storage MUST be retrieved through {@link #fetchLocal} when {@link #onCompletion} is called.
* Otherwise, a NOTICE level message will be raised and the reference will be removed after onCompletion exits.
*
* WARNING: Use this method carefully. It might take a long time before an AsyncTask is completed. PocketMine will
* keep a strong reference to objects passed in this method. This may result in a light memory leak. Usually this
* does not cause memory failure, but be aware that the object may be no longer usable when the AsyncTask completes.
* (E.g. a {@link \pocketmine\Level} object is no longer usable because it is unloaded while the AsyncTask is
* executing, or even a plugin might be unloaded). Since PocketMine keeps a strong reference, the objects are still
* valid, but the implementation is responsible for checking whether these objects are still usable.
*
* WARNING: THIS METHOD SHOULD ONLY BE CALLED FROM THE MAIN THREAD!
*
* @param mixed $complexData the data to store
*
* @throws \BadMethodCallException if called from any thread except the main thread
*/
protected function storeLocal($complexData){
if($this->worker !== null and $this->worker === \Thread::getCurrentThread()){
throw new \BadMethodCallException("Objects can only be stored from the parent thread");
}
if(self::$localObjectStorage === null){
self::$localObjectStorage = new \SplObjectStorage(); //lazy init
}
if(isset(self::$localObjectStorage[$this])){
throw new \InvalidStateException("Already storing complex data for this async task");
}
self::$localObjectStorage[$this] = $complexData;
}
/**
* Returns and removes mixed data in thread-local storage on the parent thread. Call this method from
* {@link AsyncTask#onCompletion} to fetch the data stored in the object store, if any.
*
* If no data was stored in the local store, or if the data was already retrieved by a previous call to fetchLocal,
* do NOT call this method, or an exception will be thrown.
*
* Do not call this method from {@link AsyncTask#onProgressUpdate}, because this method deletes stored data, which
* means that you will not be able to retrieve it again afterwards. Use {@link AsyncTask#peekLocal} instead to
* retrieve stored data without removing it from the store.
*
* WARNING: THIS METHOD SHOULD ONLY BE CALLED FROM THE MAIN THREAD!
*
* @return mixed
*
* @throws \RuntimeException if no data were stored by this AsyncTask instance.
* @throws \BadMethodCallException if called from any thread except the main thread
*/
protected function fetchLocal(){
try{
return $this->peekLocal();
}finally{
if(self::$localObjectStorage !== null){
unset(self::$localObjectStorage[$this]);
}
}
}
/**
* Returns mixed data in thread-local storage on the parent thread **without clearing** it. Call this method from
* {@link AsyncTask#onProgressUpdate} to fetch the data stored if you need to be able to access the data later on,
* such as in another progress update.
*
* Use {@link AsyncTask#fetchLocal} instead from {@link AsyncTask#onCompletion}, because this method does not delete
* the data, and not clearing the data will result in a warning for memory leak after {@link AsyncTask#onCompletion}
* finished executing.
*
* WARNING: THIS METHOD SHOULD ONLY BE CALLED FROM THE MAIN THREAD!
*
* @return mixed
*
* @throws \RuntimeException if no data were stored by this AsyncTask instance
* @throws \BadMethodCallException if called from any thread except the main thread
*/
protected function peekLocal(){
if($this->worker !== null and $this->worker === \Thread::getCurrentThread()){
throw new \BadMethodCallException("Objects can only be retrieved from the parent thread");
}
if(self::$localObjectStorage === null or !isset(self::$localObjectStorage[$this])){
throw new \InvalidStateException("No complex data stored for this async task");
}
return self::$localObjectStorage[$this];
}
/**
* @internal Called by the AsyncPool to destroy any leftover stored objects that this task failed to retrieve.
* @return bool
*/
public function removeDanglingStoredObjects() : bool{
if(self::$localObjectStorage !== null and isset(self::$localObjectStorage[$this])){
unset(self::$localObjectStorage[$this]);
return true;
}
return false;
}
}