Code Coverage for /workspace/src/extensions/Translate/src/Utilities/ParallelExecutor.php

1	<?php
2	declare( strict_types = 1 );
3
4	namespace MediaWiki\Extension\Translate\Utilities;
5
6	use MediaWiki\MediaWikiServices;
7
8	/**
9	* Helper class for maintenance scripts to run things in parallel.
10	*
11	* See also ForkContoller and https://phabricator.wikimedia.org/T201970.
12	*
13	* @since 2020.11
14	* @license GPL-2.0-or-later
15	* @author Niklas Laxström
16	*/
17	class ParallelExecutor {
18	/** @var true[] */
19	private $pids = [];
20	/** @var int */
21	private $threads;
22
23	public function __construct( int $threads = 1 ) {
24	$this->threads = $threads;
25	}
26
27	public function runInParallel( callable $mainThread, callable $forkThread ): void {
28	// Fork to increase speed with parallelism. Also helps with memory usage if there are leaks.
29	$pid = -1;
30	if ( function_exists( 'pcntl_fork' ) ) {
31	$pid = pcntl_fork();
32	}
33
34	if ( $pid === 0 ) {
35	MediaWikiServices::resetChildProcessServices();
36	$forkThread();
37	exit();
38	} elseif ( $pid === -1 ) {
39	// Fork failed do it serialized
40	$forkThread();
41	} else {
42	// Main thread
43	$mainThread( $pid );
44	$this->pids[$pid] = true;
45
46	// If we hit the thread limit, wait for any child to finish.
47	if ( count( $this->pids ) >= $this->threads ) {
48	$status = 0;
49	$pid = pcntl_wait( $status );
50	unset( $this->pids[$pid] );
51	}
52	}
53	}
54	}