ParallelExecutor.php

<?php
declare( strict_types = 1 );
 
namespace MediaWiki\Extension\Translate\Utilities;
 
use MediaWiki\MediaWikiServices;
 
class ParallelExecutor {
    private $pids = [];
 
    public function __construct(
        private readonly int $threads = 1,
    ) {
    }
 
    public function runInParallel( callable $mainThread, callable $forkThread ): void {
        // Fork to increase speed with parallelism. Also helps with memory usage if there are leaks.
        $pid = -1;
        if ( function_exists( 'pcntl_fork' ) ) {
            $pid = pcntl_fork();
        }
 
        if ( $pid === 0 ) {
            MediaWikiServices::resetChildProcessServices();
            $forkThread();
            exit();
        } elseif ( $pid === -1 ) {
            // Fork failed do it serialized
            $forkThread();
        } else {
            // Main thread
            $mainThread( $pid );
            $this->pids[$pid] = true;
 
            // If we hit the thread limit, wait for any child to finish.
            if ( count( $this->pids ) >= $this->threads ) {
                $status = 0;
                $pid = pcntl_wait( $status );
                unset( $this->pids[$pid] );
            }
        }
    }
}