ResourceMutex.php

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<?php
 
/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
 
namespace ‪TYPO3\CMS\Core\Locking;
 
use ‪TYPO3\CMS\Core\Locking\Exception\LockAcquireException;
use ‪TYPO3\CMS\Core\Locking\Exception\LockAcquireWouldBlockException;
use ‪TYPO3\CMS\Core\Locking\Exception\LockCreateException;
 
class ‪ResourceMutex
{
    private array ‪$accessLocks = [];
 
    private array ‪$workerLocks = [];
 
    public function ‪__construct(private readonly ‪LockFactory $lockFactory) {}
 
    public function ‪acquireLock(string $scope, string $key): bool
    {
        $this->accessLocks[$scope] = $this->lockFactory->createLocker($scope);
        $this->workerLocks[$scope] = $this->lockFactory->createLocker(
            $key,
            ‪LockingStrategyInterface::LOCK_CAPABILITY_EXCLUSIVE | ‪LockingStrategyInterface::LOCK_CAPABILITY_NOBLOCK
        );
        $hadToWaitForLock = false;
        do {
            if (!$this->accessLocks[$scope]->acquire()) {
                throw new \RuntimeException('Could not acquire access lock for "' . $scope . '".', 1601923209);
            }
            try {
                $locked = $this->workerLocks[$scope]->acquire(
                    ‪LockingStrategyInterface::LOCK_CAPABILITY_EXCLUSIVE | ‪LockingStrategyInterface::LOCK_CAPABILITY_NOBLOCK
                );
            } catch (‪LockAcquireWouldBlockException $e) {
                // Somebody else has the lock, we keep waiting.
                // First release the access lock, it will be acquired in next iteration again.
                $this->accessLocks[$scope]->release();
                // Mark "We had to wait".
                $hadToWaitForLock = true;
                // Now lets make a short break (20ms) until we try again, since
                // the page generation by the lock owner will take a while.
                usleep(20000);
                continue;
            }
            $this->accessLocks[$scope]->release();
            if ($locked) {
                break;
            }
            throw new \RuntimeException('Could not acquire process lock for "' . $scope . '" with key "' . $key . '".', 1601923215);
        } while (true);
        return $hadToWaitForLock;
    }
 
    public function ‪releaseLock(string $scope): void
    {
        if ($this->accessLocks[$scope] ?? null) {
            if (!$this->accessLocks[$scope]->acquire()) {
                throw new \RuntimeException('Could not acquire access lock for "' . $scope . '".', 1601923319);
            }
            $this->workerLocks[$scope]->release();
            $this->workerLocks[$scope]->destroy();
            $this->workerLocks[$scope] = null;
            $this->accessLocks[$scope]->release();
            $this->accessLocks[$scope] = null;
        }
    }
}