server/lib/public/files/storage/ilockingstorage.php

<?php
/**
 * @author Robin Appelman <icewind@owncloud.com>
 *
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

namespace OCP\Files\Storage;

use OCP\Lock\ILockingProvider;

/**
 * Storage backends that require explicit locking
 *
 * Storage backends implementing this interface do not need to implement their own locking implementation but should use the provided lockingprovider instead
 * The implementation of the locking methods only need to map internal storage paths to "lock keys"
 *
 * @since 9.0.0
 */
interface ILockingStorage {
	/**
	 * @param string $path The path of the file to acquire the lock for
	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
	 * @param \OCP\Lock\ILockingProvider $provider
	 * @throws \OCP\Lock\LockedException
	 * @since 9.0.0
	 */
	public function acquireLock($path, $type, ILockingProvider $provider);

	/**
	 * @param string $path The path of the file to acquire the lock for
	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
	 * @param \OCP\Lock\ILockingProvider $provider
	 * @since 9.0.0
	 */
	public function releaseLock($path, $type, ILockingProvider $provider);

	/**
	 * @param string $path The path of the file to change the lock for
	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
	 * @param \OCP\Lock\ILockingProvider $provider
	 * @throws \OCP\Lock\LockedException
	 * @since 9.0.0
	 */
	public function changeLock($path, $type, ILockingProvider $provider);
}