lock.php

<?php
/**
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library 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 along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace OC\Files;

use OCP\Config;
use OC\Files\Filesystem;
use OCP\Files\LockNotAcquiredException;

/**
 * Class Lock
 * @package OC\Files
 */
class Lock implements \OCP\Files\Lock {

	/** @var int $retries Number of lock retries to attempt */
	public static $retries = 40;

	/** @var int $retryInterval Milliseconds between retries */
	public static $retryInterval = 50;

	/** @var string $path Filename of the file as represented in storage */
	protected $path;

	/** @var array $stack A stack of lock data */
	protected $stack = array();

	/** @var resource $handle A file handle used to maintain a lock  */
	protected $handle;

	/** @var string $lockFile Filename of the lock file */
	protected $lockFile;

	/** @var resource $lockFileHandle The file handle used to maintain a lock on the lock file */
	protected $lockFileHandle;

	/**
	 * Constructor for the lock instance
	 * @param string $path Absolute pathname for a local file on which to obtain a lock
	 */
	public function __construct($path) {
		$this->path = Filesystem::normalizePath($path);
	}

	protected function obtainReadLock($existingHandle = null) {
		\OC_Log::write('lock', sprintf('INFO: Read lock requested for %s', $this->path), \OC_Log::DEBUG);
		$timeout = Lock::$retries;

		// Re-use an existing handle or get a new one
		if(empty($existingHandle)) {
			$handle = fopen($this->path, 'r');
		}
		else {
			$handle = $existingHandle;
		}