<?

    /**
    *   Quick and Dirty File Mutex
    *
    *   Copyright(c)2013 SwingNote LLC. All Rights Reserved.
    *
    *   Terms: You may freely use this source code in both
    *   commercial and non-commercial applications, provided
    *   all copyright notices remain intact.
    *
    *   Author:     Markus Diersbock <markus@swingnote.com>
    */
    function mutex($action) {
        $mutex = "lock.mutex";

		try {
			switch ($action) {
				case "check":
					return file_exists($mutex);

				case "create":
					return mutex("check") ? false : touch($mutex);

				case "delete":
					return mutex("check") ? unlink($mutex) : false;

				default:
					return false;
			}
		} catch (Exception $e) {
			return false;
		}

    }

?>