class Lock{    const PREFIX_KEY = "MY_LOCK:";    static private $LOCKED = [];        static public function tryLock($key, $expire = 300)    {                $lock = self::PREFIX_KEY.$key;                //已取得到lock(防止同行程重覆要求造成deadlock)        if(self::$LOCKED[$lock]) {            ++self::$LOCKED[$lock];            return true;        }                //處理lock        $redis = &AppBase::getRedis();        if(!$redis->setnx($lock, '')) {            return false;        }        $redis->expire($lock, $expire); //防止crash沒解鎖                //成功lock        ++self::$LOCKED[$lock];        return true;    }        static public function unlock($key)    {                $lock = self::PREFIX_KEY.$key;                if(--self::$LOCKED[$lock] <= 0) {            AppBase::getRedis()->delete($lock);            unset(self::$LOCKED[$lock]);        }            }        static public function blockLock($key, $max_try = 60, $sleep = 1, $expire = 300)    {        $t = 0;        while(++$t <= $max_try) {            if(self::tryLock($key, $expire)) {                return true;            }            usleep(intval($sleep * 1000000));        }        return false;    }    }