code: protected function closeFile(SplFileObject &$file)
      {
          if (!$this->getConfig()->useGzip() && !$file->flock(LOCK_UN)) {
              $file = null;
              throw new Exception('Could not unlock file');
          }
  
          $file = null;
      }
docs: Close the database file.
  
  @param SplFileObject $file
  
  @throws Exception