file_cache.py 文件源码

def __init__(self, max_age):
      """Constructor.

      Args:
        max_age: Cache expiration in seconds.
      """
      self._max_age = max_age
      self._file = os.path.join(tempfile.gettempdir(), FILENAME)
      f = LockedFile(self._file, 'a+', 'r')
      try:
        f.open_and_lock()
        if f.is_locked():
          _read_or_initialize_cache(f)
        # If we can not obtain the lock, other process or thread must
        # have initialized the file.
      except Exception as e:
        LOGGER.warning(e, exc_info=True)
      finally:
        f.unlock_and_close()