win32_file_watcher.py 文件源码

def _monitor(self):
    buff = ctypes.create_string_buffer(_BUFF_SIZE)
    while not self._stop.isSet():
      size_returned = ctypes.c_ulong(0)
      result = ctypes.windll.kernel32.ReadDirectoryChangesW(
          self._directory_handle,
          buff,
          ctypes.c_ulong(_BUFF_SIZE),
          True,  # recursive.
          ctypes.c_ulong(_FILE_NOTIFY_CHANGE_ANY),
          ctypes.byref(size_returned),
          None,
          None)  # this is a blocking call.
      if result == 0 and ctypes.GetLastError() == _ERROR_NOTIFY_ENUM_DIR:
        logging.warning('Buffer overflow while monitoring for file changes.')
        # we need to notify that something changed anyway
        with self._lock:
          self._change_set |= {'Unknown file'}
      if result != 0 and size_returned.value != 0:
        additional_changes = _parse_buffer(buff)
        with self._lock:
          self._change_set |= additional_changes
          self._change_event.set()