bulkloader.py 文件源码

def CheckOutputFile(filename):
  """Check that the given file does not exist and can be opened for writing.

  Args:
    filename: The name of the file.

  Raises:
    FileExistsError: if the given filename is not found
    FileNotWritableError: if the given filename is not readable.
    """
  full_path = os.path.abspath(filename)
  if os.path.exists(full_path):
    raise FileExistsError('%s: output file exists' % filename)
  elif not os.access(os.path.dirname(full_path), os.W_OK):
    raise FileNotWritableError(
        '%s: not writable' % os.path.dirname(full_path))