def get_src_from_action(action):
  """ get_src_from_action returns src ref in action if any
      Args:
        action: proto Action object that might contain a src
  """
  if action.WhichOneof('action') == 'add_file':
    return action.add_file.src
  if action.WhichOneof('action') == 'add_windows_package':
    return action.add_windows_package.src
  if action.WhichOneof('action') == 'add_windows_driver':
    return action.add_windows_driver.src