def _GetParallelUploadTrackerFileLinesForComponents(components):
  """Return a list of the lines for use in a parallel upload tracker file.

  The lines represent the given components, using the format as described in
  _CreateParallelUploadTrackerFile.

  Args:
    components: A list of ObjectFromTracker objects that were uploaded.

  Returns:
    Lines describing components with their generation for outputting to the
    tracker file.
  """
  lines = []
  for component in components:
    generation = None
    generation = component.generation
    if not generation:
      generation = ''
    lines += [component.object_name, str(generation)]
  return lines