git_common.py 文件源码

def less():  # pragma: no cover
  """Runs 'less' as context manager yielding its stdin as a PIPE.

  Automatically checks if sys.stdout is a non-TTY stream. If so, it avoids
  running less and just yields sys.stdout.
  """
  if not setup_color.IS_TTY:
    yield sys.stdout
    return

  # Run with the same options that git uses (see setup_pager in git repo).
  # -F: Automatically quit if the output is less than one screen.
  # -R: Don't escape ANSI color codes.
  # -X: Don't clear the screen before starting.
  cmd = ('less', '-FRX')
  try:
    proc = subprocess2.Popen(cmd, stdin=subprocess2.PIPE)
    yield proc.stdin
  finally:
    proc.stdin.close()
    proc.wait()