Function pipe

tools/pseudo-tty.py:16–44

(sfd, dfd)

def pipe(sfd, dfd):
  try:
    data = os.read(sfd, 256)
  except OSError as e:
    if e.errno != errno.EIO:
      raise
    return True  # EOF

  if not data:
    return True  # EOF

  if dfd == STDOUT:
    # Work around platform quirks. Some platforms echo ^D as \x04
    # (AIX, BSDs) and some don't (Linux).
    #
    # The comparison against b' '[0] is because |data| is
    # a string in python2 but a bytes object in python3.
    filt = lambda c: c >= b' '[0] or c in b'\t\n\r\f'
    data = filter(filt, data)
    data = bytes(data)

  while data:
    try:
      n = os.write(dfd, data)
    except OSError as e:
      if e.errno != errno.EIO:
        raise
      return True  # EOF
    data = data[n:]


if __name__ == '__main__':