src/python/inputimeout/inputimeout.py

   1 import sys
   2
   3 DEFAULT_TIMEOUT = 30.0
   4 INTERVAL = 0.05
   5
   6 SP = ' '
   7 CR = '\r'
   8 LF = '\n'
   9 CRLF = CR + LF
  10
  11
  12 class TimeoutOccurred(Exception):
  13     pass
  14
  15
  16 def echo(string):
  17     sys.stdout.write(string)
  18     sys.stdout.flush()
  19
  20
  21 def posix_inputimeout(prompt='', timeout=DEFAULT_TIMEOUT):
  22     echo(prompt)
  23     sel = selectors.DefaultSelector()
  24     sel.register(sys.stdin, selectors.EVENT_READ)
  25     events = sel.select(timeout)
  26
  27     if events:
  28         key, _ = events[0]
  29         return key.fileobj.readline().rstrip(LF)
  30     else:
  31         echo(LF)
  32         termios.tcflush(sys.stdin, termios.TCIFLUSH)
  33         raise TimeoutOccurred
  34
  35
  36 def win_inputimeout(prompt='', timeout=DEFAULT_TIMEOUT):
  37     echo(prompt)
  38     begin = time.monotonic()
  39     end = begin + timeout
  40     line = ''
  41
  42     while time.monotonic() < end:
  43         if msvcrt.kbhit():
  44             c = msvcrt.getwche()
  45             if c in (CR, LF):
  46                 echo(CRLF)
  47                 return line
  48             if c == '\003':
  49                 raise KeyboardInterrupt
  50             if c == '\b':
  51                 line = line[:-1]
  52                 cover = SP * len(prompt + line + SP)
  53                 echo(''.join([CR, cover, CR, prompt, line]))
  54             else:
  55                 line += c
  56         time.sleep(INTERVAL)
  57
  58     echo(CRLF)
  59     raise TimeoutOccurred
  60
  61
  62 try:
  63     import msvcrt
  64
  65 except ImportError:
  66     import selectors
  67     import termios
  68
  69     inputimeout = posix_inputimeout
  70
  71 else:
  72     import time
  73
  74     inputimeout = win_inputimeout