Source Code for Module coro.optional

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20   
21  # $Header: //prod/main/ap/shrapnel/coro/optional.py#3 $ 
22   
23  """Functions that can run in or out of coro. 
24   
25  This module provides emulation for some functions to run whether or not the 
26  coro event loop is running. 
27  """ 
28   
29  __version__ = '$Revision: #3 $' 
30   
31  import coro 
32  import signal 
33  import time 
34   
35 -class _shutdown_sigalrm_exc (Exception): 
36      pass 
37   
38 -def _shutdown_sigalrm_handler(unused_signum, unused_frame): 
39      raise _shutdown_sigalrm_exc 
40   
41 -def with_timeout(timeout, function, *args, **kwargs): 
42      """Call a function with a timeout. 
43   
44      This version supports running even if the coro event loop isn't running by 
45      using SIGALRM. 
46   
47      See `coro._coro.sched.with_timeout` for more detail. 
48   
49      :Parameters: 
50          - `timeout`: The number of seconds to wait before raising the timeout. 
51            May be a floating point number. 
52          - `function`: The function to call. 
53   
54      :Return: 
55          Returns the return value of the function. 
56   
57      :Exceptions: 
58          - `coro.TimeoutError`: The timeout expired. 
59      """ 
60      if coro.coro_is_running(): 
61          return coro.with_timeout(timeout, function, *args, **kwargs) 
62      else: 
63          # Use sigalarm to do the magic. 
64          old_sigalrm_handler = signal.signal(signal.SIGALRM, _shutdown_sigalrm_handler) 
65          try: 
66              try: 
67                  signal.alarm(timeout) 
68                  return function(*args, **kwargs) 
69              except _shutdown_sigalrm_exc: 
70                  raise coro.TimeoutError 
71          finally: 
72              signal.alarm(0) 
73              signal.signal(signal.SIGALRM, old_sigalrm_handler) 
74   
75 -def sleep_relative(delta): 
76      """Sleep for a period of time. 
77   
78      :Parameters: 
79          - `delta`: The number of seconds to sleep. 
80      """ 
81      time.sleep(delta) 
82