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Viewing changes to vendor/Twisted-10.0.0/twisted/python/timeoutqueue.py

  • Committer: Jesse Andrews
  • Date: 2010-05-28 06:05:26 UTC
  • Revision ID: git-v1:bf6e6e718cdc7488e2da87b21e258ccc065fe499
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vendor/Twisted-10.0.0/twisted/python/timeoutqueue.py
 
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# -*- test-case-name: twisted.test.test_timeoutqueue -*-
 
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# Copyright (c) 2001-2007 Twisted Matrix Laboratories.
 
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# See LICENSE for details.
 
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"""
 
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A Queue subclass that supports timeouts.
 
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"""
 
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# System Imports
 
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import Queue, time, warnings
 
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_time = time.time
 
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_sleep = time.sleep
 
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class TimedOut(Exception):
 
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    pass
 
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class TimeoutQueue(Queue.Queue):
 
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    """
 
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    A thread-safe queue that supports timeouts.
 
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    """
 
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    def __init__(self, max=0):
 
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        warnings.warn("timeoutqueue is deprecated since Twisted 8.0",
 
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                      category=DeprecationWarning, stacklevel=2)
 
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        Queue.Queue.__init__(self, max)
 
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    def wait(self, timeout):
 
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        """
 
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        Wait until the queue isn't empty. Raises TimedOut if still empty.
 
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        """
 
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        endtime = _time() + timeout
 
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        delay = 0.0005 # 500 us -> initial delay of 1 ms
 
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        while 1:
 
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            gotit = not self.empty()
 
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            if gotit:
 
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                break
 
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            remaining = endtime - _time()
 
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            if remaining <= 0:
 
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                raise TimedOut, "timed out."
 
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            delay = min(delay * 2, remaining, .05)
 
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            _sleep(delay)
 
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__all__ = ["TimeoutQueue", "TimedOut"]
 
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