Revision 113359fe lib/locking.py

b/lib/locking.py
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    self.__lock.acquire()
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    try:
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      # Order is important: __find_first_pending_queue modifies __pending
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      return not (self.__find_first_pending_queue() or
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      (_, prioqueue) = self.__find_first_pending_queue()
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      return not (prioqueue or
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                  self.__pending or
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                  self.__pending_by_prio or
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                  self.__pending_shared)
......
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    while self.__pending:
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      (priority, prioqueue) = self.__pending[0]
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      if not prioqueue:
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        heapq.heappop(self.__pending)
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        del self.__pending_by_prio[priority]
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        assert priority not in self.__pending_shared
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        continue
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      if prioqueue:
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        return prioqueue
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        return (priority, prioqueue)
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    return None
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      # Remove empty queue
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      heapq.heappop(self.__pending)
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      del self.__pending_by_prio[priority]
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      assert priority not in self.__pending_shared
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    return (None, None)
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  def __is_on_top(self, cond):
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    """Checks whether the passed condition is on top of the queue.
......
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    The caller must make sure the queue isn't empty.
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    """
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    return cond == self.__find_first_pending_queue()[0]
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    (_, prioqueue) = self.__find_first_pending_queue()
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    return cond == prioqueue[0]
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  def __acquire_unlocked(self, shared, timeout, priority):
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    """Acquire a shared lock.
......
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      if not wait_condition.has_waiting():
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        prioqueue.remove(wait_condition)
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        if wait_condition.shared:
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          del self.__pending_shared[priority]
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          # Remove from list of shared acquires if it wasn't while releasing
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          # (e.g. on lock deletion)
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          self.__pending_shared.pop(priority, None)
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    return False
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......
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        self.__shr.remove(threading.currentThread())
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      # Notify topmost condition in queue
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      prioqueue = self.__find_first_pending_queue()
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      (priority, prioqueue) = self.__find_first_pending_queue()
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      if prioqueue:
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        prioqueue[0].notifyAll()
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        cond = prioqueue[0]
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        cond.notifyAll()
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        if cond.shared:
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          # Prevent further shared acquires from sneaking in while waiters are
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          # notified
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          self.__pending_shared.pop(priority, None)
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    finally:
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      self.__lock.release()

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