Source Code for Module grassyknoll.lib.ClosingQueue

 1  # XXX this should probably be written by someone who knows WTF they're doing. 
 2   
 3  from Queue import Queue, Full, Empty 
 4   
 5  __all__=['ClosingQueue', 'Closed', 'Full', 'Empty'] 
 6   
 7 -class Closed(Exception): 
 8      """exception raised when trying to put to a closed queue""" 
 9   
10 -class ClosingQueue(Queue): 
11      """a L{Queue} that can be L{close}d. 
12       
13      When the queue is closed, attempting to L{put} additional items will raise 
14      L{Closed}. 
15       
16      A newly-created queue is open. 
17      """ 
18       
19 -    def _init(self, *args, **kwargs): 
20          self._closed=False 
21          Queue._init(self, *args, **kwargs) 
22   
23 -    def closed(self): 
24          """Return True if the queue is closed, False otherwise (not reliable!).""" 
25          self.mutex.acquire() 
26          n = self._closed 
27          self.mutex.release() 
28          return n 
29       
30 -    def close(self): 
31          """close the queue to new items""" 
32          # XXX should this have block/timeout args? 
33          self.mutex.acquire() 
34          try: 
35              self._closed=True 
36          finally: 
37              self.mutex.release() 
38       
39      # XXX this introduces weirdness if the box is full *and* closed, since it 
40      # gets called after acquiring the condvar. 
41 -    def _put(self, item): 
42          if self._closed: raise Closed 
43          else: return Queue._put(self, item) 
44           
45      # XXX once the box is closed *and* empty, all further _get's should raise 
46      # Closed. Nope, that won't work, b/c we may have threads blocked in get() 
47      # before we become empty 
48