Source Code for Module buildbot.util.subscription

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13  # 
14  # Copyright Buildbot Team Members 
15   
16  """ 
17  Classes to handle subscriptions to event streams. 
18   
19  This will eventually (in the 0.9.x timeframe) be replaced with an 
20  implementation based on message passing.  Users should be aware they will need 
21  to rewrite any custom code that touches this module! 
22  """ 
23   
24  from twisted.python import failure, log 
25   
26 -class SubscriptionPoint(object): 
27      """ 
28      Something that can be subscribed to. 
29      """ 
30 -    def __init__(self, name): 
31          self.name = name 
32          self.subscriptions = set() 
33   
34 -    def __str__(self): 
35          return "<SubscriptionPoint '%s'>" % self.name 
36   
37 -    def subscribe(self, callback): 
38          """Add C{callback} to the subscriptions; returns a L{Subscription} 
39          instance.""" 
40          sub = Subscription(self, callback) 
41          self.subscriptions.add(sub) 
42          return sub 
43   
44 -    def deliver(self, *args, **kwargs): 
45          """ 
46          Deliver the given args and keyword args to all of the current 
47          subscribers. 
48          """ 
49          for sub in list(self.subscriptions): 
50              try: 
51                  sub.callback(*args, **kwargs) 
52              except: 
53                  log.err(failure.Failure(), 
54                          'while invoking callback %s to %s' % (sub.callback, self)) 
55   
56 -    def _unsubscribe(self, subscription): 
57          self.subscriptions.remove(subscription) 
58   
59 -class Subscription(object): 
60      """ 
61      Represents a subscription to a L{SubscriptionPoint}; use 
62      L{SubscriptionPoint.subscribe} to get an instance. 
63      """ 
64 -    def __init__(self, subpt, callback): 
65          self.subpt = subpt 
66          self.callback = callback 
67   
68 -    def unsubscribe(self): 
69          "Cancel the subscription" 
70          self.subpt._unsubscribe(self) 
71