Source Code for Module flumotion.common.watched

 1  # -*- Mode: Python -*- 
 2  # vi:si:et:sw=4:sts=4:ts=4 
 3  # 
 4  # Flumotion - a streaming media server 
 5  # Copyright (C) 2004,2005,2006,2007 Fluendo, S.L. (www.fluendo.com). 
 6  # All rights reserved. 
 7   
 8  # This file may be distributed and/or modified under the terms of 
 9  # the GNU General Public License version 2 as published by 
10  # the Free Software Foundation. 
11  # This file is distributed without any warranty; without even the implied 
12  # warranty of merchantability or fitness for a particular purpose. 
13  # See "LICENSE.GPL" in the source distribution for more information. 
14   
15  # Licensees having purchased or holding a valid Flumotion Advanced 
16  # Streaming Server license may use this file in accordance with the 
17  # Flumotion Advanced Streaming Server Commercial License Agreement. 
18  # See "LICENSE.Flumotion" in the source distribution for more information. 
19   
20  # Headers in this file shall remain intact. 
21   
22  """abstract data types with built-in notification support 
23  """ 
24   
25  __version__ = "$Rev: 6964 $" 
26   
27 -def _make_watched(type, *mutators): 
28      class Watched(type): 
29          def __init__(self): 
30              type.__init__(self) 
31              self.watch_id = 0 
32              self.watch_procs = {} # id -> proc 
33   
34          def watch(self, proc): 
35              self.watch_id += 1 
36              self.watch_procs[self.watch_id] = proc 
37              return self.watch_id 
38   
39          def unwatch(self, id): 
40              del self.watch_procs[id] 
41   
42          def notify_changed(self): 
43              for proc in self.watch_procs.values(): 
44                  proc(self) 
45   
46      def mutate(method): 
47          def do_mutate(self, *args, **kwargs): 
48              method(self, *args, **kwargs) 
49              self.notify_changed() 
50          setattr(Watched, method.__name__, do_mutate) 
51      for i in mutators: 
52          mutate(getattr(type, i)) 
53   
54      return Watched 
55   
56  WatchedList = _make_watched(list, 'append', 'insert', 'remove', 'pop', 
57                              'sort', 'reverse') 
58  WatchedDict = _make_watched(dict, '__setitem__', '__delitem__', 'pop', 
59                              'popitem', 'update') 
60