Package flumotion :: Package common :: Module signals
[hide private]

Source Code for Module flumotion.common.signals

 1  # -*- Mode: Python; test-case-name: flumotion.test.test_common_signals -*- 
 2  # vi:si:et:sw=4:sts=4:ts=4 
 3  # 
 4  # Flumotion - a streaming media server 
 5  # Copyright (C) 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  """synchronous message passing between python objects 
23  """ 
24   
25  import warnings 
26   
27  from flumotion.common import log 
28   
29  __version__ = "$Rev$" 
30   
31   
32 -class SignalMixin(object):
33 __signals__ = () 34 35 __signalConnections = None 36 __signalId = 0 37
38 - def __ensureSignals(self):
39 if self.__signalConnections is None: 40 self.__signalConnections = {}
41
42 - def connect(self, signalName, proc, *args, **kwargs):
43 self.__ensureSignals() 44 45 if signalName not in self.__signals__: 46 raise ValueError('Unknown signal for object of type %r: %s' 47 % (type(self), signalName)) 48 49 sid = self.__signalId 50 self.__signalConnections[sid] = (signalName, proc, args, kwargs) 51 self.__signalId += 1 52 return sid
53
54 - def disconnect(self, signalId):
55 self.__ensureSignals() 56 57 if signalId not in self.__signalConnections: 58 raise ValueError('Unknown signal ID: %s' % (signalId, )) 59 60 del self.__signalConnections[signalId]
61
62 - def disconnectByFunction(self, function):
63 self.__ensureSignals() 64 65 for signalId, conn in self.__signalConnections.items(): 66 name, proc, args, kwargs = conn 67 if proc == function: 68 break 69 else: 70 raise ValueError( 71 'No signal connected to function: %r' % (function, )) 72 73 del self.__signalConnections[signalId]
74
75 - def emit(self, signalName, *args):
76 self.__ensureSignals() 77 if signalName not in self.__signals__: 78 raise ValueError('Emitting unknown signal %s' % signalName) 79 80 connections = self.__signalConnections 81 for name, proc, pargs, pkwargs in connections.values(): 82 if name == signalName: 83 try: 84 proc(self, *(args + pargs), **pkwargs) 85 except Exception, e: 86 log.warning("signalmixin", "Exception calling " 87 "signal handler %r: %s", proc, 88 log.getExceptionMessage(e))
89