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: 6964 $" 
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 # F0.8
63 - def disconnect_by_func(self, func):
64 warnings.warn("Please call disconnectByFunction instead", 65 DeprecationWarning, stacklevel=2) 66 self.disconnectByFunction(func)
67
68 - def disconnectByFunction(self, function):
69 self.__ensureSignals() 70 71 for signalId, conn in self.__signalConnections.items(): 72 name, proc, args, kwargs = conn 73 if proc == function: 74 break 75 else: 76 raise ValueError( 77 'No signal connected to function: %r' % (function,)) 78 79 del self.__signalConnections[signalId]
80
81 - def emit(self, signalName, *args):
82 self.__ensureSignals() 83 if signalName not in self.__signals__: 84 raise ValueError('Emitting unknown signal %s' % signalName) 85 86 connections = self.__signalConnections 87 for name, proc, pargs, pkwargs in connections.values(): 88 if name == signalName: 89 try: 90 proc(self, *(args + pargs), **pkwargs) 91 except Exception, e: 92 log.warning("signalmixin", "Exception calling " 93 "signal handler %r: %s", proc, 94 log.getExceptionMessage(e))
95