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00033 import threading
00034
00035 from python_qt_binding.QtCore import QCoreApplication, QEvent
00036 from python_qt_binding.QtCore import qWarning
00037
00038
00039 class ListenerEvent(QEvent):
00040
00041 def __init__(self, data):
00042 super(ListenerEvent, self).__init__(QEvent.User)
00043 self.data = data
00044
00045
00046 class MessageListenerThread(threading.Thread):
00047
00048 """
00049 Waits for new messages loaded on the given topic, then calls the message listener.
00050 One thread per listener, topic pair.
00051 """
00052
00053 def __init__(self, timeline, topic, listener):
00054 threading.Thread.__init__(self)
00055
00056 self.timeline = timeline
00057 self.topic = topic
00058 self.listener = listener
00059 self.bag_msg_data = None
00060 self._stop_flag = False
00061 self.setDaemon(True)
00062 self.start()
00063
00064 def run(self):
00065 """
00066 Thread body. loops and notifies the listener of new messages
00067 """
00068 while not self._stop_flag:
00069
00070 cv = self.timeline._messages_cvs[self.topic]
00071 with cv:
00072 while (self.topic not in self.timeline._messages) or (self.bag_msg_data == self.timeline._messages[self.topic]):
00073 cv.wait()
00074 if self._stop_flag:
00075 return
00076 bag_msg_data = self.timeline._messages[self.topic]
00077
00078 self.bag_msg_data = bag_msg_data
00079 try:
00080 event = ListenerEvent(bag_msg_data)
00081 QCoreApplication.postEvent(self.listener, event)
00082 except Exception as ex:
00083 qWarning('Error notifying listener %s: %s' % (type(self.listener), str(ex)))
00084
00085 def stop(self):
00086 self._stop_flag = True
00087 cv = self.timeline._messages_cvs[self.topic]
00088 with cv:
00089 cv.notify_all()