Events.py

   1 """Event handling and generation.
   2
   3 The Event module manages event generation. Events are created by
   4 EventSource instances. Each event source is associated with a file
   5 handle. This handle will be poll()'ed and the eventsource will be
   6 called, as sonn as input is available."""
   7
   8 import select, Logger, Node, Actions
   9
  10 class Event(object):
  11
  12     def __init__(self, context, code):
  13         self.context = context
  14         self.code = code
  15
  16     def __getitem__(self, index):
  17         rerturn (self.context, self.code)[index]
  18
  19     def __cmp__(self, other):
  20         return cmp(self.context, other.context) or cmp(self.code, other.code)
  21
  22     def __hash__(self):
  23         return hash(self.context) ^ hash(self.code)
  24
  25     def __str__(self):
  26         return repr((self.context, self.code))
  27
  28
  29 class ControlEvent(Event):
  30
  31     def __init__(self, context, code, value):
  32         Event.__init__(self, context, code)
  33         self.value = value
  34
  35     def __str__(self):
  36         return repr((self.context, self.code, self.value))
  37
  38
  39 class EventSource(Node.Node):
  40
  41     def __init__(self, fd, context):
  42         Node.Node.__init__(self)
  43         self._fd = fd
  44         self._context = context
  45
  46     def fd(self):
  47         return self._fd
  48
  49     def context(self):
  50         return self._context
  51
  52     def fileno(self):
  53         return self._fd.fileno()
  54
  55     def readEvents(self):
  56         raise NotImplementedError
  57
  58
  59 class Dispatcher(Node.Node):
  60
  61     _sources = Node.NodeMap()
  62
  63     def __init__(self, keylist):
  64         Node.Node.__init__(self)
  65         self._sources = {}
  66         self._callbacks = []
  67         self._keylist = keylist
  68         self._poller = select.poll()
  69         self._event = None
  70         self._interval = None
  71         self._idleCallback = None
  72
  73     def registerSource(self, eventSource):
  74         self._sources[eventSource.fileno()] = eventSource
  75         self._poller.register(eventSource.fileno(),select.POLLIN)
  76
  77     def unregisterSource(self, eventSource):
  78         del self._sources[eventSource.fileno()]
  79         self._poller.unregister(eventSource.fileno())
  80
  81     def registerCallback(self,cb):
  82         self._callbacks.append(cb)
  83
  84     def unregisterCallback(self,cb):
  85         self._callbacks.remove(cb)
  86
  87     def currentEvent(self):
  88         return self._event
  89
  90     def setIdleCallback(self, cb, interval):
  91         self._interval = interval
  92         self._idleCallback = cb
  93
  94     def unsetIdleCallback(self):
  95         self._interval = None
  96         self._idleCallback = None
  97
  98     def emit(self, event):
  99         binding = self._keylist.lookup(event)
 100         if binding is not None:
 101             self._event = event
 102             binding.execute()
 103             self._event = None
 104
 105     def run(self):
 106         while 1:
 107             for cb in self._callbacks : cb()
 108             try:
 109                 pollEvents = self._poller.poll(self._interval)
 110             except select.error, v:
 111                 if v[0]==4 : continue
 112                 else       : raise
 113             if not pollEvents and self._idleCallback:
 114                 self._idleCallback()
 115             for fd, pollEvent in pollEvents:
 116                 if pollEvent != select.POLLIN : return
 117                 for event in  self._sources[fd].readEvents():
 118                     Logger.log('dispatcher', 'event: ' + str(event))
 119                     self.emit(event)
 120
 121 class EmitEvent(Actions.Action):
 122
 123     def __init__(self, name, dispatcher, event):
 124         Actions.Action.__init__(self, name)
 125         self._dispatcher = dispatcher
 126         self._event = event
 127
 128     def __call__(self, binding):
 129         self._dispatcher.emit(self._event)