Source Code for Module _Framework.Signal

  1  #Embedded file name: /Users/versonator/Hudson/live/Projects/AppLive/Resources/MIDI Remote Scripts/_Framework/Signal.py 
  2  from Util import find_if, nop 
  3  from functools import partial 
  4   
  5 -def default_combiner(results): 
  6      for _ in results: 
  7          pass 
  8   
  9   
 10 -class Slot(object): 
 11   
 12 -    def __init__(self, callback = None, *a, **k): 
 13          super(Slot, self).__init__(*a, **k) 
 14          self.callback = callback 
 15   
 16 -    def __call__(self, *a, **k): 
 17          return self.callback(*a, **k) 
 18   
 19 -    def __eq__(self, other): 
 20          return id(self) == id(other) or self.callback == other 
 21   
 22   
 23 -class IdentifyingSlot(Slot): 
 24   
 25 -    def __init__(self, sender = None, *a, **k): 
 26          super(IdentifyingSlot, self).__init__(*a, **k) 
 27          self.sender = sender 
 28   
 29 -    def __call__(self, *a, **k): 
 30          self.callback(*(a + (self.sender,)), **k) 
 31   
 32   
 33 -class Signal(object): 
 34      """ 
 35      A signal object implements the observer pattern.  It can be 
 36      connected to any number of slots (i.e. callbacks). Whenever the 
 37      signal is called, all the slots are called. 
 38       
 39      The return value of this function will depend on the combiner. 
 40      The combiner takes a generator of slot results and returns a 
 41      value.  The slots whose results are not evaluated are not called. 
 42      """ 
 43   
 44 -    def __init__(self, combiner = default_combiner, sender = None, *a, **k): 
 45          super(Signal, self).__init__(*a, **k) 
 46          self._slots = [] 
 47          self._combiner = combiner 
 48   
 49 -    def connect(self, slot, in_front = False, sender = None): 
 50          """ 
 51          Connects the signal to the slot. Does nothing if the slot is 
 52          already connected. Returns the wrapper object that is used as 
 53          a slot. 
 54           
 55          If 'in_front' is True, the slot will be put first, meaning it 
 56          will be called before previously registered slots (by default 
 57          it is put last). 
 58           
 59          If 'sender' is not None, it will be passed as last ordinal 
 60          parameter to the slot when the signal is dispatched. 
 61          """ 
 62          if not callable(slot): 
 63              raise AssertionError 
 64              if slot not in self._slots: 
 65                  slot = IdentifyingSlot(sender, slot) if sender is not None else Slot(slot) 
 66                  in_front and self._slots.insert(0, slot) 
 67              else: 
 68                  self._slots.append(slot) 
 69          else: 
 70              slot = find_if(lambda x: x == slot, self._slots) 
 71          return slot 
 72   
 73 -    def disconnect(self, slot): 
 74          if slot in self._slots: 
 75              self._slots.remove(slot) 
 76   
 77 -    def disconnect_all(self): 
 78          self._slots = [] 
 79   
 80      @property 
 81 -    def count(self): 
 82          return len(self._slots) 
 83   
 84 -    def is_connected(self, slot): 
 85          return slot in self._slots 
 86   
 87 -    def __call__(self, *a, **k): 
 88          return self._combiner(_slot_notification_generator(self._slots, a, k)) 
 89   
 90   
 91 -def _slot_notification_generator(slots, args, kws): 
 92      for slot in slots: 
 93          yield slot(*args, **kws) 
 94   
 95   
 96 -def short_circuit_combiner(slot_results): 
 97      return find_if(nop, slot_results) 
 98   
 99   
100  short_circuit_signal = partial(Signal, short_circuit_combiner) 
101