cola/notification.py

   1 import os
   2
   3 from cola.compat import set
   4 from cola.decorators import memoize
   5
   6
   7 debug = os.environ.get('COLA_NOTIFIER_DEBUG', False)
   8
   9
  10 @memoize
  11 def notifier():
  12     return Notifier()
  13
  14
  15 class Notifier(object):
  16     """Object for sending and receiving notification messages"""
  17
  18     def __init__(self):
  19         self.channels = {}
  20
  21     def broadcast(self, signal, *args, **opts):
  22         if debug:
  23             print ('broadcast: %s(%s, %s)' % (signal,
  24                                               args or '<empty>',
  25                                               opts or '<empty>'))
  26         self.emit(signal, *args, **opts)
  27
  28     def emit(self, signal, *args, **opts):
  29         subscribers = self.channels.get(signal, None)
  30         if not subscribers:
  31             return
  32         for fxn in subscribers:
  33             fxn(*args, **opts)
  34
  35     def connect(self, signal, callback):
  36         subscribers = self.channels.setdefault(signal, set())
  37         subscribers.add(callback)