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     AMEND = 'amend'
  19
  20     def __init__(self):
  21         self.channels = {}
  22
  23     def broadcast(self, signal, *args, **opts):
  24         if debug:
  25             print('broadcast: %s(%s, %s)' % (signal,
  26                                              args or '<empty>',
  27                                              opts or '<empty>'))
  28         self.emit(signal, *args, **opts)
  29
  30     def emit(self, signal, *args, **opts):
  31         subscribers = self.channels.get(signal, None)
  32         if not subscribers:
  33             return
  34         for fxn in subscribers:
  35             fxn(*args, **opts)
  36
  37     def connect(self, signal, callback):
  38         subscribers = self.channels.setdefault(signal, set())
  39         subscribers.add(callback)