code.delx.au - bg-scripts/blob - lib/asyncsched.py

   1 # Copyright 2008 James Bunton <jamesbunton@fastmail.fm>
   2 # Licensed for distribution under the GPL version 2, check COPYING for details
   3 # asyncore.loop() with delayed function calls
   4
   5 import asyncore
   6 import time
   7 import heapq
   8
   9 tasks = []
  10
  11 class Task(object):
  12         def __init__(self, delay, func, args=[], kwargs={}):
  13                 self.time = time.time() + delay
  14                 self.func = lambda: func(*args, **kwargs)
  15
  16         def __cmp__(self, other):
  17                 return cmp(self.time, other.time)
  18
  19         def __call__(self):
  20                 f = self.func
  21                 self.func = None
  22                 if f:
  23                         return f()
  24
  25         def cancel(self):
  26                 assert self.func is not None
  27                 self.func = None
  28
  29 def schedule(delay, func, args=[], kwargs={}):
  30         task = Task(delay, func, args, kwargs)
  31         heapq.heappush(tasks, task)
  32         return task
  33
  34 def loop(timeout=30.0):
  35         while True:
  36                 now = time.time()
  37                 while tasks and tasks[0].time < now:
  38                         task = heapq.heappop(tasks)
  39                         task()
  40
  41                 t = timeout
  42                 if tasks:
  43                         t = max(min(t, tasks[0].time - now), 0)
  44
  45                 asyncore.poll(timeout=t)
  46