waker.py

   1 from libtuer import ThreadRepeater
   2 from collections import namedtuple
   3 from threading import Lock
   4
   5 SLEEP_TIME = 0.5
   6
   7 ToBeWoken = namedtuple('ToBeWoken','f period time_since_call one_shot')
   8
   9 class Waker():
  10         def __init__(self):
  11                 self._tobewokens = []
  12                 self._tobewokens_lock = Lock()
  13                 self._t = ThreadRepeater(self._wake, SLEEP_TIME, name="Waker")
  14
  15         def register(self, f, time, one_shot = False):
  16                 '''Register a function which is called approximately every <time> seconds (or just once, if one_shot is True). f should return quickly, or it will delay the waker!'''
  17                 time = max(time//SLEEP_TIME, 1)
  18                 with self._tobewokens_lock:
  19                         self._tobewokens.append(ToBeWoken(f, time, 0, one_shot))
  20
  21         def _wake(self):
  22                 with self._tobewokens_lock:
  23                         delete = []
  24                         # run the functions we ought to run
  25                         for tobewoken, idx in zip(self._tobewokens, range(len(self._tobewokens))):
  26                                 tobewoken.time_since_call += 1
  27                                 if tobewoken.time_since_call >= tobewoken.period:
  28                                         tobewoken.f()
  29                                         tobewoken.time_since_call = 0
  30                                         if tobewoken.one_shot:
  31                                                 delete.append(idx)
  32                         # delete what we have to delete - in reverse order so the indices stay valid!
  33                         delete.reverse()
  34                         for idx in delete:
  35                                 del self._tobewokens[idx]
  36
  37         def stop(self):
  38                 self._t.stop()