waker.py

   1 from libtuer import ThreadRepeater
   2 from threading import Lock
   3
   4 SLEEP_TIME = 0.5
   5
   6 class ToBeWoken:
   7         '''a simple struct storing information about a to-be-woken function'''
   8         def __init__(self, f, period, one_shot):
   9                 self.f = f
  10                 self.period = period
  11                 self.time_since_call = 0
  12                 self.one_shot = one_shot
  13
  14 class Waker():
  15         def __init__(self):
  16                 self._tobewokens = []
  17                 self._tobewokens_lock = Lock()
  18                 self._t = ThreadRepeater(self._wake, SLEEP_TIME, name="Waker")
  19
  20         def register(self, f, time, one_shot = False):
  21                 '''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!'''
  22                 time = max(time//SLEEP_TIME, 1)
  23                 with self._tobewokens_lock:
  24                         self._tobewokens.append(ToBeWoken(f, time, one_shot))
  25
  26         def _wake(self):
  27                 with self._tobewokens_lock:
  28                         delete = []
  29                         # run the functions we ought to run
  30                         for tobewoken, idx in zip(self._tobewokens, range(len(self._tobewokens))):
  31                                 tobewoken.time_since_call += 1
  32                                 if tobewoken.time_since_call >= tobewoken.period:
  33                                         tobewoken.f()
  34                                         tobewoken.time_since_call = 0
  35                                         if tobewoken.one_shot:
  36                                                 delete.append(idx)
  37                         # delete what we have to delete - in reverse order so the indices stay valid!
  38                         delete.reverse()
  39                         for idx in delete:
  40                                 del self._tobewokens[idx]
  41
  42         def stop(self):
  43                 self._t.stop()