Lib/lib-stdwin/WindowSched.py

   1 # Combine a real-time scheduling queue and stdwin event handling.
   2 # Keeps times in milliseconds.
   3
   4 import stdwin, stdwinq
   5 from stdwinevents import WE_TIMER
   6 import mainloop
   7 import sched
   8 import time
   9
  10 # Delay function called by the scheduler when it has nothing to do.
  11 # Return immediately when something is done, or when the delay is up.
  12 #
  13 def delayfunc(msecs):
  14         msecs = int(msecs)
  15         #
  16         # Check for immediate stdwin event
  17         #
  18         event = stdwinq.pollevent()
  19         if event:
  20                 mainloop.dispatch(event)
  21                 return
  22         #
  23         # Use sleep for very short delays or if there are no windows
  24         #
  25         if msecs < 100 or mainloop.countwindows() == 0:
  26                 if msecs > 0:
  27                         time.sleep(msecs * 0.001)
  28                 return
  29         #
  30         # Post a timer event on an arbitrary window and wait for it
  31         #
  32         window = mainloop.anywindow()
  33         window.settimer(msecs/100)
  34         event = stdwinq.getevent()
  35         window.settimer(0)
  36         if event[0] <> WE_TIMER:
  37                 mainloop.dispatch(event)
  38
  39 def millitimer():
  40         return time.time() * 1000
  41
  42 q = sched.scheduler(millitimer, delayfunc)
  43
  44 # Export functions enter, enterabs and cancel just like a scheduler
  45 #
  46 enter = q.enter
  47 enterabs = q.enterabs
  48 cancel = q.cancel
  49
  50 # Emptiness check must check both queues
  51 #
  52 def empty():
  53         return q.empty() and mainloop.countwindows() == 0
  54
  55 # Run until there is nothing left to do
  56 #
  57 def run():
  58         while not empty():
  59                 if q.empty():
  60                         mainloop.dispatch(stdwinq.getevent())
  61                 else:
  62                         q.run()