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         #
  15         # Check for immediate stdwin event
  16         #
  17         event = stdwinq.pollevent()
  18         if event:
  19                 mainloop.dispatch(event)
  20                 return
  21         #
  22         # Use sleep for very short delays or if there are no windows
  23         #
  24         if msecs < 100 or mainloop.countwindows() == 0:
  25                 if msecs > 0:
  26                         time.sleep(msecs * 0.001)
  27                 return
  28         #
  29         # Post a timer event on an arbitrary window and wait for it
  30         #
  31         window = mainloop.anywindow()
  32         window.settimer(msecs/100)
  33         event = stdwinq.getevent()
  34         window.settimer(0)
  35         if event[0] <> WE_TIMER:
  36                 mainloop.dispatch(event)
  37
  38 def millitimer():
  39         return int(1000 * time.time())
  40
  41 q = sched.scheduler(millitimer, delayfunc)
  42
  43 # Export functions enter, enterabs and cancel just like a scheduler
  44 #
  45 enter = q.enter
  46 enterabs = q.enterabs
  47 cancel = q.cancel
  48
  49 # Emptiness check must check both queues
  50 #
  51 def empty():
  52         return q.empty() and mainloop.countwindows() == 0
  53
  54 # Run until there is nothing left to do
  55 #
  56 def run():
  57         while not empty():
  58                 if q.empty():
  59                         mainloop.dispatch(stdwinq.getevent())
  60                 else:
  61                         q.run()