diff options
Diffstat (limited to 'Lib/sched.py')
| -rw-r--r-- | Lib/sched.py | 82 |
1 files changed, 50 insertions, 32 deletions
diff --git a/Lib/sched.py b/Lib/sched.py index a119892..a89a118 100644 --- a/Lib/sched.py +++ b/Lib/sched.py @@ -28,12 +28,17 @@ has another way to reference private data (besides global variables). # XXX instead of having to define a module or class just to hold # XXX the global state of your particular time and delay functions. +import time import heapq from collections import namedtuple +try: + import threading +except ImportError: + import dummy_threading as threading __all__ = ["scheduler"] -class Event(namedtuple('Event', 'time, priority, action, argument')): +class Event(namedtuple('Event', 'time, priority, action, argument, kwargs')): def __eq__(s, o): return (s.time, s.priority) == (o.time, o.priority) def __ne__(s, o): return (s.time, s.priority) != (o.time, o.priority) def __lt__(s, o): return (s.time, s.priority) < (o.time, o.priority) @@ -42,32 +47,36 @@ class Event(namedtuple('Event', 'time, priority, action, argument')): def __ge__(s, o): return (s.time, s.priority) >= (o.time, o.priority) class scheduler: - def __init__(self, timefunc, delayfunc): + + def __init__(self, timefunc=time.time, delayfunc=time.sleep): """Initialize a new instance, passing the time and delay functions""" self._queue = [] + self._lock = threading.RLock() self.timefunc = timefunc self.delayfunc = delayfunc - def enterabs(self, time, priority, action, argument): + def enterabs(self, time, priority, action, argument=[], kwargs={}): """Enter a new event in the queue at an absolute time. Returns an ID for the event which can be used to remove it, if necessary. """ - event = Event(time, priority, action, argument) - heapq.heappush(self._queue, event) - return event # The ID + with self._lock: + event = Event(time, priority, action, argument, kwargs) + heapq.heappush(self._queue, event) + return event # The ID - def enter(self, delay, priority, action, argument): + def enter(self, delay, priority, action, argument=[], kwargs={}): """A variant that specifies the time as a relative time. This is actually the more commonly used interface. """ - time = self.timefunc() + delay - return self.enterabs(time, priority, action, argument) + with self._lock: + time = self.timefunc() + delay + return self.enterabs(time, priority, action, argument, kwargs) def cancel(self, event): """Remove an event from the queue. @@ -76,15 +85,20 @@ class scheduler: If the event is not in the queue, this raises ValueError. """ - self._queue.remove(event) - heapq.heapify(self._queue) + with self._lock: + self._queue.remove(event) + heapq.heapify(self._queue) def empty(self): """Check whether the queue is empty.""" - return not self._queue + with self._lock: + return not self._queue - def run(self): + def run(self, blocking=True): """Execute events until the queue is empty. + If blocking is False executes the scheduled events due to + expire soonest (if any) and then return the deadline of the + next scheduled call in the scheduler. When there is a positive delay until the first event, the delay function is called and the event is left in the queue; @@ -106,24 +120,27 @@ class scheduler: """ # localize variable access to minimize overhead # and to improve thread safety - q = self._queue - delayfunc = self.delayfunc - timefunc = self.timefunc - pop = heapq.heappop - while q: - time, priority, action, argument = checked_event = q[0] - now = timefunc() - if now < time: - delayfunc(time - now) - else: - event = pop(q) - # Verify that the event was not removed or altered - # by another thread after we last looked at q[0]. - if event is checked_event: - action(*argument) - delayfunc(0) # Let other threads run + with self._lock: + q = self._queue + delayfunc = self.delayfunc + timefunc = self.timefunc + pop = heapq.heappop + while q: + time, priority, action, argument, kwargs = checked_event = q[0] + now = timefunc() + if now < time: + if not blocking: + return time - now + delayfunc(time - now) else: - heapq.heappush(q, event) + event = pop(q) + # Verify that the event was not removed or altered + # by another thread after we last looked at q[0]. + if event is checked_event: + action(*argument, **kwargs) + delayfunc(0) # Let other threads run + else: + heapq.heappush(q, event) @property def queue(self): @@ -136,5 +153,6 @@ class scheduler: # Use heapq to sort the queue rather than using 'sorted(self._queue)'. # With heapq, two events scheduled at the same time will show in # the actual order they would be retrieved. - events = self._queue[:] - return map(heapq.heappop, [events]*len(events)) + with self._lock: + events = self._queue[:] + return map(heapq.heappop, [events]*len(events)) |