[Python-checkins] r60024 - in python/trunk: Doc/library/sched.rst Lib/sched.py Misc/NEWS

Thu Jan 17 20:31:39 CET 2008

Author: raymond.hettinger
Date: Thu Jan 17 20:31:38 2008
New Revision: 60024
Modified:
 python/trunk/Doc/library/sched.rst
 python/trunk/Lib/sched.py
 python/trunk/Misc/NEWS
Log:
Issue #1861: Add read-only attribute listing upcoming events in the order they will be run.
Modified: python/trunk/Doc/library/sched.rst
==============================================================================

--- python/trunk/Doc/library/sched.rst	(original)
+++ python/trunk/Doc/library/sched.rst	Thu Jan 17 20:31:38 2008
@@ -47,7 +47,7 @@
 Scheduler Objects
 -----------------
 
-:class:`scheduler` instances have the following methods:
+:class:`scheduler` instances have the following methods and attributes:
 
 
 .. method:: scheduler.enterabs(time, priority, action, argument)
@@ -98,3 +98,8 @@
 the calling code is responsible for canceling events which are no longer
 pertinent.
 
+.. attribute:: scheduler.queue
+
+ Read-only attribute returning a list of upcoming events in the order they
+ will be run. Each event is shown as a :term:`named tuple` with the
+ following fields: time, priority, action, argument.
Modified: python/trunk/Lib/sched.py
==============================================================================
--- python/trunk/Lib/sched.py	(original)
+++ python/trunk/Lib/sched.py	Thu Jan 17 20:31:38 2008
@@ -29,14 +29,17 @@
 # XXX the global state of your particular time and delay functions.
 
 import heapq
+from collections import namedtuple
 
 __all__ = ["scheduler"]
 
+Event = namedtuple('Event', 'time, priority, action, argument')
+
 class scheduler:
 def __init__(self, timefunc, delayfunc):
 """Initialize a new instance, passing the time and delay
 functions"""
- self.queue = []
+ self._queue = []
 self.timefunc = timefunc
 self.delayfunc = delayfunc
 
@@ -47,8 +50,8 @@
 if necessary.
 
 """
- event = time, priority, action, argument
- heapq.heappush(self.queue, event)
+ event = Event(time, priority, action, argument)
+ heapq.heappush(self._queue, event)
 return event # The ID
 
 def enter(self, delay, priority, action, argument):
@@ -67,12 +70,12 @@
 If the event is not in the queue, this raises RuntimeError.
 
 """
- self.queue.remove(event)
- heapq.heapify(self.queue)
+ self._queue.remove(event)
+ heapq.heapify(self._queue)
 
 def empty(self):
 """Check whether the queue is empty."""
- return not self.queue
+ return not self._queue
 
 def run(self):
 """Execute events until the queue is empty.
@@ -97,7 +100,7 @@
 """
 # localize variable access to minimize overhead
 # and to improve thread safety
- q = self.queue
+ q = self._queue
 delayfunc = self.delayfunc
 timefunc = self.timefunc
 pop = heapq.heappop
@@ -115,3 +118,17 @@
 delayfunc(0) # Let other threads run
 else:
 heapq.heappush(event)
+
+ @property
+ def queue(self):
+ """An ordered list of upcoming events.
+
+ Events are named tuples with fields for:
+ time, priority, action, arguments
+
+ """
+ # 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))
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Thu Jan 17 20:31:38 2008
@@ -364,6 +364,9 @@
 Library
 -------
 
+- #1861: Added an attribute to the sched module which returns an ordered
+ list of upcoming events (displayed as named tuples).
+
 - #1837: The queue module now also supports a LIFO queue and a priority queue.
 
 - Issue #1831: ctypes now raises a TypeError if conflicting positional
