Remove third_party/twisted_8_1

third_party/twisted_8_1/twisted/internet/task.py

-# -*- test-case-name: twisted.test.test_task -*-
-# Copyright (c) 2001-2007 Twisted Matrix Laboratories.
-# See LICENSE for details.
-
-"""
-Scheduling utility methods and classes.
-
-@author: U{Jp Calderone<mailto:exarkun@twistedmatrix.com>}
-"""
-
-__metaclass__ = type
-
-import time
-
-from zope.interface import implements
-
-from twisted.python import reflect
-
-from twisted.internet import base, defer
-from twisted.internet.interfaces import IReactorTime
-
-
-class LoopingCall:
-    """Call a function repeatedly.
-
-    If C{f} returns a deferred, rescheduling will not take place until the
-    deferred has fired. The result value is ignored.
-
-    @ivar f: The function to call.
-    @ivar a: A tuple of arguments to pass the function.
-    @ivar kw: A dictionary of keyword arguments to pass to the function.
-    @ivar clock: A provider of
-        L{twisted.internet.interfaces.IReactorTime}.  The default is
-        L{twisted.internet.reactor}. Feel free to set this to
-        something else, but it probably ought to be set *before*
-        calling L{start}.
-
-    @type _lastTime: C{float}
-    @ivar _lastTime: The time at which this instance most recently scheduled
-        itself to run.
-    """
-
-    call = None
-    running = False
-    deferred = None
-    interval = None
-    _lastTime = 0.0
-    starttime = None
-
-    def __init__(self, f, *a, **kw):
-        self.f = f
-        self.a = a
-        self.kw = kw
-        from twisted.internet import reactor
-        self.clock = reactor
-
-
-    def start(self, interval, now=True):
-        """Start running function every interval seconds.
-
-        @param interval: The number of seconds between calls.  May be
-        less than one.  Precision will depend on the underlying
-        platform, the available hardware, and the load on the system.
-
-        @param now: If True, run this call right now.  Otherwise, wait
-        until the interval has elapsed before beginning.
-
-        @return: A Deferred whose callback will be invoked with
-        C{self} when C{self.stop} is called, or whose errback will be
-        invoked when the function raises an exception or returned a
-        deferred that has its errback invoked.
-        """
-        assert not self.running, ("Tried to start an already running "
-                                  "LoopingCall.")
-        if interval < 0:
-            raise ValueError, "interval must be >= 0"
-        self.running = True
-        d = self.deferred = defer.Deferred()
-        self.starttime = self.clock.seconds()
-        self._lastTime = self.starttime
-        self.interval = interval
-        if now:
-            self()
-        else:
-            self._reschedule()
-        return d
-
-    def stop(self):
-        """Stop running function.
-        """
-        assert self.running, ("Tried to stop a LoopingCall that was "
-                              "not running.")
-        self.running = False
-        if self.call is not None:
-            self.call.cancel()
-            self.call = None
-            d, self.deferred = self.deferred, None
-            d.callback(self)
-
-    def __call__(self):
-        def cb(result):
-            if self.running:
-                self._reschedule()
-            else:
-                d, self.deferred = self.deferred, None
-                d.callback(self)
-
-        def eb(failure):
-            self.running = False
-            d, self.deferred = self.deferred, None
-            d.errback(failure)
-
-        self.call = None
-        d = defer.maybeDeferred(self.f, *self.a, **self.kw)
-        d.addCallback(cb)
-        d.addErrback(eb)
-
-
-    def _reschedule(self):
-        """
-        Schedule the next iteration of this looping call.
-        """
-        if self.interval == 0:
-            self.call = self.clock.callLater(0, self)
-            return
-
-        currentTime = self.clock.seconds()
-        # Find how long is left until the interval comes around again.
-        untilNextTime = (self._lastTime - currentTime) % self.interval
-        # Make sure it is in the future, in case more than one interval worth
-        # of time passed since the previous call was made.
-        nextTime = max(
-            self._lastTime + self.interval, currentTime + untilNextTime)
-        # If the interval falls on the current time exactly, skip it and
-        # schedule the call for the next interval.
-        if nextTime == currentTime:
-            nextTime += self.interval
-        self._lastTime = nextTime
-        self.call = self.clock.callLater(nextTime - currentTime, self)
-
-
-    def __repr__(self):
-        if hasattr(self.f, 'func_name'):
-            func = self.f.func_name
-            if hasattr(self.f, 'im_class'):
-                func = self.f.im_class.__name__ + '.' + func
-        else:
-            func = reflect.safe_repr(self.f)
-
-        return 'LoopingCall<%r>(%s, *%s, **%s)' % (
-            self.interval, func, reflect.safe_repr(self.a),
-            reflect.safe_repr(self.kw))
-
-
-
-class SchedulerStopped(Exception):
-    """
-    The operation could not complete because the scheduler was stopped in
-    progress or was already stopped.
-    """
-
-
-
-class _Timer(object):
-    MAX_SLICE = 0.01
-    def __init__(self):
-        self.end = time.time() + self.MAX_SLICE
-
-
-    def __call__(self):
-        return time.time() >= self.end
-
-
-
-_EPSILON = 0.00000001
-def _defaultScheduler(x):
-    from twisted.internet import reactor
-    return reactor.callLater(_EPSILON, x)
-
-
-
-class Cooperator(object):
-    """
-    Cooperative task scheduler.
-    """
-
-    def __init__(self,
-                 terminationPredicateFactory=_Timer,
-                 scheduler=_defaultScheduler,
-                 started=True):
-        """
-        Create a scheduler-like object to which iterators may be added.
-
-        @param terminationPredicateFactory: A no-argument callable which will
-        be invoked at the beginning of each step and should return a
-        no-argument callable which will return False when the step should be
-        terminated.  The default factory is time-based and allows iterators to
-        run for 1/100th of a second at a time.
-
-        @param scheduler: A one-argument callable which takes a no-argument
-        callable and should invoke it at some future point.  This will be used
-        to schedule each step of this Cooperator.
-
-        @param started: A boolean which indicates whether iterators should be
-        stepped as soon as they are added, or if they will be queued up until
-        L{Cooperator.start} is called.
-        """
-        self.iterators = []
-        self._metarator = iter(())
-        self._terminationPredicateFactory = terminationPredicateFactory
-        self._scheduler = scheduler
-        self._delayedCall = None
-        self._stopped = False
-        self._started = started
-
-
-    def coiterate(self, iterator, doneDeferred=None):
-        """
-        Add an iterator to the list of iterators I am currently running.
-
-        @return: a Deferred that will fire when the iterator finishes.
-        """
-        if doneDeferred is None:
-            doneDeferred = defer.Deferred()
-        if self._stopped:
-            doneDeferred.errback(SchedulerStopped())
-            return doneDeferred
-        self.iterators.append((iterator, doneDeferred))
-        self._reschedule()
-        return doneDeferred
-
-
-    def _tasks(self):
-        terminator = self._terminationPredicateFactory()
-        while self.iterators:
-            for i in self._metarator:
-                yield i
-                if terminator():
-                    return
-            self._metarator = iter(self.iterators)
-
-
-    def _tick(self):
-        """
-        Run one scheduler tick.
-        """
-        self._delayedCall = None
-        for taskObj in self._tasks():
-            iterator, doneDeferred = taskObj
-            try:
-                result = iterator.next()
-            except StopIteration:
-                self.iterators.remove(taskObj)
-                doneDeferred.callback(iterator)
-            except:
-                self.iterators.remove(taskObj)
-                doneDeferred.errback()
-            else:
-                if isinstance(result, defer.Deferred):
-                    self.iterators.remove(taskObj)
-                    def cbContinue(result, taskObj=taskObj):
-                        self.coiterate(*taskObj)
-                    result.addCallbacks(cbContinue, doneDeferred.errback)
-        self._reschedule()
-
-
-    _mustScheduleOnStart = False
-    def _reschedule(self):
-        if not self._started:
-            self._mustScheduleOnStart = True
-            return
-        if self._delayedCall is None and self.iterators:
-            self._delayedCall = self._scheduler(self._tick)
-
-
-    def start(self):
-        """
-        Begin scheduling steps.
-        """
-        self._stopped = False
-        self._started = True
-        if self._mustScheduleOnStart:
-            del self._mustScheduleOnStart
-            self._reschedule()
-
-
-    def stop(self):
-        """
-        Stop scheduling steps.  Errback the completion Deferreds of all
-        iterators which have been added and forget about them.
-        """
-        self._stopped = True
-        for iterator, doneDeferred in self.iterators:
-            doneDeferred.errback(SchedulerStopped())
-        self.iterators = []
-        if self._delayedCall is not None:
-            self._delayedCall.cancel()
-            self._delayedCall = None
-
-
-
-_theCooperator = Cooperator()
-def coiterate(iterator):
-    """
-    Cooperatively iterate over the given iterator, dividing runtime between it
-    and all other iterators which have been passed to this function and not yet
-    exhausted.
-    """
-    return _theCooperator.coiterate(iterator)
-
-
-
-class Clock:
-    """
-    Provide a deterministic, easily-controlled implementation of
-    L{IReactorTime.callLater}.  This is commonly useful for writing
-    deterministic unit tests for code which schedules events using this API.
-    """
-    implements(IReactorTime)
-
-    rightNow = 0.0
-
-    def __init__(self):
-        self.calls = []
-
-    def seconds(self):
-        """
-        Pretend to be time.time().  This is used internally when an operation
-        such as L{IDelayedCall.reset} needs to determine a a time value
-        relative to the current time.
-
-        @rtype: C{float}
-        @return: The time which should be considered the current time.
-        """
-        return self.rightNow
-
-
-    def callLater(self, when, what, *a, **kw):
-        """
-        See L{twisted.internet.interfaces.IReactorTime.callLater}.
-        """
-        dc =  base.DelayedCall(self.seconds() + when,
-                               what, a, kw,
-                               self.calls.remove,
-                               lambda c: None,
-                               self.seconds)
-        self.calls.append(dc)
-        self.calls.sort(lambda a, b: cmp(a.getTime(), b.getTime()))
-        return dc
-
-    def getDelayedCalls(self):
-        """
-        See L{twisted.internet.interfaces.IReactorTime.getDelayedCalls}
-        """
-        return self.calls
-
-    def advance(self, amount):
-        """
-        Move time on this clock forward by the given amount and run whatever
-        pending calls should be run.
-
-        @type amount: C{float}
-        @param amount: The number of seconds which to advance this clock's
-        time.
-        """
-        self.rightNow += amount
-        while self.calls and self.calls[0].getTime() <= self.seconds():
-            call = self.calls.pop(0)
-            call.called = 1
-            call.func(*call.args, **call.kw)
-
-
-    def pump(self, timings):
-        """
-        Advance incrementally by the given set of times.
-
-        @type timings: iterable of C{float}
-        """
-        for amount in timings:
-            self.advance(amount)
-
-
-def deferLater(clock, delay, callable, *args, **kw):
-    """
-    Call the given function after a certain period of time has passed.
-
-    @type clock: L{IReactorTime} provider
-    @param clock: The object which will be used to schedule the delayed
-        call.
-
-    @type delay: C{float} or C{int}
-    @param delay: The number of seconds to wait before calling the function.
-
-    @param callable: The object to call after the delay.
-
-    @param *args: The positional arguments to pass to C{callable}.
-
-    @param **kw: The keyword arguments to pass to C{callable}.
-
-    @rtype: L{defer.Deferred}
-
-    @return: A deferred that fires with the result of the callable when the
-        specified time has elapsed.
-    """
-    d = defer.Deferred()
-    d.addCallback(lambda ignored: callable(*args, **kw))
-    clock.callLater(delay, d.callback, None)
-    return d
-
-
-
-__all__ = [
-    'LoopingCall',
-
-    'Clock',
-
-    'SchedulerStopped', 'Cooperator', 'coiterate',
-
-    'deferLater',
-    ]