panda3d/direct/src/task/Task.py

"""Undocumented Module"""

__all__ = ['Task', 'TaskPriorityList', 'TaskManager']


# This module may not import pandac.PandaModules, since it is imported
# by the Toontown Launcher before the complete PandaModules have been
# downloaded.  Instead, it imports only libpandaexpressModules, the
# subset of PandaModules that we know is available immediately.
# Methods that require more advanced C++ methods may import the
# appropriate files within their own scope.
from pandac.libpandaexpressModules import *

from direct.directnotify.DirectNotifyGlobal import *
from direct.showbase.PythonUtil import *
from direct.showbase.MessengerGlobal import *
from direct.showbase import ExceptionVarDump
import time
import fnmatch
import string
import signal
import random
try:
    Dtool_PreloadDLL("libp3heapq")
    from libp3heapq import heappush, heappop, heapify
except:
    Dtool_PreloadDLL("libheapq")
    from libheapq import heappush, heappop, heapify
import types
import gc

if __debug__:
    # For pstats
    from pandac.PandaModules import PStatCollector

def print_exc_plus():
    """
    Print the usual traceback information, followed by a listing of all the
    local variables in each frame.
    """
    import sys
    import traceback

    tb = sys.exc_info()[2]
    while 1:
        if not tb.tb_next:
            break
        tb = tb.tb_next
    stack = []
    f = tb.tb_frame
    while f:
        stack.append(f)
        f = f.f_back
    stack.reverse()
    traceback.print_exc()
    print "Locals by frame, innermost last"
    for frame in stack:
        print
        print "Frame %s in %s at line %s" % (frame.f_code.co_name,
                                             frame.f_code.co_filename,
                                             frame.f_lineno)
        for key, value in frame.f_locals.items():
            print "\t%20s = " % key,
            #We have to be careful not to cause a new error in our error
            #printer! Calling str() on an unknown object could cause an
            #error we don't want.
            try:
                print value
            except:
                print "<ERROR WHILE PRINTING VALUE>"

class Task:

    # This enum is a copy of the one at the top-level.
    exit = -1
    done = 0
    cont = 1
    again = 2

    count = 0
    def __init__(self, callback, priority = 0):
        try:
            config
        except:
            pass
        else:
            if config.GetBool('record-task-creation-stack', 0):
                self.debugInitTraceback = StackTrace("Task "+str(callback), 1, 10)
        # Unique ID for each task
        self.id = Task.count
        Task.count += 1

        #set to have the task managed
        self.owner = None

        self.__call__ = callback
        self._priority = priority
        self._removed = 0
        self.dt = 0.0
        if TaskManager.taskTimerVerbose:
            self.avgDt = 0.0
            self.maxDt = 0.0
            self.runningTotal = 0.0
            self.pstats = None
            self.pstatCollector = None
        self.extraArgs = []
        # Used for doLaters
        self.wakeTime = 0.0
        # for repeating doLaters
        self.delayTime = 0.0
        self.time = 0.0

#     # Used for putting into the doLaterList
#     # the heapq calls __cmp__ via the rich compare function
#     def __cmp__(self, other):
#         if isinstance(other, Task):
#             if self.wakeTime < other.wakeTime:
#                 return -1
#             elif self.wakeTime > other.wakeTime:
#                 return 1
#             # If the wakeTimes happen to be the same, just
#             # sort them based on id
#             else:
#                 return cmp(id(self), id(other))
#         # This is important for people doing a (task != None) and such.
#         else:
#             return cmp(id(self), id(other))

#     # According to the Python manual (3.3.1), if you define a cmp operator
#     # you should also define a hash operator or your objects will not be
#     # usable in dictionaries. Since no two task objects are unique, we can
#     # just return the unique id.
#     def __hash__(self):
#         return self.id

    def remove(self):
        if not self._removed:
            if(self.owner):
                self.owner._clearTask(self)
            self._removed = 1
            # Remove any refs to real objects
            # In case we hang around the doLaterList for a while
            del self.__call__
            del self.extraArgs
            if TaskManager.taskTimerVerbose and self.pstatCollector:
                self.pstatCollector.subLevelNow(1)

    def isRemoved(self):
        return self._removed

    def getPriority(self):
        return self._priority

    def setPriority(self, pri):
        self._priority = pri

    def setStartTimeFrame(self, startTime, startFrame):
        self.starttime = startTime
        self.startframe = startFrame

    def setCurrentTimeFrame(self, currentTime, currentFrame):
        # Calculate and store this task's time (relative to when it started)
        self.time = currentTime - self.starttime
        self.frame = currentFrame - self.startframe

    def getNamePattern(self, taskName=None):
        # get a version of the task name that doesn't contain any numbers
        digits = '0123456789'
        if taskName is None:
            taskName = self.name
        return ''.join([c for c in taskName if c not in digits])

    def setupPStats(self):
        if __debug__ and TaskManager.taskTimerVerbose and not self.pstats:
            # Get the PStats name for the task.  By convention,
            # this is everything until the first hyphen; the part
            # of the task name following the hyphen is generally
            # used to differentiate particular tasks that do the
            # same thing to different objects.
            name = self.name
            hyphen = name.find('-')
            if hyphen >= 0:
                name = name[0:hyphen]
            self.pstats = PStatCollector("App:Show code:" + name)
            if self.wakeTime or self.delayTime:
                self.pstatCollector = PStatCollector("Tasks:doLaters:" + name)
            else:
                self.pstatCollector = PStatCollector("Tasks:" + name)
            self.pstatCollector.addLevelNow(1)

    def finishTask(self, verbose):
        if hasattr(self, "uponDeath"):
            self.uponDeath(self)
            if verbose:
                # We regret to announce...
                messenger.send('TaskManager-removeTask', sentArgs = [self, self.name])
            del self.uponDeath

    def __repr__(self):
        if hasattr(self, 'name'):
            return ('Task id: %s, name %s' % (self.id, self.name))
        else:
            return ('Task id: %s, no name' % (self.id))

def pause(delayTime):
    def func(self):
        if (self.time < self.delayTime):
            return cont
        else:
            return done
    task = Task(func)
    task.name = 'pause'
    task.delayTime = delayTime
    return task
Task.pause = staticmethod(pause)

def sequence(*taskList):
    return make_sequence(taskList)
Task.sequence = staticmethod(sequence)


def make_sequence(taskList):
    def func(self):
        frameFinished = 0
        taskDoneStatus = -1
        while not frameFinished:
            task = self.taskList[self.index]
            # If this is a new task, set its start time and frame
            if self.index > self.prevIndex:
                task.setStartTimeFrame(self.time, self.frame)
            self.prevIndex = self.index
            # Calculate this task's time since it started
            task.setCurrentTimeFrame(self.time, self.frame)
            # Execute the current task
            ret = task(task)
            # Check the return value from the task
            if ret == cont:
                # If this current task wants to continue,
                # come back to it next frame
                taskDoneStatus = cont
                frameFinished = 1
            elif ret == done:
                # If this task is done, increment the index so that next frame
                # we will start executing the next task on the list
                self.index = self.index + 1
                taskDoneStatus = cont
                frameFinished = 0
            elif ret == exit:
                # If this task wants to exit, the sequence exits
                taskDoneStatus = exit
                frameFinished = 1

            # If we got to the end of the list, this sequence is done
            if self.index >= len(self.taskList):
                # TaskManager.notify.debug('sequence done: ' + self.name)
                frameFinished = 1
                taskDoneStatus = done

        return taskDoneStatus

    task = Task(func)
    task.name = 'sequence'
    task.taskList = taskList
    task.prevIndex = -1
    task.index = 0
    return task

def resetSequence(task):
    # Should this automatically be done as part of spawnTaskNamed?
    # Or should one have to create a new task instance every time
    # one wishes to spawn a task (currently sequences and can
    # only be fired off once
    task.index = 0
    task.prevIndex = -1

def loop(*taskList):
    return make_loop(taskList)
Task.loop = staticmethod(loop)

def make_loop(taskList):
    def func(self):
        frameFinished = 0
        taskDoneStatus = -1
        while (not frameFinished):
            task = self.taskList[self.index]
            # If this is a new task, set its start time and frame
            if (self.index > self.prevIndex):
                task.setStartTimeFrame(self.time, self.frame)
            self.prevIndex = self.index
            # Calculate this task's time since it started
            task.setCurrentTimeFrame(self.time, self.frame)
            # Execute the current task
            ret = task(task)
            # Check the return value from the task
            if (ret == cont):
                # If this current task wants to continue,
                # come back to it next frame
                taskDoneStatus = cont
                frameFinished = 1
            elif (ret == done):
                # If this task is done, increment the index so that next frame
                # we will start executing the next task on the list
                # TODO: we should go to the next frame now
                self.index = self.index + 1
                taskDoneStatus = cont
                frameFinished = 0
            elif (ret == exit):
                # If this task wants to exit, the sequence exits
                taskDoneStatus = exit
                frameFinished = 1
            if (self.index >= len(self.taskList)):
                # If we got to the end of the list, wrap back around
                self.prevIndex = -1
                self.index = 0
                frameFinished = 1
        return taskDoneStatus
    task = Task(func)
    task.name = 'loop'
    task.taskList = taskList
    task.prevIndex = -1
    task.index = 0
    return task


class TaskPriorityList(list):
    def __init__(self, priority):
        self._priority = priority
        self.__emptyIndex = 0
    def getPriority(self):
        return self._priority
    def add(self, task):
        if (self.__emptyIndex >= len(self)):
            self.append(task)
            self.__emptyIndex += 1
        else:
            self[self.__emptyIndex] = task
            self.__emptyIndex += 1
    def remove(self, i):
        assert i <= len(self)
        if (len(self) == 1) and (i == 1):
            self[i] = None
            self.__emptyIndex = 0
        else:
            # Swap the last element for this one
            lastElement = self[self.__emptyIndex-1]
            self[i] = lastElement
            self[self.__emptyIndex-1] = None
            self.__emptyIndex -= 1

class GCTrigger:
    # used to trigger garbage collection
    pass

class TaskManager:

    # These class vars are generally overwritten by Config variables which
    # are read in at the start of a show (ShowBase.py or AIStart.py)

    notify = None
    # TODO: there is a bit of a bug when you default this to 0. The first
    # task we make, the doLaterProcessor, needs to have this set to 1 or
    # else we get an error.
    taskTimerVerbose = 1
    extendedExceptions = 0
    pStatsTasks = 0

    doLaterCleanupCounter = 2000

    OsdPrefix = 'task.'

    GarbageCollectTaskName = "allowGarbageCollect"

    # multiple of average frame duration
    DefTaskDurationWarningThreshold = 40.

    _DidTests = False

    def __init__(self):
        self.running = 0
        self.stepping = 0
        self.taskList = []
        # Dictionary of priority to newTaskLists
        self.pendingTaskDict = {}
        # List of tasks scheduled to execute in the future
        self.__doLaterList = []

        self._profileFrames = False
        self.MaxEpockSpeed = 1.0/30.0;   

        # this will be set when it's safe to import StateVar
        self._profileTasks = None
        self._taskProfiler = None
        self._profileInfo = ScratchPad(
            taskId = None,
            dt = None,
            lastProfileResultString = None,
            )

        # We copy this value in from __builtins__ when it gets set.
        # But since the TaskManager might have to run before it gets
        # set--before it can even be available--we also have to have
        # special-case code that handles the possibility that we don't
        # have a globalClock yet.
        self.globalClock = None

        # To help cope with the possibly-missing globalClock, we get a
        # handle to Panda's low-level TrueClock object for measuring
        # small intervals.
        self.trueClock = TrueClock.getGlobalPtr()

        # We don't have a base yet, but we can query the config
        # variables directly.
        self.warnTaskDuration = ConfigVariableBool('want-task-duration-warnings', 1).getValue()
        self.taskDurationWarningThreshold = ConfigVariableDouble(
            'task-duration-warning-threshold',
            TaskManager.DefTaskDurationWarningThreshold).getValue()

        self.currentTime, self.currentFrame = self.__getTimeFrame()
        if (TaskManager.notify == None):
            TaskManager.notify = directNotify.newCategory("TaskManager")
        self.fKeyboardInterrupt = 0
        self.interruptCount = 0
        self.resumeFunc = None
        self.fVerbose = 0
        # Dictionary of task name to list of tasks with that name
        self.nameDict = {}

        # A default task.
        self._doLaterTask = self.add(self.__doLaterProcessor, "doLaterProcessor", -10)

        # start this when config is available
        self._gcTask = None
        self._wantGcTask = None

    def destroy(self):
        if self._gcTask:
            self._gcTask.remove()
        if self._doLaterTask:
            self._doLaterTask.remove()
        if self._taskProfiler:
            self._taskProfiler.destroy()
        del self.nameDict
        del self.trueClock
        del self.globalClock
        del self.__doLaterList
        del self.pendingTaskDict
        del self.taskList

    def setStepping(self, value):
        self.stepping = value

    def setVerbose(self, value):
        self.fVerbose = value
        messenger.send('TaskManager-setVerbose', sentArgs = [value])

    def getTaskDurationWarningThreshold(self):
        return self.taskDurationWarningThreshold

    def setTaskDurationWarningThreshold(self, threshold):
        self.taskDurationWarningThreshold = threshold

    def invokeDefaultHandler(self, signalNumber, stackFrame):
        print '*** allowing mid-frame keyboard interrupt.'
        # Restore default interrupt handler
        signal.signal(signal.SIGINT, signal.default_int_handler)
        # and invoke it
        raise KeyboardInterrupt

    def keyboardInterruptHandler(self, signalNumber, stackFrame):
        self.fKeyboardInterrupt = 1
        self.interruptCount += 1
        if self.interruptCount == 1:
            print '* interrupt by keyboard'
        elif self.interruptCount == 2:
            print '** waiting for end of frame before interrupting...'
            # The user must really want to interrupt this process
            # Next time around invoke the default handler
            signal.signal(signal.SIGINT, self.invokeDefaultHandler)

    def hasTaskNamed(self, taskName):
        # TODO: check pending task list
        # Get the tasks with this name
        # If we found some, see if any of them are still active (not removed)
        for task in self.nameDict.get(taskName, []):
            if not task._removed:
                return 1
        # Didnt find any, return 0
        return 0

    def getTasksNamed(self, taskName):
        # TODO: check pending tasks
        # Get the tasks with this name
        return [task for task in self.nameDict.get(taskName, []) #grab all tasks with name
                   if not task._removed] #filter removed tasks

    def __doLaterFilter(self):
        # Filter out all the tasks that have been removed like a mark and
        # sweep garbage collector. Returns the number of tasks that have
        # been removed Warning: this creates an entirely new doLaterList.
        oldLen = len(self.__doLaterList)
        # grab all the tasks being removed so we can remove them from the nameDict
        # TODO: would be more efficient to remove from nameDict in task.remove()
        removedTasks = [task for task in self.__doLaterList
                        if task._removed]
        self.__doLaterList = [task for task in self.__doLaterList #grab all tasks with name
                              if not task._removed] #filter removed tasks
        for task in removedTasks:
            self.__removeTaskFromNameDict(task)
        # Re heapify to maintain ordering after filter
        heapify(self.__doLaterList)
        newLen = len(self.__doLaterList)
        return oldLen - newLen
        
    def __getNextDoLaterTime(self):
        if self.__doLaterList:                        
            dl = self.__doLaterList[0]
            return dl.wakeTime
        return -1;
                       

    def __doLaterProcessor(self, task):
        # Removing the tasks during the for loop is a bad idea
        # Instead we just flag them as removed
        # Later, somebody else cleans them out
        currentTime = self.__getTime()
        while self.__doLaterList:
            # Check the first one on the list to see if it is ready
            dl = self.__doLaterList[0]
            if dl._removed:
                # Get rid of this task forever
                heappop(self.__doLaterList)
                continue
            # If the time now is less than the start of the doLater + delay
            # then we are not ready yet, continue to next one
            elif currentTime < dl.wakeTime:
                # Since the list is sorted, the first one we get to, that
                # is not ready to go, we can return
                break
            else:
                # Take it off the doLaterList, set its time, and make
                # it pending
                heappop(self.__doLaterList)
                dl.setStartTimeFrame(self.currentTime, self.currentFrame)
                self.__addPendingTask(dl)
                continue
            
        # Every nth pass, let's clean out the list of removed tasks
        # This is basically a mark and sweep garbage collection of doLaters
        if ((task.frame % self.doLaterCleanupCounter) == 0):
            numRemoved = self.__doLaterFilter()
            # TaskManager.notify.debug("filtered %s removed doLaters" % numRemoved)
        return cont

    def _garbageCollect(self, task=None):
        # enable automatic garbage collection
        gc.enable()
        # creating an object with gc enabled causes garbage collection to trigger if appropriate
        gct = GCTrigger()
        # disable the automatic garbage collect during the rest of the frame
        gc.disable()
        return cont

    def doMethodLater(self, delayTime, funcOrTask, name, extraArgs=None,
                      priority=0, uponDeath=None, appendTask=False, owner = None):
        if delayTime < 0:
            assert self.notify.warning('doMethodLater: added task: %s with negative delay: %s' % (name, delayTime))
        if isinstance(funcOrTask, Task):
            task = funcOrTask
        elif callable(funcOrTask):
            task = Task(funcOrTask, priority)
        else:
            self.notify.error('doMethodLater: Tried to add a task that was not a Task or a func')
        assert isinstance(name, str), 'Name must be a string type'
        task.setPriority(priority)
        task.name = name
        task.owner = owner
        if extraArgs == None:
            extraArgs = []
            appendTask = True

        # if told to, append the task object to the extra args list so the
        # method called will be able to access any properties on the task
        if appendTask:
            extraArgs.append(task)
          
        task.extraArgs = extraArgs
        if uponDeath:
            task.uponDeath = uponDeath

        # TaskManager.notify.debug('spawning doLater: %s' % (task))
        # Add this task to the nameDict
        nameList = self.nameDict.get(name)
        if nameList:
            nameList.append(task)
        else:
            self.nameDict[name] = [task]
        currentTime = self.__getTime()
        # Cache the time we should wake up for easier sorting
        task.delayTime = delayTime
        task.wakeTime = currentTime + delayTime
        # Push this onto the doLaterList. The heap maintains the sorting.
        heappush(self.__doLaterList, task)
        if self.fVerbose:
            # Alert the world, a new task is born!
            messenger.send('TaskManager-spawnDoLater',
                           sentArgs = [task, task.name, task.id])
        return task

    def add(self, funcOrTask, name, priority=0, extraArgs=None, uponDeath=None,
            appendTask = False, owner = None):
        
        """
        Add a new task to the taskMgr.
        You can add a Task object or a method that takes one argument.
        """
        # TaskManager.notify.debug('add: %s' % (name))
        if isinstance(funcOrTask, Task):
            task = funcOrTask
        elif callable(funcOrTask):
            task = Task(funcOrTask, priority)
        else:
            self.notify.error(
                'add: Tried to add a task that was not a Task or a func')
        assert isinstance(name, str), 'Name must be a string type'
        task.setPriority(priority)
        task.name = name
        task.owner = owner
        if extraArgs == None:
            extraArgs = []
            appendTask = True

        # if told to, append the task object to the extra args list so the
        # method called will be able to access any properties on the task
        if appendTask:
            extraArgs.append(task)

        task.extraArgs = extraArgs
        if uponDeath:
            task.uponDeath = uponDeath
        currentTime = self.__getTime()
        task.setStartTimeFrame(currentTime, self.currentFrame)
        nameList = self.nameDict.get(name)
        if nameList:
            nameList.append(task)
        else:
            self.nameDict[name] = [task]
        # Put it on the list for the end of this frame
        self.__addPendingTask(task)
        return task

    def __addPendingTask(self, task):
        # TaskManager.notify.debug('__addPendingTask: %s' % (task.name))
        pri = task._priority
        taskPriList = self.pendingTaskDict.get(pri)
        if not taskPriList:
            taskPriList = TaskPriorityList(pri)
            self.pendingTaskDict[pri] = taskPriList
        taskPriList.add(task)

    def __addNewTask(self, task):
        # The taskList is really an ordered list of TaskPriorityLists
        # search back from the end of the list until we find a
        # taskList with a lower priority, or we hit the start of the list
        taskPriority = task._priority
        index = len(self.taskList) - 1
        while (1):
            if (index < 0):
                newList = TaskPriorityList(taskPriority)
                newList.add(task)
                # Add the new list to the beginning of the taskList
                self.taskList.insert(0, newList)
                break
            taskListPriority = self.taskList[index]._priority
            if (taskListPriority == taskPriority):
                self.taskList[index].add(task)
                break
            elif (taskListPriority > taskPriority):
                index = index - 1
            elif (taskListPriority < taskPriority):
                # Time to insert
                newList = TaskPriorityList(taskPriority)
                newList.add(task)
                # Insert this new priority level
                # If we are already at the end, just append it
                if (index == len(self.taskList)-1):
                    self.taskList.append(newList)
                else:
                    # Otherwise insert it
                    self.taskList.insert(index+1, newList)
                break

        if __debug__:
            if self.pStatsTasks and task.name != "igLoop":                
                task.setupPStats()
        if self.fVerbose:
            # Alert the world, a new task is born!
            messenger.send(
                'TaskManager-spawnTask', sentArgs = [task, task.name, index])
        return task

    def remove(self, taskOrName):
        if type(taskOrName) == type(''):
            return self.__removeTasksNamed(taskOrName)
        elif isinstance(taskOrName, Task):
            return self.__removeTasksEqual(taskOrName)
        else:
            self.notify.error('remove takes a string or a Task')

    def removeTasksMatching(self, taskPattern):
        """removeTasksMatching(self, string taskPattern)

        Removes tasks whose names match the pattern, which can include
        standard shell globbing characters like *, ?, and [].
        """
        # TaskManager.notify.debug('removing tasks matching: ' + taskPattern)
        num = 0
        keyList = filter(
            lambda key: fnmatch.fnmatchcase(key, taskPattern),
            self.nameDict.keys())
        for key in keyList:
            num += self.__removeTasksNamed(key)
        return num

    def __removeTasksEqual(self, task):
        # Remove this task from the nameDict (should be a short list)
        if self.__removeTaskFromNameDict(task):
            # TaskManager.notify.debug(
            #    '__removeTasksEqual: removing task: %s' % (task))
            # Flag the task for removal from the real list
            task.remove()
            task.finishTask(self.fVerbose)
            return 1
        else:
            return 0

    def __removeTasksNamed(self, taskName):
        tasks = self.nameDict.get(taskName)
        if not tasks:
            return 0
        # TaskManager.notify.debug(
        #    '__removeTasksNamed: removing tasks named: %s' % (taskName))
        for task in tasks:
            # Flag for removal
            task.remove()
            task.finishTask(self.fVerbose)
        # Record the number of tasks removed
        num = len(tasks)
        # Blow away the nameDict entry completely
        del self.nameDict[taskName]
        return num

    def __removeTaskFromNameDict(self, task):
        taskName = task.name
        # If this is the only task with that name, remove the dict entry
        tasksWithName = self.nameDict.get(taskName)
        if tasksWithName:
            if task in tasksWithName:
                # If this is the last element, just remove the entry
                # from the dictionary
                if len(tasksWithName) == 1:
                    del self.nameDict[taskName]
                else:
                    tasksWithName.remove(task)
                return 1
        return 0

    def __executeTask(self, task):
        task.setCurrentTimeFrame(self.currentTime, self.currentFrame)
        
        # cache reference to profile info here, self._profileInfo might get swapped out
        # by the task when it runs
        profileInfo = self._profileInfo
        doProfile = (task.id == profileInfo.taskId)
        
        if not self.taskTimerVerbose:
            startTime = self.trueClock.getShortTime()
            
            # don't record timing info
            if doProfile:
                ret = profile(Functor(task, *task.extraArgs),
                              'TASK_PROFILE:%s' % task.name, True, log=False)
            else:
                ret = task(*task.extraArgs)
            endTime = self.trueClock.getShortTime()
            
            # Record the dt
            dt = endTime - startTime
            if doProfile:
                # if we profiled, record the measured duration but don't pollute the task's
                # normal duration
                profileInfo.dt = dt
                dt = task.avgDt
            task.dt = dt

        else:
            # Run the task and check the return value
            if task.pstats:
                task.pstats.start()
            startTime = self.trueClock.getShortTime()
            if doProfile:
                ret = profile(Functor(task, *task.extraArgs),
                              'profiled-task-%s' % task.name, True, log=False)
            else:
                ret = task(*task.extraArgs)
            endTime = self.trueClock.getShortTime()
            if task.pstats:
                task.pstats.stop()

            # Record the dt
            dt = endTime - startTime
            if doProfile:
                # if we profiled, record the measured duration but don't pollute the task's
                # normal duration
                profileInfo.dt = dt
                dt = task.avgDt
            task.dt = dt

            # See if this is the new max
            if dt > task.maxDt:
                task.maxDt = dt

            # Record the running total of all dts so we can compute an average
            task.runningTotal = task.runningTotal + dt
            if (task.frame > 0):
                task.avgDt = (task.runningTotal / task.frame)
            else:
                task.avgDt = 0

        if doProfile:
            profileInfo.lastProfileResultString = self._getProfileResultString()

        # warn if the task took too long
        if self.warnTaskDuration and self.globalClock:
            avgFrameRate = self.globalClock.getAverageFrameRate()
            if avgFrameRate > .00001:
                avgFrameDur = (1. / avgFrameRate)
                if dt >= (self.taskDurationWarningThreshold * avgFrameDur):
                    assert TaskManager.notify.warning('frame %s: task %s ran for %.2f seconds, avg frame duration=%.2f seconds' % (
                        globalClock.getFrameCount(), task.name, dt, avgFrameDur))
            
        return ret

    def __repeatDoMethod(self, task):
        """
        Called when a task execute function returns Task.again because
        it wants the task to execute again after the same or a modified
        delay (set 'delayTime' on the task object to change the delay)
        """
        if (not task._removed):
            # be sure to ask the globalClock for the current frame time
            # rather than use a cached value; globalClock's frame time may
            # have been synced since the start of this frame
            currentTime = self.__getTime()
            # Cache the time we should wake up for easier sorting
            task.wakeTime = currentTime + task.delayTime
            # Push this onto the doLaterList. The heap maintains the sorting.
            heappush(self.__doLaterList, task)
            if self.fVerbose:
                # Alert the world, a new task is born!
                messenger.send('TaskManager-againDoLater',
                               sentArgs = [task, task.name, task.id])

    def __stepThroughList(self, taskPriList):
        # Traverse the taskPriList with an iterator
        i = 0
        while (i < len(taskPriList)):
            task = taskPriList[i]
            # See if we are at the end of the real tasks
            if task is None:
                break
            # See if this task has been removed in show code
            if task._removed:
                # assert TaskManager.notify.debug(
                #    '__stepThroughList: task is flagged for removal %s' % (task))
                # If it was removed in show code, it will need finishTask run
                # If it was removed by the taskMgr, it will not, but that is ok
                # because finishTask is safe to call twice
                task.finishTask(self.fVerbose)
                taskPriList.remove(i)
                self.__removeTaskFromNameDict(task)
                # Do not increment the iterator
                continue
            # Now actually execute the task
            ret = self.__executeTask(task)
            # See if the task is done
            if (ret == cont):
                # Leave it for next frame, its not done yet
                pass
            elif (ret == again):
                # repeat doLater again after a delay
                self.__repeatDoMethod(task)
                taskPriList.remove(i)
                continue
            elif ((ret == done) or (ret == exit) or (ret == None)):
                # assert TaskManager.notify.debug(
                #    '__stepThroughList: task is finished %s' % (task))
                # Remove the task
                if not task._removed:
                    # assert TaskManager.notify.debug(
                    #    '__stepThroughList: task not removed %s' % (task))
                    task.remove()
                    # Note: Should not need to remove from doLaterList here
                    # because this task is not in the doLaterList
                    task.finishTask(self.fVerbose)
                    self.__removeTaskFromNameDict(task)
                else:
                    # assert TaskManager.notify.debug(
                    #    '__stepThroughList: task already removed %s' % (task))
                    self.__removeTaskFromNameDict(task)
                taskPriList.remove(i)
                # Do not increment the iterator
                continue
            else:
                raise StandardError, \
                    "Task named %s did not return cont, exit, done, or None" % \
                    (task.name,)
            # Move to the next element
            i += 1

    def __addPendingTasksToTaskList(self):
        # Now that we are all done, add any left over pendingTasks
        # generated in priority levels lower or higher than where
        # we were when we iterated
        for taskList in self.pendingTaskDict.values():
            for task in taskList:
                if (task and not task._removed):
                    # assert TaskManager.notify.debug(
                    #    'step: moving %s from pending to taskList' % (task.name))
                    self.__addNewTask(task)
        self.pendingTaskDict.clear()

    def profileFrames(self, num=None):
        self._profileFrames = True
        if num is None:
            num = 1
        self._profileFrameCount = num
    

    # in the event we want to do frame time managment.. this is the function to 
    #  replace or overload..        
    def  doYield(self , frameStartTime, nextScheuledTaksTime):
          None
          
    def  doYieldExample(self , frameStartTime, nextScheuledTaksTime):
        minFinTime = frameStartTime + self.MaxEpockSpeed
        if nextScheuledTaksTime > 0 and nextScheuledTaksTime < minFinTime:
            print ' Adjusting Time'
            minFinTime = nextScheuledTaksTime;
        delta = minFinTime - self.globalClock.getRealTime();
        while(delta > 0.002):
            print ' sleep %s'% (delta)
            time.sleep(delta)           
            delta = minFinTime - self.globalClock.getRealTime();
    

    @profiled()
    def _doProfiledFrames(self, *args, **kArgs):
        print '** profiling %s frames' % self._profileFrameCount
        for i in xrange(self._profileFrameCount):
            result = self.step(*args, **kArgs)
        return result

    def getProfileTasks(self):
        return self._profileTasks.get()

    def getProfileTasksSV(self):
        return self._profileTasks

    def setProfileTasks(self, profileTasks):
        self._profileTasks.set(profileTasks)
        if (not self._taskProfiler) and profileTasks:
            # import here due to import dependencies
            from direct.task.TaskProfiler import TaskProfiler
            self._taskProfiler = TaskProfiler()

    def _setProfileTask(self, task):
        self._profileInfo = ScratchPad(
            taskId = task.id,
            dt = None,
            lastProfileResultString = None,
            )

    def _getTaskProfileDt(self):
        return self._profileInfo.dt

    def _getLastProfileResultString(self):
        return self._profileInfo.lastProfileResultString

    def _getRandomTask(self):
        numTasks = 0
        for name in self.nameDict.iterkeys():
            numTasks += len(self.nameDict[name])
        numDoLaters = len(self.__doLaterList)
        if random.random() < (numDoLaters / float(numTasks + numDoLaters)):
            # grab a doLater that will most likely trigger in the next frame
            tNow = globalClock.getFrameTime()
            avgFrameRate = globalClock.getAverageFrameRate()
            if avgFrameRate < .00001:
                avgFrameDur = 0.
            else:
                avgFrameDur = (1. / globalClock.getAverageFrameRate())
            tNext = tNow + avgFrameDur
            # binary search to find doLaters that are likely to trigger on the next frame
            curIndex = int(numDoLaters / 2)
            rangeStart = 0
            rangeEnd = numDoLaters
            while True:
                if tNext < self.__doLaterList[curIndex].wakeTime:
                    rangeEnd = curIndex
                else:
                    rangeStart = curIndex
                prevIndex = curIndex
                curIndex = int((rangeStart + rangeEnd) / 2)
                if curIndex == prevIndex:
                    break
            index = curIndex
            task = self.__doLaterList[random.randrange(index+1)]
        else:
            # grab a task
            name = random.choice(self.nameDict.keys())
            task = random.choice(self.nameDict[name])
        return task

    def step(self):
        # assert TaskManager.notify.debug('step: begin')
        self.currentTime, self.currentFrame = self.__getTimeFrame()
        startFrameTime = None
        if self.globalClock:
            startFrameTime = self.globalClock.getRealTime()
            
        # Replace keyboard interrupt handler during task list processing
        # so we catch the keyboard interrupt but don't handle it until
        # after task list processing is complete.
        self.fKeyboardInterrupt = 0
        self.interruptCount = 0
        signal.signal(signal.SIGINT, self.keyboardInterruptHandler)

        # Traverse the task list in order because it is in priority order
        priIndex = 0
        while priIndex < len(self.taskList):
            taskPriList = self.taskList[priIndex]
            pri = taskPriList._priority
            # assert TaskManager.notify.debug(
            #    'step: running through taskList at pri: %s, priIndex: %s' %
            #    (pri, priIndex))
            self.__stepThroughList(taskPriList)

            # Now see if that generated any pending tasks for this taskPriList
            pendingTasks = self.pendingTaskDict.get(pri)
            while pendingTasks:
                # assert TaskManager.notify.debug('step: running through pending tasks at pri: %s' % (pri))
                # Remove them from the pendingTaskDict
                del self.pendingTaskDict[pri]
                # Execute them
                self.__stepThroughList(pendingTasks)
                # Add these to the real taskList
                for task in pendingTasks:
                    if (task and not task._removed):
                        # assert TaskManager.notify.debug('step: moving %s from pending to taskList' % (task.name))
                        self.__addNewTask(task)
                # See if we generated any more for this pri level
                pendingTasks = self.pendingTaskDict.get(pri)

            # Any new tasks that were made pending should be converted
            # to real tasks now in case they need to run this frame at a
            # later priority level
            self.__addPendingTasksToTaskList()

            # Go to the next priority level
            priIndex += 1

        # Add new pending tasks
        self.__addPendingTasksToTaskList()
        
        if startFrameTime:
            #this is the spot for a Internal Yield Function
            nextTaskTime = self.__getNextDoLaterTime()
            self.doYield(startFrameTime,nextTaskTime)            
        
        # Restore default interrupt handler
        signal.signal(signal.SIGINT, signal.default_int_handler)
        if self.fKeyboardInterrupt:
            raise KeyboardInterrupt


    def run(self):
        # do things that couldn't be done earlier because of import dependencies
        if (not TaskManager._DidTests) and __debug__:
            TaskManager._DidTests = True
            self._runTests()

        if not self._gcTask:
            if self._wantGcTask is None:
                self._wantGcTask = config.GetBool('want-garbage-collect-task', 1)
            if self._wantGcTask:
                # manual garbage-collect task
                self._gcTask = self.add(self._garbageCollect, TaskManager.GarbageCollectTaskName, 200)

        if not self._profileTasks:
            from direct.fsm.StatePush import StateVar
            self._profileTasks = StateVar(False)
            self.setProfileTasks(getBase().config.GetBool('profile-task-spikes', 0))

        # Set the clock to have last frame's time in case we were
        # Paused at the prompt for a long time
        if self.globalClock:
            t = self.globalClock.getFrameTime()
            timeDelta = t - globalClock.getRealTime()
            self.globalClock.setRealTime(t)
            messenger.send("resetClock", [timeDelta])

        if self.resumeFunc != None:
            self.resumeFunc()

        if self.stepping:
            self.step()
        else:
            self.running = 1
            while self.running:
                try:
                    if self._profileFrames:
                        self._profileFrames = False
                        self._doProfiledFrames()
                    else:
                        self.step()
                except KeyboardInterrupt:
                    self.stop()
                except IOError, ioError:
                    code, message = self._unpackIOError(ioError)
                    # Since upgrading to Python 2.4.1, pausing the execution
                    # often gives this IOError during the sleep function:
                    #     IOError: [Errno 4] Interrupted function call
                    # So, let's just handle that specific exception and stop.
                    # All other IOErrors should still get raised.
                    # Only problem: legit IOError 4s will be obfuscated.
                    if code == 4:
                        self.stop()
                    else:
                        raise
                except Exception, e:
                    if self.extendedExceptions:
                        self.stop()
                        print_exc_plus()
                    else:
                        if (ExceptionVarDump.wantVariableDump and
                            ExceptionVarDump.dumpOnExceptionInit):
                            ExceptionVarDump._varDump__print(e)
                        raise
                except:
                    if self.extendedExceptions:
                        self.stop()
                        print_exc_plus()
                    else:
                        raise

    def _unpackIOError(self, ioError):
        # IOError unpack from http://www.python.org/doc/essays/stdexceptions/
        # this needs to be in its own method, exceptions that occur inside
        # a nested try block are not caught by the inner try block's except
        try:
            (code, message) = ioError
        except:
            code = 0
            message = ioError
        return code, message

    def stop(self):
        # Set a flag so we will stop before beginning next frame
        self.running = 0

    def __tryReplaceTaskMethod(self, task, oldMethod, newFunction):
        if (task is None) or task._removed:
            return 0
        method = task.__call__
        if (type(method) == types.MethodType):
            function = method.im_func
        else:
            function = method
        #print ('function: ' + `function` + '\n' +
        #       'method: ' + `method` + '\n' +
        #       'oldMethod: ' + `oldMethod` + '\n' +
        #       'newFunction: ' + `newFunction` + '\n')
        if (function == oldMethod):
            import new
            newMethod = new.instancemethod(newFunction,
                                           method.im_self,
                                           method.im_class)
            task.__call__ = newMethod
            # Found a match
            return 1
        return 0

    def replaceMethod(self, oldMethod, newFunction):
        numFound = 0
        # Look through the regular tasks
        for taskPriList in self.taskList:
            for task in taskPriList:
                if task:
                    numFound += self.__tryReplaceTaskMethod(task, oldMethod, newFunction)
        # Look through the pending tasks
        for pri, taskList in self.pendingTaskDict.items():
            for task in taskList:
                if task:
                    numFound += self.__tryReplaceTaskMethod(task, oldMethod, newFunction)
        # Look through the doLaters
        for task in self.__doLaterList:
            if task:
                numFound += self.__tryReplaceTaskMethod(task, oldMethod, newFunction)
        return numFound

    def __repr__(self):
        taskNameWidth = 32
        dtWidth = 10
        priorityWidth = 10
        totalDt = 0
        totalAvgDt = 0
        str = "The taskMgr is handling:\n"
        str += ('taskList'.ljust(taskNameWidth)
               + 'dt(ms)'.rjust(dtWidth)
               + 'avg'.rjust(dtWidth)
               + 'max'.rjust(dtWidth)
               + 'priority'.rjust(priorityWidth)
               + '\n')
        str += '-------------------------------------------------------------------------\n'
        dtfmt = '%%%d.2f' % (dtWidth)
        for taskPriList in self.taskList:
            priority = `taskPriList._priority`
            for task in taskPriList:
                if task is None:
                    break
                if task._removed:
                    taskName = '(R)' + task.name
                else:
                    taskName = task.name
                if self.taskTimerVerbose:
                    totalDt = totalDt + task.dt
                    totalAvgDt = totalAvgDt + task.avgDt
                    str += (taskName.ljust(taskNameWidth)
                            + dtfmt % (task.dt*1000)
                            + dtfmt % (task.avgDt*1000)
                            + dtfmt % (task.maxDt*1000)
                            + priority.rjust(priorityWidth)
                            + '\n')
                else:
                    str += (task.name.ljust(taskNameWidth)
                            + '----'.rjust(dtWidth)
                            + '----'.rjust(dtWidth)
                            + '----'.rjust(dtWidth)
                            + priority.rjust(priorityWidth)
                            + '\n')
        str += '-------------------------------------------------------------------------\n'
        str += 'pendingTasks\n'
        str += '-------------------------------------------------------------------------\n'
        for pri, taskList in self.pendingTaskDict.items():
            for task in taskList:
                if task._removed:
                    taskName = '(PR)' + task.name
                else:
                    taskName = '(P)' + task.name
                if (self.taskTimerVerbose):
                    str += ('  ' + taskName.ljust(taskNameWidth-2)
                            +  dtfmt % (pri)
                            + '\n')
                else:
                    str += ('  ' + taskName.ljust(taskNameWidth-2)
                            +  '----'.rjust(dtWidth)
                            + '\n')
        str += '-------------------------------------------------------------------------\n'
        if (self.taskTimerVerbose):
            str += ('total'.ljust(taskNameWidth)
                    + dtfmt % (totalDt*1000)
                    + dtfmt % (totalAvgDt*1000)
                    + '\n')
        else:
            str += ('total'.ljust(taskNameWidth)
                    + '----'.rjust(dtWidth)
                    + '----'.rjust(dtWidth)
                    + '\n')
        str += '-------------------------------------------------------------------------\n'
        str += ('doLaterList'.ljust(taskNameWidth)
               + 'waitTime(s)'.rjust(dtWidth)
               + '\n')
        str += '-------------------------------------------------------------------------\n'
        # When we print, show the doLaterList in actual sorted order.
        # The priority heap is not actually in order - it is a tree
        # Make a shallow copy so we can sort it
        sortedDoLaterList = self.__doLaterList[:]
        sortedDoLaterList.sort(lambda a, b: cmp(a.wakeTime, b.wakeTime))
        sortedDoLaterList.reverse()
        for task in sortedDoLaterList:
            remainingTime = ((task.wakeTime) - self.currentTime)
            if task._removed:
                taskName = '(R)' + task.name
            else:
                taskName = task.name
            str += ('  ' + taskName.ljust(taskNameWidth-2)
                    +  dtfmt % (remainingTime)
                    + '\n')
        str += '-------------------------------------------------------------------------\n'
        str += "End of taskMgr info\n"
        return str

    def getTasks(self):
        # returns list of all tasks in arbitrary order
        tasks = []
        for taskPriList in self.taskList:
            for task in taskPriList:
                if task is not None and not task._removed:
                    tasks.append(task)
        for pri, taskList in self.pendingTaskDict.iteritems():
            for task in taskList:
                if not task._removed:
                    tasks.append(task)
        return tasks

    def getDoLaters(self):
        # returns list of all doLaters in arbitrary order
        return [doLater for doLater in self.__doLaterList
                if not doLater._removed]

    def resetStats(self):
        # WARNING: this screws up your do-later timings
        if self.taskTimerVerbose:
            for task in self.taskList:
                task.dt = 0
                task.avgDt = 0
                task.maxDt = 0
                task.runningTotal = 0
                task.setStartTimeFrame(self.currentTime, self.currentFrame)

    def popupControls(self):
        from direct.tkpanels import TaskManagerPanel
        return TaskManagerPanel.TaskManagerPanel(self)

    def __getTimeFrame(self):
        # WARNING: If you are testing tasks without an igLoop,
        # you must manually tick the clock
        # Ask for the time last frame
        if self.globalClock:
            return self.globalClock.getFrameTime(), self.globalClock.getFrameCount()
        # OK, we don't have a globalClock yet.  This is therefore
        # running before the first frame.
        return self.trueClock.getShortTime(), 0

    def __getTime(self):
        if self.globalClock:
            return self.globalClock.getFrameTime()
        return self.trueClock.getShortTime()

    if __debug__:
        # to catch memory leaks during the tests at the bottom of the file
        def _startTrackingMemLeaks(self):
            self._memUsage = ScratchPad()
            mu = self._memUsage
            mu.lenTaskList = len(self.taskList)
            mu.lenPendingTaskDict = len(self.pendingTaskDict)
            mu.lenDoLaterList = len(self.__doLaterList)
            mu.lenNameDict = len(self.nameDict)

        def _stopTrackingMemLeaks(self):
            self._memUsage.destroy()
            del self._memUsage

        def _checkMemLeaks(self):
            # flush removed doLaters
            self.__doLaterFilter()
            # give the mgr a chance to clear out removed tasks
            self.step()
            mu = self._memUsage
            # the task list looks like it grows and never shrinks, replacing finished
            # tasks with 'None' in the TaskPriorityLists.
            # TODO: look at reducing memory usage here--clear out excess at the end of every frame?
            #assert mu.lenTaskList == len(self.taskList)
            assert mu.lenPendingTaskDict == len(self.pendingTaskDict)
            assert mu.lenDoLaterList == len(self.__doLaterList)
            assert mu.lenNameDict == len(self.nameDict)

    def startOsd(self):
        self.add(self.doOsd, 'taskMgr.doOsd')
        self._osdEnabled = None
    def osdEnabled(self):
        return hasattr(self, '_osdEnabled')
    def stopOsd(self):
        onScreenDebug.removeAllWithPrefix(TaskManager.OsdPrefix)
        self.remove('taskMgr.doOsd')
        del self._osdEnabled
    def doOsd(self, task):
        if not onScreenDebug.enabled:
            return
        prefix = TaskManager.OsdPrefix
        onScreenDebug.removeAllWithPrefix(prefix)
        taskNameWidth = 32
        dtWidth = 10
        priorityWidth = 10
        totalDt = 0
        totalAvgDt = 0
        i = 0
        onScreenDebug.add(
            ('%s%02i.taskList' % (prefix, i)).ljust(taskNameWidth),
            '%s %s %s %s' % (
            'dt(ms)'.rjust(dtWidth),
            'avg'.rjust(dtWidth),
            'max'.rjust(dtWidth),
            'priority'.rjust(priorityWidth),))
        i += 1
        for taskPriList in self.taskList:
            priority = `taskPriList._priority`
            for task in taskPriList:
                if task is None:
                    break
                if task._removed:
                    taskName = '(R)' + task.name
                else:
                    taskName = task.name
                totalDt = totalDt + task.dt
                totalAvgDt = totalAvgDt + task.avgDt
                onScreenDebug.add(
                    ('%s%02i.%s' % (prefix, i, task.name)).ljust(taskNameWidth),
                    '%s %s %s %s' % (
                    dtfmt % (task.dt*1000),
                    dtfmt % (task.avgDt*1000),
                    dtfmt % (task.maxDt*1000),
                    priority.rjust(priorityWidth)))
                i += 1
        onScreenDebug.add(('%s%02i.total' % (prefix, i)).ljust(taskNameWidth),
                          '%s %s' % (
            dtfmt % (totalDt*1000),
            dtfmt % (totalAvgDt*1000),))
        return cont

    def _runTests(self):
        if __debug__:
            tm = TaskManager()
            # looks like nothing runs on the first frame...?
            # step to get past the first frame
            tm.step()

            # check for memory leaks after every test
            tm._startTrackingMemLeaks()
            tm._checkMemLeaks()

            # run-once task
            l = []
            def _testDone(task, l=l):
                l.append(None)
                return task.done
            tm.add(_testDone, 'testDone')
            tm.step()
            assert len(l) == 1
            tm.step()
            assert len(l) == 1
            _testDone = None
            tm._checkMemLeaks()

            # remove by name
            def _testRemoveByName(task):
                return task.done
            tm.add(_testRemoveByName, 'testRemoveByName')
            assert tm.remove('testRemoveByName') == 1
            assert tm.remove('testRemoveByName') == 0
            _testRemoveByName = None
            tm._checkMemLeaks()

            # duplicate named tasks
            def _testDupNamedTasks(task):
                return task.done
            tm.add(_testDupNamedTasks, 'testDupNamedTasks')
            tm.add(_testDupNamedTasks, 'testDupNamedTasks')
            assert tm.remove('testRemoveByName') == 0
            _testDupNamedTasks = None
            tm._checkMemLeaks()

            # continued task
            l = []
            def _testCont(task, l = l):
                l.append(None)
                return task.cont
            tm.add(_testCont, 'testCont')
            tm.step()
            assert len(l) == 1
            tm.step()
            assert len(l) == 2
            tm.remove('testCont')
            _testCont = None
            tm._checkMemLeaks()

            # continue until done task
            l = []
            def _testContDone(task, l = l):
                l.append(None)
                if len(l) >= 2:
                    return task.done
                else:
                    return task.cont
            tm.add(_testContDone, 'testContDone')
            tm.step()
            assert len(l) == 1
            tm.step()
            assert len(l) == 2
            tm.step()
            assert len(l) == 2
            assert not tm.hasTaskNamed('testContDone')
            _testContDone = None
            tm._checkMemLeaks()

            # hasTaskNamed
            def _testHasTaskNamed(task):
                return task.done
            tm.add(_testHasTaskNamed, 'testHasTaskNamed')
            assert tm.hasTaskNamed('testHasTaskNamed')
            tm.step()
            assert not tm.hasTaskNamed('testHasTaskNamed')
            _testHasTaskNamed = None
            tm._checkMemLeaks()

            # task priority
            l = []
            def _testPri1(task, l = l):
                l.append(1)
                return task.cont
            def _testPri2(task, l = l):
                l.append(2)
                return task.cont
            tm.add(_testPri1, 'testPri1', priority = 1)
            tm.add(_testPri2, 'testPri2', priority = 2)
            tm.step()
            assert len(l) == 2
            assert l == [1, 2,]
            tm.step()
            assert len(l) == 4
            assert l == [1, 2, 1, 2,]
            tm.remove('testPri1')
            tm.remove('testPri2')
            _testPri1 = None
            _testPri2 = None
            tm._checkMemLeaks()

            # task extraArgs
            l = []
            def _testExtraArgs(arg1, arg2, l=l):
                l.extend([arg1, arg2,])
                return done
            tm.add(_testExtraArgs, 'testExtraArgs', extraArgs=[4,5])
            tm.step()
            assert len(l) == 2
            assert l == [4, 5,]
            _testExtraArgs = None
            tm._checkMemLeaks()

            # task appendTask
            l = []
            def _testAppendTask(arg1, arg2, task, l=l):
                l.extend([arg1, arg2,])
                return task.done
            tm.add(_testAppendTask, '_testAppendTask', extraArgs=[4,5], appendTask=True)
            tm.step()
            assert len(l) == 2
            assert l == [4, 5,]
            _testAppendTask = None
            tm._checkMemLeaks()

            # task uponDeath
            l = []
            def _uponDeathFunc(task, l=l):
                l.append(task.name)
            def _testUponDeath(task):
                return done
            tm.add(_testUponDeath, 'testUponDeath', uponDeath=_uponDeathFunc)
            tm.step()
            assert len(l) == 1
            assert l == ['testUponDeath']
            _testUponDeath = None
            _uponDeathFunc = None
            tm._checkMemLeaks()

            # task owner
            class _TaskOwner:
                def _clearTask(self, task):
                    self.clearedTaskName = task.name
            to = _TaskOwner()
            l = []
            def _testOwner(task):
                return done
            tm.add(_testOwner, 'testOwner', owner=to)
            tm.step()
            assert hasattr(to, 'clearedTaskName')
            assert to.clearedTaskName == 'testOwner'
            _testOwner = None
            del to
            _TaskOwner = None
            tm._checkMemLeaks()


            doLaterTests = [0,]

            # doLater
            l = []
            def _testDoLater1(task, l=l):
                l.append(1)
            def _testDoLater2(task, l=l):
                l.append(2)
            def _monitorDoLater(task, tm=tm, l=l, doLaterTests=doLaterTests):
                if task.time > .03:
                    assert l == [1, 2,]
                    doLaterTests[0] -= 1
                    return task.done
                return task.cont
            tm.doMethodLater(.01, _testDoLater1, 'testDoLater1')
            tm.doMethodLater(.02, _testDoLater2, 'testDoLater2')
            doLaterTests[0] += 1
            # make sure we run this task after the doLaters if they all occur on the same frame
            tm.add(_monitorDoLater, 'monitorDoLater', priority=10)
            _testDoLater1 = None
            _testDoLater2 = None
            _monitorDoLater = None
            # don't check until all the doLaters are finished
            #tm._checkMemLeaks()

            # doLater priority
            l = []
            def _testDoLaterPri1(task, l=l):
                l.append(1)
            def _testDoLaterPri2(task, l=l):
                l.append(2)
            def _monitorDoLaterPri(task, tm=tm, l=l, doLaterTests=doLaterTests):
                if task.time > .02:
                    assert l == [1, 2,]
                    doLaterTests[0] -= 1
                    return task.done
                return task.cont
            tm.doMethodLater(.01, _testDoLaterPri1, 'testDoLaterPri1', priority=1)
            tm.doMethodLater(.01, _testDoLaterPri2, 'testDoLaterPri2', priority=2)
            doLaterTests[0] += 1
            # make sure we run this task after the doLaters if they all occur on the same frame
            tm.add(_monitorDoLaterPri, 'monitorDoLaterPri', priority=10)
            _testDoLaterPri1 = None
            _testDoLaterPri2 = None
            _monitorDoLaterPri = None
            # don't check until all the doLaters are finished
            #tm._checkMemLeaks()

            # doLater extraArgs
            l = []
            def _testDoLaterExtraArgs(arg1, l=l):
                l.append(arg1)
            def _monitorDoLaterExtraArgs(task, tm=tm, l=l, doLaterTests=doLaterTests):
                if task.time > .02:
                    assert l == [3,]
                    doLaterTests[0] -= 1
                    return task.done
                return task.cont
            tm.doMethodLater(.01, _testDoLaterExtraArgs, 'testDoLaterExtraArgs', extraArgs=[3,])
            doLaterTests[0] += 1
            # make sure we run this task after the doLaters if they all occur on the same frame
            tm.add(_monitorDoLaterExtraArgs, 'monitorDoLaterExtraArgs', priority=10)
            _testDoLaterExtraArgs = None
            _monitorDoLaterExtraArgs = None
            # don't check until all the doLaters are finished
            #tm._checkMemLeaks()

            # doLater appendTask
            l = []
            def _testDoLaterAppendTask(arg1, task, l=l):
                assert task.name == 'testDoLaterAppendTask'
                l.append(arg1)
            def _monitorDoLaterAppendTask(task, tm=tm, l=l, doLaterTests=doLaterTests):
                if task.time > .02:
                    assert l == [4,]
                    doLaterTests[0] -= 1
                    return task.done
                return task.cont
            tm.doMethodLater(.01, _testDoLaterAppendTask, 'testDoLaterAppendTask',
                             extraArgs=[4,], appendTask=True)
            doLaterTests[0] += 1
            # make sure we run this task after the doLaters if they all occur on the same frame
            tm.add(_monitorDoLaterAppendTask, 'monitorDoLaterAppendTask', priority=10)
            _testDoLaterAppendTask = None
            _monitorDoLaterAppendTask = None
            # don't check until all the doLaters are finished
            #tm._checkMemLeaks()

            # doLater uponDeath
            l = []
            def _testUponDeathFunc(task, l=l):
                assert task.name == 'testDoLaterUponDeath'
                l.append(10)
            def _testDoLaterUponDeath(arg1, l=l):
                return done
            def _monitorDoLaterUponDeath(task, tm=tm, l=l, doLaterTests=doLaterTests):
                if task.time > .02:
                    assert l == [10,]
                    doLaterTests[0] -= 1
                    return task.done
                return task.cont
            tm.doMethodLater(.01, _testDoLaterUponDeath, 'testDoLaterUponDeath',
                             uponDeath=_testUponDeathFunc)
            doLaterTests[0] += 1
            # make sure we run this task after the doLaters if they all occur on the same frame
            tm.add(_monitorDoLaterUponDeath, 'monitorDoLaterUponDeath', priority=10)
            _testUponDeathFunc = None
            _testDoLaterUponDeath = None
            _monitorDoLaterUponDeath = None
            # don't check until all the doLaters are finished
            #tm._checkMemLeaks()

            # doLater owner
            class _DoLaterOwner:
                def _clearTask(self, task):
                    self.clearedTaskName = task.name
            doLaterOwner = _DoLaterOwner()
            l = []
            def _testDoLaterOwner(l=l):
                pass
            def _monitorDoLaterOwner(task, tm=tm, l=l, doLaterOwner=doLaterOwner,
                                     doLaterTests=doLaterTests):
                if task.time > .02:
                    assert hasattr(doLaterOwner, 'clearedTaskName')
                    assert doLaterOwner.clearedTaskName == 'testDoLaterOwner'
                    doLaterTests[0] -= 1
                    return task.done
                return task.cont
            tm.doMethodLater(.01, _testDoLaterOwner, 'testDoLaterOwner',
                             owner=doLaterOwner)
            doLaterTests[0] += 1
            # make sure we run this task after the doLaters if they all occur on the same frame
            tm.add(_monitorDoLaterOwner, 'monitorDoLaterOwner', priority=10)
            _testDoLaterOwner = None
            _monitorDoLaterOwner = None
            del doLaterOwner
            _DoLaterOwner = None
            # don't check until all the doLaters are finished
            #tm._checkMemLeaks()

            # run the doLater tests
            while doLaterTests[0] > 0:
                tm.step()
            del doLaterTests
            tm._checkMemLeaks()

            # getTasks
            def _testGetTasks(task):
                return task.cont
            # the doLaterProcessor is always running
            assert len(tm.getTasks()) == 1
            tm.add(_testGetTasks, 'testGetTasks1')
            assert len(tm.getTasks()) == 2
            assert (tm.getTasks()[0].name == 'testGetTasks1' or
                    tm.getTasks()[1].name == 'testGetTasks1')
            tm.add(_testGetTasks, 'testGetTasks2')
            tm.add(_testGetTasks, 'testGetTasks3')
            assert len(tm.getTasks()) == 4
            tm.remove('testGetTasks2')
            assert len(tm.getTasks()) == 3
            tm.remove('testGetTasks1')
            tm.remove('testGetTasks3')
            assert len(tm.getTasks()) == 1
            _testGetTasks = None
            tm._checkMemLeaks()

            # getDoLaters
            def _testGetDoLaters():
                pass
            # the doLaterProcessor is always running
            assert len(tm.getDoLaters()) == 0
            tm.doMethodLater(.1, _testGetDoLaters, 'testDoLater1')
            assert len(tm.getDoLaters()) == 1
            assert tm.getDoLaters()[0].name == 'testDoLater1'
            tm.doMethodLater(.1, _testGetDoLaters, 'testDoLater2')
            tm.doMethodLater(.1, _testGetDoLaters, 'testDoLater3')
            assert len(tm.getDoLaters()) == 3
            tm.remove('testDoLater2')
            assert len(tm.getDoLaters()) == 2
            tm.remove('testDoLater1')
            tm.remove('testDoLater3')
            assert len(tm.getDoLaters()) == 0
            _testGetDoLaters = None
            tm._checkMemLeaks()

            # duplicate named doLaters removed via taskMgr.remove
            def _testDupNameDoLaters():
                pass
            # the doLaterProcessor is always running
            tm.doMethodLater(.1, _testDupNameDoLaters, 'testDupNameDoLater')
            tm.doMethodLater(.1, _testDupNameDoLaters, 'testDupNameDoLater')
            assert len(tm.getDoLaters()) == 2
            tm.remove('testDupNameDoLater')
            assert len(tm.getDoLaters()) == 0
            _testDupNameDoLaters = None
            tm._checkMemLeaks()

            # duplicate named doLaters removed via remove()
            def _testDupNameDoLatersRemove():
                pass
            # the doLaterProcessor is always running
            dl1 = tm.doMethodLater(.1, _testDupNameDoLatersRemove, 'testDupNameDoLaterRemove')
            dl2 = tm.doMethodLater(.1, _testDupNameDoLatersRemove, 'testDupNameDoLaterRemove')
            assert len(tm.getDoLaters()) == 2
            dl2.remove()
            assert len(tm.getDoLaters()) == 1
            dl1.remove()
            assert len(tm.getDoLaters()) == 0
            _testDupNameDoLatersRemove = None
            # nameDict etc. isn't cleared out right away with task.remove()
            tm._checkMemLeaks()

            # getTasksNamed
            def _testGetTasksNamed(task):
                return task.cont
            assert len(tm.getTasksNamed('testGetTasksNamed')) == 0
            tm.add(_testGetTasksNamed, 'testGetTasksNamed')
            assert len(tm.getTasksNamed('testGetTasksNamed')) == 1
            assert tm.getTasksNamed('testGetTasksNamed')[0].name == 'testGetTasksNamed'
            tm.add(_testGetTasksNamed, 'testGetTasksNamed')
            tm.add(_testGetTasksNamed, 'testGetTasksNamed')
            assert len(tm.getTasksNamed('testGetTasksNamed')) == 3
            tm.remove('testGetTasksNamed')
            assert len(tm.getTasksNamed('testGetTasksNamed')) == 0
            _testGetTasksNamed = None
            tm._checkMemLeaks()

            # removeTasksMatching
            def _testRemoveTasksMatching(task):
                return task.cont
            tm.add(_testRemoveTasksMatching, 'testRemoveTasksMatching')
            assert len(tm.getTasksNamed('testRemoveTasksMatching')) == 1
            tm.removeTasksMatching('testRemoveTasksMatching')
            assert len(tm.getTasksNamed('testRemoveTasksMatching')) == 0
            tm.add(_testRemoveTasksMatching, 'testRemoveTasksMatching1')
            tm.add(_testRemoveTasksMatching, 'testRemoveTasksMatching2')
            assert len(tm.getTasksNamed('testRemoveTasksMatching1')) == 1
            assert len(tm.getTasksNamed('testRemoveTasksMatching2')) == 1
            tm.removeTasksMatching('testRemoveTasksMatching*')
            assert len(tm.getTasksNamed('testRemoveTasksMatching1')) == 0
            assert len(tm.getTasksNamed('testRemoveTasksMatching2')) == 0
            tm.add(_testRemoveTasksMatching, 'testRemoveTasksMatching1a')
            tm.add(_testRemoveTasksMatching, 'testRemoveTasksMatching2a')
            assert len(tm.getTasksNamed('testRemoveTasksMatching1a')) == 1
            assert len(tm.getTasksNamed('testRemoveTasksMatching2a')) == 1
            tm.removeTasksMatching('testRemoveTasksMatching?a')
            assert len(tm.getTasksNamed('testRemoveTasksMatching1a')) == 0
            assert len(tm.getTasksNamed('testRemoveTasksMatching2a')) == 0
            _testRemoveTasksMatching = None
            tm._checkMemLeaks()

            # create Task object and add to mgr
            l = []
            def _testTaskObj(task, l=l):
                l.append(None)
                return task.cont
            t = Task(_testTaskObj)
            tm.add(t, 'testTaskObj')
            tm.step()
            assert len(l) == 1
            tm.step()
            assert len(l) == 2
            tm.remove('testTaskObj')
            tm.step()
            assert len(l) == 2
            _testTaskObj = None
            tm._checkMemLeaks()

            # remove Task via task.remove()
            l = []
            def _testTaskObjRemove(task, l=l):
                l.append(None)
                return task.cont
            t = Task(_testTaskObjRemove)
            tm.add(t, 'testTaskObjRemove')
            tm.step()
            assert len(l) == 1
            tm.step()
            assert len(l) == 2
            t.remove()
            tm.step()
            assert len(l) == 2
            del t
            _testTaskObjRemove = None
            tm._checkMemLeaks()

            """
            # this test fails, and it's not clear what the correct behavior should be.
            # priority passed to Task.__init__ is always overridden by taskMgr.add()
            # even if no priority is specified, and calling Task.setPriority() has no
            # effect on the taskMgr's behavior.
            # set/get Task priority
            l = []
            def _testTaskObjPriority(arg, task, l=l):
                l.append(arg)
                return task.cont
            t1 = Task(_testTaskObjPriority, priority=1)
            t2 = Task(_testTaskObjPriority, priority=2)
            tm.add(t1, 'testTaskObjPriority1', extraArgs=['a',], appendTask=True)
            tm.add(t2, 'testTaskObjPriority2', extraArgs=['b',], appendTask=True)
            tm.step()
            assert len(l) == 2
            assert l == ['a', 'b']
            assert t1.getPriority() == 1
            assert t2.getPriority() == 2
            t1.setPriority(3)
            assert t1.getPriority() == 3
            tm.step()
            assert len(l) == 4
            assert l == ['a', 'b', 'b', 'a',]
            t1.remove()
            t2.remove()
            tm.step()
            assert len(l) == 4
            del t1
            del t2
            _testTaskObjPriority = None
            tm._checkMemLeaks()
            """

            del l
            tm.destroy()
            del tm


# These constants are moved to the top level of the module,
# to make it easier for legacy code.  In general though, putting
# constants at the top level of a module is deprecated.

exit  = Task.exit
done  = Task.done
cont  = Task.cont
again = Task.again


if __debug__:
    pass # 'if __debug__' is hint for CVS diff output

"""

import Task

def goo(task):
    print 'goo'
    return Task.done

def bar(task):
    print 'bar'
    taskMgr.add(goo, 'goo')
    return Task.done

def foo(task):
    print 'foo'
    taskMgr.add(bar, 'bar')
    return Task.done

taskMgr.add(foo, 'foo')
"""