panda3d/direct/src/distributed/ClientRepository.py

"""ClientRepository module: contains the ClientRepository class"""

from pandac.PandaModules import *
from MsgTypes import *
from direct.task import Task
from direct.directnotify import DirectNotifyGlobal
import CRCache
from direct.distributed.ConnectionRepository import ConnectionRepository
from direct.showbase import PythonUtil
import ParentMgr
import RelatedObjectMgr
import time
from ClockDelta import *
from PyDatagram import PyDatagram
from PyDatagramIterator import PyDatagramIterator

class ClientRepository(ConnectionRepository):
    """
    This maintains a client-side connection with a Panda server.
    It currently supports several different versions of the server:
    within the VR Studio, we are currently in transition from the
    Toontown server to the OTP server; people outside the VR studio
    will use the Panda LAN server provided by CMU.
    """
    notify = DirectNotifyGlobal.directNotify.newCategory("ClientRepository")

    def __init__(self, dcFileNames = None):
        self.dcSuffix=""
        ConnectionRepository.__init__(self, base.config, hasOwnerView=True)

        self.context=100000
        self.setClientDatagram(1)

        self.recorder = base.recorder

        self.readDCFile(dcFileNames)
        self.cache=CRCache.CRCache()
        self.cacheOwner=CRCache.CRCache()
        self.serverDelta = 0

        self.bootedIndex = None
        self.bootedText = None

        if 0: # unused:
            self.worldScale = render.attachNewNode("worldScale") # for grid zones.
            self.worldScale.setScale(base.config.GetFloat('world-scale', 100))
            self.priorWorldPos = None

        # create a parentMgr to handle distributed reparents
        # this used to be 'token2nodePath'
        self.parentMgr = ParentMgr.ParentMgr()

        # The RelatedObjectMgr helps distributed objects find each
        # other.
        self.relatedObjectMgr = RelatedObjectMgr.RelatedObjectMgr(self)

        # Keep track of how recently we last sent a heartbeat message.
        # We want to keep these coming at heartbeatInterval seconds.
        self.heartbeatInterval = base.config.GetDouble('heartbeat-interval', 10)
        self.heartbeatStarted = 0
        self.lastHeartbeat = 0

        # By default, the ClientRepository is set up to respond to
        # datagrams from the CMU Panda LAN server.  You can
        # reassign this member to change the response behavior
        # according to game context.
        self.handler = self.publicServerDatagramHandler

        # The DOID allocator.  The CMU LAN server may choose to
        # send us a block of DOIDs.  If it chooses to do so, then we
        # may create objects, using those DOIDs.  These structures are
        # only used in conjunction with the CMU LAN server.
        self.DOIDbase = 0
        self.DOIDnext = 0
        self.DOIDlast = 0

    ## def queryObjectAll(self, doID, context=0):
        ## """
        ## Get a one-time snapshot look at the object.
        ## """
        ## assert self.notify.debugStateCall(self)
        ## # Create a message
        ## datagram = PyDatagram()
        ## datagram.addServerHeader(
            ## doID, localAvatar.getDoId(), 2020)           
        ## # A context that can be used to index the response if needed
        ## datagram.addUint32(context)
        ## self.send(datagram)
        ## # Make sure the message gets there.
        ## self.flush()

    # Define uniqueName
    def uniqueName(self, desc):
        return desc

    def getTables(self, ownerView):
        if ownerView:
            return self.doId2ownerView, self.cacheOwner
        else:
            return self.doId2do, self.cache

    def abruptCleanup(self):
        """
        Call this method to clean up any pending hooks or tasks on
        distributed objects, but leave the ClientRepository in a sane
        state for creating more distributed objects.
        """
        self.relatedObjectMgr.abortAllRequests()

    def sendDisconnect(self):
        if self.isConnected():
            # Tell the game server that we're going:
            datagram = PyDatagram()
            # Add message type
            datagram.addUint16(CLIENT_DISCONNECT)
            # Send the message
            self.send(datagram)
            self.notify.info("Sent disconnect message to server")
            self.disconnect()
        self.stopHeartbeat()

    if 0: # Code that became obsolete before it was used:
        def setWorldOffset(self, xOffset=0, yOffset=0):
            self.worldXOffset=xOffset
            self.worldYOffset=yOffset

        def getWorldPos(self, nodePath):
            pos = nodePath.getPos(self.worldScale)
            return (int(round(pos.getX())), int(round(pos.getY())))

        def sendWorldPos(self, x, y):
            # The server will need to know the world
            # offset of our current render node path
            # and adjust the x, y accordingly.  At one
            # point I considered adding the world offset
            # here, but that would just use extra bits.

            onScreenDebug.add("worldPos", "%-4d, %-4d"%(x, y))
            return #*#

            datagram = PyDatagram()
            # Add message type
            datagram.addUint16(CLIENT_SET_WORLD_POS)
            # Add x
            datagram.addInt16(x)
            # Add y
            datagram.addSint16(y)
            # send the message
            self.send(datagram)

        def checkWorldPos(self, nodePath):
            worldPos = self.getWorldPos(nodePath)
            if self.priorWorldPos != worldPos:
                self.priorWorldPos = worldPos
                self.sendWorldPos(worldPos[0], worldPos[1])

    def allocateContext(self):
        self.context+=1
        return self.context

    def setServerDelta(self, delta):
        """
        Indicates the approximate difference in seconds between the
        client's clock and the server's clock, in universal time (not
        including timezone shifts).  This is mainly useful for
        reporting synchronization information to the logs; don't
        depend on it for any precise timing requirements.

        Also see Notify.setServerDelta(), which also accounts for a
        timezone shift.
        """
        self.serverDelta = delta

    def getServerDelta(self):
        return self.serverDelta

    def getServerTimeOfDay(self):
        """
        Returns the current time of day (seconds elapsed since the
        1972 epoch) according to the server's clock.  This is in GMT,
        and hence is irrespective of timezones.

        The value is computed based on the client's clock and the
        known delta from the server's clock, which is not terribly
        precisely measured and may drift slightly after startup, but
        it should be accurate plus or minus a couple of seconds.
        """
        return time.time() + self.serverDelta

    def handleGenerateWithRequired(self, di):
        parentId = di.getUint32()
        zoneId = di.getUint32()
        assert parentId == self.GameGlobalsId or parentId in self.doId2do
        # Get the class Id
        classId = di.getUint16()
        # Get the DO Id
        doId = di.getUint32()
        # Look up the dclass
        dclass = self.dclassesByNumber[classId]
        dclass.startGenerate()
        # Create a new distributed object, and put it in the dictionary
        distObj = self.generateWithRequiredFields(dclass, doId, di, parentId, zoneId)
        dclass.stopGenerate()

    def handleGenerateWithRequiredOther(self, di):
        parentId = di.getUint32()
        zoneId = di.getUint32()
        assert parentId == self.GameGlobalsId or parentId in self.doId2do
        # Get the class Id
        classId = di.getUint16()
        # Get the DO Id
        doId = di.getUint32()
        # Look up the dclass
        dclass = self.dclassesByNumber[classId]
        dclass.startGenerate()
        # Create a new distributed object, and put it in the dictionary
        distObj = self.generateWithRequiredOtherFields(dclass, doId, di, parentId, zoneId)
        dclass.stopGenerate()

    def handleGenerateWithRequiredOtherOwner(self, di):
        # Get the class Id
        classId = di.getUint16()
        # Get the DO Id
        doId = di.getUint32()
        # parentId and zoneId are not relevant here
        parentId = di.getUint32()
        zoneId = di.getUint32()
        # Look up the dclass
        dclass = self.dclassesByNumber[classId]
        dclass.startGenerate()
        # Create a new distributed object, and put it in the dictionary
        distObj = self.generateWithRequiredOtherFieldsOwner(dclass, doId, di)
        dclass.stopGenerate()

    def handleQuietZoneGenerateWithRequired(self, di):
        # Special handler for quiet zone generates -- we need to filter
        parentId = di.getUint32()
        zoneId = di.getUint32()
        assert parentId in self.doId2do
        # Get the class Id
        classId = di.getUint16()
        # Get the DO Id
        doId = di.getUint32()
        # Look up the dclass
        dclass = self.dclassesByNumber[classId]
        dclass.startGenerate()
        distObj = self.generateWithRequiredFields(dclass, doId, di, parentId, zoneId)
        dclass.stopGenerate()

    def handleQuietZoneGenerateWithRequiredOther(self, di):
        # Special handler for quiet zone generates -- we need to filter
        parentId = di.getUint32()
        zoneId = di.getUint32()
        assert parentId in self.doId2do
        # Get the class Id
        classId = di.getUint16()
        # Get the DO Id
        doId = di.getUint32()
        # Look up the dclass
        dclass = self.dclassesByNumber[classId]
        dclass.startGenerate()
        distObj = self.generateWithRequiredOtherFields(dclass, doId, di, parentId, zoneId)
        dclass.stopGenerate()

    def generateWithRequiredFields(self, dclass, doId, di, parentId, zoneId):
        if self.doId2do.has_key(doId):
            # ...it is in our dictionary.
            # Just update it.
            distObj = self.doId2do[doId]
            assert(distObj.dclass == dclass)
            distObj.generate()
            distObj.setLocation(parentId, zoneId)
            distObj.updateRequiredFields(dclass, di)
            # updateRequiredFields calls announceGenerate
        elif self.cache.contains(doId):
            # ...it is in the cache.
            # Pull it out of the cache:
            distObj = self.cache.retrieve(doId)
            assert(distObj.dclass == dclass)
            # put it in the dictionary:
            self.doId2do[doId] = distObj
            # and update it.
            distObj.generate()
            distObj.setLocation(parentId, zoneId)
            distObj.updateRequiredFields(dclass, di)
            # updateRequiredFields calls announceGenerate
        else:
            # ...it is not in the dictionary or the cache.
            # Construct a new one
            classDef = dclass.getClassDef()
            if classDef == None:
                self.notify.error("Could not create an undefined %s object." % (dclass.getName()))
            distObj = classDef(self)
            distObj.dclass = dclass
            # Assign it an Id
            distObj.doId = doId
            # Put the new do in the dictionary
            self.doId2do[doId] = distObj
            # Update the required fields
            distObj.generateInit()  # Only called when constructed
            distObj.generate()
            distObj.setLocation(parentId, zoneId)
            distObj.updateRequiredFields(dclass, di)
            # updateRequiredFields calls announceGenerate
            print "New DO:%s, dclass:%s"%(doId, dclass.getName())
        return distObj

    ## def generateGlobalObject(self, doId, dcname):
        ## # Look up the dclass
        ## dclass = self.dclassesByName[dcname]
        ## # Create a new distributed object, and put it in the dictionary
        ## #distObj = self.generateWithRequiredFields(dclass, doId, di)

        ## # Construct a new one
        ## classDef = dclass.getClassDef()
        ## if classDef == None:
             ## self.notify.error("Could not create an undefined %s object."%(
                ## dclass.getName()))
        ## distObj = classDef(self)
        ## distObj.dclass = dclass
        ## # Assign it an Id
        ## distObj.doId = doId
        ## # Put the new do in the dictionary
        ## self.doId2do[doId] = distObj
        ## # Update the required fields
        ## distObj.generateInit()  # Only called when constructed
        ## distObj.generate()
        ## # TODO: ROGER: where should we get parentId and zoneId?
        ## parentId = None
        ## zoneId = None
        ## distObj.setLocation(parentId, zoneId)
        ## # updateRequiredFields calls announceGenerate
        ## return  distObj

    def generateWithRequiredOtherFields(self, dclass, doId, di,
                                        parentId = None, zoneId = None):
        if self.doId2do.has_key(doId):
            # ...it is in our dictionary.
            # Just update it.
            distObj = self.doId2do[doId]
            assert(distObj.dclass == dclass)
            distObj.generate()
            distObj.setLocation(parentId, zoneId)
            distObj.updateRequiredOtherFields(dclass, di)
            # updateRequiredOtherFields calls announceGenerate
        elif self.cache.contains(doId):
            # ...it is in the cache.
            # Pull it out of the cache:
            distObj = self.cache.retrieve(doId)
            assert(distObj.dclass == dclass)
            # put it in the dictionary:
            self.doId2do[doId] = distObj
            # and update it.
            distObj.generate()
            distObj.setLocation(parentId, zoneId)
            distObj.updateRequiredOtherFields(dclass, di)
            # updateRequiredOtherFields calls announceGenerate
        else:
            # ...it is not in the dictionary or the cache.
            # Construct a new one
            classDef = dclass.getClassDef()
            if classDef == None:
                self.notify.error("Could not create an undefined %s object." % (dclass.getName()))
            distObj = classDef(self)
            distObj.dclass = dclass
            # Assign it an Id
            distObj.doId = doId
            # Put the new do in the dictionary
            self.doId2do[doId] = distObj
            # Update the required fields
            distObj.generateInit()  # Only called when constructed
            distObj.generate()
            distObj.setLocation(parentId, zoneId)
            distObj.updateRequiredOtherFields(dclass, di)
            # updateRequiredOtherFields calls announceGenerate
        return distObj

    def generateWithRequiredOtherFieldsOwner(self, dclass, doId, di):
        if self.doId2ownerView.has_key(doId):
            # ...it is in our dictionary.
            # Just update it.
            distObj = self.doId2ownerView[doId]
            assert(distObj.dclass == dclass)
            distObj.generate()
            distObj.updateRequiredOtherFields(dclass, di)
            # updateRequiredOtherFields calls announceGenerate
        elif self.cacheOwner.contains(doId):
            # ...it is in the cache.
            # Pull it out of the cache:
            distObj = self.cacheOwner.retrieve(doId)
            assert(distObj.dclass == dclass)
            # put it in the dictionary:
            self.doId2ownerView[doId] = distObj
            # and update it.
            distObj.generate()
            distObj.updateRequiredOtherFields(dclass, di)
            # updateRequiredOtherFields calls announceGenerate
        else:
            # ...it is not in the dictionary or the cache.
            # Construct a new one
            classDef = dclass.getOwnerClassDef()
            if classDef == None:
                self.notify.error("Could not create an undefined %s object. Have you created an owner view?" % (dclass.getName()))
            distObj = classDef(self)
            distObj.dclass = dclass
            # Assign it an Id
            distObj.doId = doId
            # Put the new do in the dictionary
            self.doId2ownerView[doId] = distObj
            # Update the required fields
            distObj.generateInit()  # Only called when constructed
            distObj.generate()
            distObj.updateRequiredOtherFields(dclass, di)
            # updateRequiredOtherFields calls announceGenerate
        return distObj


    def handleDisable(self, di, ownerView=False):
        # Get the DO Id
        doId = di.getUint32()
        # disable it.
        self.disableDoId(doId, ownerView)

    def disableDoId(self, doId, ownerView=False):
        table, cache = self.getTables(ownerView)
        # Make sure the object exists
        if table.has_key(doId):
            # Look up the object
            distObj = table[doId]
            # remove the object from the dictionary
            del table[doId]

            # Only cache the object if it is a "cacheable" type
            # object; this way we don't clutter up the caches with
            # trivial objects that don't benefit from caching.
            if distObj.getCacheable():
                cache.cache(distObj)
            else:
                distObj.deleteOrDelay()
        else:
            ClientRepository.notify.warning(
                "Disable failed. DistObj "
                + str(doId) +
                " is not in dictionary, ownerView=%s" % ownerView)

    def handleDelete(self, di):
        # overridden by ToontownClientRepository
        assert 0

    def handleUpdateField(self, di):
        """
        This method is called when a CLIENT_OBJECT_UPDATE_FIELD
        message is received; it decodes the update, unpacks the
        arguments, and calls the corresponding method on the indicated
        DistributedObject.

        In fact, this method is exactly duplicated by the C++ method
        cConnectionRepository::handle_update_field(), which was
        written to optimize the message loop by handling all of the
        CLIENT_OBJECT_UPDATE_FIELD messages in C++.  That means that
        nowadays, this Python method will probably never be called,
        since UPDATE_FIELD messages will not even be passed to the
        Python message handlers.  But this method remains for
        documentation purposes, and also as a "just in case" handler
        in case we ever do come across a situation in the future in
        which python might handle the UPDATE_FIELD message.
        """
        # Get the DO Id
        doId = di.getUint32()
        #print("Updating " + str(doId))
        # Find the DO

        do = self.doId2do.get(doId)
        if do is not None:
            # Let the dclass finish the job
            do.dclass.receiveUpdate(do, di)
        else:
            ClientRepository.notify.warning(
                "Asked to update non-existent DistObj " + str(doId))

    def handleGoGetLost(self, di):
        # The server told us it's about to drop the connection on us.
        # Get ready!
        if (di.getRemainingSize() > 0):
            self.bootedIndex = di.getUint16()
            self.bootedText = di.getString()

            ClientRepository.notify.warning(
                "Server is booting us out (%d): %s" % (self.bootedIndex, self.bootedText))
        else:
            self.bootedIndex = None
            self.bootedText = None
            ClientRepository.notify.warning(
                "Server is booting us out with no explanation.")

    def handleServerHeartbeat(self, di):
        # Got a heartbeat message from the server.
        if base.config.GetBool('server-heartbeat-info', 1):
            ClientRepository.notify.info("Server heartbeat.")

    def handleSystemMessage(self, di):
        # Got a system message from the server.
        message = di.getString()
        self.notify.info('Message from server: %s' % (message))
        return message

    def handleSetDOIDrange(self, di):
        # This method is only used in conjunction with the CMU LAN
        # server.

        self.DOIDbase = di.getUint32()
        self.DOIDlast = self.DOIDbase + di.getUint32()
        self.DOIDnext = self.DOIDbase

    def handleRequestGenerates(self, di):
        # When new clients join the zone of an object, they need to hear
        # about it, so we send out all of our information about objects in
        # that particular zone.

        # This method is only used in conjunction with the CMU LAN
        # server.

        assert self.DOIDnext < self.DOIDlast
        zone = di.getUint32()
        for obj in self.doId2do.values():
            if obj.zone == zone:
                id = obj.doId
                if (self.isLocalId(id)):
                    self.send(obj.dclass.clientFormatGenerate(obj, id, zone, []))

    def handleMessageType(self, msgType, di):
        if msgType == CLIENT_GO_GET_LOST:
            self.handleGoGetLost(di)
        elif msgType == CLIENT_HEARTBEAT:
            self.handleServerHeartbeat(di)
        elif msgType == CLIENT_SYSTEM_MESSAGE:
            self.handleSystemMessage(di)
        elif msgType == CLIENT_CREATE_OBJECT_REQUIRED:
            self.handleGenerateWithRequired(di)
        elif msgType == CLIENT_CREATE_OBJECT_REQUIRED_OTHER:
            self.handleGenerateWithRequiredOther(di)
        elif msgType == CLIENT_CREATE_OBJECT_REQUIRED_OTHER_OWNER:
            self.handleGenerateWithRequiredOtherOwner(di)
        elif msgType == CLIENT_OBJECT_UPDATE_FIELD:
            self.handleUpdateField(di)
        elif msgType == CLIENT_OBJECT_DISABLE:
            self.handleDisable(di)
        elif msgType == CLIENT_OBJECT_DISABLE_OWNER:
            self.handleDisable(di, ownerView=True)
        elif msgType == CLIENT_OBJECT_DELETE_RESP:
            self.handleDelete(di)
        elif msgType == CLIENT_DONE_INTEREST_RESP:
            self.handleInterestDoneMessage(di)
        #Roger wants to remove this elif msgType == CLIENT_QUERY_ONE_FIELD_RESP:
        #Roger wants to remove this     self.handleQueryOneFieldResp(di)
        elif msgType == CLIENT_OBJECT_LOCATION:
            self.handleObjectLocation(di)
        else:
            currentLoginState = self.loginFSM.getCurrentState()
            if currentLoginState:
                currentLoginStateName = currentLoginState.getName()
            else:
                currentLoginStateName = "None"
            currentGameState = self.gameFSM.getCurrentState()
            if currentGameState:
                currentGameStateName = currentGameState.getName()
            else:
                currentGameStateName = "None"
            ClientRepository.notify.warning(
                "Ignoring unexpected message type: " +
                str(msgType) +
                " login state: " +
                currentLoginStateName +
                " game state: " +
                currentGameStateName)
                    
    def createWithRequired(self, className, zoneId = 0, optionalFields=None):
        # This method is only used in conjunction with the CMU LAN
        # server.

        if self.DOIDnext >= self.DOIDlast:
            self.notify.error(
                "Cannot allocate a distributed object ID: all IDs used up.")
            return None
        id = self.DOIDnext
        self.DOIDnext = self.DOIDnext + 1
        dclass = self.dclassesByName[className]
        classDef = dclass.getClassDef()
        if classDef == None:
            self.notify.error("Could not create an undefined %s object." % (
                dclass.getName()))
        obj = classDef(self)
        obj.dclass = dclass
        obj.zone = zoneId
        obj.doId = id
        self.doId2do[id] = obj
        obj.generateInit()
        obj.generate()
        obj.announceGenerate()
        datagram = dclass.clientFormatGenerate(obj, id, zoneId, optionalFields)
        self.send(datagram)
        return obj

    def sendDisableMsg(self, doId):
        # This method is only used in conjunction with the CMU LAN
        # server.

        datagram = PyDatagram()
        datagram.addUint16(CLIENT_OBJECT_DISABLE)
        datagram.addUint32(doId)
        self.send(datagram)

    def sendDeleteMsg(self, doId):
        # This method is only used in conjunction with the CMU LAN
        # server.

        datagram = PyDatagram()
        datagram.addUint16(CLIENT_OBJECT_DELETE)
        datagram.addUint32(doId)
        self.send(datagram)

    def sendRemoveZoneMsg(self, zoneId, visibleZoneList=None):
        # This method is only used in conjunction with the CMU LAN
        # server.

        datagram = PyDatagram()
        datagram.addUint16(CLIENT_REMOVE_ZONE)
        datagram.addUint32(zoneId)

        # if we have an explicit list of visible zones, add them
        if visibleZoneList is not None:
            vzl = list(visibleZoneList)
            vzl.sort()
            assert PythonUtil.uniqueElements(vzl)
            for zone in vzl:
                datagram.addUint32(zone)

        # send the message
        self.send(datagram)

    def getObjectsOfClass(self, objClass):
        """ returns dict of doId:object, containing all objects
        that inherit from 'class'. returned dict is safely mutable. """
        doDict = {}
        for doId, do in self.doId2do.items():
            if isinstance(do, objClass):
                doDict[doId] = do
        return doDict

    def getObjectsOfExactClass(self, objClass):
        """ returns dict of doId:object, containing all objects that
        are exactly of type 'class' (neglecting inheritance). returned
        dict is safely mutable. """
        doDict = {}
        for doId, do in self.doId2do.items():
            if do.__class__ == objClass:
                doDict[doId] = do
        return doDict


    def sendSetLocation(self,doId,parentId,zoneId):
        datagram = PyDatagram()
        datagram.addUint16(CLIENT_OBJECT_LOCATION)
        datagram.addUint32(doId)
        datagram.addUint32(parentId)
        datagram.addUint32(zoneId)
        self.send(datagram)

    def handleDatagram(self, di):
        if self.notify.getDebug():
            print "ClientRepository received datagram:"
            di.getDatagram().dumpHex(ostream)


        msgType = self.getMsgType()

        if self.handler == None:
            self.handleMessageType(msgType, di)
        else:
            self.handler(msgType, di)

        # If we're processing a lot of datagrams within one frame, we
        # may forget to send heartbeats.  Keep them coming!
        self.considerHeartbeat()

    def publicServerDatagramHandler(self, msgType, di):

        # These are the sort of messages we may expect from the public
        # Panda server.

        if msgType == CLIENT_SET_DOID_RANGE:
            self.handleSetDOIDrange(di)
        elif msgType == CLIENT_CREATE_OBJECT_REQUIRED_RESP:
            self.handleGenerateWithRequired(di)
        elif msgType == CLIENT_CREATE_OBJECT_REQUIRED_OTHER_RESP:
            self.handleGenerateWithRequiredOther(di)
        elif msgType == CLIENT_OBJECT_UPDATE_FIELD_RESP:
            self.handleUpdateField(di)
        elif msgType == CLIENT_OBJECT_DELETE_RESP:
            self.handleDelete(di)
        elif msgType == CLIENT_OBJECT_DISABLE_RESP:
            self.handleDisable(di)
        elif msgType == CLIENT_REQUEST_GENERATES:
            self.handleRequestGenerates(di)
        else:
            self.handleMessageType(msgType, di)

    def sendHeartbeat(self):
        datagram = PyDatagram()
        # Add message type
        datagram.addUint16(CLIENT_HEARTBEAT)
        # Send it!
        self.send(datagram)
        self.lastHeartbeat = globalClock.getRealTime()
        # This is important enough to consider flushing immediately
        # (particularly if we haven't run readerPollTask recently).
        self.considerFlush()

    def considerHeartbeat(self):
        """Send a heartbeat message if we haven't sent one recently."""
        if not self.heartbeatStarted:
            self.notify.debug("Heartbeats not started; not sending.")
            return

        elapsed = globalClock.getRealTime() - self.lastHeartbeat
        if elapsed < 0 or elapsed > self.heartbeatInterval:
            # It's time to send the heartbeat again (or maybe someone
            # reset the clock back).
            self.notify.info("Sending heartbeat mid-frame.")
            self.startHeartbeat()

    def stopHeartbeat(self):
        taskMgr.remove("heartBeat")
        self.heartbeatStarted = 0

    def startHeartbeat(self):
        self.stopHeartbeat()
        self.heartbeatStarted = 1
        self.sendHeartbeat()
        self.waitForNextHeartBeat()

    def sendHeartbeatTask(self, task):
        self.sendHeartbeat()
        self.waitForNextHeartBeat()
        return Task.done

    def waitForNextHeartBeat(self):
        taskMgr.doMethodLater(self.heartbeatInterval, self.sendHeartbeatTask,
                              "heartBeat")

    def sendUpdateZone(self, obj, zoneId):
        # This method is only used in conjunction with the CMU LAN
        # server.

        id = obj.doId
        assert(self.isLocalId(id))
        self.sendDeleteMsg(id, 1)
        obj.zone = zoneId
        self.send(obj.dclass.clientFormatGenerate(obj, id, zoneId, []))

    def replaceMethod(self, oldMethod, newFunction):
        return 0

    def isLocalId(self,id):
        return ((id >= self.DOIDbase) and (id < self.DOIDlast))

    def haveCreateAuthority(self):
        return (self.DOIDlast > self.DOIDnext)

    def getWorld(self, doId):
        # Get the world node for this object
        obj = self.doId2do[doId]

        worldNP = obj.getParent()
        while 1:
            nextNP = worldNP.getParent()
            if nextNP == render:
                break
            elif worldNP.isEmpty():
                return None
        return worldNP