# MP-specific cache management
from pysnmp.proto.mpmod import cache

class AbstractMessageProcessingModel:
    def __init__(self):
        self._snmpMsgSpec = self.snmpMsgSpec()  # local copy
        self._cache = cache.Cache()
        
    def prepareOutgoingMessage(
        self,
        snmpEngine,
        transportDomain,
        transportAddress,
        messageProcessingModel,
        securityModel,
        securityName,
        securityLevel,
        contextEngineId,
        contextName,
        pduVersion,
        pdu,
        expectResponse,
        sendPduHandle
        ):
        raise error.ProtocolError('method not implemented')
        
    def prepareResponseMessage(
        self,
        snmpEngine,
        messageProcessingModel,
        securityModel,
        securityName,
        securityLevel,
        contextEngineId,
        contextName,
        pduVersion,
        pdu,
        maxSizeResponseScopedPDU,
        stateReference,
        statusInformation
        ):
        raise error.ProtocolError('method not implemented')

    def prepareDataElements(
        self,
        snmpEngine,
        transportDomain,
        transportAddress,
        wholeMsg
        ):
        raise error.ProtocolError('method not implemented')

    def releaseStateInformation(self, sendPduHandle):
        try:
            self._cache.popBySendPduHandle(sendPduHandle)
        except error.ProtocolError:
            pass # XXX maybe these should all follow some scheme?
    
    def receiveTimerTick(self, snmpEngine, timeNow):
        self._cache.expireCaches()
