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#
# This file is part of pysnmp software.
#
# Copyright (c) 2005-2019, Ilya Etingof <etingof@gmail.com>
# License: http://snmplabs.com/pysnmp/license.html
#
from pysnmp import nextid
from pysnmp.proto import error
class Cache(object):
__stateReference = nextid.Integer(0xffffff)
__msgID = nextid.Integer(0xffffff)
def __init__(self):
self.__msgIdIndex = {}
self.__stateReferenceIndex = {}
self.__sendPduHandleIdx = {}
# Message expiration mechanics
self.__expirationQueue = {}
self.__expirationTimer = 0
# Server mode cache handling
def newStateReference(self):
return self.__stateReference()
def pushByStateRef(self, stateReference, **msgInfo):
if stateReference in self.__stateReferenceIndex:
raise error.ProtocolError(
'Cache dup for stateReference=%s at %s' % (stateReference, self))
expireAt = self.__expirationTimer + 600
self.__stateReferenceIndex[stateReference] = msgInfo, expireAt
# Schedule to expire
if expireAt not in self.__expirationQueue:
self.__expirationQueue[expireAt] = {}
if 'stateReference' not in self.__expirationQueue[expireAt]:
self.__expirationQueue[expireAt]['stateReference'] = {}
self.__expirationQueue[expireAt]['stateReference'][stateReference] = 1
def popByStateRef(self, stateReference):
if stateReference in self.__stateReferenceIndex:
cacheInfo = self.__stateReferenceIndex[stateReference]
else:
raise error.ProtocolError(
'Cache miss for stateReference=%s at '
'%s' % (stateReference, self))
del self.__stateReferenceIndex[stateReference]
cacheEntry, expireAt = cacheInfo
del self.__expirationQueue[expireAt]['stateReference'][stateReference]
return cacheEntry
# Client mode cache handling
def newMsgID(self):
return self.__msgID()
def pushByMsgId(self, msgId, **msgInfo):
if msgId in self.__msgIdIndex:
raise error.ProtocolError(
'Cache dup for msgId=%s at %s' % (msgId, self))
expireAt = self.__expirationTimer + 600
self.__msgIdIndex[msgId] = msgInfo, expireAt
self.__sendPduHandleIdx[msgInfo['sendPduHandle']] = msgId
# Schedule to expire
if expireAt not in self.__expirationQueue:
self.__expirationQueue[expireAt] = {}
if 'msgId' not in self.__expirationQueue[expireAt]:
self.__expirationQueue[expireAt]['msgId'] = {}
self.__expirationQueue[expireAt]['msgId'][msgId] = 1
def popByMsgId(self, msgId):
if msgId in self.__msgIdIndex:
cacheInfo = self.__msgIdIndex[msgId]
else:
raise error.ProtocolError(
'Cache miss for msgId=%s at %s' % (msgId, self))
msgInfo, expireAt = cacheInfo
del self.__sendPduHandleIdx[msgInfo['sendPduHandle']]
del self.__msgIdIndex[msgId]
cacheEntry, expireAt = cacheInfo
del self.__expirationQueue[expireAt]['msgId'][msgId]
return cacheEntry
def popBySendPduHandle(self, sendPduHandle):
if sendPduHandle in self.__sendPduHandleIdx:
self.popByMsgId(self.__sendPduHandleIdx[sendPduHandle])
def expireCaches(self):
# Uses internal clock to expire pending messages
if self.__expirationTimer in self.__expirationQueue:
cacheInfo = self.__expirationQueue[self.__expirationTimer]
if 'stateReference' in cacheInfo:
for stateReference in cacheInfo['stateReference']:
del self.__stateReferenceIndex[stateReference]
if 'msgId' in cacheInfo:
for msgId in cacheInfo['msgId']:
del self.__msgIdIndex[msgId]
del self.__expirationQueue[self.__expirationTimer]
self.__expirationTimer += 1
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