internal cache split off security modules to facilitate code reuse

4 files changed, 32 insertions, 28 deletions

diff --git a/pysnmp/proto/secmod/base.py b/pysnmp/proto/secmod/base.py
index 70ca456..d4daaac 100644
--- a/pysnmp/proto/secmod/base.py
+++ b/pysnmp/proto/secmod/base.py
@@ -1,10 +1,10 @@
+from pysnmp.proto.secmod import cache
 from pysnmp.proto import error
 
 class AbstractSecurityModel:
     securityModelID = None
-    __stateReference = 0L
     def __init__(self):
-        self.__cacheEntries = {}
+        self._cache = cache.Cache()
 
     def processIncomingMsg(
         self,
@@ -54,27 +54,8 @@ class AbstractSecurityModel:
             'Security model %s not implemented' % self
             )
 
-    # Caching stuff
-    
-    def _cachePush(self, **securityData):
-        stateReference = AbstractSecurityModel.__stateReference
-        AbstractSecurityModel.__stateReference = stateReference + 1
-        self.__cacheEntries[stateReference] = securityData
-        return stateReference
-    
-    def _cachePop(self, stateReference):
-        if stateReference in self.__cacheEntries:
-            securityData = self.__cacheEntries[stateReference]
-        else:
-            raise error.ProtocolError(
-                'Cache miss for stateReference=%s at %s' %
-                (stateReference, self)
-                )
-        del self.__cacheEntries[stateReference]
-        return securityData
-
     def releaseStateInformation(self, stateReference):
-        self._cachePop(stateReference)
+        self._cache.pop(stateReference)
 
     def receiveTimerTick(self, snmpEngine, timeNow):
         pass
diff --git a/pysnmp/proto/secmod/cache.py b/pysnmp/proto/secmod/cache.py
new file mode 100644
index 0000000..89e45ca
--- /dev/null
+++ b/pysnmp/proto/secmod/cache.py
@@ -0,0 +1,23 @@
+from pysnmp import nextid
+from pysnmp.proto import error
+
+class Cache:
+    __stateReference = nextid.Integer(0xffffff)
+    def __init__(self):
+        self.__cacheEntries = {}
+
+    def push(self, **securityData):
+        stateReference = self.__stateReference()
+        self.__cacheEntries[stateReference] = securityData
+        return stateReference
+    
+    def pop(self, stateReference):
+        if stateReference in self.__cacheEntries:
+            securityData = self.__cacheEntries[stateReference]
+        else:
+            raise error.ProtocolError(
+                'Cache miss for stateReference=%s at %s' %
+                (stateReference, self)
+                )
+        del self.__cacheEntries[stateReference]
+        return securityData
diff --git a/pysnmp/proto/secmod/rfc2576.py b/pysnmp/proto/secmod/rfc2576.py
index b751c4a..a14e787 100644
--- a/pysnmp/proto/secmod/rfc2576.py
+++ b/pysnmp/proto/secmod/rfc2576.py
@@ -103,7 +103,7 @@ class SnmpV1SecurityModel(base.AbstractSecurityModel):
         # rfc2576: 5.2.2
         msg, = globalData
         contextEngineId, contextName, pdu = scopedPDU
-        cachedSecurityData = self._cachePop(securityStateReference)
+        cachedSecurityData = self._cache.pop(securityStateReference)
         communityName = cachedSecurityData['communityName']
 
         debug.logger & debug.flagSM and debug.logger('generateResponseMsg: recovered community %s by securityStateReference %s' % (communityName, securityStateReference))
@@ -238,7 +238,7 @@ class SnmpV1SecurityModel(base.AbstractSecurityModel):
 
         debug.logger & debug.flagSM and debug.logger('processIncomingMsg: looked up securityName %s contextEngineId %s contextName %s by communityName %s' % (securityName, contextEngineId, contextName, communityName))
 
-        stateReference = self._cachePush(
+        stateReference = self._cache.push(
             communityName=communityName.syntax
             )
         
diff --git a/pysnmp/proto/secmod/rfc3414/service.py b/pysnmp/proto/secmod/rfc3414/service.py
index df1c25e..82b3b7a 100644
--- a/pysnmp/proto/secmod/rfc3414/service.py
+++ b/pysnmp/proto/secmod/rfc3414/service.py
@@ -197,7 +197,7 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
         # 3.1.1
         if securityStateReference is not None:
             # 3.1.1a
-            cachedSecurityData = self._cachePop(securityStateReference)
+            cachedSecurityData = self._cache.pop(securityStateReference)
             usmUserName = cachedSecurityData['msgUserName']
             if 'usmUserAuthProtocol' in cachedSecurityData:
                 usmUserAuthProtocol = cachedSecurityData['usmUserAuthProtocol']
@@ -499,7 +499,7 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
 
         # 3.2.2
         msgAuthoritativeEngineID = securityParameters.getComponentByPosition(0)
-        securityStateReference = self._cachePush(
+        securityStateReference = self._cache.push(
             msgUserName=securityParameters.getComponentByPosition(3)
             )
 
@@ -612,8 +612,8 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
         debug.logger & debug.flagSM and debug.logger('processIncomingMsg: now have usmUserSecurityName %s usmUserAuthProtocol %s usmUserPrivProtocol %s for msgUserName %s' % (usmUserSecurityName, usmUserAuthProtocol, usmUserPrivProtocol, msgUserName))
 
         # 3.2.11 (moved up here to let Reports be authenticated & encrypted)
-        self._cachePop(securityStateReference)
-        securityStateReference = self._cachePush(
+        self._cache.pop(securityStateReference)
+        securityStateReference = self._cache.push(
             msgUserName=securityParameters.getComponentByPosition(3),
             usmUserAuthProtocol=usmUserAuthProtocol,
             usmUserAuthKeyLocalized=usmUserAuthKeyLocalized,