* getVarBindTable() does not filter SNMP exception values anymore

* getVarBindTable() of v1 API now returns Null instead of None
* GETNEXT/GETBULK apps now track EOM condition automatically

8 files changed, 63 insertions, 56 deletions

diff --git a/CHANGES b/CHANGES
index b6e0aed..3da7f43 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,15 @@
 Revision 4.1.15a
 ----------------
 
+- End-of-MIB condition detection reworked what caused backward
+  incompatibility at v1arch GETNEXT API. Previous pysnmp versions
+  used value = None in var-binds as returned by getVarBindTable()
+  API method. This version uses rfc1905 exception values (v2c/v3)
+  or pyasn1 Null (v1).
+  Built-in GETNEXT/GETBULK apps now do not require user to track
+  end-of-mib conditions anymore -- this is now done automatically.
+- SNMP exception values now exported from rfc1905 module, and made
+  pretty printable.
 - Lexicographic walking mode is now supported at oneliner CommandGenerator.
 - ContextEngineId&ContextName parameters passing implemented at
   v3arch oneliner API.
@@ -9,7 +18,6 @@ Revision 4.1.15a
   collide within an administrative domain.
 - MibTableColumn instances now build value-to-column-instance map
   to speedup by-value search.
-- SNMP exception values now exported from rfc1905 module, and made printable.
 - Fix to Next/Bulk CommandGenerators to catch a non-increasing OID
   error condition (what prevents looping).
 - Fix to Opaque value tagging at rfc1155.Opaque type.
diff --git a/examples/v1arch/manager/nextgen.py b/examples/v1arch/manager/nextgen.py
index 08c4575..14dcebd 100644
--- a/examples/v1arch/manager/nextgen.py
+++ b/examples/v1arch/manager/nextgen.py
@@ -7,6 +7,7 @@ from time import time
 
 # Protocol version to use
 pMod = api.protoModules[api.protoVersion1]
+#pMod = api.protoModules[api.protoVersion2c]
 
 # SNMP table header
 headVars = [ pMod.ObjectIdentifier((1,3,6)) ]
@@ -46,14 +47,12 @@ def cbRecvFun(transportDispatcher, transportDomain, transportAddress,
             # Report SNMP table
             for tableRow in varBindTable:
                 for name, val in tableRow:
-                    if val is None:
-                        continue
                     print 'from: %s, %s = %s' % (
                         transportAddress, name.prettyPrint(), val.prettyPrint()
                         )
             # Stop on EOM
             for oid, val in varBindTable[-1]:
-                if val is not None:
+                if not isinstance(val, pMod.Null):
                     break
             else:
                 transportDispatcher.jobFinished(1)
diff --git a/examples/v3arch/manager/bulkgen.py b/examples/v3arch/manager/bulkgen.py
index 4ebeb8a..9c7eb75 100644
--- a/examples/v3arch/manager/bulkgen.py
+++ b/examples/v3arch/manager/bulkgen.py
@@ -36,21 +36,16 @@ def cbFun(sendRequesthandle, errorIndication, errorStatus, errorIndex,
           varBindTable, cbCtx):
     if errorIndication:
         print errorIndication
-        return
+        return  # stop on error
     if errorStatus:
-        print errorStatus.prettyPrint()
-        return
+        print '%s at %s\n' % (
+            errorStatus.prettyPrint(),
+            errorIndex and varBindTable[-1][int(errorIndex)-1] or '?'
+            )        
+        return  # stop on error
     for varBindRow in varBindTable:
         for oid, val in varBindRow:
-            if val is None:
-                print oid.prettyPrint()
-            else:
-                print '%s = %s' % (oid.prettyPrint(), val.prettyPrint())
-    for oid, val in varBindTable[-1]:
-        if val is not None:
-            break
-    else:
-        return # stop on end-of-table
+            print '%s = %s' % (oid.prettyPrint(), val.prettyPrint())
     return 1 # continue walking
 
 cmdgen.BulkCommandGenerator().sendReq(
diff --git a/examples/v3arch/manager/nextgen.py b/examples/v3arch/manager/nextgen.py
index f0b8878..9e9a502 100644
--- a/examples/v3arch/manager/nextgen.py
+++ b/examples/v3arch/manager/nextgen.py
@@ -40,19 +40,14 @@ def cbFun(sendRequestHandle, errorIndication, errorStatus, errorIndex,
     # SNMPv1 response may contain noSuchName error *and* SNMPv2c exception,
     # so we ignore noSuchName error here
     if errorStatus and errorStatus != 2:
-        print errorStatus.prettyPrint()
-        return
+        print '%s at %s\n' % (
+            errorStatus.prettyPrint(),
+            errorIndex and varBindTable[-1][int(errorIndex)-1] or '?'
+            )
+        return  # stop on error
     for varBindRow in varBindTable:
         for oid, val in varBindRow:
-            if val is None:
-                print oid.prettyPrint()
-            else:            
-                print '%s = %s' % (oid.prettyPrint(), val.prettyPrint())
-    for oid, val in varBindTable[-1]:
-        if val is not None:
-            break
-    else:
-        return # stop on end-of-table
+            print '%s = %s' % (oid.prettyPrint(), val.prettyPrint())
     return 1 # continue walking
 
 cmdgen.NextCommandGenerator().sendReq(
diff --git a/pysnmp/entity/rfc3413/cmdgen.py b/pysnmp/entity/rfc3413/cmdgen.py
index cdc8e17..ea7f21d 100644
--- a/pysnmp/entity/rfc3413/cmdgen.py
+++ b/pysnmp/entity/rfc3413/cmdgen.py
@@ -3,6 +3,7 @@ from pysnmp.proto import rfc1157, rfc1905, api
 from pysnmp.entity.rfc3413 import config
 from pysnmp.proto.proxy import rfc2576
 from pysnmp import error, nextid, debug
+from pyasn1.type import univ
 
 getNextHandle = nextid.Integer(0x7fffffff)
                              
@@ -14,6 +15,7 @@ def getVersionSpecifics(snmpVersion):
     return pduVersion, api.protoModules[pduVersion]
 
 class CommandGeneratorBase:
+    _null = univ.Null('')
     def __init__(self):
         self.__pendingReqs = {}
             
@@ -423,13 +425,13 @@ class NextCommandGenerator(CommandGeneratorBase):
         ):
         varBindTable = pMod.apiPDU.getVarBindTable(PDU, rspPDU)
 
-        if not varBindTable:
-            errorIndication = 'emptyResponse'
-        elif pMod.apiPDU.getErrorStatus(rspPDU):
+        if pMod.apiPDU.getErrorStatus(rspPDU):
             errorIndication = None
+        elif not varBindTable:
+            errorIndication = 'emptyResponse'
         else:
             if map(lambda (o,v): o, pMod.apiPDU.getVarBinds(PDU)) < \
-                   map(lambda (o,v): v is None and (9,) or o,varBindTable[-1]):
+                   map(lambda (o,v): isinstance(v, univ.Null) and (9,) or o,varBindTable[-1]):
                 errorIndication = None
             else:
                 debug.logger & debug.flagApp and debug.logger('_handleResponse: sendRequestHandle %s, OID(s) not increasing!' % sendRequestHandle)            
@@ -441,10 +443,16 @@ class NextCommandGenerator(CommandGeneratorBase):
                      varBindTable, cbCtx):
             debug.logger & debug.flagApp and debug.logger('_handleResponse: sendRequestHandle %s, app says to stop walking' % sendRequestHandle)
             return  # app says enough
-        
+
+        for o, v in varBindTable[-1]:
+            if not isinstance(v, univ.Null):
+                break
+        else:
+            return # no more objects available
+    
         pMod.apiPDU.setRequestID(PDU, pMod.getNextRequestID())
         pMod.apiPDU.setVarBinds(
-            PDU, map(lambda (x,y),n=pMod.Null(''): (x,n), varBindTable[-1])
+            PDU, map(lambda (x,y): (x,self._null), varBindTable[-1])
             )
 
         self._sendPdu(
@@ -545,13 +553,13 @@ class BulkCommandGenerator(CommandGeneratorBase):
         ):
         varBindTable = pMod.apiBulkPDU.getVarBindTable(PDU, rspPDU)
 
-        if not varBindTable:
+        if pMod.apiBulkPDU.getErrorStatus(rspPDU):
+            errorIndication = None            
+        elif not varBindTable:
             errorIndication = 'emptyResponse'
-        elif pMod.apiBulkPDU.getErrorStatus(rspPDU):
-            errorIndication = None
         else:
             if map(lambda (o,v): o, pMod.apiBulkPDU.getVarBinds(PDU)) < \
-                   map(lambda (o,v): v is None and (9,) or o,varBindTable[-1]):
+                   map(lambda (o,v): isinstance(v, univ.Null) and (9,) or o,varBindTable[-1]):
                 errorIndication = None
             else:
                 debug.logger & debug.flagApp and debug.logger('_handleResponse: sendRequestHandle %s, OID(s) not increasing!' % sendRequestHandle)            
@@ -566,8 +574,14 @@ class BulkCommandGenerator(CommandGeneratorBase):
 
         pMod.apiBulkPDU.setRequestID(PDU, pMod.getNextRequestID())
 
+        for o, v in varBindTable[-1]:
+            if not isinstance(v, univ.Null):
+                break
+        else:
+            return # no more objects available
+        
         pMod.apiBulkPDU.setVarBinds(
-            PDU, map(lambda (x,y),n=pMod.Null(''): (x,n), varBindTable[-1])
+            PDU, map(lambda (x,y): (x,self._null), varBindTable[-1])
             )
         
         self._sendPdu(
diff --git a/pysnmp/entity/rfc3413/oneliner/cmdgen.py b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
index 08a8d01..ff9a4d3 100644
--- a/pysnmp/entity/rfc3413/oneliner/cmdgen.py
+++ b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
@@ -389,7 +389,7 @@ class CommandGenerator(AsynCommandGenerator):
                 for idx in range(len(varBindTableRow)):
                     name, val = varBindTableRow[idx]
                     # XXX extra rows
-                    if val is not None:
+                    if not isinstance(val, univ.Null):
                         if self.lexicographicMode:
                             if varBindHead[idx] <= name:
                                 break
@@ -441,7 +441,7 @@ class CommandGenerator(AsynCommandGenerator):
                 varBindTableRow = varBindTable[-1]
                 for idx in range(len(varBindTableRow)):
                     name, val = varBindTableRow[idx]
-                    if val is not None:
+                    if not isinstance(val, univ.Null):
                         if self.lexicographicMode:
                             if varBindHead[idx] <= name:
                                 break
diff --git a/pysnmp/proto/api/v1.py b/pysnmp/proto/api/v1.py
index fdc458a..dac8971 100644
--- a/pysnmp/proto/api/v1.py
+++ b/pysnmp/proto/api/v1.py
@@ -41,6 +41,8 @@ apiVarBind = VarBindAPI()
 getNextRequestID = nextid.Integer(0xffff)
 
 class PDUAPI:
+    _null = univ.Null('')
+    
     def setDefaults(self, pdu):
         pdu.setComponentByPosition(0, getNextRequestID())
         pdu.setComponentByPosition(1, 0)
@@ -99,7 +101,9 @@ class PDUAPI:
 
     def getVarBindTable(self, reqPDU, rspPDU):
         if apiPDU.getErrorStatus(rspPDU) == 2:
-            return [ map(lambda (x,y): (x, None), apiPDU.getVarBinds(reqPDU)) ]
+            return [
+                map(lambda (x,y): (x, self._null), apiPDU.getVarBinds(reqPDU))
+                ]
         else:
             return [ apiPDU.getVarBinds(rspPDU) ]
 
diff --git a/pysnmp/proto/api/v2c.py b/pysnmp/proto/api/v2c.py
index 6868452..2d8dc30 100644
--- a/pysnmp/proto/api/v2c.py
+++ b/pysnmp/proto/api/v2c.py
@@ -1,6 +1,5 @@
 from pysnmp.proto import rfc1902, rfc1905, error
 from pysnmp.proto.api import v1
-from pysnmp.smi import exval
 from pyasn1.type import univ, namedtype, namedval
 
 # Shortcuts to SNMP types
@@ -50,20 +49,19 @@ class PDUAPI(v1.PDUAPI):
         return rspPDU
 
     def getVarBindTable(self, reqPDU, rspPDU):
-        varBinds = []
-        for oid, val in apiPDU.getVarBinds(rspPDU):
-            if exval.endOfMib.isSameTypeWith(val):
-                val = None
-            varBinds.append((oid, val))
-        return [ varBinds ]
+        return [ apiPDU.getVarBinds(rspPDU) ]
 
     def setEndOfMibError(self, pdu, errorIndex):
         varBindList = self.getVarBindList(pdu)
-        varBindList[errorIndex-1].setComponentByPosition(1, exval.endOfMib)
+        varBindList[errorIndex-1].setComponentByPosition(
+            1, rfc1905.endOfMibView
+            )
 
     def setNoSuchInstanceError(self, pdu, errorIndex):
         varBindList = self.getVarBindList(pdu)
-        varBindList[errorIndex-1].setComponentByPosition(1,exval.noSuchInstance)
+        varBindList[errorIndex-1].setComponentByPosition(
+            1, rfc1905.noSuchInstance
+            )
 
 apiPDU = PDUAPI()
 
@@ -99,12 +97,6 @@ class BulkPDUAPI(PDUAPI):
         elif N:
             varBindTable.append(rspVarBinds[:N])
 
-        for varBindRow in varBindTable:
-            for idx in range(len(varBindRow)):
-                oid, val = varBindRow[idx]
-                if exval.endOfMib.isSameTypeWith(val):
-                    varBindRow[idx] = (oid, None)
-
         return varBindTable
     
 apiBulkPDU = BulkPDUAPI()