[1808-2] extracted NSEC-getting code for normal NXRRSET case to a helper func.

this simplifies the main code, and avoids using the same log ID twice.

src/lib/datasrc/memory_datasrc.cc

@@ -1255,6 +1255,24 @@ struct InMemoryZoneFinder::InMemoryZoneFinderImpl {
         }
     }
 
+    // A helper function for the NXRRSET case in find().  If the zone is
+    // NSEC-signed and DNSSEC records are requested, try to find NSEC
+    // on the given node, and return it if found; return NULL for all other
+    // cases.
+    ConstRBNodeRRsetPtr getNSECForNXRRSET(FindOptions options,
+                                          const DomainNode& node) const
+    {
+        if (zone_data_->nsec_signed_ &&
+            (options & ZoneFinder::FIND_DNSSEC) != 0) {
+            const Domain::const_iterator found =
+                node.getData()->find(RRType::NSEC());
+            if (found != node.getData()->end()) {
+                return (found->second);
+            }
+        }
+        return (ConstRBNodeRRsetPtr());
+    }
+
     // Set up FindContext object as a return value of find(), taking into
     // account wildcard matches and DNSSEC information.  We set the NSEC/NSEC3
     // flag when applicable regardless of the find option; the caller would
@@ -1367,23 +1385,9 @@ struct InMemoryZoneFinder::InMemoryZoneFinderImpl {
                                           rename));
             }
         }
-        // No exact match or CNAME. This is NXRRSET case. If with DNSSEC query,
-        // get the NSEC RRset, returns with result code NXRRSET.
-        if (zone_data_->nsec_signed_ && (options & ZoneFinder::FIND_DNSSEC) != 0) {
-            found = node->getData()->find(RRType::NSEC());
-            if (found != node->getData()->end()) {
-                LOG_DEBUG(logger, DBG_TRACE_DATA, DATASRC_MEM_NXRRSET).arg(type).
-                          arg(name);
-                return (createFindResult(NXRRSET,
-                                          prepareRRset(name, found->second,
-                                                       rename, options),
-                                                       rename));
-            }
-        }
-        // No exact match or CNAME.  Return NXRRSET.
-        LOG_DEBUG(logger, DBG_TRACE_DATA, DATASRC_MEM_NXRRSET).arg(type).
-            arg(name);
-        return (createFindResult(NXRRSET, ConstRBNodeRRsetPtr(), rename));
+        // No exact match or CNAME.  Get NSEC if necessary and return NXRRSET.
+        return (createFindResult(NXRRSET, getNSECForNXRRSET(options, *node),
+                                 rename));
     }
 };