[trac930] modify statistics.cc

 - Add implementation to validate statistics data
   -- When validation is success, it sends data to statistics
   module. But when it fails, it doesn't send and logs the message.

 - Add the function to register the validation function into the class

src/bin/auth/statistics.cc

@@ -37,11 +37,14 @@ public:
     void inc(const AuthCounters::CounterType type);
     bool submitStatistics() const;
     void setStatisticsSession(isc::cc::AbstractSession* statistics_session);
+    void registerStatisticsValidator
+    (AuthCounters::validator_type validator);
     // Currently for testing purpose only
     uint64_t getCounter(const AuthCounters::CounterType type) const;
 private:
     std::vector<uint64_t> counters_;
     isc::cc::AbstractSession* statistics_session_;
+    AuthCounters::validator_type validator_;
 };
 
 AuthCountersImpl::AuthCountersImpl() :
@@ -78,6 +81,14 @@ AuthCountersImpl::submitStatistics() const {
                       << "]}";
     isc::data::ConstElementPtr statistics_element =
         isc::data::Element::fromJSON(statistics_string);
+    // validate the statistics data before send
+    if (validator_) {
+        if (!validator_(
+                statistics_element->get("command")->get(1)->get("data"))) {
+            LOG_ERROR(auth_logger, AUTH_INVALID_STATISTICS_DATA);
+            return (false);
+        }
+    }
     try {
         // group_{send,recv}msg() can throw an exception when encountering
         // an error, and group_recvmsg() will throw an exception on timeout.
@@ -106,6 +117,13 @@ AuthCountersImpl::setStatisticsSession
     statistics_session_ = statistics_session;
 }
 
+void
+AuthCountersImpl::registerStatisticsValidator
+    (AuthCounters::validator_type validator)
+{
+    validator_ = validator;
+}
+
 // Currently for testing purpose only
 uint64_t
 AuthCountersImpl::getCounter(const AuthCounters::CounterType type) const {
@@ -140,3 +158,10 @@ uint64_t
 AuthCounters::getCounter(const AuthCounters::CounterType type) const {
     return (impl_->getCounter(type));
 }
+
+void
+AuthCounters::registerStatisticsValidator
+    (AuthCounters::validator_type validator) const
+{
+    return (impl_->registerStatisticsValidator(validator));
+}