Merge second part of #2726

Enable more checks from cppcheck and fix reports caused by that. Fix
also reports produced by different version of cppcheck than the local
one.

src/bin/resolver/resolver.cc

@@ -524,7 +524,8 @@ ResolverImpl::processNormalQuery(const IOMessage& io_message,
 {
     const ConstQuestionPtr question = *query_message->beginQuestion();
     const RRType qtype = question->getType();
-    const RRClass qclass = question->getClass();
+    // Make cppcheck happy with the reference.
+    const RRClass& qclass = question->getClass();
 
     // Apply query ACL
     const Client client(io_message);

src/lib/config/config_data.h

@@ -29,7 +29,7 @@ namespace config {
 /// point to anything defined in the .spec file)
 class DataNotFoundError : public isc::Exception {
 public:
-    DataNotFoundError(const char* file, size_t line, const std::string& what) :
+    DataNotFoundError(const char* file, size_t line, const char* what) :
         isc::Exception(file, line, what) {}
 };
 

src/lib/datasrc/tests/client_list_unittest.cc

@@ -125,6 +125,7 @@ public:
         rrclass_(RRClass::IN()),
         // The empty list corresponds to a list with no elements inside
         list_(new TestedList(rrclass_)),
+        negative_result_(),
         config_elem_(Element::fromJSON("["
             "{"
             "   \"type\": \"test_type\","

src/lib/dns/message.h

@@ -98,10 +98,10 @@ struct SectionIteratorImpl;
 template <typename T>
 class SectionIterator : public std::iterator<std::input_iterator_tag, T> {
 public:
-    SectionIterator<T>() : impl_(NULL) {}
-    SectionIterator<T>(const SectionIteratorImpl<T>& impl);
-    ~SectionIterator<T>();
-    SectionIterator<T>(const SectionIterator<T>& source);
+    SectionIterator() : impl_(NULL) {}
+    SectionIterator(const SectionIteratorImpl<T>& impl);
+    ~SectionIterator();
+    SectionIterator(const SectionIterator<T>& source);
     void operator=(const SectionIterator<T>& source);
     SectionIterator<T>& operator++();
     SectionIterator<T> operator++(int);

src/lib/dns/rdata/any_255/tsig_250.cc

@@ -370,13 +370,13 @@ TSIG::toText() const {
         lexical_cast<string>(impl_->time_signed_) + " " +
         lexical_cast<string>(impl_->fudge_) + " " +
         lexical_cast<string>(impl_->mac_.size()) + " ";
-    if (impl_->mac_.size() > 0) {
+    if (!impl_->mac_.empty()) {
         result += encodeBase64(impl_->mac_) + " ";
     }
     result += lexical_cast<string>(impl_->original_id_) + " ";
     result += TSIGError(impl_->error_).toText() + " ";
     result += lexical_cast<string>(impl_->other_data_.size());
-    if (impl_->other_data_.size() > 0) {
+    if (!impl_->other_data_.empty()) {
         result += " " + encodeBase64(impl_->other_data_);
     }
 
@@ -520,7 +520,7 @@ TSIG::getMACSize() const {
 
 const void*
 TSIG::getMAC() const {
-    if (impl_->mac_.size() > 0) {
+    if (!impl_->mac_.empty()) {
         return (&impl_->mac_[0]);
     } else {
         return (NULL);
@@ -544,7 +544,7 @@ TSIG::getOtherLen() const {
 
 const void*
 TSIG::getOtherData() const {
-    if (impl_->other_data_.size() > 0) {
+    if (!impl_->other_data_.empty()) {
         return (&impl_->other_data_[0]);
     } else {
         return (NULL);

src/lib/log/message_reader.cc

@@ -127,7 +127,7 @@ void
 MessageReader::parsePrefix(const vector<string>& tokens) {
 
     // Should not get here unless there is something in the tokens array.
-    assert(tokens.size() > 0);
+    assert(!tokens.empty());
 
     // Process $PREFIX.  With no arguments, the prefix is set to the empty
     // string.  One argument sets the prefix to the to its value and more than