Minor codebase improvements suggested by Sonarcloud

- src/modsecurity.cc
  - Replace the redundant type with "auto".
- src/transaction.cc
  - Avoid this unnecessary copy by using a "const" reference.
- test/common/custom_debug_log.cc
  - Use "=default" instead of the default implementation of this special
    member functions.
    - Removed the unnecessary destructor override instead.
  - Annotate this function with "override" or "final".
    - Removed the unnecessary destructor override instead.
  - Remove this "const" qualifier from the return type in all
    declarations.
- test/common/modsecurity_test_context.h
  - Replace the redundant type with "auto".
- test/regression/regression.cc
  - Use the "nullptr" literal.
  - Replace this declaration by a structured binding declaration.
  - Replace "reinterpret_cast" with a safer operation.

src/modsecurity.cc

@@ -199,13 +199,13 @@ void ModSecurity::serverLog(void *data, const RuleMessage &rm) {
 
     if (m_logProperties & TextLogProperty) {
         auto d = rm.log();
-        const void *a = static_cast<const void *>(d.c_str());
+        auto a = static_cast<const void *>(d.c_str());
         m_logCb(data, a);
         return;
     }
 
     if (m_logProperties & RuleMessageLogProperty) {
-        const void *a = static_cast<const void *>(&rm);
+        auto a = static_cast<const void *>(&rm);
         m_logCb(data, a);
         return;
     }

src/transaction.cc

@@ -1529,7 +1529,7 @@ std::string Transaction::toOldAuditLogFormat(int parts,
     }
     if (parts & audit_log::AuditLog::HAuditLogPart) {
         audit_log << "--" << trailer << "-" << "H--" << std::endl;
-        for (auto a : m_rulesMessages) {
+        for (const auto &a : m_rulesMessages) {
             audit_log << a.log(0, m_httpCodeReturned) << std::endl;
         }
         audit_log << std::endl;

test/common/custom_debug_log.cc

@@ -23,8 +23,6 @@
 
 namespace modsecurity_test {
 
-    CustomDebugLog::~CustomDebugLog() {}
-
     void CustomDebugLog::write(int level, const std::string &message) {
         m_log << "[" << level << "] " << message << std::endl;
     }
@@ -36,13 +34,13 @@ namespace modsecurity_test {
         m_log << msgf << std::endl;
     }
 
-    bool const CustomDebugLog::contains(const std::string &pattern) const {
+    bool CustomDebugLog::contains(const std::string &pattern) const {
         modsecurity::Utils::Regex re(pattern);
         std::string s = m_log.str();
         return modsecurity::Utils::regex_search(s, re);
     }
 
-    std::string const CustomDebugLog::log_messages() const {
+    std::string CustomDebugLog::log_messages() const {
         return m_log.str();
     }
 

test/common/custom_debug_log.h

@@ -26,13 +26,12 @@ namespace modsecurity_test {
 class CustomDebugLog : public modsecurity::debug_log::DebugLog {
  public:
     CustomDebugLog *new_instance();
-    ~CustomDebugLog();
 
     void write(int level, const std::string& message) override;
     void write(int level, const std::string &id,
         const std::string &uri, const std::string &msg) override;
-    bool const contains(const std::string& pattern) const;
-    std::string const log_messages() const;
+    bool contains(const std::string& pattern) const;
+    std::string log_messages() const;
     std::string error_log_messages();
     int getDebugLogLevel() override;
 

test/common/modsecurity_test_context.h

@@ -36,8 +36,8 @@ namespace modsecurity_test
     private:
         static void logCb(void *data, const void *msgv)
         {
-            const char *msg = reinterpret_cast<const char *>(msgv);
-            std::stringstream *ss = (std::stringstream *)data;
+            auto msg = reinterpret_cast<const char *>(msgv);
+            auto ss = reinterpret_cast<std::stringstream *>(data);
             *ss << msg << std::endl;
         }
     };

test/regression/regression.cc

@@ -97,15 +97,15 @@ void actions(ModSecurityTestResults<RegressionTest> *r,
         if (it.status != 0) {
             r->status = it.status;
         }
-        if (it.url != NULL) {
+        if (it.url != nullptr) {
             r->location.append(it.url);
 	    free(it.url);
-	    it.url = NULL;
+	    it.url = nullptr;
         }
-        if (it.log != NULL) {
+        if (it.log != nullptr) {
             *serverLog << it.log;
             free(it.log);
-            it.log = NULL;
+            it.log = nullptr;
         }
     }
 }
@@ -283,9 +283,9 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
 
         actions(&r, &modsec_transaction, &context.m_server_log);
 
-        for (const auto &headers : t->request_headers) {
-            modsec_transaction.addRequestHeader(headers.first.c_str(),
-                headers.second.c_str());
+        for (const auto &[name, value] : t->request_headers) {
+            modsec_transaction.addRequestHeader(name.c_str(),
+                value.c_str());
         }
 
         modsec_transaction.processRequestHeaders();
@@ -297,9 +297,9 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
         modsec_transaction.processRequestBody();
         actions(&r, &modsec_transaction, &context.m_server_log);
 
-        for (const auto &headers : t->response_headers) {
-            modsec_transaction.addResponseHeader(headers.first.c_str(),
-                headers.second.c_str());
+        for (const auto &[name, value] : t->response_headers) {
+            modsec_transaction.addResponseHeader(name.c_str(),
+                value.c_str());
         }
 
         modsec_transaction.processResponseHeaders(r.status,
@@ -314,7 +314,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
 
         modsec_transaction.processLogging();
 
-        const auto *d = reinterpret_cast<CustomDebugLog *>(context.m_modsec_rules.m_debugLog);
+        const auto *d = static_cast<CustomDebugLog *>(context.m_modsec_rules.m_debugLog);
 
         if (!d->contains(t->debug_log)) {
             if (test->m_automake_output) {
@@ -455,8 +455,8 @@ int main(int argc, char **argv)
     int counter = 0;
 
     std::list<std::string> keyList;
-    for (const auto &a : test) {
-        keyList.push_back(a.first);
+    for (const auto &[name, tests] : test) {
+        keyList.push_back(name);
     }
     keyList.sort();