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.
  - Change this raw for-loop to a range for-loop or an "std::for_each".

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

@@ -23,9 +23,6 @@
 
 namespace modsecurity_test
 {
-
-    CustomDebugLog::~CustomDebugLog() {}
-
     void CustomDebugLog::write(int level, const std::string &message)
     {
         m_log << "[" << level << "] " << message << std::endl;
@@ -39,14 +36,14 @@ 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

@@ -107,17 +107,17 @@ void actions(ModSecurityTestResults<RegressionTest> *r,
         {
             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;
         }
     }
 }
@@ -329,10 +329,10 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
 
         actions(&r, &modsec_transaction, &context.m_server_log);
 
-        for (const auto &headers : t->request_headers)
+        for (const auto &[name, value] : t->request_headers)
         {
-            modsec_transaction.addRequestHeader(headers.first.c_str(),
-                                                 headers.second.c_str());
+            modsec_transaction.addRequestHeader(name.c_str(),
+                                                 value.c_str());
         }
 
         modsec_transaction.processRequestHeaders();
@@ -344,10 +344,10 @@ 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)
+        for (const auto &[name, value] : t->response_headers)
         {
-            modsec_transaction.addResponseHeader(headers.first.c_str(),
-                                                  headers.second.c_str());
+            modsec_transaction.addResponseHeader(name.c_str(),
+                                                  value.c_str());
         }
 
         modsec_transaction.processResponseHeaders(r.status,
@@ -362,7 +362,7 @@ 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))
         {
@@ -530,9 +530,9 @@ int main(int argc, char **argv)
     int counter = 0;
 
     std::list<std::string> keyList;
-    for (const auto &a : test)
+    for (const auto &[name, tests] : test)
     {
-        keyList.push_back(a.first);
+        keyList.push_back(name);
     }
     keyList.sort();
 
@@ -611,13 +611,10 @@ int main(int argc, char **argv)
         std::cout << "disabled test(s)." << RESET << std::endl;
     }
 
-    for (auto a : test)
+    for (auto &[name, vec] : test)
     {
-        std::vector<RegressionTest *> *vec = a.second;
-        for (int i = 0; i < vec->size(); i++)
-        {
-            delete vec->at(i);
-        }
+        for (auto x : *vec)
+            delete x;
         delete vec;
     }