leverage auto to simplify declarations

- declare objects as references if possible to avoid copies
- declare variables as const if possible to signal that they're not
  modified after initialization

src/transaction.cc

@@ -351,11 +351,9 @@ bool Transaction::extractArguments(const std::string &orig,
         int invalid = 0;
         int changed = 0;
 
-        std::string key;
-        std::string value;
-        std::pair<std::string, std::string> key_value_pair = utils::string::ssplit_pair(t, sep2);
-        key = key_value_pair.first;
-        value = key_value_pair.second;
+        const auto key_value_pair = utils::string::ssplit_pair(t, sep2);
+        const auto &key = key_value_pair.first;
+        const auto &value = key_value_pair.second;
 
         key_s = (key.length() + 1);
         value_s = (value.length() + 1);
@@ -1430,12 +1428,11 @@ int Transaction::processLogging() {
 
         if (!this->m_auditLogModifier.empty()) {
             ms_dbg(4, "There was an audit log modifier for this transaction.");
-            std::list<std::pair<int, std::string>>::iterator it;
             ms_dbg(7, "AuditLog parts before modification(s): " +
                 std::to_string(parts) + ".");
-            for (it = m_auditLogModifier.begin();
+            for (auto it = m_auditLogModifier.begin();
                 it != m_auditLogModifier.end(); ++it) {
-                std::pair <int, std::string> p = *it;
+                const auto &p = *it;
                 if (p.first == 0) {  // Add
                     parts = this->m_rules->m_auditLog->addParts(parts,
                         p.second);

test/regression/regression.cc

@@ -324,7 +324,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
         }
 #endif
 
-        for (std::pair<std::string, std::string> headers :
+        for (const auto &headers :
             t->request_headers) {
             modsec_transaction->addRequestHeader(headers.first.c_str(),
                 headers.second.c_str());
@@ -349,7 +349,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
         }
 #endif
 
-        for (std::pair<std::string, std::string> headers :
+        for (const auto &headers :
             t->response_headers) {
             modsec_transaction->addResponseHeader(headers.first.c_str(),
                 headers.second.c_str());
@@ -529,7 +529,7 @@ int main(int argc, char **argv) {
     int counter = 0;
 
     std::list<std::string> keyList;
-    for (std::pair<std::string, std::vector<RegressionTest *> *> a : test) {
+    for (const auto &a : test) {
         keyList.push_back(a.first);
     }
     keyList.sort();
@@ -597,7 +597,7 @@ int main(int argc, char **argv) {
         std::cout << "disabled test(s)." << RESET << std::endl;
     }
 
-    for (std::pair<std::string, std::vector<RegressionTest *> *> a : test) {
+    for (auto a : test) {
         std::vector<RegressionTest *> *vec = a.second;
         for (int i = 0; i < vec->size(); i++) {
             delete vec->at(i);

test/unit/unit.cc

@@ -151,8 +151,8 @@ int main(int argc, char **argv) {
         test.load_tests("test-cases/secrules-language-tests/transformations");
     }
 
-    for (std::pair<std::string, std::vector<UnitTest *> *> a : test) {
-        std::vector<UnitTest *> *tests = a.second;
+    for (auto a : test) {
+        auto *tests = a.second;
 
         total += tests->size();
         for (UnitTest *t : *tests) {
@@ -217,8 +217,8 @@ int main(int argc, char **argv) {
         }
     }
 
-    for (std::pair<std::string, std::vector<UnitTest *> *> a : test) {
-        std::vector<UnitTest *> *vec = a.second;
+    for (auto a : test) {
+        auto *vec = a.second;
         for (int i = 0; i < vec->size(); i++) {
             delete vec->at(i);
         }