fix compiler warning: loop variable creates a copy from type

Signed-off-by: Steffen Pankratz <kratz00@gmx.de>

src/ebusd/main.cpp

@@ -696,7 +696,7 @@ void shutdown(bool error = false) {
     s_messageMap = nullptr;
   }
   // free templates
-  for (const auto it : s_templatesByPath) {
+  for (const auto& it : s_templatesByPath) {
     if (it.second != &s_globalTemplates) {
       delete it.second;
     }

src/lib/ebus/data.cpp

@@ -163,7 +163,7 @@ bool AttributedItem::appendAttributes(OutputFormat outputFormat, ostream* output
     ret = appendAttribute(outputFormat, "comment", true, "[", "]", output) || ret;
   }
   if (outputFormat & OF_ALL_ATTRS) {
-    for (const auto entry : m_attributes) {
+    for (const auto& entry : m_attributes) {
       ret = true;
       if (!entry.second.empty() && entry.first != "unit" && entry.first != "comment") {
         const string& key = entry.first;
@@ -728,13 +728,13 @@ void ValueListDataField::dump(bool prependFieldSeparator, OutputFormat outputFor
   bool first = true;
   if (outputFormat & OF_JSON) {
     *output << ", \"values\": {";
-    for (const auto it : m_values) {
+    for (const auto& it : m_values) {
       appendJson(!first, formatInt(it.first), it.second, true, output);  // TODO optimize?
       first = false;
     }
     *output << " }";
   } else {
-    for (const auto it : m_values) {
+    for (const auto& it : m_values) {
       if (first) {
         first = false;
       } else {
@@ -823,7 +823,7 @@ result_t ConstantDataField::derive(const string& name, PartType partType, int di
     return RESULT_ERR_INVALID_PART;  // cannot create a template from a concrete instance
   }
   string useName = name.empty() ? m_name : name;
-  for (const auto entry : m_attributes) {  // merge with this attributes
+  for (const auto& entry : m_attributes) {  // merge with this attributes
     if ((*attributes)[entry.first].empty()) {
       (*attributes)[entry.first] = entry.second;
     }
@@ -1281,7 +1281,7 @@ result_t LoadableDataFieldSet::addFromFile(const string& filename, unsigned int
 
 DataFieldTemplates::DataFieldTemplates(const DataFieldTemplates& other)
 : MappedFileReader::MappedFileReader(false) {
-  for (const auto it : other.m_fieldsByName) {
+  for (const auto& it : other.m_fieldsByName) {
     m_fieldsByName[it.first] = it.second->clone();
   }
 }

src/lib/ebus/message.cpp

@@ -1689,7 +1689,7 @@ result_t Instruction::create(const string& contextPath, const string& type,
     auto it = row.find("file");
     string arg;
     if (it == row.end()) {
-      for (const auto entry : row) {  // fallback to first field
+      for (const auto& entry : row) {  // fallback to first field
         if (!entry.second.empty()) {
           arg = entry.second;
           break;
@@ -2065,7 +2065,7 @@ result_t MessageMap::addDefaultFromFile(const string& filename, unsigned int lin
     // circuit level additional attributes
   }
   string defaultSuffix = AttributedItem::pluck("suffix", &defaults);
-  for (const auto entry : *row) {
+  for (const auto& entry : *row) {
     string value = entry.second;
     if (entry.first == "circuit" && !defaultCircuit.empty()) {  // TODO remove some day
       if (value.empty()) {
@@ -2445,7 +2445,7 @@ result_t MessageMap::executeInstructions(void (*readMessageFunc)(Message* messag
       it.second = remain;
     }
   }
-  for (const auto it : remove) {
+  for (const auto& it : remove) {
     m_instructions.erase(it);
   }
   return overallResult;
@@ -2551,7 +2551,7 @@ void MessageMap::findAll(const string& circuit, const string& name, const string
   bool checkCircuit = lcircuit.length() > 0;
   bool checkLevel = levels != "*";
   bool checkName = lname.length() > 0;
-  for (const auto it : m_messagesByName) {
+  for (const auto& it : m_messagesByName) {
     if (it.first[0] == FIELD_SEPARATOR) {  // avoid duplicates: instances stored multiple times have a special key
       continue;
     }
@@ -2752,7 +2752,7 @@ void MessageMap::clear() {
     it.second.clear();
   }
   // free remaining message instances by key
-  for (const auto it : m_messagesByKey) {
+  for (const auto& it : m_messagesByKey) {
     vector<Message*> keyMessages = it.second;
     for (auto message : keyMessages) {
       delete message;
@@ -2760,11 +2760,11 @@ void MessageMap::clear() {
     keyMessages.clear();
   }
   // free condition instances
-  for (const auto it : m_conditions) {
+  for (const auto& it : m_conditions) {
     delete it.second;
   }
   // free instruction instances
-  for (const auto it : m_instructions) {
+  for (const auto& it : m_instructions) {
     vector<Instruction*> instructions = it.second;
     for (const auto instruction : instructions) {
       delete instruction;
@@ -2780,7 +2780,7 @@ void MessageMap::clear() {
   m_messagesByKey.clear();
   m_conditions.clear();
   m_instructions.clear();
-  for (const auto it : m_circuitData) {
+  for (const auto& it : m_circuitData) {
     delete it.second;
   }
   m_circuitData.clear();
@@ -2816,7 +2816,7 @@ void MessageMap::dump(bool withConditions, OutputFormat outputFormat, ostream* o
   if (!(outputFormat & OF_SHORT)) {
     *output << endl;
   }
-  for (const auto it : m_messagesByName) {
+  for (const auto& it : m_messagesByName) {
     if (it.first[0] == FIELD_SEPARATOR) {  // skip instances stored multiple times (key starting with "-")
       continue;
     }