separate resolving+scanning to own interface+class and avoid use of extern

src/lib/ebus/message.cpp

@@ -94,11 +94,6 @@ static const char* defaultMessageFieldMap[] = {  // access level not included in
 /** the m_pollOrder of the last polled message. */
 static unsigned int g_lastPollOrder = 0;
 
-extern DataFieldTemplates* getTemplates(const string& filename);
-
-extern result_t loadDefinitionsFromConfigPath(FileReader* reader, const string& filename, bool verbose,
-    map<string, string>* defaults, string* errorDescription, bool replace = false);
-
 
 Message::Message(const string& filename, const string& circuit, const string& level, const string& name,
     bool isWrite, bool isPassive, const map<string, string>& attributes,
@@ -1738,7 +1733,11 @@ void Instruction::getDestination(ostringstream* ostream) const {
 
 result_t LoadInstruction::execute(MessageMap* messages, ostringstream* log) {
   string errorDescription;
-  result_t result = loadDefinitionsFromConfigPath(messages, m_filename, false, &m_defaults, &errorDescription);
+  Resolver* resolver = messages->getResolver();
+  if (!resolver) {
+    return RESULT_ERR_MISSING_ARG;
+  }
+  result_t result = resolver->loadDefinitionsFromConfigPath(messages, m_filename, &m_defaults, &errorDescription);
   if (log->tellp() > 0) {
     *log << ", ";
   }
@@ -2306,7 +2305,10 @@ result_t MessageMap::addFromFile(const string& filename, unsigned int lineNo, ma
     return RESULT_ERR_INVALID_ARG;
   }
   result = RESULT_ERR_EOF;
-  DataFieldTemplates* templates = getTemplates(filename);
+  if (!m_resolver) {
+    return result;
+  }
+  DataFieldTemplates* templates = m_resolver->getTemplates(filename);
   bool hasMulti = types.find(VALUE_SEPARATOR) != string::npos;
   istringstream stream(types);
   string type;

src/lib/ebus/message.h

@@ -1255,6 +1255,43 @@ class LoadedFileInfo {
 };
 
 
+/**
+ * Interface for resolving templates and loading additional message definitions.
+ */
+class Resolver {
+ public:
+  /**
+   * Constructor.
+   */
+  Resolver() {}
+
+  /**
+   * Destructor.
+   */
+  virtual ~Resolver() {}
+
+  /**
+   * Get the @a DataFieldTemplates for the specified configuration file.
+   * @param filename the full name of the configuration file, or "*" to get the non-root templates with the longest name
+   * or the root templates if not available.
+   * @return the @a DataFieldTemplates.
+   */
+  virtual DataFieldTemplates* getTemplates(const string& filename) = 0;
+
+  /**
+   * Load definitions from a relative file from the config path/URL.
+   * @param reader the @a FileReader instance to load with the definitions.
+   * @param filename the relative name of the file being read.
+   * @param defaults the default values by name (potentially overwritten by file name), or nullptr to not use defaults.
+   * @param errorDescription a string in which to store the error description in case of error.
+   * @param replace whether to replace an already existing entry.
+   * @return @a RESULT_OK on success, or an error code.
+   */
+  virtual result_t loadDefinitionsFromConfigPath(FileReader* reader, const string& filename,
+      map<string, string>* defaults, string* errorDescription, bool replace = false) = 0;
+};
+
+
 /**
  * Holds a map of all known @a Message instances.
  */
@@ -1267,7 +1304,7 @@ class MessageMap : public MappedFileReader {
    * @param deleteData whether to delete the scan message @a DataField during @a Message destruction.
    */
   explicit MessageMap(bool addAll = false, const string& preferLanguage = "", bool deleteData = true)
-  : MappedFileReader::MappedFileReader(true, preferLanguage),
+  : MappedFileReader::MappedFileReader(true, preferLanguage), m_resolver(nullptr),
     m_addAll(addAll), m_additionalScanMessages(false), m_maxIdLength(0), m_maxBroadcastIdLength(0),
     m_messageCount(0), m_conditionalMessageCount(0), m_passiveMessageCount(0) {
     m_scanMessage = Message::createScanMessage(false, deleteData);
@@ -1289,6 +1326,17 @@ class MessageMap : public MappedFileReader {
     }
   }
 
+  /**
+   * Set the @a Resolver instance.
+   * @param the @a Resolver instance.
+   */
+  void setResolver(Resolver* resolver) { m_resolver = resolver; }
+
+  /**
+   * @return the @a Resolver instance.
+   */
+  Resolver* getResolver() const { return m_resolver; }
+
   /**
    * Add a @a Message instance to this set.
    * @param message the @a Message instance to add.
@@ -1575,6 +1623,9 @@ class MessageMap : public MappedFileReader {
   /** empty vector for @a getLoadedFiles(). */
   static vector<string> s_noFiles;
 
+  /** the @a Resolver instance. */
+  Resolver* m_resolver;
+
   /** whether to add all messages, even if duplicate. */
   const bool m_addAll;
 

src/lib/ebus/test/test_message.cpp

@@ -54,27 +54,29 @@ DataFieldTemplates* templates = nullptr;
 
 namespace ebusd {
 
-DataFieldTemplates* getTemplates(const string& filename) {
-  if (filename == "") {  // avoid compiler warning
+class TestResolver : public Resolver {
+ public:
+  virtual DataFieldTemplates* getTemplates(const string& filename) {
+    if (filename == "") {  // avoid compiler warning
+      return templates;
+    }
     return templates;
   }
-  return templates;
-}
 
-result_t loadDefinitionsFromConfigPath(FileReader* reader, const string& filename, bool verbose,
-    map<string, string>* defaults, string* errorDescription, bool replace = false) {
-  time_t mtime = 0;
-  istream* stream = FileReader::openFile(filename, errorDescription, &mtime);
-  result_t result;
-  if (stream) {
-    result = reader->readFromStream(stream, filename, mtime, verbose, defaults, errorDescription);
-    delete(stream);
-  } else {
-    result = RESULT_ERR_NOTFOUND;
+  virtual result_t loadDefinitionsFromConfigPath(FileReader* reader, const string& filename,
+      map<string, string>* defaults, string* errorDescription, bool replace = false) {
+    time_t mtime = 0;
+    istream* stream = FileReader::openFile(filename, errorDescription, &mtime);
+    result_t result;
+    if (stream) {
+      result = reader->readFromStream(stream, filename, mtime, false, defaults, errorDescription);
+      delete(stream);
+    } else {
+      result = RESULT_ERR_NOTFOUND;
+    }
+    return result;
   }
-  return result;
-}
-
+};
 
 }  // namespace ebusd
 
@@ -208,6 +210,7 @@ int main() {
   templates->readLineFromStream(&dummystr, __FILE__, false, &lineNo, &row, &errorDescription, false, nullptr, nullptr);
   lineNo = 0;
   MessageMap* messages = new MessageMap("");
+  messages->setResolver(new TestResolver());
   dummystr.clear();
   dummystr.str("#");
   messages->readLineFromStream(&dummystr, __FILE__, false, &lineNo, &row, &errorDescription, false, nullptr, nullptr);