changed preview generator functions to a static function

io/loadthread.cpp

@@ -649,7 +649,7 @@ void LoadThread::run() {
     emit success(); // run in main thread
 
     for (int i=0;i<loaded_media_items.size();i++) {
-      PreviewGenerator* pg = new PreviewGenerator(loaded_media_items.at(i));
+      PreviewGenerator::AnalyzeMedia(loaded_media_items.at(i));
     }
   } else {
     if (error_str.isEmpty()) {

io/previewgenerator.cpp

@@ -593,3 +593,11 @@ void PreviewGenerator::cancel() {
   cancelled_ = true;
   wait();
 }
+
+void PreviewGenerator::AnalyzeMedia(Media *m)
+{
+  // PreviewGenerator's constructor starts the thread, sets a reference of itself as the media's generator,
+  // and connects its thread completion to its own deletion, therefore handling its own memory. Nothing else needs to
+  // be done.
+  new PreviewGenerator(m);
+}

io/previewgenerator.h

@@ -42,6 +42,8 @@ public:
   PreviewGenerator(Media*);
   void run();
   void cancel();
+
+  static void AnalyzeMedia(Media*);
 private:
   void parse_media();
   bool retrieve_preview(const QString &hash);

panels/project.cpp

@@ -832,7 +832,7 @@ void Project::process_file_list(QStringList& files, bool recursive, Media* repla
 
       for (int i=0;i<last_imported_media.size();i++) {
         // generate waveform/thumbnail in another thread
-        PreviewGenerator* pg = new PreviewGenerator(last_imported_media.at(i));
+        PreviewGenerator::AnalyzeMedia(last_imported_media.at(i));
       }
     } else {
       delete ca;

project/undo.cpp

@@ -528,7 +528,7 @@ void ReplaceMediaCommand::replace(QString& filename) {
   QStringList files;
   files.append(filename);
   panel_project->process_file_list(files, false, item, nullptr);
-  PreviewGenerator* pg = new PreviewGenerator(item);
+  PreviewGenerator::AnalyzeMedia(item);
 }
 
 void ReplaceMediaCommand::doUndo() {

ui/menuhelper.h

@@ -220,6 +220,6 @@ namespace olive {
      * @brief A global MenuHelper object to assist menu creation throughout Olive.
      */
 extern MenuHelper MenuHelper;
-}
+};
 
 #endif // MENUHELPER_H