Save preferences periodically if they are modified (fix #4154)

src/app/app.cpp

@@ -429,6 +429,15 @@ namespace {
     CloseMainWindow(std::unique_ptr<MainWindow>& win) : m_win(win) { }
     ~CloseMainWindow() { m_win.reset(nullptr); }
   };
+  // Each 10 seconds we save the modified preferences
+  struct SavePreferencesPeriodically {
+    ui::Timer m_timer;
+    SavePreferencesPeriodically() : m_timer(10000) {
+      m_timer.Tick.connect([]{ Preferences::instance().save(); });
+    }
+    ~SavePreferencesPeriodically() { }
+    void start() { m_timer.start(); }
+  };
 #endif
 
   struct CloseAllDocs {
@@ -466,6 +475,7 @@ void App::run()
 {
 #ifdef ENABLE_UI
   CloseMainWindow closeMainWindow(m_mainWindow);
+  SavePreferencesPeriodically savePrefTimer;
 #endif
   CloseAllDocs closeAllDocsAtExit(context());
 
@@ -543,6 +553,8 @@ void App::run()
 
     // Run the GUI main message loop
     try {
+      savePrefTimer.start();
+
       manager->run();
       set_app_state(AppState::kClosing);
     }

src/cfg/cfg.cpp

@@ -65,26 +65,32 @@ public:
   }
 
   void setValue(const char* section, const char* name, const char* value) {
+    m_dirty = true;
     m_ini.SetValue(section, name, value);
   }
 
   void setBoolValue(const char* section, const char* name, bool value) {
+    m_dirty = true;
     m_ini.SetBoolValue(section, name, value);
   }
 
   void setIntValue(const char* section, const char* name, int value) {
+    m_dirty = true;
     m_ini.SetLongValue(section, name, value);
   }
 
   void setDoubleValue(const char* section, const char* name, double value) {
+    m_dirty = true;
     m_ini.SetDoubleValue(section, name, value);
   }
 
   void deleteValue(const char* section, const char* name) {
+    m_dirty = true;
     m_ini.Delete(section, name, true);
   }
 
   void deleteSection(const char* section) {
+    m_dirty = true;
     m_ini.Delete(section, nullptr, true);
   }
 
@@ -101,10 +107,15 @@ public:
         return false;
       }
     }
+
+    m_dirty = false;
     return true;
   }
 
   void save() {
+    if (!m_dirty)
+      return;
+
     base::FileHandle file(base::open_file(m_filename, "wb"));
     if (file) {
       SI_Error err = m_ini.SaveFile(file.get());
@@ -112,12 +123,16 @@ public:
         LOG(ERROR, "CFG: Error %d saving configuration into %s\n",
             (int)err, m_filename.c_str());
       }
+      else {
+        m_dirty = false;
+      }
     }
   }
 
 private:
   std::string m_filename;
   CSimpleIniA m_ini;
+  bool m_dirty = false;
 };
 
 CfgFile::CfgFile()

src/gen/pref_types.cpp

@@ -36,6 +36,7 @@ static void print_pref_class_def(TiXmlElement* elem, const std::string& classNam
   std::cout
     << indent << "  void load();\n"
     << indent << "  void save();\n"
+    << indent << "  bool isDirty() const;\n"
     << indent << "  Section* section(const char* id) override;\n"
     << indent << "  OptionBase* option(const char* id) override;\n";
 
@@ -200,7 +201,9 @@ static void print_pref_class_impl(TiXmlElement* elem, const std::string& prefix,
 
   std::cout
     << "void " << prefix << className << "::save()\n"
-    << "{\n";
+    << "{\n"
+    << "  if (!isDirty())\n"
+    << "    return;\n";
 
   child = (elem->FirstChild() ? elem->FirstChild()->ToElement(): NULL);
   while (child) {
@@ -222,6 +225,33 @@ static void print_pref_class_impl(TiXmlElement* elem, const std::string& prefix,
     << "}\n"
     << "\n";
 
+  // Section::isDirty()
+
+  std::cout
+    << "bool " << prefix << className << "::isDirty() const\n"
+    << "{\n";
+
+  child = (elem->FirstChild() ? elem->FirstChild()->ToElement(): NULL);
+  while (child) {
+    if (child->Value()) {
+      std::string name = child->Value();
+      if (name == "option") {
+        std::string memberName = convert_xmlid_to_cppid(child->Attribute("id"), false);
+        std::cout << "  if (" << memberName << ".isDirty()) return true;\n";
+      }
+      else if (name == "section") {
+        std::string memberName = convert_xmlid_to_cppid(child->Attribute("id"), false);
+        std::cout << "  if (" << memberName << ".isDirty()) return true;\n";
+      }
+    }
+    child = child->NextSiblingElement();
+  }
+
+  std::cout
+    << "  return false;\n"
+    << "}\n"
+    << "\n";
+
   // Section::section(id)
 
   std::cout