UI: Add frontend API to defer saving

Allows the ability to perform multiple actions that would normally save,
and defer the save until all of those actions are complete.

Closes obsproject/obs-studio#1231

UI/api-interface.cpp

@@ -329,6 +329,16 @@ struct OBSStudioAPI : obs_frontend_callbacks {
 		main->SaveProject();
 	}
 
+	void obs_frontend_defer_save_begin(void) override
+	{
+		QMetaObject::invokeMethod(main, "DeferSaveBegin");
+	}
+
+	void obs_frontend_defer_save_end(void) override
+	{
+		QMetaObject::invokeMethod(main, "DeferSaveEnd");
+	}
+
 	void obs_frontend_add_save_callback(obs_frontend_save_cb callback,
 			void *private_data) override
 	{

UI/obs-frontend-api/obs-frontend-api.cpp

@@ -297,6 +297,18 @@ void obs_frontend_save(void)
 		c->obs_frontend_save();
 }
 
+void obs_frontend_defer_save_begin(void)
+{
+	if (callbacks_valid())
+		c->obs_frontend_defer_save_begin();
+}
+
+void obs_frontend_defer_save_end(void)
+{
+	if (callbacks_valid())
+		c->obs_frontend_defer_save_end();
+}
+
 void obs_frontend_add_save_callback(obs_frontend_save_cb callback,
 		void *private_data)
 {

UI/obs-frontend-api/obs-frontend-api.h

@@ -150,6 +150,8 @@ EXPORT void obs_frontend_replay_buffer_stop(void);
 EXPORT bool obs_frontend_replay_buffer_active(void);
 
 EXPORT void obs_frontend_save(void);
+EXPORT void obs_frontend_defer_save_begin(void);
+EXPORT void obs_frontend_defer_save_end(void);
 
 EXPORT obs_output_t *obs_frontend_get_streaming_output(void);
 EXPORT obs_output_t *obs_frontend_get_recording_output(void);

UI/obs-frontend-api/obs-frontend-internal.hpp

@@ -61,7 +61,9 @@ struct obs_frontend_callbacks {
 	virtual config_t *obs_frontend_get_profile_config(void)=0;
 	virtual config_t *obs_frontend_get_global_config(void)=0;
 
-	virtual void obs_frontend_save(void)=0;
+	virtual void obs_frontend_save(void) = 0;
+	virtual void obs_frontend_defer_save_begin(void) = 0;
+	virtual void obs_frontend_defer_save_end(void) = 0;
 	virtual void obs_frontend_add_save_callback(
 			obs_frontend_save_cb callback, void *private_data)=0;
 	virtual void obs_frontend_remove_save_callback(

UI/window-basic-main.cpp

@@ -550,6 +550,19 @@ void OBSBasic::Save(const char *file)
 	obs_data_array_release(savedMultiviewProjectorList);
 }
 
+void OBSBasic::DeferSaveBegin()
+{
+	os_atomic_inc_long(&disableSaving);
+}
+
+void OBSBasic::DeferSaveEnd()
+{
+	long result = os_atomic_dec_long(&disableSaving);
+	if (result == 0) {
+		SaveProject();
+	}
+}
+
 static void LoadAudioDevice(const char *name, int channel, obs_data_t *parent)
 {
 	obs_data_t *data = obs_data_get_obj(parent, name);

UI/window-basic-main.hpp

@@ -380,6 +380,9 @@ private:
 		obs_data_array_t *savedMultiviewProjectors);
 
 public slots:
+	void DeferSaveBegin();
+	void DeferSaveEnd();
+
 	void StartStreaming();
 	void StopStreaming();
 	void ForceStopStreaming();