GH-992 Add a transaction/locking mechanism to settings objects

This can cut the FTB loading by ~66% - worth it, but not ideal.
Real solution will have to be implemented later.

logic/settings/INISettingsObject.cpp

@@ -33,6 +33,20 @@ bool INISettingsObject::reload()
 	return m_ini.loadFile(m_filePath) && SettingsObject::reload();
 }
 
+void INISettingsObject::suspendSave()
+{
+	m_suspendSave = true;
+}
+
+void INISettingsObject::resumeSave()
+{
+	m_suspendSave = false;
+	if(m_doSave)
+	{
+		m_ini.saveFile(m_filePath);
+	}
+}
+
 void INISettingsObject::changeSetting(const Setting &setting, QVariant value)
 {
 	if (contains(setting.id()))
@@ -51,6 +65,18 @@ void INISettingsObject::changeSetting(const Setting &setting, QVariant value)
 			for(auto iter: setting.configKeys())
 				m_ini.remove(iter);
 		}
+		doSave();
+	}
+}
+
+void INISettingsObject::doSave()
+{
+	if(m_suspendSave)
+	{
+		m_doSave = true;
+	}
+	else
+	{
 		m_ini.saveFile(m_filePath);
 	}
 }
@@ -62,7 +88,7 @@ void INISettingsObject::resetSetting(const Setting &setting)
 	{
 		for(auto iter: setting.configKeys())
 			m_ini.remove(iter);
-		m_ini.saveFile(m_filePath);
+		doSave();
 	}
 }
 

logic/settings/INISettingsObject.h

@@ -47,15 +47,18 @@ public:
 
 	bool reload() override;
 
-protected
-slots:
+	void suspendSave();
+	void resumeSave();
+
+protected slots:
 	virtual void changeSetting(const Setting &setting, QVariant value);
 	virtual void resetSetting(const Setting &setting);
 
 protected:
 	virtual QVariant retrieveValue(const Setting &setting);
+	void doSave();
 
+protected:
 	INIFile m_ini;
-
 	QString m_filePath;
 };

logic/settings/SettingsObject.h

@@ -22,6 +22,9 @@
 #include <memory>
 
 class Setting;
+class SettingsObject;
+
+typedef std::shared_ptr<SettingsObject> SettingsObjectPtr;
 
 /*!
  * \brief The SettingsObject handles communicating settings between the application and a
@@ -38,6 +41,22 @@ class Setting;
 class SettingsObject : public QObject
 {
 	Q_OBJECT
+public:
+	class Lock
+	{
+	public:
+		Lock(SettingsObjectPtr locked)
+			:m_locked(locked)
+		{
+			m_locked->suspendSave();
+		}
+		~Lock()
+		{
+			m_locked->resumeSave();
+		}
+	private:
+		SettingsObjectPtr m_locked;
+	};
 public:
 	explicit SettingsObject(QObject *parent = 0);
 	virtual ~SettingsObject();
@@ -127,6 +146,8 @@ public:
 	 */
 	virtual bool reload();
 
+	virtual void suspendSave() = 0;
+	virtual void resumeSave() = 0;
 signals:
 	/*!
 	 * \brief Signal emitted when one of this SettingsObject object's settings changes.
@@ -184,6 +205,7 @@ protected:
 
 private:
 	QMap<QString, std::shared_ptr<Setting>> m_settings;
+protected:
+	bool m_suspendSave = false;
+	bool m_doSave = false;
 };
-
-typedef std::shared_ptr<SettingsObject> SettingsObjectPtr;