Speed up exit time

Instantiating a single QSettings and using it for each ui element
can significantly shorten the time required to save the various
states at exit. The speed up can be better appreciated on *nix,
where the settings are saved on disk, rather than on Windows where
they are held in memory (in the registry).

(cherry picked from commit 3b43fbfbb1)

src/frontends/qt4/Dialog.cpp

@@ -275,9 +275,8 @@ QString Dialog::sessionKey() const
 }
 
 
-void Dialog::saveSession() const
+void Dialog::saveSession(QSettings & settings) const
 {
-	QSettings settings;
 	settings.setValue(sessionKey() + "/geometry", asQWidget()->saveGeometry());
 }
 

src/frontends/qt4/Dialog.h

@@ -20,6 +20,7 @@
 
 #include <QString>
 
+class QSettings;
 class QWidget;
 
 namespace lyx {
@@ -72,7 +73,7 @@ public:
 	 * This default implementation saves the geometry state.
 	 * Reimplement to save more settings.
 	 **/
-	virtual void saveSession() const;
+	virtual void saveSession(QSettings & settings) const;
 
 	/// Restore session settings.
 	/**

src/frontends/qt4/GuiCharacter.cpp

@@ -466,10 +466,9 @@ void GuiCharacter::dispatchParams()
 }
 
 
-void GuiCharacter::saveSession() const
+void GuiCharacter::saveSession(QSettings & settings) const
 {
-	Dialog::saveSession();
-	QSettings settings;
+	Dialog::saveSession(settings);
 	settings.setValue(sessionKey() + "/toggleall", toggleallCB->isChecked());
 	settings.setValue(sessionKey() + "/autoapply", autoapplyCB->isChecked());
 }

src/frontends/qt4/GuiCharacter.h

@@ -76,7 +76,7 @@ private:
 	void dispatchParams();
 	bool isBufferDependent() const { return true; }
 	FuncCode getLfun() const { return LFUN_TEXTSTYLE_UPDATE; }
-	void saveSession() const;
+	void saveSession(QSettings & settings) const;
 	void restoreSession();
 	//@}
 

src/frontends/qt4/GuiCitation.cpp

@@ -1049,10 +1049,9 @@ BiblioInfo const & GuiCitation::bibInfo() const
 }
 
 
-void GuiCitation::saveSession() const
+void GuiCitation::saveSession(QSettings & settings) const
 {
-	Dialog::saveSession();
-	QSettings settings;
+	Dialog::saveSession(settings);
 	settings.setValue(
 		sessionKey() + "/regex", regexp_->isChecked());
 	settings.setValue(

src/frontends/qt4/GuiCitation.h

@@ -79,7 +79,7 @@ private:
 	void clearParams();
 	void dispatchParams();
 	bool isBufferDependent() const { return true; }
-	void saveSession() const;
+	void saveSession(QSettings & settings) const;
 	void restoreSession();
 	/** Disconnect from the inset when the Apply button is pressed.
 	 *  Allows easy insertion of multiple citations.

src/frontends/qt4/GuiParagraph.cpp

@@ -384,10 +384,9 @@ bool GuiParagraph::hasLabelwidth() const
 }
 
 
-void GuiParagraph::saveSession() const
+void GuiParagraph::saveSession(QSettings & settings) const
 {
-	Dialog::saveSession();
-	QSettings settings;
+	Dialog::saveSession(settings);
 	settings.setValue(sessionKey() + "/autoapply", synchronizedViewCB->isChecked());
 }
 

src/frontends/qt4/GuiParagraph.h

@@ -39,7 +39,7 @@ public:
 	void enableView(bool enable);
 	bool isBufferDependent() const { return true; }
 	virtual FuncCode getLfun() const { return LFUN_PARAGRAPH_PARAMS_APPLY; }
-	void saveSession() const;
+	void saveSession(QSettings & settings) const;
 	void restoreSession();
 	//@}
 

src/frontends/qt4/GuiProgressView.cpp

@@ -232,10 +232,9 @@ void GuiProgressView::appendText(QString const & text)
 }
 
 
-void GuiProgressView::saveSession() const
+void GuiProgressView::saveSession(QSettings & settings) const
 {
-	Dialog::saveSession();
-	QSettings settings;
+	Dialog::saveSession(settings);
 	settings.setValue(
 		sessionKey() + "/autoclear", widget_->autoClearCB->isChecked());
 	settings.setValue(

src/frontends/qt4/GuiProgressView.h

@@ -61,7 +61,7 @@ public:
 	void updateView() {}
 	bool wantInitialFocus() const { return false; }
 	void restoreSession();
-	void saveSession() const;
+	void saveSession(QSettings & settings) const;
 	///@}
 
 private Q_SLOTS:

src/frontends/qt4/GuiToolbar.cpp

@@ -351,9 +351,8 @@ QString GuiToolbar::sessionKey() const
 }
 
 
-void GuiToolbar::saveSession() const
+void GuiToolbar::saveSession(QSettings & settings) const
 {
-	QSettings settings;
 	settings.setValue(sessionKey() + "/visibility", visibility_);
 	settings.setValue(sessionKey() + "/movability", isMovable());
 }

src/frontends/qt4/GuiToolbar.h

@@ -20,6 +20,8 @@
 #include <QToolBar>
 #include <QToolButton>
 
+class QSettings;
+
 namespace lyx {
 
 class DocumentClass;
@@ -84,7 +86,7 @@ public:
 	 **/
 	QString sessionKey() const;
 	/// Save session settings.
-	void saveSession() const;
+	void saveSession(QSettings & settings) const;
 	/// Restore session settings.
 	void restoreSession();
 

src/frontends/qt4/GuiView.cpp

@@ -758,14 +758,16 @@ void GuiView::saveLayout() const
 
 void GuiView::saveUISettings() const
 {
+	QSettings settings;
+
 	// Save the toolbar private states
 	ToolbarMap::iterator end = d.toolbars_.end();
 	for (ToolbarMap::iterator it = d.toolbars_.begin(); it != end; ++it)
-		it->second->saveSession();
+		it->second->saveSession(settings);
 	// Now take care of all other dialogs
 	map<string, DialogPtr>::const_iterator it = d.dialogs_.begin();
 	for (; it!= d.dialogs_.end(); ++it)
-		it->second->saveSession();
+		it->second->saveSession(settings);
 }
 
 

src/frontends/qt4/GuiViewSource.cpp

@@ -367,9 +367,8 @@ void ViewSourceWidget::resizeEvent (QResizeEvent * event)
 }
 
 
-void ViewSourceWidget::saveSession(QString const & session_key) const
+void ViewSourceWidget::saveSession(QSettings & settings, QString const & session_key) const
 {
-	QSettings settings;
 	settings.setValue(session_key + "/output", toqstr(view_format_));
 	settings.setValue(session_key + "/contents", contentsCO->currentIndex());
 	settings.setValue(session_key + "/autoupdate", autoUpdateCB->isChecked());
@@ -462,10 +461,10 @@ void GuiViewSource::updateTitle()
 }
 
 
-void GuiViewSource::saveSession() const
+void GuiViewSource::saveSession(QSettings & settings) const
 {
-	Dialog::saveSession();
-	widget_->saveSession(sessionKey());
+	Dialog::saveSession(settings);
+	widget_->saveSession(settings, sessionKey());
 }
 
 

src/frontends/qt4/GuiViewSource.h

@@ -47,7 +47,7 @@ public:
 	/// returns true if the string has changed
 	bool setText(QString const & qstr = QString());
 	///
-	void saveSession(QString const & session_key) const;
+	void saveSession(QSettings & settings, QString const & session_key) const;
 	///
 	void restoreSession(QString const & session_key);
 	///
@@ -112,7 +112,7 @@ public:
 	bool canApplyToReadOnly() const { return true; }
 	void updateView();
 	void enableView(bool enable);
-	void saveSession() const;
+	void saveSession(QSettings & settings) const;
 	void restoreSession();
 	bool wantInitialFocus() const { return false; }
 	///@}