Code cleanup: implement window title update via signal

This seems quite convoluted to me but I can't seem to make a more straight
forward implementation work. The idea is that core code should never
directly call into the UI.

So instead the core code (this is C code) calls a helper function. That
helper function calls a member function of a class which in return emits a
signal. The UI code connects to that signal and acts accordingly when it
is received.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

CMakeLists.txt

@@ -274,6 +274,7 @@ set(SUBSURFACE_CORE_LIB_SRCS
 	configuredivecomputer.cpp
 	configuredivecomputerthreads.cpp
 	divesitehelpers.cpp
+	windowtitleupdate.cpp
 	${SUBSURFACE_PRINTING_SRCS}
 	${PLATFORM_SRC}
 )

qt-ui/mainwindow.cpp

@@ -39,6 +39,7 @@
 #include "usersurvey.h"
 #include "divesitehelpers.h"
 #include "locationinformation.h"
+#include "windowtitleupdate.h"
 #ifndef NO_USERMANUAL
 #include "usermanual.h"
 #endif
@@ -148,7 +149,8 @@ MainWindow::MainWindow() : QMainWindow(),
 	connect(locationInformation, SIGNAL(startEditDiveSite(uint32_t)), globeGps, SLOT(prepareForGetDiveCoordinates()));
 	connect(locationInformation, SIGNAL(endEditDiveSite()), globeGps, SLOT(prepareForGetDiveCoordinates()));
 	connect(information(), SIGNAL(diveSiteChanged(uint32_t)), globeGps, SLOT(centerOnDiveSite(uint32_t)));
-
+	wtu = new WindowTitleUpdate();
+	connect(WindowTitleUpdate::instance(), SIGNAL(updateTitle()), this, SLOT(setAutomaticTitle()));
 #ifdef NO_PRINTING
 	plannerDetails->printPlan()->hide();
 	ui.menuFile->removeAction(ui.actionPrint);
@@ -1439,6 +1441,11 @@ QString MainWindow::displayedFilename(QString fullFilename)
 		return fileName;
 }
 
+void MainWindow::setAutomaticTitle()
+{
+	setTitle();
+}
+
 void MainWindow::setTitle(enum MainWindowTitleFormat format)
 {
 	switch (format) {

qt-ui/mainwindow.h

@@ -14,6 +14,7 @@
 
 #include "ui_mainwindow.h"
 #include "notificationwidget.h"
+#include "windowtitleupdate.h"
 
 struct DiveList;
 class QSortFilterProxyModel;
@@ -171,6 +172,7 @@ slots:
 	void on_actionConfigure_Dive_Computer_triggered();
 	void enableDiveSiteEdit(uint32_t id);
 	void setDefaultState();
+	void setAutomaticTitle();
 
 protected:
 	void closeEvent(QCloseEvent *);
@@ -228,6 +230,7 @@ private:
 	};
 	QHash<QByteArray, WidgetForQuadrant> applicationState;
 	QByteArray currentApplicationState;
+	WindowTitleUpdate *wtu;
 };
 
 #endif // MAINWINDOW_H

qthelper.cpp

@@ -1073,11 +1073,6 @@ extern "C" bool canReachCloudServer()
 	return CheckCloudConnection::checkServer();
 }
 
-extern "C" void updateWindowTitle()
-{
-	MainWindow::instance()->setTitle();
-}
-
 extern "C" void subsurface_mkdir(const char *dir)
 {
 	QDir directory;

windowtitleupdate.cpp

@@ -0,0 +1,31 @@
+#include "windowtitleupdate.h"
+
+WindowTitleUpdate *WindowTitleUpdate::m_instance = NULL;
+
+WindowTitleUpdate::WindowTitleUpdate(QObject *parent) : QObject(parent)
+{
+	Q_ASSERT_X(m_Instance == NULL, "WindowTitleUpdate", "WindowTitleUpdate recreated!");
+
+	m_instance = this;
+}
+
+WindowTitleUpdate *WindowTitleUpdate::instance()
+{
+	return m_instance;
+}
+
+WindowTitleUpdate::~WindowTitleUpdate()
+{
+	m_instance = NULL;
+}
+
+void WindowTitleUpdate::emitSignal()
+{
+	emit updateTitle();
+}
+
+extern "C" void updateWindowTitle()
+{
+	WindowTitleUpdate *wt = WindowTitleUpdate::instance();
+	wt->emitSignal();
+}

windowtitleupdate.h

@@ -0,0 +1,20 @@
+#ifndef WINDOWTITLEUPDATE_H
+#define WINDOWTITLEUPDATE_H
+
+#include <QObject>
+
+class WindowTitleUpdate : public QObject
+{
+	Q_OBJECT
+public:
+	explicit WindowTitleUpdate(QObject *parent = 0);
+	~WindowTitleUpdate();
+	static WindowTitleUpdate *instance();
+	void emitSignal();
+signals:
+	void updateTitle();
+private:
+	static WindowTitleUpdate *m_instance;
+};
+
+#endif // WINDOWTITLEUPDATE_H