core: create qPrefUpdateManager from SettingsObjectWrapper

Update set/get functions to follow common name scheme:
- get function have same name as in struct diveComputer
- set function have set_<name>
- signal function have <name>_changed

one class one .h/.cpp is the C++ idiom. Having load/sync of each
variable in 1 functions (in contrast to the distributed way
SettingsObjectWrapper handles it) secures the same storage name
is used. Having the set/get/load/sync functions grouped together
makes it easier to get an overview.

REMARK: this commit only defines the class, it is not active in production

Signed-off-by: Jan Iversen <jani@apache.org>

core/settings/qPrefUpdateManager.h

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef QPREFUPDATEMANAGER_H
+#define QPREFUPDATEMANAGER_H
+#include "core/pref.h"
+
+#include <QObject>
+#include <QDate>
+
+class qPrefUpdateManager : public QObject {
+	Q_OBJECT
+	Q_PROPERTY(bool dont_check_for_updates READ dont_check_for_updates WRITE set_dont_check_for_updates NOTIFY dont_check_for_updates_changed);
+	Q_PROPERTY(bool dont_check_exists READ dont_check_exists WRITE set_dont_check_exists NOTIFY dont_check_exists_changed);
+	Q_PROPERTY(const QString last_version_used READ last_version_used WRITE set_last_version_used NOTIFY last_version_used_changed);
+	Q_PROPERTY(const QDate next_check READ next_check WRITE set_next_check NOTIFY next_check_changed);
+
+public:
+	qPrefUpdateManager(QObject *parent = NULL);
+	static qPrefUpdateManager *instance();
+
+	// Load/Sync local settings (disk) and struct preference
+	void loadSync(bool doSync);
+	void load() { loadSync(false); }
+	void sync() { loadSync(true); }
+
+public:
+	bool dont_check_for_updates() { return prefs.update_manager.dont_check_for_updates; }
+	bool dont_check_exists() { return prefs.update_manager.dont_check_exists; }
+	const QString last_version_used() { return prefs.update_manager.last_version_used; }
+	const QDate next_check() { return QDate::fromString(QString(prefs.update_manager.next_check), "dd/MM/yyyy"); }
+
+public slots:
+	void set_dont_check_for_updates(bool value);
+	void set_dont_check_exists(bool value);
+	void set_last_version_used(const QString& value);
+	void set_next_check(const QDate& value);
+
+signals:
+	void dont_check_for_updates_changed(bool value);
+	void dont_check_exists_changed(bool value);
+	void last_version_used_changed(const QString& value);
+	void next_check_changed(const QDate& value);
+
+private:
+	void disk_dont_check_for_updates(bool doSync);
+	void disk_last_version_used(bool doSync);
+	void disk_next_check(bool doSync);
+};
+
+#endif