core: create qPrefPartialPressureGas 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/qPrefPartialPressureGas.h

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef QPREFPARTICULARPRESSUREGAS_H
+#define QPREFPARTICULARPRESSUREGAS_H
+#include "core/pref.h"
+
+#include <QObject>
+
+class qPrefPartialPressureGas : public QObject {
+	Q_OBJECT
+	Q_PROPERTY(bool phe READ phe WRITE set_phe NOTIFY phe_changed);
+	Q_PROPERTY(double phe_threshold READ phe_threshold WRITE set_phe_threshold NOTIFY phe_threshold_changed);
+	Q_PROPERTY(bool pn2 READ pn2 WRITE set_pn2 NOTIFY pn2_changed);
+	Q_PROPERTY(double pn2_threshold READ pn2_threshold WRITE set_pn2_threshold NOTIFY pn2_threshold_changed);
+	Q_PROPERTY(bool po2 READ po2 WRITE set_po2 NOTIFY po2_changed);
+	Q_PROPERTY(double po2_threshold_max READ po2_threshold_max WRITE set_po2_threshold_max NOTIFY po2_threshold_max_changed);
+	Q_PROPERTY(double po2_threshold_min READ po2_threshold_min WRITE set_po2_threshold_min NOTIFY po2_threshold_min_changed);
+
+public:
+	qPrefPartialPressureGas(QObject *parent = NULL);
+	static qPrefPartialPressureGas *instance();
+
+	// Load/Sync local settings (disk) and struct preference
+	void loadSync(bool doSync);
+	void load() { loadSync(false); }
+	void sync() { loadSync(true); }
+
+public:
+	bool phe() { return prefs.pp_graphs.phe; }
+	double phe_threshold() { return prefs.pp_graphs.phe_threshold; }
+	bool pn2() { return prefs.pp_graphs.pn2; }
+	double pn2_threshold() { return prefs.pp_graphs.pn2_threshold; }
+	bool po2() { return prefs.pp_graphs.po2; }
+	double po2_threshold_max() { return prefs.pp_graphs.po2_threshold_max; }
+	double po2_threshold_min() { return prefs.pp_graphs.po2_threshold_min; }
+
+public slots:
+	void set_phe(bool value);
+	void set_phe_threshold(double value);
+	void set_pn2(bool value);
+	void set_pn2_threshold(double value);
+	void set_po2(bool value);
+	void set_po2_threshold_min(double value);
+	void set_po2_threshold_max(double value);
+
+signals:
+	void phe_changed(bool value);
+	void phe_threshold_changed(double value);
+	void pn2_changed(bool value);
+	void pn2_threshold_changed(double value);
+	void po2_changed(bool value);
+	void po2_threshold_max_changed(double value);
+	void po2_threshold_min_changed(double value);
+
+private:
+	void disk_phe(bool doSync);
+	void disk_phe_threshold(bool doSync);
+	void disk_pn2(bool doSync);
+	void disk_pn2_threshold(bool doSync);
+	void disk_po2(bool doSync);
+	void disk_po2_threshold_min(bool doSync);
+	void disk_po2_threshold_max(bool doSync);
+};
+
+#endif