core: remove QSettings in qPref* and use a shared variable

Add qPrefPrivate class which contains one QSettings variable,
delete QSettings from qPref* class definitions

this secures there are only instance of QSettings
(QSettings needs to be in a QObject class to work)

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

7 files changed, 43 insertions, 24 deletions

diff --git a/core/settings/qPref.cpp b/core/settings/qPref.cpp
index 027d4af5a..1605e30df 100644
--- a/core/settings/qPref.cpp
+++ b/core/settings/qPref.cpp
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
-#include "qPref_private.h"
+#include "qPrefPrivate.h"
 #include "qPref.h"
 #include "ssrf-version.h"
 
diff --git a/core/settings/qPrefAnimations.cpp b/core/settings/qPrefAnimations.cpp
index a6ecc1d5b..9be8900c5 100644
--- a/core/settings/qPrefAnimations.cpp
+++ b/core/settings/qPrefAnimations.cpp
@@ -1,7 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "qPref.h"
-#include "qPref_private.h"
-#include "qPrefAnimations.h"
+#include "qPrefPrivate.h"
+
+static const QString group = QStringLiteral("Animations");
 
 qPrefAnimations::qPrefAnimations(QObject *parent) : QObject(parent)
 {
diff --git a/core/settings/qPrefAnimations.h b/core/settings/qPrefAnimations.h
index fb58b207e..4971aa06d 100644
--- a/core/settings/qPrefAnimations.h
+++ b/core/settings/qPrefAnimations.h
@@ -3,7 +3,6 @@
 #define QPREFANIMATIONS_H
 
 #include <QObject>
-#include <QSettings>
 
 class qPrefAnimations : public QObject {
 	Q_OBJECT
@@ -28,9 +27,6 @@ signals:
 	void animation_speed_changed(int value);
 
 private:
-	const QString group = QStringLiteral("Animations");
-	QSettings setting;
-
 	// functions to load/sync variable with disk
 	void disk_animation_speed(bool doSync);
 };
diff --git a/core/settings/qPrefDisplay.cpp b/core/settings/qPrefDisplay.cpp
index a248294d1..55a0129a9 100644
--- a/core/settings/qPrefDisplay.cpp
+++ b/core/settings/qPrefDisplay.cpp
@@ -1,11 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "qPref.h"
-#include "qPref_private.h"
+#include "qPrefPrivate.h"
 #include "core/subsurface-string.h"
 
 #include <QApplication>
 #include <QFont>
 
+static const QString group = QStringLiteral("Display");
+
 qPrefDisplay::qPrefDisplay(QObject *parent) : QObject(parent)
 {
 }
diff --git a/core/settings/qPrefDisplay.h b/core/settings/qPrefDisplay.h
index 4a1c0ada5..cb6b872f9 100644
--- a/core/settings/qPrefDisplay.h
+++ b/core/settings/qPrefDisplay.h
@@ -3,7 +3,6 @@
 #define QPREFDISPLAY_H
 
 #include <QObject>
-#include <QSettings>
 
 class qPrefDisplay : public QObject {
 	Q_OBJECT
@@ -44,9 +43,6 @@ signals:
 	void theme_changed(const QString& value);
 
 private:
-	const QString group = QStringLiteral("Display");
-	QSettings setting;
-
 	// functions to load/sync variable with disk
 	void disk_divelist_font(bool doSync);
 	void disk_font_size(bool doSync);
diff --git a/core/settings/qPrefPrivate.cpp b/core/settings/qPrefPrivate.cpp
new file mode 100644
index 000000000..53b99c4e5
--- /dev/null
+++ b/core/settings/qPrefPrivate.cpp
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "qPrefPrivate.h"
+
+qPrefPrivate::qPrefPrivate(QObject *parent) : QObject(parent)
+{
+}
+qPrefPrivate *qPrefPrivate::instance()
+{
+	static qPrefPrivate *self = new qPrefPrivate;
+	return self;
+}
diff --git a/core/settings/qPref_private.h b/core/settings/qPrefPrivate.h
index de06029fa..e4131e9e4 100644
--- a/core/settings/qPref_private.h
+++ b/core/settings/qPrefPrivate.h
@@ -9,6 +9,19 @@
 #include <QObject>
 #include "core/qthelper.h"
 
+// implementation class of the interface classes
+class qPrefPrivate : public QObject {
+    Q_OBJECT
+
+public:
+    static qPrefPrivate *instance();
+
+	QSettings setting;
+
+private:
+    qPrefPrivate(QObject *parent = NULL);
+};
+
 //****** Macros to be used in the set functions ******
 #define COPY_TXT(name, string) \
 { \
@@ -20,49 +33,49 @@
 #define LOADSYNC_BOOL(name, field) \
 { \
 	if (doSync)	\
-		setting.setValue(group + name, prefs.field); \
+		qPrefPrivate::instance()->setting.setValue(group + name, prefs.field); \
 	else \
-		prefs.field = setting.value(group + name, default_prefs.field).toBool(); \
+		prefs.field = qPrefPrivate::instance()->setting.value(group + name, default_prefs.field).toBool(); \
 }
 
 #define LOADSYNC_DOUBLE(name, field) \
 { \
 	if (doSync)	\
-		setting.setValue(group + name, prefs.field); \
+		qPrefPrivate::instance()->setting.setValue(group + name, prefs.field); \
 	else \
-		prefs.field = setting.value(group + name, default_prefs.field).toDouble(); \
+		prefs.field = qPrefPrivate::instance()->setting.value(group + name, default_prefs.field).toDouble(); \
 }
 
 #define LOADSYNC_ENUM(name, type, field) \
 { \
 	if (doSync)	\
-		setting.setValue(group + name, prefs.field); \
+		qPrefPrivate::instance()->setting.setValue(group + name, prefs.field); \
 	else \
-		prefs.field = (enum type)setting.value(group + name, default_prefs.field).toInt(); \
+		prefs.field = (enum type)qPrefPrivate::instance()->setting.value(group + name, default_prefs.field).toInt(); \
 }
 
 #define LOADSYNC_INT(name, field) \
 { \
 	if (doSync) \
-		setting.setValue(group + name, prefs.field); \
+		qPrefPrivate::instance()->setting.setValue(group + name, prefs.field); \
 	else \
-		prefs.field = setting.value(group + name, default_prefs.field).toInt(); \
+		prefs.field = qPrefPrivate::instance()->setting.value(group + name, default_prefs.field).toInt(); \
 }
 
 #define LOADSYNC_INT_DEF(name, field, defval) \
 { \
 	if (doSync)	\
-		setting.setValue(group + name, prefs.field); \
+		qPrefPrivate::instance()->setting.setValue(group + name, prefs.field); \
 	else \
-		prefs.field = setting.value(group + name, defval).toInt(); \
+		prefs.field = qPrefPrivate::instance()->setting.value(group + name, defval).toInt(); \
 }
 
 #define LOADSYNC_TXT(name, field) \
 { \
 	if (doSync)	\
-		setting.setValue(group + name, prefs.field); \
+		qPrefPrivate::instance()->setting.setValue(group + name, prefs.field); \
 	else \
-		prefs.field = copy_qstring(setting.value(group + name, default_prefs.field).toString()); \
+		prefs.field = copy_qstring(qPrefPrivate::instance()->setting.value(group + name, default_prefs.field).toString()); \
 }
 
 //******* Macros to generate disk function