core/settings: only sync values that are actually changed

Add a variable reflecting the current_state to all DISK_* macros, in order to
check if the original variable in struct preferences is changed.

Only save to disk if actually changed

[Dirk Hohndel: merged Jan's commit and renamed the variable and adjusted the
               commit message... but fundamentally the commit is still what Jan
               wrote, so he should get the credit]

Signed-off-by: Jan Iversen <jani@apache.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 63 insertions, 21 deletions

diff --git a/core/settings/qPrefPrivate.h b/core/settings/qPrefPrivate.h
index d11e389d3..d4f60542c 100644
--- a/core/settings/qPrefPrivate.h
+++ b/core/settings/qPrefPrivate.h
@@ -29,10 +29,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_BOOL_EXT(usegroup, name, field, usestruct) \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
-		else \
+		static bool current_state; \
+		if (doSync) { \
+			if (current_state != prefs.usestruct field) { \
+				current_state = prefs.usestruct field; \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
+			} \
+		} else { \
 			prefs.usestruct field = qPrefPrivate::propValue(keyFromGroupAndName(group, name), default_prefs.usestruct field).toBool(); \
+			current_state = prefs.usestruct field; \
+		} \
 	}
 #define DISK_LOADSYNC_BOOL(usegroup, name, field) \
 	DISK_LOADSYNC_BOOL_EXT(usegroup, name, field, )
@@ -40,10 +46,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_DOUBLE_EXT(usegroup, name, field, usestruct) \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
-		else \
+		static double current_state; \
+		if (doSync) { \
+			if (current_state != prefs.usestruct field) { \
+				current_state = prefs.usestruct field; \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
+			} \
+		} else { \
 			prefs.usestruct field = qPrefPrivate::propValue(keyFromGroupAndName(group, name), default_prefs.usestruct field).toDouble(); \
+			current_state = prefs.usestruct field; \
+		} \
 	}
 #define DISK_LOADSYNC_DOUBLE(usegroup, name, field) \
 	DISK_LOADSYNC_DOUBLE_EXT(usegroup, name, field, )
@@ -51,10 +63,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_ENUM_EXT(usegroup, name, type, field, usestruct) \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
-		else \
+		static enum type current_state; \
+		if (doSync) { \
+			if (current_state != prefs.usestruct field) { \
+				current_state = prefs.usestruct field; \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
+			} \
+		} else { \
 			prefs.usestruct field = (enum type)qPrefPrivate::propValue(keyFromGroupAndName(group, name), default_prefs.usestruct field).toInt(); \
+			current_state = prefs.usestruct field; \
+		} \
 	}
 #define DISK_LOADSYNC_ENUM(usegroup, name, type, field) \
 	DISK_LOADSYNC_ENUM_EXT(usegroup, name, type, field, )
@@ -62,10 +80,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_INT_EXT(usegroup, name, field, usestruct) \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
-		else \
+		static int current_state; \
+		if (doSync) { \
+			if (current_state != prefs.usestruct field) { \
+				current_state = prefs.usestruct field; \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
+			} \
+		} else { \
 			prefs.usestruct field = qPrefPrivate::propValue(keyFromGroupAndName(group, name), default_prefs.usestruct field).toInt(); \
+			current_state = prefs.usestruct field; \
+		} \
 	}
 #define DISK_LOADSYNC_INT(usegroup, name, field) \
 	DISK_LOADSYNC_INT_EXT(usegroup, name, field, )
@@ -73,10 +97,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_INT_DEF_EXT(usegroup, name, field, defval, usestruct) \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
-		else \
+		static int current_state; \
+		if (doSync) { \
+			if (current_state != prefs.usestruct field) { \
+				current_state = prefs.usestruct field; \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
+			} \
+		} else { \
 			prefs.usestruct field = qPrefPrivate::propValue(keyFromGroupAndName(group, name), defval).toInt(); \
+			current_state = prefs.usestruct field; \
+		} \
 	}
 #define DISK_LOADSYNC_INT_DEF(usegroup, name, field, defval) \
 	DISK_LOADSYNC_INT_DEF_EXT(usegroup, name, field, defval, )
@@ -84,10 +114,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_STRUCT_EXT(usegroup, name, field, var, usestruct)  \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field . var, default_prefs.usestruct field . var); \
-		else \
+		static int current_state; \
+		if (doSync) { \
+			if (current_state != prefs.usestruct field . var) { \
+				current_state = prefs.usestruct field . var; \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field . var, default_prefs.usestruct field . var); \
+			} \
+		} else { \
 			prefs.usestruct field . var = qPrefPrivate::propValue(keyFromGroupAndName(group, name), default_prefs.usestruct field . var).toInt(); \
+			current_state = prefs.usestruct field . var; \
+		} \
 	}
 #define DISK_LOADSYNC_STRUCT(usegroup, name, field, var) \
 	DISK_LOADSYNC_STRUCT_EXT(usegroup, name, field, var, )
@@ -95,10 +131,16 @@ extern QString keyFromGroupAndName(QString group, QString name);
 #define DISK_LOADSYNC_TXT_EXT(usegroup, name, field, usestruct) \
 	void qPref##usegroup::disk_##field(bool doSync) \
 	{ \
-		if (doSync) \
-			qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
-		else \
+		static QString current_state; \
+		if (doSync) { \
+			if (current_state != QString(prefs.usestruct field)) { \
+				current_state = QString(prefs.usestruct field); \
+				qPrefPrivate::propSetValue(keyFromGroupAndName(group, name), prefs.usestruct field, default_prefs.usestruct field); \
+			} \
+		} else { \
 			prefs.usestruct field = copy_qstring(qPrefPrivate::propValue(keyFromGroupAndName(group, name), default_prefs.usestruct field).toString()); \
+			current_state = QString(prefs.usestruct field); \
+		} \
 	}
 #define DISK_LOADSYNC_TXT(usegroup, name, field) \
 	DISK_LOADSYNC_TXT_EXT(usegroup, name, field, )