LP-419 config: merge factory defaults at startup

a simple registry is used to track all configurations ever seen
only new configurations (i.e. not in the registry) are added
merging only applies to plugin and gadget configurations for now

Author: filnet

ground/gcs/src/app/main.cpp

@@ -416,6 +416,7 @@ int runApplication(int argc, char * *argv)
         qDebug() << "main - resetting user settings";
         Utils::resetToFactoryDefaults(settings);
     }
+    Utils::mergeFactoryDefaults(settings);
 
     // override settings with command line provided values
     // take notice that the overridden values will be saved in the user settings and will continue to be effective

ground/gcs/src/libs/utils/settingsutils.cpp

@@ -43,24 +43,31 @@ const QLatin1String CONFIG_OPTION("-D");
 // list of read only QSettings objects containing factory defaults
 QList<QSettings const *> factorySettingsList;
 
-// helper class to manage a simple registry
+/*
+ * Helper class to manage a simple registry
+ * Each entry in the registry is a configuration path
+ * For example : UAVGadgetConfigurations/DialGadget/Attitude
+ * Note that entries are base64 encoded so QSettings does not mess with them
+ */
 class QTCREATOR_UTILS_EXPORT Registry {
 public:
-    Registry(QSettings &settings) : settings(settings)
+    Registry()
     {
-        settings.beginGroup("registry");
+        QSettings settings;
+
+        settings.beginGroup("Registry");
         registry = settings.childKeys();
         settings.endGroup();
-        // qDebug() << "read registry: " << settings.group() << registry;
     }
 
     void save() const
     {
-        // qDebug() << "saving registry: " << settings.group() << registry;
-        settings.beginGroup("registry");
+        QSettings settings;
+
+        settings.beginGroup("Registry");
         settings.remove("");
         foreach(QString entry, registry) {
-            settings.setValue(key(entry), 1);
+            settings.setValue(entry, 1);
         }
         settings.endGroup();
     }
@@ -76,12 +83,11 @@ class QTCREATOR_UTILS_EXPORT Registry {
     }
 
 private:
-    QSettings &settings;
     QStringList registry;
 
     QString key(QString &entry) const
     {
-        return entry;
+        return entry.toUtf8().toBase64();
     }
 };
 
@@ -114,41 +120,56 @@ void copySettings(const QSettings &from, QSettings &to)
 {
     foreach(QString key, from.allKeys()) {
         if (!to.contains(key)) {
-            // qDebug() << "+++" << key <<  from.value(key);
+            // qDebug() << "++" << key <<  from.value(key);
             to.setValue(key, from.value(key));
         } else if (from.value(key) != to.value(key)) {
-            // qDebug() << ">>>" << key <<  from.value(key) << to.value(key);
+            // qDebug() << ">>" << key <<  from.value(key) << to.value(key);
             to.setValue(key, from.value(key));
         }
     }
 }
 
-void mergeSettings(const QSettings &from, QSettings &to)
+void mergeSettings(Registry &registry, const QSettings &from, QSettings &to)
 {
-    const_cast<QSettings &>(from).beginGroup(to.group());
-
-    // registry of all groups ever seen
-    // used to avoid re-adding a group that was deleted by the user
-    Registry registry(to);
+    to.beginGroup(from.group());
 
     // iterate over factory defaults groups
+    // note that merging could be done in smarter way
+    // currently we do a "all or nothing" merge but we could do something more granular
+    // this, would allow, new configuration options to be added to existing configurations
     foreach(QString group, from.childGroups()) {
         const_cast<QSettings &>(from).beginGroup(group);
         to.beginGroup(group);
-        if (!registry.contains(group)) {
+        QString id = from.group();
+        if (!registry.contains(id)) {
             // registry keeps growing...
-            registry.add(group);
-            if (to.allKeys().count() <= 0) {
+            registry.add(id);
+            // copy settings only if destination group is totally empty (see comment above)
+            if (to.allKeys().count() <= 0 && to.childGroups().count() <= 0) {
                 // found new group, copy it to the destination
+                qDebug() << "settings - adding new configuration" << id;
                 copySettings(from, to);
             }
         }
         to.endGroup();
         const_cast<QSettings &>(from).endGroup();
     }
 
-    registry.save();
+    to.endGroup();
+}
 
+void mergeFactorySettings(Registry &registry, const QSettings &from, QSettings &to)
+{
+    const_cast<QSettings &>(from).beginGroup("Plugins");
+    mergeSettings(registry, from, to);
+    const_cast<QSettings &>(from).endGroup();
+
+    const_cast<QSettings &>(from).beginGroup("UAVGadgetConfigurations");
+    foreach(QString childGroup, from.childGroups()) {
+        const_cast<QSettings &>(from).beginGroup(childGroup);
+        mergeSettings(registry, from, to);
+        const_cast<QSettings &>(from).endGroup();
+    }
     const_cast<QSettings &>(from).endGroup();
 }
 
@@ -163,7 +184,7 @@ void initSettings(const QString &factoryDefaultsFileName)
 
     if (fileName.isEmpty()) {
         // check default file
-        qDebug() << "Looking for factory defaults configuration files in" << directory.absolutePath();
+        qDebug() << "settings - looking for factory defaults configuration files in" << directory.absolutePath();
         fileName = checkFile(directory.absoluteFilePath(DEFAULT_CONFIG_FILENAME));
     }
 
@@ -182,7 +203,7 @@ void initSettings(const QString &factoryDefaultsFileName)
         file = checkFile(file);
 
         QSettings const *settings = new QSettings(file, XmlConfig::XmlFormat);
-        qDebug() << "Loaded factory defaults" << file;
+        qDebug() << "settings - loaded factory defaults" << file;
 
         factorySettingsList.append(settings);
     }
@@ -198,7 +219,7 @@ void overrideSettings(QSettings &settings, int argc, char * *argv)
             if (rx.indexIn(argv[++i]) > -1) {
                 QString key   = rx.cap(1);
                 QString value = rx.cap(2);
-                qDebug() << "User setting" << key << "set to value" << value;
+                qDebug() << "settings - user setting" << key << "set to value" << value;
                 settings.setValue(key, value);
             }
         }
@@ -213,10 +234,21 @@ void resetToFactoryDefaults(QSettings &toSettings)
         );
 }
 
+/**
+ * Merge factory defaults into user settings.
+ * Currently only Plugins and UAVGadgetConfigurations are merged
+ */
 void mergeFactoryDefaults(QSettings &toSettings)
 {
+    // registry of all configuration groups ever seen
+    // used to avoid re-adding a group that was deleted by the user
+    Registry registry;
+
+    // merge all loaded factory defaults
     applyToFactorySettings(
-        [&](const QSettings &fromSettings) { mergeSettings(fromSettings, toSettings); }
+        [&](const QSettings &fromSettings) { mergeFactorySettings(registry, fromSettings, toSettings); }
         );
+
+    registry.save();
 }
 }