Use QStringBuilder more

Change-Id: If5283e364e921d99ffa7a8fa1abb07356a4a2682
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/corelib/io/qsettings_mac.cpp

@@ -425,8 +425,7 @@ QMacSettingsPrivate::QMacSettingsPrivate(QSettings::Scope scope, const QString &
     suiteId = javaPackageName;
 
     if (!application.isEmpty()) {
-        javaPackageName += QLatin1Char('.');
-        javaPackageName += application;
+        javaPackageName += QLatin1Char('.') + application;
         applicationId = javaPackageName;
     }
 

src/sql/models/qsqltablemodel.cpp

@@ -986,8 +986,8 @@ QString QSqlTableModel::orderByClause() const
 
     //we can safely escape the field because it would have been obtained from the database
     //and have the correct case
-    QString field = d->db.driver()->escapeIdentifier(f.name(), QSqlDriver::FieldName);
-    field.prepend(QLatin1Char('.')).prepend(d->tableName);
+    QString field = d->tableName + QLatin1Char('.')
+            + d->db.driver()->escapeIdentifier(f.name(), QSqlDriver::FieldName);
     field = d->sortOrder == Qt::AscendingOrder ? Sql::asc(field) : Sql::desc(field);
     return Sql::orderBy(field);
 }

src/tools/uic/cpp/cppwriteinitialization.cpp

@@ -48,10 +48,11 @@ namespace {
     // Fixup an enumeration name from class Qt.
     // They are currently stored as "BottomToolBarArea" instead of "Qt::BottomToolBarArea".
     // due to MO issues. This might be fixed in the future.
-    void fixQtEnumerationName(QString& name) {
+    QLatin1String qtEnumerationPrefix(const QString &name) {
         static const QLatin1String prefix("Qt::");
         if (name.indexOf(prefix) != 0)
-            name.prepend(prefix);
+            return prefix;
+        return QLatin1String();
     }
     // figure out the toolbar area of a DOM attrib list.
     // By legacy, it is stored as an integer. As of 4.3.0, it is the enumeration value.
@@ -62,16 +63,12 @@ namespace {
 
         switch (pstyle->kind()) {
         case DomProperty::Number: {
-            QString area = QLatin1String("static_cast<Qt::ToolBarArea>(");
-            area += QString::number(pstyle->elementNumber());
-            area += QLatin1String("), ");
-            return area;
+            return QLatin1String("static_cast<Qt::ToolBarArea>(")
+                   + QString::number(pstyle->elementNumber()) + QLatin1String("), ");
         }
         case DomProperty::Enum: {
-            QString area = pstyle->elementEnum();
-            fixQtEnumerationName(area);
-            area += QLatin1String(", ");
-            return area;
+            const QString area = pstyle->elementEnum();
+            return qtEnumerationPrefix(area) + area + QLatin1String(", ");
         }
         default:
             break;