Use QStringRef to optimize memory allocation

Replace substring functions that return QString with
corresponding functions that return QStringRef where
it's possible.

Create QString from QStringRef only where necessary.

While touching the code, also port loops to C++11 style.

Change-Id: I04c99b24ea6afd3715e3edf9ea00bfab838fd53c
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>
Reviewed-by: Frank Meerkoetter <frank.meerkoetter@basyskom.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

1 files changed, 10 insertions, 8 deletions

diff --git a/src/quick/util/qquickstategroup.cpp b/src/quick/util/qquickstategroup.cpp
index 791e38e45d..c163b401fb 100644
--- a/src/quick/util/qquickstategroup.cpp
+++ b/src/quick/util/qquickstategroup.cpp
@@ -47,6 +47,7 @@
 #include <QtCore/qstringbuilder.h>
 #include <QtCore/qstringlist.h>
 #include <QtCore/qdebug.h>
+#include <QtCore/qvector.h>
 
 #include <private/qobject_p.h>
 #include <qqmlinfo.h>
@@ -379,28 +380,29 @@ QQuickTransition *QQuickStateGroupPrivate::findTransition(const QString &from, c
                       (t->fromState() == QLatin1String("*") &&
                        t->toState() == QLatin1String("*"))))
                 break;
-            QStringList fromState;
-            QStringList toState;
+            const QString fromStateStr = t->fromState();
+            const QString toStateStr = t->toState();
 
-            fromState = t->fromState().split(QLatin1Char(','));
+            QVector<QStringRef> fromState = fromStateStr.splitRef(QLatin1Char(','));
             for (int jj = 0; jj < fromState.count(); ++jj)
                 fromState[jj] = fromState.at(jj).trimmed();
-            toState = t->toState().split(QLatin1Char(','));
+            QVector<QStringRef> toState = toStateStr.splitRef(QLatin1Char(','));
             for (int jj = 0; jj < toState.count(); ++jj)
                 toState[jj] = toState.at(jj).trimmed();
             if (ii == 1)
                 qSwap(fromState, toState);
             int tScore = 0;
-            if (fromState.contains(from))
+            const QString asterisk = QStringLiteral("*");
+            if (fromState.contains(QStringRef(&from)))
                 tScore += 2;
-            else if (fromState.contains(QLatin1String("*")))
+            else if (fromState.contains(QStringRef(&asterisk)))
                 tScore += 1;
             else
                 continue;
 
-            if (toState.contains(to))
+            if (toState.contains(QStringRef(&to)))
                 tScore += 2;
-            else if (toState.contains(QLatin1String("*")))
+            else if (toState.contains(QStringRef(&asterisk)))
                 tScore += 1;
             else
                 continue;