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, 7 insertions, 8 deletions

diff --git a/src/qml/qml/qqmlimport.cpp b/src/qml/qml/qqmlimport.cpp
index ec29e600ed..2a1717f190 100644
--- a/src/qml/qml/qqmlimport.cpp
+++ b/src/qml/qml/qqmlimport.cpp
@@ -85,12 +85,11 @@ QString resolveLocalUrl(const QString &url, const QString &relative)
     } else if (relative.at(0) == Slash || !url.contains(Slash)) {
         return relative;
     } else {
-        QString base(url.left(url.lastIndexOf(Slash) + 1));
-
+        const QStringRef baseRef = url.leftRef(url.lastIndexOf(Slash) + 1);
         if (relative == QLatin1String("."))
-            return base;
+            return baseRef.toString();
 
-        base.append(relative);
+        QString base = baseRef + relative;
 
         // Remove any relative directory elements in the path
         int length = base.length();
@@ -815,11 +814,11 @@ bool QQmlImportNamespace::resolveType(QQmlTypeLoader *typeLoader, const QHashedS
                             QString u1 = import->url;
                             QString u2 = import2->url;
                             if (base) {
-                                QString b = *base;
+                                QStringRef b(base);
                                 int dot = b.lastIndexOf(Dot);
                                 if (dot >= 0) {
                                     b = b.left(dot+1);
-                                    QString l = b.left(dot);
+                                    QStringRef l = b.left(dot);
                                     if (u1.startsWith(b))
                                         u1 = u1.mid(b.count());
                                     else if (u1 == l)
@@ -1173,11 +1172,11 @@ bool QQmlImportsPrivate::locateQmldir(const QString &uri, int vmaj, int vmin, QQ
         QString absoluteFilePath = typeLoader.absoluteFilePath(qmldirPath);
         if (!absoluteFilePath.isEmpty()) {
             QString url;
-            QString absolutePath = absoluteFilePath.left(absoluteFilePath.lastIndexOf(Slash)+1);
+            const QStringRef absolutePath = absoluteFilePath.leftRef(absoluteFilePath.lastIndexOf(Slash) + 1);
             if (absolutePath.at(0) == Colon)
                 url = QLatin1String("qrc://") + absolutePath.mid(1);
             else
-                url = QUrl::fromLocalFile(absolutePath).toString();
+                url = QUrl::fromLocalFile(absolutePath.toString()).toString();
 
             QQmlImportDatabase::QmldirCache *cache = new QQmlImportDatabase::QmldirCache;
             cache->versionMajor = vmaj;