Don't leak components in QQuickLoader

Only create source component in loadFromSource if it does not already exist.
Previously toggling the active status when loading from source would create
a new source component every time active became true.

[ChangeLog][QtQuick][Loader] Don't leak components when changing source url.

Change-Id: I1e4cfd5613e3851fcb4f3f55e78981f7c070cc77
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

2 files changed, 59 insertions, 2 deletions

diff --git a/src/quick/items/qquickloader.cpp b/src/quick/items/qquickloader.cpp
index ea6a63559a..b5ae41daef 100644
--- a/src/quick/items/qquickloader.cpp
+++ b/src/quick/items/qquickloader.cpp
@@ -112,6 +112,8 @@ void QQuickLoaderPrivate::clear()
                 q, SIGNAL(progressChanged()));
         component->deleteLater();
         component = nullptr;
+    } else if (component) {
+        component = nullptr;
     }
     componentStrongReference.clear();
     source = QUrl();
@@ -438,7 +440,8 @@ void QQuickLoader::loadFromSource()
 
     if (isComponentComplete()) {
         QQmlComponent::CompilationMode mode = d->asynchronous ? QQmlComponent::Asynchronous : QQmlComponent::PreferSynchronous;
-        d->component = new QQmlComponent(qmlEngine(this), d->source, mode, this);
+        if (!d->component)
+            d->component = new QQmlComponent(qmlEngine(this), d->source, mode, this);
         d->load();
     }
 }
@@ -828,7 +831,8 @@ void QQuickLoader::componentComplete()
     if (active()) {
         if (d->loadingFromSource) {
             QQmlComponent::CompilationMode mode = d->asynchronous ? QQmlComponent::Asynchronous : QQmlComponent::PreferSynchronous;
-            d->component = new QQmlComponent(qmlEngine(this), d->source, mode, this);
+            if (!d->component)
+                d->component = new QQmlComponent(qmlEngine(this), d->source, mode, this);
         }
         d->load();
     }
diff --git a/tests/auto/quick/qquickloader/tst_qquickloader.cpp b/tests/auto/quick/qquickloader/tst_qquickloader.cpp
index 7a176661e8..5c3729a8cd 100644
--- a/tests/auto/quick/qquickloader/tst_qquickloader.cpp
+++ b/tests/auto/quick/qquickloader/tst_qquickloader.cpp
@@ -126,6 +126,8 @@ private slots:
     void parentErrors();
 
     void rootContext();
+    void sourceURLKeepComponent();
+
 };
 
 Q_DECLARE_METATYPE(QList<QQmlError>)
@@ -1388,6 +1390,57 @@ void tst_QQuickLoader::rootContext()
     QCOMPARE(objectInRootContext.didIt, 2);
 }
 
+void tst_QQuickLoader::sourceURLKeepComponent()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine);
+    component.setData(QByteArray(
+                      "import QtQuick 2.0\n"
+                      " Loader { id: loader\n }"),
+                      dataDirectoryUrl());
+
+    QScopedPointer<QQuickLoader> loader(qobject_cast<QQuickLoader*>(component.create()));
+    loader->setSource(testFileUrl("/Rect120x60.qml"));
+
+    QVERIFY(loader);
+    QVERIFY(loader->item());
+    QVERIFY(loader->sourceComponent());
+    QCOMPARE(loader->progress(), 1.0);
+
+    const QPointer<QQmlComponent> sourceComponent =  loader->sourceComponent();
+
+    //Ensure toggling active status does not recreate component
+    loader->setActive(false);
+    QVERIFY(!loader->item());
+    QVERIFY(loader->sourceComponent());
+    QCOMPARE(sourceComponent.data(), loader->sourceComponent());
+
+    loader->setActive(true);
+    QVERIFY(loader->item());
+    QVERIFY(loader->sourceComponent());
+    QCOMPARE(sourceComponent.data(), loader->sourceComponent());
+
+    loader->setActive(false);
+    QVERIFY(!loader->item());
+    QVERIFY(loader->sourceComponent());
+    QCOMPARE(sourceComponent.data(), loader->sourceComponent());
+
+    //Ensure changing source url causes component to be recreated when inactive
+    loader->setSource(testFileUrl("/BlueRect.qml"));
+
+    loader->setActive(true);
+    QVERIFY(loader->item());
+    QVERIFY(loader->sourceComponent());
+
+    const QPointer<QQmlComponent> newSourceComponent =  loader->sourceComponent();
+    QVERIFY(sourceComponent.data() != newSourceComponent.data());
+
+    //Ensure changing source url causes component to be recreated when active
+    loader->setSource(testFileUrl("/Rect120x60.qml"));
+    QVERIFY(loader->sourceComponent() != newSourceComponent.data());
+
+}
+
 QTEST_MAIN(tst_QQuickLoader)
 
 #include "tst_qquickloader.moc"