From c37fbe0cbe0ccc0e5991df921aa0c7cf811a3baf Mon Sep 17 00:00:00 2001
From: Michael Brasser <michael.brasser@nokia.com>
Date: Tue, 16 Feb 2010 13:49:15 +1000
Subject: Fix crash in QmlMetaProperty that could occur when using value-type
 properties after the engine was deleted.

---
 src/declarative/qml/qmlengine_p.h                  |  1 +
 src/declarative/qml/qmlmetaproperty.cpp            |  7 +++--
 .../qmlmetaproperty/tst_qmlmetaproperty.cpp        | 30 ++++++++++++++++++++++
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/src/declarative/qml/qmlengine_p.h b/src/declarative/qml/qmlengine_p.h
index 87864b7..5586311 100644
--- a/src/declarative/qml/qmlengine_p.h
+++ b/src/declarative/qml/qmlengine_p.h
@@ -316,6 +316,7 @@ public:
     static QScriptEngine *getScriptEngine(QmlEngine *e) { return &e->d_func()->scriptEngine; }
     static QmlEngine *getEngine(QScriptEngine *e) { return static_cast<QmlScriptEngine*>(e)->p->q_func(); }
     static QmlEnginePrivate *get(QmlEngine *e) { return e->d_func(); }
+    static QmlEnginePrivate *get(QmlContext *c) { return (c && c->engine()) ? QmlEnginePrivate::get(c->engine()) : 0; }
     static QmlEnginePrivate *get(QScriptEngine *e) { return static_cast<QmlScriptEngine*>(e)->p; }
     static QmlEngine *get(QmlEnginePrivate *p) { return p->q_func(); }
     QmlContext *getContext(QScriptContext *);
diff --git a/src/declarative/qml/qmlmetaproperty.cpp b/src/declarative/qml/qmlmetaproperty.cpp
index d63261c..70f9ad3 100644
--- a/src/declarative/qml/qmlmetaproperty.cpp
+++ b/src/declarative/qml/qmlmetaproperty.cpp
@@ -276,7 +276,7 @@ const char *QmlMetaProperty::propertyTypeName() const
 {
     if (type() & ValueTypeProperty) {
 
-        QmlEnginePrivate *ep = d->context?QmlEnginePrivate::get(d->context->engine()):0;
+        QmlEnginePrivate *ep = QmlEnginePrivate::get(d->context);
         QmlValueType *valueType = 0;
         if (ep) valueType = ep->valueTypes[d->core.propType];
         else valueType = QmlValueTypeFactory::valueType(d->core.propType);
@@ -689,7 +689,7 @@ QVariant QmlMetaPropertyPrivate::readValueProperty()
 
     } else if(type & QmlMetaProperty::ValueTypeProperty) {
 
-        QmlEnginePrivate *ep = context?QmlEnginePrivate::get(context->engine()):0;
+        QmlEnginePrivate *ep = QmlEnginePrivate::get(context);
         QmlValueType *valueType = 0;
         if (ep) valueType = ep->valueTypes[core.propType];
         else valueType = QmlValueTypeFactory::valueType(core.propType);
@@ -762,8 +762,7 @@ bool QmlMetaPropertyPrivate::writeValueProperty(const QVariant &value,
     bool rv = false;
     uint type = q->type();
     if (type & QmlMetaProperty::ValueTypeProperty) {
-        QmlEnginePrivate *ep = 
-            context?static_cast<QmlEnginePrivate *>(QObjectPrivate::get(context->engine())):0;
+        QmlEnginePrivate *ep = QmlEnginePrivate::get(context);
 
         QmlValueType *writeBack = 0;
         if (ep) {
diff --git a/tests/auto/declarative/qmlmetaproperty/tst_qmlmetaproperty.cpp b/tests/auto/declarative/qmlmetaproperty/tst_qmlmetaproperty.cpp
index ec6b87f..5c8178f 100644
--- a/tests/auto/declarative/qmlmetaproperty/tst_qmlmetaproperty.cpp
+++ b/tests/auto/declarative/qmlmetaproperty/tst_qmlmetaproperty.cpp
@@ -122,6 +122,9 @@ private slots:
 
     //writeToReadOnly();
 
+    // Bugs
+    void crashOnValueProperty();
+
 private:
     QmlEngine engine;
 };
@@ -208,6 +211,9 @@ private:
     QUrl m_url;
 };
 
+QML_DECLARE_TYPE(PropertyObject);
+QML_DEFINE_TYPE(Test,1,0,PropertyObject,PropertyObject);
+
 void tst_qmlmetaproperty::qmlmetaproperty_object()
 {
     QObject object; // Has no default property
@@ -1118,6 +1124,30 @@ void tst_qmlmetaproperty::writeObjectToQmlList()
     QCOMPARE(container->qmlChildren()->at(1), object);
 }
 
+void tst_qmlmetaproperty::crashOnValueProperty()
+{
+    QmlEngine *engine = new QmlEngine;
+    QmlComponent component(engine);
+
+    component.setData("import Test 1.0\nPropertyObject { wrectProperty.x: 10 }", QUrl());
+    PropertyObject *obj = qobject_cast<PropertyObject*>(component.create());
+    QVERIFY(obj != 0);
+
+    QmlMetaProperty p = QmlMetaProperty::createProperty(obj, "wrectProperty.x", qmlContext(obj));
+    QCOMPARE(p.name(), QString("wrectProperty.x"));
+
+    QCOMPARE(p.read(), QVariant(10));
+
+    //don't crash once the engine is deleted
+    delete engine;
+    engine = 0;
+
+    QCOMPARE(p.propertyTypeName(), "int");
+    QCOMPARE(p.read(), QVariant(10));
+    p.write(QVariant(20));
+    QCOMPARE(p.read(), QVariant(20));
+}
+
 QTEST_MAIN(tst_qmlmetaproperty)
 
 #include "tst_qmlmetaproperty.moc"
-- 
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