Don't parent (QObject) delegate items to views.

This keeps object ownership within the context the items were created
in and simplifies lifetime management as the VisualDataModel has sole
license to delete objects and doesn't have to keep guards against a
view and all it's children being deleted.

Delegates are still reparented in the item heirarchy.

Change-Id: Ife5afdfe294a5a8ca1ca3638a086f72452e4915c
Reviewed-by: Martin Jones <martin.jones@nokia.com>

6 files changed, 25 insertions, 57 deletions

diff --git a/src/quick/items/qquickitemview.cpp b/src/quick/items/qquickitemview.cpp
index 88a8a30b0c..da661af689 100644
--- a/src/quick/items/qquickitemview.cpp
+++ b/src/quick/items/qquickitemview.cpp
@@ -2181,7 +2181,6 @@ FxViewItem *QQuickItemViewPrivate::createItem(int modelIndex, bool asynchronous)
 
     if (QQuickItem *item = model->item(modelIndex, asynchronous)) {
         item->setParentItem(q->contentItem());
-        QQml_setParent_noEvent(item, q->contentItem());
         requestedIndex = -1;
         FxViewItem *viewItem = requestedItem;
         if (!viewItem)
@@ -2228,7 +2227,6 @@ void QQuickItemView::initItem(int index, QQuickItem *item)
         if (d->requestedAsync)
             item->setVisible(false);
         item->setParentItem(contentItem());
-        QQml_setParent_noEvent(item, contentItem());
         d->requestedItem = d->newViewItem(index, item);
     }
 }
diff --git a/src/quick/items/qquickpathview.cpp b/src/quick/items/qquickpathview.cpp
index fa281cb245..1561dbc00c 100644
--- a/src/quick/items/qquickpathview.cpp
+++ b/src/quick/items/qquickpathview.cpp
@@ -154,7 +154,6 @@ QQuickItem *QQuickPathViewPrivate::getItem(int modelIndex, qreal z, bool onPath)
     inRequest = true;
     QQuickItem *item = model->item(modelIndex, false);
     if (item) {
-        QQml_setParent_noEvent(item, q);
         item->setParentItem(q);
         requestedIndex = -1;
         qPathViewAttachedType = attType;
@@ -181,7 +180,6 @@ void QQuickPathView::createdItem(int index, QQuickItem *item)
             att->setOnPath(false);
         }
         item->setParentItem(this);
-        QQml_setParent_noEvent(item, this);
         d->updateItem(item, index < d->firstIndex ? 0.0 : 1.0);
     } else {
         d->requestedIndex = -1;
diff --git a/src/quick/items/qquickrepeater.cpp b/src/quick/items/qquickrepeater.cpp
index ec8dc9d231..db58fba00c 100644
--- a/src/quick/items/qquickrepeater.cpp
+++ b/src/quick/items/qquickrepeater.cpp
@@ -386,7 +386,6 @@ void QQuickRepeaterPrivate::createItems()
                 break;
             }
             deletables[ii] = item;
-            QQml_setParent_noEvent(item, q->parentItem());
             item->setParentItem(q->parentItem());
             if (ii > 0 && deletables.at(ii-1)) {
                 item->stackAfter(deletables.at(ii-1));
@@ -415,7 +414,6 @@ void QQuickRepeater::createdItem(int, QQuickItem *)
 
 void QQuickRepeater::initItem(int, QQuickItem *item)
 {
-    QQml_setParent_noEvent(item, parentItem());
     item->setParentItem(parentItem());
 }
 
diff --git a/src/quick/items/qquickvisualdatamodel.cpp b/src/quick/items/qquickvisualdatamodel.cpp
index dfbf3a37ab..4d295b3203 100644
--- a/src/quick/items/qquickvisualdatamodel.cpp
+++ b/src/quick/items/qquickvisualdatamodel.cpp
@@ -194,12 +194,10 @@ QQuickVisualDataModel::~QQuickVisualDataModel()
     Q_D(QQuickVisualDataModel);
 
     foreach (QQuickVisualDataModelItem *cacheItem, d->m_cache) {
-        if (QObject *object = cacheItem->object()) {
-            // Clear the guard before deleting the object so it doesn't decrement scriptRef and
-            // potentially delete the cacheItem itself.
-            cacheItem->setObject(0);
-            delete object;
+        if (cacheItem->object) {
+            delete cacheItem->object;
 
+            cacheItem->object = 0;
             cacheItem->contextData->destroy();
             cacheItem->contextData = 0;
             cacheItem->scriptRef -= 1;
@@ -517,8 +515,8 @@ void QQuickVisualDataModel::cancel(int index)
             d->releaseIncubator(cacheItem->incubationTask);
             cacheItem->incubationTask = 0;
         }
-        if (cacheItem->object() && !cacheItem->isObjectReferenced()) {
-            QObject *object = cacheItem->object();
+        if (cacheItem->object && !cacheItem->isObjectReferenced()) {
+            QObject *object = cacheItem->object;
             cacheItem->destroyObject();
             if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(object))
                 d->emitDestroyingPackage(package);
@@ -784,9 +782,9 @@ void QQuickVisualDataModelPrivate::incubatorStatusChanged(QVDMIncubationTask *in
     if (status == QQmlIncubator::Ready) {
         incubationTask->incubating = 0;
         releaseIncubator(incubationTask);
-        if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(cacheItem->object()))
+        if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(cacheItem->object))
             emitCreatedPackage(cacheItem, package);
-        else if (QQuickItem *item = qobject_cast<QQuickItem *>(cacheItem->object()))
+        else if (QQuickItem *item = qobject_cast<QQuickItem *>(cacheItem->object))
             emitCreatedItem(cacheItem, item);
     } else if (status == QQmlIncubator::Error) {
         cacheItem->scriptRef -= 1;
@@ -814,11 +812,11 @@ void QVDMIncubationTask::setInitialState(QObject *o)
 void QQuickVisualDataModelPrivate::setInitialState(QVDMIncubationTask *incubationTask, QObject *o)
 {
     QQuickVisualDataModelItem *cacheItem = incubationTask->incubating;
-    cacheItem->setObject(o);
+    cacheItem->object = o;
 
-    if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(cacheItem->object()))
+    if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(cacheItem->object))
         emitInitPackage(cacheItem, package);
-    else if (QQuickItem *item = qmlobject_cast<QQuickItem *>(cacheItem->object()))
+    else if (QQuickItem *item = qmlobject_cast<QQuickItem *>(cacheItem->object))
         emitInitItem(cacheItem, item);
 }
 
@@ -854,7 +852,7 @@ QObject *QQuickVisualDataModelPrivate::object(Compositor::Group group, int index
             // previously requested async - now needed immediately
             cacheItem->incubationTask->forceCompletion();
         }
-    } else if (!cacheItem->object()) {
+    } else if (!cacheItem->object) {
         QQmlContext *creationContext = m_delegate->creationContext();
 
         cacheItem->scriptRef += 1;
@@ -886,9 +884,9 @@ QObject *QQuickVisualDataModelPrivate::object(Compositor::Group group, int index
 
     if (index == m_compositor.count(group) - 1 && m_adaptorModel.canFetchMore())
         QCoreApplication::postEvent(q, new QEvent(QEvent::UpdateRequest));
-    if (cacheItem->object() && reference)
+    if (cacheItem->object && reference)
         cacheItem->referenceObject();
-    return cacheItem->object();
+    return cacheItem->object;
 }
 
 /*
@@ -1157,14 +1155,13 @@ void QQuickVisualDataModelPrivate::itemsRemoved(
         } else {
             for (; cacheIndex < remove.cacheIndex + remove.count - removedCache; ++cacheIndex) {
                 QQuickVisualDataModelItem *cacheItem = m_cache.at(cacheIndex);
-                if (remove.inGroup(Compositor::Persisted) && cacheItem->objectRef == 0 && cacheItem->object()) {
-                    QObject *object = cacheItem->object();
+                if (remove.inGroup(Compositor::Persisted) && cacheItem->objectRef == 0 && cacheItem->object) {
+                    QObject *object = cacheItem->object;
                     cacheItem->destroyObject();
                     if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(object))
                         emitDestroyingPackage(package);
                     else if (QQuickItem *item = qmlobject_cast<QQuickItem *>(object))
                         emitDestroyingItem(item);
-                    cacheItem->setObject(0);
                     cacheItem->scriptRef -= 1;
                 }
                 if (!cacheItem->isReferenced()) {
@@ -1321,7 +1318,7 @@ void QQuickVisualDataModelPrivate::emitChanges()
         QQuickVisualDataGroupPrivate::get(m_groups[i])->emitModelUpdated(reset);
 
     foreach (QQuickVisualDataModelItem *cacheItem, m_cache) {
-        if (cacheItem->object() && cacheItem->attached)
+        if (cacheItem->attached)
             cacheItem->attached->emitChanges();
     }
 }
@@ -1406,7 +1403,7 @@ void QQuickVisualDataModel::_q_layoutChanged()
 QQuickVisualDataModelAttached *QQuickVisualDataModel::qmlAttachedProperties(QObject *obj)
 {
     if (QQuickVisualDataModelItem *cacheItem = QQuickVisualDataModelItem::dataForObject(obj)) {
-        if (cacheItem->object() == obj) { // Don't create attached item for child objects.
+        if (cacheItem->object == obj) { // Don't create attached item for child objects.
             cacheItem->attached = new QQuickVisualDataModelAttached(cacheItem, obj);
             return cacheItem->attached;
         }
@@ -1678,6 +1675,7 @@ QQuickVisualDataModelItem::QQuickVisualDataModelItem(
     : QV8ObjectResource(metaType->v8Engine)
     , metaType(metaType)
     , contextData(0)
+    , object(0)
     , attached(0)
     , incubationTask(0)
     , objectRef(0)
@@ -1692,7 +1690,7 @@ QQuickVisualDataModelItem::~QQuickVisualDataModelItem()
 {
     Q_ASSERT(scriptRef == 0);
     Q_ASSERT(objectRef == 0);
-    Q_ASSERT(!object());
+    Q_ASSERT(!object);
     Q_ASSERT(indexHandle.IsEmpty());
     Q_ASSERT(modelHandle.IsEmpty());
 
@@ -1749,18 +1747,15 @@ void QQuickVisualDataModelItem::incubateObject(
 
 void QQuickVisualDataModelItem::destroyObject()
 {
-    QObject * const obj = object();
-    setObject(0);
-
-    Q_ASSERT(obj);
+    Q_ASSERT(object);
     Q_ASSERT(contextData);
 
-    QObjectPrivate *p = QObjectPrivate::get(obj);
+    QObjectPrivate *p = QObjectPrivate::get(object);
     Q_ASSERT(p->declarativeData);
     QQmlData *data = static_cast<QQmlData*>(p->declarativeData);
     if (data->ownContext && data->context)
         data->context->clearContext();
-    obj->deleteLater();
+    object->deleteLater();
 
     if (attached) {
         attached->m_cacheItem = 0;
@@ -1769,6 +1764,7 @@ void QQuickVisualDataModelItem::destroyObject()
 
     contextData->destroy();
     contextData = 0;
+    object = 0;
 }
 
 QQuickVisualDataModelItem *QQuickVisualDataModelItem::dataForObject(QObject *object)
@@ -1786,25 +1782,6 @@ QQuickVisualDataModelItem *QQuickVisualDataModelItem::dataForObject(QObject *obj
     return 0;
 }
 
-void QQuickVisualDataModelItem::objectDestroyed(QObject *)
-{
-    const bool contextValid = contextData->isValid();
-    contextData->destroy();
-    contextData = 0;
-    attached = 0;
-    objectRef = 0;
-
-    if (contextValid) {
-        Dispose();
-    } else {
-        // The parent context was invalidated, meaning the visual data model is about to be
-        // destroyed.  So we'll just decrement the script ref here and let the vdm destructor
-        // destroy the object if necessary, rather than Dispose of the object and unnecessarily
-        // remove each item from the soon to be destroyed cache list individually.
-        scriptRef -= 1;
-    }
-}
-
 //---------------------------------------------------------------------------
 
 QQuickVisualDataModelAttachedMetaObject::QQuickVisualDataModelAttachedMetaObject(
@@ -2841,7 +2818,6 @@ QQuickVisualModel::ReleaseFlags QQuickVisualPartsModel::release(QQuickItem *item
     QHash<QObject *, QQuickPackage *>::iterator it = m_packaged.find(item);
     if (it != m_packaged.end()) {
         QQuickPackage *package = *it;
-        QQml_setParent_noEvent(item, package);
         QQuickVisualDataModelPrivate *model = QQuickVisualDataModelPrivate::get(m_model);
         flags = model->release(package);
         m_packaged.erase(it);
@@ -2893,7 +2869,6 @@ void QQuickVisualPartsModel::destroyingPackage(QQuickPackage *package)
         Q_ASSERT(!m_packaged.contains(item));
         emit destroyingItem(item);
         item->setParentItem(0);
-        QQml_setParent_noEvent(item, package);
     }
 }
 
diff --git a/src/quick/items/qquickvisualdatamodel_p_p.h b/src/quick/items/qquickvisualdatamodel_p_p.h
index e2887e73f7..ad5aa5ed62 100644
--- a/src/quick/items/qquickvisualdatamodel_p_p.h
+++ b/src/quick/items/qquickvisualdatamodel_p_p.h
@@ -103,7 +103,7 @@ public:
 class QQuickVisualAdaptorModel;
 class QVDMIncubationTask;
 
-class QQuickVisualDataModelItem : public QObject, public QV8ObjectResource, public QQmlGuard<QObject>
+class QQuickVisualDataModelItem : public QObject, public QV8ObjectResource
 {
     Q_OBJECT
     Q_PROPERTY(int index READ modelIndex NOTIFY modelIndexChanged)
@@ -146,6 +146,7 @@ public:
 
     QQuickVisualDataModelItemMetaType * const metaType;
     QQmlContextData *contextData;
+    QObject *object;
     QQuickVisualDataModelAttached *attached;
     QVDMIncubationTask *incubationTask;
     v8::Persistent<v8::Object> indexHandle;
diff --git a/src/quick/items/qquickvisualitemmodel.cpp b/src/quick/items/qquickvisualitemmodel.cpp
index df274e1d42..1cefcb4ce9 100644
--- a/src/quick/items/qquickvisualitemmodel.cpp
+++ b/src/quick/items/qquickvisualitemmodel.cpp
@@ -65,7 +65,6 @@ public:
     QQuickVisualItemModelPrivate() : QObjectPrivate() {}
 
     static void children_append(QQmlListProperty<QQuickItem> *prop, QQuickItem *item) {
-        QQml_setParent_noEvent(item, prop->object);
         static_cast<QQuickVisualItemModelPrivate *>(prop->data)->children.append(Item(item));
         static_cast<QQuickVisualItemModelPrivate *>(prop->data)->itemAppended();
         static_cast<QQuickVisualItemModelPrivate *>(prop->data)->emitChildrenChanged();
@@ -206,7 +205,6 @@ QQuickVisualModel::ReleaseFlags QQuickVisualItemModel::release(QQuickItem *item)
         if (d->children[idx].deref()) {
             // XXX todo - the original did item->scene()->removeItem().  Why?
             item->setParentItem(0);
-            QQml_setParent_noEvent(item, this);
         }
     }
     return 0;