QQuickTableView: sync model and delegate when ready to do so

Doing (silly) things in the delegate, like:

    Component.onCompleted: TableView.view.delegate = null

will lead to a crash. The same if you change the model.
The reason is that you end up changing the model
while e.g a row is half-way loaded. Information needed for
building the row, like model size, will then be invalid.

To protect against this, we insert a "sync" phase to the
code that takes any such changes into effect at a time
when we know it's safe to do so.

Change-Id: I85a992dfc0e04ec6635b10c9768a8ddc140e09da
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/quick/items/qquicktableview_p_p.h b/src/quick/items/qquicktableview_p_p.h
index 9ff2b2e10b..6bf3de76df 100644
--- a/src/quick/items/qquicktableview_p_p.h
+++ b/src/quick/items/qquicktableview_p_p.h
@@ -206,6 +206,11 @@ public:
     QPointer<QQmlTableInstanceModel> tableModel = nullptr;
     QVariant modelVariant;
 
+    // When the applications assignes a new model or delegate to the view, we keep them
+    // around until we're ready to take them into use (syncWithPendingChanges).
+    QVariant assignedModel = QVariant(int(0));
+    QQmlComponent *assignedDelegate = nullptr;
+
     // loadedTable describes the table cells that are currently loaded (from top left
     // row/column to bottom right row/column). loadedTableOuterRect describes the actual
     // pixels that those cells cover, and is matched agains the viewport to determine when
@@ -332,6 +337,11 @@ public:
     void itemReusedCallback(int modelIndex, QObject *object);
     void modelUpdated(const QQmlChangeSet &changeSet, bool reset);
 
+    inline void syncWithPendingChanges();
+    inline void syncDelegate();
+    inline void syncModel();
+    inline void syncRebuildOptions();
+
     void connectToModel();
     void disconnectFromModel();