Implement QTableWidget/QListWidget::mimeData()

For some reasons lost in history, those methods simply ignore
the list of items passed to them, and always return NULL.
Of course, that's totally broken. Fix that by doing the same thing
that the respective (hidden) models did when calling mimeData().

Surprisingly enough, QTreeWidget has a proper implementation.

Task-number: QTBUG-25900
Change-Id: I99ca7b4d4f87f096fd9ff0b0cb4e58282aa9c26e
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: David Faure <david.faure@kdab.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/src/widgets/itemviews/qlistwidget.cpp b/src/widgets/itemviews/qlistwidget.cpp
index 51561ac23b..aae75e5651 100644
--- a/src/widgets/itemviews/qlistwidget.cpp
+++ b/src/widgets/itemviews/qlistwidget.cpp
@@ -1783,9 +1783,24 @@ QStringList QListWidget::mimeTypes() const
     If the list of items is empty, 0 is returned instead of a serialized empty
     list.
 */
-QMimeData *QListWidget::mimeData(const QList<QListWidgetItem*>) const
+QMimeData *QListWidget::mimeData(const QList<QListWidgetItem*> items) const
 {
-    return d_func()->listModel()->internalMimeData();
+    Q_D(const QListWidget);
+
+    QModelIndexList &cachedIndexes = d->listModel()->cachedIndexes;
+
+    // if non empty, it's called from the model's own mimeData
+    if (cachedIndexes.isEmpty()) {
+        foreach (QListWidgetItem *item, items)
+            cachedIndexes << indexFromItem(item);
+
+        QMimeData *result = d->listModel()->internalMimeData();
+
+        cachedIndexes.clear();
+        return result;
+    }
+
+    return d->listModel()->internalMimeData();
 }
 
 #ifndef QT_NO_DRAGANDDROP