Function existentWidgetForDockWidget

kdevplatform/sublime/idealcontroller.cpp:119–137

* Return a widget that used to be and can again become a dock widget's widget * (@p viewWidget itself or its QMainWindow parent). * * @param mainWindow the main window ancestor of @p viewWidget * @param viewWidget non-null disowned tool view widget */

 * @param viewWidget non-null disowned tool view widget
 */
[[nodiscard]] QWidget* existentWidgetForDockWidget(const Sublime::MainWindow& mainWindow, QWidget* viewWidget)
{
    Q_ASSERT(viewWidget);

    // The previous dock widget (grand)parent of the disowned view widget must have been destroyed by now, and
    // the view widget itself must have been saved from destruction by setting its (grand)parent to the main window.
    // If not, the caller of this function would be stealing the view widget from its current (grand)parent dock widget.

    auto* const viewParent = viewWidget->parentWidget();
    Q_ASSERT(viewParent);
    if (viewParent == &mainWindow) {
        return viewWidget;
    }

    // a tool view widget with a toolbar lives in a QMainWindow that lives in a dock widget
    Q_ASSERT(qobject_cast<QMainWindow*>(viewParent));
    Q_ASSERT(viewParent->parentWidget() == &mainWindow);
    return viewParent;
}

struct DockWidgetInfo
{