Designer: Extend container extension.

Make it possible to disable adding/removing pages by
adding respective bool virtual functions.

Useful for implementing containers with fixed, single
children like QScrollArea, QDockWidget, which require
a container extension to work properly in Qt Designer.
Previously, the problem was that the add/remove
page context menu actions were enabled for them,
leading to crashes und undesired behaviour.

See e00b8105bfcf3d4e36275dea6355705ec5fdbc40 in qtbase.

Reviewed-by: Jarek Kobus <jaroslaw.kobus@nokia.com>

3 files changed, 23 insertions, 14 deletions

diff --git a/src/designer/src/components/formeditor/default_container.h b/src/designer/src/components/formeditor/default_container.h
index 753f39794..43e2700fe 100644
--- a/src/designer/src/components/formeditor/default_container.h
+++ b/src/designer/src/components/formeditor/default_container.h
@@ -139,6 +139,9 @@ public:
     virtual void insertWidget(int index, QWidget *widget);
     virtual void remove(int /*index*/) {}
 
+    virtual bool canAddWidget() const { return false; }
+    virtual bool canRemove(int) const { return false; }
+
 private:
     const bool m_active;
     Container *m_container;
diff --git a/src/designer/src/components/taskmenu/containerwidget_taskmenu.cpp b/src/designer/src/components/taskmenu/containerwidget_taskmenu.cpp
index 244ea00ff..9b6265f27 100644
--- a/src/designer/src/components/taskmenu/containerwidget_taskmenu.cpp
+++ b/src/designer/src/components/taskmenu/containerwidget_taskmenu.cpp
@@ -76,6 +76,8 @@ ContainerWidgetTaskMenu::ContainerWidgetTaskMenu(QWidget *widget, ContainerType
     m_pagePromotionTaskMenu(new PromotionTaskMenu(0, PromotionTaskMenu::ModeSingleWidget, this)),
     m_pageMenuAction(new QAction(this)),
     m_pageMenu(new QMenu),
+    m_actionInsertPageAfter(new QAction(this)),
+    m_actionInsertPage(0),
     m_actionDeletePage(new QAction(tr("Delete"), this))
 {
     Q_ASSERT(m_core);
@@ -83,8 +85,7 @@ ContainerWidgetTaskMenu::ContainerWidgetTaskMenu(QWidget *widget, ContainerType
 
     connect(m_actionDeletePage, SIGNAL(triggered()), this, SLOT(removeCurrentPage()));
 
-    QAction *actionInsertPageAfter = new QAction(this);
-    connect(actionInsertPageAfter, SIGNAL(triggered()), this, SLOT(addPageAfter()));
+    connect(m_actionInsertPageAfter, SIGNAL(triggered()), this, SLOT(addPageAfter()));
     // Empty Per-Page submenu, deletion and promotion. Updated on demand due to promotion state
     switch (m_type) {
     case WizardContainer:
@@ -104,20 +105,20 @@ ContainerWidgetTaskMenu::ContainerWidgetTaskMenu(QWidget *widget, ContainerType
         QAction *insertMenuAction = new QAction(tr("Insert"), this);
         QMenu *insertMenu = new QMenu;
         // before
-        QAction *actionInsertPage = new QAction(tr("Insert Page Before Current Page"), this);
-        connect(actionInsertPage, SIGNAL(triggered()), this, SLOT(addPage()));
-        insertMenu->addAction(actionInsertPage);
+        m_actionInsertPage = new QAction(tr("Insert Page Before Current Page"), this);
+        connect(m_actionInsertPage, SIGNAL(triggered()), this, SLOT(addPage()));
+        insertMenu->addAction(m_actionInsertPage);
         // after
-        actionInsertPageAfter->setText(tr("Insert Page After Current Page"));
-        insertMenu->addAction(actionInsertPageAfter);
+        m_actionInsertPageAfter->setText(tr("Insert Page After Current Page"));
+        insertMenu->addAction(m_actionInsertPageAfter);
 
         insertMenuAction->setMenu(insertMenu);
         m_taskActions.append(insertMenuAction);
     }
         break;
     case MdiContainer: // No concept of order
-        actionInsertPageAfter->setText(tr("Add Subwindow"));
-        m_taskActions.append(actionInsertPageAfter);
+        m_actionInsertPageAfter->setText(tr("Add Subwindow"));
+        m_taskActions.append(m_actionInsertPageAfter);
         break;
     }
 }
@@ -162,14 +163,19 @@ QString ContainerWidgetTaskMenu::pageMenuText(ContainerType ct, int index, int c
 
 QList<QAction*> ContainerWidgetTaskMenu::taskActions() const
 {
+    const QDesignerContainerExtension *ce = containerExtension();
+    const int index = ce->currentIndex();
+
     QList<QAction*> actions = QDesignerTaskMenu::taskActions();
     actions += m_taskActions;
     // Update the page submenu, deletion and promotion. Updated on demand due to promotion state.
     m_pageMenu->clear();
+    const bool canAddWidget = ce->canAddWidget();
+    if (m_actionInsertPage)
+        m_actionInsertPage->setEnabled(canAddWidget);
+    m_actionInsertPageAfter->setEnabled(canAddWidget);
     m_pageMenu->addAction(m_actionDeletePage);
-    m_actionDeletePage->setEnabled(canDeletePage());
-    const QDesignerContainerExtension *ce = containerExtension();
-    const int index = ce->currentIndex();
+    m_actionDeletePage->setEnabled(index >= 0 && ce->canRemove(index) && canDeletePage());
     m_pageMenuAction->setText(pageMenuText(m_type, index, ce->count()));
     if (index != -1) { // Has a page
         m_pageMenuAction->setEnabled(true);
@@ -319,8 +325,6 @@ QObject *ContainerWidgetTaskMenuFactory::createExtension(QObject *object, const
     if (qobject_cast<QStackedWidget*>(widget)
             || qobject_cast<QToolBox*>(widget)
             || qobject_cast<QTabWidget*>(widget)
-            || qobject_cast<QDesignerDockWidget*>(widget)
-            || qobject_cast<QScrollArea*>(widget)
             || qobject_cast<QMainWindow*>(widget)) {
         // Are we using Designer's own container extensions and task menus or did
         // someone provide an extra one with an addpage method, for example for a QScrollArea?
diff --git a/src/designer/src/components/taskmenu/containerwidget_taskmenu.h b/src/designer/src/components/taskmenu/containerwidget_taskmenu.h
index 6c5f1d481..3e6b35de5 100644
--- a/src/designer/src/components/taskmenu/containerwidget_taskmenu.h
+++ b/src/designer/src/components/taskmenu/containerwidget_taskmenu.h
@@ -100,6 +100,8 @@ private:
     QAction *m_pageMenuAction;
     QMenu *m_pageMenu;
     QList<QAction*> m_taskActions;
+    QAction *m_actionInsertPageAfter;
+    QAction *m_actionInsertPage;
     QAction *m_actionDeletePage;
 };