ADS: Fix repeatedly dropping in same area crash

6c687d28def5c24f3eeb67c9e13d5cfab40cebd0
1c2383f8eb94bc8570e554efa5f842a8ab1461ea

Task-number: QDS-1751
Change-Id: I933b1f53da8ce423cd5d38ff2863f58606006596
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/libs/advanceddockingsystem/dockcontainerwidget.cpp

@@ -595,7 +595,7 @@ namespace ADS
     {
         DockWidget *droppedDockWidget = qobject_cast<DockWidget *>(widget);
         DockAreaWidget *droppedDockArea = qobject_cast<DockAreaWidget *>(widget);
-        DockAreaWidget *newDockArea;
+        DockAreaWidget *newDockArea = nullptr;
 
         if (droppedDockWidget) {
             newDockArea = new DockAreaWidget(m_dockManager, q);
@@ -605,6 +605,18 @@ namespace ADS
             }
             newDockArea->addDockWidget(droppedDockWidget);
         } else {
+            // We check, if we insert the dropped widget into the same place that
+            // it already has and do nothing, if it is the same place. It would
+            // also work without this check, but it looks nicer with the check
+            // because there will be no layout updates
+            auto splitter = internal::findParent<DockSplitter*>(droppedDockArea);
+            auto insertParam = internal::dockAreaInsertParameters(area);
+            if (splitter == m_rootSplitter && insertParam.orientation() == splitter->orientation()) {
+                if (insertParam.append() && splitter->lastWidget() == droppedDockArea)
+                    return;
+                else if (!insertParam.append() && splitter->firstWidget() == droppedDockArea)
+                    return;
+            }
             droppedDockArea->dockContainer()->removeDockArea(droppedDockArea);
             newDockArea = droppedDockArea;
         }
@@ -1217,36 +1229,13 @@ namespace ADS
         }
     }
 
-    void DockContainerWidget::dropWidget(QWidget *widget, const QPoint &targetPosition)
+    void DockContainerWidget::dropWidget(QWidget *widget, DockWidgetArea dropArea, DockAreaWidget *targetAreaWidget)
     {
-        qCInfo(adsLog) << Q_FUNC_INFO;
         DockWidget *singleDockWidget = topLevelDockWidget();
-        DockAreaWidget *dockArea = dockAreaAt(targetPosition);
-        auto dropArea = InvalidDockWidgetArea;
-        auto containerDropArea = d->m_dockManager->containerOverlay()->dropAreaUnderCursor();
-
-        if (dockArea) {
-            auto dropOverlay = d->m_dockManager->dockAreaOverlay();
-            dropOverlay->setAllowedAreas(dockArea->allowedAreas());
-            dropArea = dropOverlay->showOverlay(dockArea);
-            if (containerDropArea != InvalidDockWidgetArea && containerDropArea != dropArea) {
-                dropArea = InvalidDockWidgetArea;
-            }
-
-            if (dropArea != InvalidDockWidgetArea) {
-                qCInfo(adsLog) << "Dock Area Drop Content: " << dropArea;
-                d->moveToNewSection(widget, dockArea, dropArea);
-            }
-        }
-
-        // mouse is over container
-        if (InvalidDockWidgetArea == dropArea) {
-            dropArea = containerDropArea;
-            qCInfo(adsLog) << "Container Drop Content: " << dropArea;
-            if (dropArea != InvalidDockWidgetArea) {
+        if (targetAreaWidget)
+            d->moveToNewSection(widget, targetAreaWidget, dropArea);
+        else
             d->moveToContainer(widget, dropArea);
-            }
-        }
 
         // If there was a top level widget before the drop, then it is not top
         // level widget anymore

src/libs/advanceddockingsystem/dockcontainerwidget.h

@@ -104,9 +104,13 @@ protected:
     void dropFloatingWidget(FloatingDockContainer *floatingWidget, const QPoint &targetPos);
 
     /**
-     * Drop a dock area or a dock widget given in widget parameter
+     * Drop a dock area or a dock widget given in widget parameter.
+     * If the TargetAreaWidget is a nullptr, then the DropArea indicates
+     * the drop area for the container. If the given TargetAreaWidget is not
+     * a nullptr, then the DropArea indicates the drop area in the given
+     * TargetAreaWidget
      */
-    void dropWidget(QWidget *widget, const QPoint &targetPos);
+    void dropWidget(QWidget *widget, DockWidgetArea dropArea, DockAreaWidget *targetAreaWidget);
 
     /**
      * Adds the given dock area to this container widget

src/libs/advanceddockingsystem/dockoverlay.cpp

@@ -399,6 +399,14 @@ namespace ADS {
         return result;
     }
 
+    DockWidgetArea DockOverlay::visibleDropAreaUnderCursor() const
+    {
+        if (isHidden() || !d->m_dropPreviewEnabled)
+            return InvalidDockWidgetArea;
+        else
+            return dropAreaUnderCursor();
+    }
+
     DockWidgetArea DockOverlay::showOverlay(QWidget *target)
     {
         if (d->m_targetWidget == target) {

src/libs/advanceddockingsystem/dockoverlay.h

@@ -93,6 +93,13 @@ public:
      */
     DockWidgetArea dropAreaUnderCursor() const;
 
+    /**
+     * This function returns the same like dropAreaUnderCursor() if this
+     * overlay is not hidden and if drop preview is enabled and returns
+     * InvalidDockWidgetArea if it is hidden or drop preview is disabled.
+     */
+    DockWidgetArea visibleDropAreaUnderCursor() const;
+
     /**
      * Show the drop overly for the given target widget
      */

src/libs/advanceddockingsystem/docksplitter.cpp

@@ -89,4 +89,14 @@ namespace ADS
         return false;
     }
 
+    QWidget *DockSplitter::firstWidget() const
+    {
+        return (count() > 0) ? widget(0) : nullptr;
+    }
+
+    QWidget *DockSplitter::lastWidget() const
+    {
+        return (count() > 0) ? widget(count() - 1) : nullptr;
+    }
+
 } // namespace ADS

src/libs/advanceddockingsystem/docksplitter.h

@@ -67,6 +67,16 @@ public:
      * Returns true, if any of the internal widgets is visible
      */
     bool hasVisibleContent() const;
+
+    /**
+     * Returns first widget or nullptr if splitter is empty
+     */
+    QWidget *firstWidget() const;
+
+    /**
+     * Returns last widget of nullptr is splitter is empty
+     */
+    QWidget *lastWidget() const;
 }; // class DockSplitter
 
 } // namespace ADS

src/libs/advanceddockingsystem/floatingdragpreview.cpp

@@ -262,12 +262,14 @@ namespace ADS
     void FloatingDragPreview::finishDragging()
     {
         qCInfo(adsLog) << Q_FUNC_INFO;
-        auto dockDropArea = d->m_dockManager->dockAreaOverlay()->dropAreaUnderCursor();
-        auto containerDropArea = d->m_dockManager->containerOverlay()->dropAreaUnderCursor();
-        bool dropPossible = (dockDropArea != InvalidDockWidgetArea)
-                            || (containerDropArea != InvalidDockWidgetArea);
-        if (d->m_dropContainer && dropPossible) {
-            d->m_dropContainer->dropWidget(d->m_content, QCursor::pos());
+        auto dockDropArea = d->m_dockManager->dockAreaOverlay()->visibleDropAreaUnderCursor();
+        auto containerDropArea = d->m_dockManager->containerOverlay()->visibleDropAreaUnderCursor();
+        if (d->m_dropContainer && (dockDropArea != InvalidDockWidgetArea)) {
+            d->m_dropContainer->dropWidget(d->m_content,
+                                           dockDropArea,
+                                           d->m_dropContainer->dockAreaAt(QCursor::pos()));
+        } else if (d->m_dropContainer && (containerDropArea != InvalidDockWidgetArea)) {
+            d->m_dropContainer->dropWidget(d->m_content, containerDropArea, nullptr);
         } else {
             DockWidget *dockWidget = qobject_cast<DockWidget *>(d->m_content);
             FloatingDockContainer *floatingWidget = nullptr;