Fix undefined behavior when closing layout designer

qgis · Feb 11, 2018 · db9db58 · db9db58
1 parent 779fe1a
commit db9db58
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Showing 5 changed files with 26 additions and 2 deletions.
diff --git a/python/gui/layout/qgslayoutview.sip.in b/python/gui/layout/qgslayoutview.sip.in
@@ -42,6 +42,8 @@ QgsLayoutView manages the layout interaction tools and mouse/key events.
 Constructor for QgsLayoutView.
 %End
 
+    ~QgsLayoutView();
+
     QgsLayout *currentLayout();
 %Docstring
 Returns the current layout associated with the view.
@@ -540,6 +542,12 @@ status bar.
 %Docstring
 Emitted when an ``item`` is "focused" in the view, i.e. it becomes the active
 item and should have its properties displayed in any designer windows.
+%End
+
+    void willBeDeleted();
+%Docstring
+Emitted in the destructor when the view is about to be deleted,
+but is still in a perfectly valid state.
 %End
 
   protected:

diff --git a/src/gui/layout/qgslayoutview.cpp b/src/gui/layout/qgslayoutview.cpp
@@ -68,6 +68,11 @@ QgsLayoutView::QgsLayoutView( QWidget *parent )
   connect( this, &QgsLayoutView::zoomLevelChanged, this, &QgsLayoutView::invalidateCachedRenders );
 }
 
+QgsLayoutView::~QgsLayoutView()
+{
+  emit willBeDeleted();
+}
+
 QgsLayout *QgsLayoutView::currentLayout()
 {
   return qobject_cast<QgsLayout *>( scene() );

diff --git a/src/gui/layout/qgslayoutview.h b/src/gui/layout/qgslayoutview.h
@@ -76,6 +76,8 @@ class GUI_EXPORT QgsLayoutView: public QGraphicsView
      */
     QgsLayoutView( QWidget *parent SIP_TRANSFERTHIS = nullptr );
 
+    ~QgsLayoutView();
+
     /**
      * Returns the current layout associated with the view.
      * \see setCurrentLayout()
@@ -515,6 +517,12 @@ class GUI_EXPORT QgsLayoutView: public QGraphicsView
      */
     void itemFocused( QgsLayoutItem *item );
 
+    /**
+     * Emitted in the destructor when the view is about to be deleted,
+     * but is still in a perfectly valid state.
+     */
+    void willBeDeleted();
+
   protected:
     void mousePressEvent( QMouseEvent *event ) override;
     void mouseReleaseEvent( QMouseEvent *event ) override;

diff --git a/src/gui/layout/qgslayoutviewtool.cpp b/src/gui/layout/qgslayoutviewtool.cpp
@@ -22,7 +22,10 @@ QgsLayoutViewTool::QgsLayoutViewTool( QgsLayoutView *view, const QString &name )
   , mView( view )
   , mToolName( name )
 {
-
+  connect( mView, &QgsLayoutView::willBeDeleted, this, [ = ]
+  {
+    mView = nullptr;
+  } );
 }
 
 bool QgsLayoutViewTool::isClickAndDrag( QPoint startViewPoint, QPoint endViewPoint ) const

diff --git a/src/gui/layout/qgslayoutviewtool.h b/src/gui/layout/qgslayoutviewtool.h
@@ -215,7 +215,7 @@ class GUI_EXPORT QgsLayoutViewTool : public QObject
   private:
 
     //! Pointer to layout view.
-    QPointer< QgsLayoutView > mView;
+    QgsLayoutView *mView = nullptr;
 
     QgsLayoutViewTool::Flags mFlags = nullptr;