Resolves: tdf#97331 use VclPtr instead of pointers to avoid crash

(cherry picked from commit 5d29ed1801a07d4649e095c25935b50f5ad32eb4)
(cherry picked from commit 53e693ccfb19aa653ab2b5762c10ae87c9320954)

Change-Id: Ia653a67046cb2cfb7c96367a7483ddc0cb29819e
Reviewed-on: https://gerrit.libreoffice.org/21810
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/vcl/source/window/winproc.cxx b/vcl/source/window/winproc.cxx
index 304753a02285..e708e18e82c2 100644
--- a/vcl/source/window/winproc.cxx
+++ b/vcl/source/window/winproc.cxx
@@ -1354,7 +1354,7 @@ static bool ImplCallWheelCommand( vcl::Window* pWindow, const Point& rPos,
 
 static bool acceptableWheelScrollTarget(const vcl::Window *pMouseWindow)
 {
-    return (pMouseWindow && pMouseWindow->IsInputEnabled() && !pMouseWindow->IsInModalMode());
+    return (pMouseWindow && !pMouseWindow->isDisposed() && pMouseWindow->IsInputEnabled() && !pMouseWindow->IsInModalMode());
 }
 
 //If the last event at the same absolute screen position was handled by a
@@ -1520,26 +1520,26 @@ public:
 bool HandleWheelEvent::HandleEvent(const SalWheelMouseEvent& rEvt)
 {
     static SalWheelMouseEvent aPreviousEvent;
-    static vcl::Window *pPreviousWindow;
+    static VclPtr<vcl::Window> xPreviousWindow;
 
     if (!Setup())
         return false;
 
-    vcl::Window *pMouseWindow = FindTarget();
+    VclPtr<vcl::Window> xMouseWindow = FindTarget();
 
     // avoid the problem that scrolling via wheel to this point brings a widget
     // under the mouse that also accepts wheel commands, so stick with the old
     // widget if the time gap is very small
-    if (shouldReusePreviousMouseWindow(aPreviousEvent, rEvt) && acceptableWheelScrollTarget(pPreviousWindow))
+    if (shouldReusePreviousMouseWindow(aPreviousEvent, rEvt) && acceptableWheelScrollTarget(xPreviousWindow))
     {
-        pMouseWindow = pPreviousWindow;
+        xMouseWindow = xPreviousWindow.get();
     }
 
     aPreviousEvent = rEvt;
 
-    pPreviousWindow = Dispatch(pMouseWindow);
+    xPreviousWindow = Dispatch(xMouseWindow);
 
-    return pPreviousWindow != NULL;
+    return xPreviousWindow;
 }
 
 class HandleGestureEvent : public HandleGestureEventBase