Bug #781893 (Crash after moving a Bezier node after Knot path effect)

Although issue not solved, prevent Inkscape from crashing. Add some code to make code more robust.

(bzr r11547)

1 files changed, 47 insertions, 17 deletions

diff --git a/src/ui/tool/control-point.cpp b/src/ui/tool/control-point.cpp
index fbc9858cc..8c4924f26 100644
--- a/src/ui/tool/control-point.cpp
+++ b/src/ui/tool/control-point.cpp
@@ -211,6 +211,9 @@ void ControlPoint::_setPixbuf(Glib::RefPtr<Gdk::Pixbuf> p)
 // re-routes events into the virtual function
 int ControlPoint::_event_handler(SPCanvasItem */*item*/, GdkEvent *event, ControlPoint *point)
 {
+    if ((point == NULL) || (point->_desktop == NULL)) {
+        return FALSE;
+    }
     return point->_eventHandler(point->_desktop->event_context, event) ? TRUE : FALSE;
 }
 
@@ -220,6 +223,24 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
     // NOTE the static variables below are shared for all points!
     // TODO handle clicks and drags from other buttons too
 
+    if (event == NULL)
+    {
+        return false;
+    }
+    
+    if (event_context == NULL)
+    {
+        return false;
+    }
+    if (_desktop == NULL)
+    {
+        return false;
+    }
+    if(event_context->desktop !=_desktop)
+    {
+        g_warning ("ControlPoint: desktop pointers not equal!");
+        //return false;
+    }
     // offset from the pointer hotspot to the center of the grabbed knot in desktop coords
     static Geom::Point pointer_offset;
     // number of last doubleclicked button
@@ -227,7 +248,8 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
     
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     int drag_tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
-    
+    GdkEventMotion em;
+    SPCanvas* Ca;
     switch(event->type)
     {   
     case GDK_BUTTON_PRESS:
@@ -253,18 +275,22 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
         return true;
         
     case GDK_MOTION_NOTIFY:
-        combine_motion_events(_desktop->canvas, event->motion, 0);
-        if (_event_grab && !_desktop->event_context->space_panning) {
+        Ca = _desktop->canvas;
+        em = event->motion;
+        combine_motion_events(Ca, em, 0);
+        if (_event_grab && ! event_context->space_panning) {
             _desktop->snapindicator->remove_snaptarget(); 
             bool transferred = false;
             if (!_drag_initiated) {
-                bool t = fabs(event->motion.x - _drag_event_origin[Geom::X]) <= drag_tolerance &&
-                         fabs(event->motion.y - _drag_event_origin[Geom::Y]) <= drag_tolerance;
-                if (t) return true;
+                bool t = fabs(em.x - _drag_event_origin[Geom::X]) <= drag_tolerance &&
+                         fabs(em.y - _drag_event_origin[Geom::Y]) <= drag_tolerance;
+                if (t){
+                    return true;
+                }
 
                 // if we are here, it means the tolerance was just exceeded.
                 _drag_origin = _position;
-                transferred = grabbed(&event->motion);
+                transferred = grabbed(&em);
                 // _drag_initiated might change during the above virtual call
                 if (!_drag_initiated) {
                     // this guarantees smooth redraws while dragging
@@ -275,15 +301,14 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
             if (!transferred) {
                 // dragging in progress
                 Geom::Point new_pos = _desktop->w2d(event_point(event->motion)) + pointer_offset;
-                
                 // the new position is passed by reference and can be changed in the handlers.
-                dragged(new_pos, &event->motion);
+                dragged(new_pos, &em);
                 move(new_pos);
-                _updateDragTip(&event->motion); // update dragging tip after moving to new position
+                _updateDragTip(&em); // update dragging tip after moving to new position
                 
                 _desktop->scroll_to_point(new_pos);
                 _desktop->set_coordinate_status(_position);
-                sp_event_context_snap_delay_handler(_desktop->event_context, NULL,
+                sp_event_context_snap_delay_handler(event_context, NULL,
                     (gpointer) this, &event->motion,
                     DelayedSnapEvent::CONTROL_POINT_HANDLER);
             }
@@ -299,8 +324,9 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
             // We must snap at some point in time though, and this is our last chance)
             // PS: For other contexts this is handled already in sp_event_context_item_handler or
             // sp_event_context_root_handler
-            if (_desktop->event_context->_delayed_snap_event) {
-                sp_event_context_snap_watchdog_callback(_desktop->event_context->_delayed_snap_event);
+            //if (_desktop && _desktop->event_context && _desktop->event_context->_delayed_snap_event) {
+            if (event_context->_delayed_snap_event) {
+                sp_event_context_snap_watchdog_callback(event_context->_delayed_snap_event);
             }
 
             sp_canvas_item_ungrab(_canvas_item, event->button.time);
@@ -335,8 +361,9 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
         if (_event_grab && !event->grab_broken.keyboard) {
             {
                 ungrabbed(NULL);
-                if (_drag_initiated)
+                if (_drag_initiated) {
                     _desktop->canvas->endForcedFullRedraws();
+                }
             }
             _setState(STATE_NORMAL);
             _event_grab = false;
@@ -355,7 +382,7 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
             if (!_drag_initiated) break;
 
             // temporarily disable snapping - we might snap to a different place than we were initially
-            sp_event_context_discard_delayed_snap_event(_desktop->event_context);
+            sp_event_context_discard_delayed_snap_event(event_context);
             SnapPreferences &snapprefs = _desktop->namedview->snap_manager.snapprefs;
             bool snap_save = snapprefs.getSnapEnabledGlobally();
             snapprefs.setSnapEnabledGlobally(false);
@@ -389,7 +416,8 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
 
             ungrabbed(NULL); // ungrabbed handlers can handle a NULL event
             snapprefs.setSnapEnabledGlobally(snap_save);
-            } return true;
+            }
+            return true;
         case GDK_KEY_Tab:
             {// Downcast from ControlPoint to TransformHandle, if possible
              // This is an ugly hack; we should have the transform handle intercept the keystrokes itself
@@ -415,7 +443,9 @@ bool ControlPoint::_eventHandler(SPEventContext *event_context, GdkEvent *event)
         }
         // Do not break here, to allow for updating tooltips and such
     case GDK_KEY_RELEASE: 
-        if (mouseovered_point != this) return false;
+        if (mouseovered_point != this){
+            return false;
+        }
         if (_drag_initiated) {
             return true; // this prevents the tool from overwriting the drag tip
         } else {