[gtk] Stop walking parent surfaces for crossing event generation

[Matthias Clasen <matthiasc src gnome org>]

commit 81658105f7d675ee76dd7df7f79448aee5f47197
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Mar 22 15:20:06 2019 -0400

    Stop walking parent surfaces for crossing event generation
    
    We basically don't have child surfaces anymore (the last
    use in popovers is on the way out). This really needs
    to be done in terms of widgets, not surfaces. For now,
    just stop walking parent surfaces.

 gtk/gtkwidget.c | 140 ++------------------------------------------------------
 1 file changed, 4 insertions(+), 136 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 7b5e2ed1e5..46f8eb7f45 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -8608,29 +8608,6 @@ synth_crossing (GtkWidget       *widget,
  * @mode: the #GdkCrossingMode to place on the synthesized events.
  *
  * Generate crossing event(s) on widget state (sensitivity) or GTK+ grab change.
- *
- * The real pointer window is the window that most recently received an enter notify
- * event.  Windows that don’t select for crossing events can’t become the real
- * pointer window.  The real pointer widget that owns the real pointer window.  The
- * effective pointer window is the same as the real pointer window unless the real
- * pointer widget is either insensitive or there is a grab on a widget that is not
- * an ancestor of the real pointer widget (in which case the effective pointer
- * window should be the root window).
- *
- * When the effective pointer window is the same as the real pointer window, we
- * receive crossing events from the windowing system.  When the effective pointer
- * window changes to become different from the real pointer window we synthesize
- * crossing events, attempting to follow X protocol rules:
- *
- * When the root window becomes the effective pointer window:
- *   - leave notify on real pointer window, detail Ancestor
- *   - leave notify on all of its ancestors, detail Virtual
- *   - enter notify on root window, detail Inferior
- *
- * When the root window ceases to be the effective pointer window:
- *   - leave notify on root window, detail Inferior
- *   - enter notify on all ancestors of real pointer window, detail Virtual
- *   - enter notify on real pointer window, detail Ancestor
  */
 void
 _gtk_widget_synthesize_crossing (GtkWidget       *from,
@@ -8662,132 +8639,23 @@ _gtk_widget_synthesize_crossing (GtkWidget       *from,
     ;
   else if (from_surface != NULL && to_surface == NULL)
     {
-      GList *from_ancestors = NULL, *list;
-      GdkSurface *from_ancestor = from_surface;
-
-      while (from_ancestor != NULL)
-       {
-         from_ancestor = gdk_surface_get_parent (from_ancestor);
-          if (from_ancestor == NULL)
-            break;
-          from_ancestors = g_list_prepend (from_ancestors, from_ancestor);
-       }
-
       synth_crossing (from, GDK_LEAVE_NOTIFY, from_surface,
                      device, mode, GDK_NOTIFY_ANCESTOR);
-      for (list = g_list_last (from_ancestors); list; list = list->prev)
-       {
-         synth_crossing (NULL, GDK_LEAVE_NOTIFY, (GdkSurface *) list->data,
-                         device, mode, GDK_NOTIFY_VIRTUAL);
-       }
-
-      /* XXX: enter/inferior on root window? */
-
-      g_list_free (from_ancestors);
     }
   else if (from_surface == NULL && to_surface != NULL)
     {
-      GList *to_ancestors = NULL, *list;
-      GdkSurface *to_ancestor = to_surface;
-
-      while (to_ancestor != NULL)
-       {
-         to_ancestor = gdk_surface_get_parent (to_ancestor);
-         if (to_ancestor == NULL)
-            break;
-          to_ancestors = g_list_prepend (to_ancestors, to_ancestor);
-        }
-
-      /* XXX: leave/inferior on root window? */
-
-      for (list = to_ancestors; list; list = list->next)
-       {
-         synth_crossing (NULL, GDK_ENTER_NOTIFY, (GdkSurface *) list->data,
-                         device, mode, GDK_NOTIFY_VIRTUAL);
-       }
       synth_crossing (to, GDK_ENTER_NOTIFY, to_surface,
                      device, mode, GDK_NOTIFY_ANCESTOR);
-
-      g_list_free (to_ancestors);
     }
   else if (from_surface == to_surface)
     ;
   else
     {
-      GList *from_ancestors = NULL, *to_ancestors = NULL, *list;
-      GdkSurface *from_ancestor = from_surface, *to_ancestor = to_surface;
-
-      while (from_ancestor != NULL || to_ancestor != NULL)
-       {
-         if (from_ancestor != NULL)
-           {
-             from_ancestor = gdk_surface_get_parent (from_ancestor);
-             if (from_ancestor == to_surface)
-               break;
-              if (from_ancestor)
-               from_ancestors = g_list_prepend (from_ancestors, from_ancestor);
-           }
-         if (to_ancestor != NULL)
-           {
-             to_ancestor = gdk_surface_get_parent (to_ancestor);
-             if (to_ancestor == from_surface)
-               break;
-              if (to_ancestor)
-               to_ancestors = g_list_prepend (to_ancestors, to_ancestor);
-           }
-       }
-      if (to_ancestor == from_surface)
-       {
-         if (mode != GDK_CROSSING_GTK_UNGRAB)
-           synth_crossing (from, GDK_LEAVE_NOTIFY, from_surface,
-                           device, mode, GDK_NOTIFY_INFERIOR);
-         for (list = to_ancestors; list; list = list->next)
-           synth_crossing (NULL, GDK_ENTER_NOTIFY, (GdkSurface *) list->data,
-                           device, mode, GDK_NOTIFY_VIRTUAL);
-         synth_crossing (to, GDK_ENTER_NOTIFY, to_surface,
-                         device, mode, GDK_NOTIFY_ANCESTOR);
-       }
-      else if (from_ancestor == to_surface)
-       {
-         synth_crossing (from, GDK_LEAVE_NOTIFY, from_surface,
-                         device, mode, GDK_NOTIFY_ANCESTOR);
-         for (list = g_list_last (from_ancestors); list; list = list->prev)
-           {
-             synth_crossing (NULL, GDK_LEAVE_NOTIFY, (GdkSurface *) list->data,
-                             device, mode, GDK_NOTIFY_VIRTUAL);
-           }
-         if (mode != GDK_CROSSING_GTK_GRAB)
-           synth_crossing (to, GDK_ENTER_NOTIFY, to_surface,
-                           device, mode, GDK_NOTIFY_INFERIOR);
-       }
-      else
-       {
-         while (from_ancestors != NULL && to_ancestors != NULL
-                && from_ancestors->data == to_ancestors->data)
-           {
-             from_ancestors = g_list_delete_link (from_ancestors,
-                                                  from_ancestors);
-             to_ancestors = g_list_delete_link (to_ancestors, to_ancestors);
-           }
-
-         synth_crossing (from, GDK_LEAVE_NOTIFY, from_surface,
-                         device, mode, GDK_NOTIFY_NONLINEAR);
+      synth_crossing (from, GDK_LEAVE_NOTIFY, from_surface,
+                      device, mode, GDK_NOTIFY_NONLINEAR);
 
-         for (list = g_list_last (from_ancestors); list; list = list->prev)
-           {
-             synth_crossing (NULL, GDK_LEAVE_NOTIFY, (GdkSurface *) list->data,
-                             device, mode, GDK_NOTIFY_NONLINEAR_VIRTUAL);
-           }
-         for (list = to_ancestors; list; list = list->next)
-           {
-             synth_crossing (NULL, GDK_ENTER_NOTIFY, (GdkSurface *) list->data,
-                             device, mode, GDK_NOTIFY_NONLINEAR_VIRTUAL);
-           }
-         synth_crossing (to, GDK_ENTER_NOTIFY, to_surface,
-                         device, mode, GDK_NOTIFY_NONLINEAR);
-       }
-      g_list_free (from_ancestors);
-      g_list_free (to_ancestors);
+      synth_crossing (to, GDK_ENTER_NOTIFY, to_surface,
+                      device, mode, GDK_NOTIFY_NONLINEAR);
     }
 }