[gtk+] stylecontext: Compute correct changes

[Benjamin Otte <otte src gnome org>]

commit 8874a06ba0b213e87ac5b16f50cd822935e67ffd
Author: Benjamin Otte <otte redhat com>
Date:   Fri Aug 24 16:28:47 2012 +0200

    stylecontext: Compute correct changes
    
    ... in the case where no change of the DOM tree actually happened.
    
    We don't do anything yet with that information, this patch just
    correctly computes it.

 gtk/gtkstylecontext.c |   30 +++++++++++++++++++-----------
 1 files changed, 19 insertions(+), 11 deletions(-)
---
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 281be0f..a98f194 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -3071,6 +3071,8 @@ _gtk_style_context_validate (GtkStyleContext  *context,
                              const GtkBitmask *parent_changes)
 {
   GtkStyleContextPrivate *priv;
+  GtkStyleInfo *info;
+  StyleData *current;
   GtkBitmask *changes;
   GSList *list;
 
@@ -3095,23 +3097,22 @@ _gtk_style_context_validate (GtkStyleContext  *context,
   if (G_UNLIKELY (gtk_get_debug_flags () & GTK_DEBUG_NO_CSS_CACHE))
     change = GTK_CSS_CHANGE_ANY;
 
-  if (!priv->invalid && change == 0)
+  if (!priv->invalid && change == 0 && _gtk_bitmask_is_empty (parent_changes))
     return;
 
   priv->pending_changes = 0;
   gtk_style_context_set_invalid (context, FALSE);
 
+  info = priv->info;
+  if (info->data)
+    current = style_data_ref (info->data);
+  else
+    current = NULL;
+
   /* Try to avoid invalidating if we can */
-  if (gtk_style_context_needs_full_revalidate (context, change))
+  if (current == NULL ||
+      gtk_style_context_needs_full_revalidate (context, change))
     {
-      GtkStyleInfo *info = priv->info;
-      StyleData *current;
-
-      if (info->data)
-        current = style_data_ref (info->data);
-      else
-        current = NULL;
-
       if ((priv->relevant_changes & change) & ~GTK_STYLE_CONTEXT_CACHED_CHANGE)
         gtk_style_context_clear_cache (context);
       else
@@ -3137,7 +3138,14 @@ _gtk_style_context_validate (GtkStyleContext  *context,
         }
     }
   else
-    changes = _gtk_bitmask_new ();
+    {
+      changes = _gtk_bitmask_copy (parent_changes);
+      changes = _gtk_bitmask_intersect (changes, current->store->depends_on_parent);
+      if (_gtk_bitmask_get (changes, GTK_CSS_PROPERTY_COLOR))
+        changes = _gtk_bitmask_union (changes, current->store->depends_on_color);
+      if (_gtk_bitmask_get (changes, GTK_CSS_PROPERTY_FONT_SIZE))
+        changes = _gtk_bitmask_union (changes, current->store->depends_on_font_size);
+    }
 
   if (change & GTK_CSS_CHANGE_ANIMATE &&
       gtk_style_context_is_animating (context))