[gtk+] cssselector: Reintroduce GOT_MATCH

[Benjamin Otte <otte src gnome org>]

commit 78223932c572214f7a1a738c953299d864451724
Author: Benjamin Otte <otte redhat com>
Date:   Mon Jan 5 21:15:19 2015 +0100

    cssselector: Reintroduce GOT_MATCH
    
    I removed it in 14f5ce710856708dc80fcc98cb5eb2ba257f34ad because I
    thought it was unnecessary, but it wasn't. When we build a tree like
    this:
    
    .matches ─┬─ .doesntmatch
              └─ .alsodoesntmatch
    
    We would get the changes for the .matches part returned. This is however
    only right if that node of the tree contains results. If results only
    exist with the child nodes (all of which don't match), then this part
    should not match either.

 gtk/gtkcssselector.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkcssselector.c b/gtk/gtkcssselector.c
index 8c8010c..eae014e 100644
--- a/gtk/gtkcssselector.c
+++ b/gtk/gtkcssselector.c
@@ -1754,6 +1754,17 @@ _gtk_css_selector_tree_match_all (const GtkCssSelectorTree *tree,
   return array;
 }
 
+/* When checking for changes via the tree we need to know if a rule further
+   down the tree matched, because if so we need to add "our bit" to the
+   Change. For instance in a a match like *.class:active we'll
+   get a tree that first checks :active, if that matches we continue down
+   to the tree, and if we get a match we add CHANGE_CLASS. However, the
+   end of the tree where we have a match is an ANY which doesn't actually
+   modify the change, so we don't know if we have a match or not. We fix
+   this by setting GTK_CSS_CHANGE_GOT_MATCH which lets us guarantee
+   that change != 0 on any match. */
+#define GTK_CSS_CHANGE_GOT_MATCH GTK_CSS_CHANGE_RESERVED_BIT
+
 static GtkCssChange
 gtk_css_selector_tree_collect_change (const GtkCssSelectorTree *tree)
 {
@@ -1781,14 +1792,15 @@ gtk_css_selector_tree_get_change (const GtkCssSelectorTree *tree,
     return 0;
 
   if (!tree->selector.class->is_simple)
-    return gtk_css_selector_tree_collect_change (tree);
+    return gtk_css_selector_tree_collect_change (tree) | GTK_CSS_CHANGE_GOT_MATCH;
 
   for (prev = gtk_css_selector_tree_get_previous (tree);
        prev != NULL;
        prev = gtk_css_selector_tree_get_sibling (prev))
     change |= gtk_css_selector_tree_get_change (prev, matcher);
 
-  change = tree->selector.class->get_change (&tree->selector, change);
+  if (change || gtk_css_selector_tree_get_matches (tree))
+    change = tree->selector.class->get_change (&tree->selector, change & ~GTK_CSS_CHANGE_GOT_MATCH) | 
GTK_CSS_CHANGE_GOT_MATCH;
 
   return change;
 }
@@ -1807,7 +1819,7 @@ _gtk_css_selector_tree_get_change_all (const GtkCssSelectorTree *tree,
     change |= gtk_css_selector_tree_get_change (tree, matcher);
 
   /* Never return reserved bit set */
-  return change;
+  return change & ~GTK_CSS_CHANGE_RESERVED_BIT;
 }
 
 #ifdef PRINT_TREE