[gtk/matthiasc/css-change-tracking-4: 15/20] Revert "Remove no longer used code"

[Matthias Clasen <matthiasc src gnome org>]

commit 7d72703d54d2676e1d4eec4b9a5d246f7499395d
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jan 17 10:54:37 2020 -0500

    Revert "Remove no longer used code"
    
    This reverts commit 105acfe90866543904467b13fecdbed108cf43b2.

 gtk/gtkcssselector.c        | 68 +++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkcssselectorprivate.h |  2 ++
 2 files changed, 70 insertions(+)
---
diff --git a/gtk/gtkcssselector.c b/gtk/gtkcssselector.c
index 8957e49413..9844e2ea65 100644
--- a/gtk/gtkcssselector.c
+++ b/gtk/gtkcssselector.c
@@ -1877,12 +1877,80 @@ _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 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)
+{
+  GtkCssChange change = 0;
+  const GtkCssSelectorTree *prev;
+
+  for (prev = gtk_css_selector_tree_get_previous (tree);
+       prev != NULL;
+       prev = gtk_css_selector_tree_get_sibling (prev))
+    change |= gtk_css_selector_tree_collect_change (prev);
+
+  change = tree->selector.class->get_change (&tree->selector, change);
+
+  return change;
+}
+
+static GtkCssChange
+gtk_css_selector_tree_get_change (const GtkCssSelectorTree *tree,
+                                 const GtkCssMatcher      *matcher)
+{
+  GtkCssChange change = 0;
+  const GtkCssSelectorTree *prev;
+
+  if (!gtk_css_selector_match (&tree->selector, matcher))
+    return 0;
+
+  if (!tree->selector.class->is_simple)
+    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);
+
+  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;
+}
+
 gboolean
 _gtk_css_selector_tree_is_empty (const GtkCssSelectorTree *tree)
 {
   return tree == NULL;
 }
 
+GtkCssChange
+_gtk_css_selector_tree_get_change_all (const GtkCssSelectorTree *tree,
+                                      const GtkCssMatcher *matcher)
+{
+  GtkCssChange change;
+
+  change = 0;
+
+  /* no need to foreach here because we abort for non-simple selectors */
+  for (; tree != NULL;
+       tree = gtk_css_selector_tree_get_sibling (tree))
+    change |= gtk_css_selector_tree_get_change (tree, matcher);
+
+  /* Never return reserved bit set */
+  return change & ~GTK_CSS_CHANGE_RESERVED_BIT;
+}
+
 #ifdef PRINT_TREE
 static void
 _gtk_css_selector_tree_print (const GtkCssSelectorTree *tree, GString *str, char *prefix)
diff --git a/gtk/gtkcssselectorprivate.h b/gtk/gtkcssselectorprivate.h
index 7b7ba1073c..6f35917c6e 100644
--- a/gtk/gtkcssselectorprivate.h
+++ b/gtk/gtkcssselectorprivate.h
@@ -43,6 +43,8 @@ int               _gtk_css_selector_compare         (const GtkCssSelector   *a,
 void         _gtk_css_selector_tree_free             (GtkCssSelectorTree       *tree);
 GPtrArray *  _gtk_css_selector_tree_match_all        (const GtkCssSelectorTree *tree,
                                                      const GtkCssMatcher      *matcher);
+GtkCssChange _gtk_css_selector_tree_get_change_all   (const GtkCssSelectorTree *tree,
+                                                     const GtkCssMatcher *matcher);
 void         _gtk_css_selector_tree_match_print      (const GtkCssSelectorTree *tree,
                                                      GString                  *str);
 gboolean     _gtk_css_selector_tree_is_empty         (const GtkCssSelectorTree *tree) G_GNUC_CONST;