css: Add debug output for the css rules tree

When matching a widget against the set of rules we currently iterate
over *all* rules in the theme, trying to match them until we fullfill
our needs. This takes a pretty long time since themes have a lot of rules.

This is the first step towards making this faster. Every time the
ruleset changes we pre-calculate a decision tree where the nodes are either
list of rules to match against, or checks, such that if the check fails
we can ignore a whole subset of the tree.

The tree is built up in two levels, first we check if certain states must
be set, ignoring whole branches if not. Then in the level below we look
for css classes which are used by many rules.

At the leaf nodes we store references to the full list rulesets. These are
stored as array offset, which are sorted in index order, which means css prio
order, as the rulesets are sorted by that.

With this in place we can quickly prune large parts of the tree and then
merge the non-pruned result into a much smaller list of rules that we
need to do full checking on.

gtk/gtkcssprovider.c

@@ -994,6 +994,37 @@ struct GtkCssRuleset
   guint owns_widget_style : 1;
 };
 
+enum RulesetsTreeType {
+  RULESETS_TREE_TYPE_STATE,
+  RULESETS_TREE_TYPE_CLASS,
+  RULESETS_TREE_TYPE_RULES
+};
+
+typedef struct _GtkCssRulesetList GtkCssRulesetList;
+typedef struct _GtkCssRulesetsTree GtkCssRulesetsTree;
+
+struct _GtkCssRulesetList {
+  guint *rules;
+  guint num_rules;
+};
+
+struct _GtkCssRulesetsTree
+{
+  enum RulesetsTreeType type;
+  union {
+    GtkCssRulesetList rules;
+    struct {
+      GtkCssRulesetsTree *matched;
+      GtkStateFlags state;
+    } state;
+    struct {
+      GtkCssRulesetsTree *matched;
+      GQuark class;
+    } class;
+  } u;
+  GtkCssRulesetsTree *next;
+};
+
 struct _GtkCssScanner
 {
   GtkCssProvider *provider;
@@ -1011,6 +1042,8 @@ struct _GtkCssProviderPrivate
   GHashTable *keyframes;
 
   GArray *rulesets;
+  guint *rulesets_refs;
+  GtkCssRulesetsTree *rulesets_tree;
   GResource *resource;
 };
 
@@ -1027,6 +1060,7 @@ static void gtk_css_provider_finalize (GObject *object);
 static void gtk_css_style_provider_iface_init (GtkStyleProviderIface *iface);
 static void gtk_css_style_provider_private_iface_init (GtkStyleProviderPrivateInterface *iface);
 static void widget_property_value_list_free (WidgetPropertyValue *head);
+static void gtk_css_rulesets_tree_free (GtkCssRulesetsTree *tree);
 
 static gboolean
 gtk_css_provider_load_internal (GtkCssProvider *css_provider,
@@ -1561,6 +1595,117 @@ gtk_css_style_provider_get_keyframes (GtkStyleProviderPrivate *provider,
   return g_hash_table_lookup (css_provider->priv->keyframes, name);
 }
 
+static void
+collect_possible_rules (GPtrArray *rules_lists,
+			GtkCssRulesetsTree *tree,
+			const GtkCssMatcher *matcher)
+{
+  if (tree == NULL)
+    return;
+
+  switch (tree->type)
+    {
+    case RULESETS_TREE_TYPE_RULES:
+      g_ptr_array_add (rules_lists, &tree->u.rules);
+      break;
+    case RULESETS_TREE_TYPE_STATE:
+      if ((_gtk_css_matcher_get_state (matcher) & tree->u.state.state) == tree->u.state.state)
+	collect_possible_rules (rules_lists,
+				tree->u.state.matched,
+				matcher);
+      break;
+    case RULESETS_TREE_TYPE_CLASS:
+      if (_gtk_css_matcher_has_class (matcher, tree->u.class.class))
+	collect_possible_rules (rules_lists,
+				tree->u.class.matched,
+				matcher);
+      break;
+    }
+
+  collect_possible_rules (rules_lists,
+			  tree->next,
+			  matcher);
+}
+
+/* Merged two pre-sorted arrays of uints, assumes enough space in destination to fit a_len + b_len */
+static void
+merge_uints (guint *dest, const guint *a, int a_len, const guint* b, int b_len)
+{
+  const guint *a_end = a + a_len;
+  const guint *b_end = b + b_len;
+
+  while (a != a_end ||
+	 b != b_end)
+    {
+      if (a == a_end)
+	{
+	  memcpy (dest, b, sizeof (guint) * (b_end - b));
+	  break;
+	}
+      else if (b == b_end)
+	{
+	  memcpy (dest, a, sizeof (guint) * (a_end - a));
+	  break;
+	}
+      else if (*a <= *b)
+	*dest++ = *a++;
+      else
+	*dest++ = *b++;
+    }
+}
+
+static guint *
+find_possible_rules (GtkCssRulesetsTree *tree,
+		     const GtkCssMatcher *matcher,
+		     guint *num_refs_out)
+{
+  GPtrArray *rules_lists;
+  gint i;
+  guint *merged, *tmp_refs, *swap_ptr;
+  guint merged_size;
+  guint num_refs;
+
+  /* Collect all possible rules from the tree */
+  rules_lists = g_ptr_array_new ();
+  collect_possible_rules (rules_lists, tree, matcher);
+
+  /* Merge the separate sorted lists into one list */
+  num_refs = 0;
+  for (i = 0; i  < rules_lists->len; i++)
+    {
+      GtkCssRulesetList *list = (GtkCssRulesetList *)rules_lists->pdata[i];
+      num_refs += list->num_rules;
+    }
+
+  merged = g_new (guint, num_refs);
+  merged_size = 0;
+  tmp_refs = g_new (guint, num_refs);
+
+  /* Merge the already sorted refs list */
+  for (i = 0; i  < rules_lists->len; i++)
+    {
+      GtkCssRulesetList *list = (GtkCssRulesetList *)rules_lists->pdata[i];
+
+      if (i == 0)
+	memcpy (merged, list->rules, sizeof (*list->rules) * list->num_rules);
+      else
+	{
+	  merge_uints (tmp_refs, merged, merged_size, list->rules, list->num_rules);
+	  swap_ptr = merged;
+	  merged = tmp_refs;
+	  tmp_refs = swap_ptr;
+	}
+
+      merged_size += list->num_rules;
+    }
+
+  g_free (tmp_refs);
+  g_ptr_array_free (rules_lists, TRUE);
+
+  *num_refs_out = num_refs;
+  return merged;
+}
+
 static void
 gtk_css_style_provider_lookup (GtkStyleProviderPrivate *provider,
                                const GtkCssMatcher     *matcher,
@@ -1570,6 +1715,9 @@ gtk_css_style_provider_lookup (GtkStyleProviderPrivate *provider,
   GtkCssProviderPrivate *priv;
   GtkCssRuleset *ruleset;
   guint j;
+  gint i;
+  guint *refs;
+  guint num_refs;
 
   css_provider = GTK_CSS_PROVIDER (provider);
   priv = css_provider->priv;
@@ -1577,10 +1725,14 @@ gtk_css_style_provider_lookup (GtkStyleProviderPrivate *provider,
   if (priv->rulesets->len == 0)
     return;
 
-  for (ruleset = &g_array_index (priv->rulesets, GtkCssRuleset, priv->rulesets->len - 1);
+  refs = find_possible_rules (priv->rulesets_tree, matcher, &num_refs);
-       ruleset >= &g_array_index (priv->rulesets, GtkCssRuleset, 0);
+  if (num_refs == 0)
-       ruleset--)
+    return;
+
+  for (i = num_refs - 1; i >= 0; i--)
     {
+      ruleset = &g_array_index (priv->rulesets, GtkCssRuleset, refs[i]);
+
       if (ruleset->styles == NULL)
         continue;
 
@@ -1608,6 +1760,8 @@ gtk_css_style_provider_lookup (GtkStyleProviderPrivate *provider,
       if (_gtk_bitmask_is_empty (_gtk_css_lookup_get_missing (lookup)))
         break;
     }
+
+  g_free (refs);
 }
 
 static GtkCssChange
@@ -1618,15 +1772,21 @@ gtk_css_style_provider_get_change (GtkStyleProviderPrivate *provider,
   GtkCssProviderPrivate *priv;
   GtkCssChange change = 0;
   int i;
+  guint *refs;
+  guint num_refs;
 
   css_provider = GTK_CSS_PROVIDER (provider);
   priv = css_provider->priv;
 
-  for (i = priv->rulesets->len - 1; i >= 0; i--)
+  refs = find_possible_rules (priv->rulesets_tree, matcher, &num_refs);
+  if (num_refs == 0)
+    return change;
+
+  for (i = num_refs - 1; i >= 0; i--)
     {
       GtkCssRuleset *ruleset;
 
-      ruleset = &g_array_index (priv->rulesets, GtkCssRuleset, i);
+      ruleset = &g_array_index (priv->rulesets, GtkCssRuleset, refs[i]);
 
       if (ruleset->styles == NULL)
         continue;
@@ -1637,6 +1797,8 @@ gtk_css_style_provider_get_change (GtkStyleProviderPrivate *provider,
       change |= gtk_css_ruleset_get_change (ruleset);
     }
 
+  g_free (refs);
+
   return change;
 }
 
@@ -1663,6 +1825,8 @@ gtk_css_provider_finalize (GObject *object)
     gtk_css_ruleset_clear (&g_array_index (priv->rulesets, GtkCssRuleset, i));
 
   g_array_free (priv->rulesets, TRUE);
+  g_free (priv->rulesets_refs);
+  gtk_css_rulesets_tree_free (priv->rulesets_tree);
 
   g_hash_table_destroy (priv->symbolic_colors);
   g_hash_table_destroy (priv->keyframes);
@@ -1797,6 +1961,11 @@ gtk_css_provider_reset (GtkCssProvider *css_provider)
   g_hash_table_remove_all (priv->symbolic_colors);
   g_hash_table_remove_all (priv->keyframes);
 
+  g_free (priv->rulesets_refs);
+  priv->rulesets_refs = NULL;
+  gtk_css_rulesets_tree_free (priv->rulesets_tree);
+  priv->rulesets_tree = NULL;
+
   for (i = 0; i < priv->rulesets->len; i++)
     gtk_css_ruleset_clear (&g_array_index (priv->rulesets, GtkCssRuleset, i));
   g_array_set_size (priv->rulesets, 0);
@@ -2430,12 +2599,274 @@ gtk_css_provider_compare_rule (gconstpointer a_,
   return 0;
 }
 
+static void
+gtk_css_rulesets_tree_free (GtkCssRulesetsTree *tree)
+{
+  if (tree == NULL)
+    return;
+
+  switch (tree->type)
+    {
+    case RULESETS_TREE_TYPE_RULES:
+      break;
+    case RULESETS_TREE_TYPE_STATE:
+      gtk_css_rulesets_tree_free (tree->u.state.matched);
+      break;
+    case RULESETS_TREE_TYPE_CLASS:
+      gtk_css_rulesets_tree_free (tree->u.class.matched);
+      break;
+    }
+
+  gtk_css_rulesets_tree_free (tree->next);
+}
+
+static gint
+compare_refs_by_val (gconstpointer  pa,
+		     gconstpointer  pb,
+		     gpointer       user_data)
+{
+  guint a = *(guint *)pa;
+  guint b = *(guint *)pb;
+
+  return a - b;
+}
+
+static GtkCssRulesetsTree *
+subdivide_by_none (GtkCssProviderPrivate *priv, guint *refs, guint start, guint end)
+{
+  GtkCssRulesetsTree *tree;
+
+  tree = g_new0 (GtkCssRulesetsTree, 1);
+  tree->type = RULESETS_TREE_TYPE_RULES;
+  tree->u.rules.rules = refs + start;
+  tree->u.rules.num_rules = end - start;
+  tree->next = NULL;
+
+  /* Sort by rule index (i.e. css prio order) */
+  g_qsort_with_data (tree->u.rules.rules,
+		     tree->u.rules.num_rules,
+		     sizeof (guint),
+		     compare_refs_by_val,
+		     NULL);
+
+  return tree;
+}
+
+typedef struct {
+  GQuark class;
+  guint count;
+} GtkCssPseudoClassCount;
+
+static gint
+compare_class_count (gconstpointer  pa,
+		     gconstpointer  pb,
+		     gpointer       user_data)
+{
+  GtkCssPseudoClassCount *a = (GtkCssPseudoClassCount *)pa;
+  GtkCssPseudoClassCount *b = (GtkCssPseudoClassCount *)pb;
+
+  return b->count - a->count;
+}
+
+static GtkCssRulesetsTree *
+subdivide_by_class (GtkCssProviderPrivate *priv, guint *refs, guint start, guint end)
+{
+  GHashTable *count_ht;
+  GHashTableIter iter;
+  guint i, j, n_classes;
+  gpointer key, value;
+  GtkCssPseudoClassCount *class_count;
+  GtkCssRulesetsTree *tree;
+  GtkCssRulesetsTree *trees = NULL;
+
+  count_ht = g_hash_table_new (g_direct_hash, g_direct_equal);
+
+  for (i = start; i < end; i++)
+    {
+      GtkCssSelector *selector = g_array_index (priv->rulesets, GtkCssRuleset, refs[i]).selector;
+      GQuark *classes = _gtk_css_selector_get_primary_classes (selector);
+
+      for (j = 0; classes[j] != 0; j++)
+	{
+	  guint count = GPOINTER_TO_INT (g_hash_table_lookup (count_ht, GUINT_TO_POINTER (classes[j])));
+	  g_hash_table_replace (count_ht, GUINT_TO_POINTER (classes[j]), GUINT_TO_POINTER (count + 1));
+	}
+      g_free (classes);
+    }
+
+  n_classes = 0;
+  class_count = g_new (GtkCssPseudoClassCount, g_hash_table_size (count_ht));
+
+  g_hash_table_iter_init (&iter, count_ht);
+  while (g_hash_table_iter_next (&iter, &key, &value))
+    {
+      guint count = GPOINTER_TO_UINT (value);
+      /* Random cuttoff point here. Obviously if any given class has only one item
+	 with it, then adding a check doesn't help, and it uses memory. Where
+	 is the inflexion point? Lets make it 3... */
+      if (count >= 3)
+	{
+	  class_count[n_classes].class = GPOINTER_TO_UINT (key);
+	  class_count[n_classes].count = count;
+	  n_classes++;
+	}
+    }
+
+  g_hash_table_destroy (count_ht);
+
+  /* Sort largest class counts first */
+  g_qsort_with_data (class_count,
+		     n_classes,
+		     sizeof (*class_count),
+		     compare_class_count,
+		     NULL);
+
+  for (i = 0; i < n_classes; i++)
+    {
+      guint split = start;
+      for (j = start; j < end; j++)
+	{
+	  GtkCssSelector *selector = g_array_index (priv->rulesets, GtkCssRuleset, refs[j]).selector;
+
+	  if (_gtk_css_selector_has_primary_class (selector, class_count[i].class))
+	    {
+	      guint tmp = refs[split];
+	      refs[split] = refs[j];
+	      refs[j] = tmp;
+	      split++;
+	    }
+	}
+      /* Check size again sice nodes may have been used in other trees */
+      if (split - start > 3)
+	{
+	  tree = g_new (GtkCssRulesetsTree, 1);
+	  tree->type = RULESETS_TREE_TYPE_CLASS;
+	  tree->u.class.matched = subdivide_by_none (priv, refs, start, split);
+	  tree->u.class.class = class_count[i].class;
+
+	  tree->next = trees;
+	  trees = tree;
+	  start = split;
+	}
+    }
+
+  g_free (class_count);
+
+  if (start != end)
+    {
+      tree = subdivide_by_none (priv, refs, start, end);
+      tree->next = trees;
+      trees = tree;
+    }
+
+  return trees;
+}
+
+
+static GtkCssRulesetsTree *
+subdivide_by_state (GtkCssProviderPrivate *priv, guint *refs, guint start, guint end, guint state)
+{
+  GtkCssRulesetsTree *tree;
+  guint i;
+
+  if (end == start)
+    return NULL;
+
+  if (state == 0)
+    return subdivide_by_class (priv, refs, start, end);
+
+  // Find first non-set flag
+  for (i = start; i < end; i++)
+    {
+      GtkCssSelector *selector = g_array_index (priv->rulesets, GtkCssRuleset, refs[i]).selector;
+      if ((_gtk_css_selector_get_primary_state_flags (selector) & state) == 0)
+	break;
+    }
+
+  if (i == start || i == end) /* All or none set, no use subdividing by this */
+    return subdivide_by_state (priv, refs, start, end, state >> 1);
+
+  tree = g_new (GtkCssRulesetsTree, 1);
+  tree->type = RULESETS_TREE_TYPE_STATE;
+  tree->u.state.matched = subdivide_by_state (priv, refs, start, i, state >> 1);
+  tree->u.state.state = state;
+
+  tree->next = subdivide_by_state (priv, refs, i, end, state >> 1);
+
+  return tree;
+}
+
+static gint
+compare_refs_by_flags (gconstpointer  pa,
+		       gconstpointer  pb,
+		       gpointer       user_data)
+{
+  guint a = *(guint *)pa;
+  guint b = *(guint *)pb;
+  GArray *rulesets = user_data;
+  GtkCssSelector *selector_a, *selector_b;
+  guint32 flags_a, flags_b;
+
+  selector_a = g_array_index (rulesets, GtkCssRuleset, a).selector;
+  selector_b = g_array_index (rulesets, GtkCssRuleset, b).selector;
+
+  flags_a = _gtk_css_selector_get_primary_state_flags (selector_a);
+  flags_b = _gtk_css_selector_get_primary_state_flags (selector_b);
+
+  return flags_b - flags_a;
+}
+
+static void
+print_tree (GtkCssRulesetsTree *tree, int indent)
+{
+  if (tree == NULL)
+    return;
+
+  switch (tree->type)
+    {
+    case RULESETS_TREE_TYPE_RULES:
+      printf ("%*sCheck rules %p len %d\n", indent, "", tree->u.rules.rules, tree->u.rules.num_rules);
+      break;
+    case RULESETS_TREE_TYPE_STATE:
+      printf ("%*sMatch state 0x%x ->\n", indent, "", tree->u.state.state);
+      print_tree (tree->u.state.matched, indent + 4);
+      break;
+    case RULESETS_TREE_TYPE_CLASS:
+      printf ("%*sMatch class %s ->\n", indent, "", g_quark_to_string (tree->u.class.class));
+      print_tree (tree->u.class.matched, indent + 4);
+      break;
+    }
+
+  print_tree (tree->next, indent);
+}
+
 static void
 gtk_css_provider_postprocess (GtkCssProvider *css_provider)
 {
   GtkCssProviderPrivate *priv = css_provider->priv;
+  guint *refs, i;
 
   g_array_sort (priv->rulesets, gtk_css_provider_compare_rule);
+
+  refs = g_new (guint, priv->rulesets->len);
+  priv->rulesets_refs = refs;
+
+  for (i = 0; i < priv->rulesets->len; i++)
+    refs[i] = i;
+
+  /* Sort by flags, so that high bits set is sorted first at each level */
+  g_qsort_with_data (refs,
+		     priv->rulesets->len,
+		     sizeof (guint),
+		     compare_refs_by_flags,
+		     priv->rulesets);
+
+  priv->rulesets_tree = subdivide_by_state (priv, refs, 0, priv->rulesets->len, GTK_STATE_FLAG_BACKDROP);
+  if (g_getenv ("GTK_CSS_DEBUG_TREE"))
+    {
+      g_print ("Rulesets tree for proviced %p (%d rules)\n", css_provider, priv->rulesets->len);
+      print_tree (priv->rulesets_tree, 1);
+    }
 }
 
 static gboolean

gtk/gtkcssselector.c

@@ -38,6 +38,7 @@ struct _GtkCssSelectorClass {
   guint         increase_id_specificity :1;
   guint         increase_class_specificity :1;
   guint         increase_element_specificity :1;
+  guint         is_simple :1;
 };
 
 struct _GtkCssSelector
@@ -112,7 +113,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_DESCENDANT = {
   gtk_css_selector_descendant_print,
   gtk_css_selector_descendant_match,
   gtk_css_selector_descendant_get_change,
-  FALSE, FALSE, FALSE
+  FALSE, FALSE, FALSE, FALSE
 };
 
 /* CHILD */
@@ -147,7 +148,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_CHILD = {
   gtk_css_selector_child_print,
   gtk_css_selector_child_match,
   gtk_css_selector_child_get_change,
-  FALSE, FALSE, FALSE
+  FALSE, FALSE, FALSE, FALSE
 };
 
 /* SIBLING */
@@ -187,7 +188,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_SIBLING = {
   gtk_css_selector_sibling_print,
   gtk_css_selector_sibling_match,
   gtk_css_selector_sibling_get_change,
-  FALSE, FALSE, FALSE
+  FALSE, FALSE, FALSE, FALSE
 };
 
 /* ADJACENT */
@@ -222,7 +223,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_ADJACENT = {
   gtk_css_selector_adjacent_print,
   gtk_css_selector_adjacent_match,
   gtk_css_selector_adjacent_get_change,
-  FALSE, FALSE, FALSE
+  FALSE, FALSE, FALSE, FALSE
 };
 
 /* ANY */
@@ -262,7 +263,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_ANY = {
   gtk_css_selector_any_print,
   gtk_css_selector_any_match,
   gtk_css_selector_any_get_change,
-  FALSE, FALSE, FALSE
+  FALSE, FALSE, FALSE, TRUE
 };
 
 /* NAME */
@@ -295,7 +296,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_NAME = {
   gtk_css_selector_name_print,
   gtk_css_selector_name_match,
   gtk_css_selector_name_get_change,
-  FALSE, FALSE, TRUE
+  FALSE, FALSE, TRUE, TRUE
 };
 
 /* REGION */
@@ -341,7 +342,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_REGION = {
   gtk_css_selector_region_print,
   gtk_css_selector_region_match,
   gtk_css_selector_region_get_change,
-  FALSE, FALSE, TRUE
+  FALSE, FALSE, TRUE, TRUE
 };
 
 /* CLASS */
@@ -375,7 +376,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_CLASS = {
   gtk_css_selector_class_print,
   gtk_css_selector_class_match,
   gtk_css_selector_class_get_change,
-  FALSE, TRUE, FALSE
+  FALSE, TRUE, FALSE, TRUE
 };
 
 /* ID */
@@ -409,7 +410,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_ID = {
   gtk_css_selector_id_print,
   gtk_css_selector_id_match,
   gtk_css_selector_id_get_change,
-  TRUE, FALSE, FALSE
+  TRUE, FALSE, FALSE, TRUE
 };
 
 /* PSEUDOCLASS FOR STATE */
@@ -430,18 +431,15 @@ gtk_css_selector_pseudoclass_state_print (const GtkCssSelector *selector,
   guint i, state;
 
   state = GPOINTER_TO_UINT (selector->data);
-  g_string_append_c (string, ':');
 
   for (i = 0; i < G_N_ELEMENTS (state_names); i++)
     {
       if (state == (1 << i))
         {
+	  g_string_append_c (string, ':');
           g_string_append (string, state_names[i]);
-          return;
         }
     }
-
-  g_assert_not_reached ();
 }
 
 static gboolean
@@ -467,7 +465,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_PSEUDOCLASS_STATE = {
   gtk_css_selector_pseudoclass_state_print,
   gtk_css_selector_pseudoclass_state_match,
   gtk_css_selector_pseudoclass_state_get_change,
-  FALSE, TRUE, FALSE
+  FALSE, TRUE, FALSE, TRUE
 };
 
 /* PSEUDOCLASS FOR POSITION */
@@ -708,7 +706,7 @@ static const GtkCssSelectorClass GTK_CSS_SELECTOR_PSEUDOCLASS_POSITION = {
   gtk_css_selector_pseudoclass_position_print,
   gtk_css_selector_pseudoclass_position_match,
   gtk_css_selector_pseudoclass_position_get_change,
-  FALSE, TRUE, FALSE
+  FALSE, TRUE, FALSE, TRUE
 };
 
 /* API */
@@ -950,9 +948,16 @@ parse_selector_pseudo_class (GtkCssParser   *parser,
       if (_gtk_css_parser_try (parser, pseudo_classes[i].name, FALSE))
         {
           if (pseudo_classes[i].state_flag)
-            selector = gtk_css_selector_new (&GTK_CSS_SELECTOR_PSEUDOCLASS_STATE,
+	    {
-                                             selector,
+	      /* Piggy back on previous pseudoclass if any */
-                                             GUINT_TO_POINTER (pseudo_classes[i].state_flag));
+	      if (selector && selector->class == &GTK_CSS_SELECTOR_PSEUDOCLASS_STATE)
+		selector->data = GUINT_TO_POINTER (GPOINTER_TO_UINT (selector->data) |
+						   pseudo_classes[i].state_flag);
+	      else
+		selector = gtk_css_selector_new (&GTK_CSS_SELECTOR_PSEUDOCLASS_STATE,
+						 selector,
+						 GUINT_TO_POINTER (pseudo_classes[i].state_flag));
+	    }
           else
             selector = gtk_css_selector_new (&GTK_CSS_SELECTOR_PSEUDOCLASS_POSITION,
                                              selector,
@@ -1172,3 +1177,49 @@ _gtk_css_selector_get_state_flags (const GtkCssSelector *selector)
   return state;
 }
 
+GtkStateFlags
+_gtk_css_selector_get_primary_state_flags (const GtkCssSelector *selector)
+{
+  GtkStateFlags state = 0;
+
+  g_return_val_if_fail (selector != NULL, 0);
+
+  for (; selector && selector->class->is_simple; selector = gtk_css_selector_previous (selector))
+    {
+      if (selector->class == &GTK_CSS_SELECTOR_PSEUDOCLASS_STATE)
+	state |= GPOINTER_TO_UINT (selector->data);
+    }
+
+  return state;
+}
+
+GQuark *
+_gtk_css_selector_get_primary_classes (const GtkCssSelector *selector)
+{
+  GArray *array = g_array_new (TRUE, FALSE, sizeof (GQuark));
+
+  g_return_val_if_fail (selector != NULL, 0);
+
+  for (; selector && selector->class->is_simple; selector = gtk_css_selector_previous (selector))
+    {
+      if (selector->class == &GTK_CSS_SELECTOR_CLASS)
+	g_array_append_val (array, selector->data);
+    }
+
+  return (GQuark *)g_array_free (array, FALSE);
+}
+
+gboolean
+_gtk_css_selector_has_primary_class (const GtkCssSelector *selector, GQuark class)
+{
+  g_return_val_if_fail (selector != NULL, 0);
+
+  for (; selector && selector->class->is_simple; selector = gtk_css_selector_previous (selector))
+    {
+      if (selector->class == &GTK_CSS_SELECTOR_CLASS)
+	if (GPOINTER_TO_UINT (selector->data) == class)
+	  return TRUE;
+    }
+
+  return FALSE;
+}

gtk/gtkcssselectorprivate.h

@@ -40,6 +40,11 @@ gboolean          _gtk_css_selector_matches         (const GtkCssSelector   *sel
 int               _gtk_css_selector_compare         (const GtkCssSelector   *a,
                                                      const GtkCssSelector   *b);
 
+GtkStateFlags     _gtk_css_selector_get_primary_state_flags (const GtkCssSelector *selector);
+GQuark *          _gtk_css_selector_get_primary_classes     (const GtkCssSelector *selector);
+gboolean          _gtk_css_selector_has_primary_class       (const GtkCssSelector *selector,
+							     GQuark                class);
+
 G_END_DECLS
 
 #endif /* __GTK_CSS_SELECTOR_PRIVATE_H__ */