match_all: Only allocate an array when needed

My statistics show that more than half of all calls end up
with 0 matches, so we can avoid some overhead by not allocating
an array at all in this case.

gtk/gtkcssprovider.c

@@ -1638,6 +1638,8 @@ verify_tree_get_change_results (GtkCssProvider *provider,
     int i;
 
     tree_rules = _gtk_css_selector_tree_match_all (provider->priv->tree, matcher);
+    if (tree_rules)
+      {
         verify_tree_match_results (provider, matcher, tree_rules);
 
         for (i = tree_rules->len - 1; i >= 0; i--)
@@ -1649,6 +1651,9 @@ verify_tree_get_change_results (GtkCssProvider *provider,
             verify_change |= _gtk_css_selector_get_change (ruleset->selector);
           }
 
+        g_ptr_array_free (tree_rules, TRUE);
+      }
+
     if (change != verify_change)
       {
 	GString *s;
@@ -1671,8 +1676,6 @@ verify_tree_get_change_results (GtkCssProvider *provider,
 	g_warning (s->str);
 	g_string_free (s, TRUE);
       }
-
-    g_ptr_array_free (tree_rules, TRUE);
   }
 #endif
 }
@@ -1711,6 +1714,8 @@ gtk_css_provider_get_style_property (GtkStyleProvider *provider,
     }
 
   tree_rules = _gtk_css_selector_tree_match_all (priv->tree, &matcher);
+  if (tree_rules)
+    {
       verify_tree_match_results (css_provider, &matcher, tree_rules);
 
       prop_name = g_strdup_printf ("-%s-%s",
@@ -1735,12 +1740,8 @@ gtk_css_provider_get_style_property (GtkStyleProvider *provider,
                                                  val->section,
                                                  val->section != NULL ? gtk_css_section_get_file (val->section) : NULL,
                                                  val->value);
-
-	      found = _gtk_css_style_funcs_parse_value (value,
-					                scanner->parser);
-
+                  found = _gtk_css_style_funcs_parse_value (value, scanner->parser);
                   gtk_css_scanner_destroy (scanner);
-
 	          break;
                 }
             }
@@ -1751,6 +1752,8 @@ gtk_css_provider_get_style_property (GtkStyleProvider *provider,
 
       g_free (prop_name);
       g_ptr_array_free (tree_rules, TRUE);
+    }
+
   gtk_widget_path_unref (path);
 
   return found;
@@ -1797,6 +1800,8 @@ gtk_css_style_provider_lookup (GtkStyleProviderPrivate *provider,
   priv = css_provider->priv;
 
   tree_rules = _gtk_css_selector_tree_match_all (priv->tree, matcher);
+  if (tree_rules)
+    {
       verify_tree_match_results (css_provider, matcher, tree_rules);
 
       for (i = tree_rules->len - 1; i >= 0; i--)
@@ -1829,6 +1834,7 @@ gtk_css_style_provider_lookup (GtkStyleProviderPrivate *provider,
         }
 
       g_ptr_array_free (tree_rules, TRUE);
+    }
 
   if (change)
     {

gtk/gtkcssselector.c

@@ -140,9 +140,27 @@ gtk_css_selector_tree_get_matches (const GtkCssSelectorTree *tree)
   return (gpointer *) ((guint8 *)tree + tree->matches_offset);
 }
 
+static void
+g_ptr_array_insert_sorted (GPtrArray *array,
+                           gpointer   data)
+{
+  gint i;
+
+  for (i = 0; i < array->len; i++)
+    {
+      if (data == array->pdata[i])
+        return;
+
+      if (data < array->pdata[i])
+        break;
+    }
+
+  g_ptr_array_insert (array, i, data);
+}
+
 static void
 gtk_css_selector_tree_found_match (const GtkCssSelectorTree  *tree,
-				   GHashTable *res)
+				   GPtrArray                **array)
 {
   int i;
   gpointer *matches;
@@ -150,8 +168,11 @@ gtk_css_selector_tree_found_match (const GtkCssSelectorTree *tree,
   matches = gtk_css_selector_tree_get_matches (tree);
   if (matches)
     {
+      if (!*array)
+        *array = g_ptr_array_sized_new (16);
+
       for (i = 0; matches[i] != NULL; i++)
-	g_hash_table_insert (res, matches[i], matches[i]);
+        g_ptr_array_insert_sorted (*array, matches[i]);
     }
 }
 
@@ -1714,18 +1735,6 @@ gtk_css_selectors_skip_initial_selector (GtkCssSelector *selector, const GtkCssS
   return (GtkCssSelector *)gtk_css_selector_previous (selector);
 }
 
-static int
-direct_ptr_compare (const void *_a, const void *_b)
-{
-  gpointer *a = (gpointer *)_a;
-  gpointer *b = (gpointer *)_b;
-  if (*a < *b)
-    return -1;
-  else if (*a == *b)
-    return 0;
-  return 1;
-}
-
 static gboolean
 gtk_css_selector_tree_match_foreach (const GtkCssSelector *selector,
                                      const GtkCssMatcher  *matcher,
@@ -1751,28 +1760,13 @@ GPtrArray *
 _gtk_css_selector_tree_match_all (const GtkCssSelectorTree *tree,
 				  const GtkCssMatcher *matcher)
 {
-  GHashTable *res;
-  GPtrArray *array;
-  GHashTableIter iter;
-  gpointer key;
+  GPtrArray *array = NULL;
 
   update_type_references ();
 
-  res = g_hash_table_new (g_direct_hash, g_direct_equal);
-
   for (; tree != NULL;
        tree = gtk_css_selector_tree_get_sibling (tree))
-    gtk_css_selector_foreach (&tree->selector, matcher, gtk_css_selector_tree_match_foreach, res);
-
-  array = g_ptr_array_sized_new (g_hash_table_size (res));
-
-  g_hash_table_iter_init (&iter, res);
-  while (g_hash_table_iter_next (&iter, &key, NULL))
-    g_ptr_array_add (array, key);
-
-  g_hash_table_destroy (res);
-
-  qsort (array->pdata, array->len, sizeof (gpointer), direct_ptr_compare);
+    gtk_css_selector_foreach (&tree->selector, matcher, gtk_css_selector_tree_match_foreach, &array);
 
   return array;
 }