cssnode: Split out a function

So far the vfunc is kinda quirky (the path argument is an out argument
for something you have to free when you're done with the matcher), but
  I'm about to change that.

gtk/gtkcssmatcherprivate.h

@@ -24,7 +24,6 @@
 
 G_BEGIN_DECLS
 
-typedef union _GtkCssMatcher GtkCssMatcher;
 typedef struct _GtkCssMatcherSuperset GtkCssMatcherSuperset;
 typedef struct _GtkCssMatcherWidgetPath GtkCssMatcherWidgetPath;
 typedef struct _GtkCssMatcherClass GtkCssMatcherClass;

gtk/gtkcssnode.c

@@ -192,9 +192,7 @@ gtk_css_node_update_style (GtkCssNode       *cssnode,
   if (result)
     return g_object_ref (result);
 
-  path = gtk_css_node_create_widget_path (cssnode);
-
-  if (!_gtk_css_matcher_init (&matcher, path))
+  if (!gtk_css_node_init_matcher (cssnode, &matcher, &path))
     {
       g_assert_not_reached ();
     }
@@ -205,7 +203,8 @@ gtk_css_node_update_style (GtkCssNode       *cssnode,
                                             &matcher,
                                             parent);
 
-  gtk_widget_path_free (path);
+  if (path)
+    gtk_widget_path_free (path);
 
   store_in_global_parent_cache (cssnode, parent, decl, style);
 
@@ -228,9 +227,7 @@ gtk_css_node_create_style (GtkCssNode *cssnode)
   if (style)
     return g_object_ref (style);
 
-  path = gtk_css_node_create_widget_path (cssnode);
-
-  if (_gtk_css_matcher_init (&matcher, path))
+  if (gtk_css_node_init_matcher (cssnode, &matcher, &path))
     style = gtk_css_static_style_new_compute (gtk_css_node_get_style_provider (cssnode),
                                               &matcher,
                                               parent);
@@ -239,7 +236,8 @@ gtk_css_node_create_style (GtkCssNode *cssnode)
                                               NULL,
                                               parent);
 
-  gtk_widget_path_free (path);
+  if (path)
+    gtk_widget_path_free (path);
 
   store_in_global_parent_cache (cssnode, parent, decl, style);
 
@@ -298,6 +296,32 @@ gtk_css_node_real_validate (GtkCssNode       *cssnode,
   return _gtk_bitmask_new ();
 }
 
+gboolean
+gtk_css_node_real_init_matcher (GtkCssNode     *cssnode,
+                                GtkCssMatcher  *matcher,
+                                GtkWidgetPath **path_out)
+{
+  GtkWidgetPath *path;
+  
+  path = gtk_css_node_create_widget_path (cssnode);
+
+  if (!_gtk_css_matcher_init (matcher, path))
+    {
+      gtk_widget_path_free (path);
+      return FALSE;
+    }
+
+  if (path_out == NULL)
+    {
+      gtk_widget_path_free (path);
+      g_assert_not_reached ();
+      return FALSE;
+    }
+
+  *path_out = path;
+  return TRUE;
+}
+
 static GtkWidgetPath *
 gtk_css_node_real_create_widget_path (GtkCssNode *cssnode)
 {
@@ -332,6 +356,7 @@ gtk_css_node_class_init (GtkCssNodeClass *klass)
   klass->validate = gtk_css_node_real_validate;
   klass->queue_validate = gtk_css_node_real_queue_validate;
   klass->dequeue_validate = gtk_css_node_real_dequeue_validate;
+  klass->init_matcher = gtk_css_node_real_init_matcher;
   klass->create_widget_path = gtk_css_node_real_create_widget_path;
   klass->get_widget_path = gtk_css_node_real_get_widget_path;
   klass->get_style_provider = gtk_css_node_real_get_style_provider;
@@ -693,6 +718,17 @@ gtk_css_node_validate (GtkCssNode            *cssnode,
   _gtk_bitmask_free (changes);
 }
 
+gboolean
+gtk_css_node_init_matcher (GtkCssNode     *cssnode,
+                           GtkCssMatcher  *matcher,
+                           GtkWidgetPath **path_out)
+{
+  if (path_out)
+    *path_out = NULL;
+
+  return GTK_CSS_NODE_GET_CLASS (cssnode)->init_matcher (cssnode, matcher, path_out);
+}
+
 GtkWidgetPath *
 gtk_css_node_create_widget_path (GtkCssNode *cssnode)
 {

gtk/gtkcssnodeprivate.h

@@ -19,7 +19,8 @@
 #define __GTK_CSS_NODE_PRIVATE_H__
 
 #include "gtkcssnodedeclarationprivate.h"
-#include "gtkcssstyleprivate.h"
+#include "gtkbitmaskprivate.h"
+#include "gtkcsstypesprivate.h"
 
 G_BEGIN_DECLS
 
@@ -56,6 +57,9 @@ struct _GtkCssNodeClass
 {
   GObjectClass object_class;
 
+  gboolean              (* init_matcher)                (GtkCssNode            *cssnode,
+                                                         GtkCssMatcher         *matcher,
+                                                         GtkWidgetPath        **path);
   GtkWidgetPath *       (* create_widget_path)          (GtkCssNode            *cssnode);
   const GtkWidgetPath * (* get_widget_path)             (GtkCssNode            *cssnode);
   GtkStyleProviderPrivate *(* get_style_provider)       (GtkCssNode            *cssnode);
@@ -129,6 +133,10 @@ void                    gtk_css_node_validate           (GtkCssNode            *
                                                          const GtkBitmask      *parent_changes);
 void                    gtk_css_node_set_invalid        (GtkCssNode            *node,
                                                          gboolean               invalid);
+
+gboolean                gtk_css_node_init_matcher       (GtkCssNode            *cssnode,
+                                                         GtkCssMatcher         *matcher,
+                                                         GtkWidgetPath        **path);
 GtkWidgetPath *         gtk_css_node_create_widget_path (GtkCssNode            *cssnode);
 const GtkWidgetPath *   gtk_css_node_get_widget_path    (GtkCssNode            *cssnode);
 GtkStyleProviderPrivate *gtk_css_node_get_style_provider(GtkCssNode            *cssnode);

gtk/gtkcsstypesprivate.h

@@ -23,7 +23,8 @@
 
 G_BEGIN_DECLS
 
-/* forward declaration for GtkCssValue */
+typedef union _GtkCssMatcher GtkCssMatcher;
+typedef struct _GtkCssNode GtkCssNode;
 typedef struct _GtkCssStyle GtkCssStyle;
 typedef struct _GtkStyleProviderPrivate GtkStyleProviderPrivate; /* dummy typedef */