/*
 * GTK - The GIMP Toolkit
 * Copyright (C) 1998, 1999 Red Hat, Inc.
 * All rights reserved.
 *
 * This Library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This Library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with the Gnome Library; see the file COPYING.LIB.  If not,
 * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Author: James Henstridge <james@daa.com.au>
 *
 * Modified by the GTK+ Team and others 2003.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

#include <config.h>

#include <string.h>
#include "gtkmenumerge.h"
#include "gtktoolbar.h"
#include "gtkseparatortoolitem.h"
#include "gtkmenushell.h"
#include "gtkmenu.h"
#include "gtkmenubar.h"
#include "gtkseparatormenuitem.h"
#include "gtkintl.h"

#undef DEBUG_MENU_MERGE

typedef enum 
{
  GTK_MENU_MERGE_UNDECIDED,
  GTK_MENU_MERGE_ROOT,
  GTK_MENU_MERGE_MENUBAR,
  GTK_MENU_MERGE_MENU,
  GTK_MENU_MERGE_TOOLBAR,
  GTK_MENU_MERGE_MENU_PLACEHOLDER,
  GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER,
  GTK_MENU_MERGE_POPUPS,
  GTK_MENU_MERGE_MENUITEM,
  GTK_MENU_MERGE_TOOLITEM,
  GTK_MENU_MERGE_SEPARATOR,
} GtkMenuMergeNodeType;


typedef struct _GtkMenuMergeNode  GtkMenuMergeNode;

struct _GtkMenuMergeNode {
  GtkMenuMergeNodeType type;

  const gchar *name;

  GQuark action_name;
  GtkAction *action;
  GtkWidget *proxy;
  GtkWidget *extra; /*GtkMenu for submenus, second separator for placeholders*/

  GList *uifiles;

  guint dirty : 1;
};

#define GTK_MENU_MERGE_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GTK_TYPE_MENU_MERGE, GtkMenuMergePrivate))

struct _GtkMenuMergePrivate 
{
  GtkAccelGroup *accel_group;

  GNode *root_node;
  GList *action_groups;

  guint last_merge_id;

  guint update_tag;  
};

#define NODE_INFO(node) ((GtkMenuMergeNode *)node->data)

typedef struct _NodeUIReference NodeUIReference;

struct _NodeUIReference 
{
  guint merge_id;
  GQuark action_quark;
};

static void   gtk_menu_merge_class_init    (GtkMenuMergeClass *class);
static void   gtk_menu_merge_init          (GtkMenuMerge *merge);

static void   gtk_menu_merge_queue_update  (GtkMenuMerge *self);
static void   gtk_menu_merge_dirty_all     (GtkMenuMerge *self);

static GNode *get_child_node               (GtkMenuMerge *self, GNode *parent,
					    const gchar *childname,
					    gint childname_length,
					    GtkMenuMergeNodeType node_type,
					    gboolean create, gboolean top);
static GNode *gtk_menu_merge_get_node      (GtkMenuMerge *self,
					    const gchar *path,
					    GtkMenuMergeNodeType node_type,
					    gboolean create);
static guint gtk_menu_merge_next_merge_id  (GtkMenuMerge *self);

static void  gtk_menu_merge_node_prepend_ui_reference (GtkMenuMergeNode *node,
						       guint merge_id,
						       GQuark action_quark);
static void  gtk_menu_merge_node_remove_ui_reference  (GtkMenuMergeNode *node,
						       guint merge_id);
static void  gtk_menu_merge_ensure_update  (GtkMenuMerge *self);


enum 
{
  ADD_WIDGET,
  REMOVE_WIDGET,
  LAST_SIGNAL
};

static guint merge_signals[LAST_SIGNAL] = { 0 };

static GMemChunk *merge_node_chunk = NULL;

GType
gtk_menu_merge_get_type (void)
{
  static GtkType type = 0;

  if (!type)
    {
      static const GTypeInfo type_info =
      {
        sizeof (GtkMenuMergeClass),
        (GBaseInitFunc) NULL,
        (GBaseFinalizeFunc) NULL,
        (GClassInitFunc) gtk_menu_merge_class_init,
        (GClassFinalizeFunc) NULL,
        NULL,
        
        sizeof (GtkMenuMerge),
        0, /* n_preallocs */
        (GInstanceInitFunc) gtk_menu_merge_init,
      };

      type = g_type_register_static (G_TYPE_OBJECT,
				     "GtkMenuMerge",
				     &type_info, 0);
    }
  return type;
}

static void
gtk_menu_merge_class_init (GtkMenuMergeClass *klass)
{
  GObjectClass *gobject_class;

  gobject_class = G_OBJECT_CLASS (klass);

  if (!merge_node_chunk)
    merge_node_chunk = g_mem_chunk_create (GtkMenuMergeNode, 64,
					   G_ALLOC_AND_FREE);

  merge_signals[ADD_WIDGET] =
    g_signal_new ("add_widget",
		  G_OBJECT_CLASS_TYPE (klass),
		  G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
		  G_STRUCT_OFFSET (GtkMenuMergeClass, add_widget), NULL, NULL,
		  g_cclosure_marshal_VOID__OBJECT,
		  G_TYPE_NONE, 1,
		  GTK_TYPE_WIDGET);
  merge_signals[REMOVE_WIDGET] =
    g_signal_new ("remove_widget",
		  G_OBJECT_CLASS_TYPE (klass),
		  G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
		  G_STRUCT_OFFSET (GtkMenuMergeClass, remove_widget), NULL, NULL,
		  g_cclosure_marshal_VOID__OBJECT,
		  G_TYPE_NONE, 1,
		  GTK_TYPE_WIDGET);  
  
  g_type_class_add_private (gobject_class, sizeof (GtkMenuMergePrivate));
}


static void
gtk_menu_merge_init (GtkMenuMerge *self)
{
  guint merge_id;
  GNode *node;

  self->private_data = GTK_MENU_MERGE_GET_PRIVATE (self);

  self->private_data->accel_group = gtk_accel_group_new ();

  self->private_data->root_node = NULL;
  self->private_data->action_groups = NULL;

  self->private_data->last_merge_id = 0;


  merge_id = gtk_menu_merge_next_merge_id (self);
  node = get_child_node (self, NULL, "Root", 4,
			GTK_MENU_MERGE_ROOT, TRUE, FALSE);
  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (node), merge_id, 0);
  node = get_child_node (self, self->private_data->root_node, "popups", 6,
			 GTK_MENU_MERGE_POPUPS, TRUE, FALSE);
  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (node), merge_id, 0);
}


/**
 * gtk_menu_merge_new:
 * 
 * Creates a new menu merge object.
 * 
 * Return value: a new menu merge object.
 *
 * Since: 2.4
 **/
GtkMenuMerge*
gtk_menu_merge_new (void)
{
  return g_object_new (GTK_TYPE_MENU_MERGE, NULL);
}


/**
 * gtk_menu_merge_insert_action_group:
 * @self: a #GtkMenuMerge object
 * @action_group: the action group to be inserted
 * @pos: the position at which the group will be inserted
 * 
 * Inserts an action group into the list of action groups associated with @self.
 *
 * Since: 2.4
 **/
void
gtk_menu_merge_insert_action_group (GtkMenuMerge   *self,
				    GtkActionGroup *action_group, 
				    gint            pos)
{
  g_return_if_fail (GTK_IS_MENU_MERGE (self));
  g_return_if_fail (GTK_IS_ACTION_GROUP (action_group));
  g_return_if_fail (g_list_find (self->private_data->action_groups, action_group) == NULL);

  g_object_ref (action_group);
  self->private_data->action_groups = g_list_insert (self->private_data->action_groups, action_group, pos);

  /* dirty all nodes, as action bindings may change */
  gtk_menu_merge_dirty_all (self);
}

/**
 * gtk_menu_merge_remove_action_group:
 * @self: a #GtkMenuMerge object
 * @action_group: the action group to be removed
 * 
 * Removes an action group from the list of action groups associated with @self.
 *
 * Since: 2.4
 **/
void
gtk_menu_merge_remove_action_group (GtkMenuMerge   *self,
				    GtkActionGroup *action_group)
{
  g_return_if_fail (GTK_IS_MENU_MERGE (self));
  g_return_if_fail (GTK_IS_ACTION_GROUP (action_group));
  g_return_if_fail (g_list_find (self->private_data->action_groups, 
				 action_group) != NULL);

  self->private_data->action_groups =
    g_list_remove (self->private_data->action_groups, action_group);
  g_object_unref (action_group);

  /* dirty all nodes, as action bindings may change */
  gtk_menu_merge_dirty_all (self);
}

/**
 * gtk_menu_merge_get_action_groups:
 * @self: a #GtkMenuMerge object
 * 
 * Returns the list of action groups associated with @self.
 *
 * Return value: a #GList of action groups. The list is owned by GTK+ 
 *   and should not be modified.
 *
 * Since: 2.4
 **/
GList *
gtk_menu_merge_get_action_groups (GtkMenuMerge   *self)
{
  g_return_val_if_fail (GTK_IS_MENU_MERGE (self), NULL);

  return self->private_data->action_groups;
}

/**
 * gtk_menu_merge_get_accel_group:
 * @self: a #GtkMenuMerge object
 * 
 * Returns the #GtkAccelGroup associated with @self.
 *
 * Return value: the #GtkAccelGroup.
 *
 * Since: 2.4
 **/
GtkAccelGroup *
gtk_menu_merge_get_accel_group (GtkMenuMerge   *self)
{
  g_return_val_if_fail (GTK_IS_MENU_MERGE (self), NULL);

  return self->private_data->accel_group;
}

/**
 * gtk_menu_merge_get_widget:
 * @self: a #GtkMenuMerge
 * @path: a path
 * 
 * Looks up a widget by following a path. The path consists of the names specified
 * in the XML description of the UI. separated by '/'. Elements which don't have
 * a name attribute in the XML (e.g. &lt;popups&gt;) can be addressed by their
 * XML element name (e.g. "popups").
 * 
 * Return value: the widget found by following the path, or %NULL if no widget
 *   was found.
 *
 * Since: 2.4
 **/
GtkWidget *
gtk_menu_merge_get_widget (GtkMenuMerge *self, 
			   const gchar  *path)
{
  GNode *node;

  /* ensure that there are no pending updates before we get the
   * widget */
  gtk_menu_merge_ensure_update (self);

  node = gtk_menu_merge_get_node (self, path, GTK_MENU_MERGE_UNDECIDED, FALSE);

  if (node == NULL)
    return NULL;

  return NODE_INFO (node)->proxy;
}

static GNode *
get_child_node (GtkMenuMerge        *self, 
		GNode               *parent,
		const gchar         *childname, 
		gint                 childname_length,
		GtkMenuMergeNodeType node_type,
		gboolean             create, 
		gboolean             top)
{
  GNode *child = NULL;

  g_return_val_if_fail (parent == NULL ||
			(NODE_INFO (parent)->type != GTK_MENU_MERGE_MENUITEM &&
			 NODE_INFO (parent)->type != GTK_MENU_MERGE_TOOLITEM), 
			NULL);

  if (parent)
    {
      if (childname)
	{
	  for (child = parent->children; child != NULL; child = child->next)
	    {
	      if (strlen (NODE_INFO (child)->name) == childname_length &&
		  !strncmp (NODE_INFO (child)->name, childname, childname_length))
		{
		  /* if undecided about node type, set it */
		  if (NODE_INFO (child)->type == GTK_MENU_MERGE_UNDECIDED)
		    NODE_INFO (child)->type = node_type;
		  
		  /* warn about type mismatch */
		  if (NODE_INFO (child)->type != GTK_MENU_MERGE_UNDECIDED &&
		      node_type != GTK_MENU_MERGE_UNDECIDED &&
		      NODE_INFO (child)->type != node_type)
		    g_warning ("node type doesn't match %d (%s is type %d)",
			       node_type, 
			       NODE_INFO (child)->name,
			       NODE_INFO (child)->type);
		  
		  return child;
		}
	    }
	}
      if (!child && create)
	{
	  GtkMenuMergeNode *mnode;
	  
	  mnode = g_chunk_new0 (GtkMenuMergeNode, merge_node_chunk);
	  mnode->type = node_type;
	  mnode->name = g_strndup (childname, childname_length);
	  mnode->dirty = TRUE;

	  if (top)
	    child = g_node_prepend_data (parent, mnode);
	  else
	    child = g_node_append_data (parent, mnode);
	}
    }
  else
    {
      /* handle root node */
      if (self->private_data->root_node)
	{
	  child = self->private_data->root_node;
	  if (strncmp (NODE_INFO (child)->name, childname, childname_length) != 0)
	    g_warning ("root node name '%s' doesn't match '%s'",
		       childname, NODE_INFO (child)->name);
	  if (NODE_INFO (child)->type != GTK_MENU_MERGE_ROOT)
	    g_warning ("base element must be of type ROOT");
	}
      else if (create)
	{
	  GtkMenuMergeNode *mnode;

	  mnode = g_chunk_new0 (GtkMenuMergeNode, merge_node_chunk);
	  mnode->type = node_type;
	  mnode->name = g_strndup (childname, childname_length);
	  mnode->dirty = TRUE;
	  
	  child = self->private_data->root_node = g_node_new (mnode);
	}
    }

  return child;
}

static GNode *
gtk_menu_merge_get_node (GtkMenuMerge        *self, 
			 const gchar         *path,
			 GtkMenuMergeNodeType node_type, 
			 gboolean             create)
{
  const gchar *pos, *end;
  GNode *parent, *node;
  
  end = path + strlen (path);
  pos = path;
  parent = node = NULL;
  while (pos < end)
    {
      const gchar *slash;
      gsize length;

      slash = strchr (pos, '/');
      if (slash)
	length = slash - pos;
      else
	length = strlen (pos);

      node = get_child_node (self, parent, pos, length, GTK_MENU_MERGE_UNDECIDED,
			     create, FALSE);
      if (!node)
	return NULL;
      
      pos += length + 1; /* move past the node name and the slash too */
      parent = node;
    }

  if (NODE_INFO (node)->type == GTK_MENU_MERGE_UNDECIDED)
    NODE_INFO (node)->type = node_type;
  return node;
}

static guint
gtk_menu_merge_next_merge_id (GtkMenuMerge *self)
{
  self->private_data->last_merge_id++;

  return self->private_data->last_merge_id;
}

static void
gtk_menu_merge_node_prepend_ui_reference (GtkMenuMergeNode *node,
					  guint             merge_id, 
					  GQuark            action_quark)
{
  NodeUIReference *reference;

  reference = g_new (NodeUIReference, 1);
  reference->action_quark = action_quark;
  reference->merge_id = merge_id;

  /* Prepend the reference */
  node->uifiles = g_list_prepend (node->uifiles, reference);

  node->dirty = TRUE;
}

static void
gtk_menu_merge_node_remove_ui_reference (GtkMenuMergeNode *node,
					 guint             merge_id)
{
  GList *p;
  
  for (p = node->uifiles; p != NULL; p = p->next)
    {
      NodeUIReference *reference = p->data;
      
      if (reference->merge_id == merge_id)
	{
	  node->uifiles = g_list_remove_link (node->uifiles, p);
	  node->dirty = TRUE;
	  g_free (reference);

	  break;
	}
    }
}

/* -------------------- The UI file parser -------------------- */

typedef enum
{
  STATE_START,
  STATE_ROOT,
  STATE_MENU,
  STATE_TOOLBAR,
  STATE_POPUPS,
  STATE_MENUITEM,
  STATE_TOOLITEM,
  STATE_END
} ParseState;

typedef struct _ParseContext ParseContext;
struct _ParseContext
{
  ParseState state;
  ParseState prev_state;

  GtkMenuMerge *self;

  GNode *current;

  guint merge_id;
};

static void
start_element_handler (GMarkupParseContext *context,
		       const gchar         *element_name,
		       const gchar        **attribute_names,
		       const gchar        **attribute_values,
		       gpointer             user_data,
		       GError             **error)
{
  ParseContext *ctx = user_data;
  GtkMenuMerge *self = ctx->self;

  gint i;
  const gchar *node_name;
  GQuark verb_quark;
  gboolean top;

  gboolean raise_error = TRUE;
  gchar *error_attr = NULL;

  /* work out a name for this node.  Either the name attribute, or
   * element name */
  node_name = element_name;
  verb_quark = 0;
  top = FALSE;
  for (i = 0; attribute_names[i] != NULL; i++)
    {
      if (!strcmp (attribute_names[i], "name"))
	{
	  node_name = attribute_values[i];
	}
      else if (!strcmp (attribute_names[i], "verb"))
	{
	  verb_quark = g_quark_from_string (attribute_values[i]);
	}
      else if (!strcmp (attribute_names[i], "pos"))
	{
	  top = !strcmp (attribute_values[i], "top");
	}
    }
  /* if no verb, then set it to the node's name */
  if (verb_quark == 0)
    verb_quark = g_quark_from_string (node_name);

  switch (element_name[0])
    {
    case 'R':
      if (ctx->state == STATE_START && !strcmp (element_name, "Root"))
	{
	  ctx->state = STATE_ROOT;
	  ctx->current = self->private_data->root_node;
	  raise_error = FALSE;

	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	}
      break;
    case 'm':
      if (ctx->state == STATE_ROOT && !strcmp (element_name, "menu"))
	{
	  ctx->state = STATE_MENU;
	  ctx->current = get_child_node (self, ctx->current,
					 node_name, strlen (node_name),
					 GTK_MENU_MERGE_MENUBAR,
					 TRUE, FALSE);
	  if (NODE_INFO (ctx->current)->action_name == 0)
	    NODE_INFO (ctx->current)->action_name = verb_quark;

	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (ctx->current)->dirty = TRUE;

	  raise_error = FALSE;
	}
      else if (ctx->state == STATE_MENU && !strcmp (element_name, "menuitem"))
	{
	  GNode *node;

	  ctx->state = STATE_MENUITEM;
	  node = get_child_node (self, ctx->current,
				 node_name, strlen (node_name),
				 GTK_MENU_MERGE_MENUITEM,
				 TRUE, top);
	  if (NODE_INFO (node)->action_name == 0)
	    NODE_INFO (node)->action_name = verb_quark;
	  
	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (node),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (node)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      break;
    case 'd':
      if (ctx->state == STATE_ROOT && !strcmp (element_name, "dockitem"))
	{
	  ctx->state = STATE_TOOLBAR;
	  ctx->current = get_child_node (self, ctx->current,
					 node_name, strlen (node_name),
					 GTK_MENU_MERGE_TOOLBAR,
					 TRUE, FALSE);
	  if (NODE_INFO (ctx->current)->action_name == 0)
	    NODE_INFO (ctx->current)->action_name = verb_quark;
	  
	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (ctx->current)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      break;
    case 'p':
      if (ctx->state == STATE_ROOT && !strcmp (element_name, "popups"))
	{
	  ctx->state = STATE_POPUPS;
	  ctx->current = get_child_node (self, ctx->current,
					 node_name, strlen (node_name),
					 GTK_MENU_MERGE_POPUPS,
					 TRUE, FALSE);
	  
	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (ctx->current)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      else if (ctx->state == STATE_POPUPS && !strcmp (element_name, "popup"))
	{
	  ctx->state = STATE_MENU;
	  ctx->current = get_child_node (self, ctx->current,
					 node_name, strlen (node_name),
					 GTK_MENU_MERGE_MENU,
					 TRUE, FALSE);
	  if (NODE_INFO (ctx->current)->action_name == 0)
	    NODE_INFO (ctx->current)->action_name = verb_quark;
	  
	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (ctx->current)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      else if ((ctx->state == STATE_MENU || ctx->state == STATE_TOOLBAR) &&
	       !strcmp (element_name, "placeholder"))
	{
	  if (ctx->state == STATE_MENU)
	    ctx->current = get_child_node (self, ctx->current,
					   node_name, strlen (node_name),
					   GTK_MENU_MERGE_MENU_PLACEHOLDER,
					   TRUE, top);
	  else
	    ctx->current = get_child_node (self, ctx->current,
					   node_name, strlen (node_name),
					   GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER,
					   TRUE, top);
	  
	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (ctx->current)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      break;
    case 's':
      if (ctx->state == STATE_MENU && !strcmp (element_name, "submenu"))
	{
	  ctx->state = STATE_MENU;
	  ctx->current = get_child_node (self, ctx->current,
					 node_name, strlen (node_name),
					 GTK_MENU_MERGE_MENU,
					 TRUE, top);
	  if (NODE_INFO (ctx->current)->action_name == 0)
	    NODE_INFO (ctx->current)->action_name = verb_quark;

	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (ctx->current),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (ctx->current)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      else if ((ctx->state == STATE_MENU || ctx->state == STATE_TOOLBAR) &&
	       !strcmp (element_name, "separator"))
	{
	  GNode *node;

	  if (ctx->state == STATE_MENU)
	    ctx->state = STATE_MENUITEM;
	  else
	    ctx->state = STATE_TOOLITEM;
	  node = get_child_node (self, ctx->current,
				 node_name, strlen (node_name),
				 GTK_MENU_MERGE_SEPARATOR,
				 TRUE, top);
	  if (NODE_INFO (node)->action_name == 0)
	    NODE_INFO (node)->action_name = verb_quark;

	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (node),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (node)->dirty = TRUE;
	  
	  raise_error = FALSE;
	}
      break;
    case 't':
      if (ctx->state == STATE_TOOLBAR && !strcmp (element_name, "toolitem"))
	{
	  GNode *node;

	  ctx->state = STATE_TOOLITEM;
	  node = get_child_node (self, ctx->current,
				node_name, strlen (node_name),
				 GTK_MENU_MERGE_TOOLITEM,
				 TRUE, top);
	  if (NODE_INFO (node)->action_name == 0)
	    NODE_INFO (node)->action_name = verb_quark;
	  
	  gtk_menu_merge_node_prepend_ui_reference (NODE_INFO (node),
						    ctx->merge_id, verb_quark);
	  NODE_INFO (node)->dirty = TRUE;

	  raise_error = FALSE;
	}
      break;
    default:
      break;
    }
  if (raise_error)
    {
      gint line_number, char_number;
 
      g_markup_parse_context_get_position (context,
					   &line_number, &char_number);
      if (error_attr)
	g_set_error (error,
		     G_MARKUP_ERROR,
		     G_MARKUP_ERROR_UNKNOWN_ATTRIBUTE,
		     _("Unknown attribute '%s' on line %d char %d"),
		     error_attr,
		     line_number, char_number);
      else
	g_set_error (error,
		     G_MARKUP_ERROR,
		     G_MARKUP_ERROR_UNKNOWN_ELEMENT,
		     _("Unknown tag '%s' on line %d char %d"),
		     element_name,
		     line_number, char_number);
    }
}

static void
end_element_handler (GMarkupParseContext *context,
		     const gchar         *element_name,
		     gpointer             user_data,
		     GError             **error)
{
  ParseContext *ctx = user_data;
  GtkMenuMerge *self = ctx->self;

  switch (ctx->state)
    {
    case STATE_START:
      g_warning ("shouldn't get any end tags in start state");
      /* should we GError here? */
      break;
    case STATE_ROOT:
      if (ctx->current != self->private_data->root_node)
	g_warning ("we are in STATE_ROOT, but the current node isn't the root");
      ctx->current = NULL;
      ctx->state = STATE_END;
      break;
    case STATE_MENU:
      ctx->current = ctx->current->parent;
      if (NODE_INFO (ctx->current)->type == GTK_MENU_MERGE_ROOT) /* menubar */
	ctx->state = STATE_ROOT;
      else if (NODE_INFO (ctx->current)->type == GTK_MENU_MERGE_POPUPS) /* popup */
	ctx->state = STATE_POPUPS;
      /* else, stay in STATE_MENU state */
      break;
    case STATE_TOOLBAR:
      ctx->current = ctx->current->parent;
      /* we conditionalise this test, in case we are closing off a
       * placeholder */
      if (NODE_INFO (ctx->current)->type == GTK_MENU_MERGE_ROOT)
	ctx->state = STATE_ROOT;
      /* else, stay in STATE_TOOLBAR state */
      break;
    case STATE_POPUPS:
      ctx->current = ctx->current->parent;
      ctx->state = STATE_ROOT;
      break;
    case STATE_MENUITEM:
      ctx->state = STATE_MENU;
      break;
    case STATE_TOOLITEM:
      ctx->state = STATE_TOOLBAR;
      break;
    case STATE_END:
      g_warning ("shouldn't get any end tags at this point");
      /* should do an error here */
      break;
    }
}

static void
cleanup (GMarkupParseContext *context,
	 GError              *error,
	 gpointer             user_data)
{
  ParseContext *ctx = user_data;
  GtkMenuMerge *self = ctx->self;

  ctx->current = NULL;
  /* should also walk through the tree and get rid of nodes related to
   * this UI file's tag */

  gtk_menu_merge_remove_ui (self, ctx->merge_id);
}

static GMarkupParser ui_parser = {
  start_element_handler,
  end_element_handler,
  NULL,
  NULL,
  cleanup
};


/**
 * gtk_menu_merge_add_ui_from_string:
 * @self: a #GtkMenuMerge object
 * @buffer: the string to parse
 * @length: the length of @buffer (may be -1 if @buffer is nul-terminated)
 * @error: return location for an error
 * 
 * Parses a string containing a UI description and merge it with the current
 * contents of @self. FIXME: describe the XML format.
 * 
 * Return value: The merge id for the merged UI. The merge id can be used
 *   to unmerge the UI with gtk_menu_merge_remove_ui(). If an error occurred,
 *   the return value is 0.
 *
 * Since: 2.4
 **/
guint
gtk_menu_merge_add_ui_from_string (GtkMenuMerge *self,
				   const gchar  *buffer, 
				   gsize         length,
				   GError      **error)
{
  ParseContext ctx = { 0 };
  GMarkupParseContext *context;
  gboolean res = TRUE;

  g_return_val_if_fail (GTK_IS_MENU_MERGE (self), FALSE);
  g_return_val_if_fail (buffer != NULL, FALSE);

  ctx.state = STATE_START;
  ctx.self = self;
  ctx.current = NULL;
  ctx.merge_id = gtk_menu_merge_next_merge_id (self);

  context = g_markup_parse_context_new (&ui_parser, 0, &ctx, NULL);
  if (length < 0)
    length = strlen (buffer);

  if (g_markup_parse_context_parse (context, buffer, length, error))
    {
      if (!g_markup_parse_context_end_parse (context, error))
	res = FALSE;
    }
  else
    res = FALSE;

  g_markup_parse_context_free (context);

  gtk_menu_merge_queue_update (self);

  if (res)
    return ctx.merge_id;

  return 0;
}

/**
 * gtk_menu_merge_add_ui_from_file:
 * @self: a #GtkMenuMerge object
 * @filename: the name of the file to parse 
 * @error: return location for an error
 * 
 * Parses a file containing a UI description and merge it with the current
 * contents of @self. See gtk_menu_merge_add_ui_from_file().
 * 
 * Return value: The merge id for the merged UI. The merge id can be used
 *   to unmerge the UI with gtk_menu_merge_remove_ui(). If an error occurred,
 *   the return value is 0.
 *
 * Since: 2.4
 **/
guint
gtk_menu_merge_add_ui_from_file (GtkMenuMerge *self,
				 const gchar  *filename,
				 GError      **error)
{
  gchar *buffer;
  gint length;
  guint res;

  if (!g_file_get_contents (filename, &buffer, &length, error))
    return 0;

  res = gtk_menu_merge_add_ui_from_string (self, buffer, length, error);
  g_free (buffer);

  return res;
}

static gboolean
remove_ui (GNode   *node, 
	   gpointer user_data)
{
  guint merge_id = GPOINTER_TO_UINT (user_data);

  gtk_menu_merge_node_remove_ui_reference (NODE_INFO (node), merge_id);

  return FALSE; /* continue */
}

/**
 * gtk_menu_merge_remove_ui:
 * @self: a #GtkMenuMerge object
 * @merge_id: a merge id as returned by gtk_menu_merge_add_ui_from_string()
 * 
 * Unmerges the part of @self<!-- -->s content identified by @merge_id.
 **/
void
gtk_menu_merge_remove_ui (GtkMenuMerge *self, 
			  guint         merge_id)
{
  g_node_traverse (self->private_data->root_node, G_POST_ORDER, G_TRAVERSE_ALL, -1,
		   remove_ui, GUINT_TO_POINTER (merge_id));

  gtk_menu_merge_queue_update (self);
}

/* -------------------- Updates -------------------- */


static GtkAction *
get_action_by_name (GtkMenuMerge *merge, 
		    const char   *action_name)
{
  GList *tmp;

  if (!action_name)
    return NULL;
  
  /* lookup name */
  for (tmp = merge->private_data->action_groups; tmp != NULL; tmp = tmp->next)
    {
      GtkActionGroup *action_group = tmp->data;
      GtkAction *action;
      
      action = gtk_action_group_get_action (action_group, action_name);

      if (action)
	return action;
    }

  return NULL;
}

static gboolean
find_menu_position (GNode      *node, 
		    GtkWidget **menushell_p, 
		    gint       *pos_p)
{
  GtkWidget *menushell;
  gint pos;

  g_return_val_if_fail (node != NULL, FALSE);
  g_return_val_if_fail (NODE_INFO (node)->type == GTK_MENU_MERGE_MENU ||
			NODE_INFO (node)->type == GTK_MENU_MERGE_MENU_PLACEHOLDER ||
			NODE_INFO (node)->type == GTK_MENU_MERGE_MENUITEM ||
			NODE_INFO (node)->type == GTK_MENU_MERGE_SEPARATOR,
			FALSE);

  /* first sibling -- look at parent */
  if (node->prev == NULL)
    {
      GNode *parent;

      parent = node->parent;
      switch (NODE_INFO (parent)->type)
	{
	case GTK_MENU_MERGE_MENUBAR:
	  menushell = NODE_INFO (parent)->proxy;
	  pos = 0;
	  break;
	case GTK_MENU_MERGE_MENU:
	  menushell = NODE_INFO (parent)->proxy;
	  if (GTK_IS_MENU_ITEM (menushell))
	    menushell = gtk_menu_item_get_submenu (GTK_MENU_ITEM (menushell));
	  pos = 0;
	  break;
	case GTK_MENU_MERGE_MENU_PLACEHOLDER:
	  menushell = gtk_widget_get_parent (NODE_INFO (parent)->proxy);
	  g_return_val_if_fail (GTK_IS_MENU_SHELL (menushell), FALSE);
	  pos = g_list_index (GTK_MENU_SHELL (menushell)->children,
			      NODE_INFO (parent)->proxy) + 1;
	  break;
	default:
	  g_warning("%s: bad parent node type %d", G_STRLOC,
		    NODE_INFO (parent)->type);
	  return FALSE;
	}
    }
  else
    {
      GtkWidget *prev_child;
      GNode *sibling;

      sibling = node->prev;
      if (NODE_INFO (sibling)->type == GTK_MENU_MERGE_MENU_PLACEHOLDER)
	prev_child = NODE_INFO (sibling)->extra; /* second Separator */
      else
	prev_child = NODE_INFO (sibling)->proxy;

      g_return_val_if_fail (GTK_IS_WIDGET (prev_child), FALSE);
      menushell = gtk_widget_get_parent (prev_child);
      g_return_val_if_fail (GTK_IS_MENU_SHELL (menushell), FALSE);

      pos = g_list_index (GTK_MENU_SHELL (menushell)->children, prev_child) + 1;
    }

  if (menushell_p)
    *menushell_p = menushell;
  if (pos_p)
    *pos_p = pos;

  return TRUE;
}

static gboolean
find_toolbar_position (GNode      *node, 
		       GtkWidget **toolbar_p, 
		       gint       *pos_p)
{
  GtkWidget *toolbar;
  gint pos;

  g_return_val_if_fail (node != NULL, FALSE);
  g_return_val_if_fail (NODE_INFO (node)->type == GTK_MENU_MERGE_TOOLBAR ||
			NODE_INFO (node)->type == GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER ||
			NODE_INFO (node)->type == GTK_MENU_MERGE_TOOLITEM ||
			NODE_INFO (node)->type == GTK_MENU_MERGE_SEPARATOR,
			FALSE);

  /* first sibling -- look at parent */
  if (node->prev == NULL)
    {
      GNode *parent;

      parent = node->parent;
      switch (NODE_INFO (parent)->type)
	{
	case GTK_MENU_MERGE_TOOLBAR:
	  toolbar = NODE_INFO (parent)->proxy;
	  pos = 0;
	  break;
	case GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER:
	  toolbar = gtk_widget_get_parent (NODE_INFO (parent)->proxy);
	  g_return_val_if_fail (GTK_IS_TOOLBAR (toolbar), FALSE);
	  pos = gtk_toolbar_get_item_index (GTK_TOOLBAR (toolbar),
					    GTK_TOOL_ITEM (NODE_INFO (parent)->proxy)) + 1;
	  break;
	default:
	  g_warning ("%s: bad parent node type %d", G_STRLOC,
		     NODE_INFO (parent)->type);
	  return FALSE;
	}
    }
  else
    {
      GtkWidget *prev_child;
      GNode *sibling;

      sibling = node->prev;
      if (NODE_INFO (sibling)->type == GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER)
	prev_child = NODE_INFO (sibling)->extra; /* second Separator */
      else
	prev_child = NODE_INFO (sibling)->proxy;

      g_return_val_if_fail (GTK_IS_WIDGET (prev_child), FALSE);
      toolbar = gtk_widget_get_parent (prev_child);
      g_return_val_if_fail (GTK_IS_TOOLBAR (toolbar), FALSE);

      pos = gtk_toolbar_get_item_index (GTK_TOOLBAR (toolbar),
					GTK_TOOL_ITEM (prev_child)) + 1;
    }

  if (toolbar_p)
    *toolbar_p = toolbar;
  if (pos_p)
    *pos_p = pos;

  return TRUE;
}

static void
update_node (GtkMenuMerge *self, 
	     GNode        *node)
{
  GtkMenuMergeNode *info;
  GNode *child;
  GtkAction *action;
#ifdef DEBUG_MENU_MERGE
  GList *tmp;
#endif

  g_return_if_fail (node != NULL);
  g_return_if_fail (NODE_INFO (node) != NULL);

  info = NODE_INFO (node);

#ifdef DEBUG_MENU_MERGE
  g_print ("update_node name=%s dirty=%d (", info->name, info->dirty);
  for (tmp = info->uifiles; tmp != NULL; tmp = tmp->next)
    {
      NodeUIReference *ref = tmp->data;
      g_print("%s:%u", g_quark_to_string (ref->action_quark), ref->merge_id);
      if (tmp->next)
	g_print (", ");
    }
  g_print (")\n");
#endif

  if (NODE_INFO (node)->dirty)
    {
      const gchar *action_name;
      NodeUIReference *ref;

      if (info->uifiles == NULL) {
	/* We may need to remove this node.
	 * This must be done in post order
	 */
	goto recurse_children;
      }

      ref = info->uifiles->data;
      action_name = g_quark_to_string (ref->action_quark);
      action = get_action_by_name (self, action_name);

      NODE_INFO (node)->dirty = FALSE;

      /* Check if the node doesn't have an action and must have an action */
      if (action == NULL &&
	  info->type != GTK_MENU_MERGE_MENUBAR &&
	  info->type != GTK_MENU_MERGE_TOOLBAR &&
	  info->type != GTK_MENU_MERGE_SEPARATOR &&
	  info->type != GTK_MENU_MERGE_MENU_PLACEHOLDER &&
	  info->type != GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER)
	{
	  /* FIXME: Should we warn here? */
	  goto recurse_children;
	}

      /* If the widget already has a proxy and the action hasn't changed, then
       * we don't have to do anything.
       */
      if (info->proxy != NULL &&
	  action == info->action)
	{
	  goto recurse_children;
	}
      
      if (info->action)
	g_object_unref (info->action);
      info->action = action;
      if (info->action)
	g_object_ref (info->action);

      switch (info->type)
	{
	case GTK_MENU_MERGE_MENUBAR:
	  if (info->proxy == NULL)
	    {
	      info->proxy = gtk_menu_bar_new ();
	      gtk_widget_show (info->proxy);
	      g_signal_emit (self, merge_signals[ADD_WIDGET], 0, info->proxy);
	    }
	  break;
	case GTK_MENU_MERGE_MENU:
	  if (NODE_INFO (node->parent)->type == GTK_MENU_MERGE_POPUPS)
	    {
	      if (info->proxy == NULL) 
		{
		  GtkWidget *menu;
		  menu = gtk_menu_new ();
		  gtk_menu_set_accel_group (GTK_MENU (menu), self->private_data->accel_group);
		  info->proxy = menu;
		}
	    }
	  else
	    {
	      GtkWidget *prev_submenu = NULL;
	      /* remove the proxy if it is of the wrong type ... */
	      if (info->proxy &&  G_OBJECT_TYPE (info->proxy) !=
		  GTK_ACTION_GET_CLASS (info->action)->menu_item_type)
		{
		  prev_submenu = gtk_menu_item_get_submenu (GTK_MENU_ITEM (info->proxy));
		  if (prev_submenu)
		    {
		      g_object_ref (prev_submenu);
		      gtk_menu_item_set_submenu (GTK_MENU_ITEM (info->proxy),NULL);
		    }
		  gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
					info->proxy);
		  info->proxy = NULL;
		}
	      /* create proxy if needed ... */
	      if (info->proxy == NULL)
		{
		  GtkWidget *menushell;
		  gint pos;
		  
		  if (find_menu_position (node, &menushell, &pos))
		    {
		      GtkWidget *menu;
		      info->proxy = gtk_action_create_menu_item (info->action);
		      menu = gtk_menu_new ();
		      gtk_menu_item_set_submenu (GTK_MENU_ITEM (info->proxy), menu);
		      gtk_menu_set_accel_group (GTK_MENU (menu), self->private_data->accel_group);
		      gtk_menu_shell_insert (GTK_MENU_SHELL (menushell), info->proxy, pos);
		    }
		}
	      else
		{
		  gtk_action_connect_proxy (info->action, info->proxy);
		}
	      if (prev_submenu)
		{
		  gtk_menu_item_set_submenu (GTK_MENU_ITEM (info->proxy),
					     prev_submenu);
		  g_object_unref (prev_submenu);
		}
	    }
	  break;
	case GTK_MENU_MERGE_UNDECIDED:
	  g_warning ("found 'undecided node!");
	  break;
	case GTK_MENU_MERGE_ROOT:
	  break;
	case GTK_MENU_MERGE_TOOLBAR:
	  if (info->proxy == NULL)
	    {
	      info->proxy = gtk_toolbar_new ();
	      gtk_widget_show (info->proxy);
	      g_signal_emit (self, merge_signals[ADD_WIDGET], 0, info->proxy);
	    }
	  break;
	case GTK_MENU_MERGE_MENU_PLACEHOLDER:
	  /* create menu items for placeholders if necessary ... */
	  if (!GTK_IS_SEPARATOR_MENU_ITEM (info->proxy) ||
	      !GTK_IS_SEPARATOR_MENU_ITEM (info->extra))
	    {
	      if (info->proxy)
		gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
				      info->proxy);
	      if (info->extra)
		gtk_container_remove (GTK_CONTAINER (info->extra->parent),
				      info->extra);
	      info->proxy = NULL;
	      info->extra = NULL;
	    }
	  if (info->proxy == NULL)
	    {
	      GtkWidget *menushell;
	      gint pos;

	      if (find_menu_position (node, &menushell, &pos))
		{
		  NODE_INFO (node)->proxy = gtk_separator_menu_item_new ();
		  gtk_menu_shell_insert (GTK_MENU_SHELL (menushell),
					NODE_INFO (node)->proxy, pos);

		  NODE_INFO (node)->extra = gtk_separator_menu_item_new ();
		  gtk_menu_shell_insert (GTK_MENU_SHELL (menushell),
					 NODE_INFO (node)->extra, pos+1);
		}
	    }
	  break;
	case GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER:
	  /* create toolbar items for placeholders if necessary ... */
	  if (!GTK_IS_SEPARATOR_TOOL_ITEM (info->proxy) ||
	      !GTK_IS_SEPARATOR_TOOL_ITEM (info->extra))
	    {
	      if (info->proxy)
		gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
				      info->proxy);
	      if (info->extra)
		gtk_container_remove (GTK_CONTAINER (info->extra->parent),
				      info->extra);
	      info->proxy = NULL;
	      info->extra = NULL;
	    }
	  if (info->proxy == NULL)
	    {
	      GtkWidget *toolbar;
	      gint pos;

	      if (find_toolbar_position (node, &toolbar, &pos))
		{
		  GtkToolItem *item;

		  item = gtk_separator_tool_item_new ();
		  gtk_toolbar_insert (GTK_TOOLBAR (toolbar), item, pos);
		  NODE_INFO(node)->proxy = GTK_WIDGET (item);

		  item = gtk_separator_tool_item_new ();
		  gtk_toolbar_insert (GTK_TOOLBAR (toolbar), item, pos+1);
		  NODE_INFO (node)->extra = GTK_WIDGET (item);
		}
	    }
	  break;
	case GTK_MENU_MERGE_POPUPS:
	  break;
	case GTK_MENU_MERGE_MENUITEM:
	  /* remove the proxy if it is of the wrong type ... */
	  if (info->proxy &&  G_OBJECT_TYPE (info->proxy) !=
	      GTK_ACTION_GET_CLASS (info->action)->menu_item_type)
	    {
	      gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
				    info->proxy);
	      info->proxy = NULL;
	    }
	  /* create proxy if needed ... */
	  if (info->proxy == NULL)
	    {
	      GtkWidget *menushell;
	      gint pos;

	      if (find_menu_position (node, &menushell, &pos))
		{
		  info->proxy = gtk_action_create_menu_item (info->action);

		  gtk_menu_shell_insert (GTK_MENU_SHELL (menushell),
					 info->proxy, pos);
		}
	    }
	  else
	    {
	      gtk_menu_item_set_submenu (GTK_MENU_ITEM (info->proxy), NULL);
	      gtk_action_connect_proxy (info->action, info->proxy);
	    }
	  break;
	case GTK_MENU_MERGE_TOOLITEM:
	  /* remove the proxy if it is of the wrong type ... */
	  if (info->proxy &&  G_OBJECT_TYPE (info->proxy) !=
	      GTK_ACTION_GET_CLASS (info->action)->toolbar_item_type)
	    {
	      gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
				    info->proxy);
	      info->proxy = NULL;
	    }
	  /* create proxy if needed ... */
	  if (info->proxy == NULL)
	    {
	      GtkWidget *toolbar;
	      gint pos;

	      if (find_toolbar_position (node, &toolbar, &pos))
		{
		  info->proxy = gtk_action_create_tool_item (info->action);

		  gtk_toolbar_insert (GTK_TOOLBAR (toolbar),
					        GTK_TOOL_ITEM (info->proxy), pos);
		}
	    }
	  else
	    {
	      gtk_action_connect_proxy (info->action, info->proxy);
	    }
	  break;
	case GTK_MENU_MERGE_SEPARATOR:
	  if (NODE_INFO (node->parent)->type == GTK_MENU_MERGE_TOOLBAR ||
	      NODE_INFO (node->parent)->type == GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER)
	    {
	      GtkWidget *toolbar;
	      gint pos;

	      if (GTK_IS_SEPARATOR_TOOL_ITEM (info->proxy))
		{
		  gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
					info->proxy);
		  info->proxy = NULL;
		}

	      if (find_toolbar_position (node, &toolbar, &pos))
		{
		  GtkToolItem *item = gtk_separator_tool_item_new ();
		  gtk_toolbar_insert (GTK_TOOLBAR (toolbar), item, pos);
		  info->proxy = GTK_WIDGET (item);
		  gtk_widget_show (info->proxy);
		}
	    }
	  else
	    {
	      GtkWidget *menushell;
	      gint pos;

	      if (GTK_IS_SEPARATOR_MENU_ITEM (info->proxy))
		{
		  gtk_container_remove (GTK_CONTAINER (info->proxy->parent),
					info->proxy);
		  info->proxy = NULL;
		}

	      if (find_menu_position (node, &menushell, &pos))
		{
		  info->proxy = gtk_separator_menu_item_new ();
		  gtk_menu_shell_insert (GTK_MENU_SHELL (menushell),
					 info->proxy, pos);
		  gtk_widget_show (info->proxy);
		}
	    }
	  break;
	}

      /* if this node has a widget, but it is the wrong type, remove it */
    }

 recurse_children:
  /* process children */
  child = node->children;
  while (child)
    {
      GNode *current;

      current = child;
      child = current->next;
      update_node (self, current);
    }

  /* handle cleanup of dead nodes */
  if (node->children == NULL && NODE_INFO (node)->uifiles == NULL)
    {
      if (NODE_INFO (node)->proxy)
	gtk_widget_destroy (NODE_INFO (node)->proxy);
      if ((NODE_INFO (node)->type == GTK_MENU_MERGE_MENU_PLACEHOLDER ||
	   NODE_INFO (node)->type == GTK_MENU_MERGE_TOOLBAR_PLACEHOLDER) &&
	  NODE_INFO (node)->extra)
	gtk_widget_destroy (NODE_INFO (node)->extra);
      g_chunk_free (NODE_INFO (node), merge_node_chunk);
      g_node_destroy (node);
    }
}

static gboolean
do_updates (GtkMenuMerge *self)
{
  /* this function needs to check through the tree for dirty nodes.
   * For such nodes, it needs to do the following:
   *
   * 1) check if they are referenced by any loaded UI files anymore.
   *    In which case, the proxy widget should be destroyed, unless
   *    there are any subnodes.
   *
   * 2) lookup the action for this node again.  If it is different to
   *    the current one (or if no previous action has been looked up),
   *    the proxy is reconnected to the new action (or a new proxy widget
   *    is created and added to the parent container).
   */

  update_node (self, self->private_data->root_node);

  self->private_data->update_tag = 0;

  return FALSE;
}

static void
gtk_menu_merge_queue_update (GtkMenuMerge *self)
{
  if (self->private_data->update_tag != 0)
    return;

  self->private_data->update_tag = g_idle_add ((GSourceFunc)do_updates, self);
}

static void
gtk_menu_merge_ensure_update (GtkMenuMerge *self)
{
  if (self->private_data->update_tag != 0)
    {
      g_source_remove (self->private_data->update_tag);
      do_updates (self);
    }
}

static gboolean
dirty_traverse_func (GNode   *node, 
		     gpointer data)
{
  NODE_INFO (node)->dirty = TRUE;
  return FALSE;
}

static void
gtk_menu_merge_dirty_all (GtkMenuMerge *self)
{
  g_node_traverse (self->private_data->root_node, G_PRE_ORDER, G_TRAVERSE_ALL, -1,
		   dirty_traverse_func, NULL);
  gtk_menu_merge_queue_update (self);
}

static const gchar *open_tag_format[] = {
  "%*s<UNDECIDED>\n",
  "%*s<Root>\n",
  "%*s<menu name=\"%s\">\n",  
  "%*s<submenu name=\"%s\" verb=\"%s\">\n",
  "%*s<dockitem name=\"%s\">\n",
  "%*s<placeholder name=\"%s\">\n",
  "%*s<placeholder name=\"%s\">\n",
  "%*s<popups>\n",
  "%*s<menuitem name=\"%s\" verb=\"%s\"/>\n", 
  "%*s<toolitem name=\"%s\" verb=\"%s\"/>\n", 
  "%*s<separator/>\n",
  "%*s<popup name=\"%s\">\n"
};

static const gchar *close_tag_format[] = {
  "%*s</UNDECIDED>\n",
  "%*s</Root>\n",
  "%*s</menu>\n",
  "%*s</submenu>\n",
  "%*s</dockitem>\n",
  "%*s</placeholder>\n",
  "%*s</placeholder>\n",
  "%*s</popups>\n",
  "",
  "",
  "",
  "%*s</popup>\n"
};

static void
print_node (GtkMenuMerge *self, 
	    GNode        *node, 
	    gint          indent_level,
	    GString      *buffer)
{
  GtkMenuMergeNode *mnode;
  GNode *child;
  guint type;
  
  mnode = node->data;
  if (mnode->type == GTK_MENU_MERGE_MENU &&
      NODE_INFO (node->parent)->type == GTK_MENU_MERGE_POPUPS)
      type = GTK_MENU_MERGE_SEPARATOR + 1;
  else
    type = mnode->type;

  g_string_append_printf (buffer, open_tag_format[type],
			  indent_level, "",
			  mnode->name, 
			  g_quark_to_string (mnode->action_name));

  for (child = node->children; child != NULL; child = child->next) 
    print_node (self, child, indent_level + 2, buffer);

  g_string_append_printf (buffer, close_tag_format[type],
			  indent_level, "");

}

/**
 * gtk_menu_merge_get_ui:
 * @self: a #GtkMenuMerge
 * 
 * Creates an XML representation of the merged ui.
 * 
 * Return value: A newly allocated string containing an XML representation of 
 * the merged ui.
 **/
gchar*
gtk_menu_merge_get_ui (GtkMenuMerge   *self)
{
  GString *buffer;

  buffer = g_string_new (NULL);

  gtk_menu_merge_ensure_update (self); 
 
  print_node (self, self->private_data->root_node, 0, buffer);  

  return g_string_free (buffer, FALSE);
}