gtk2/gtk/gtkfilesystem.c

/* GTK - The GIMP Toolkit
 * gtkfilesystem.c: Abstract file system interfaces
 * Copyright (C) 2003, Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <gmodule.h>
#include "gtkfilesystem.h"
#include "gtkicontheme.h"
#include "gtkmain.h"

#include <string.h>

struct _GtkFileInfo
{
  GtkFileTime modification_time;
  gint64 size;
  gchar *display_name;
  gchar *display_key;
  gchar *mime_type;
  guint is_folder : 1;
  guint is_hidden : 1;
};

static void gtk_file_system_base_init (gpointer g_class);
static void gtk_file_folder_base_init (gpointer g_class);

GQuark
gtk_file_system_error_quark (void)
{
  static GQuark quark = 0;
  if (quark == 0)
    quark = g_quark_from_static_string ("gtk-file-system-error-quark");
  return quark;
}

/*****************************************
 *             GtkFileInfo               *
 *****************************************/
GType
gtk_file_info_get_type (void)
{
  static GType our_type = 0;
  
  if (our_type == 0)
    our_type = g_boxed_type_register_static ("GtkFileInfo",
					     (GBoxedCopyFunc) gtk_file_info_copy,
					     (GBoxedFreeFunc) gtk_file_info_free);

  return our_type;
}

GtkFileInfo *
gtk_file_info_new  (void)
{
  GtkFileInfo *info;
  
  info = g_new0 (GtkFileInfo, 1);

  return info;
}

GtkFileInfo *
gtk_file_info_copy (GtkFileInfo *info)
{
  GtkFileInfo *new_info;

  g_return_val_if_fail (info != NULL, NULL);

  new_info = g_memdup (info, sizeof (GtkFileInfo));
  if (new_info->display_name)
    new_info->display_name = g_strdup (new_info->display_name);
  if (new_info->mime_type)
    new_info->mime_type = g_strdup (new_info->mime_type);

  return new_info;
}

void
gtk_file_info_free (GtkFileInfo *info)
{
  g_return_if_fail (info != NULL);

  if (info->display_name)
    g_free (info->display_name);
  if (info->mime_type)
    g_free (info->mime_type);
  if (info->display_key)
    g_free (info->display_key);

  g_free (info);
}

G_CONST_RETURN gchar *
gtk_file_info_get_display_name (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, NULL);
  
  return info->display_name;
}

/**
 * gtk_file_info_get_display_key:
 * @info: a #GtkFileInfo
 * 
 * Returns results of g_utf8_collate_key() on the display name
 * for @info. This is useful when sorting a bunch of #GtkFileInfo
 * structures since the collate key will be only computed once.
 * 
 * Return value: The collate key for the display name, or %NULL
 *   if the display name hasn't been set.
 **/
G_CONST_RETURN gchar *
gtk_file_info_get_display_key (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, NULL);

  if (!info->display_key && info->display_name)
    {
      /* Since info->display_key is only a cache, we cast off the const
       */
      ((GtkFileInfo *)info)->display_key = g_utf8_collate_key (info->display_name, -1);
    }
	
  return info->display_key;
}

void
gtk_file_info_set_display_name (GtkFileInfo *info,
				const gchar *display_name)
{
  g_return_if_fail (info != NULL);

  if (info->display_name)
    g_free (info->display_name);
  if (info->display_key)
    {
      g_free (info->display_key);
      info->display_key = NULL;
    }

  info->display_name = g_strdup (display_name);
}

gboolean
gtk_file_info_get_is_folder (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, FALSE);
  
  return info->is_folder;
}

void
gtk_file_info_set_is_folder (GtkFileInfo *info,
			     gboolean     is_folder)
{
  g_return_if_fail (info != NULL);

  info->is_folder = is_folder != FALSE;
}

gboolean
gtk_file_info_get_is_hidden (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, FALSE);
  
  return info->is_hidden;
}

void
gtk_file_info_set_is_hidden (GtkFileInfo *info,
			     gboolean     is_hidden)
{
  g_return_if_fail (info != NULL);

  info->is_hidden = is_hidden != FALSE;
}

G_CONST_RETURN gchar *
gtk_file_info_get_mime_type (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, NULL);
  
  return info->mime_type;
}

void
gtk_file_info_set_mime_type (GtkFileInfo *info,
			     const gchar *mime_type)
{
  g_return_if_fail (info != NULL);
  
  if (info->mime_type)
    g_free (info->mime_type);

  info->mime_type = g_strdup (mime_type);
}

GtkFileTime
gtk_file_info_get_modification_time (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, 0);

  return info->modification_time;
}

void
gtk_file_info_set_modification_time (GtkFileInfo *info,
				     GtkFileTime  modification_time)
{
  g_return_if_fail (info != NULL);
  
  info->modification_time = modification_time;
}

gint64
gtk_file_info_get_size (const GtkFileInfo *info)
{
  g_return_val_if_fail (info != NULL, 0);
  
  return info->size;
}

void
gtk_file_info_set_size (GtkFileInfo *info,
			gint64       size)
{
  g_return_if_fail (info != NULL);
  g_return_if_fail (size >= 0);
  
  info->size = size;
}


/*****************************************
 *             GtkFileSystem             *
 *****************************************/
GType
gtk_file_system_get_type (void)
{
  static GType file_system_type = 0;

  if (!file_system_type)
    {
      static const GTypeInfo file_system_info =
      {
	sizeof (GtkFileSystemIface),  /* class_size */
	gtk_file_system_base_init,    /* base_init */
	NULL,                         /* base_finalize */
      };

      file_system_type = g_type_register_static (G_TYPE_INTERFACE,
						 "GtkFileSystem",
						 &file_system_info, 0);

      g_type_interface_add_prerequisite (file_system_type, G_TYPE_OBJECT);
    }

  return file_system_type;
}

static void
gtk_file_system_base_init (gpointer g_class)
{
  static gboolean initialized = FALSE;
  
  if (!initialized)
    {
      GType iface_type = G_TYPE_FROM_INTERFACE (g_class);

      g_signal_new ("volumes-changed",
		    iface_type,
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkFileSystemIface, volumes_changed),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__VOID,
		    G_TYPE_NONE, 0);
      g_signal_new ("bookmarks-changed",
		    iface_type,
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkFileSystemIface, bookmarks_changed),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__VOID,
		    G_TYPE_NONE, 0);

      initialized = TRUE;
    }
}

GSList *
gtk_file_system_list_volumes (GtkFileSystem  *file_system)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->list_volumes (file_system);
}

GtkFileFolder *
gtk_file_system_get_folder (GtkFileSystem     *file_system,
			    const GtkFilePath *path,
			    GtkFileInfoType    types,
			    GError           **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (path != NULL, NULL);
  g_return_val_if_fail (error == NULL || *error == NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->get_folder (file_system, path, types, error);
}

gboolean
gtk_file_system_create_folder(GtkFileSystem     *file_system,
			      const GtkFilePath *path,
			      GError           **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (path != NULL, FALSE);
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->create_folder (file_system, path, error);
}

/**
 * gtk_file_system_get_volume_for_path:
 * @file_system: a #GtkFileSystem
 * @path: a #GtkFilePath
 * 
 * Queries the file system volume that corresponds to a specific path.
 * There might not be a volume for all paths (consinder for instance remote
 * shared), so this can return NULL.
 * 
 * Return value: the #GtkFileSystemVolume that corresponds to the specified
 * @path, or NULL if there is no such volume. You should free this value with
 * gtk_file_system_volume_free().
 **/
GtkFileSystemVolume *
gtk_file_system_get_volume_for_path (GtkFileSystem     *file_system,
				     const GtkFilePath *path)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (path != NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->get_volume_for_path (file_system, path);
}

/**
 * gtk_file_system_volume_free:
 * @file_system: a #GtkFileSystem
 * @volume: a #GtkFileSystemVolume
 * 
 * Frees a #GtkFileSystemVolume structure as returned by
 * gtk_file_system_list_volumes().
 **/
void
gtk_file_system_volume_free (GtkFileSystem       *file_system,
			     GtkFileSystemVolume *volume)
{
  g_return_if_fail (GTK_IS_FILE_SYSTEM (file_system));
  g_return_if_fail (volume != NULL);

  GTK_FILE_SYSTEM_GET_IFACE (file_system)->volume_free (file_system, volume);
}

/**
 * gtk_file_system_volume_get_base_path:
 * @file_system: a #GtkFileSystem
 * @volume: a #GtkFileSystemVolume
 * 
 * Queries the base path for a volume.  For example, a CD-ROM device may yield a
 * path of "/mnt/cdrom".
 * 
 * Return value: a #GtkFilePath with the base mount path of the specified
 * @volume.
 **/
GtkFilePath *
gtk_file_system_volume_get_base_path (GtkFileSystem       *file_system,
				      GtkFileSystemVolume *volume)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (volume != NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->volume_get_base_path (file_system, volume);
}

/**
 * gtk_file_system_volume_get_is_mounted:
 * @file_system: a #GtkFileSystem
 * @volume: a #GtkFileSystemVolume
 * 
 * Queries whether a #GtkFileSystemVolume is mounted or not.  If it is not, it
 * can be mounted with gtk_file_system_volume_mount().
 * 
 * Return value: TRUE if the @volume is mounted, FALSE otherwise.
 **/
gboolean
gtk_file_system_volume_get_is_mounted (GtkFileSystem       *file_system,
				       GtkFileSystemVolume *volume)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (volume != NULL, FALSE);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->volume_get_is_mounted (file_system, volume);
}

/**
 * gtk_file_system_volume_mount:
 * @file_system: a #GtkFileSystem
 * @volume: a #GtkFileSystemVolume
 * @error: location to store error, or %NULL
 * 
 * Tries to mount an unmounted volume.  This may cause the "volumes-changed"
 * signal in the @file_system to be emitted.
 * 
 * Return value: TRUE if the @volume was mounted successfully, FALSE otherwise.
 **/
gboolean
gtk_file_system_volume_mount (GtkFileSystem        *file_system, 
			      GtkFileSystemVolume  *volume,
			      GError              **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (volume != NULL, FALSE);
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->volume_mount (file_system, volume, error);
}

/**
 * gtk_file_system_volume_get_display_name:
 * @file_system: a #GtkFileSystem
 * @volume: a #GtkFileSystemVolume
 * 
 * Queries the human-readable name for a @volume.  This string can be displayed
 * in a list of volumes that can be accessed, for example.
 * 
 * Return value: A string with the human-readable name for a #GtkFileSystemVolume.
 **/
char *
gtk_file_system_volume_get_display_name (GtkFileSystem        *file_system, 
					 GtkFileSystemVolume  *volume)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (volume != NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->volume_get_display_name (file_system, volume);
}

/**
 * gtk_file_system_volume_render_icon:
 * @file_system: a #GtkFileSystem
 * @volume: a #GtkFileSystemVolume
 * @widget: Reference widget to render icons.
 * @pixel_size: Size of the icon.
 * @error: location to store error, or %NULL
 * 
 * Renders an icon suitable for a file #GtkFileSystemVolume.
 * 
 * Return value: A #GdkPixbuf containing an icon, or NULL if the icon could not
 * be rendered.  In the latter case, the @error value will be set as
 * appropriate.
 **/
GdkPixbuf *
gtk_file_system_volume_render_icon (GtkFileSystem        *file_system,
				    GtkFileSystemVolume  *volume,
				    GtkWidget            *widget,
				    gint                  pixel_size,
				    GError              **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (volume != NULL, NULL);
  g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
  g_return_val_if_fail (pixel_size > 0, NULL);
  g_return_val_if_fail (error == NULL || *error == NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->volume_render_icon (file_system,
								      volume,
								      widget,
								      pixel_size,
								      error);
}

/**
 * gtk_file_system_get_parent:
 * @file_system: a #GtkFileSystem
 * @path: base path name
 * @parent: location to store parent path name
 * @error: location to store error, or %NULL
 * 
 * Gets the name of the parent folder of a path.  If the path has no parent, as when
 * you request the parent of a file system root, then @parent will be set to %NULL.
 * 
 * Return value: %TRUE if the operation was successful:  @parent will be set to
 * the name of the @path's parent, or to %NULL if @path is already a file system
 * root.  If the operation fails, this function returns %FALSE, sets @parent to
 * NULL, and sets the @error value if it is specified.
 **/
gboolean
gtk_file_system_get_parent (GtkFileSystem     *file_system,
			    const GtkFilePath *path,
			    GtkFilePath      **parent,
			    GError           **error)
{
  gboolean result;
  
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (path != NULL, FALSE);
  g_return_val_if_fail (parent != NULL, FALSE);
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  *parent = NULL;

  result = GTK_FILE_SYSTEM_GET_IFACE (file_system)->get_parent (file_system, path, parent, error);
  g_assert (result || *parent == NULL);

  return result;
}

GtkFilePath *
gtk_file_system_make_path (GtkFileSystem    *file_system,
			  const GtkFilePath *base_path,
			  const gchar       *display_name,
			  GError           **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (base_path != NULL, NULL);
  g_return_val_if_fail (display_name != NULL, NULL);
  g_return_val_if_fail (error == NULL || *error == NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->make_path (file_system, base_path, display_name, error);
}

/**
 * gtk_file_system_parse:
 * @file_system: a #GtkFileSystem
 * @base_path: reference folder with respect to which relative
 *            paths should be interpreted.
 * @str: the string to parse
 * @folder: location to store folder portion of result, or %NULL
 * @file_part: location to store file portion of result, or %NULL
 * @error: location to store error, or %NULL
 * 
 * Given a string entered by a user, parse it (possibly using
 * heuristics) into a folder path and a UTF-8 encoded
 * filename part. (Suitable for passing to gtk_file_system_make_path())
 *
 * Note that the returned filename point may point to a subfolder
 * of the returned folder. Adding a trailing path separator is needed
 * to enforce the interpretation as a folder name.
 *
 * If parsing fails because the syntax of @str is not understood,
 * and error of type GTK_FILE_SYSTEM_ERROR_BAD_FILENAME will
 * be set in @error and %FALSE returned.
 *
 * If parsing fails because a path was encountered that doesn't
 * exist on the filesystem, then an error of type
 * %GTK_FILE_SYSTEM_ERROR_NONEXISTENT will be set in @error
 * and %FALSE returned. (This only applies to parsing relative paths,
 * not to interpretation of @file_part. No check is made as
 * to whether @file_part exists.)
 *
 * Return value: %TRUE if the parsing succeeds, otherwise, %FALSE.
 **/
gboolean
gtk_file_system_parse (GtkFileSystem     *file_system,
		       const GtkFilePath *base_path,
		       const gchar       *str,
		       GtkFilePath      **folder,
		       gchar            **file_part,
		       GError           **error)
{
  GtkFilePath *tmp_folder = NULL;
  gchar *tmp_file_part = NULL;
  gboolean result;

  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (base_path != NULL, FALSE);
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);


  result = GTK_FILE_SYSTEM_GET_IFACE (file_system)->parse (file_system, base_path, str,
							   &tmp_folder, &tmp_file_part,
							   error);
  g_assert (result || (tmp_folder == NULL && tmp_file_part == NULL));

  if (folder)
    *folder = tmp_folder;
  else
    gtk_file_path_free (tmp_folder);

  if (file_part)
    *file_part = tmp_file_part;
  else
    g_free (tmp_file_part);

  return result;
}


gchar *
gtk_file_system_path_to_uri (GtkFileSystem     *file_system,
			     const GtkFilePath *path)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (path != NULL, NULL);
  
  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->path_to_uri (file_system, path);
}

gchar *
gtk_file_system_path_to_filename (GtkFileSystem     *file_system,
				  const GtkFilePath *path)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (path != NULL, NULL);
  
  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->path_to_filename (file_system, path);
}

GtkFilePath *
gtk_file_system_uri_to_path (GtkFileSystem *file_system,
			     const gchar    *uri)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (uri != NULL, NULL);
  
  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->uri_to_path (file_system, uri);
}

GtkFilePath *
gtk_file_system_filename_to_path (GtkFileSystem *file_system,
				  const gchar   *filename)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (filename != NULL, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->filename_to_path (file_system, filename);
}

GdkPixbuf *
gtk_file_system_render_icon (GtkFileSystem      *file_system,
			     const GtkFilePath  *path,
			     GtkWidget          *widget,
			     gint                pixel_size,
			     GError            **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);
  g_return_val_if_fail (path != NULL, NULL);
  g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
  g_return_val_if_fail (pixel_size > 0, NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->render_icon (file_system, path, widget, pixel_size, error);
}

/**
 * gtk_file_system_insert_bookmark:
 * @file_system: a #GtkFileSystem
 * @path: path of the bookmark to add
 * @position: index in the bookmarks list at which the @path should be inserted; use 0
 * for the beginning, and -1 or the number of bookmarks itself for the end of the list.
 * @error: location to store error, or %NULL
 * 
 * Adds a path for a folder to the user's bookmarks list.  If the operation
 * succeeds, the "bookmarks_changed" signal will be emitted.  Bookmark paths are
 * unique; if you try to insert a @path that already exists, the operation will
 * fail and the @error will be set to #GTK_FILE_SYSTEM_ERROR_ALREADY_EXISTS.  To
 * reorder the list of bookmarks, use gtk_file_system_remove_bookmark() to
 * remove the path in question, and call gtk_file_system_insert_bookmark() with
 * the new position for the path.
 * 
 * Return value: TRUE if the operation succeeds, FALSE otherwise.  In the latter case,
 * the @error value will be set.
 **/
gboolean
gtk_file_system_insert_bookmark (GtkFileSystem     *file_system,
				 const GtkFilePath *path,
				 gint               position,
				 GError           **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (path != NULL, FALSE);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->insert_bookmark (file_system, path, position, error);
}

/**
 * gtk_file_system_remove_bookmark:
 * @file_system: a #GtkFileSystem
 * @path: path of the bookmark to remove
 * @error: location to store error, or %NULL
 * 
 * Removes a bookmark folder from the user's bookmarks list.  If the operation
 * succeeds, the "bookmarks_changed" signal will be emitted.  If you try to remove
 * a @path which does not exist in the bookmarks list, the operation will fail
 * and the @error will be set to GTK_FILE_SYSTEM_ERROR_NONEXISTENT.
 * 
 * Return value: TRUE if the operation succeeds, FALSE otherwise.  In the latter
 * case, the @error value will be set.
 **/
gboolean
gtk_file_system_remove_bookmark (GtkFileSystem     *file_system,
				 const GtkFilePath *path,
				 GError           **error)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), FALSE);
  g_return_val_if_fail (path != NULL, FALSE);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->remove_bookmark (file_system, path, error);
}

/**
 * gtk_file_system_list_bookmarks:
 * @file_system: a #GtkFileSystem
 * 
 * Queries the list of bookmarks in the file system.
 * 
 * Return value: A list of #GtkFilePath, or NULL if there are no configured
 * bookmarks.  You should use gtk_file_paths_free() to free this list.
 *
 * See also: gtk_file_system_get_supports_bookmarks()
 **/
GSList *
gtk_file_system_list_bookmarks (GtkFileSystem *file_system)
{
  g_return_val_if_fail (GTK_IS_FILE_SYSTEM (file_system), NULL);

  return GTK_FILE_SYSTEM_GET_IFACE (file_system)->list_bookmarks (file_system);
}

/*****************************************
 *             GtkFileFolder             *
 *****************************************/
GType
gtk_file_folder_get_type (void)
{
  static GType file_folder_type = 0;

  if (!file_folder_type)
    {
      static const GTypeInfo file_folder_info =
      {
	sizeof (GtkFileFolderIface),  /* class_size */
	gtk_file_folder_base_init,    /* base_init */
	NULL,                         /* base_finalize */
      };

      file_folder_type = g_type_register_static (G_TYPE_INTERFACE,
						 "GtkFileFolder",
						 &file_folder_info, 0);
      
      g_type_interface_add_prerequisite (file_folder_type, G_TYPE_OBJECT);
    }

  return file_folder_type;
}

static void
gtk_file_folder_base_init (gpointer g_class)
{
  static gboolean initialized = FALSE;
  
  if (!initialized)
    {
      GType iface_type = G_TYPE_FROM_INTERFACE (g_class);

      g_signal_new ("deleted",
		    iface_type,
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkFileFolderIface, deleted),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__VOID,
		    G_TYPE_NONE, 0);
      g_signal_new ("files-added",
		    iface_type,
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkFileFolderIface, files_added),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__POINTER,
		    G_TYPE_NONE, 1,
		    G_TYPE_POINTER);
      g_signal_new ("files-changed",
		    iface_type,
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkFileFolderIface, files_changed),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__POINTER,
		    G_TYPE_NONE, 1,
		    G_TYPE_POINTER);
      g_signal_new ("files-removed",
		    iface_type,
		    G_SIGNAL_RUN_LAST,
		    G_STRUCT_OFFSET (GtkFileFolderIface, files_removed),
		    NULL, NULL,
		    g_cclosure_marshal_VOID__POINTER,
		    G_TYPE_NONE, 1,
		    G_TYPE_POINTER);

      initialized = TRUE;
    }
}

gboolean
gtk_file_folder_list_children (GtkFileFolder    *folder,
			       GSList          **children,
			       GError          **error)
{
  gboolean result;
  GSList *tmp_children = NULL;
  
  g_return_val_if_fail (GTK_IS_FILE_FOLDER (folder), FALSE);
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  result = GTK_FILE_FOLDER_GET_IFACE (folder)->list_children (folder, &tmp_children, error);
  g_assert (result || tmp_children == NULL);

  if (children)
    *children = tmp_children;
  else
    gtk_file_paths_free (tmp_children);

  return result;
}

GtkFileInfo *
gtk_file_folder_get_info (GtkFileFolder     *folder,
			  const GtkFilePath *path,
			  GError           **error)
{
  g_return_val_if_fail (GTK_IS_FILE_FOLDER (folder), NULL);
  g_return_val_if_fail (path != NULL, NULL);
  g_return_val_if_fail (error == NULL || *error == NULL, NULL);

  return GTK_FILE_FOLDER_GET_IFACE (folder)->get_info (folder, path, error);
}

GSList *
gtk_file_paths_sort (GSList *paths)
{
  return g_slist_sort (paths, (GCompareFunc)strcmp);
}

/**
 * gtk_file_paths_copy:
 * @paths: A #GSList of #GtkFilePath structures.
 * 
 * Copies a list of #GtkFilePath structures.
 * 
 * Return value: A copy of @paths.  Since the contents of the list are copied as
 * well, you should use gtk_file_paths_free() to free the result.
 **/
GSList *
gtk_file_paths_copy (GSList *paths)
{
  GSList *head, *tail, *l;

  head = tail = NULL;

  for (l = paths; l; l = l->next)
    {
      GtkFilePath *path;
      GSList *node;

      path = l->data;
      node = g_slist_alloc ();

      if (tail)
	tail->next = node;
      else
	head = node;

      node->data = gtk_file_path_copy (path);
      tail = node;
    }

  return head;
}

void
gtk_file_paths_free (GSList *paths)
{
  GSList *tmp_list;

  for (tmp_list = paths; tmp_list; tmp_list = tmp_list->next)
    gtk_file_path_free (tmp_list->data);

  g_slist_free (paths);
}

/*****************************************
 *         GtkFileSystem modules         *
 *****************************************/

typedef struct _GtkFileSystemModule GtkFileSystemModule;
typedef struct _GtkFileSystemModuleClass GtkFileSystemModuleClass;

struct _GtkFileSystemModule
{
  GTypeModule parent_instance;
  
  GModule *library;

  void            (*init)     (GTypeModule    *module);
  void            (*exit)     (void);
  GtkFileSystem * (*create)   (void);

  gchar *path;
};

struct _GtkFileSystemModuleClass
{
  GTypeModuleClass parent_class;
};

G_DEFINE_TYPE (GtkFileSystemModule, gtk_file_system_module, G_TYPE_TYPE_MODULE);
#define GTK_TYPE_FILE_SYSTEM_MODULE       (gtk_file_system_module_get_type ())
#define GTK_FILE_SYSTEM_MODULE(module)	  (G_TYPE_CHECK_INSTANCE_CAST ((module), GTK_TYPE_FILE_SYSTEM_MODULE, GtkFileSystemModule))


static GSList *loaded_file_systems;

static gboolean
gtk_file_system_module_load (GTypeModule *module)
{
  GtkFileSystemModule *fs_module = GTK_FILE_SYSTEM_MODULE (module);
  
  fs_module->library = g_module_open (fs_module->path, 0);
  if (!fs_module->library)
    {
      g_warning (g_module_error());
      return FALSE;
    }
  
  /* extract symbols from the lib */
  if (!g_module_symbol (fs_module->library, "fs_module_init",
			(gpointer *)&fs_module->init) ||
      !g_module_symbol (fs_module->library, "fs_module_exit", 
			(gpointer *)&fs_module->exit) ||
      !g_module_symbol (fs_module->library, "fs_module_create", 
			(gpointer *)&fs_module->create))
    {
      g_warning (g_module_error());
      g_module_close (fs_module->library);
      
      return FALSE;
    }
	    
  /* call the filesystems's init function to let it */
  /* setup anything it needs to set up. */
  fs_module->init (module);

  return TRUE;
}

static void
gtk_file_system_module_unload (GTypeModule *module)
{
  GtkFileSystemModule *fs_module = GTK_FILE_SYSTEM_MODULE (module);
  
  fs_module->exit();

  g_module_close (fs_module->library);
  fs_module->library = NULL;

  fs_module->init = NULL;
  fs_module->exit = NULL;
  fs_module->create = NULL;
}

/* This only will ever be called if an error occurs during
 * initialization
 */
static void
gtk_file_system_module_finalize (GObject *object)
{
  GtkFileSystemModule *module = GTK_FILE_SYSTEM_MODULE (object);

  g_free (module->path);

  G_OBJECT_CLASS (gtk_file_system_module_parent_class)->finalize (object);
}

static void
gtk_file_system_module_class_init (GtkFileSystemModuleClass *class)
{
  GTypeModuleClass *module_class = G_TYPE_MODULE_CLASS (class);
  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
  
  module_class->load = gtk_file_system_module_load;
  module_class->unload = gtk_file_system_module_unload;

  gobject_class->finalize = gtk_file_system_module_finalize;
}

static void
gtk_file_system_module_init (GtkFileSystemModule *fs_module)
{
}


static GtkFileSystem *
_gtk_file_system_module_create (GtkFileSystemModule *fs_module)
{
  GtkFileSystem *fs;
  
  if (g_type_module_use (G_TYPE_MODULE (fs_module)))
    {
      fs = fs_module->create ();
      g_type_module_unuse (G_TYPE_MODULE (fs_module));
      return fs;
    }
  return NULL;
}


GtkFileSystem *
_gtk_file_system_create (const char *file_system_name)
{
  GSList *l;
  char *module_path;
  GtkFileSystemModule *fs_module;
  GtkFileSystem *fs;

  for (l = loaded_file_systems; l != NULL; l = l->next)
    {
      fs_module = l->data;
      
      if (strcmp (G_TYPE_MODULE (fs_module)->name, file_system_name) == 0)
	return _gtk_file_system_module_create (fs_module);
    }

  fs = NULL;
  if (g_module_supported ())
    {
      module_path = _gtk_find_module (file_system_name, "filesystems");

      if (module_path)
	{
	  fs_module = g_object_new (GTK_TYPE_FILE_SYSTEM_MODULE, NULL);

	  g_type_module_set_name (G_TYPE_MODULE (fs_module), file_system_name);
	  fs_module->path = g_strdup (module_path);

	  loaded_file_systems = g_slist_prepend (loaded_file_systems,
						 fs_module);

	  fs = _gtk_file_system_module_create (fs_module);
	}
      
      g_free (module_path);
    }
  
  return fs;
}