/*

 * Copyright © 2010 Codethink Limited

 *

 * 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 2.1 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, see <http://www.gnu.org/licenses/>.

 *

 * Author: Ryan Lortie <desrt@desrt.ca>

 */

#include "config.h"

#include "gsettingsbackendinternal.h"

#include "giomodule.h"

#include "gsimplepermission.h"

#define G_TYPE_NULL_SETTINGS_BACKEND    (g_null_settings_backend_get_type ())

#define G_NULL_SETTINGS_BACKEND(inst)   (G_TYPE_CHECK_INSTANCE_CAST ((inst), \

                                         G_TYPE_NULL_SETTINGS_BACKEND,       \

                                         GNullSettingsBackend))

typedef GSettingsBackendClass GNullSettingsBackendClass;

typedef GSettingsBackend      GNullSettingsBackend;

G_DEFINE_TYPE_WITH_CODE (GNullSettingsBackend,

                         g_null_settings_backend,

                         G_TYPE_SETTINGS_BACKEND,

                         g_io_extension_point_implement (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME,

                                                         g_define_type_id, "null", 10))

static GVariant *

g_null_settings_backend_read (GSettingsBackend   *backend,

                              const gchar        *key,

                              const GVariantType *expected_type,

                              gboolean            default_value)

{

  return NULL;

}

static gboolean

g_null_settings_backend_write (GSettingsBackend *backend,

                               const gchar      *key,

                               GVariant         *value,

                               gpointer          origin_tag)

{

  if (value)

    g_variant_unref (g_variant_ref_sink (value));

  return FALSE;

}

static gboolean

g_null_settings_backend_write_one (gpointer key,

                                   gpointer value,

                                   gpointer data)

{

  if (value)

    g_variant_unref (g_variant_ref_sink (value));

  return FALSE;

}

static gboolean

g_null_settings_backend_write_tree (GSettingsBackend *backend,

                                    GTree            *tree,

                                    gpointer          origin_tag)

{

  g_tree_foreach (tree, g_null_settings_backend_write_one, backend);

  return FALSE;

}

static void

g_null_settings_backend_reset (GSettingsBackend *backend,

                               const gchar      *key,

                               gpointer          origin_tag)

{

}

static gboolean

g_null_settings_backend_get_writable (GSettingsBackend *backend,

                                      const gchar      *name)

{

  return FALSE;

}

static GPermission *

g_null_settings_backend_get_permission (GSettingsBackend *backend,

                                        const gchar      *path)

{

  return g_simple_permission_new (FALSE);

}

static void

g_null_settings_backend_init (GNullSettingsBackend *memory)

{

}

static void

g_null_settings_backend_class_init (GNullSettingsBackendClass *class)

{

  GSettingsBackendClass *backend_class = G_SETTINGS_BACKEND_CLASS (class);

  backend_class->read = g_null_settings_backend_read;

  backend_class->write = g_null_settings_backend_write;

  backend_class->write_tree = g_null_settings_backend_write_tree;

  backend_class->reset = g_null_settings_backend_reset;

  backend_class->get_writable = g_null_settings_backend_get_writable;

  backend_class->get_permission = g_null_settings_backend_get_permission;

}

/**

 * g_null_settings_backend_new:

 *

 *

 * Creates a readonly #GSettingsBackend.

 *

 * This backend does not allow changes to settings, so all settings

 * will always have their default values.

 *

 * Returns: (transfer full): a newly created #GSettingsBackend

 *

 * Since: 2.28

 */

GSettingsBackend *

g_null_settings_backend_new (void)

{

  return g_object_new (G_TYPE_NULL_SETTINGS_BACKEND, NULL);

}