/* GIO - GLib Input, Output and Streaming Library

 *

 * Copyright (C) 2006-2007 Red Hat, Inc.

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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: Alexander Larsson <alexl@redhat.com>

 */

#include "config.h"

#include <string.h>

#include "gvfs.h"

#include "glib-private.h"

#include "glocalvfs.h"

#include "gresourcefile.h"

#include "giomodule-priv.h"

#include "glibintl.h"

/**

 * SECTION:gvfs

 * @short_description: Virtual File System

 * @include: gio/gio.h

 *

 * Entry point for using GIO functionality.

 *

 */

static GRWLock additional_schemes_lock;

typedef struct _GVfsPrivate {

  GHashTable *additional_schemes;

  char const **supported_schemes;

} GVfsPrivate;

typedef struct {

  GVfsFileLookupFunc uri_func;

  gpointer uri_data;

  GDestroyNotify uri_destroy;

  GVfsFileLookupFunc parse_name_func;

  gpointer parse_name_data;

  GDestroyNotify parse_name_destroy;

} GVfsURISchemeData;

G_DEFINE_TYPE_WITH_PRIVATE (GVfs, g_vfs, G_TYPE_OBJECT)

static void

g_vfs_dispose (GObject *object)

{

  GVfs *vfs = G_VFS (object);

  GVfsPrivate *priv = g_vfs_get_instance_private (vfs);

  g_clear_pointer (&priv->additional_schemes, g_hash_table_destroy);

  g_clear_pointer (&priv->supported_schemes, g_free);

  G_OBJECT_CLASS (g_vfs_parent_class)->dispose (object);

}

static void

g_vfs_class_init (GVfsClass *klass)

{

  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->dispose = g_vfs_dispose;

}

static GFile *

resource_parse_name (GVfs       *vfs,

                     const char *parse_name,

                     gpointer    user_data)

{

  if (g_str_has_prefix (parse_name, "resource:"))

    return _g_resource_file_new (parse_name);

  return NULL;

}

static GFile *

resource_get_file_for_uri (GVfs       *vfs,

                           const char *uri,

                           gpointer    user_data)

{

  return _g_resource_file_new (uri);

}

static void

g_vfs_uri_lookup_func_closure_free (gpointer data)

{

  GVfsURISchemeData *closure = data;

  if (closure->uri_destroy)

    closure->uri_destroy (closure->uri_data);

  if (closure->parse_name_destroy)

    closure->parse_name_destroy (closure->parse_name_data);

  g_free (closure);

}

static void

g_vfs_init (GVfs *vfs)

{

  GVfsPrivate *priv = g_vfs_get_instance_private (vfs);

  priv->additional_schemes =

    g_hash_table_new_full (g_str_hash, g_str_equal,

                           g_free, g_vfs_uri_lookup_func_closure_free);

  g_vfs_register_uri_scheme (vfs, "resource",

                             resource_get_file_for_uri, NULL, NULL,

                             resource_parse_name, NULL, NULL);

}

/**

 * g_vfs_is_active:

 * @vfs: a #GVfs.

 *

 * Checks if the VFS is active.

 *

 * Returns: %TRUE if construction of the @vfs was successful

 *     and it is now active.

 */

gboolean

g_vfs_is_active (GVfs *vfs)

{

  GVfsClass *class;

  g_return_val_if_fail (G_IS_VFS (vfs), FALSE);

  class = G_VFS_GET_CLASS (vfs);

  return (* class->is_active) (vfs);

}

/**

 * g_vfs_get_file_for_path:

 * @vfs: a #GVfs.

 * @path: a string containing a VFS path.

 *

 * Gets a #GFile for @path.

 *

 * Returns: (transfer full): a #GFile.

 *     Free the returned object with g_object_unref().

 */

GFile *

g_vfs_get_file_for_path (GVfs       *vfs,

                         const char *path)

{

  GVfsClass *class;

  g_return_val_if_fail (G_IS_VFS (vfs), NULL);

  g_return_val_if_fail (path != NULL, NULL);

  class = G_VFS_GET_CLASS (vfs);

  return (* class->get_file_for_path) (vfs, path);

}

static GFile *

parse_name_internal (GVfs       *vfs,

                     const char *parse_name)

{

  GVfsPrivate *priv = g_vfs_get_instance_private (vfs);

  GHashTableIter iter;

  GVfsURISchemeData *closure;

  GFile *ret = NULL;

  g_rw_lock_reader_lock (&additional_schemes_lock);

  g_hash_table_iter_init (&iter, priv->additional_schemes);

  while (g_hash_table_iter_next (&iter, NULL, (gpointer *) &closure))

    {

      ret = closure->parse_name_func (vfs, parse_name,

                                      closure->parse_name_data);

      if (ret)

        break;

    }

  g_rw_lock_reader_unlock (&additional_schemes_lock);

  return ret;

}

static GFile *

get_file_for_uri_internal (GVfs       *vfs,

                           const char *uri)

{

  GVfsPrivate *priv = g_vfs_get_instance_private (vfs);

  GFile *ret = NULL;

  char *scheme;

  GVfsURISchemeData *closure;

  scheme = g_uri_parse_scheme (uri);

  if (scheme == NULL)

    return NULL;

  g_rw_lock_reader_lock (&additional_schemes_lock);

  closure = g_hash_table_lookup (priv->additional_schemes, scheme);

  if (closure)

    ret = closure->uri_func (vfs, uri, closure->uri_data);

  g_rw_lock_reader_unlock (&additional_schemes_lock);

  g_free (scheme);

  return ret;

}

/**

 * g_vfs_get_file_for_uri:

 * @vfs: a#GVfs.

 * @uri: a string containing a URI

 *

 * Gets a #GFile for @uri.

 *

 * This operation never fails, but the returned object

 * might not support any I/O operation if the URI

 * is malformed or if the URI scheme is not supported.

 *

 * Returns: (transfer full): a #GFile.

 *     Free the returned object with g_object_unref().

 */

GFile *

g_vfs_get_file_for_uri (GVfs       *vfs,

                        const char *uri)

{

  GVfsClass *class;

  GFile *ret = NULL;

  g_return_val_if_fail (G_IS_VFS (vfs), NULL);

  g_return_val_if_fail (uri != NULL, NULL);

  class = G_VFS_GET_CLASS (vfs);

  ret = get_file_for_uri_internal (vfs, uri);

  if (!ret)

    ret = (* class->get_file_for_uri) (vfs, uri);

  g_assert (ret != NULL);

  return g_steal_pointer (&ret);

}

/**

 * g_vfs_get_supported_uri_schemes:

 * @vfs: a #GVfs.

 *

 * Gets a list of URI schemes supported by @vfs.

 *

 * Returns: (transfer none): a %NULL-terminated array of strings.

 *     The returned array belongs to GIO and must

 *     not be freed or modified.

 */

const gchar * const *

g_vfs_get_supported_uri_schemes (GVfs *vfs)

{

  GVfsPrivate *priv;

  g_return_val_if_fail (G_IS_VFS (vfs), NULL);

  priv = g_vfs_get_instance_private (vfs);

  if (!priv->supported_schemes)

    {

      GVfsClass *class;

      const char * const *default_schemes;

      const char *additional_scheme;

      GPtrArray *supported_schemes;

      GHashTableIter iter;

      class = G_VFS_GET_CLASS (vfs);

      default_schemes = (* class->get_supported_uri_schemes) (vfs);

      supported_schemes = g_ptr_array_new ();

      for (; default_schemes && *default_schemes; default_schemes++)

        g_ptr_array_add (supported_schemes, (gpointer) *default_schemes);

      g_rw_lock_reader_lock (&additional_schemes_lock);

      g_hash_table_iter_init (&iter, priv->additional_schemes);

      while (g_hash_table_iter_next

             (&iter, (gpointer *) &additional_scheme, NULL))

        g_ptr_array_add (supported_schemes, (gpointer) additional_scheme);

      g_rw_lock_reader_unlock (&additional_schemes_lock);

      g_ptr_array_add (supported_schemes, NULL);

      g_free (priv->supported_schemes);

      priv->supported_schemes =

        (char const **) g_ptr_array_free (supported_schemes, FALSE);

    }

  return priv->supported_schemes;

}

/**

 * g_vfs_parse_name:

 * @vfs: a #GVfs.

 * @parse_name: a string to be parsed by the VFS module.

 *

 * This operation never fails, but the returned object might

 * not support any I/O operations if the @parse_name cannot

 * be parsed by the #GVfs module.

 *

 * Returns: (transfer full): a #GFile for the given @parse_name.

 *     Free the returned object with g_object_unref().

 */

GFile *

g_vfs_parse_name (GVfs       *vfs,

                  const char *parse_name)

{

  GVfsClass *class;

  GFile *ret;

  g_return_val_if_fail (G_IS_VFS (vfs), NULL);

  g_return_val_if_fail (parse_name != NULL, NULL);

  class = G_VFS_GET_CLASS (vfs);

  ret = parse_name_internal (vfs, parse_name);

  if (ret)

    return ret;

  return (* class->parse_name) (vfs, parse_name);

}

static GVfs *vfs_default_singleton = NULL;  /* (owned) (atomic) */

/**

 * g_vfs_get_default:

 *

 * Gets the default #GVfs for the system.

 *

 * Returns: (not nullable) (transfer none): a #GVfs, which will be the local

 *     file system #GVfs if no other implementation is available.

 */

GVfs *

g_vfs_get_default (void)

{

  if (GLIB_PRIVATE_CALL (g_check_setuid) ())

    return g_vfs_get_local ();

  if (g_once_init_enter (&vfs_default_singleton))

    {

      GVfs *singleton;

      singleton = _g_io_module_get_default (G_VFS_EXTENSION_POINT_NAME,

                                            "GIO_USE_VFS",

                                            (GIOModuleVerifyFunc) g_vfs_is_active);

      g_once_init_leave (&vfs_default_singleton, singleton);

    }

  return vfs_default_singleton;

}

/**

 * g_vfs_get_local:

 *

 * Gets the local #GVfs for the system.

 *

 * Returns: (transfer none): a #GVfs.

 */

GVfs *

g_vfs_get_local (void)

{

  static gsize vfs = 0;

  if (g_once_init_enter (&vfs))

    g_once_init_leave (&vfs, (gsize)_g_local_vfs_new ());

  return G_VFS (vfs);

}

/**

 * g_vfs_register_uri_scheme:

 * @vfs: a #GVfs

 * @scheme: an URI scheme, e.g. "http"

 * @uri_func: (scope notified) (nullable): a #GVfsFileLookupFunc

 * @uri_data: (nullable): custom data passed to be passed to @uri_func, or %NULL

 * @uri_destroy: (nullable): function to be called when unregistering the

 *     URI scheme, or when @vfs is disposed, to free the resources used

 *     by the URI lookup function

 * @parse_name_func: (scope notified) (nullable): a #GVfsFileLookupFunc

 * @parse_name_data: (nullable): custom data passed to be passed to

 *     @parse_name_func, or %NULL

 * @parse_name_destroy: (nullable): function to be called when unregistering the

 *     URI scheme, or when @vfs is disposed, to free the resources used

 *     by the parse name lookup function

 *

 * Registers @uri_func and @parse_name_func as the #GFile URI and parse name

 * lookup functions for URIs with a scheme matching @scheme.

 * Note that @scheme is registered only within the running application, as

 * opposed to desktop-wide as it happens with GVfs backends.

 *

 * When a #GFile is requested with an URI containing @scheme (e.g. through

 * g_file_new_for_uri()), @uri_func will be called to allow a custom

 * constructor. The implementation of @uri_func should not be blocking, and

 * must not call g_vfs_register_uri_scheme() or g_vfs_unregister_uri_scheme().

 *

 * When g_file_parse_name() is called with a parse name obtained from such file,

 * @parse_name_func will be called to allow the #GFile to be created again. In

 * that case, it's responsibility of @parse_name_func to make sure the parse

 * name matches what the custom #GFile implementation returned when

 * g_file_get_parse_name() was previously called. The implementation of

 * @parse_name_func should not be blocking, and must not call

 * g_vfs_register_uri_scheme() or g_vfs_unregister_uri_scheme().

 *

 * It's an error to call this function twice with the same scheme. To unregister

 * a custom URI scheme, use g_vfs_unregister_uri_scheme().

 *

 * Returns: %TRUE if @scheme was successfully registered, or %FALSE if a handler

 *     for @scheme already exists.

 *

 * Since: 2.50

 */

gboolean

g_vfs_register_uri_scheme (GVfs              *vfs,

                           const char        *scheme,

                           GVfsFileLookupFunc uri_func,

                           gpointer           uri_data,

                           GDestroyNotify     uri_destroy,

                           GVfsFileLookupFunc parse_name_func,

                           gpointer           parse_name_data,

                           GDestroyNotify     parse_name_destroy)

{

  GVfsPrivate *priv;

  GVfsURISchemeData *closure;

  g_return_val_if_fail (G_IS_VFS (vfs), FALSE);

  g_return_val_if_fail (scheme != NULL, FALSE);

  priv = g_vfs_get_instance_private (vfs);

  g_rw_lock_reader_lock (&additional_schemes_lock);

  closure = g_hash_table_lookup (priv->additional_schemes, scheme);

  g_rw_lock_reader_unlock (&additional_schemes_lock);

  if (closure != NULL)

    return FALSE;

  closure = g_new0 (GVfsURISchemeData, 1);

  closure->uri_func = uri_func;

  closure->uri_data = uri_data;

  closure->uri_destroy = uri_destroy;

  closure->parse_name_func = parse_name_func;

  closure->parse_name_data = parse_name_data;

  closure->parse_name_destroy = parse_name_destroy;

  g_rw_lock_writer_lock (&additional_schemes_lock);

  g_hash_table_insert (priv->additional_schemes, g_strdup (scheme), closure);

  g_rw_lock_writer_unlock (&additional_schemes_lock);

  /* Invalidate supported schemes */

  g_clear_pointer (&priv->supported_schemes, g_free);

  return TRUE;

}

/**

 * g_vfs_unregister_uri_scheme:

 * @vfs: a #GVfs

 * @scheme: an URI scheme, e.g. "http"

 *

 * Unregisters the URI handler for @scheme previously registered with

 * g_vfs_register_uri_scheme().

 *

 * Returns: %TRUE if @scheme was successfully unregistered, or %FALSE if a

 *     handler for @scheme does not exist.

 *

 * Since: 2.50

 */

gboolean

g_vfs_unregister_uri_scheme (GVfs       *vfs,

                             const char *scheme)

{

  GVfsPrivate *priv;

  gboolean res;

  g_return_val_if_fail (G_IS_VFS (vfs), FALSE);

  g_return_val_if_fail (scheme != NULL, FALSE);

  priv = g_vfs_get_instance_private (vfs);

  g_rw_lock_writer_lock (&additional_schemes_lock);

  res = g_hash_table_remove (priv->additional_schemes, scheme);

  g_rw_lock_writer_unlock (&additional_schemes_lock);

  if (res)

    {

      /* Invalidate supported schemes */

      g_clear_pointer (&priv->supported_schemes, g_free);

      return TRUE;

    }

  return FALSE;

}