/* GIO - GLib Input, Output and Streaming Library

 *

 * Copyright (C) 2009 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 2.1 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 "ginitable.h"

#include "glibintl.h"

/**

 * SECTION:ginitable

 * @short_description: Failable object initialization interface

 * @include: gio/gio.h

 * @see_also: #GAsyncInitable

 *

 * #GInitable is implemented by objects that can fail during

 * initialization. If an object implements this interface then

 * it must be initialized as the first thing after construction,

 * either via g_initable_init() or g_async_initable_init_async()

 * (the latter is only available if it also implements #GAsyncInitable).

 *

 * If the object is not initialized, or initialization returns with an

 * error, then all operations on the object except g_object_ref() and

 * g_object_unref() are considered to be invalid, and have undefined

 * behaviour. They will often fail with g_critical() or g_warning(), but

 * this must not be relied on.

 *

 * Users of objects implementing this are not intended to use

 * the interface method directly, instead it will be used automatically

 * in various ways. For C applications you generally just call

 * g_initable_new() directly, or indirectly via a foo_thing_new() wrapper.

 * This will call g_initable_init() under the cover, returning %NULL and

 * setting a #GError on failure (at which point the instance is

 * unreferenced).

 *

 * For bindings in languages where the native constructor supports

 * exceptions the binding could check for objects implemention %GInitable

 * during normal construction and automatically initialize them, throwing

 * an exception on failure.

 */

typedef GInitableIface GInitableInterface;

G_DEFINE_INTERFACE (GInitable, g_initable, G_TYPE_OBJECT)

static void

g_initable_default_init (GInitableInterface *iface)

{

}

/**

 * g_initable_init:

 * @initable: a #GInitable.

 * @cancellable: optional #GCancellable object, %NULL to ignore.

 * @error: a #GError location to store the error occurring, or %NULL to

 * ignore.

 *

 * Initializes the object implementing the interface.

 *

 * This method is intended for language bindings. If writing in C,

 * g_initable_new() should typically be used instead.

 *

 * The object must be initialized before any real use after initial

 * construction, either with this function or g_async_initable_init_async().

 *

 * Implementations may also support cancellation. If @cancellable is not %NULL,

 * then initialization can be cancelled by triggering the cancellable object

 * from another thread. If the operation was cancelled, the error

 * %G_IO_ERROR_CANCELLED will be returned. If @cancellable is not %NULL and

 * the object doesn't support cancellable initialization the error

 * %G_IO_ERROR_NOT_SUPPORTED will be returned.

 *

 * If the object is not initialized, or initialization returns with an

 * error, then all operations on the object except g_object_ref() and

 * g_object_unref() are considered to be invalid, and have undefined

 * behaviour. See the [introduction][ginitable] for more details.

 *

 * Callers should not assume that a class which implements #GInitable can be

 * initialized multiple times, unless the class explicitly documents itself as

 * supporting this. Generally, a class’ implementation of init() can assume

 * (and assert) that it will only be called once. Previously, this documentation

 * recommended all #GInitable implementations should be idempotent; that

 * recommendation was relaxed in GLib 2.54.

 *

 * If a class explicitly supports being initialized multiple times, it is

 * recommended that the method is idempotent: multiple calls with the same

 * arguments should return the same results. Only the first call initializes

 * the object; further calls return the result of the first call.

 *

 * One reason why a class might need to support idempotent initialization is if

 * it is designed to be used via the singleton pattern, with a

 * #GObjectClass.constructor that sometimes returns an existing instance.

 * In this pattern, a caller would expect to be able to call g_initable_init()

 * on the result of g_object_new(), regardless of whether it is in fact a new

 * instance.

 *

 * Returns: %TRUE if successful. If an error has occurred, this function will

 *     return %FALSE and set @error appropriately if present.

 *

 * Since: 2.22

 */

gboolean

g_initable_init (GInitable     *initable,

		 GCancellable  *cancellable,

		 GError       **error)

{

  GInitableIface *iface;

  g_return_val_if_fail (G_IS_INITABLE (initable), FALSE);

  iface = G_INITABLE_GET_IFACE (initable);

  return (* iface->init) (initable, cancellable, error);

}

/**

 * g_initable_new:

 * @object_type: a #GType supporting #GInitable.

 * @cancellable: optional #GCancellable object, %NULL to ignore.

 * @error: a #GError location to store the error occurring, or %NULL to

 *    ignore.

 * @first_property_name: (nullable): the name of the first property, or %NULL if no

 *     properties

 * @...:  the value if the first property, followed by and other property

 *    value pairs, and ended by %NULL.

 *

 * Helper function for constructing #GInitable object. This is

 * similar to g_object_new() but also initializes the object

 * and returns %NULL, setting an error on failure.

 *

 * Returns: (type GObject.Object) (transfer full): a newly allocated

 *      #GObject, or %NULL on error

 *

 * Since: 2.22

 */

gpointer

g_initable_new (GType          object_type,

		GCancellable  *cancellable,

		GError       **error,

		const gchar   *first_property_name,

		...)

{

  GObject *object;

  va_list var_args;

  va_start (var_args, first_property_name);

  object = g_initable_new_valist (object_type,

				  first_property_name, var_args,

				  cancellable, error);

  va_end (var_args);

  return object;

}

/**

 * g_initable_newv:

 * @object_type: a #GType supporting #GInitable.

 * @n_parameters: the number of parameters in @parameters

 * @parameters: (array length=n_parameters): the parameters to use to construct the object

 * @cancellable: optional #GCancellable object, %NULL to ignore.

 * @error: a #GError location to store the error occurring, or %NULL to

 *     ignore.

 *

 * Helper function for constructing #GInitable object. This is

 * similar to g_object_newv() but also initializes the object

 * and returns %NULL, setting an error on failure.

 *

 * Returns: (type GObject.Object) (transfer full): a newly allocated

 *      #GObject, or %NULL on error

 *

 * Since: 2.22

 * Deprecated: 2.54: Use g_object_new_with_properties() and

 * g_initable_init() instead. See #GParameter for more information.

 */

gpointer

g_initable_newv (GType          object_type,

		 guint          n_parameters,

		 GParameter    *parameters,

		 GCancellable  *cancellable,

		 GError       **error)

{

  GObject *obj;

  g_return_val_if_fail (G_TYPE_IS_INITABLE (object_type), NULL);

G_GNUC_BEGIN_IGNORE_DEPRECATIONS

  obj = g_object_newv (object_type, n_parameters, parameters);

G_GNUC_END_IGNORE_DEPRECATIONS

  if (!g_initable_init (G_INITABLE (obj), cancellable, error))

    {

      g_object_unref (obj);

      return NULL;

    }

  return (gpointer)obj;

}

/**

 * g_initable_new_valist:

 * @object_type: a #GType supporting #GInitable.

 * @first_property_name: the name of the first property, followed by

 * the value, and other property value pairs, and ended by %NULL.

 * @var_args: The var args list generated from @first_property_name.

 * @cancellable: optional #GCancellable object, %NULL to ignore.

 * @error: a #GError location to store the error occurring, or %NULL to

 *     ignore.

 *

 * Helper function for constructing #GInitable object. This is

 * similar to g_object_new_valist() but also initializes the object

 * and returns %NULL, setting an error on failure.

 *

 * Returns: (type GObject.Object) (transfer full): a newly allocated

 *      #GObject, or %NULL on error

 *

 * Since: 2.22

 */

GObject*

g_initable_new_valist (GType          object_type,

		       const gchar   *first_property_name,

		       va_list        var_args,

		       GCancellable  *cancellable,

		       GError       **error)

{

  GObject *obj;

  g_return_val_if_fail (G_TYPE_IS_INITABLE (object_type), NULL);

  obj = g_object_new_valist (object_type,

			     first_property_name,

			     var_args);

  if (!g_initable_init (G_INITABLE (obj), cancellable, error))

    {

      g_object_unref (obj);

      return NULL;

    }

  return obj;

}