/* 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 "gasyncinitable.h"

#include "gasyncresult.h"

#include "gsimpleasyncresult.h"

#include "gtask.h"

#include "glibintl.h"

/**

 * SECTION:gasyncinitable

 * @short_description: Asynchronously failable object initialization interface

 * @include: gio/gio.h

 * @see_also: #GInitable

 *

 * This is the asynchronous version of #GInitable; it behaves the same

 * in all ways except that initialization is asynchronous. For more details

 * see the descriptions on #GInitable.

 *

 * A class may implement both the #GInitable and #GAsyncInitable interfaces.

 *

 * 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_async_initable_new_async()

 * directly, or indirectly via a foo_thing_new_async() wrapper. This will call

 * g_async_initable_init_async() under the cover, calling back with %NULL and

 * a set %GError on failure.

 *

 * A typical implementation might look something like this:

 *

 * |[<!-- language="C" -->

 * enum {

 *    NOT_INITIALIZED,

 *    INITIALIZING,

 *    INITIALIZED

 * };

 *

 * static void

 * _foo_ready_cb (Foo *self)

 * {

 *   GList *l;

 *

 *   self->priv->state = INITIALIZED;

 *

 *   for (l = self->priv->init_results; l != NULL; l = l->next)

 *     {

 *       GTask *task = l->data;

 *

 *       if (self->priv->success)

 *         g_task_return_boolean (task, TRUE);

 *       else

 *         g_task_return_new_error (task, ...);

 *       g_object_unref (task);

 *     }

 *

 *   g_list_free (self->priv->init_results);

 *   self->priv->init_results = NULL;

 * }

 *

 * static void

 * foo_init_async (GAsyncInitable       *initable,

 *                 int                   io_priority,

 *                 GCancellable         *cancellable,

 *                 GAsyncReadyCallback   callback,

 *                 gpointer              user_data)

 * {

 *   Foo *self = FOO (initable);

 *   GTask *task;

 *

 *   task = g_task_new (initable, cancellable, callback, user_data);

 *   g_task_set_name (task, G_STRFUNC);

 *

 *   switch (self->priv->state)

 *     {

 *       case NOT_INITIALIZED:

 *         _foo_get_ready (self);

 *         self->priv->init_results = g_list_append (self->priv->init_results,

 *                                                   task);

 *         self->priv->state = INITIALIZING;

 *         break;

 *       case INITIALIZING:

 *         self->priv->init_results = g_list_append (self->priv->init_results,

 *                                                   task);

 *         break;

 *       case INITIALIZED:

 *         if (!self->priv->success)

 *           g_task_return_new_error (task, ...);

 *         else

 *           g_task_return_boolean (task, TRUE);

 *         g_object_unref (task);

 *         break;

 *     }

 * }

 *

 * static gboolean

 * foo_init_finish (GAsyncInitable       *initable,

 *                  GAsyncResult         *result,

 *                  GError              **error)

 * {

 *   g_return_val_if_fail (g_task_is_valid (result, initable), FALSE);

 *

 *   return g_task_propagate_boolean (G_TASK (result), error);

 * }

 *

 * static void

 * foo_async_initable_iface_init (gpointer g_iface,

 *                                gpointer data)

 * {

 *   GAsyncInitableIface *iface = g_iface;

 *

 *   iface->init_async = foo_init_async;

 *   iface->init_finish = foo_init_finish;

 * }

 * ]|

 */

static void     g_async_initable_real_init_async  (GAsyncInitable       *initable,

               int                   io_priority,

               GCancellable         *cancellable,

               GAsyncReadyCallback   callback,

               gpointer              user_data);

static gboolean g_async_initable_real_init_finish (GAsyncInitable       *initable,

               GAsyncResult         *res,

               GError              **error);

typedef GAsyncInitableIface GAsyncInitableInterface;

G_DEFINE_INTERFACE (GAsyncInitable, g_async_initable, G_TYPE_OBJECT)

static void

g_async_initable_default_init (GAsyncInitableInterface *iface)

{

  iface->init_async = g_async_initable_real_init_async;

  iface->init_finish = g_async_initable_real_init_finish;

}

/**

 * g_async_initable_init_async:

 * @initable: a #GAsyncInitable.

 * @io_priority: the [I/O priority][io-priority] of the operation

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

 * @callback: a #GAsyncReadyCallback to call when the request is satisfied

 * @user_data: the data to pass to callback function

 *

 * Starts asynchronous initialization of the object implementing the

 * interface. This must be done before any real use of the object after

 * initial construction. If the object also implements #GInitable you can

 * optionally call g_initable_init() instead.

 *

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

 * g_async_initable_new_async() should typically be used instead.

 *

 * When the initialization is finished, @callback will be called. You can

 * then call g_async_initable_init_finish() to get the result of the

 * initialization.

 *

 * 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.

 *

 * As with #GInitable, 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.

 *

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

 * be initialized multiple times; for more information, see g_initable_init().

 * If a class explicitly supports being initialized multiple times,

 * implementation requires yielding all subsequent calls to init_async() on the

 * results of the first call.

 *

 * For classes that also support the #GInitable interface, the default

 * implementation of this method will run the g_initable_init() function

 * in a thread, so if you want to support asynchronous initialization via

 * threads, just implement the #GAsyncInitable interface without overriding

 * any interface methods.

 *

 * Since: 2.22

 */

void

g_async_initable_init_async (GAsyncInitable      *initable,

           int                  io_priority,

           GCancellable        *cancellable,

           GAsyncReadyCallback  callback,

           gpointer             user_data)

{

  GAsyncInitableIface *iface;

  g_return_if_fail (G_IS_ASYNC_INITABLE (initable));

  iface = G_ASYNC_INITABLE_GET_IFACE (initable);

  (* iface->init_async) (initable, io_priority, cancellable, callback, user_data);

}

/**

 * g_async_initable_init_finish:

 * @initable: a #GAsyncInitable.

 * @res: a #GAsyncResult.

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

 * ignore.

 *

 * Finishes asynchronous initialization and returns the result.

 * See g_async_initable_init_async().

 *

 * 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_async_initable_init_finish (GAsyncInitable  *initable,

            GAsyncResult    *res,

            GError         **error)

{

  GAsyncInitableIface *iface;

  g_return_val_if_fail (G_IS_ASYNC_INITABLE (initable), FALSE);

  g_return_val_if_fail (G_IS_ASYNC_RESULT (res), FALSE);

  if (g_async_result_legacy_propagate_error (res, error))

    return FALSE;

  iface = G_ASYNC_INITABLE_GET_IFACE (initable);

  return (* iface->init_finish) (initable, res, error);

}

static void

async_init_thread (GTask        *task,

                   gpointer      source_object,

                   gpointer      task_data,

                   GCancellable *cancellable)

{

  GError *error = NULL;

  if (g_initable_init (G_INITABLE (source_object), cancellable, &error))

    g_task_return_boolean (task, TRUE);

  else

    g_task_return_error (task, error);

}

static void

g_async_initable_real_init_async (GAsyncInitable      *initable,

          int                  io_priority,

          GCancellable        *cancellable,

          GAsyncReadyCallback  callback,

          gpointer             user_data)

{

  GTask *task;

  g_return_if_fail (G_IS_INITABLE (initable));

  task = g_task_new (initable, cancellable, callback, user_data);

  g_task_set_source_tag (task, g_async_initable_real_init_async);

  g_task_set_priority (task, io_priority);

  g_task_run_in_thread (task, async_init_thread);

  g_object_unref (task);

}

static gboolean

g_async_initable_real_init_finish (GAsyncInitable  *initable,

           GAsyncResult    *res,

           GError         **error)

{

  /* For backward compatibility we have to process GSimpleAsyncResults

   * even though g_async_initable_real_init_async doesn't generate

   * them any more.

   */

  G_GNUC_BEGIN_IGNORE_DEPRECATIONS

  if (G_IS_SIMPLE_ASYNC_RESULT (res))

    {

      GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res);

      if (g_simple_async_result_propagate_error (simple, error))

        return FALSE;

      else

        return TRUE;

    }

  G_GNUC_END_IGNORE_DEPRECATIONS

  g_return_val_if_fail (g_task_is_valid (res, initable), FALSE);

  return g_task_propagate_boolean (G_TASK (res), error);

}

/**

 * g_async_initable_new_async:

 * @object_type: a #GType supporting #GAsyncInitable.

 * @io_priority: the [I/O priority][io-priority] of the operation

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

 * @callback: a #GAsyncReadyCallback to call when the initialization is

 *     finished

 * @user_data: the data to pass to callback function

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

 *     properties

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

 *    value pairs, and ended by %NULL.

 *

 * Helper function for constructing #GAsyncInitable object. This is

 * similar to g_object_new() but also initializes the object asynchronously.

 *

 * When the initialization is finished, @callback will be called. You can

 * then call g_async_initable_new_finish() to get the new object and check

 * for any errors.

 *

 * Since: 2.22

 */

void

g_async_initable_new_async (GType                object_type,

          int                  io_priority,

          GCancellable        *cancellable,

          GAsyncReadyCallback  callback,

          gpointer             user_data,

          const gchar         *first_property_name,

          ...)

{

  va_list var_args;

  va_start (var_args, first_property_name);

  g_async_initable_new_valist_async (object_type,

             first_property_name, var_args,

             io_priority, cancellable,

             callback, user_data);

  va_end (var_args);

}

/**

 * g_async_initable_newv_async:

 * @object_type: a #GType supporting #GAsyncInitable.

 * @n_parameters: the number of parameters in @parameters

 * @parameters: the parameters to use to construct the object

 * @io_priority: the [I/O priority][io-priority] of the operation

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

 * @callback: a #GAsyncReadyCallback to call when the initialization is

 *     finished

 * @user_data: the data to pass to callback function

 *

 * Helper function for constructing #GAsyncInitable object. This is

 * similar to g_object_newv() but also initializes the object asynchronously.

 *

 * When the initialization is finished, @callback will be called. You can

 * then call g_async_initable_new_finish() to get the new object and check

 * for any errors.

 *

 * Since: 2.22

 * Deprecated: 2.54: Use g_object_new_with_properties() and

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

 */

G_GNUC_BEGIN_IGNORE_DEPRECATIONS

void

g_async_initable_newv_async (GType                object_type,

           guint                n_parameters,

           GParameter          *parameters,

           int                  io_priority,

           GCancellable        *cancellable,

           GAsyncReadyCallback  callback,

           gpointer             user_data)

{

  GObject *obj;

  g_return_if_fail (G_TYPE_IS_ASYNC_INITABLE (object_type));

  obj = g_object_newv (object_type, n_parameters, parameters);

  g_async_initable_init_async (G_ASYNC_INITABLE (obj),

             io_priority, cancellable,

             callback, user_data);

  g_object_unref (obj); /* Passed ownership to async call */

}

G_GNUC_END_IGNORE_DEPRECATIONS

/**

 * g_async_initable_new_valist_async:

 * @object_type: a #GType supporting #GAsyncInitable.

 * @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.

 * @io_priority: the [I/O priority][io-priority] of the operation

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

 * @callback: a #GAsyncReadyCallback to call when the initialization is

 *     finished

 * @user_data: the data to pass to callback function

 *

 * Helper function for constructing #GAsyncInitable object. This is

 * similar to g_object_new_valist() but also initializes the object

 * asynchronously.

 *

 * When the initialization is finished, @callback will be called. You can

 * then call g_async_initable_new_finish() to get the new object and check

 * for any errors.

 *

 * Since: 2.22

 */

void

g_async_initable_new_valist_async (GType                object_type,

           const gchar         *first_property_name,

           va_list              var_args,

           int                  io_priority,

           GCancellable        *cancellable,

           GAsyncReadyCallback  callback,

           gpointer             user_data)

{

  GObject *obj;

  g_return_if_fail (G_TYPE_IS_ASYNC_INITABLE (object_type));

  obj = g_object_new_valist (object_type,

           first_property_name,

           var_args);

  g_async_initable_init_async (G_ASYNC_INITABLE (obj),

             io_priority, cancellable,

             callback, user_data);

  g_object_unref (obj); /* Passed ownership to async call */

}

/**

 * g_async_initable_new_finish:

 * @initable: the #GAsyncInitable from the callback

 * @res: the #GAsyncResult from the callback

 * @error: return location for errors, or %NULL to ignore

 *

 * Finishes the async construction for the various g_async_initable_new

 * calls, returning the created object or %NULL on error.

 *

 * Returns: (type GObject.Object) (transfer full): a newly created #GObject,

 *      or %NULL on error. Free with g_object_unref().

 *

 * Since: 2.22

 */

GObject *

g_async_initable_new_finish (GAsyncInitable  *initable,

           GAsyncResult    *res,

           GError         **error)

{

  if (g_async_initable_init_finish (initable, res, error))

    return g_object_ref (G_OBJECT (initable));

  else

    return NULL;

}