/* 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);
*
* 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.
*/
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));
G_GNUC_BEGIN_IGNORE_DEPRECATIONS
obj = g_object_newv (object_type, n_parameters, parameters);
G_GNUC_END_IGNORE_DEPRECATIONS
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_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;
}