/* 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;
}