glib2.0/gio/gsocketaddressenumerator.c

201 lines
7.2 KiB
C

/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2008 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/>.
*/
#include "config.h"
#include "gsocketaddressenumerator.h"
#include "glibintl.h"
#include "gtask.h"
/**
* SECTION:gsocketaddressenumerator
* @short_description: Enumerator for socket addresses
* @include: gio/gio.h
*
* #GSocketAddressEnumerator is an enumerator type for #GSocketAddress
* instances. It is returned by enumeration functions such as
* g_socket_connectable_enumerate(), which returns a #GSocketAddressEnumerator
* to list each #GSocketAddress which could be used to connect to that
* #GSocketConnectable.
*
* Enumeration is typically a blocking operation, so the asynchronous methods
* g_socket_address_enumerator_next_async() and
* g_socket_address_enumerator_next_finish() should be used where possible.
*
* Each #GSocketAddressEnumerator can only be enumerated once. Once
* g_socket_address_enumerator_next() has returned %NULL, further
* enumeration with that #GSocketAddressEnumerator is not possible, and it can
* be unreffed.
*/
G_DEFINE_ABSTRACT_TYPE (GSocketAddressEnumerator, g_socket_address_enumerator, G_TYPE_OBJECT)
static void g_socket_address_enumerator_real_next_async (GSocketAddressEnumerator *enumerator,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
static GSocketAddress *g_socket_address_enumerator_real_next_finish (GSocketAddressEnumerator *enumerator,
GAsyncResult *result,
GError **error);
static void
g_socket_address_enumerator_init (GSocketAddressEnumerator *enumerator)
{
}
static void
g_socket_address_enumerator_class_init (GSocketAddressEnumeratorClass *enumerator_class)
{
enumerator_class->next_async = g_socket_address_enumerator_real_next_async;
enumerator_class->next_finish = g_socket_address_enumerator_real_next_finish;
}
/**
* g_socket_address_enumerator_next:
* @enumerator: a #GSocketAddressEnumerator
* @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
* @error: a #GError.
*
* Retrieves the next #GSocketAddress from @enumerator. Note that this
* may block for some amount of time. (Eg, a #GNetworkAddress may need
* to do a DNS lookup before it can return an address.) Use
* g_socket_address_enumerator_next_async() if you need to avoid
* blocking.
*
* If @enumerator is expected to yield addresses, but for some reason
* is unable to (eg, because of a DNS error), then the first call to
* g_socket_address_enumerator_next() will return an appropriate error
* in *@error. However, if the first call to
* g_socket_address_enumerator_next() succeeds, then any further
* internal errors (other than @cancellable being triggered) will be
* ignored.
*
* Returns: (transfer full) (nullable): a #GSocketAddress (owned by the caller), or %NULL on
* error (in which case *@error will be set) or if there are no
* more addresses.
*/
GSocketAddress *
g_socket_address_enumerator_next (GSocketAddressEnumerator *enumerator,
GCancellable *cancellable,
GError **error)
{
GSocketAddressEnumeratorClass *klass;
g_return_val_if_fail (G_IS_SOCKET_ADDRESS_ENUMERATOR (enumerator), NULL);
klass = G_SOCKET_ADDRESS_ENUMERATOR_GET_CLASS (enumerator);
return (* klass->next) (enumerator, cancellable, error);
}
/* Default implementation just calls the synchronous method; this can
* be used if the implementation already knows all of its addresses,
* and so the synchronous method will never block.
*/
static void
g_socket_address_enumerator_real_next_async (GSocketAddressEnumerator *enumerator,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
GSocketAddress *address;
GError *error = NULL;
task = g_task_new (enumerator, NULL, callback, user_data);
g_task_set_source_tag (task, g_socket_address_enumerator_real_next_async);
address = g_socket_address_enumerator_next (enumerator, cancellable, &error);
if (error)
g_task_return_error (task, error);
else
g_task_return_pointer (task, address, g_object_unref);
g_object_unref (task);
}
/**
* g_socket_address_enumerator_next_async:
* @enumerator: a #GSocketAddressEnumerator
* @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): a #GAsyncReadyCallback to call when the request
* is satisfied
* @user_data: (closure): the data to pass to callback function
*
* Asynchronously retrieves the next #GSocketAddress from @enumerator
* and then calls @callback, which must call
* g_socket_address_enumerator_next_finish() to get the result.
*
* It is an error to call this multiple times before the previous callback has finished.
*/
void
g_socket_address_enumerator_next_async (GSocketAddressEnumerator *enumerator,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSocketAddressEnumeratorClass *klass;
g_return_if_fail (G_IS_SOCKET_ADDRESS_ENUMERATOR (enumerator));
klass = G_SOCKET_ADDRESS_ENUMERATOR_GET_CLASS (enumerator);
(* klass->next_async) (enumerator, cancellable, callback, user_data);
}
static GSocketAddress *
g_socket_address_enumerator_real_next_finish (GSocketAddressEnumerator *enumerator,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, enumerator), NULL);
return g_task_propagate_pointer (G_TASK (result), error);
}
/**
* g_socket_address_enumerator_next_finish:
* @enumerator: a #GSocketAddressEnumerator
* @result: a #GAsyncResult
* @error: a #GError
*
* Retrieves the result of a completed call to
* g_socket_address_enumerator_next_async(). See
* g_socket_address_enumerator_next() for more information about
* error handling.
*
* Returns: (transfer full) (nullable): a #GSocketAddress (owned by the caller), or %NULL on
* error (in which case *@error will be set) or if there are no
* more addresses.
*/
GSocketAddress *
g_socket_address_enumerator_next_finish (GSocketAddressEnumerator *enumerator,
GAsyncResult *result,
GError **error)
{
GSocketAddressEnumeratorClass *klass;
g_return_val_if_fail (G_IS_SOCKET_ADDRESS_ENUMERATOR (enumerator), NULL);
klass = G_SOCKET_ADDRESS_ENUMERATOR_GET_CLASS (enumerator);
return (* klass->next_finish) (enumerator, result, error);
}