gio/gsocketconnectable.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2008 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include "config.h"
  22 #include "gsocketconnectable.h"
  23 #include "glibintl.h"
  24
  25 #include "gioalias.h"
  26
  27 /**
  28  * SECTION:gsocketconnectable
  29  * @short_description: Interface for potential socket endpoints
  30  *
  31  * Objects that describe one or more potential socket endpoints
  32  * implement #GSocketConnectable. Callers can then use
  33  * g_socket_connectable_enumerate() to get a #GSocketAddressEnumerator
  34  * to try out each socket address in turn until one succeeds, as shown
  35  * in the sample code below.
  36  *
  37  * |[
  38  * MyConnectionType *
  39  * connect_to_host (const char    *hostname,
  40  *                  guint16        port,
  41  *                  GCancellable  *cancellable,
  42  *                  GError       **error)
  43  * {
  44  *   MyConnection *conn = NULL;
  45  *   GSocketConnectable *addr;
  46  *   GSocketAddressEnumerator *enumerator;
  47  *   GSocketAddress *sockaddr;
  48  *   GError *conn_error = NULL;
  49  *
  50  *   addr = g_network_address_new ("www.gnome.org", 80);
  51  *   enumerator = g_socket_connectable_enumerate (addr);
  52  *   g_object_unref (addr);
  53  *
  54  *   /<!-- -->* Try each sockaddr until we succeed. Record the first
  55  *    * connection error, but not any further ones (since they'll probably
  56  *    * be basically the same as the first).
  57  *    *<!-- -->/
  58  *   while (!conn && (sockaddr = g_socket_address_enumerator_next (enumerator, cancellable, error))
  59  *     {
  60  *       conn = connect_to_sockaddr (sockaddr, conn_error ? NULL : &conn_error);
  61  *       g_object_unref (sockaddr);
  62  *     }
  63  *   g_object_unref (enumerator);
  64  *
  65  *   if (conn)
  66  *     {
  67  *       if (conn_error)
  68  *         {
  69  *           /<!-- -->* We couldn't connect to the first address, but we succeeded
  70  *            * in connecting to a later address.
  71  *            *<!-- -->/
  72  *           g_error_free (conn_error);
  73  *         }
  74  *       return conn;
  75  *     }
  76  *   else if (error)
  77  *     {
  78  *       /<!-- -->* Either the initial lookup failed, or else the caller
  79  *        * cancelled us.
  80  *        *<!-- -->/
  81  *       if (conn_error)
  82  *         g_error_free (conn_error);
  83  *       return NULL;
  84  *     }
  85  *   else
  86  *     {
  87  *       g_error_propagate (error, conn_error);
  88  *       return NULL;
  89  *     }
  90  * }
  91  * ]|
  92  */
  93
  94 GType
  95 g_socket_connectable_get_type (void)
  96 {
  97   static volatile gsize g_define_type_id__volatile = 0;
  98
  99   if (g_once_init_enter (&g_define_type_id__volatile))
 100     {
 101       const GTypeInfo connectable_info =
 102       {
 103         sizeof (GSocketConnectableIface), /* class_size */
 104         NULL,           /* base_init */
 105         NULL,           /* base_finalize */
 106         NULL,
 107         NULL,           /* class_finalize */
 108         NULL,           /* class_data */
 109         0,
 110         0,              /* n_preallocs */
 111         NULL
 112       };
 113       GType g_define_type_id =
 114         g_type_register_static (G_TYPE_INTERFACE, I_("GSocketConnectable"),
 115                                 &connectable_info, 0);
 116
 117       g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_OBJECT);
 118
 119       g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
 120     }
 121
 122   return g_define_type_id__volatile;
 123 }
 124
 125 /**
 126  * g_socket_connectable_enumerate:
 127  * @connectable: a #GSocketConnectable
 128  *
 129  * Creates a #GSocketAddressEnumerator for @connectable.
 130  *
 131  * Return value: a new #GSocketAddressEnumerator.
 132  *
 133  * Since: 2.22
 134  */
 135 GSocketAddressEnumerator *
 136 g_socket_connectable_enumerate (GSocketConnectable *connectable)
 137 {
 138   GSocketConnectableIface *iface;
 139
 140   g_return_val_if_fail (G_IS_SOCKET_CONNECTABLE (connectable), NULL);
 141
 142   iface = G_SOCKET_CONNECTABLE_GET_IFACE (connectable);
 143
 144   return (* iface->enumerate) (connectable);
 145 }
 146
 147 #define __G_SOCKET_CONNECTABLE_C__
 148 #include "gioaliasdef.c"