glib/gio/gtcpconnection.c

/* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright © 2008, 2009 Codethink Limited
 *
 * This program 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 of the licence or (at
 * your option) any later version.
 *
 * See the included COPYING file for more information.
 */

/**
 * SECTION:gtcpconnection
 * @title: GTcpConnection
 * @short_description: A TCP GSocketConnection
 * @see_also: #GSocketConnection.
 *
 * This is the subclass of #GSocketConnection that is created
 * for TCP/IP sockets.
 *
 * Since: 2.22
 */

#include "config.h"
#include "gtcpconnection.h"
#include "gasyncresult.h"
#include "gsimpleasyncresult.h"
#include "giostream.h"
#include "glibintl.h"


G_DEFINE_TYPE_WITH_CODE (GTcpConnection, g_tcp_connection,
			 G_TYPE_SOCKET_CONNECTION,
  g_socket_connection_factory_register_type (g_define_type_id,
					     G_SOCKET_FAMILY_IPV4,
					     G_SOCKET_TYPE_STREAM,
					     G_SOCKET_PROTOCOL_DEFAULT);
  g_socket_connection_factory_register_type (g_define_type_id,
					     G_SOCKET_FAMILY_IPV6,
					     G_SOCKET_TYPE_STREAM,
					     G_SOCKET_PROTOCOL_DEFAULT);
  g_socket_connection_factory_register_type (g_define_type_id,
					     G_SOCKET_FAMILY_IPV4,
					     G_SOCKET_TYPE_STREAM,
					     G_SOCKET_PROTOCOL_TCP);
  g_socket_connection_factory_register_type (g_define_type_id,
					     G_SOCKET_FAMILY_IPV6,
					     G_SOCKET_TYPE_STREAM,
					     G_SOCKET_PROTOCOL_TCP);
			 );

static gboolean g_tcp_connection_close       (GIOStream            *stream,
					      GCancellable         *cancellable,
					      GError              **error);
static void     g_tcp_connection_close_async (GIOStream            *stream,
					      int                   io_priority,
					      GCancellable         *cancellable,
					      GAsyncReadyCallback   callback,
					      gpointer              user_data);

struct _GTcpConnectionPrivate
{
  guint graceful_disconnect : 1;
};


enum
{
  PROP_0,
  PROP_GRACEFUL_DISCONNECT
};

static void
g_tcp_connection_init (GTcpConnection *connection)
{
  connection->priv = G_TYPE_INSTANCE_GET_PRIVATE (connection,
                                                  G_TYPE_TCP_CONNECTION,
                                                  GTcpConnectionPrivate);
  connection->priv->graceful_disconnect = FALSE;
}

static void
g_tcp_connection_get_property (GObject    *object,
			       guint       prop_id,
			       GValue     *value,
			       GParamSpec *pspec)
{
  GTcpConnection *connection = G_TCP_CONNECTION (object);

  switch (prop_id)
    {
      case PROP_GRACEFUL_DISCONNECT:
	g_value_set_boolean (value, connection->priv->graceful_disconnect);
	break;

      default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
    }
}

static void
g_tcp_connection_set_property (GObject      *object,
			       guint         prop_id,
			       const GValue *value,
			       GParamSpec   *pspec)
{
  GTcpConnection *connection = G_TCP_CONNECTION (object);

  switch (prop_id)
    {
      case PROP_GRACEFUL_DISCONNECT:
	g_tcp_connection_set_graceful_disconnect (connection,
						  g_value_get_boolean (value));
	break;

      default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
    }
}

static void
g_tcp_connection_class_init (GTcpConnectionClass *class)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
  GIOStreamClass *stream_class = G_IO_STREAM_CLASS (class);

  g_type_class_add_private (class, sizeof (GTcpConnectionPrivate));

  gobject_class->set_property = g_tcp_connection_set_property;
  gobject_class->get_property = g_tcp_connection_get_property;

  stream_class->close_fn = g_tcp_connection_close;
  stream_class->close_async = g_tcp_connection_close_async;

  g_object_class_install_property (gobject_class, PROP_GRACEFUL_DISCONNECT,
				   g_param_spec_boolean ("graceful-disconnect",
							 P_("Graceful Disconnect"),
							 P_("Whether or not close does a graceful disconnect"),
							 FALSE,
							 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

}

static gboolean
g_tcp_connection_close (GIOStream     *stream,
			GCancellable  *cancellable,
			GError       **error)
{
  GTcpConnection *connection = G_TCP_CONNECTION (stream);
  GSocket *socket;
  char buffer[1024];
  gssize ret;
  GError *my_error;
  gboolean had_error;

  socket = g_socket_connection_get_socket (G_SOCKET_CONNECTION (stream));
  had_error = FALSE;

  if (connection->priv->graceful_disconnect &&
      !g_cancellable_is_cancelled (cancellable) /* Cancelled -> close fast */)
    {
      if (!g_socket_shutdown (socket, FALSE, TRUE, error))
	{
	  error = NULL; /* Ignore further errors */
	  had_error = TRUE;
	}
      else
	{
	  while (TRUE)
	    {
	      my_error = NULL;
	      ret = g_socket_receive (socket,  buffer, sizeof (buffer),
				      cancellable, &my_error);
	      if (ret < 0)
		{
		  if (g_error_matches (my_error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
		    g_error_free (my_error);
		  else
		    {
		      had_error = TRUE;
		      g_propagate_error (error, my_error);
		      error = NULL;
		      break;
		    }
		}
	      if (ret == 0)
		break;
	    }
	}
    }

  return G_IO_STREAM_CLASS (g_tcp_connection_parent_class)
    ->close_fn (stream, cancellable, error) && !had_error;
}

typedef struct {
  GSimpleAsyncResult *res;
  GCancellable *cancellable;
} CloseAsyncData;

static void
close_async_data_free (CloseAsyncData *data)
{
  g_object_unref (data->res);
  if (data->cancellable)
    g_object_unref (data->cancellable);
  g_free (data);
}

static void
async_close_finish (CloseAsyncData *data,
                    GError         *error /* consumed */,
                    gboolean        in_mainloop)
{
  GIOStreamClass *parent = G_IO_STREAM_CLASS (g_tcp_connection_parent_class);
  GIOStream *stream;
  GError *my_error;

  stream = G_IO_STREAM (g_async_result_get_source_object (G_ASYNC_RESULT (data->res)));

  /* Doesn't block, ignore error */
  if (error)
    {
      parent->close_fn (stream, data->cancellable, NULL);
      g_simple_async_result_take_error (data->res, error);
    }
  else
    {
      my_error = NULL;
      parent->close_fn (stream, data->cancellable, &my_error);
      if (my_error)
        g_simple_async_result_take_error (data->res, my_error);
    }

  if (in_mainloop)
    g_simple_async_result_complete (data->res);
  else
    g_simple_async_result_complete_in_idle (data->res);
}

static gboolean
close_read_ready (GSocket        *socket,
		  GIOCondition    condition,
		  CloseAsyncData *data)
{
  GError *error = NULL;
  char buffer[1024];
  gssize ret;

  ret = g_socket_receive (socket,  buffer, sizeof (buffer),
			  data->cancellable, &error);
  if (ret < 0)
    {
      if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
	g_error_free (error);
      else
	{
	  async_close_finish (data, error, TRUE);
	  return FALSE;
	}
    }

  if (ret == 0)
    {
      async_close_finish (data, NULL, TRUE);
      return FALSE;
    }

  return TRUE;
}


static void
g_tcp_connection_close_async (GIOStream           *stream,
			      int                  io_priority,
			      GCancellable        *cancellable,
			      GAsyncReadyCallback  callback,
			      gpointer             user_data)
{
  GTcpConnection *connection = G_TCP_CONNECTION (stream);
  CloseAsyncData *data;
  GSocket *socket;
  GSource *source;
  GError *error;

  if (connection->priv->graceful_disconnect &&
      !g_cancellable_is_cancelled (cancellable) /* Cancelled -> close fast */)
    {
      data = g_new (CloseAsyncData, 1);
      data->res =
	g_simple_async_result_new (G_OBJECT (stream), callback, user_data,
				   g_tcp_connection_close_async);
      if (cancellable)
	data->cancellable = g_object_ref (cancellable);
      else
	data->cancellable = NULL;

      socket = g_socket_connection_get_socket (G_SOCKET_CONNECTION (stream));

      error = NULL;
      if (!g_socket_shutdown (socket, FALSE, TRUE, &error))
	{
	  async_close_finish (data, error, FALSE);
	  close_async_data_free (data);
	  return;
	}

      source = g_socket_create_source (socket, G_IO_IN, cancellable);
      g_source_set_callback (source,
			     (GSourceFunc) close_read_ready,
			     data, (GDestroyNotify)close_async_data_free);
      g_source_attach (source, g_main_context_get_thread_default ());
      g_source_unref (source);

      return;
    }

  G_IO_STREAM_CLASS (g_tcp_connection_parent_class)
    ->close_async (stream, io_priority, cancellable, callback, user_data);
}

/**
 * g_tcp_connection_set_graceful_disconnect:
 * @connection: a #GTcpConnection
 * @graceful_disconnect: Whether to do graceful disconnects or not
 *
 * This enabled graceful disconnects on close. A graceful disconnect
 * means that we signal the receiving end that the connection is terminated
 * and wait for it to close the connection before closing the connection.
 *
 * A graceful disconnect means that we can be sure that we successfully sent
 * all the outstanding data to the other end, or get an error reported.
 * However, it also means we have to wait for all the data to reach the
 * other side and for it to acknowledge this by closing the socket, which may
 * take a while. For this reason it is disabled by default.
 *
 * Since: 2.22
 */
void
g_tcp_connection_set_graceful_disconnect (GTcpConnection *connection,
					  gboolean        graceful_disconnect)
{
  graceful_disconnect = !!graceful_disconnect;
  if (graceful_disconnect != connection->priv->graceful_disconnect)
    {
      connection->priv->graceful_disconnect = graceful_disconnect;
      g_object_notify (G_OBJECT (connection), "graceful-disconnect");
    }
}

/**
 * g_tcp_connection_get_graceful_disconnect:
 * @connection: a #GTcpConnection
 *
 * Checks if graceful disconnects are used. See
 * g_tcp_connection_set_graceful_disconnect().
 *
 * Returns: %TRUE if graceful disconnect is used on close, %FALSE otherwise
 *
 * Since: 2.22
 */
gboolean
g_tcp_connection_get_graceful_disconnect (GTcpConnection *connection)
{
  return connection->priv->graceful_disconnect;
}