stream.hpp

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//
// stream.hpp
// ~~~~~~~~~~
//
// Copyright (c) 2005 Voipster / Indrek dot Juhani at voipster dot com
// Copyright (c) 2005 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_SSL_STREAM_HPP
#define ASIO_SSL_STREAM_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/push_options.hpp"

#include "asio/detail/push_options.hpp"
#include <cstddef>
#include <boost/config.hpp>
#include <boost/noncopyable.hpp>
#include <boost/type_traits.hpp>
#include "asio/detail/pop_options.hpp"

#include "asio/error.hpp"
#include "asio/ssl/basic_context.hpp"
#include "asio/ssl/stream_base.hpp"
#include "asio/ssl/stream_service.hpp"
#include "asio/detail/throw_error.hpp"

namespace asio {
namespace ssl {

/// Provides stream-oriented functionality using SSL.
/**
 * The stream class template provides asynchronous and blocking stream-oriented
 * functionality using SSL.
 *
 * @par Thread Safety
 * @e Distinct @e objects: Safe.@n
 * @e Shared @e objects: Unsafe.
 *
 * @par Example
 * To use the SSL stream template with a stream_socket, you would write:
 * @code
 * asio::io_service io_service;
 * asio::ssl::context context(io_service, asio::ssl::context::sslv23);
 * asio::ssl::stream<asio::stream_socket> sock(io_service, context);
 * @endcode
 *
 * @par Concepts:
 * Async_Object, Async_Read_Stream, Async_Write_Stream, Error_Source, Stream,
 * Sync_Read_Stream, Sync_Write_Stream.
 */
template <typename Stream, typename Service = stream_service>
class stream
  : public stream_base,
    private boost::noncopyable
{
public:
  /// The type of the next layer.
  typedef typename boost::remove_reference<Stream>::type next_layer_type;

  /// The type of the lowest layer.
  typedef typename next_layer_type::lowest_layer_type lowest_layer_type;

  /// The type of the service that will be used to provide stream operations.
  typedef Service service_type;

  /// The native implementation type of the stream.
  typedef typename service_type::impl_type impl_type;

  /// Construct a stream.
  /**
   * This constructor creates a stream and initialises the underlying stream
   * object.
   *
   * @param arg The argument to be passed to initialise the underlying stream.
   *
   * @param context The SSL context to be used for the stream.
   */
  template <typename Arg, typename Context_Service>
  explicit stream(Arg& arg, basic_context<Context_Service>& context)
    : next_layer_(arg),
      service_(asio::use_service<Service>(next_layer_.get_io_service())),
      impl_(service_.null())
  {
    service_.create(impl_, next_layer_, context);
  }

  /// Destructor.
  ~stream()
  {
    service_.destroy(impl_, next_layer_);
  }

  /// (Deprecated: use get_io_service().) Get the io_service associated with
  /// the object.
  /**
   * This function may be used to obtain the io_service object that the stream
   * uses to dispatch handlers for asynchronous operations.
   *
   * @return A reference to the io_service object that stream will use to
   * dispatch handlers. Ownership is not transferred to the caller.
   */
  asio::io_service& io_service()
  {
    return next_layer_.get_io_service();
  }

  /// Get the io_service associated with the object.
  /**
   * This function may be used to obtain the io_service object that the stream
   * uses to dispatch handlers for asynchronous operations.
   *
   * @return A reference to the io_service object that stream will use to
   * dispatch handlers. Ownership is not transferred to the caller.
   */
  asio::io_service& get_io_service()
  {
    return next_layer_.get_io_service();
  }

  /// Get a reference to the next layer.
  /**
   * This function returns a reference to the next layer in a stack of stream
   * layers.
   *
   * @return A reference to the next layer in the stack of stream layers.
   * Ownership is not transferred to the caller.
   */
  next_layer_type& next_layer()
  {
    return next_layer_;
  }

  /// Get a reference to the lowest layer.
  /**
   * This function returns a reference to the lowest layer in a stack of
   * stream layers.
   *
   * @return A reference to the lowest layer in the stack of stream layers.
   * Ownership is not transferred to the caller.
   */
  lowest_layer_type& lowest_layer()
  {
    return next_layer_.lowest_layer();
  }

  /// Get the underlying implementation in the native type.
  /**
   * This function may be used to obtain the underlying implementation of the
   * context. This is intended to allow access to stream functionality that is
   * not otherwise provided.
   */
  impl_type impl()
  {
    return impl_;
  }

  /// Perform SSL handshaking.
  /**
   * This function is used to perform SSL handshaking on the stream. The
   * function call will block until handshaking is complete or an error occurs.
   *
   * @param type The type of handshaking to be performed, i.e. as a client or as
   * a server.
   *
   * @throws asio::system_error Thrown on failure.
   */
  void handshake(handshake_type type)
  {
    asio::error_code ec;
    service_.handshake(impl_, next_layer_, type, ec);
    asio::detail::throw_error(ec);
  }

  /// Perform SSL handshaking.
  /**
   * This function is used to perform SSL handshaking on the stream. The
   * function call will block until handshaking is complete or an error occurs.
   *
   * @param type The type of handshaking to be performed, i.e. as a client or as
   * a server.
   *
   * @param ec Set to indicate what error occurred, if any.
   */
  asio::error_code handshake(handshake_type type,
      asio::error_code& ec)
  {
    return service_.handshake(impl_, next_layer_, type, ec);
  }

  /// Start an asynchronous SSL handshake.
  /**
   * This function is used to asynchronously perform an SSL handshake on the
   * stream. This function call always returns immediately.
   *
   * @param type The type of handshaking to be performed, i.e. as a client or as
   * a server.
   *
   * @param handler The handler to be called when the handshake operation
   * completes. Copies will be made of the handler as required. The equivalent
   * function signature of the handler must be:
   * @code void handler(
   *   const asio::error_code& error // Result of operation.
   * ); @endcode
   */
  template <typename HandshakeHandler>
  void async_handshake(handshake_type type, HandshakeHandler handler)
  {
    service_.async_handshake(impl_, next_layer_, type, handler);
  }

  /// Shut down SSL on the stream.
  /**
   * This function is used to shut down SSL on the stream. The function call
   * will block until SSL has been shut down or an error occurs.
   *
   * @throws asio::system_error Thrown on failure.
   */
  void shutdown()
  {
    asio::error_code ec;
    service_.shutdown(impl_, next_layer_, ec);
    asio::detail::throw_error(ec);
  }

  /// Shut down SSL on the stream.
  /**
   * This function is used to shut down SSL on the stream. The function call
   * will block until SSL has been shut down or an error occurs.
   *
   * @param ec Set to indicate what error occurred, if any.
   */
  asio::error_code shutdown(asio::error_code& ec)
  {
    return service_.shutdown(impl_, next_layer_, ec);
  }

  /// Asynchronously shut down SSL on the stream.
  /**
   * This function is used to asynchronously shut down SSL on the stream. This
   * function call always returns immediately.
   *
   * @param handler The handler to be called when the handshake operation
   * completes. Copies will be made of the handler as required. The equivalent
   * function signature of the handler must be:
   * @code void handler(
   *   const asio::error_code& error // Result of operation.