reactive_socket_service.hpp

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//
// reactive_socket_service.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2008 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 BOOST_ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_HPP
#define BOOST_ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_HPP

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

#include <boost/asio/detail/push_options.hpp>

#include <boost/asio/detail/push_options.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/asio/detail/pop_options.hpp>

#include <boost/asio/buffer.hpp>
#include <boost/asio/error.hpp>
#include <boost/asio/io_service.hpp>
#include <boost/asio/socket_base.hpp>
#include <boost/asio/detail/bind_handler.hpp>
#include <boost/asio/detail/handler_base_from_member.hpp>
#include <boost/asio/detail/noncopyable.hpp>
#include <boost/asio/detail/service_base.hpp>
#include <boost/asio/detail/socket_holder.hpp>
#include <boost/asio/detail/socket_ops.hpp>
#include <boost/asio/detail/socket_types.hpp>

namespace boost {
namespace asio {
namespace detail {

template <typename Protocol, typename Reactor>
class reactive_socket_service
  : public boost::asio::detail::service_base<
      reactive_socket_service<Protocol, Reactor> >
{
public:
  // The protocol type.
  typedef Protocol protocol_type;

  // The endpoint type.
  typedef typename Protocol::endpoint endpoint_type;

  // The native type of a socket.
  typedef socket_type native_type;

  // The implementation type of the socket.
  class implementation_type
    : private boost::asio::detail::noncopyable
  {
  public:
    // Default constructor.
    implementation_type()
      : socket_(invalid_socket),
        flags_(0),
        protocol_(endpoint_type().protocol())
    {
    }

  private:
    // Only this service will have access to the internal values.
    friend class reactive_socket_service<Protocol, Reactor>;

    // The native socket representation.
    socket_type socket_;

    enum
    {
      // The user wants a non-blocking socket.
      user_set_non_blocking = 1,

      // The implementation wants a non-blocking socket (in order to be able to
      // perform asynchronous read and write operations).
      internal_non_blocking = 2,

      // Helper "flag" used to determine whether the socket is non-blocking.
      non_blocking = user_set_non_blocking | internal_non_blocking,

      // User wants connection_aborted errors, which are disabled by default.
      enable_connection_aborted = 4,

      // The user set the linger option. Needs to be checked when closing. 
      user_set_linger = 8
    };

    // Flags indicating the current state of the socket.
    unsigned char flags_;

    // The protocol associated with the socket.
    protocol_type protocol_;

    // Per-descriptor data used by the reactor.
    typename Reactor::per_descriptor_data reactor_data_;
  };

  // The maximum number of buffers to support in a single operation.
  enum { max_buffers = 64 < max_iov_len ? 64 : max_iov_len };

  // Constructor.
  reactive_socket_service(boost::asio::io_service& io_service)
    : boost::asio::detail::service_base<
        reactive_socket_service<Protocol, Reactor> >(io_service),
      reactor_(boost::asio::use_service<Reactor>(io_service))
  {
    reactor_.init_task();
  }

  // Destroy all user-defined handler objects owned by the service.
  void shutdown_service()
  {
  }

  // Construct a new socket implementation.
  void construct(implementation_type& impl)
  {
    impl.socket_ = invalid_socket;
    impl.flags_ = 0;
  }

  // Destroy a socket implementation.
  void destroy(implementation_type& impl)
  {
    if (impl.socket_ != invalid_socket)
    {
      reactor_.close_descriptor(impl.socket_, impl.reactor_data_);

      if (impl.flags_ & implementation_type::non_blocking)
      {
        ioctl_arg_type non_blocking = 0;
        boost::system::error_code ignored_ec;
        socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ignored_ec);
        impl.flags_ &= ~implementation_type::non_blocking;
      }

      if (impl.flags_ & implementation_type::user_set_linger)
      {
        ::linger opt;
        opt.l_onoff = 0;
        opt.l_linger = 0;
        boost::system::error_code ignored_ec;
        socket_ops::setsockopt(impl.socket_,
            SOL_SOCKET, SO_LINGER, &opt, sizeof(opt), ignored_ec);
      }

      boost::system::error_code ignored_ec;
      socket_ops::close(impl.socket_, ignored_ec);

      impl.socket_ = invalid_socket;
    }
  }

  // Open a new socket implementation.
  boost::system::error_code open(implementation_type& impl,
      const protocol_type& protocol, boost::system::error_code& ec)
  {
    if (is_open(impl))
    {
      ec = boost::asio::error::already_open;
      return ec;
    }

    socket_holder sock(socket_ops::socket(protocol.family(),
          protocol.type(), protocol.protocol(), ec));
    if (sock.get() == invalid_socket)
      return ec;

    if (int err = reactor_.register_descriptor(sock.get(), impl.reactor_data_))
    {
      ec = boost::system::error_code(err,
          boost::asio::error::get_system_category());
      return ec;
    }

    impl.socket_ = sock.release();
    impl.flags_ = 0;
    impl.protocol_ = protocol;
    ec = boost::system::error_code();
    return ec;
  }

  // Assign a native socket to a socket implementation.
  boost::system::error_code assign(implementation_type& impl,
      const protocol_type& protocol, const native_type& native_socket,
      boost::system::error_code& ec)
  {
    if (is_open(impl))
    {
      ec = boost::asio::error::already_open;
      return ec;
    }

    if (int err = reactor_.register_descriptor(
          native_socket, impl.reactor_data_))
    {
      ec = boost::system::error_code(err,
          boost::asio::error::get_system_category());
      return ec;
    }

    impl.socket_ = native_socket;
    impl.flags_ = 0;
    impl.protocol_ = protocol;
    ec = boost::system::error_code();
    return ec;
  }

  // Determine whether the socket is open.
  bool is_open(const implementation_type& impl) const
  {
    return impl.socket_ != invalid_socket;
  }

  // Destroy a socket implementation.
  boost::system::error_code close(implementation_type& impl,
      boost::system::error_code& ec)
  {
    if (is_open(impl))
    {
      reactor_.close_descriptor(impl.socket_, impl.reactor_data_);

      if (impl.flags_ & implementation_type::non_blocking)
      {
        ioctl_arg_type non_blocking = 0;
        boost::system::error_code ignored_ec;
        socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ignored_ec);
        impl.flags_ &= ~implementation_type::non_blocking;
      }

      if (socket_ops::close(impl.socket_, ec) == socket_error_retval)
        return ec;

      impl.socket_ = invalid_socket;
    }

    ec = boost::system::error_code();
    return ec;
  }

  // Get the native socket representation.
  native_type native(implementation_type& impl)
  {
    return impl.socket_;
  }

  // Cancel all operations associated with the socket.
  boost::system::error_code cancel(implementation_type& impl,
      boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return ec;
    }

    reactor_.cancel_ops(impl.socket_, impl.reactor_data_);
    ec = boost::system::error_code();
    return ec;
  }

  // Determine whether the socket is at the out-of-band data mark.
  bool at_mark(const implementation_type& impl,
      boost::system::error_code& ec) const
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return false;
    }

    boost::asio::detail::ioctl_arg_type value = 0;
    socket_ops::ioctl(impl.socket_, SIOCATMARK, &value, ec);
#if defined(ENOTTY)
    if (ec.value() == ENOTTY)
      ec = boost::asio::error::not_socket;
#endif // defined(ENOTTY)
    return ec ? false : value != 0;
  }

  // Determine the number of bytes available for reading.
  std::size_t available(const implementation_type& impl,
      boost::system::error_code& ec) const
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return 0;
    }

    boost::asio::detail::ioctl_arg_type value = 0;
    socket_ops::ioctl(impl.socket_, FIONREAD, &value, ec);
#if defined(ENOTTY)
    if (ec.value() == ENOTTY)
      ec = boost::asio::error::not_socket;
#endif // defined(ENOTTY)
    return ec ? static_cast<std::size_t>(0) : static_cast<std::size_t>(value);
  }

  // Bind the socket to the specified local endpoint.
  boost::system::error_code bind(implementation_type& impl,
      const endpoint_type& endpoint, boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return ec;
    }

    socket_ops::bind(impl.socket_, endpoint.data(), endpoint.size(), ec);
    return ec;
  }

  // Place the socket into the state where it will listen for new connections.
  boost::system::error_code listen(implementation_type& impl, int backlog,
      boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return ec;
    }

    socket_ops::listen(impl.socket_, backlog, ec);
    return ec;
  }

  // Set a socket option.
  template <typename Option>
  boost::system::error_code set_option(implementation_type& impl,
      const Option& option, boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return ec;
    }

    if (option.level(impl.protocol_) == custom_socket_option_level
        && option.name(impl.protocol_) == enable_connection_aborted_option)
    {
      if (option.size(impl.protocol_) != sizeof(int))
      {
        ec = boost::asio::error::invalid_argument;
      }
      else
      {
        if (*reinterpret_cast<const int*>(option.data(impl.protocol_)))
          impl.flags_ |= implementation_type::enable_connection_aborted;
        else
          impl.flags_ &= ~implementation_type::enable_connection_aborted;
        ec = boost::system::error_code();
      }
      return ec;
    }
    else
    {
      if (option.level(impl.protocol_) == SOL_SOCKET
          && option.name(impl.protocol_) == SO_LINGER)
      {
        impl.flags_ |= implementation_type::user_set_linger;
      }

      socket_ops::setsockopt(impl.socket_,
          option.level(impl.protocol_), option.name(impl.protocol_),
          option.data(impl.protocol_), option.size(impl.protocol_), ec);

#if defined(__MACH__) && defined(__APPLE__) \
|| defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
      // To implement portable behaviour for SO_REUSEADDR with UDP sockets we
      // need to also set SO_REUSEPORT on BSD-based platforms.
      if (!ec && impl.protocol_.type() == SOCK_DGRAM
          && option.level(impl.protocol_) == SOL_SOCKET
          && option.name(impl.protocol_) == SO_REUSEADDR)
      {
        boost::system::error_code ignored_ec;
        socket_ops::setsockopt(impl.socket_, SOL_SOCKET, SO_REUSEPORT,
            option.data(impl.protocol_), option.size(impl.protocol_),
            ignored_ec);
      }
#endif

      return ec;
    }
  }

  // Set a socket option.
  template <typename Option>
  boost::system::error_code get_option(const implementation_type& impl,
      Option& option, boost::system::error_code& ec) const
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return ec;
    }

    if (option.level(impl.protocol_) == custom_socket_option_level
        && option.name(impl.protocol_) == enable_connection_aborted_option)
    {
      if (option.size(impl.protocol_) != sizeof(int))
      {
        ec = boost::asio::error::invalid_argument;
      }
      else
      {
        int* target = reinterpret_cast<int*>(option.data(impl.protocol_));
        if (impl.flags_ & implementation_type::enable_connection_aborted)
          *target = 1;
        else
          *target = 0;
        option.resize(impl.protocol_, sizeof(int));
        ec = boost::system::error_code();
      }
      return ec;
    }
    else
    {
      size_t size = option.size(impl.protocol_);
      socket_ops::getsockopt(impl.socket_,
          option.level(impl.protocol_), option.name(impl.protocol_),
          option.data(impl.protocol_), &size, ec);
      if (!ec)
        option.resize(impl.protocol_, size);
      return ec;
    }
  }

  // Perform an IO control command on the socket.
  template <typename IO_Control_Command>
  boost::system::error_code io_control(implementation_type& impl,
      IO_Control_Command& command, boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return ec;
    }

    if (command.name() == static_cast<int>(FIONBIO))
    {
      // Flags are manipulated in a temporary variable so that the socket