reactive_socket_service.hpp

这是国外的resip协议栈

      this->get_io_service().post(bind_handler(handler,
            asio::error::bad_descriptor, 0));
    }
    else
    {
      // Make socket non-blocking.
      if (!(impl.flags_ & implementation_type::internal_non_blocking))
      {
        ioctl_arg_type non_blocking = 1;
        asio::error_code ec;
        if (socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ec))
        {
          this->get_io_service().post(bind_handler(handler, ec, 0));
          return;
        }
        impl.flags_ |= implementation_type::internal_non_blocking;
      }

      reactor_.start_read_op(impl.socket_,
          receive_from_handler<MutableBufferSequence, Handler>(
            impl.socket_, this->get_io_service(), buffers,
            sender_endpoint, flags, handler));
    }
  }

  // Accept a new connection.
  template <typename Socket>
  asio::error_code accept(implementation_type& impl,
      Socket& peer, endpoint_type* peer_endpoint, asio::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = asio::error::bad_descriptor;
      return ec;
    }

    // We cannot accept a socket that is already open.
    if (peer.is_open())
    {
      ec = asio::error::already_open;
      return ec;
    }

    // Make socket non-blocking if user wants non-blocking.
    if (impl.flags_ & implementation_type::user_set_non_blocking)
    {
      if (!(impl.flags_ & implementation_type::internal_non_blocking))
      {
        ioctl_arg_type non_blocking = 1;
        if (socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ec))
          return ec;
        impl.flags_ |= implementation_type::internal_non_blocking;
      }
    }

    // Accept a socket.
    for (;;)
    {
      // Try to complete the operation without blocking.
      asio::error_code ec;
      socket_holder new_socket;
      std::size_t addr_len = 0;
      if (peer_endpoint)
      {
        addr_len = peer_endpoint->capacity();
        new_socket.reset(socket_ops::accept(impl.socket_,
              peer_endpoint->data(), &addr_len, ec));
      }
      else
      {
        new_socket.reset(socket_ops::accept(impl.socket_, 0, 0, ec));
      }

      // Check if operation succeeded.
      if (new_socket.get() >= 0)
      {
        if (peer_endpoint)
          peer_endpoint->resize(addr_len);
        peer.assign(impl.protocol_, new_socket.get(), ec);
        if (!ec)
          new_socket.release();
        return ec;
      }

      // Operation failed.
      if (ec == asio::error::would_block
          || ec == asio::error::try_again)
      {
        if (impl.flags_ & implementation_type::user_set_non_blocking)
          return ec;
        // Fall through to retry operation.
      }
      else if (ec == asio::error::connection_aborted)
      {
        if (impl.flags_ & implementation_type::enable_connection_aborted)
          return ec;
        // Fall through to retry operation.
      }
#if defined(EPROTO)
      else if (ec.value() == EPROTO)
      {
        if (impl.flags_ & implementation_type::enable_connection_aborted)
          return ec;
        // Fall through to retry operation.
      }
#endif // defined(EPROTO)
      else
        return ec;

      // Wait for socket to become ready.
      if (socket_ops::poll_read(impl.socket_, ec) < 0)
        return ec;
    }
  }

  template <typename Socket, typename Handler>
  class accept_handler
  {
  public:
    accept_handler(socket_type socket, asio::io_service& io_service,
        Socket& peer, const protocol_type& protocol,
        endpoint_type* peer_endpoint, bool enable_connection_aborted,
        Handler handler)
      : socket_(socket),
        io_service_(io_service),
        work_(io_service),
        peer_(peer),
        protocol_(protocol),
        peer_endpoint_(peer_endpoint),
        enable_connection_aborted_(enable_connection_aborted),
        handler_(handler)
    {
    }

    bool operator()(const asio::error_code& result)
    {
      // Check whether the operation was successful.
      if (result)
      {
        io_service_.post(bind_handler(handler_, result));
        return true;
      }

      // Accept the waiting connection.
      asio::error_code ec;
      socket_holder new_socket;
      std::size_t addr_len = 0;
      if (peer_endpoint_)
      {
        addr_len = peer_endpoint_->capacity();
        new_socket.reset(socket_ops::accept(socket_,
              peer_endpoint_->data(), &addr_len, ec));
      }
      else
      {
        new_socket.reset(socket_ops::accept(socket_, 0, 0, ec));
      }

      // Check if we need to run the operation again.
      if (ec == asio::error::would_block
          || ec == asio::error::try_again)
        return false;
      if (ec == asio::error::connection_aborted
          && !enable_connection_aborted_)
        return false;
#if defined(EPROTO)
      if (ec.value() == EPROTO && !enable_connection_aborted_)
        return false;
#endif // defined(EPROTO)

      // Transfer ownership of the new socket to the peer object.
      if (!ec)
      {
        if (peer_endpoint_)
          peer_endpoint_->resize(addr_len);
        peer_.assign(protocol_, new_socket.get(), ec);
        if (!ec)
          new_socket.release();
      }

      io_service_.post(bind_handler(handler_, ec));
      return true;
    }

  private:
    socket_type socket_;
    asio::io_service& io_service_;
    asio::io_service::work work_;
    Socket& peer_;
    protocol_type protocol_;
    endpoint_type* peer_endpoint_;
    bool enable_connection_aborted_;
    Handler handler_;
  };

  // Start an asynchronous accept. The peer and peer_endpoint objects
  // must be valid until the accept's handler is invoked.
  template <typename Socket, typename Handler>
  void async_accept(implementation_type& impl, Socket& peer,
      endpoint_type* peer_endpoint, Handler handler)
  {
    if (!is_open(impl))
    {
      this->get_io_service().post(bind_handler(handler,
            asio::error::bad_descriptor));
    }
    else if (peer.is_open())
    {
      this->get_io_service().post(bind_handler(handler,
            asio::error::already_open));
    }
    else
    {
      // Make socket non-blocking.
      if (!(impl.flags_ & implementation_type::internal_non_blocking))
      {
        ioctl_arg_type non_blocking = 1;
        asio::error_code ec;
        if (socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ec))
        {
          this->get_io_service().post(bind_handler(handler, ec));
          return;
        }
        impl.flags_ |= implementation_type::internal_non_blocking;
      }

      reactor_.start_read_op(impl.socket_,
          accept_handler<Socket, Handler>(
            impl.socket_, this->get_io_service(),
            peer, impl.protocol_, peer_endpoint,
            (impl.flags_ & implementation_type::enable_connection_aborted) != 0,
            handler));
    }
  }

  // Connect the socket to the specified endpoint.
  asio::error_code connect(implementation_type& impl,
      const endpoint_type& peer_endpoint, asio::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = asio::error::bad_descriptor;
      return ec;
    }

    if (impl.flags_ & implementation_type::internal_non_blocking)
    {
      // Mark the socket as blocking while we perform the connect.
      ioctl_arg_type non_blocking = 0;
      if (socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ec))
        return ec;
      impl.flags_ &= ~implementation_type::internal_non_blocking;
    }

    // Perform the connect operation.
    socket_ops::connect(impl.socket_,
        peer_endpoint.data(), peer_endpoint.size(), ec);
    return ec;
  }

  template <typename Handler>
  class connect_handler
  {
  public:
    connect_handler(socket_type socket, boost::shared_ptr<bool> completed,
        asio::io_service& io_service, Reactor& reactor, Handler handler)
      : socket_(socket),
        completed_(completed),
        io_service_(io_service),
        work_(io_service),
        reactor_(reactor),
        handler_(handler)
    {
    }

    bool operator()(const asio::error_code& result)
    {
      // Check whether a handler has already been called for the connection.
      // If it has, then we don't want to do anything in this handler.
      if (*completed_)
        return true;

      // Cancel the other reactor operation for the connection.
      *completed_ = true;
      reactor_.enqueue_cancel_ops_unlocked(socket_);

      // Check whether the operation was successful.
      if (result)
      {
        io_service_.post(bind_handler(handler_, result));
        return true;
      }

      // Get the error code from the connect operation.
      int connect_error = 0;
      size_t connect_error_len = sizeof(connect_error);
      asio::error_code ec;
      if (socket_ops::getsockopt(socket_, SOL_SOCKET, SO_ERROR,
            &connect_error, &connect_error_len, ec) == socket_error_retval)
      {
        io_service_.post(bind_handler(handler_, ec));
        return true;
      }

      // If connection failed then post the handler with the error code.
      if (connect_error)
      {
        ec = asio::error_code(connect_error,
            asio::error::get_system_category());
        io_service_.post(bind_handler(handler_, ec));
        return true;
      }

      // Post the result of the successful connection operation.
      io_service_.post(bind_handler(handler_, ec));
      return true;
    }

  private:
    socket_type socket_;
    boost::shared_ptr<bool> completed_;
    asio::io_service& io_service_;
    asio::io_service::work work_;
    Reactor& reactor_;
    Handler handler_;
  };

  // Start an asynchronous connect.
  template <typename Handler>
  void async_connect(implementation_type& impl,
      const endpoint_type& peer_endpoint, Handler handler)
  {
    if (!is_open(impl))
    {
      this->get_io_service().post(bind_handler(handler,
            asio::error::bad_descriptor));
      return;
    }

    // Make socket non-blocking.
    if (!(impl.flags_ & implementation_type::internal_non_blocking))
    {
      ioctl_arg_type non_blocking = 1;
      asio::error_code ec;
      if (socket_ops::ioctl(impl.socket_, FIONBIO, &non_blocking, ec))
      {
        this->get_io_service().post(bind_handler(handler, ec));
        return;
      }
      impl.flags_ |= implementation_type::internal_non_blocking;
    }

    // Start the connect operation. The socket is already marked as non-blocking
    // so the connection will take place asynchronously.
    asio::error_code ec;
    if (socket_ops::connect(impl.socket_, peer_endpoint.data(),
          peer_endpoint.size(), ec) == 0)
    {
      // The connect operation has finished successfully so we need to post the
      // handler immediately.
      this->get_io_service().post(bind_handler(handler,
            asio::error_code()));
    }
    else if (ec == asio::error::in_progress
        || ec == asio::error::would_block)
    {
      // The connection is happening in the background, and we need to wait
      // until the socket becomes writeable.
      boost::shared_ptr<bool> completed(new bool(false));
      reactor_.start_write_and_except_ops(impl.socket_,
          connect_handler<Handler>(impl.socket_, completed,
            this->get_io_service(), reactor_, handler));
    }
    else
    {
      // The connect operation has failed, so post the handler immediately.
      this->get_io_service().post(bind_handler(handler, ec));
    }
  }

private:
  // The selector that performs event demultiplexing for the service.
  Reactor& reactor_;
};

} // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_HPP