win_iocp_socket_service.hpp

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  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return 0;
    }

    // Copy buffers into WSABUF array.
    ::WSABUF bufs[max_buffers];
    typename MutableBufferSequence::const_iterator iter = buffers.begin();
    typename MutableBufferSequence::const_iterator end = buffers.end();
    DWORD i = 0;
    size_t total_buffer_size = 0;
    for (; iter != end && i < max_buffers; ++iter, ++i)
    {
      boost::asio::mutable_buffer buffer(*iter);
      bufs[i].len = static_cast<u_long>(boost::asio::buffer_size(buffer));
      bufs[i].buf = boost::asio::buffer_cast<char*>(buffer);
      total_buffer_size += boost::asio::buffer_size(buffer);
    }

    // A request to receive 0 bytes on a stream socket is a no-op.
    if (impl.protocol_.type() == SOCK_STREAM && total_buffer_size == 0)
    {
      ec = boost::system::error_code();
      return 0;
    }

    // Receive some data.
    DWORD bytes_transferred = 0;
    DWORD recv_flags = flags;
    int result = ::WSARecv(impl.socket_, bufs, i,
        &bytes_transferred, &recv_flags, 0, 0);
    if (result != 0)
    {
      DWORD last_error = ::WSAGetLastError();
      if (last_error == ERROR_NETNAME_DELETED)
        last_error = WSAECONNRESET;
      else if (last_error == ERROR_PORT_UNREACHABLE)
        last_error = WSAECONNREFUSED;
      ec = boost::system::error_code(last_error,
          boost::asio::error::get_system_category());
      return 0;
    }
    if (bytes_transferred == 0 && impl.protocol_.type() == SOCK_STREAM)
    {
      ec = boost::asio::error::eof;
      return 0;
    }

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

  // Wait until data can be received without blocking.
  size_t receive(implementation_type& impl, const null_buffers&,
      socket_base::message_flags, boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return 0;
    }

    // Wait for socket to become ready.
    socket_ops::poll_read(impl.socket_, ec);

    return 0;
  }

  template <typename MutableBufferSequence, typename Handler>
  class receive_operation
    : public operation
  {
  public:
    receive_operation(int protocol_type, win_iocp_io_service& io_service,
        weak_cancel_token_type cancel_token,
        const MutableBufferSequence& buffers, Handler handler)
      : operation(io_service,
          &receive_operation<
            MutableBufferSequence, Handler>::do_completion_impl,
          &receive_operation<
            MutableBufferSequence, Handler>::destroy_impl),
        protocol_type_(protocol_type),
        work_(io_service.get_io_service()),
        cancel_token_(cancel_token),
        buffers_(buffers),
        handler_(handler)
    {
    }

  private:
    static void do_completion_impl(operation* op,
        DWORD last_error, size_t bytes_transferred)
    {
      // Take ownership of the operation object.
      typedef receive_operation<MutableBufferSequence, Handler> op_type;
      op_type* handler_op(static_cast<op_type*>(op));
      typedef handler_alloc_traits<Handler, op_type> alloc_traits;
      handler_ptr<alloc_traits> ptr(handler_op->handler_, handler_op);

#if defined(BOOST_ASIO_ENABLE_BUFFER_DEBUGGING)
      // Check whether buffers are still valid.
      typename MutableBufferSequence::const_iterator iter
        = handler_op->buffers_.begin();
      typename MutableBufferSequence::const_iterator end
        = handler_op->buffers_.end();
      while (iter != end)
      {
        boost::asio::mutable_buffer buffer(*iter);
        boost::asio::buffer_cast<char*>(buffer);
        ++iter;
      }
#endif // defined(BOOST_ASIO_ENABLE_BUFFER_DEBUGGING)

      // Map non-portable errors to their portable counterparts.
      boost::system::error_code ec(last_error,
          boost::asio::error::get_system_category());
      if (ec.value() == ERROR_NETNAME_DELETED)
      {
        if (handler_op->cancel_token_.expired())
          ec = boost::asio::error::operation_aborted;
        else
          ec = boost::asio::error::connection_reset;
      }
      else if (ec.value() == ERROR_PORT_UNREACHABLE)
      {
        ec = boost::asio::error::connection_refused;
      }

      // Check for connection closed.
      else if (!ec && bytes_transferred == 0
          && handler_op->protocol_type_ == SOCK_STREAM
          && !boost::is_same<MutableBufferSequence, null_buffers>::value)
      {
        ec = boost::asio::error::eof;
      }

      // Make a copy of the handler so that the memory can be deallocated before
      // the upcall is made.
      Handler handler(handler_op->handler_);

      // Free the memory associated with the handler.
      ptr.reset();

      // Call the handler.
      boost_asio_handler_invoke_helpers::invoke(
          detail::bind_handler(handler, ec, bytes_transferred), &handler);
    }

    static void destroy_impl(operation* op)
    {
      // Take ownership of the operation object.
      typedef receive_operation<MutableBufferSequence, Handler> op_type;
      op_type* handler_op(static_cast<op_type*>(op));
      typedef handler_alloc_traits<Handler, op_type> alloc_traits;
      handler_ptr<alloc_traits> ptr(handler_op->handler_, handler_op);

      // A sub-object of the handler may be the true owner of the memory
      // associated with the handler. Consequently, a local copy of the handler
      // is required to ensure that any owning sub-object remains valid until
      // after we have deallocated the memory here.
      Handler handler(handler_op->handler_);
      (void)handler;

      // Free the memory associated with the handler.
      ptr.reset();
    }

    int protocol_type_;
    boost::asio::io_service::work work_;
    weak_cancel_token_type cancel_token_;
    MutableBufferSequence buffers_;
    Handler handler_;
  };

  // Start an asynchronous receive. The buffer for the data being received
  // must be valid for the lifetime of the asynchronous operation.
  template <typename MutableBufferSequence, typename Handler>
  void async_receive(implementation_type& impl,
      const MutableBufferSequence& buffers,
      socket_base::message_flags flags, Handler handler)
  {
    if (!is_open(impl))
    {
      this->get_io_service().post(bind_handler(handler,
            boost::asio::error::bad_descriptor, 0));
      return;
    }

#if defined(BOOST_ASIO_ENABLE_CANCELIO)
    // Update the ID of the thread from which cancellation is safe.
    if (impl.safe_cancellation_thread_id_ == 0)
      impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId();
    else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId())
      impl.safe_cancellation_thread_id_ = ~DWORD(0);
#endif // defined(BOOST_ASIO_ENABLE_CANCELIO)

    // Allocate and construct an operation to wrap the handler.
    typedef receive_operation<MutableBufferSequence, Handler> value_type;
    typedef handler_alloc_traits<Handler, value_type> alloc_traits;
    raw_handler_ptr<alloc_traits> raw_ptr(handler);
    int protocol_type = impl.protocol_.type();
    handler_ptr<alloc_traits> ptr(raw_ptr, protocol_type,
        iocp_service_, impl.cancel_token_, buffers, handler);

    // Copy buffers into WSABUF array.
    ::WSABUF bufs[max_buffers];
    typename MutableBufferSequence::const_iterator iter = buffers.begin();
    typename MutableBufferSequence::const_iterator end = buffers.end();
    DWORD i = 0;
    size_t total_buffer_size = 0;
    for (; iter != end && i < max_buffers; ++iter, ++i)
    {
      boost::asio::mutable_buffer buffer(*iter);
      bufs[i].len = static_cast<u_long>(boost::asio::buffer_size(buffer));
      bufs[i].buf = boost::asio::buffer_cast<char*>(buffer);
      total_buffer_size += boost::asio::buffer_size(buffer);
    }

    // A request to receive 0 bytes on a stream socket is a no-op.
    if (impl.protocol_.type() == SOCK_STREAM && total_buffer_size == 0)
    {
      boost::asio::io_service::work work(this->get_io_service());
      ptr.reset();
      boost::system::error_code error;
      iocp_service_.post(bind_handler(handler, error, 0));
      return;
    }

    // Receive some data.
    DWORD bytes_transferred = 0;
    DWORD recv_flags = flags;
    int result = ::WSARecv(impl.socket_, bufs, i,
        &bytes_transferred, &recv_flags, ptr.get(), 0);
    DWORD last_error = ::WSAGetLastError();
    if (result != 0 && last_error != WSA_IO_PENDING)
    {
      boost::asio::io_service::work work(this->get_io_service());
      ptr.reset();
      boost::system::error_code ec(last_error,
          boost::asio::error::get_system_category());
      iocp_service_.post(bind_handler(handler, ec, bytes_transferred));
    }
    else
    {
      ptr.release();
    }
  }

  // Wait until data can be received without blocking.
  template <typename Handler>
  void async_receive(implementation_type& impl, const null_buffers& buffers,
      socket_base::message_flags flags, Handler handler)
  {
    if (!is_open(impl))
    {
      this->get_io_service().post(bind_handler(handler,
            boost::asio::error::bad_descriptor, 0));
    }
    else if (impl.protocol_.type() == SOCK_STREAM)
    {
      // For stream sockets on Windows, we may issue a 0-byte overlapped
      // WSARecv to wait until there is data available on the socket.

#if defined(BOOST_ASIO_ENABLE_CANCELIO)
      // Update the ID of the thread from which cancellation is safe.
      if (impl.safe_cancellation_thread_id_ == 0)
        impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId();
      else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId())
        impl.safe_cancellation_thread_id_ = ~DWORD(0);
#endif // defined(BOOST_ASIO_ENABLE_CANCELIO)

      // Allocate and construct an operation to wrap the handler.
      typedef receive_operation<null_buffers, Handler> value_type;
      typedef handler_alloc_traits<Handler, value_type> alloc_traits;
      raw_handler_ptr<alloc_traits> raw_ptr(handler);
      int protocol_type = impl.protocol_.type();
      handler_ptr<alloc_traits> ptr(raw_ptr, protocol_type,
          iocp_service_, impl.cancel_token_, buffers, handler);

      // Issue a receive operation with an empty buffer.
      ::WSABUF buf = { 0, 0 };
      DWORD bytes_transferred = 0;
      DWORD recv_flags = flags;
      int result = ::WSARecv(impl.socket_, &buf, 1,
          &bytes_transferred, &recv_flags, ptr.get(), 0);
      DWORD last_error = ::WSAGetLastError();
      if (result != 0 && last_error != WSA_IO_PENDING)
      {
        boost::asio::io_service::work work(this->get_io_service());
        ptr.reset();
        boost::system::error_code ec(last_error,
            boost::asio::error::get_system_category());
        iocp_service_.post(bind_handler(handler, ec, bytes_transferred));
      }
      else
      {
        ptr.release();
      }
    }
    else
    {
      // Check if the reactor was already obtained from the io_service.
      reactor_type* reactor = static_cast<reactor_type*>(
            interlocked_compare_exchange_pointer(
              reinterpret_cast<void**>(&reactor_), 0, 0));
      if (!reactor)
      {
        reactor = &(boost::asio::use_service<reactor_type>(
              this->get_io_service()));
        interlocked_exchange_pointer(
            reinterpret_cast<void**>(&reactor_), reactor);
      }

      if (flags & socket_base::message_out_of_band)
      {
        reactor->start_except_op(impl.socket_, impl.reactor_data_,
            null_buffers_operation<Handler>(this->get_io_service(), handler));
      }
      else
      {
        reactor->start_read_op(impl.socket_, impl.reactor_data_,
            null_buffers_operation<Handler>(this->get_io_service(), handler),
            false);
      }
    }
  }

  // Receive a datagram with the endpoint of the sender. Returns the number of
  // bytes received.
  template <typename MutableBufferSequence>
  size_t receive_from(implementation_type& impl,
      const MutableBufferSequence& buffers,
      endpoint_type& sender_endpoint, socket_base::message_flags flags,
      boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return 0;
    }

    // Copy buffers into WSABUF array.
    ::WSABUF bufs[max_buffers];
    typename MutableBufferSequence::const_iterator iter = buffers.begin();
    typename MutableBufferSequence::const_iterator end = buffers.end();
    DWORD i = 0;
    for (; iter != end && i < max_buffers; ++iter, ++i)
    {
      boost::asio::mutable_buffer buffer(*iter);
      bufs[i].len = static_cast<u_long>(boost::asio::buffer_size(buffer));
      bufs[i].buf = boost::asio::buffer_cast<char*>(buffer);
    }

    // Receive some data.
    DWORD bytes_transferred = 0;
    DWORD recv_flags = flags;
    int endpoint_size = static_cast<int>(sender_endpoint.capacity());
    int result = ::WSARecvFrom(impl.socket_, bufs, i, &bytes_transferred,
        &recv_flags, sender_endpoint.data(), &endpoint_size, 0, 0);
    if (result != 0)
    {
      DWORD last_error = ::WSAGetLastError();
      if (last_error == ERROR_PORT_UNREACHABLE)
        last_error = WSAECONNREFUSED;
      ec = boost::system::error_code(last_error,
          boost::asio::error::get_system_category());
      return 0;
    }
    if (bytes_transferred == 0 && impl.protocol_.type() == SOCK_STREAM)
    {
      ec = boost::asio::error::eof;
      return 0;
    }

    sender_endpoint.resize(static_cast<std::size_t>(endpoint_size));

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

  // Wait until data can be received without blocking.
  size_t receive_from(implementation_type& impl,
      const null_buffers&, endpoint_type& sender_endpoint,
      socket_base::message_flags, boost::system::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = boost::asio::error::bad_descriptor;
      return 0;
    }

    // Wait for socket to become ready.
    socket_ops::poll_read(impl.socket_, ec);

    // Reset endpoint since it can be given no sensible value at this time.
    sender_endpoint = endpoint_type();