text: //
  // detail/reactive_socket_accept_op.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2019 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_DETAIL_REACTIVE_SOCKET_ACCEPT_OP_HPP
  #define ASIO_DETAIL_REACTIVE_SOCKET_ACCEPT_OP_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include "asio/detail/config.hpp"
  #include "asio/detail/bind_handler.hpp"
  #include "asio/detail/buffer_sequence_adapter.hpp"
  #include "asio/detail/fenced_block.hpp"
  #include "asio/detail/memory.hpp"
  #include "asio/detail/reactor_op.hpp"
  #include "asio/detail/socket_holder.hpp"
  #include "asio/detail/socket_ops.hpp"
  
  #include "asio/detail/push_options.hpp"
  
  namespace asio {
  namespace detail {
  
  template <typename Socket, typename Protocol>
  class reactive_socket_accept_op_base : public reactor_op
  {
  public:
    reactive_socket_accept_op_base(socket_type socket,
        socket_ops::state_type state, Socket& peer, const Protocol& protocol,
        typename Protocol::endpoint* peer_endpoint, func_type complete_func)
      : reactor_op(&reactive_socket_accept_op_base::do_perform, complete_func),
        socket_(socket),
        state_(state),
        peer_(peer),
        protocol_(protocol),
        peer_endpoint_(peer_endpoint),
        addrlen_(peer_endpoint ? peer_endpoint->capacity() : 0)
    {
    }
  
    static status do_perform(reactor_op* base)
    {
      reactive_socket_accept_op_base* o(
          static_cast<reactive_socket_accept_op_base*>(base));
  
      socket_type new_socket = invalid_socket;
      status result = socket_ops::non_blocking_accept(o->socket_,
          o->state_, o->peer_endpoint_ ? o->peer_endpoint_->data() : 0,
          o->peer_endpoint_ ? &o->addrlen_ : 0, o->ec_, new_socket)
      ? done : not_done;
      o->new_socket_.reset(new_socket);
  
      ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_accept", o->ec_));
  
      return result;
    }
  
    void do_assign()
    {
      if (new_socket_.get() != invalid_socket)
      {
        if (peer_endpoint_)
          peer_endpoint_->resize(addrlen_);
        peer_.assign(protocol_, new_socket_.get(), ec_);
        if (!ec_)
          new_socket_.release();
      }
    }
  
  private:
    socket_type socket_;
    socket_ops::state_type state_;
    socket_holder new_socket_;
    Socket& peer_;
    Protocol protocol_;
    typename Protocol::endpoint* peer_endpoint_;
    std::size_t addrlen_;
  };
  
  template <typename Socket, typename Protocol,
      typename Handler, typename IoExecutor>
  class reactive_socket_accept_op :
    public reactive_socket_accept_op_base<Socket, Protocol>
  {
  public:
    ASIO_DEFINE_HANDLER_PTR(reactive_socket_accept_op);
  
    reactive_socket_accept_op(socket_type socket,
        socket_ops::state_type state, Socket& peer, const Protocol& protocol,
        typename Protocol::endpoint* peer_endpoint, Handler& handler,
        const IoExecutor& io_ex)
      : reactive_socket_accept_op_base<Socket, Protocol>(socket, state, peer,
          protocol, peer_endpoint, &reactive_socket_accept_op::do_complete),
        handler_(ASIO_MOVE_CAST(Handler)(handler)),
        io_executor_(io_ex)
    {
      handler_work<Handler, IoExecutor>::start(handler_, io_executor_);
    }
  
    static void do_complete(void* owner, operation* base,
        const asio::error_code& /*ec*/,
        std::size_t /*bytes_transferred*/)
    {
      // Take ownership of the handler object.
      reactive_socket_accept_op* o(static_cast<reactive_socket_accept_op*>(base));
      ptr p = { asio::detail::addressof(o->handler_), o, o };
      handler_work<Handler, IoExecutor> w(o->handler_, o->io_executor_);
  
      // On success, assign new connection to peer socket object.
      if (owner)
        o->do_assign();
  
      ASIO_HANDLER_COMPLETION((*o));
  
      // Make a copy of the handler so that the memory can be deallocated before
      // the upcall is made. Even if we're not about to make an upcall, 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.
      detail::binder1<Handler, asio::error_code>
        handler(o->handler_, o->ec_);
      p.h = asio::detail::addressof(handler.handler_);
      p.reset();
  
      // Make the upcall if required.
      if (owner)
      {
        fenced_block b(fenced_block::half);
        ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
        w.complete(handler, handler.handler_);
        ASIO_HANDLER_INVOCATION_END;
      }
    }
  
  private:
    Handler handler_;
    IoExecutor io_executor_;
  };
  
  #if defined(ASIO_HAS_MOVE)
  
  template <typename Protocol, typename PeerIoExecutor,
      typename Handler, typename IoExecutor>
  class reactive_socket_move_accept_op :
    private Protocol::socket::template rebind_executor<PeerIoExecutor>::other,
    public reactive_socket_accept_op_base<
      typename Protocol::socket::template rebind_executor<PeerIoExecutor>::other,
      Protocol>
  {
  public:
    ASIO_DEFINE_HANDLER_PTR(reactive_socket_move_accept_op);
  
    reactive_socket_move_accept_op(const PeerIoExecutor& peer_io_ex,
        socket_type socket, socket_ops::state_type state,
        const Protocol& protocol, typename Protocol::endpoint* peer_endpoint,
        Handler& handler, const IoExecutor& io_ex)
      : peer_socket_type(peer_io_ex),
        reactive_socket_accept_op_base<peer_socket_type, Protocol>(
          socket, state, *this, protocol, peer_endpoint,
          &reactive_socket_move_accept_op::do_complete),
        handler_(ASIO_MOVE_CAST(Handler)(handler)),
        io_executor_(io_ex)
    {
      handler_work<Handler, IoExecutor>::start(handler_, io_executor_);
    }
  
    static void do_complete(void* owner, operation* base,
        const asio::error_code& /*ec*/,
        std::size_t /*bytes_transferred*/)
    {
      // Take ownership of the handler object.
      reactive_socket_move_accept_op* o(
          static_cast<reactive_socket_move_accept_op*>(base));
      ptr p = { asio::detail::addressof(o->handler_), o, o };
      handler_work<Handler, IoExecutor> w(o->handler_, o->io_executor_);
  
      // On success, assign new connection to peer socket object.
      if (owner)
        o->do_assign();
  
      ASIO_HANDLER_COMPLETION((*o));
  
      // Make a copy of the handler so that the memory can be deallocated before
      // the upcall is made. Even if we're not about to make an upcall, 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.
      detail::move_binder2<Handler,
        asio::error_code, peer_socket_type>
          handler(0, ASIO_MOVE_CAST(Handler)(o->handler_), o->ec_,
            ASIO_MOVE_CAST(peer_socket_type)(*o));
      p.h = asio::detail::addressof(handler.handler_);
      p.reset();
  
      // Make the upcall if required.
      if (owner)
      {
        fenced_block b(fenced_block::half);
        ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
        w.complete(handler, handler.handler_);
        ASIO_HANDLER_INVOCATION_END;
      }
    }
  
  private:
    typedef typename Protocol::socket::template
      rebind_executor<PeerIoExecutor>::other peer_socket_type;
  
    Handler handler_;
    IoExecutor io_executor_;
  };
  
  #endif // defined(ASIO_HAS_MOVE)
  
  } // namespace detail
  } // namespace asio
  
  #include "asio/detail/pop_options.hpp"
  
  #endif // ASIO_DETAIL_REACTIVE_SOCKET_ACCEPT_OP_HPP
  