connect.hpp

//
// execution/connect.hpp
// ~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 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_EXECUTION_CONNECT_HPP
#define ASIO_EXECUTION_CONNECT_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/type_traits.hpp"
#include "asio/execution/detail/as_invocable.hpp"
#include "asio/execution/detail/as_operation.hpp"
#include "asio/execution/detail/as_receiver.hpp"
#include "asio/execution/executor.hpp"
#include "asio/execution/operation_state.hpp"
#include "asio/execution/receiver.hpp"
#include "asio/execution/sender.hpp"
#include "asio/traits/connect_member.hpp"
#include "asio/traits/connect_free.hpp"

#include "asio/detail/push_options.hpp"

#if defined(GENERATING_DOCUMENTATION)

namespace asio {
namespace execution {


inline constexpr unspecified connect = unspecified;


template <typename S, typename R>
struct can_connect :
  integral_constant<bool, automatically_determined>
{
};

template <typename S, typename R>
struct connect_result
{

  typedef automatically_determined type;
};

template <typename S, typename R>
using connect_result_t = typename connect_result<S, R>::type;

} // namespace execution
} // namespace asio

#else // defined(GENERATING_DOCUMENTATION)

namespace asio_execution_connect_fn {

using asio::conditional;
using asio::declval;
using asio::enable_if;
using asio::execution::detail::as_invocable;
using asio::execution::detail::as_operation;
using asio::execution::detail::is_as_receiver;
using asio::execution::is_executor_of;
using asio::execution::is_operation_state;
using asio::execution::is_receiver;
using asio::execution::is_sender;
using asio::false_type;
using asio::remove_cvref;
using asio::traits::connect_free;
using asio::traits::connect_member;

void connect();

enum overload_type
{
  call_member,
  call_free,
  adapter,
  ill_formed
};

template <typename S, typename R, typename = void>
struct call_traits
{
  ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed);
  ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
  typedef void result_type;
};

template <typename S, typename R>
struct call_traits<S, void(R),
  typename enable_if<
    (
      connect_member<S, R>::is_valid
      &&
      is_operation_state<typename connect_member<S, R>::result_type>::value
      &&
      is_sender<typename remove_cvref<S>::type>::value
    )
  >::type> :
  connect_member<S, R>
{
  ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
};

template <typename S, typename R>
struct call_traits<S, void(R),
  typename enable_if<
    (
      !connect_member<S, R>::is_valid
      &&
      connect_free<S, R>::is_valid
      &&
      is_operation_state<typename connect_free<S, R>::result_type>::value
      &&
      is_sender<typename remove_cvref<S>::type>::value
    )
  >::type> :
  connect_free<S, R>
{
  ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
};

template <typename S, typename R>
struct call_traits<S, void(R),
  typename enable_if<
    (
      !connect_member<S, R>::is_valid
      &&
      !connect_free<S, R>::is_valid
      &&
      is_receiver<R>::value
      &&
      conditional<
        !is_as_receiver<
          typename remove_cvref<R>::type
        >::value,
        is_executor_of<
          typename remove_cvref<S>::type,
          as_invocable<typename remove_cvref<R>::type, S>
        >,
        false_type
      >::type::value
    )
  >::type>
{
  ASIO_STATIC_CONSTEXPR(overload_type, overload = adapter);
  ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
  typedef as_operation<S, R> result_type;
};

struct impl
{
#if defined(ASIO_HAS_MOVE)
  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S, void(R)>::overload == call_member,
    typename call_traits<S, void(R)>::result_type
  >::type
  operator()(S&& s, R&& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S, void(R)>::is_noexcept))
  {
    return ASIO_MOVE_CAST(S)(s).connect(ASIO_MOVE_CAST(R)(r));
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S, void(R)>::overload == call_free,
    typename call_traits<S, void(R)>::result_type
  >::type
  operator()(S&& s, R&& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S, void(R)>::is_noexcept))
  {
    return connect(ASIO_MOVE_CAST(S)(s), ASIO_MOVE_CAST(R)(r));
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S, void(R)>::overload == adapter,
    typename call_traits<S, void(R)>::result_type
  >::type
  operator()(S&& s, R&& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S, void(R)>::is_noexcept))
  {
    return typename call_traits<S, void(R)>::result_type(
        ASIO_MOVE_CAST(S)(s), ASIO_MOVE_CAST(R)(r));
  }
#else // defined(ASIO_HAS_MOVE)
  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S&, void(R&)>::overload == call_member,
    typename call_traits<S&, void(R&)>::result_type
  >::type
  operator()(S& s, R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S&, void(R&)>::is_noexcept))
  {
    return s.connect(r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<const S&, void(R&)>::overload == call_member,
    typename call_traits<const S&, void(R&)>::result_type
  >::type
  operator()(const S& s, R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<const S&, void(R&)>::is_noexcept))
  {
    return s.connect(r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S&, void(R&)>::overload == call_free,
    typename call_traits<S&, void(R&)>::result_type
  >::type
  operator()(S& s, R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S&, void(R&)>::is_noexcept))
  {
    return connect(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<const S&, void(R&)>::overload == call_free,
    typename call_traits<const S&, void(R&)>::result_type
  >::type
  operator()(const S& s, R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<const S&, void(R&)>::is_noexcept))
  {
    return connect(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S&, void(R&)>::overload == adapter,
    typename call_traits<S&, void(R&)>::result_type
  >::type
  operator()(S& s, R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S&, void(R&)>::is_noexcept))
  {
    return typename call_traits<S&, void(R&)>::result_type(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<const S&, void(R&)>::overload == adapter,
    typename call_traits<const S&, void(R&)>::result_type
  >::type
  operator()(const S& s, R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<const S&, void(R&)>::is_noexcept))
  {
    return typename call_traits<const S&, void(R&)>::result_type(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S&, void(const R&)>::overload == call_member,
    typename call_traits<S&, void(const R&)>::result_type
  >::type
  operator()(S& s, const R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S&, void(const R&)>::is_noexcept))
  {
    return s.connect(r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<const S&, void(const R&)>::overload == call_member,
    typename call_traits<const S&, void(const R&)>::result_type
  >::type
  operator()(const S& s, const R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<const S&, void(const R&)>::is_noexcept))
  {
    return s.connect(r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S&, void(const R&)>::overload == call_free,
    typename call_traits<S&, void(const R&)>::result_type
  >::type
  operator()(S& s, const R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S&, void(const R&)>::is_noexcept))
  {
    return connect(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<const S&, void(const R&)>::overload == call_free,
    typename call_traits<const S&, void(const R&)>::result_type
  >::type
  operator()(const S& s, const R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<const S&, void(const R&)>::is_noexcept))
  {
    return connect(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<S&, void(const R&)>::overload == adapter,
    typename call_traits<S&, void(const R&)>::result_type
  >::type
  operator()(S& s, const R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<S&, void(const R&)>::is_noexcept))
  {
    return typename call_traits<S&, void(const R&)>::result_type(s, r);
  }

  template <typename S, typename R>
  ASIO_CONSTEXPR typename enable_if<
    call_traits<const S&, void(const R&)>::overload == adapter,
    typename call_traits<const S&, void(const R&)>::result_type
  >::type
  operator()(const S& s, const R& r) const
    ASIO_NOEXCEPT_IF((
      call_traits<const S&, void(const R&)>::is_noexcept))
  {
    return typename call_traits<const S&, void(const R&)>::result_type(s, r);
  }
#endif // defined(ASIO_HAS_MOVE)
};

template <typename T = impl>
struct static_instance
{
  static const T instance;
};

template <typename T>
const T static_instance<T>::instance = {};

} // namespace asio_execution_connect_fn
namespace asio {
namespace execution {
namespace {

static ASIO_CONSTEXPR const asio_execution_connect_fn::impl&
  connect = asio_execution_connect_fn::static_instance<>::instance;

} // namespace

template <typename S, typename R>
struct can_connect :
  integral_constant<bool,
    asio_execution_connect_fn::call_traits<S, void(R)>::overload !=
      asio_execution_connect_fn::ill_formed>
{
};

#if defined(ASIO_HAS_VARIABLE_TEMPLATES)

template <typename S, typename R>
constexpr bool can_connect_v = can_connect<S, R>::value;

#endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)

template <typename S, typename R>
struct is_nothrow_connect :
  integral_constant<bool,
    asio_execution_connect_fn::call_traits<S, void(R)>::is_noexcept>
{
};

#if defined(ASIO_HAS_VARIABLE_TEMPLATES)

template <typename S, typename R>
constexpr bool is_nothrow_connect_v
  = is_nothrow_connect<S, R>::value;

#endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)

template <typename S, typename R>
struct connect_result
{
  typedef typename asio_execution_connect_fn::call_traits<
      S, void(R)>::result_type type;
};

#if defined(ASIO_HAS_ALIAS_TEMPLATES)

template <typename S, typename R>
using connect_result_t = typename connect_result<S, R>::type;

#endif // defined(ASIO_HAS_ALIAS_TEMPLATES)

} // namespace execution
} // namespace asio

#endif // defined(GENERATING_DOCUMENTATION)

#include "asio/detail/pop_options.hpp"

#endif // ASIO_EXECUTION_CONNECT_HPP