boost/beast/core/detail/work_guard.hpp
//
// Copyright (c) 2020 Richard Hodges (hodges.r@gmail.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)
//
// Official repository: https://github.com/boostorg/beast
//
#ifndef BOOST_BEAST_CORE_DETAIL_WORK_GUARD_HPP
#define BOOST_BEAST_CORE_DETAIL_WORK_GUARD_HPP
#include <boost/asio/executor_work_guard.hpp>
#include <boost/asio/execution.hpp>
#include <boost/optional.hpp>
namespace boost {
namespace beast {
namespace detail {
template<class Executor, class Enable = void>
struct select_work_guard;
template<class Executor>
using select_work_guard_t = typename
select_work_guard<Executor>::type;
#if !defined(BOOST_ASIO_NO_TS_EXECUTORS)
template<class Executor>
struct select_work_guard
<
Executor,
typename std::enable_if
<
net::is_executor<Executor>::value
>::type
>
{
using type = net::executor_work_guard<Executor>;
};
#endif
template<class Executor>
struct execution_work_guard
{
using executor_type = typename std::decay<decltype(
net::prefer(std::declval<Executor const&>(),
net::execution::outstanding_work.tracked))>::type;
execution_work_guard(Executor const& exec)
: ex_(net::prefer(exec, net::execution::outstanding_work.tracked))
{
}
executor_type
get_executor() const noexcept
{
BOOST_ASSERT(ex_.has_value());
return *ex_;
}
void reset() noexcept
{
ex_.reset();
}
private:
boost::optional<executor_type> ex_;
};
template<class Executor>
struct select_work_guard
<
Executor,
typename std::enable_if
<
net::execution::is_executor<Executor>::value
#if defined(BOOST_ASIO_NO_TS_EXECUTORS)
|| net::is_executor<Executor>::value
#else
&& !net::is_executor<Executor>::value
#endif
>::type
>
{
using type = execution_work_guard<Executor>;
};
template<class Executor>
select_work_guard_t<Executor>
make_work_guard(Executor const& exec) noexcept
{
return select_work_guard_t<Executor>(exec);
}
}
}
}
#endif // BOOST_BEAST_CORE_DETAIL_WORK_GUARD_HPP