ready_future.hpp

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/*
    Copyright 2015 Adobe
    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 STLAB_CONCURRENCY_READY_FUTURE_HPP
#define STLAB_CONCURRENCY_READY_FUTURE_HPP

 
#include <stlab/config.hpp>
 
#include <exception>
#include <type_traits>
#include <utility>
 
#include <stlab/concurrency/future.hpp>
 
/**************************************************************************************************/
 
namespace stlab {
STLAB_VERSION_NAMESPACE_BEGIN()
 

 
/**************************************************************************************************/
 

template <typename T, typename E>
auto make_ready_future(T&& x, E executor) -> future<std::decay_t<T>> {
    auto p = package<std::decay_t<T>(std::decay_t<T>)>(
        std::move(executor), [](auto&& x) { return std::forward<decltype(x)>(x); });
    p.first(std::forward<T>(x));
    return std::move(p.second);
}

template <typename E>
auto make_ready_future(E executor) -> future<void> {
    auto p = package<void()>(std::move(executor), []() {});
    p.first();
    return p.second;
}
 
namespace detail {
 
template <class T>
struct _make_exceptional_future {
    template <typename E>
    auto operator()(const std::exception_ptr& error, E executor) const -> future<T> {
        auto p = package<T(T)>(std::move(executor),
                               [](auto&& a) { return std::forward<decltype(a)>(a); });
        p.first.set_exception(error);
        return std::move(p.second);
    }
};
 
template <>
struct _make_exceptional_future<void> {
    template <typename E>
    auto operator()(const std::exception_ptr& error, E executor) const -> future<void> {
        auto p = package<void()>(std::move(executor), []() {});
        p.first.set_exception(error);
        return std::move(p.second);
    }
};
 
} // namespace detail

template <typename T, typename E>
auto make_exceptional_future(const std::exception_ptr& error, E executor) -> future<T> {
    return detail::_make_exceptional_future<T>{}(error, std::move(executor));
}
 
/**************************************************************************************************/

 
STLAB_VERSION_NAMESPACE_END()
} // namespace stlab
 
/**************************************************************************************************/
 
#endif // STLAB_CONCURRENCY_READY_FUTURE_HPP