asyncpp/include/asyncpp/core/future/and_then.inl

#pragma once

#include "map.h"

namespace asyncpp {
namespace __future {

    /* and_then_impl */

    template<
        typename T_future,
        typename T_lambda>
    template<
        typename X_future,
        typename X_lambda>
    and_then_impl<T_future, T_lambda>
        ::and_then_impl(
            X_future&& p_first,
            X_lambda&& p_lambda)
        : first (std::forward<X_future>(p_first))
        , lambda(std::forward<X_lambda>(p_lambda))
        { }

    template<
        typename T_future,
        typename T_lambda>
    typename and_then_impl<T_future, T_lambda>::result_type
    and_then_impl<T_future, T_lambda>
        ::poll()
    {
        while (true)
        {
            if (second)
            {
                return second->poll();
            }
            else
            {
                auto r = first.poll();
                if (!r)
                    return result_type::not_ready();

                second = std::make_unique<second_future_type>(r.call(lambda));
            }
        }
    }

} }