get_forward_progress_guarantee.h

Go to the documentation of this file.

#include "di/execution/concepts/scheduler.h"
#include "di/function/tag_invoke.h"
 
namespace di::execution {
enum class ForwardProgressGuarantee {
    Concurrent,
    Parallel,
    WeaklyParallel,
};
 
namespace detail {
    struct GetForwardProgressGuaranteeFunction {
        template<concepts::Scheduler Sched>
        constexpr auto operator()(Sched&& scheduler) const -> ForwardProgressGuarantee {
            if constexpr (concepts::TagInvocable<GetForwardProgressGuaranteeFunction, Sched const&>) {
                static_assert(
                    concepts::SameAs<ForwardProgressGuarantee,
                                     meta::TagInvokeResult<GetForwardProgressGuaranteeFunction, Sched const&>>,
                    "Customizations of get_forward_progress_guarantee() must return di::ForwardProgressGuarantee.");
                return function::tag_invoke(*this, util::as_const(scheduler));
            } else {
                return ForwardProgressGuarantee::WeaklyParallel;
            }
        }
    };
}
 
constexpr inline auto get_forward_progress_guarantee = detail::GetForwardProgressGuaranteeFunction {};
}