rx-timestamp.hpp

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// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.

#pragma once

#if !defined(RXCPP_OPERATORS_RX_TIMESTAMP_HPP)
#define RXCPP_OPERATORS_RX_TIMESTAMP_HPP

#include "../rx-includes.hpp"

namespace rxcpp {

namespace operators {

namespace detail {

template<class... AN>
struct timestamp_invalid_arguments {};

template<class... AN>
struct timestamp_invalid : public rxo::operator_base<timestamp_invalid_arguments<AN...>> {
    using type = observable<timestamp_invalid_arguments<AN...>, timestamp_invalid<AN...>>;
};
template<class... AN>
using timestamp_invalid_t = typename timestamp_invalid<AN...>::type;

template<class T, class Coordination>
struct timestamp
{
    typedef rxu::decay_t<T> source_value_type;
    typedef rxu::decay_t<Coordination> coordination_type;

    struct timestamp_values {
        timestamp_values(coordination_type c)
            : coordination(c)
        {
        }

        coordination_type coordination;
    };
    timestamp_values initial;

    timestamp(coordination_type coordination)
        : initial(coordination)
    {
    }

    template<class Subscriber>
    struct timestamp_observer
    {
        typedef timestamp_observer<Subscriber> this_type;
        typedef source_value_type value_type;
        typedef rxu::decay_t<Subscriber> dest_type;
        typedef observer<value_type, this_type> observer_type;
        dest_type dest;
        coordination_type coord;

        timestamp_observer(dest_type d, coordination_type coordination)
            : dest(std::move(d)),
              coord(std::move(coordination))
        {
        }

        void on_next(source_value_type v) const {
            dest.on_next(std::make_pair(v, coord.now()));
        }
        void on_error(std::exception_ptr e) const {
            dest.on_error(e);
        }
        void on_completed() const {
            dest.on_completed();
        }

        static subscriber<value_type, observer_type> make(dest_type d, timestamp_values v) {
            return make_subscriber<value_type>(d, this_type(d, v.coordination));
        }
    };

    template<class Subscriber>
    auto operator()(Subscriber dest) const
        -> decltype(timestamp_observer<Subscriber>::make(std::move(dest), initial)) {
        return      timestamp_observer<Subscriber>::make(std::move(dest), initial);
    }
};

}

template<class... AN>
auto timestamp(AN&&... an)
    ->      operator_factory<timestamp_tag, AN...> {
     return operator_factory<timestamp_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
}

}

template<>
struct member_overload<timestamp_tag>
{
    template<class Observable,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class Timestamp = rxo::detail::timestamp<SourceValue, identity_one_worker>,
        class Clock = typename rxsc::scheduler::clock_type::time_point,
        class Value = std::pair<SourceValue, Clock>>
    static auto member(Observable&& o)
        -> decltype(o.template lift<Value>(Timestamp(identity_current_thread()))) {
        return      o.template lift<Value>(Timestamp(identity_current_thread()));
    }

    template<class Observable, class Coordination,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            is_coordination<Coordination>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class Timestamp = rxo::detail::timestamp<SourceValue, rxu::decay_t<Coordination>>,
        class Clock = typename rxsc::scheduler::clock_type::time_point,
        class Value = std::pair<SourceValue, Clock>>
    static auto member(Observable&& o, Coordination&& cn)
        -> decltype(o.template lift<Value>(Timestamp(std::forward<Coordination>(cn)))) {
        return      o.template lift<Value>(Timestamp(std::forward<Coordination>(cn)));
    }

    template<class... AN>
    static operators::detail::timestamp_invalid_t<AN...> member(AN...) {
        std::terminate();
        return {};
        static_assert(sizeof...(AN) == 10000, "timestamp takes (optional Coordination)");
    }
};

}

#endif