rx-window_time_count.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_WINDOW_WITH_TIME_OR_COUNT_HPP)
#define RXCPP_OPERATORS_RX_WINDOW_WITH_TIME_OR_COUNT_HPP

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

namespace rxcpp {

namespace operators {

namespace detail {

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

template<class... AN>
struct window_with_time_or_count_invalid : public rxo::operator_base<window_with_time_or_count_invalid_arguments<AN...>> {
    using type = observable<window_with_time_or_count_invalid_arguments<AN...>, window_with_time_or_count_invalid<AN...>>;
};
template<class... AN>
using window_with_time_or_count_invalid_t = typename window_with_time_or_count_invalid<AN...>::type;

template<class T, class Duration, class Coordination>
struct window_with_time_or_count
{
    typedef rxu::decay_t<T> source_value_type;
    typedef observable<source_value_type> value_type;
    typedef rxu::decay_t<Coordination> coordination_type;
    typedef typename coordination_type::coordinator_type coordinator_type;
    typedef rxu::decay_t<Duration> duration_type;

    struct window_with_time_or_count_values
    {
        window_with_time_or_count_values(duration_type p, int n, coordination_type c)
            : period(p)
            , count(n)
            , coordination(c)
        {
        }
        duration_type period;
        int count;
        coordination_type coordination;
    };
    window_with_time_or_count_values initial;

    window_with_time_or_count(duration_type period, int count, coordination_type coordination)
        : initial(period, count, coordination)
    {
    }

    template<class Subscriber>
    struct window_with_time_or_count_observer
    {
        typedef window_with_time_or_count_observer<Subscriber> this_type;
        typedef rxu::decay_t<T> value_type;
        typedef rxu::decay_t<Subscriber> dest_type;
        typedef observer<T, this_type> observer_type;

        struct window_with_time_or_count_subscriber_values : public window_with_time_or_count_values
        {
            window_with_time_or_count_subscriber_values(composite_subscription cs, dest_type d, window_with_time_or_count_values v, coordinator_type c)
                : window_with_time_or_count_values(std::move(v))
                , cs(std::move(cs))
                , dest(std::move(d))
                , coordinator(std::move(c))
                , worker(coordinator.get_worker())
                , cursor(0)
                , subj_id(0)
            {
            }
            composite_subscription cs;
            dest_type dest;
            coordinator_type coordinator;
            rxsc::worker worker;
            mutable int cursor;
            mutable int subj_id;
            mutable rxcpp::subjects::subject<T> subj;
        };
        typedef std::shared_ptr<window_with_time_or_count_subscriber_values> state_type;
        state_type state;

        window_with_time_or_count_observer(composite_subscription cs, dest_type d, window_with_time_or_count_values v, coordinator_type c)
            : state(std::make_shared<window_with_time_or_count_subscriber_values>(window_with_time_or_count_subscriber_values(std::move(cs), std::move(d), std::move(v), std::move(c))))
        {
            auto new_id = state->subj_id;
            auto produce_time = state->worker.now();
            auto localState = state;

            auto disposer = [=](const rxsc::schedulable&){
                localState->cs.unsubscribe();
                localState->dest.unsubscribe();
                localState->worker.unsubscribe();
            };
            auto selectedDisposer = on_exception(
                [&](){return localState->coordinator.act(disposer);},
                localState->dest);
            if (selectedDisposer.empty()) {
                return;
            }

            localState->dest.add([=](){
                localState->worker.schedule(selectedDisposer.get());
            });
            localState->cs.add([=](){
                localState->worker.schedule(selectedDisposer.get());
            });

            //
            // The scheduler is FIFO for any time T. Since the observer is scheduling
            // on_next/on_error/oncompleted the timed schedule calls must be resheduled
            // when they occur to ensure that production happens after on_next/on_error/oncompleted
            //

            localState->worker.schedule(produce_time, [new_id, produce_time, localState](const rxsc::schedulable&){
                localState->worker.schedule(release_window(new_id, produce_time, localState));
            });
        }

        static std::function<void(const rxsc::schedulable&)> release_window(int id, rxsc::scheduler::clock_type::time_point expected, state_type state) {
            auto release = [id, expected, state](const rxsc::schedulable&) {
                if (id != state->subj_id)
                    return;

                state->subj.get_subscriber().on_completed();
                state->subj = rxcpp::subjects::subject<T>();
                state->dest.on_next(state->subj.get_observable().as_dynamic());
                state->cursor = 0;
                auto new_id = ++state->subj_id;
                auto produce_time = expected + state->period;
                state->worker.schedule(produce_time, [new_id, produce_time, state](const rxsc::schedulable&){
                    state->worker.schedule(release_window(new_id, produce_time, state));
                });
            };
            auto selectedRelease = on_exception(
                [&](){return state->coordinator.act(release);},
                state->dest);
            if (selectedRelease.empty()) {
                return std::function<void(const rxsc::schedulable&)>();
            }

            return std::function<void(const rxsc::schedulable&)>(selectedRelease.get());
        }

        void on_next(T v) const {
            auto localState = state;
            auto work = [v, localState](const rxsc::schedulable& self){
                localState->subj.get_subscriber().on_next(v);
                if (++localState->cursor == localState->count) {
                    release_window(localState->subj_id, localState->worker.now(), localState)(self);
                }
            };
            auto selectedWork = on_exception(
                [&](){return localState->coordinator.act(work);},
                localState->dest);
            if (selectedWork.empty()) {
                return;
            }
            localState->worker.schedule(selectedWork.get());
        }

        void on_error(std::exception_ptr e) const {
            auto localState = state;
            auto work = [e, localState](const rxsc::schedulable&){
                localState->subj.get_subscriber().on_error(e);
                localState->dest.on_error(e);
            };
            auto selectedWork = on_exception(
                [&](){return localState->coordinator.act(work);},
                localState->dest);
            if (selectedWork.empty()) {
                return;
            }
            localState->worker.schedule(selectedWork.get());
        }

        void on_completed() const {
            auto localState = state;
            auto work = [localState](const rxsc::schedulable&){
                localState->subj.get_subscriber().on_completed();
                localState->dest.on_completed();
            };
            auto selectedWork = on_exception(
                [&](){return localState->coordinator.act(work);},
                localState->dest);
            if (selectedWork.empty()) {
                return;
            }
            localState->worker.schedule(selectedWork.get());
        }

        static subscriber<T, observer_type> make(dest_type d, window_with_time_or_count_values v) {
            auto cs = composite_subscription();
            auto coordinator = v.coordination.create_coordinator();

            return make_subscriber<T>(cs, observer_type(this_type(cs, std::move(d), std::move(v), std::move(coordinator))));
        }
    };

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

}

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

}

template<>
struct member_overload<window_with_time_or_count_tag>
{
    template<class Observable, class Duration,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            std::is_convertible<Duration, rxsc::scheduler::clock_type::duration>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class WindowTimeCount = rxo::detail::window_with_time_or_count<SourceValue, rxu::decay_t<Duration>, identity_one_worker>,
        class Value = rxu::value_type_t<WindowTimeCount>>
    static auto member(Observable&& o, Duration&& period, int count)
        -> decltype(o.template lift<Value>(WindowTimeCount(std::forward<Duration>(period), count, identity_current_thread()))) {
        return      o.template lift<Value>(WindowTimeCount(std::forward<Duration>(period), count, identity_current_thread()));
    }

    template<class Observable, class Duration, class Coordination,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            std::is_convertible<Duration, rxsc::scheduler::clock_type::duration>,
            is_coordination<Coordination>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class WindowTimeCount = rxo::detail::window_with_time_or_count<SourceValue, rxu::decay_t<Duration>, rxu::decay_t<Coordination>>,
        class Value = rxu::value_type_t<WindowTimeCount>>
    static auto member(Observable&& o, Duration&& period, int count, Coordination&& cn)
        -> decltype(o.template lift<Value>(WindowTimeCount(std::forward<Duration>(period), count, std::forward<Coordination>(cn)))) {
        return      o.template lift<Value>(WindowTimeCount(std::forward<Duration>(period), count, std::forward<Coordination>(cn)));
    }

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

}

#endif