rx-sequence_equal.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_SEQUENCE_EQUAL_HPP)
#define RXCPP_OPERATORS_RX_SEQUENCE_EQUAL_HPP

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

namespace rxcpp {

namespace operators {

namespace detail {

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

template<class... AN>
struct sequence_equal_invalid : public rxo::operator_base<sequence_equal_invalid_arguments<AN...>> {
    using type = observable<sequence_equal_invalid_arguments<AN...>, sequence_equal_invalid<AN...>>;
};
template<class... AN>
using sequence_equal_invalid_t = typename sequence_equal_invalid<AN...>::type;

template<class T, class Observable, class OtherObservable, class BinaryPredicate, class Coordination>
struct sequence_equal : public operator_base<bool>
{
    typedef rxu::decay_t<Observable> source_type;
    typedef rxu::decay_t<T> source_value_type;
    typedef rxu::decay_t<OtherObservable> other_source_type;
    typedef typename other_source_type::value_type other_source_value_type;
    typedef rxu::decay_t<BinaryPredicate> predicate_type;
    typedef rxu::decay_t<Coordination> coordination_type;
    typedef typename coordination_type::coordinator_type coordinator_type;

    struct values {
        values(source_type s, other_source_type t, predicate_type pred, coordination_type sf)
                : source(std::move(s))
                , other(std::move(t))
                , pred(std::move(pred))
                , coordination(std::move(sf))
        {
        }

        source_type source;
        other_source_type other;
        predicate_type pred;
        coordination_type coordination;
    };

    values initial;

    sequence_equal(source_type s, other_source_type t, predicate_type pred, coordination_type sf)
        : initial(std::move(s), std::move(t), std::move(pred), std::move(sf))
    {
    }

    template<class Subscriber>
    void on_subscribe(Subscriber s) const {

        typedef Subscriber output_type;

        struct state_type
            : public std::enable_shared_from_this<state_type>
            , public values
        {
            state_type(const values& vals, coordinator_type coor, const output_type& o)
                : values(vals)
                , coordinator(std::move(coor))
                , out(o)
                , source_completed(false)
                , other_completed(false)
            {
                out.add(other_lifetime);
                out.add(source_lifetime);
            }

            composite_subscription other_lifetime;
            composite_subscription source_lifetime;
            coordinator_type coordinator;
            output_type out;
            
            mutable std::list<source_value_type> source_values;
            mutable std::list<other_source_value_type> other_values;
            mutable bool source_completed;
            mutable bool other_completed;
        };

        auto coordinator = initial.coordination.create_coordinator();
        auto state = std::make_shared<state_type>(initial, std::move(coordinator), std::move(s));

        auto other = on_exception(
            [&](){ return state->coordinator.in(state->other); },
            state->out);
        if (other.empty()) {
            return;
        }

        auto source = on_exception(
            [&](){ return state->coordinator.in(state->source); },
            state->out);
        if (source.empty()) {
            return;
        }

        auto check_equal = [state]() {
            if(!state->source_values.empty() && !state->other_values.empty()) {
                auto x = std::move(state->source_values.front());
                state->source_values.pop_front();

                auto y = std::move(state->other_values.front());
                state->other_values.pop_front();

                if (!state->pred(x, y)) {
                    state->out.on_next(false);
                    state->out.on_completed();
                }
            } else {
                if((!state->source_values.empty() && state->other_completed) ||
                   (!state->other_values.empty() && state->source_completed)) {
                    state->out.on_next(false);
                    state->out.on_completed();
                }
            }
        };
        
        auto check_complete = [state]() {
            if(state->source_completed && state->other_completed) {
                state->out.on_next(state->source_values.empty() && state->other_values.empty());
                state->out.on_completed();
            }
        };

        auto sinkOther = make_subscriber<other_source_value_type>(
            state->out,
            state->other_lifetime,
            // on_next
            [state, check_equal](other_source_value_type t) {
                auto& values = state->other_values;
                values.push_back(t);
                check_equal();
            },
            // on_error
            [state](std::exception_ptr e) {
                state->out.on_error(e);
            },
            // on_completed
            [state, check_complete]() {
                auto& completed = state->other_completed;
                completed = true;
                check_complete();
            }
        );

        auto selectedSinkOther = on_exception(
            [&](){ return state->coordinator.out(sinkOther); },
            state->out);
        if (selectedSinkOther.empty()) {
            return;
        }
        other->subscribe(std::move(selectedSinkOther.get()));

        source.get().subscribe(
            state->source_lifetime,
            // on_next
            [state, check_equal](source_value_type t) {
                auto& values = state->source_values;
                values.push_back(t);
                check_equal();
            },
            // on_error
            [state](std::exception_ptr e) {
                state->out.on_error(e);
            },
            // on_completed
            [state, check_complete]() {
                auto& completed = state->source_completed;
                completed = true;
                check_complete();
            }
        );        
    }
};

}

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

}

template<>
struct member_overload<sequence_equal_tag>
{
    template<class Observable, class OtherObservable,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            is_observable<OtherObservable>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class SequenceEqual = rxo::detail::sequence_equal<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<OtherObservable>, rxu::equal_to<>, identity_one_worker>,
        class Value = rxu::value_type_t<SequenceEqual>,
        class Result = observable<Value, SequenceEqual>>
    static Result member(Observable&& o, OtherObservable&& t) {
        return Result(SequenceEqual(std::forward<Observable>(o), std::forward<OtherObservable>(t), rxu::equal_to<>(), identity_current_thread()));
    }

    template<class Observable, class OtherObservable, class BinaryPredicate,
        class IsCoordination = is_coordination<BinaryPredicate>,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            is_observable<OtherObservable>,
            rxu::negation<IsCoordination>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class SequenceEqual = rxo::detail::sequence_equal<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<OtherObservable>, rxu::decay_t<BinaryPredicate>, identity_one_worker>,
        class Value = rxu::value_type_t<SequenceEqual>,
        class Result = observable<Value, SequenceEqual>>
    static Result member(Observable&& o, OtherObservable&& t, BinaryPredicate&& pred) {
        return Result(SequenceEqual(std::forward<Observable>(o), std::forward<OtherObservable>(t), std::forward<BinaryPredicate>(pred), identity_current_thread()));
    }

    template<class Observable, class OtherObservable, class Coordination,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            is_observable<OtherObservable>,
            is_coordination<Coordination>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class SequenceEqual = rxo::detail::sequence_equal<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<OtherObservable>, rxu::equal_to<>, rxu::decay_t<Coordination>>,
        class Value = rxu::value_type_t<SequenceEqual>,
        class Result = observable<Value, SequenceEqual>>
    static Result member(Observable&& o, OtherObservable&& t, Coordination&& cn) {
        return Result(SequenceEqual(std::forward<Observable>(o), std::forward<OtherObservable>(t), rxu::equal_to<>(), std::forward<Coordination>(cn)));
    }

    template<class Observable, class OtherObservable, class BinaryPredicate, class Coordination,
        class Enabled = rxu::enable_if_all_true_type_t<
            is_observable<Observable>,
            is_observable<OtherObservable>,
            is_coordination<Coordination>>,
        class SourceValue = rxu::value_type_t<Observable>,
        class SequenceEqual = rxo::detail::sequence_equal<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<OtherObservable>, rxu::decay_t<BinaryPredicate>, rxu::decay_t<Coordination>>,
        class Value = rxu::value_type_t<SequenceEqual>,
        class Result = observable<Value, SequenceEqual>>
    static Result member(Observable&& o, OtherObservable&& t, BinaryPredicate&& pred, Coordination&& cn) {
        return Result(SequenceEqual(std::forward<Observable>(o), std::forward<OtherObservable>(t), std::forward<BinaryPredicate>(pred), std::forward<Coordination>(cn)));
    }

    template<class... AN>
    static operators::detail::sequence_equal_invalid_t<AN...> member(const AN&...) {
        std::terminate();
        return {};
        static_assert(sizeof...(AN) == 10000, "sequence_equal takes (OtherObservable, optional BinaryPredicate, optional Coordination)");
    }
};

}

#endif