403 lines
19 KiB
C++
403 lines
19 KiB
C++
// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
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#pragma once
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/*! \file rx-group_by.hpp
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\brief Return an observable that emits grouped_observables, each of which corresponds to a unique key value and each of which emits those items from the source observable that share that key value.
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\tparam KeySelector the type of the key extracting function
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\tparam MarbleSelector the type of the element extracting function
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\tparam BinaryPredicate the type of the key comparing function
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\tparam DurationSelector the type of the duration observable function
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\param ks a function that extracts the key for each item (optional)
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\param ms a function that extracts the return element for each item (optional)
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\param p a function that implements comparison of two keys (optional)
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\return Observable that emits values of grouped_observable type, each of which corresponds to a unique key value and each of which emits those items from the source observable that share that key value.
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\sample
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\snippet group_by.cpp group_by full intro
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\snippet group_by.cpp group_by full sample
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\snippet output.txt group_by full sample
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\sample
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\snippet group_by.cpp group_by sample
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\snippet output.txt group_by sample
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*/
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#if !defined(RXCPP_OPERATORS_RX_GROUP_BY_HPP)
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#define RXCPP_OPERATORS_RX_GROUP_BY_HPP
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#include "../rx-includes.hpp"
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namespace rxcpp {
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namespace operators {
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namespace detail {
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template<class... AN>
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struct group_by_invalid_arguments {};
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template<class... AN>
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struct group_by_invalid : public rxo::operator_base<group_by_invalid_arguments<AN...>> {
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using type = observable<group_by_invalid_arguments<AN...>, group_by_invalid<AN...>>;
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};
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template<class... AN>
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using group_by_invalid_t = typename group_by_invalid<AN...>::type;
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template<class T, class Selector>
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struct is_group_by_selector_for {
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typedef rxu::decay_t<Selector> selector_type;
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typedef T source_value_type;
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struct tag_not_valid {};
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template<class CV, class CS>
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static auto check(int) -> decltype((*(CS*)nullptr)(*(CV*)nullptr));
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template<class CV, class CS>
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static tag_not_valid check(...);
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typedef decltype(check<source_value_type, selector_type>(0)) type;
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static const bool value = !std::is_same<type, tag_not_valid>::value;
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};
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template<class T, class Observable, class KeySelector, class MarbleSelector, class BinaryPredicate, class DurationSelector>
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struct group_by_traits
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{
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typedef T source_value_type;
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typedef rxu::decay_t<Observable> source_type;
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typedef rxu::decay_t<KeySelector> key_selector_type;
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typedef rxu::decay_t<MarbleSelector> marble_selector_type;
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typedef rxu::decay_t<BinaryPredicate> predicate_type;
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typedef rxu::decay_t<DurationSelector> duration_selector_type;
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static_assert(is_group_by_selector_for<source_value_type, key_selector_type>::value, "group_by KeySelector must be a function with the signature key_type(source_value_type)");
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typedef typename is_group_by_selector_for<source_value_type, key_selector_type>::type key_type;
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static_assert(is_group_by_selector_for<source_value_type, marble_selector_type>::value, "group_by MarbleSelector must be a function with the signature marble_type(source_value_type)");
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typedef typename is_group_by_selector_for<source_value_type, marble_selector_type>::type marble_type;
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typedef rxsub::subject<marble_type> subject_type;
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typedef std::map<key_type, typename subject_type::subscriber_type, predicate_type> key_subscriber_map_type;
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typedef grouped_observable<key_type, marble_type> grouped_observable_type;
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};
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template<class T, class Observable, class KeySelector, class MarbleSelector, class BinaryPredicate, class DurationSelector>
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struct group_by
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{
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typedef group_by_traits<T, Observable, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector> traits_type;
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typedef typename traits_type::key_selector_type key_selector_type;
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typedef typename traits_type::marble_selector_type marble_selector_type;
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typedef typename traits_type::marble_type marble_type;
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typedef typename traits_type::predicate_type predicate_type;
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typedef typename traits_type::duration_selector_type duration_selector_type;
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typedef typename traits_type::subject_type subject_type;
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typedef typename traits_type::key_type key_type;
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typedef typename traits_type::key_subscriber_map_type group_map_type;
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typedef std::vector<typename composite_subscription::weak_subscription> bindings_type;
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struct group_by_state_type
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{
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group_by_state_type(composite_subscription sl, predicate_type p)
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: source_lifetime(sl)
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, groups(p)
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, observers(0)
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{}
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composite_subscription source_lifetime;
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rxsc::worker worker;
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group_map_type groups;
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std::atomic<int> observers;
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};
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template<class Subscriber>
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static void stopsource(Subscriber&& dest, std::shared_ptr<group_by_state_type>& state) {
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++state->observers;
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dest.add([state](){
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if (!state->source_lifetime.is_subscribed()) {
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return;
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}
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--state->observers;
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if (state->observers == 0) {
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state->source_lifetime.unsubscribe();
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}
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});
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}
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struct group_by_values
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{
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group_by_values(key_selector_type ks, marble_selector_type ms, predicate_type p, duration_selector_type ds)
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: keySelector(std::move(ks))
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, marbleSelector(std::move(ms))
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, predicate(std::move(p))
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, durationSelector(std::move(ds))
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{
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}
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mutable key_selector_type keySelector;
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mutable marble_selector_type marbleSelector;
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mutable predicate_type predicate;
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mutable duration_selector_type durationSelector;
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};
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group_by_values initial;
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group_by(key_selector_type ks, marble_selector_type ms, predicate_type p, duration_selector_type ds)
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: initial(std::move(ks), std::move(ms), std::move(p), std::move(ds))
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{
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}
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struct group_by_observable : public rxs::source_base<marble_type>
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{
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mutable std::shared_ptr<group_by_state_type> state;
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subject_type subject;
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key_type key;
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group_by_observable(std::shared_ptr<group_by_state_type> st, subject_type s, key_type k)
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: state(std::move(st))
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, subject(std::move(s))
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, key(k)
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{
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}
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template<class Subscriber>
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void on_subscribe(Subscriber&& o) const {
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group_by::stopsource(o, state);
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subject.get_observable().subscribe(std::forward<Subscriber>(o));
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}
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key_type on_get_key() {
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return key;
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}
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};
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template<class Subscriber>
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struct group_by_observer : public group_by_values
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{
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typedef group_by_observer<Subscriber> this_type;
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typedef typename traits_type::grouped_observable_type value_type;
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typedef rxu::decay_t<Subscriber> dest_type;
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typedef observer<T, this_type> observer_type;
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dest_type dest;
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mutable std::shared_ptr<group_by_state_type> state;
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group_by_observer(composite_subscription l, dest_type d, group_by_values v)
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: group_by_values(v)
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, dest(std::move(d))
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, state(std::make_shared<group_by_state_type>(l, group_by_values::predicate))
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{
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group_by::stopsource(dest, state);
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}
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void on_next(T v) const {
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auto selectedKey = on_exception(
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[&](){
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return this->keySelector(v);},
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[this](rxu::error_ptr e){on_error(e);});
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if (selectedKey.empty()) {
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return;
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}
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auto g = state->groups.find(selectedKey.get());
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if (g == state->groups.end()) {
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if (!dest.is_subscribed()) {
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return;
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}
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auto sub = subject_type();
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g = state->groups.insert(std::make_pair(selectedKey.get(), sub.get_subscriber())).first;
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auto obs = make_dynamic_grouped_observable<key_type, marble_type>(group_by_observable(state, sub, selectedKey.get()));
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auto durationObs = on_exception(
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[&](){
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return this->durationSelector(obs);},
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[this](rxu::error_ptr e){on_error(e);});
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if (durationObs.empty()) {
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return;
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}
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dest.on_next(obs);
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composite_subscription duration_sub;
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auto ssub = state->source_lifetime.add(duration_sub);
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auto expire_state = state;
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auto expire_dest = g->second;
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auto expire = [=]() {
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auto g = expire_state->groups.find(selectedKey.get());
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if (g != expire_state->groups.end()) {
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expire_state->groups.erase(g);
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expire_dest.on_completed();
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}
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expire_state->source_lifetime.remove(ssub);
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};
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auto robs = durationObs.get().take(1);
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duration_sub.add(robs.subscribe(
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[](const typename decltype(robs)::value_type &){},
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[=](rxu::error_ptr) {expire();},
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[=](){expire();}
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));
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}
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auto selectedMarble = on_exception(
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[&](){
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return this->marbleSelector(v);},
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[this](rxu::error_ptr e){on_error(e);});
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if (selectedMarble.empty()) {
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return;
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}
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g->second.on_next(std::move(selectedMarble.get()));
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}
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void on_error(rxu::error_ptr e) const {
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for(auto& g : state->groups) {
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g.second.on_error(e);
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}
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dest.on_error(e);
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}
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void on_completed() const {
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for(auto& g : state->groups) {
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g.second.on_completed();
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}
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dest.on_completed();
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}
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static subscriber<T, observer_type> make(dest_type d, group_by_values v) {
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auto cs = composite_subscription();
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return make_subscriber<T>(cs, observer_type(this_type(cs, std::move(d), std::move(v))));
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}
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};
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template<class Subscriber>
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auto operator()(Subscriber dest) const
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-> decltype(group_by_observer<Subscriber>::make(std::move(dest), initial)) {
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return group_by_observer<Subscriber>::make(std::move(dest), initial);
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}
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};
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template<class KeySelector, class MarbleSelector, class BinaryPredicate, class DurationSelector>
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class group_by_factory
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{
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typedef rxu::decay_t<KeySelector> key_selector_type;
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typedef rxu::decay_t<MarbleSelector> marble_selector_type;
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typedef rxu::decay_t<BinaryPredicate> predicate_type;
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typedef rxu::decay_t<DurationSelector> duration_selector_type;
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key_selector_type keySelector;
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marble_selector_type marbleSelector;
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predicate_type predicate;
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duration_selector_type durationSelector;
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public:
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group_by_factory(key_selector_type ks, marble_selector_type ms, predicate_type p, duration_selector_type ds)
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: keySelector(std::move(ks))
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, marbleSelector(std::move(ms))
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, predicate(std::move(p))
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, durationSelector(std::move(ds))
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{
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}
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template<class Observable>
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struct group_by_factory_traits
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{
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typedef rxu::value_type_t<rxu::decay_t<Observable>> value_type;
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typedef detail::group_by_traits<value_type, Observable, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector> traits_type;
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typedef detail::group_by<value_type, Observable, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector> group_by_type;
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};
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template<class Observable>
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auto operator()(Observable&& source)
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-> decltype(source.template lift<typename group_by_factory_traits<Observable>::traits_type::grouped_observable_type>(typename group_by_factory_traits<Observable>::group_by_type(std::move(keySelector), std::move(marbleSelector), std::move(predicate), std::move(durationSelector)))) {
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return source.template lift<typename group_by_factory_traits<Observable>::traits_type::grouped_observable_type>(typename group_by_factory_traits<Observable>::group_by_type(std::move(keySelector), std::move(marbleSelector), std::move(predicate), std::move(durationSelector)));
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}
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};
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}
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/*! @copydoc rx-group_by.hpp
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*/
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template<class... AN>
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auto group_by(AN&&... an)
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-> operator_factory<group_by_tag, AN...> {
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return operator_factory<group_by_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
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}
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}
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template<>
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struct member_overload<group_by_tag>
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{
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template<class Observable, class KeySelector, class MarbleSelector, class BinaryPredicate, class DurationSelector,
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class SourceValue = rxu::value_type_t<Observable>,
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class Traits = rxo::detail::group_by_traits<SourceValue, rxu::decay_t<Observable>, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector>,
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class GroupBy = rxo::detail::group_by<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<KeySelector>, rxu::decay_t<MarbleSelector>, rxu::decay_t<BinaryPredicate>, rxu::decay_t<DurationSelector>>,
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class Value = typename Traits::grouped_observable_type>
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static auto member(Observable&& o, KeySelector&& ks, MarbleSelector&& ms, BinaryPredicate&& p, DurationSelector&& ds)
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-> decltype(o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), std::forward<MarbleSelector>(ms), std::forward<BinaryPredicate>(p), std::forward<DurationSelector>(ds)))) {
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return o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), std::forward<MarbleSelector>(ms), std::forward<BinaryPredicate>(p), std::forward<DurationSelector>(ds)));
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}
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template<class Observable, class KeySelector, class MarbleSelector, class BinaryPredicate,
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class DurationSelector=rxu::ret<observable<int, rxs::detail::never<int>>>,
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class SourceValue = rxu::value_type_t<Observable>,
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class Traits = rxo::detail::group_by_traits<SourceValue, rxu::decay_t<Observable>, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector>,
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class GroupBy = rxo::detail::group_by<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<KeySelector>, rxu::decay_t<MarbleSelector>, rxu::decay_t<BinaryPredicate>, rxu::decay_t<DurationSelector>>,
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class Value = typename Traits::grouped_observable_type>
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static auto member(Observable&& o, KeySelector&& ks, MarbleSelector&& ms, BinaryPredicate&& p)
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-> decltype(o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), std::forward<MarbleSelector>(ms), std::forward<BinaryPredicate>(p), rxu::ret<observable<int, rxs::detail::never<int>>>()))) {
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return o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), std::forward<MarbleSelector>(ms), std::forward<BinaryPredicate>(p), rxu::ret<observable<int, rxs::detail::never<int>>>()));
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}
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template<class Observable, class KeySelector, class MarbleSelector,
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class BinaryPredicate=rxu::less,
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class DurationSelector=rxu::ret<observable<int, rxs::detail::never<int>>>,
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class SourceValue = rxu::value_type_t<Observable>,
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class Traits = rxo::detail::group_by_traits<SourceValue, rxu::decay_t<Observable>, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector>,
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class GroupBy = rxo::detail::group_by<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<KeySelector>, rxu::decay_t<MarbleSelector>, rxu::decay_t<BinaryPredicate>, rxu::decay_t<DurationSelector>>,
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class Value = typename Traits::grouped_observable_type>
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static auto member(Observable&& o, KeySelector&& ks, MarbleSelector&& ms)
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-> decltype(o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), std::forward<MarbleSelector>(ms), rxu::less(), rxu::ret<observable<int, rxs::detail::never<int>>>()))) {
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return o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), std::forward<MarbleSelector>(ms), rxu::less(), rxu::ret<observable<int, rxs::detail::never<int>>>()));
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}
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template<class Observable, class KeySelector,
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class MarbleSelector=rxu::detail::take_at<0>,
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class BinaryPredicate=rxu::less,
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class DurationSelector=rxu::ret<observable<int, rxs::detail::never<int>>>,
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class SourceValue = rxu::value_type_t<Observable>,
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class Traits = rxo::detail::group_by_traits<SourceValue, rxu::decay_t<Observable>, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector>,
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class GroupBy = rxo::detail::group_by<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<KeySelector>, rxu::decay_t<MarbleSelector>, rxu::decay_t<BinaryPredicate>, rxu::decay_t<DurationSelector>>,
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class Value = typename Traits::grouped_observable_type>
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static auto member(Observable&& o, KeySelector&& ks)
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-> decltype(o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), rxu::detail::take_at<0>(), rxu::less(), rxu::ret<observable<int, rxs::detail::never<int>>>()))) {
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return o.template lift<Value>(GroupBy(std::forward<KeySelector>(ks), rxu::detail::take_at<0>(), rxu::less(), rxu::ret<observable<int, rxs::detail::never<int>>>()));
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}
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template<class Observable,
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class KeySelector=rxu::detail::take_at<0>,
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class MarbleSelector=rxu::detail::take_at<0>,
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class BinaryPredicate=rxu::less,
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class DurationSelector=rxu::ret<observable<int, rxs::detail::never<int>>>,
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class Enabled = rxu::enable_if_all_true_type_t<
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all_observables<Observable>>,
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class SourceValue = rxu::value_type_t<Observable>,
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class Traits = rxo::detail::group_by_traits<SourceValue, rxu::decay_t<Observable>, KeySelector, MarbleSelector, BinaryPredicate, DurationSelector>,
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class GroupBy = rxo::detail::group_by<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<KeySelector>, rxu::decay_t<MarbleSelector>, rxu::decay_t<BinaryPredicate>, rxu::decay_t<DurationSelector>>,
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class Value = typename Traits::grouped_observable_type>
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static auto member(Observable&& o)
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-> decltype(o.template lift<Value>(GroupBy(rxu::detail::take_at<0>(), rxu::detail::take_at<0>(), rxu::less(), rxu::ret<observable<int, rxs::detail::never<int>>>()))) {
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return o.template lift<Value>(GroupBy(rxu::detail::take_at<0>(), rxu::detail::take_at<0>(), rxu::less(), rxu::ret<observable<int, rxs::detail::never<int>>>()));
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}
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template<class... AN>
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static operators::detail::group_by_invalid_t<AN...> member(const AN&...) {
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std::terminate();
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return {};
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static_assert(sizeof...(AN) == 10000, "group_by takes (optional KeySelector, optional MarbleSelector, optional BinaryKeyPredicate, optional DurationSelector), KeySelector takes (Observable::value_type) -> KeyValue, MarbleSelector takes (Observable::value_type) -> MarbleValue, BinaryKeyPredicate takes (KeyValue, KeyValue) -> bool, DurationSelector takes (Observable::value_type) -> Observable");
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}
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};
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}
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#endif
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