341 lines
15 KiB
C++
341 lines
15 KiB
C++
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// 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-flat_map.hpp
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\brief For each item from this observable use the CollectionSelector to produce an observable and subscribe to that observable.
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For each item from all of the produced observables use the ResultSelector to produce a value to emit from the new observable that is returned.
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\tparam CollectionSelector the type of the observable producing function. CollectionSelector must be a function with the signature observable(flat_map::source_value_type)
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\tparam ResultSelector the type of the aggregation function (optional). ResultSelector must be a function with the signature flat_map::value_type(flat_map::source_value_type, flat_map::collection_value_type).
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\tparam Coordination the type of the scheduler (optional).
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\param s a function that returns an observable for each item emitted by the source observable.
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\param rs a function that combines one item emitted by each of the source and collection observables and returns an item to be emitted by the resulting observable (optional).
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\param cn the scheduler to synchronize sources from different contexts (optional).
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\return Observable that emits the results of applying a function to a pair of values emitted by the source observable and the collection observable.
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Observables, produced by the CollectionSelector, are merged. There is another operator rxcpp::observable<T,SourceType>::flat_map that works similar but concatenates the observables.
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\sample
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\snippet flat_map.cpp flat_map sample
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\snippet output.txt flat_map sample
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\sample
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\snippet flat_map.cpp threaded flat_map sample
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\snippet output.txt threaded flat_map sample
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*/
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#if !defined(RXCPP_OPERATORS_RX_FLATMAP_HPP)
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#define RXCPP_OPERATORS_RX_FLATMAP_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 flat_map_invalid_arguments {};
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template<class... AN>
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struct flat_map_invalid : public rxo::operator_base<flat_map_invalid_arguments<AN...>> {
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using type = observable<flat_map_invalid_arguments<AN...>, flat_map_invalid<AN...>>;
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};
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template<class... AN>
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using flat_map_invalid_t = typename flat_map_invalid<AN...>::type;
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template<class Observable, class CollectionSelector, class ResultSelector, class Coordination>
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struct flat_map_traits {
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typedef rxu::decay_t<Observable> source_type;
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typedef rxu::decay_t<CollectionSelector> collection_selector_type;
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typedef rxu::decay_t<ResultSelector> result_selector_type;
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typedef rxu::decay_t<Coordination> coordination_type;
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typedef typename source_type::value_type source_value_type;
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struct tag_not_valid {};
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template<class CV, class CCS>
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static auto collection_check(int) -> decltype((*(CCS*)nullptr)(*(CV*)nullptr));
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template<class CV, class CCS>
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static tag_not_valid collection_check(...);
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static_assert(!std::is_same<decltype(collection_check<source_value_type, collection_selector_type>(0)), tag_not_valid>::value, "flat_map CollectionSelector must be a function with the signature observable(flat_map::source_value_type)");
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typedef rxu::decay_t<decltype((*(collection_selector_type*)nullptr)((*(source_value_type*)nullptr)))> collection_type;
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static_assert(is_observable<collection_type>::value, "flat_map CollectionSelector must return an observable");
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typedef typename collection_type::value_type collection_value_type;
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template<class CV, class CCV, class CRS>
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static auto result_check(int) -> decltype((*(CRS*)nullptr)(*(CV*)nullptr, *(CCV*)nullptr));
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template<class CV, class CCV, class CRS>
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static tag_not_valid result_check(...);
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static_assert(!std::is_same<decltype(result_check<source_value_type, collection_value_type, result_selector_type>(0)), tag_not_valid>::value, "flat_map ResultSelector must be a function with the signature flat_map::value_type(flat_map::source_value_type, flat_map::collection_value_type)");
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typedef rxu::decay_t<decltype((*(result_selector_type*)nullptr)(*(source_value_type*)nullptr, *(collection_value_type*)nullptr))> value_type;
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};
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template<class Observable, class CollectionSelector, class ResultSelector, class Coordination>
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struct flat_map
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: public operator_base<rxu::value_type_t<flat_map_traits<Observable, CollectionSelector, ResultSelector, Coordination>>>
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{
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typedef flat_map<Observable, CollectionSelector, ResultSelector, Coordination> this_type;
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typedef flat_map_traits<Observable, CollectionSelector, ResultSelector, Coordination> traits;
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typedef typename traits::source_type source_type;
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typedef typename traits::collection_selector_type collection_selector_type;
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typedef typename traits::result_selector_type result_selector_type;
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typedef typename traits::source_value_type source_value_type;
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typedef typename traits::collection_type collection_type;
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typedef typename traits::collection_value_type collection_value_type;
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typedef typename traits::coordination_type coordination_type;
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typedef typename coordination_type::coordinator_type coordinator_type;
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struct values
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{
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values(source_type o, collection_selector_type s, result_selector_type rs, coordination_type sf)
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: source(std::move(o))
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, selectCollection(std::move(s))
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, selectResult(std::move(rs))
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, coordination(std::move(sf))
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{
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}
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source_type source;
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collection_selector_type selectCollection;
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result_selector_type selectResult;
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coordination_type coordination;
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};
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values initial;
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flat_map(source_type o, collection_selector_type s, result_selector_type rs, coordination_type sf)
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: initial(std::move(o), std::move(s), std::move(rs), std::move(sf))
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{
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}
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template<class Subscriber>
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void on_subscribe(Subscriber scbr) const {
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static_assert(is_subscriber<Subscriber>::value, "subscribe must be passed a subscriber");
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typedef Subscriber output_type;
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struct state_type
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: public std::enable_shared_from_this<state_type>
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, public values
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{
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state_type(values i, coordinator_type coor, output_type oarg)
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: values(std::move(i))
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, pendingCompletions(0)
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, coordinator(std::move(coor))
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, out(std::move(oarg))
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{
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}
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// on_completed on the output must wait until all the
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// subscriptions have received on_completed
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int pendingCompletions;
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coordinator_type coordinator;
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output_type out;
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};
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auto coordinator = initial.coordination.create_coordinator(scbr.get_subscription());
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// take a copy of the values for each subscription
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auto state = std::make_shared<state_type>(initial, std::move(coordinator), std::move(scbr));
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composite_subscription outercs;
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// when the out observer is unsubscribed all the
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// inner subscriptions are unsubscribed as well
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state->out.add(outercs);
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auto source = on_exception(
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[&](){return state->coordinator.in(state->source);},
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state->out);
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if (source.empty()) {
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return;
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}
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++state->pendingCompletions;
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// this subscribe does not share the observer subscription
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// so that when it is unsubscribed the observer can be called
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// until the inner subscriptions have finished
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auto sink = make_subscriber<source_value_type>(
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state->out,
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outercs,
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// on_next
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[state](source_value_type st) {
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composite_subscription innercs;
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// when the out observer is unsubscribed all the
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// inner subscriptions are unsubscribed as well
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auto innercstoken = state->out.add(innercs);
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innercs.add(make_subscription([state, innercstoken](){
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state->out.remove(innercstoken);
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}));
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auto selectedCollection = state->selectCollection(st);
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auto selectedSource = state->coordinator.in(selectedCollection);
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++state->pendingCompletions;
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// this subscribe does not share the source subscription
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// so that when it is unsubscribed the source will continue
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auto sinkInner = make_subscriber<collection_value_type>(
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state->out,
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innercs,
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// on_next
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[state, st](collection_value_type ct) {
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auto selectedResult = state->selectResult(st, std::move(ct));
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state->out.on_next(std::move(selectedResult));
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},
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// on_error
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[state](rxu::error_ptr e) {
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state->out.on_error(e);
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},
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//on_completed
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[state](){
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if (--state->pendingCompletions == 0) {
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state->out.on_completed();
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}
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}
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);
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auto selectedSinkInner = state->coordinator.out(sinkInner);
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selectedSource.subscribe(std::move(selectedSinkInner));
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},
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// on_error
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[state](rxu::error_ptr e) {
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state->out.on_error(e);
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},
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// on_completed
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[state]() {
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if (--state->pendingCompletions == 0) {
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state->out.on_completed();
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}
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}
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);
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auto selectedSink = on_exception(
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[&](){return state->coordinator.out(sink);},
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state->out);
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if (selectedSink.empty()) {
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return;
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}
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source->subscribe(std::move(selectedSink.get()));
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}
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};
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}
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/*! @copydoc rx-flat_map.hpp
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*/
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template<class... AN>
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auto flat_map(AN&&... an)
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-> operator_factory<flat_map_tag, AN...> {
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return operator_factory<flat_map_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
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}
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/*! @copydoc rx-flat_map.hpp
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*/
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template<class... AN>
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auto merge_transform(AN&&... an)
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-> operator_factory<flat_map_tag, AN...> {
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return operator_factory<flat_map_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<flat_map_tag>
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{
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template<class Observable, class CollectionSelector,
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class CollectionSelectorType = rxu::decay_t<CollectionSelector>,
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class SourceValue = rxu::value_type_t<Observable>,
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class CollectionType = rxu::result_of_t<CollectionSelectorType(SourceValue)>,
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class ResultSelectorType = rxu::detail::take_at<1>,
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class Enabled = rxu::enable_if_all_true_type_t<
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all_observables<Observable, CollectionType>>,
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class FlatMap = rxo::detail::flat_map<rxu::decay_t<Observable>, rxu::decay_t<CollectionSelector>, ResultSelectorType, identity_one_worker>,
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class CollectionValueType = rxu::value_type_t<CollectionType>,
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class Value = rxu::result_of_t<ResultSelectorType(SourceValue, CollectionValueType)>,
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class Result = observable<Value, FlatMap>
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>
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static Result member(Observable&& o, CollectionSelector&& s) {
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return Result(FlatMap(std::forward<Observable>(o), std::forward<CollectionSelector>(s), ResultSelectorType(), identity_current_thread()));
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}
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template<class Observable, class CollectionSelector, class Coordination,
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class CollectionSelectorType = rxu::decay_t<CollectionSelector>,
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class SourceValue = rxu::value_type_t<Observable>,
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class CollectionType = rxu::result_of_t<CollectionSelectorType(SourceValue)>,
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class ResultSelectorType = rxu::detail::take_at<1>,
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class Enabled = rxu::enable_if_all_true_type_t<
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all_observables<Observable, CollectionType>,
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is_coordination<Coordination>>,
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class FlatMap = rxo::detail::flat_map<rxu::decay_t<Observable>, rxu::decay_t<CollectionSelector>, ResultSelectorType, rxu::decay_t<Coordination>>,
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class CollectionValueType = rxu::value_type_t<CollectionType>,
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class Value = rxu::result_of_t<ResultSelectorType(SourceValue, CollectionValueType)>,
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class Result = observable<Value, FlatMap>
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>
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static Result member(Observable&& o, CollectionSelector&& s, Coordination&& cn) {
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return Result(FlatMap(std::forward<Observable>(o), std::forward<CollectionSelector>(s), ResultSelectorType(), std::forward<Coordination>(cn)));
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}
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template<class Observable, class CollectionSelector, class ResultSelector,
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class IsCoordination = is_coordination<ResultSelector>,
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class CollectionSelectorType = rxu::decay_t<CollectionSelector>,
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class SourceValue = rxu::value_type_t<Observable>,
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class CollectionType = rxu::result_of_t<CollectionSelectorType(SourceValue)>,
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class Enabled = rxu::enable_if_all_true_type_t<
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all_observables<Observable, CollectionType>,
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rxu::negation<IsCoordination>>,
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class FlatMap = rxo::detail::flat_map<rxu::decay_t<Observable>, rxu::decay_t<CollectionSelector>, rxu::decay_t<ResultSelector>, identity_one_worker>,
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class CollectionValueType = rxu::value_type_t<CollectionType>,
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class ResultSelectorType = rxu::decay_t<ResultSelector>,
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class Value = rxu::result_of_t<ResultSelectorType(SourceValue, CollectionValueType)>,
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class Result = observable<Value, FlatMap>
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>
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static Result member(Observable&& o, CollectionSelector&& s, ResultSelector&& rs) {
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return Result(FlatMap(std::forward<Observable>(o), std::forward<CollectionSelector>(s), std::forward<ResultSelector>(rs), identity_current_thread()));
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}
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template<class Observable, class CollectionSelector, class ResultSelector, class Coordination,
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class CollectionSelectorType = rxu::decay_t<CollectionSelector>,
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class SourceValue = rxu::value_type_t<Observable>,
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class CollectionType = rxu::result_of_t<CollectionSelectorType(SourceValue)>,
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class Enabled = rxu::enable_if_all_true_type_t<
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all_observables<Observable, CollectionType>,
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is_coordination<Coordination>>,
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class FlatMap = rxo::detail::flat_map<rxu::decay_t<Observable>, rxu::decay_t<CollectionSelector>, rxu::decay_t<ResultSelector>, rxu::decay_t<Coordination>>,
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class CollectionValueType = rxu::value_type_t<CollectionType>,
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class ResultSelectorType = rxu::decay_t<ResultSelector>,
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class Value = rxu::result_of_t<ResultSelectorType(SourceValue, CollectionValueType)>,
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class Result = observable<Value, FlatMap>
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>
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static Result member(Observable&& o, CollectionSelector&& s, ResultSelector&& rs, Coordination&& cn) {
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return Result(FlatMap(std::forward<Observable>(o), std::forward<CollectionSelector>(s), std::forward<ResultSelector>(rs), std::forward<Coordination>(cn)));
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}
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template<class... AN>
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static operators::detail::flat_map_invalid_t<AN...> member(AN...) {
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std::terminate();
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return {};
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static_assert(sizeof...(AN) == 10000, "flat_map takes (CollectionSelector, optional ResultSelector, optional Coordination)");
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}
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};
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||
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}
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||
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||
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#endif
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