feat add rxcpp
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tqcq
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3party/rxcpp/operators/rx-ref_count.hpp
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3party/rxcpp/operators/rx-ref_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.
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#pragma once
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/*! \file rx-ref_count.hpp
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\brief Make some \c connectable_observable behave like an ordinary \c observable.
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Uses a reference count of the subscribers to control the connection to the published observable.
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The first subscription will cause a call to \c connect(), and the last \c unsubscribe will unsubscribe the connection.
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There are 2 variants of the operator:
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\li \c ref_count(): calls \c connect on the \c source \c connectable_observable.
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\li \c ref_count(other): calls \c connect on the \c other \c connectable_observable.
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\tparam ConnectableObservable the type of the \c other \c connectable_observable (optional)
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\param other \c connectable_observable to call \c connect on (optional)
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If \c other is omitted, then \c source is used instead (which must be a \c connectable_observable).
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Otherwise, \c source can be a regular \c observable.
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\return An \c observable that emits the items from its \c source.
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\sample
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\snippet ref_count.cpp ref_count other diamond sample
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\snippet output.txt ref_count other diamond sample
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*/
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#if !defined(RXCPP_OPERATORS_RX_REF_COUNT_HPP)
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#define RXCPP_OPERATORS_RX_REF_COUNT_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 ref_count_invalid_arguments {};
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template<class... AN>
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struct ref_count_invalid : public rxo::operator_base<ref_count_invalid_arguments<AN...>> {
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using type = observable<ref_count_invalid_arguments<AN...>, ref_count_invalid<AN...>>;
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};
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template<class... AN>
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using ref_count_invalid_t = typename ref_count_invalid<AN...>::type;
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// ref_count(other) takes a regular observable source, not a connectable_observable.
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// use template specialization to avoid instantiating 'subscribe' for two different types
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// which would cause a compilation error.
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template <typename connectable_type, typename observable_type>
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struct ref_count_state_base {
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ref_count_state_base(connectable_type other, observable_type source)
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: connectable(std::move(other))
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, subscribable(std::move(source)) {}
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connectable_type connectable; // connects to this. subscribes to this if subscribable empty.
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observable_type subscribable; // subscribes to this if non-empty.
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template <typename Subscriber>
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void subscribe(Subscriber&& o) {
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subscribable.subscribe(std::forward<Subscriber>(o));
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}
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};
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// Note: explicit specializations have to be at namespace scope prior to C++17.
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template <typename connectable_type>
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struct ref_count_state_base<connectable_type, void> {
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explicit ref_count_state_base(connectable_type c)
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: connectable(std::move(c)) {}
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connectable_type connectable; // connects to this. subscribes to this if subscribable empty.
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template <typename Subscriber>
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void subscribe(Subscriber&& o) {
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connectable.subscribe(std::forward<Subscriber>(o));
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}
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};
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template<class T,
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class ConnectableObservable,
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class Observable = void> // note: type order flipped versus the operator.
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struct ref_count : public operator_base<T>
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{
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typedef rxu::decay_t<Observable> observable_type;
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typedef rxu::decay_t<ConnectableObservable> connectable_type;
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// ref_count() == false
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// ref_count(other) == true
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using has_observable_t = rxu::negation<std::is_same<void, Observable>>;
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// removed constexpr to support older VC compilers
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static /*constexpr */ const bool has_observable_v = has_observable_t::value;
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struct ref_count_state : public std::enable_shared_from_this<ref_count_state>,
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public ref_count_state_base<ConnectableObservable, Observable>
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{
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template <class HasObservable = has_observable_t,
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class Enabled = rxu::enable_if_all_true_type_t<
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rxu::negation<HasObservable>>>
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explicit ref_count_state(connectable_type source)
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: ref_count_state_base<ConnectableObservable, Observable>(std::move(source))
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, subscribers(0)
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{
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}
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template <bool HasObservableV = has_observable_v>
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ref_count_state(connectable_type other,
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typename std::enable_if<HasObservableV, observable_type>::type source)
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: ref_count_state_base<ConnectableObservable, Observable>(std::move(other),
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std::move(source))
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, subscribers(0)
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{
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}
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std::mutex lock;
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long subscribers;
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composite_subscription connection;
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};
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std::shared_ptr<ref_count_state> state;
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// connectable_observable<T> source = ...;
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// source.ref_count();
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//
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// calls connect on source after the subscribe on source.
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template <class HasObservable = has_observable_t,
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class Enabled = rxu::enable_if_all_true_type_t<
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rxu::negation<HasObservable>>>
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explicit ref_count(connectable_type source)
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: state(std::make_shared<ref_count_state>(std::move(source)))
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{
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}
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// connectable_observable<?> other = ...;
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// observable<T> source = ...;
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// source.ref_count(other);
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//
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// calls connect on 'other' after the subscribe on 'source'.
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template <bool HasObservableV = has_observable_v>
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ref_count(connectable_type other,
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typename std::enable_if<HasObservableV, observable_type>::type source)
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: state(std::make_shared<ref_count_state>(std::move(other), std::move(source)))
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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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std::unique_lock<std::mutex> guard(state->lock);
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auto needConnect = ++state->subscribers == 1;
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auto keepAlive = state;
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guard.unlock();
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o.add(
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[keepAlive](){
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std::unique_lock<std::mutex> guard_unsubscribe(keepAlive->lock);
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if (--keepAlive->subscribers == 0) {
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keepAlive->connection.unsubscribe();
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keepAlive->connection = composite_subscription();
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}
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});
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keepAlive->subscribe(std::forward<Subscriber>(o));
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if (needConnect) {
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keepAlive->connectable.connect(keepAlive->connection);
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}
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}
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};
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}
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/*! @copydoc rx-ref_count.hpp
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*/
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template<class... AN>
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auto ref_count(AN&&... an)
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-> operator_factory<ref_count_tag, AN...> {
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return operator_factory<ref_count_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<ref_count_tag>
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{
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template<class ConnectableObservable,
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class Enabled = rxu::enable_if_all_true_type_t<
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is_connectable_observable<ConnectableObservable>>,
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class SourceValue = rxu::value_type_t<ConnectableObservable>,
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class RefCount = rxo::detail::ref_count<SourceValue, rxu::decay_t<ConnectableObservable>>,
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class Value = rxu::value_type_t<RefCount>,
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class Result = observable<Value, RefCount>
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>
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static Result member(ConnectableObservable&& o) {
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return Result(RefCount(std::forward<ConnectableObservable>(o)));
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}
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template<class Observable,
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class ConnectableObservable,
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class Enabled = rxu::enable_if_all_true_type_t<
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is_observable<Observable>,
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is_connectable_observable<ConnectableObservable>>,
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class SourceValue = rxu::value_type_t<Observable>,
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class RefCount = rxo::detail::ref_count<SourceValue,
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rxu::decay_t<ConnectableObservable>,
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rxu::decay_t<Observable>>,
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class Value = rxu::value_type_t<RefCount>,
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class Result = observable<Value, RefCount>
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>
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static Result member(Observable&& o, ConnectableObservable&& other) {
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return Result(RefCount(std::forward<ConnectableObservable>(other),
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std::forward<Observable>(o)));
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}
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template<class... AN>
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static operators::detail::ref_count_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, "ref_count takes (optional ConnectableObservable)");
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}
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};
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}
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#endif
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