diff options
Diffstat (limited to 'Rx/v2/src/rxcpp/operators/rx-ref_count.hpp')
-rw-r--r-- | Rx/v2/src/rxcpp/operators/rx-ref_count.hpp | 134 |
1 files changed, 119 insertions, 15 deletions
diff --git a/Rx/v2/src/rxcpp/operators/rx-ref_count.hpp b/Rx/v2/src/rxcpp/operators/rx-ref_count.hpp index 55dde05..b68315d 100644 --- a/Rx/v2/src/rxcpp/operators/rx-ref_count.hpp +++ b/Rx/v2/src/rxcpp/operators/rx-ref_count.hpp @@ -4,10 +4,26 @@ /*! \file rx-ref_count.hpp - \brief takes a connectable_observable source and uses a ref_count of the subscribers to control the connection to the published source. - The first subscription will cause a call to connect() and the last unsubscribe will unsubscribe the connection. + \brief Make some \c connectable_observable behave like an ordinary \c observable. + Uses a reference count of the subscribers to control the connection to the published observable. - \return An observable that emitting the items from its source. + The first subscription will cause a call to \c connect(), and the last \c unsubscribe will unsubscribe the connection. + + There are 2 variants of the operator: + \li \c ref_count(): calls \c connect on the \c source \c connectable_observable. + \li \c ref_count(other): calls \c connect on the \c other \c connectable_observable. + + \tparam ConnectableObservable the type of the \c other \c connectable_observable (optional) + \param other \c connectable_observable to call \c connect on (optional) + + If \c other is omitted, then \c source is used instead (which must be a \c connectable_observable). + Otherwise, \c source can be a regular \c observable. + + \return An \c observable that emits the items from its \c source. + + \sample + \snippet ref_count.cpp ref_count other diamond sample + \snippet output.txt ref_count other diamond sample */ #if !defined(RXCPP_OPERATORS_RX_REF_COUNT_HPP) @@ -30,29 +46,100 @@ struct ref_count_invalid : public rxo::operator_base<ref_count_invalid_arguments }; template<class... AN> using ref_count_invalid_t = typename ref_count_invalid<AN...>::type; - -template<class T, class ConnectableObservable> + +// ref_count(other) takes a regular observable source, not a connectable_observable. +// use template specialization to avoid instantiating 'subscribe' for two different types +// which would cause a compilation error. +template <typename connectable_type, typename observable_type> +struct ref_count_state_base { + ref_count_state_base(connectable_type other, observable_type source) + : connectable(std::move(other)) + , subscribable(std::move(source)) {} + + connectable_type connectable; // connects to this. subscribes to this if subscribable empty. + observable_type subscribable; // subscribes to this if non-empty. + + template <typename Subscriber> + void subscribe(Subscriber&& o) { + subscribable.subscribe(std::forward<Subscriber>(o)); + } +}; + +// Note: explicit specializations have to be at namespace scope prior to C++17. +template <typename connectable_type> +struct ref_count_state_base<connectable_type, void> { + explicit ref_count_state_base(connectable_type c) + : connectable(std::move(c)) {} + + connectable_type connectable; // connects to this. subscribes to this if subscribable empty. + + template <typename Subscriber> + void subscribe(Subscriber&& o) { + connectable.subscribe(std::forward<Subscriber>(o)); + } +}; + +template<class T, + class ConnectableObservable, + class Observable = void> // note: type order flipped versus the operator. struct ref_count : public operator_base<T> { - typedef rxu::decay_t<ConnectableObservable> source_type; + typedef rxu::decay_t<Observable> observable_type; + typedef rxu::decay_t<ConnectableObservable> connectable_type; - struct ref_count_state : public std::enable_shared_from_this<ref_count_state> + // ref_count() == false + // ref_count(other) == true + using has_observable_t = rxu::negation<std::is_same<void, Observable>>; + static constexpr bool has_observable_v = has_observable_t::value; + + struct ref_count_state : public std::enable_shared_from_this<ref_count_state>, + public ref_count_state_base<ConnectableObservable, Observable> { - explicit ref_count_state(source_type o) - : source(std::move(o)) + template <class HasObservable = has_observable_t, + class Enabled = rxu::enable_if_all_true_type_t< + rxu::negation<HasObservable>>> + explicit ref_count_state(connectable_type source) + : ref_count_state_base<ConnectableObservable, Observable>(std::move(source)) + , subscribers(0) + { + } + + template <bool HasObservableV = has_observable_v> + ref_count_state(connectable_type other, + typename std::enable_if<HasObservableV, observable_type>::type source) + : ref_count_state_base<ConnectableObservable, Observable>(std::move(other), + std::move(source)) , subscribers(0) { } - source_type source; std::mutex lock; long subscribers; composite_subscription connection; }; std::shared_ptr<ref_count_state> state; - explicit ref_count(source_type o) - : state(std::make_shared<ref_count_state>(std::move(o))) + // connectable_observable<T> source = ...; + // source.ref_count(); + // + // calls connect on source after the subscribe on source. + template <class HasObservable = has_observable_t, + class Enabled = rxu::enable_if_all_true_type_t< + rxu::negation<HasObservable>>> + explicit ref_count(connectable_type source) + : state(std::make_shared<ref_count_state>(std::move(source))) + { + } + + // connectable_observable<?> other = ...; + // observable<T> source = ...; + // source.ref_count(other); + // + // calls connect on 'other' after the subscribe on 'source'. + template <bool HasObservableV = has_observable_v> + ref_count(connectable_type other, + typename std::enable_if<HasObservableV, observable_type>::type source) + : state(std::make_shared<ref_count_state>(std::move(other), std::move(source))) { } @@ -70,9 +157,9 @@ struct ref_count : public operator_base<T> keepAlive->connection = composite_subscription(); } }); - keepAlive->source.subscribe(std::forward<Subscriber>(o)); + keepAlive->subscribe(std::forward<Subscriber>(o)); if (needConnect) { - keepAlive->source.connect(keepAlive->connection); + keepAlive->connectable.connect(keepAlive->connection); } } }; @@ -104,11 +191,28 @@ struct member_overload<ref_count_tag> return Result(RefCount(std::forward<ConnectableObservable>(o))); } + template<class Observable, + class ConnectableObservable, + class Enabled = rxu::enable_if_all_true_type_t< + is_observable<Observable>, + is_connectable_observable<ConnectableObservable>>, + class SourceValue = rxu::value_type_t<Observable>, + class RefCount = rxo::detail::ref_count<SourceValue, + rxu::decay_t<ConnectableObservable>, + rxu::decay_t<Observable>>, + class Value = rxu::value_type_t<RefCount>, + class Result = observable<Value, RefCount> + > + static Result member(Observable&& o, ConnectableObservable&& other) { + return Result(RefCount(std::forward<ConnectableObservable>(other), + std::forward<Observable>(o))); + } + template<class... AN> static operators::detail::ref_count_invalid_t<AN...> member(AN...) { std::terminate(); return {}; - static_assert(sizeof...(AN) == 10000, "ref_count takes no arguments"); + static_assert(sizeof...(AN) == 10000, "ref_count takes (optional ConnectableObservable)"); } }; |