93 lines
2.3 KiB
C++
93 lines
2.3 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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#if !defined(RXCPP_SOURCES_RX_CREATE_HPP)
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#define RXCPP_SOURCES_RX_CREATE_HPP
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#include "../rx-includes.hpp"
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/*! \file rx-create.hpp
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\brief Returns an observable that executes the specified function when a subscriber subscribes to it.
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\tparam T the type of the items that this observable emits
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\tparam OnSubscribe the type of OnSubscribe handler function
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\param os OnSubscribe event handler
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\return Observable that executes the specified function when a Subscriber subscribes to it.
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\sample
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\snippet create.cpp Create sample
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\snippet output.txt Create sample
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\warning
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It is good practice to check the observer's is_subscribed state from within the function you pass to create
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so that your observable can stop emitting items or doing expensive calculations when there is no longer an interested observer.
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\badcode
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\snippet create.cpp Create bad code
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\snippet output.txt Create bad code
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\goodcode
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\snippet create.cpp Create good code
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\snippet output.txt Create good code
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\warning
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It is good practice to use operators like observable::take to control lifetime rather than use the subscription explicitly.
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\goodcode
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\snippet create.cpp Create great code
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\snippet output.txt Create great code
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*/
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namespace rxcpp {
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namespace sources {
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namespace detail {
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template<class T, class OnSubscribe>
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struct create : public source_base<T>
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{
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typedef create<T, OnSubscribe> this_type;
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typedef rxu::decay_t<OnSubscribe> on_subscribe_type;
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on_subscribe_type on_subscribe_function;
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create(on_subscribe_type os)
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: on_subscribe_function(std::move(os))
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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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on_exception(
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[&](){
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this->on_subscribe_function(o);
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return true;
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},
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o);
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}
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};
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}
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/*! @copydoc rx-create.hpp
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*/
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template<class T, class OnSubscribe>
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auto create(OnSubscribe os)
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-> observable<T, detail::create<T, OnSubscribe>> {
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return observable<T, detail::create<T, OnSubscribe>>(
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detail::create<T, OnSubscribe>(std::move(os)));
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}
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}
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}
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#endif
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