67 lines
1.7 KiB
C++
67 lines
1.7 KiB
C++
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <atomic>
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#include <functional>
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#include <memory>
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namespace facebook {
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namespace react {
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/*
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* Event Beat serves two interleaving purposes: synchronization of event queues and
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* ensuring that event dispatching happens on propper threads.
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*/
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class EventBeat {
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public:
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virtual ~EventBeat() = default;
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using BeatCallback = std::function<void()>;
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/*
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* Communicates to the Beat that a consumer is waiting for the coming beat.
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* A consumer must request coming beat after the previous beat happened
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* to receive a next coming one.
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*/
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virtual void request() const;
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/*
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* Induces the next beat to happen as soon as possible. If the method
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* is called on the proper thread, the beat must happen synchronously.
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* Subclasses might override this method to implement specific
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* out-of-turn beat scheduling.
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* Some types of Event Beats do not support inducing, hence the default
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* implementation does nothing.
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* Receiver might ignore the call if a beat was not requested.
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*/
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virtual void induce() const;
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/*
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* Sets a callback function.
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* The callback is must be called on the proper thread.
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*/
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void setBeatCallback(const BeatCallback &beatCallback);
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protected:
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/*
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* Should be used by sublasses to send a beat.
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* Receiver might ignore the call if a beat was not requested.
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*/
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void beat() const;
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BeatCallback beatCallback_;
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mutable std::atomic<bool> isRequested_ {false};
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};
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using EventBeatFactory = std::function<std::unique_ptr<EventBeat>()>;
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} // namespace react
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} // namespace facebook
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