93 строки
2.5 KiB
C++
93 строки
2.5 KiB
C++
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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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 <memory>
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#include <mutex>
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#include <folly/dynamic.h>
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#include <react/events/EventDispatcher.h>
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#include <react/events/primitives.h>
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namespace facebook {
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namespace react {
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class EventEmitter;
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using SharedEventEmitter = std::shared_ptr<const EventEmitter>;
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/*
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* Base class for all particular typed event handlers.
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* Stores a pointer to `EventTarget` identifying a particular component and
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* a weak pointer to `EventDispatcher` which is responsible for delivering the
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* event.
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*/
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class EventEmitter {
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/*
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* We have to repeat `Tag` type definition here because `events` module does
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* not depend on `core` module (and should not).
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*/
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using Tag = int32_t;
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public:
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static std::mutex &DispatchMutex();
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static ValueFactory defaultPayloadFactory();
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EventEmitter(
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SharedEventTarget eventTarget,
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Tag tag,
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WeakEventDispatcher eventDispatcher);
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virtual ~EventEmitter() = default;
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/*
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* Enables/disables event emitter.
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* Enabled event emitter retains a pointer to `eventTarget` strongly (as
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* `std::shared_ptr`) whereas disabled one don't.
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* Enabled/disabled state is also proxied to `eventTarget` where it indicates
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* a possibility to extract JSI value from it.
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* The enable state is additive; a number of `enable` calls should be equal to
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* a number of `disable` calls to release the event target.
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* `DispatchMutex` must be acquired before calling.
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*/
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void setEnabled(bool enabled) const;
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protected:
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#ifdef ANDROID
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// We need this temporarily due to lack of Java-counterparts for particular
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// subclasses.
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public:
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#endif
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/*
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* Initates an event delivery process.
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* Is used by particular subclasses only.
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*/
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void dispatchEvent(
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const std::string &type,
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const ValueFactory &payloadFactory =
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EventEmitter::defaultPayloadFactory(),
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const EventPriority &priority = EventPriority::AsynchronousBatched) const;
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void dispatchEvent(
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const std::string &type,
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const folly::dynamic &payload,
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const EventPriority &priority = EventPriority::AsynchronousBatched) const;
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private:
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void toggleEventTargetOwnership_() const;
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mutable SharedEventTarget eventTarget_;
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WeakEventDispatcher eventDispatcher_;
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mutable int enableCounter_{0};
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mutable bool isEnabled_{false};
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};
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} // namespace react
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} // namespace facebook
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