mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
Valentin SherginandFacebook Github Bot
c80192c2ab
Summary: The purpose of `EventBeat` is handling an asynchronous callback to itself which is being delivered on some different thread. That brings a challenge of ensuring that the `EventBeat` object stays valid during the timeframe of callback execution. The concept of Owner helps with that. The owner is a shared pointer that retains (probably indirectly) the `EventBeat` object. To ensure the correctness of the call, `EventBeat` retains the owner (practically creating a retain cycle) during executing the callback. In case if the pointer to the owner already null, `EventBeat` skips executing the callback. It's impossible to retain itself directly or refer to the shared pointer to itself from a constructor. `OwnerBox` is designed to work around this issue; it allows to store the pointer later, right after the creation of some other object that owns an `EventBeat`. Reviewed By: JoshuaGross Differential Revision: D17128549 fbshipit-source-id: 7ed34fd865430975157fd362f51c4a3d64214430
70 lines
2.1 KiB
C++
70 lines
2.1 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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#include "EventDispatcher.h"
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#include <react/core/StateUpdate.h>
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#include "BatchedEventQueue.h"
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#include "RawEvent.h"
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#include "UnbatchedEventQueue.h"
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#define REACT_FABRIC_SYNC_EVENT_DISPATCHING_DISABLED
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namespace facebook {
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namespace react {
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EventDispatcher::EventDispatcher(
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EventPipe const &eventPipe,
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StatePipe const &statePipe,
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EventBeat::Factory const &synchonousEventBeatFactory,
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EventBeat::Factory const &asynchonousEventBeatFactory,
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EventBeat::SharedOwnerBox const &ownerBox) {
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// Synchronous/Unbatched
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eventQueues_[(int)EventPriority::SynchronousUnbatched] =
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std::make_unique<UnbatchedEventQueue>(
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eventPipe, statePipe, synchonousEventBeatFactory(ownerBox));
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// Synchronous/Batched
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eventQueues_[(int)EventPriority::SynchronousBatched] =
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std::make_unique<BatchedEventQueue>(
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eventPipe, statePipe, synchonousEventBeatFactory(ownerBox));
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// Asynchronous/Unbatched
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eventQueues_[(int)EventPriority::AsynchronousUnbatched] =
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std::make_unique<UnbatchedEventQueue>(
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eventPipe, statePipe, asynchonousEventBeatFactory(ownerBox));
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// Asynchronous/Batched
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eventQueues_[(int)EventPriority::AsynchronousBatched] =
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std::make_unique<BatchedEventQueue>(
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eventPipe, statePipe, asynchonousEventBeatFactory(ownerBox));
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}
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void EventDispatcher::dispatchEvent(
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RawEvent const &rawEvent,
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EventPriority priority) const {
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getEventQueue(priority).enqueueEvent(std::move(rawEvent));
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}
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void EventDispatcher::dispatchStateUpdate(
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StateUpdate &&stateUpdate,
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EventPriority priority) const {
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getEventQueue(priority).enqueueStateUpdate(std::move(stateUpdate));
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}
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const EventQueue &EventDispatcher::getEventQueue(EventPriority priority) const {
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#ifdef REACT_FABRIC_SYNC_EVENT_DISPATCHING_DISABLED
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priority = EventPriority::AsynchronousBatched;
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#endif
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return *eventQueues_[(int)priority];
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}
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} // namespace react
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} // namespace facebook
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