jiuyiUniapp/service/node_modules/react-native/React/Fabric/Mounting/RCTMountingTransactionObser...

67 lines
3.1 KiB
Objective-C

/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#import <UIKit/UIKit.h>
#include <react/renderer/mounting/MountingTransaction.h>
NS_ASSUME_NONNULL_BEGIN
/*
* # Achtung!
* Remember, with great power comes great responsibility.
* Observers of this protocol are being called several times on every single mount transaction. Any thoughtless or
* suboptimal implementation of this protocol will slow down the whole app. Please, be responsible.
*
* # Usecases
* React Native platform-specific mounting layer has limitations when it comes to notifying view components about
* (coming or just happened) changes in the view tree. Implementing that generically for all components would make
* everything way to slow. For instance, the mounting layer does not have dedicated APIs to notify some component that:
* - Some ancestor of the component was reparented;
* - Some descendant of the component was added, removed or reparented;
* - Some ancestor of the component got new layout metrics (which might affect the absolute position of the component);
* - The transaction which affected the component's children just finished.
*
* If some very specific component (e.g. a performance logger) needs to handle some of the similar use-cases, it might
* rely on this protocol.
*
* # How to use
* - Declare conformance to this protocol for the ComponentView class.
* - Implement methods *only* suitable for a particular use case. Do not implement all methods if it is not strictly
* required.
* - Alternatively, an observer can be registered explicitly via `RCTSurface`.
*
* # Implementation details
* The framework checks all registered view classes for conformance to the protocol and for a set of implemented
* methods, then it stores this information for future use. When a view got created, the framework checks the info
* associated with the class and adds the view object to the list of listeners of the particular events (if needed).
* When a view got destroyed, the framework removes the view from suitable collections.
*/
@protocol RCTMountingTransactionObserving <NSObject>
@optional
/*
* Called right before the fist mutation instruction is executed.
* Is not being called for a component view which is being mounted as part of the transaction (because the view is not
* registered as an observer yet).
*/
- (void)mountingTransactionWillMount:(const facebook::react::MountingTransaction &)transaction
withSurfaceTelemetry:(const facebook::react::SurfaceTelemetry &)surfaceTelemetry;
/*
* Called right after the last mutation instruction is executed.
* Is not being called for a component view which was being unmounted as part of the transaction (because the view is
* not registered as an observer already).
*/
- (void)mountingTransactionDidMount:(const facebook::react::MountingTransaction &)transaction
withSurfaceTelemetry:(const facebook::react::SurfaceTelemetry &)surfaceTelemetry;
@end
NS_ASSUME_NONNULL_END