Files
react-native/ReactCommon/react/renderer/scheduler/SchedulerDelegate.h
T
Joshua Gross f2e0b2f45f Fix crash in PreAllocation optimization
Summary:
PreAllocation currently always happens at revision 0 (after ShadowNode creation), and all CREATE mutations are triggered for ShadowNodes at revision 1 or higher (since CREATE mutations are generated by the differ, it means that all ShadowNodes have revision 1 or higher when CompleteRoot is called). This means that between PreAllocation and CREATE, we /always/ expect at least one clone.

It is possible for a node to be "non-view-forming" at revision 0, causing view preallocation to be skipped, and "view-forming" at revision 1 (causing the CREATE mutation to be thrown away, since all CREATE mutations of revision 0 or 1 are thrown away). This causes a crash. It is extremely marginal, but there are repros in the wild.

Thus, I'm introducing one new UIManager and Scheduler delegate method that allows the mounting layer to be notified of clones. If a clone from rev 0->1 results in a node going from non-view-forming to view-forming, we can preallocate then, as well.

This resolves this crash, and allows us to keep experimenting safely with this View PreAllocation optimization. I believe all edge-cases are accounted for.

Changelog: [Internal]

Reviewed By: sammy-SC

Differential Revision: D29043426

fbshipit-source-id: dff11d3140ded1cbb02a5518a3aeb52dc812cc50
2021-06-10 15:50:14 -07:00

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1.8 KiB
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/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <memory>
#include <react/renderer/core/ReactPrimitives.h>
#include <react/renderer/mounting/MountingCoordinator.h>
#include <react/renderer/mounting/ShadowView.h>
namespace facebook {
namespace react {
/*
* Abstract class for Scheduler's delegate.
*/
class SchedulerDelegate {
public:
/*
* Called right after Scheduler computed (and laid out) a new updated version
* of the tree and calculated a set of mutations which are sufficient
* to construct a new one.
*/
virtual void schedulerDidFinishTransaction(
MountingCoordinator::Shared const &mountingCoordinator) = 0;
/*
* Called right after a new ShadowNode was created.
*/
virtual void schedulerDidRequestPreliminaryViewAllocation(
SurfaceId surfaceId,
const ShadowNode &shadowView) = 0;
/*
* Called right after a ShadowNode is cloned.
*/
virtual void schedulerDidCloneShadowNode(
SurfaceId surfaceId,
const ShadowNode &oldShadowNode,
const ShadowNode &newShadowNode) = 0;
virtual void schedulerDidDispatchCommand(
const ShadowView &shadowView,
std::string const &commandName,
folly::dynamic const args) = 0;
virtual void schedulerDidSendAccessibilityEvent(
const ShadowView &shadowView,
std::string const &eventType) = 0;
/*
* Set JS responder for a view
*/
virtual void schedulerDidSetIsJSResponder(
ShadowView const &shadowView,
bool isJSResponder,
bool blockNativeResponder) = 0;
virtual ~SchedulerDelegate() noexcept = default;
};
} // namespace react
} // namespace facebook