Summary:
changelog: [internal]
This diff introduces a mechanism to cache NSTextStorage on Paragraph's state. The old renderer already has caching for NSTextStorage: https://github.com/facebook/react-native/blob/main/Libraries/Text/Text/RCTTextShadowView.m#L21
Fabric will store `NSTextStorage` inside `ParagraphLayoutManager` which is owned by state.
There is one notable change which is not gated: Paragraph's state strongly owns `TextLayoutManager`, not `ParagraphShadowNode` like previously. This shouldn't change anything
Reviewed By: mdvacca
Differential Revision: D43692171
fbshipit-source-id: efe6077222a30ab6d89abd9916534b9a96e745d4
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/36395
NativeState is a lighter-weight alternative to HostObject, which may simplify some of our use-cases of interacting with JS in the renderer. The down-side is that this approach doesn't allow exposing custom props or functions.
This diffs adds new feature flags to enable experimenting with this functionality and measure any perf impact.
Changelog: [Internal]
Reviewed By: sammy-SC
Differential Revision: D41553421
fbshipit-source-id: 3065bd7b60f0fa7b63c390e92a785582eee7e613
Summary:
changelog: [internal]
`useLayoutEffect` has two guarantees which React Native breaks:
- Layout metrics are ready.
- Updates triggered inside `useLayoutEffect` are applied before paint. State between first commit and update is not shown on the screen.
React Native breaks the first guarantee because it uses Background Executor. Background executor moves Yoga layout to another thread. If user core reads layout metrics in `useLayoutEffect` hook, it is a race. The information might be there, or it might not. They can even read partially update information. This diff does not affect this. We already have a way to turn off Background Executor. We haven't done this because it introduces regressions on one screen but we have a solution for that.
React Native breaks the second guarantee. After Fabric's commit phase, Fabric moves to mounting the changes right away. In this diff, we queue the mounting phase and give React a chance to change what is committed to the screen. To do that, we schedule a task with user blocking priority in `RuntimeScheduler`. React, if there is an update in `useLayoutEffect`, schedules a task in the scheduler with higher priority and stops the mounting phase.
We are not delaying mounting, this just gives React a chance to interrupt it.
Fabric commit phase may be triggered by different mechanisms. C++ state update, surface tear down, template update (not used atm), setNativeProps, to name a few. Fabric only needs to block paint if commit originates from React. Otherwise the scheduling is wrong and we will get into undefined behaviour land.
Rollout:
This change is gated behind `react_fabric:block_paint_for_use_layout_effect` and will be rolled out incrementally.
Reviewed By: javache
Differential Revision: D43083051
fbshipit-source-id: bb494cf56a11763e38dce7ba0093c4dafdd8bf43
Summary:
A follow up to D38708718 (https://github.com/facebook/react-native/commit/403fea25f65a38f4b4d8e0edcf89741b29e62059) review, this factors feature flags for Fabric core code into a separate file, `CoreFeatures`.
Keeping them together is arguably better for maintenance and makes code easier to reason about.
Changelog: [Internal]
Reviewed By: sammy-SC
Differential Revision: D40007784
fbshipit-source-id: 1885d5d6200575c6015f063d8b05813b18b47ffb
Samuel Susla
Pieter De Baets
Ruslan Shestopalyuk