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
Summary:
Changelog:
[Android][Fixed] - Fix regression when setting shadow node properties.
Also simplified the corresponding macros to avoid using lambdas altogether, as they are not required.
Note that this **does not** modify any constexpr-related semantics of the existing code, as the main constexpr macro, `CONSTEXPR_RAW_PROPS_KEY_HASH` evaluation result is still contstexpr value, and the other ones already involved non-const parts (see my comments).
Reviewed By: NickGerleman
Differential Revision: D38356411
fbshipit-source-id: 22c330d3425c8aed36693f4652f1b257d2dc96be
Summary:
Fix macro errors for Windows. Current syntax breaks the build of the React Common project on Windows because the ({...}) syntax is not supported; must be replaced with lambda expressions.
Resolves https://github.com/facebook/react-native/issues/34090
## Changelog
<!-- Help reviewers and the release process by writing your own changelog entry. For an example, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests
-->
[General] [Fixed] - Fix macro errors for Windows.
lyahdav JoshuaGross
Pull Request resolved: https://github.com/facebook/react-native/pull/34299
Test Plan: Build on react-native-windows repo. Tested in RNW app.
Reviewed By: javache
Differential Revision: D38272966
Pulled By: NickGerleman
fbshipit-source-id: e76eac11cde173ef49465d01d793c593017f2ab7
Summary: Changelog: [Internal] - We can now remove the '2' suffix as we had an internal implementation that was not truly aligned with W3C pointers but used the same name. We have aligned the internal types to match w3c so we can now remove the suffix that differentiates them.
Reviewed By: vincentriemer
Differential Revision: D37545813
fbshipit-source-id: 6f2336ae9e314066c340161113268c1f28621a71
Summary:
Perf numbers for this stack are given in terms of before-stack and after-stack, but the changes are split up for ease of review, and also to show that this migration CAN happen per-component and is 100% opt-in. Most existing C++ components do not /need/ to change at all.
# Problem Statement
During certain renders (select critical scenarios in specific products), UIManagerBinding::createNode time takes over 50% of JS thread CPU time. This could be higher or lower depending on the specific product and interaction, but overall createNode takes a lot of CPU time. The question is: can we improve this? What is the minimal overhead needed?
The vast, vast majority of time is taken up by prop parsing (specifically, converting JS values across the JSI into concrete values on the C++ props structs). Other methods like appendChild, etc, do not take up a significant amount of time; so we conclude that createNode is special, and the JSI itself, or calling into C++, is not the problem. Props parsing is the perf problem.
Can we improve it? (Spoiler: yes)
# How does props parsing work today?
Today, props parsing works as follows:
1. The ConcreteComponentDescriptor will construct a RawPropsParser (one per component /type/, per application: so one for View, one for Image, one for Text... etc)
2. Once per component type per application, ConcreteComponentDescriptor will call "prepare" on the RawPropsParser with an empty, default-constructed ConcreteProps struct. This ConcreteProps struct will cause RawProps.at(field) for every single field.
3. Based on the RawProps::at calls in part 2, RawPropsParser constructs a Map from props string names (width, height, position, etc) to a position within a "value index" array.
4. The above is what happens before any actual props are parsed; and the RawPropsParser is now ready to parse actual Props.
5. When props are actually being parsed from a JSI dictionary, we now have two phases:
1. The RawPropsParser `preparse`s the RawProps, by iterating over the JSI map and filling in two additional data structures: a linear list of RawValues, and a mapping from the ValueIndex array (`keyIndexToValueIndex_`; see step 3) to a value's position in the values list (`value_` in RawPropsParser/RawProps);
2. The ConcretePropT constructor is called, which is the same as in step 2/3, which calls `fieldValue = rawProps.at("fieldName")` repeatedly.
3. For each `at` call, the RawProps will look up a prop name in the Map constructed in step 3, and either return an empty value, or map the key name to the `keyIndexToValueIndex_` array, which maps to a value in `values_`, which is then returned and further parsed.
So, a few things that become clear with the current architecture:
1. Complexity is a property of the number of /possible/ props that /can/ be parsed, not what is actually used in product code. This violates the "only pay for what you use" principal. If you have `<View opacity={0.5} />`, the ViewProps constructor will request ~170 properties, not 1!
2. There's a lot of pre-parsing which isn't free
3. The levels of indirection aren't free, and make cache misses more likely and pipelining is more challenging
4. The levels of indirection also require more memory - minor, but not free
# How can we improve it?
The goal is to improve props parsing with minimal or zero impact on backwards-compability. We should be able to migrate over components when it's clear there's a performance issue, without requiring everything gets migrated over at once. This both (1) helps us prove out the new architecture, (2) derisks the project, (3) gives us time, internally and externally, to perfect the APIs and gradually migrate everything over before deleting the old infrastructure code entirely.
Thus, the goal is to do something that introduces a zero-cost abstraction. This isn't entirely possible in practice, and in fact this method slightly regresses components that do not use the new architecture /at all/, while dramatically improving migrated components and causing the impact of the /old/ architecture to be minimal.
# Solution
1. We still keep the existing system in place entirely.
2. After Props are constructed (see ConcreteComponentDescriptor changes) we iterate over all the /values/ set from JS, and call PropsT::setProp. Incidentally, this allows us to easily reuse the same prop for multiple values for "free", which was expensive in the old system.
3. It's worth noting that this makes a Props struct "less immutable" than it was before, and essentially now we have a "builder pattern" for Props. (If we really wanted to, we could still require a single constructor for Props, and then actually use an intermediate PropsBuilder to accumulate values - but I don't think this overhead would be worth for the conceptual "immutability" win, and instead a "Construct/Set/Seal" model works fine, and we still have all the same guarantees of immutability after the parsing phase)
# Implementation Details
# How to properly construct a single Prop value
Minor detail: parsing a single prop is a 3-step process. We imagine two scenarios: (1) Creating a new ShadowNode/Props A from nothing/void, so the previous Props value is just the default constructor. (2) Cloning a ShadowNode A->B and therefore Props A must be copied to Props B before parsing.
We will denote this as a clone from A->B, where A may or may not be a previous node or a default-constructed Props node; and imagine in particular that we're setting the "opacity" value for PropsB.
We must first (1) copy a value over from the previous version of the Props struct, so B.opacity = A.opacity; (2) Determine if opacity has been set from JS. If so, and there is a value, B.opacity = parse(JSValue). (3) If JS has passed in a value for the prop, BUT the value is `null`, it means that JS is resetting or deleting the prop, so we must set it BACK to the default. In this case we set PropsB.opacity = DefaultConstructedProps.opacity.
We must take care in general to ensure that the correct behavior is achieved here, which should help to explain some of the code below.
## String comparisons vs hash comparisons
In the previous system, a RawPropsKey is three `const char*` strings, concatenated together repeatedly /at runtime/. In practice, the ONLY reason we have the prefix, name, suffix Key structure is for the templated prop parsing in ViewProps and YogaStyableProps - that's it. It's not used anywhere else. Further, the key {"margin", "Left", "Width"} is identical to the key {"marginLeftWidth", null, null} and we don't do anything fancy with matching prefixes before comparing the whole string, or similar. Before comparison, keys are concatenated into a single string and then we use `strcmp`. The performance of this isn't terrible, but it's nonzero overhead.
I think we can do better and it's sufficient to compare hashed string values; even better, we can construct most of these /at compile time/ using constexpr, and using `switch` statements guarantee no hash collisions within a single Props struct (it's possible there's a collision between Props.cpp and ViewProps.cpp, for example, since they're different switch statements). We may eventually want to be more robust against has collisions; I personally don't find the risk to be too great, hash collisions with these keys are exceedingly unlikely (or maybe I just like to live dangerously). Thus, at runtime, each setProp requires computing a single hash for the value coming from JS, and then int comparisons with a bunch of pre-compiled values.
If we want to be really paranoid, we could be robust to hash collisions by doing `switch COMPILED_HASH("opacity"): if (strcmp(strFromJs, "opacity") == 0)`. I'm happy to do this if there's enough concern.
## Macros
Yuck! I'm using lots of C preprocessor macros. In general I found this way, way easier in reducing code and (essentially) doing codegen for me vs templated code for the switch cases and hashing prop names at compile-time. Maybe there's a better way.
Changelog: [Added][Fabric] New API for efficient props construction
Reviewed By: javache
Differential Revision: D37050215
fbshipit-source-id: d2dcd351a93b9715cfeb5197eb0d6f9194ec6eb9
Summary:
Without getting into the weeds too much, RawPropParser "requires" that props be accessed in the same order every time a Props struct is parsed in order to most optimally fetch the values in a linear-ish fashion, basically ensuring that each rawProps.at() call is an O(1) operation, and overall getting all props for a particular component is O(n) in the number of props for a given struct. If props are called out of order, this breaks and worst-case we can end up with an O(n^2) operation.
Unfortunately, calling .at(x) twice with the same prop name triggers the deoptimized behavior. So as much as possible, always fetch exactly once and in the same order every time. In this case, we move initialization of two fields into the constructor body so that we can call .at() a single time instead of twice.
In the debug props of ViewProps I'm also reordering the fields to fetch them in the same order the constructor fetches them in, which will make this (debug-only) method slightly faster.
What's the impact of this? If you dig into the Tracery samples, the average/median RawPropsParser::at takes 1us or less. However, in /every single/ call to createNode for View components, there is at least one RawPropsParser::at call that takes 250+us. This was a huge red flag when analyzing traces, after which it was trivial (for View) to find the offending out-of-order calls. Since this is happening for every View and every type of component that derives from View, that's 1ms lost per every 4 View-type ShadowNodes created by ReactJS. After just 100 views created, that's 25ms. Etc.
There are other out-of-order calls lurking in the codebase that can be addressed separately. Impact scales with the size of the screen, the number of Views they render, etc.
Changelog: [Internal]
Reviewed By: mdvacca
Differential Revision: D36889794
fbshipit-source-id: 91e0a7ca39ed10778e60a0f0339a4b4dc8b14436
Summary:
With the `MapBuffer`-based props calculated from C++ props, there's no need to keep `rawProps` around for Android views.
This change makes sure that the `rawProps` field is only initialized under the feature flag that is responsible for enabling `MapBuffer` for prop diffing, potentially decreasing memory footprint and speeding up node initialization as JS props don't have to be converted to `folly::dynamic` anymore.
For layout animations, props rely on C++ values, so there's no need to update `rawProps` values either.
Changelog: [Internal][Android] - Do not init `rawProps` when mapbuffer serialization is used for ViewProps.
Reviewed By: mdvacca
Differential Revision: D33793044
fbshipit-source-id: 35873b10d3ca8b152b25344ef2c27aff9641846f
Summary:
Parses a set of props previously missing from C++ representation (they weren't required for iOS and core processing before).
Changelog: [Internal] - Added missing fields for Android to C++ view props
Reviewed By: sammy-SC
Differential Revision: D33797489
fbshipit-source-id: 1625baa0c1a592fcef409a5f206496dff0368912
Summary:
The views with touch event props are currently flattened by Fabric core, as we don't take event listeners into account when calculating whether the view should be flattened. This results in a confusing situation when components with touch event listeners (e.g. `<View onTouchStart={() => {}} /> `) or ones using `PanResponder` are either ignored (iOS) or cause a crash (Android).
This change passes touch event props to C++ layer and uses them to calculate whether the view node should be flattened or not. It also refactors events to be kept as a singular bitset with 32 bit (~`uint32_t`).
Changelog: [Changed][General] Avoid flattening nodes with event props
Reviewed By: sammy-SC
Differential Revision: D34005536
fbshipit-source-id: 96255b389a7bfff4aa208a96fd0c173d9edf1512
Summary:
This diff updates the internals of Fabric to add support for onEnter/onExit/onMove events.
changelog: [internal] internal
Reviewed By: javache
Differential Revision: D32253128
fbshipit-source-id: 5b30e927bda0328ba1332801f66a6caba77f949b
Summary:
See previous diffs for context. This updates all of the relevant props structs.
Changelog: [Internal]
Reviewed By: mdvacca
Differential Revision: D29855426
fbshipit-source-id: 30177c3380ef82ecf8f2a4321f128cfbe8a576e0
Summary:
Changelog: [internal]
Fabric didn't have prop [removeClippedSubviews](https://reactnative.dev/docs/view#removeclippedsubviews) implemented. This diff adds it. It is
Reviewed By: JoshuaGross
Differential Revision: D29906458
fbshipit-source-id: 5851fa41d7facea9aab73ca131b4a0d23a2411ea
Summary:
This diff moves fabric C++ code from ReactCommon/fabric to ReactCommon/react/renderer
As part of this diff I also refactored components, codegen and callsites on CatalystApp, FB4A and venice
Script: P137350694
changelog: [internal] internal refactor
Reviewed By: fkgozali
Differential Revision: D22852139
fbshipit-source-id: f85310ba858b6afd81abfd9cbe6d70b28eca7415
Ruslan Shestopalyuk
Ruslan Shestopalyuk
Chiara Mooney
Eric Edouard
Luna Wei
Joshua Gross
Andrei Shikov
Andres Suarez
David Vacca
Samuel Susla
