Summary:
The "reparenting differ" has been the default differ for several months; ship it by removing config and the old differ.
Some functions can't be deleted yet because unit testing relies on it heavily; this can be refactored in the future if we care a lot.
Changelog: [Internal]
Reviewed By: mdvacca
Differential Revision: D25257205
fbshipit-source-id: 6f1dcc490bb1efe3d12506addf5f0843ca48c5c6
Summary:
Changelog: [internal]
Previous implementation of coalescing would only look at the last element in `eventQueue_` and if it was the same type and target, it would coalesce the two together. This was problem when user would scroll in UIScrollView, this triggers onTouchMove and onScroll events at high rates and prevents coalescing of them.
This changes changes the behaviour to search the `eventQueue_` backwards for an event of the same type and target. If one if found, it is moved into its place. If even of another type is found before for the same target, the event is pushed back onto the queue.
Reviewed By: JoshuaGross
Differential Revision: D24992941
fbshipit-source-id: fc1eae4ecd100af6202346674778b0634ed7a15b
Summary:
This enables a new state auto repeating mechanism built-in mechanism for all state updates which we already use for CK interop. This experiment is supposed to help with T74769670 and co.
This change is gated with MC.
Changelog: [Internal] Fabric-specific internal change.
Reviewed By: JoshuaGross
Differential Revision: D23762508
fbshipit-source-id: f535513c724ace9ede570177281324eb507329c5
Summary:
We don't need a shared_ptr here and without it the code will be faster and simpler.
This change is aligned with any clone-line callbacks we have in the Core which accepts a `const &` and return `shared_ptr<>`.
Changelog: [Internal] Fabric-specific internal change.
Reviewed By: JoshuaGross, sammy-SC
Differential Revision: D23725687
fbshipit-source-id: 1cd959f4273913175d342302e2f12752f0114768
Summary:
Previously, to get a current root shadow node for a shadow tree, we called `tryCommit` method and stole a pointer from this. That was not a very straightforward method to get things done, and most importantly we need to do this to change the shape of the ShadowTreeCommitTransaction signature (remove a shared pointer from the callback) to make it simpler, faster and allow future improvements (see the next diff).
Changelog: [Internal] Fabric-specific internal change.
Reviewed By: JoshuaGross, sammy-SC
Differential Revision: D23725689
fbshipit-source-id: 51950b843a0e401828b6c6a38e5e2aaaf21ec166
Summary:
One of the operations we do in `Scheduler::stopSurface()` is committing an empty tree to free up `ShadowNode` objects and "disable" `EventEmitter`s associated with them. Before this change, we had a gap in time between a moment when we commit an empty tree and remove the tree from the registry. During this time gap, JavaScript (or native, actually) can commit another tree and mount another new state on the screen. To prevent this, we remove the tree from the registry first and only then commit an empty tree to a uniquely owned tree.
Note that the deleted comment says that we actually have to have a tree in the registry for committing an empty tree, I don't think it's true now.
Changelog: [Internal] Fabric-specific internal change.
Reviewed By: sammy-SC
Differential Revision: D23667882
fbshipit-source-id: 387052e9f3e78e7d4446f36baed50f9caa831133
Summary:
# Summary
In previous diffs earlier in 2020, we made changes to detect and optimize reordering of views when the order of views changed underneath the same parent.
However, until now we have ignored reparenting and there's evidence of issues because of that. Because Fabric flattens views more aggressively, reparenting is also marginally more likely to happen.
This diff introduces a very general Reparenting detection. It will work with view flattening/unflattening, as well as tree grafting - subtrees moved to entirely different parts of the tree, not just a single
parent disappearing or reappearing because of flattening/unflattening.
There is also another consideration: previously, we were generating strictly too many Create+Delete operations that were redundant and could cause consistency issues, crashes, or bugs on platforms that do not handle that gracefully -
especially since the ordering of the Create+Delete is not guaranteed (a reparented view could be created "first" and then the differ could later issue a "delete" for the same view).
Intuition behind how it works: we know the cases where we can detect reparenting: it's when nodes are *not* matched up with another node from the other tree, and we're either trying to delete an entire subtree, or create an entire subtree. For perf reasons, we generate whatever set of operations comes first (say, we generate all the Delete and Remove instructions) and take note in the `ReparentingMetadata` data-structure that Delete and/or Remove have been performed for each tag (if ordering is different, we do the same for Create+Insert if those come first). Then if we later detect a corresponding subtree creation/deletion, we don't generate those mutations and we mark the previous mutations for deletion. This incurs some map lookup cost, but this is only wasteful for commits where a large tree is deleted and a large tree is created, without reparenting.
We may be able to improve perf further for certain edge-cases in the future.
# Why can't we solve this in JS?
Two things:
1. We certainly can avoid reparenting situations in JS, but it's trickier than before because of Fabric's view flattening logic - product engineers would have to think much harder about how to prevent reparenting in the general case.
2. In the case of specific views like BottomSheet that may crash if they're reparented, the solution is to make sure that the BottomSheet and the first child of the BottomSheet is never memoized, so that lifecycle functions and render are called more often; and that in every render, the BottomSheet manually clones its child, so that when the Views are recreated, the child of the BottomSheet has a tag and is an entirely different instance. This is certainly possible to do but feels like an onerous requirement for product teams, and it could be challenging to track down every specific BottomSheet that is memoized and/or hoist them higher in the view hierarchy so they're not reparented as often.
Reviewed By: shergin
Differential Revision: D23123575
fbshipit-source-id: 2fa7e1f026f87b6f0c60cad469a3ba85cdc234de
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
Joshua Gross
Samuel Susla
Valentin Shergin
Stephy Ma
David Vacca