Avoid redundant dynamic_pointer_cast in YogaLayoutableShadowNode clone (#57019)#57019
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facebook#57019) Summary: The clone constructor of `YogaLayoutableShadowNode` rebuilt the internal `yogaLayoutableChildren_` vector on every clone by walking every child with `dynamic_pointer_cast`. When the cloned node inherits its children list from the source (`!fragment.children`) the result is identical to the source's vector, so copy it directly instead — no RTTI required. Also `reserve()` the vector to its upper bound at the top of `updateYogaChildren()` so the rebuild on the new-children path no longer reallocates as it grows. Both changes are pure CPU-time optimizations on a hot path that shows up heavily in animation-driven tree clones; behaviour is unchanged. Changelog: [Internal] Reviewed By: christophpurrer, lenaic Differential Revision: D106287171
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Summary:
The clone constructor of
YogaLayoutableShadowNoderebuilt theinternal
yogaLayoutableChildren_vector on every clone bywalking every child with
dynamic_pointer_cast. When the clonednode inherits its children list from the source (
!fragment.children)the result is identical to the source's vector, so copy it directly
instead — no RTTI required.
Also
reserve()the vector to its upper bound at the top ofupdateYogaChildren()so the rebuild on the new-children path nolonger reallocates as it grows.
Both changes are pure CPU-time optimizations on a hot path that
shows up heavily in animation-driven tree clones; behaviour is
unchanged.
Changelog:
[Internal]
Reviewed By: christophpurrer, lenaic
Differential Revision: D106287171