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https://github.com/facebook/react-native.git
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Valentin Shergin
948398519d
Summary: Accidentally I noticed that the signature of Folly's hash_combine is different from boost's one. The Folly's one is: `size_t hash_combine(const T& t, const Ts&... ts)`, so the first argument is immutable and the method returns the result normally. It means that all hashes that we compute in Fabric using `hash_combine` were `0`. So I fixed it. I have no idea why this difference exists, but some modern papers suggest that folly's variant has good chances to be standardized. E.g.: http://open-std.org/JTC1/SC22/WG21/docs/papers/2017/p0814r0.pdf Technically, it should improve performance, but I doubt that it can be more than 1-2 ms per screen TTI. Reviewed By: JoshuaGross Differential Revision: D14430380 fbshipit-source-id: 97da999ee5780b940bb789bc3eb5bf9f89c194ca
55 lines
1.3 KiB
C++
55 lines
1.3 KiB
C++
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <folly/Hash.h>
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#include <react/core/LayoutPrimitives.h>
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#include <react/graphics/Geometry.h>
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namespace facebook {
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namespace react {
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/*
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* Unified layout constraints for measuring.
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*/
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struct LayoutConstraints {
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Size minimumSize{0, 0};
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Size maximumSize{kFloatUndefined, kFloatUndefined};
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LayoutDirection layoutDirection{LayoutDirection::Undefined};
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/*
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* Clamps the provided `Size` between the `minimumSize` and `maximumSize`
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* bounds of this `LayoutConstraints`.
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*/
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Size clamp(const Size &size) const;
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};
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inline bool operator==(
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const LayoutConstraints &lhs,
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const LayoutConstraints &rhs) {
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return std::tie(lhs.minimumSize, lhs.maximumSize, lhs.layoutDirection) ==
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std::tie(rhs.minimumSize, rhs.maximumSize, rhs.layoutDirection);
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}
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} // namespace react
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} // namespace facebook
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namespace std {
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template <>
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struct hash<facebook::react::LayoutConstraints> {
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size_t operator()(
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const facebook::react::LayoutConstraints &constraints) const {
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return folly::hash::hash_combine(
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0,
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constraints.minimumSize,
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constraints.maximumSize,
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constraints.layoutDirection);
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}
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};
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} // namespace std
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