59 lines
1.6 KiB
C++
59 lines
1.6 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and 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 <optional>
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#include <react/renderer/css/CSSDataType.h>
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#include <react/renderer/css/CSSLengthUnit.h>
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namespace facebook::react {
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/**
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* Representation of CSS <length> data type
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* https://www.w3.org/TR/css-values-4/#lengths
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*/
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struct CSSLength {
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float value{};
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CSSLengthUnit unit{CSSLengthUnit::Px};
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constexpr bool operator==(const CSSLength& rhs) const = default;
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};
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template <>
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struct CSSDataTypeParser<CSSLength> {
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static constexpr auto consumePreservedToken(const CSSPreservedToken& token)
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-> std::optional<CSSLength> {
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switch (token.type()) {
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case CSSTokenType::Dimension:
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if (auto unit = parseCSSLengthUnit(token.unit())) {
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return CSSLength{token.numericValue(), *unit};
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}
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break;
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case CSSTokenType::Number:
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// For zero lengths the unit identifier is optional (i.e. can be
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// syntactically represented as the <number> 0). However, if a 0
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// could be parsed as either a <number> or a <length> in a
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// property (such as line-height), it must parse as a <number>.
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// https://www.w3.org/TR/css-values-4/#lengths
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if (token.numericValue() == 0) {
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return CSSLength{token.numericValue(), CSSLengthUnit::Px};
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}
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break;
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default:
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break;
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}
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return {};
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}
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};
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static_assert(CSSDataType<CSSLength>);
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} // namespace facebook::react
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