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/*
* Copyright (C) 2025 Samuel Weinig <sam@webkit.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <WebCore/StylePrimitiveNumeric.h>
namespace WebCore {
class RenderStyle;
class StyleBoxData;
namespace Style {
// <'z-index'> = auto | <integer>
// https://drafts.csswg.org/css2/#propdef-z-index
struct ZIndex {
using Value = Integer<>;
constexpr ZIndex(CSS::Keyword::Auto)
{
}
constexpr ZIndex(Value value)
: m_isAuto { false }
, m_value { value }
{
}
constexpr ZIndex(Value::ResolvedValueType value)
: m_isAuto { false }
, m_value { value }
{
}
constexpr ZIndex(CSS::ValueLiteral<CSS::IntegerUnit::Integer> literal)
: m_isAuto { false }
, m_value { literal }
{
}
constexpr bool isAuto() const { return m_isAuto; }
constexpr bool isValue() const { return !m_isAuto; }
constexpr std::optional<Value> tryValue() const { return isValue() ? std::make_optional(m_value) : std::nullopt; }
template<typename... F> decltype(auto) switchOn(F&&... f) const
{
auto visitor = WTF::makeVisitor(std::forward<F>(f)...);
if (m_isAuto)
return visitor(CSS::Keyword::Auto { });
return visitor(m_value);
}
constexpr bool operator==(const ZIndex&) const = default;
private:
// NOTE: This type is stored represented using an explicit `bool` and `Value`, rather than a `Variant`, to allow compact
// storage and efficient construction in `StyleBoxData`. It is not using a `ValueOrKeyword` to preserve the entire `int`
// value range for `z-index`. If we determine its ok for `z-index` to only have `MAX_INT - 1` values, we can switch this
// out for `ValueOrKeyword` with a custom `MarkableTraits`.
friend class WebCore::RenderStyle;
friend class WebCore::StyleBoxData;
constexpr ZIndex(bool isAuto, Value value)
: m_isAuto { isAuto }
, m_value { value }
{
}
bool m_isAuto { true };
Value m_value { 0 };
};
// MARK: - Conversion
template<> struct CSSValueConversion<ZIndex> { auto operator()(BuilderState&, const CSSValue&) -> ZIndex; };
// MARK: - Blending
template<> struct Blending<ZIndex> {
auto canBlend(const ZIndex&, const ZIndex&) -> bool;
auto blend(const ZIndex&, const ZIndex&, const BlendingContext&) -> ZIndex;
};
} // namespace Style
} // namespace WebCore
DEFINE_VARIANT_LIKE_CONFORMANCE(WebCore::Style::ZIndex)
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