ladybird/Libraries/LibWeb/CSS/CSSStyleValue.cpp
Andreas Kling 26b0801a78 LibWeb: Return Utf16String from CSS Typed OM serialization
Make CSS Typed OM to_string() implementations produce Utf16String
instead of building UTF-8 strings and converting at the JS binding
boundary. Use Utf16StringBuilder for numeric, math, and transform
serialization paths that already feed CSS Typed OM stringification.

Keep the older CSSOM StyleValue serializer on StringBuilder for now, and
convert only where Typed OM source values or parser re-entry still need
the existing UTF-8 representation.
2026-06-22 16:10:40 +02:00

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/*
* Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "CSSStyleValue.h"
#include <LibWeb/Bindings/CSSStyleValue.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/CSS/Parser/Parser.h>
#include <LibWeb/CSS/PropertyNameAndID.h>
#include <LibWeb/CSS/StyleValues/StyleValue.h>
#include <LibWeb/CSS/StyleValues/StyleValueList.h>
#include <LibWeb/WebIDL/ExceptionOr.h>
namespace Web::CSS {
GC_DEFINE_ALLOCATOR(CSSStyleValue);
GC::Ref<CSSStyleValue> CSSStyleValue::create(JS::Realm& realm, Utf16FlyString associated_property, NonnullRefPtr<StyleValue const> source_value)
{
return realm.create<CSSStyleValue>(realm, move(associated_property), move(source_value));
}
CSSStyleValue::CSSStyleValue(JS::Realm& realm)
: PlatformObject(realm)
{
}
CSSStyleValue::CSSStyleValue(JS::Realm& realm, NonnullRefPtr<StyleValue const> source_value)
: PlatformObject(realm)
, m_source_value(move(source_value))
{
}
CSSStyleValue::CSSStyleValue(JS::Realm& realm, Utf16FlyString associated_property, NonnullRefPtr<StyleValue const> source_value)
: PlatformObject(realm)
, m_associated_property(move(associated_property))
, m_source_value(move(source_value))
{
}
void CSSStyleValue::initialize(JS::Realm& realm)
{
WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSStyleValue);
Base::initialize(realm);
}
CSSStyleValue::~CSSStyleValue() = default;
// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssstylevalue-parse
WebIDL::ExceptionOr<GC::Ref<CSSStyleValue>> CSSStyleValue::parse(JS::VM& vm, Utf16FlyString const& property, String css_text)
{
// The parse(property, cssText) method, when invoked, must parse a CSSStyleValue with property property, cssText
// cssText, and parseMultiple set to false, and return the result.
auto result = parse_a_css_style_value(vm, property, css_text, ParseMultiple::No);
if (result.is_exception())
return result.release_error();
return result.value().get<GC::Ref<CSSStyleValue>>();
}
// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssstylevalue-parseall
WebIDL::ExceptionOr<GC::RootVector<GC::Ref<CSSStyleValue>>> CSSStyleValue::parse_all(JS::VM& vm, Utf16FlyString const& property, String css_text)
{
// The parseAll(property, cssText) method, when invoked, must parse a CSSStyleValue with property property, cssText
// cssText, and parseMultiple set to true, and return the result.
auto result = parse_a_css_style_value(vm, property, css_text, ParseMultiple::Yes);
if (result.is_exception())
return result.release_error();
return result.value().get<GC::RootVector<GC::Ref<CSSStyleValue>>>();
}
// https://drafts.css-houdini.org/css-typed-om-1/#parse-a-cssstylevalue
WebIDL::ExceptionOr<Variant<GC::Ref<CSSStyleValue>, GC::RootVector<GC::Ref<CSSStyleValue>>>> CSSStyleValue::parse_a_css_style_value(JS::VM& vm, Utf16FlyString property_name, String css_text, ParseMultiple parse_multiple)
{
// 1. If property is not a custom property name string, set property to property ASCII lowercased.
// 2. If property is not a valid CSS property, throw a TypeError.
auto property = PropertyNameAndID::from_name(property_name);
if (!property.has_value())
return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, MUST(String::formatted("'{}' is not a valid CSS property", property_name)) };
// 3. Attempt to parse cssText according to propertys grammar.
// If this fails, throw a TypeError.
// Otherwise, let whole value be the parsed result.
auto whole_value = parse_css_value(Parser::ParsingParams {}, css_text, property->id());
if (!whole_value)
return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, MUST(String::formatted("Failed to parse '{}' as a value for '{}' property", css_text, property->name())) };
// 4. Subdivide into iterations whole value, according to property, and let values be the result.
auto values = whole_value->subdivide_into_iterations(property.value());
// 5. For each value in values, replace it with the result of reifying value for property.
GC::RootVector<GC::Ref<CSSStyleValue>> reified_values;
for (auto const& value : values) {
reified_values.append(value->reify(*vm.current_realm(), property->name()));
}
// 6. If parseMultiple is false, return values[0]. Otherwise, return values.
// FIXME: We need to somehow store the source css_text on the returned CSSStyleValue.
// https://github.com/w3c/css-houdini-drafts/issues/1156
if (parse_multiple == ParseMultiple::No)
return reified_values.take_first();
return reified_values;
}
// https://drafts.css-houdini.org/css-typed-om-1/#stylevalue-serialization
WebIDL::ExceptionOr<Utf16String> CSSStyleValue::to_string() const
{
// FIXME: if the value was constructed from a USVString
// NB: Basically, if this was constructed with "parse a CSSStyleValue", regardless of what CSSStyleValue type it is now.
{
// the serialization is the USVString from which the value was constructed.
}
// otherwise, if the value was constructed using an IDL constructor
{
// the serialization is specified in the sections below.
// NB: This is handled by subclasses overriding this to_string() method.
}
// FIXME: otherwise, if the value was extracted from the CSSOM
// NB: For CSSStyleValue itself, we use the source value we were created from.
if (m_source_value)
return Utf16String::from_utf8_without_validation(m_source_value->to_string(SerializationMode::Normal));
{
// the serialization is specified in §6.7 Serialization from CSSOM Values below.
}
return Utf16String::from_utf8_without_validation(""sv);
}
// https://drafts.css-houdini.org/css-typed-om-1/#create-an-internal-representation
WebIDL::ExceptionOr<NonnullRefPtr<StyleValue const>> CSSStyleValue::create_an_internal_representation(PropertyNameAndID const&, PerformTypeCheck) const
{
// If value is a direct CSSStyleValue,
// Return values associated value.
if (!m_source_value)
return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, MUST(String::formatted("Missing {}::create_an_internal_representation() overload", class_name())) };
return NonnullRefPtr { *m_source_value };
}
}