LibWeb: Port Selector to new Strings

Also use `Infra::is_ascii_case_insensitive_match()` in some appropriate
places, after checking the specs.

Userland/Libraries/LibWeb/CSS/CSSStyleRule.cpp

@@ -51,7 +51,7 @@ DeprecatedString CSSStyleRule::serialized() const
 
     // 1. Let s initially be the result of performing serialize a group of selectors on the rule’s associated selectors,
     //    followed by the string " {", i.e., a single SPACE (U+0020), followed by LEFT CURLY BRACKET (U+007B).
-    builder.append(serialize_a_group_of_selectors(selectors()));
+    builder.append(serialize_a_group_of_selectors(selectors()).release_value_but_fixme_should_propagate_errors());
     builder.append(" {"sv);
 
     // 2. Let decls be the result of performing serialize a CSS declaration block on the rule’s associated declarations, or null if there are no such declarations.
@@ -92,7 +92,7 @@ DeprecatedString CSSStyleRule::serialized() const
 DeprecatedString CSSStyleRule::selector_text() const
 {
     // The selectorText attribute, on getting, must return the result of serializing the associated group of selectors.
-    return serialize_a_group_of_selectors(selectors());
+    return serialize_a_group_of_selectors(selectors()).release_value_but_fixme_should_propagate_errors().to_deprecated_string();
 }
 
 // https://www.w3.org/TR/cssom/#dom-cssstylerule-selectortext

Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -280,7 +280,7 @@ Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_attribute_simple_se
             // they are converted to lowercase, so we do that here too. If we want to be
             // correct with XML later, we'll need to keep the original case and then do
             // a case-insensitive compare later.
-            .name = attribute_part.token().ident().to_lowercase_string(),
+            .name = FlyString::from_utf8(attribute_part.token().ident().to_lowercase_string()).release_value_but_fixme_should_propagate_errors(),
             .case_type = Selector::SimpleSelector::Attribute::CaseType::DefaultMatch,
         }
     };
@@ -340,7 +340,8 @@ Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_attribute_simple_se
         dbgln_if(CSS_PARSER_DEBUG, "Expected a string or ident for the value to match attribute against, got: '{}'", value_part.to_debug_string());
         return ParseError::SyntaxError;
     }
-    simple_selector.attribute().value = value_part.token().is(Token::Type::Ident) ? value_part.token().ident() : value_part.token().string();
+    auto value_string_view = value_part.token().is(Token::Type::Ident) ? value_part.token().ident() : value_part.token().string();
+    simple_selector.attribute().value = String::from_utf8(value_string_view).release_value_but_fixme_should_propagate_errors();
 
     attribute_tokens.skip_whitespace();
     // Handle case-sensitivity suffixes. https://www.w3.org/TR/selectors-4/#attribute-case
@@ -563,8 +564,8 @@ Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_pseudo_simple_selec
                 return ParseError::SyntaxError;
             }
             // FIXME: Support multiple, comma-separated, language ranges.
-            Vector<DeprecatedFlyString> languages;
+            Vector<FlyString> languages;
-            languages.append(pseudo_function.values().first().token().to_string().release_value_but_fixme_should_propagate_errors().to_deprecated_string());
+            languages.append(pseudo_function.values().first().token().to_string().release_value_but_fixme_should_propagate_errors());
             return Selector::SimpleSelector {
                 .type = Selector::SimpleSelector::Type::PseudoClass,
                 .value = Selector::SimpleSelector::PseudoClass {
@@ -618,7 +619,7 @@ Parser::ParseErrorOr<Optional<Selector::SimpleSelector>> Parser::parse_simple_se
             }
             return Selector::SimpleSelector {
                 .type = Selector::SimpleSelector::Type::Class,
-                .value = Selector::SimpleSelector::Name { class_name_value.token().ident() }
+                .value = Selector::SimpleSelector::Name { FlyString::from_utf8(class_name_value.token().ident()).release_value_but_fixme_should_propagate_errors() }
             };
         }
         case '>':
@@ -642,13 +643,13 @@ Parser::ParseErrorOr<Optional<Selector::SimpleSelector>> Parser::parse_simple_se
         }
         return Selector::SimpleSelector {
             .type = Selector::SimpleSelector::Type::Id,
-            .value = Selector::SimpleSelector::Name { first_value.token().hash_value() }
+            .value = Selector::SimpleSelector::Name { FlyString::from_utf8(first_value.token().hash_value()).release_value_but_fixme_should_propagate_errors() }
         };
     }
     if (first_value.is(Token::Type::Ident)) {
         return Selector::SimpleSelector {
             .type = Selector::SimpleSelector::Type::TagName,
-            .value = Selector::SimpleSelector::Name { first_value.token().ident() }
+            .value = Selector::SimpleSelector::Name { FlyString::from_utf8(first_value.token().ident()).release_value_but_fixme_should_propagate_errors() }
         };
     }
     if (first_value.is_block() && first_value.block().is_square())

Userland/Libraries/LibWeb/CSS/Selector.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
- * Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -119,7 +119,7 @@ u32 Selector::specificity() const
 }
 
 // https://www.w3.org/TR/cssom/#serialize-a-simple-selector
-DeprecatedString Selector::SimpleSelector::serialize() const
+ErrorOr<String> Selector::SimpleSelector::serialize() const
 {
     StringBuilder s;
     switch (type) {
@@ -129,50 +129,50 @@ DeprecatedString Selector::SimpleSelector::serialize() const
         // FIXME: 2. If the namespace prefix maps to a namespace that is the null namespace (not in a namespace) append "|" (U+007C) to s.
         // 3. If this is a type selector append the serialization of the element name as an identifier to s.
         if (type == Selector::SimpleSelector::Type::TagName) {
-            serialize_an_identifier(s, name()).release_value_but_fixme_should_propagate_errors();
+            TRY(serialize_an_identifier(s, name()));
         }
         // 4. If this is a universal selector append "*" (U+002A) to s.
         if (type == Selector::SimpleSelector::Type::Universal)
-            s.append('*');
+            TRY(s.try_append('*'));
         break;
     case Selector::SimpleSelector::Type::Attribute: {
         auto& attribute = this->attribute();
 
         // 1. Append "[" (U+005B) to s.
-        s.append('[');
+        TRY(s.try_append('['));
 
         // FIXME: 2. If the namespace prefix maps to a namespace that is not the null namespace (not in a namespace) append the serialization of the namespace prefix as an identifier, followed by a "|" (U+007C) to s.
 
         // 3. Append the serialization of the attribute name as an identifier to s.
-        serialize_an_identifier(s, attribute.name).release_value_but_fixme_should_propagate_errors();
+        TRY(serialize_an_identifier(s, attribute.name));
 
         // 4. If there is an attribute value specified, append "=", "~=", "|=", "^=", "$=", or "*=" as appropriate (depending on the type of attribute selector),
         //    followed by the serialization of the attribute value as a string, to s.
-        if (!attribute.value.is_null()) {
+        if (!attribute.value.is_empty()) {
             switch (attribute.match_type) {
             case Selector::SimpleSelector::Attribute::MatchType::ExactValueMatch:
-                s.append("="sv);
+                TRY(s.try_append("="sv));
                 break;
             case Selector::SimpleSelector::Attribute::MatchType::ContainsWord:
-                s.append("~="sv);
+                TRY(s.try_append("~="sv));
                 break;
             case Selector::SimpleSelector::Attribute::MatchType::ContainsString:
-                s.append("*="sv);
+                TRY(s.try_append("*="sv));
                 break;
             case Selector::SimpleSelector::Attribute::MatchType::StartsWithSegment:
-                s.append("|="sv);
+                TRY(s.try_append("|="sv));
                 break;
             case Selector::SimpleSelector::Attribute::MatchType::StartsWithString:
-                s.append("^="sv);
+                TRY(s.try_append("^="sv));
                 break;
             case Selector::SimpleSelector::Attribute::MatchType::EndsWithString:
-                s.append("$="sv);
+                TRY(s.try_append("$="sv));
                 break;
             default:
                 break;
             }
 
-            serialize_a_string(s, attribute.value).release_value_but_fixme_should_propagate_errors();
+            TRY(serialize_a_string(s, attribute.value));
         }
 
         // 5. If the attribute selector has the case-insensitivity flag present, append " i" (U+0020 U+0069) to s.
@@ -180,30 +180,30 @@ DeprecatedString Selector::SimpleSelector::serialize() const
         //    (the line just above is an addition to CSS OM to match Selectors Level 4 last draft)
         switch (attribute.case_type) {
         case Selector::SimpleSelector::Attribute::CaseType::CaseInsensitiveMatch:
-            s.append(" i"sv);
+            TRY(s.try_append(" i"sv));
             break;
         case Selector::SimpleSelector::Attribute::CaseType::CaseSensitiveMatch:
-            s.append(" s"sv);
+            TRY(s.try_append(" s"sv));
             break;
         default:
             break;
         }
 
         // 6. Append "]" (U+005D) to s.
-        s.append(']');
+        TRY(s.try_append(']'));
         break;
     }
 
     case Selector::SimpleSelector::Type::Class:
         // Append a "." (U+002E), followed by the serialization of the class name as an identifier to s.
-        s.append('.');
+        TRY(s.try_append('.'));
-        serialize_an_identifier(s, name()).release_value_but_fixme_should_propagate_errors();
+        TRY(serialize_an_identifier(s, name()));
         break;
 
     case Selector::SimpleSelector::Type::Id:
         // Append a "#" (U+0023), followed by the serialization of the ID as an identifier to s.
-        s.append('#');
+        TRY(s.try_append('#'));
-        serialize_an_identifier(s, name()).release_value_but_fixme_should_propagate_errors();
+        TRY(serialize_an_identifier(s, name()));
         break;
 
     case Selector::SimpleSelector::Type::PseudoClass: {
@@ -228,8 +228,8 @@ DeprecatedString Selector::SimpleSelector::serialize() const
         case Selector::SimpleSelector::PseudoClass::Type::Checked:
         case Selector::SimpleSelector::PseudoClass::Type::Active:
             // If the pseudo-class does not accept arguments append ":" (U+003A), followed by the name of the pseudo-class, to s.
-            s.append(':');
+            TRY(s.try_append(':'));
-            s.append(pseudo_class_name(pseudo_class.type));
+            TRY(s.try_append(pseudo_class_name(pseudo_class.type)));
             break;
         case Selector::SimpleSelector::PseudoClass::Type::NthChild:
         case Selector::SimpleSelector::PseudoClass::Type::NthLastChild:
@@ -241,26 +241,26 @@ DeprecatedString Selector::SimpleSelector::serialize() const
         case Selector::SimpleSelector::PseudoClass::Type::Lang:
             // Otherwise, append ":" (U+003A), followed by the name of the pseudo-class, followed by "(" (U+0028),
             // followed by the value of the pseudo-class argument(s) determined as per below, followed by ")" (U+0029), to s.
-            s.append(':');
+            TRY(s.try_append(':'));
-            s.append(pseudo_class_name(pseudo_class.type));
+            TRY(s.try_append(pseudo_class_name(pseudo_class.type)));
-            s.append('(');
+            TRY(s.try_append('('));
             if (pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::NthChild
                 || pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::NthLastChild
                 || pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::NthOfType
                 || pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::NthLastOfType) {
                 // The result of serializing the value using the rules to serialize an <an+b> value.
-                s.append(pseudo_class.nth_child_pattern.serialize());
+                TRY(s.try_append(TRY(pseudo_class.nth_child_pattern.serialize())));
             } else if (pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::Not
                 || pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::Is
                 || pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::Where) {
                 // The result of serializing the value using the rules for serializing a group of selectors.
                 // NOTE: `:is()` and `:where()` aren't in the spec for this yet, but it should be!
-                s.append(serialize_a_group_of_selectors(pseudo_class.argument_selector_list));
+                TRY(s.try_append(TRY(serialize_a_group_of_selectors(pseudo_class.argument_selector_list))));
             } else if (pseudo_class.type == Selector::SimpleSelector::PseudoClass::Type::Lang) {
                 // The serialization of a comma-separated list of each argument’s serialization as a string, preserving relative order.
                 s.join(", "sv, pseudo_class.languages);
             }
-            s.append(')');
+            TRY(s.try_append(')'));
             break;
         default:
             dbgln("FIXME: Unknown pseudo class type for serialization: {}", to_underlying(pseudo_class.type));
@@ -275,11 +275,11 @@ DeprecatedString Selector::SimpleSelector::serialize() const
         dbgln("FIXME: Unsupported simple selector serialization for type {}", to_underlying(type));
         break;
     }
-    return s.to_deprecated_string();
+    return s.to_string();
 }
 
 // https://www.w3.org/TR/cssom/#serialize-a-selector
-DeprecatedString Selector::serialize() const
+ErrorOr<String> Selector::serialize() const
 {
     StringBuilder s;
 
@@ -289,14 +289,14 @@ DeprecatedString Selector::serialize() const
         // 1. If there is only one simple selector in the compound selectors which is a universal selector, append the result of serializing the universal selector to s.
         if (compound_selector.simple_selectors.size() == 1
             && compound_selector.simple_selectors.first().type == Selector::SimpleSelector::Type::Universal) {
-            s.append(compound_selector.simple_selectors.first().serialize());
+            TRY(s.try_append(TRY(compound_selector.simple_selectors.first().serialize())));
         }
         // 2. Otherwise, for each simple selector in the compound selectors...
         //    FIXME: ...that is not a universal selector of which the namespace prefix maps to a namespace that is not the default namespace...
         //    ...serialize the simple selector and append the result to s.
         else {
             for (auto& simple_selector : compound_selector.simple_selectors) {
-                s.append(simple_selector.serialize());
+                TRY(s.try_append(TRY(simple_selector.serialize())));
             }
         }
 
@@ -304,21 +304,21 @@ DeprecatedString Selector::serialize() const
         //    followed by the combinator ">", "+", "~", ">>", "||", as appropriate, followed by another
         //    single SPACE (U+0020) if the combinator was not whitespace, to s.
         if (i != compound_selectors().size() - 1) {
-            s.append(' ');
+            TRY(s.try_append(' '));
             // Note: The combinator that appears between parts `i` and `i+1` appears with the `i+1` selector,
             //       so we have to check that one.
             switch (compound_selectors()[i + 1].combinator) {
             case Selector::Combinator::ImmediateChild:
-                s.append("> "sv);
+                TRY(s.try_append("> "sv));
                 break;
             case Selector::Combinator::NextSibling:
-                s.append("+ "sv);
+                TRY(s.try_append("+ "sv));
                 break;
             case Selector::Combinator::SubsequentSibling:
-                s.append("~ "sv);
+                TRY(s.try_append("~ "sv));
                 break;
             case Selector::Combinator::Column:
-                s.append("|| "sv);
+                TRY(s.try_append("|| "sv));
                 break;
             default:
                 break;
@@ -327,22 +327,20 @@ DeprecatedString Selector::serialize() const
             // 4. If this is the last part of the chain of the selector and there is a pseudo-element,
             // append "::" followed by the name of the pseudo-element, to s.
             if (compound_selector.simple_selectors.last().type == Selector::SimpleSelector::Type::PseudoElement) {
-                s.append("::"sv);
+                TRY(s.try_append("::"sv));
-                s.append(pseudo_element_name(compound_selector.simple_selectors.last().pseudo_element()));
+                TRY(s.try_append(pseudo_element_name(compound_selector.simple_selectors.last().pseudo_element())));
             }
         }
     }
 
-    return s.to_deprecated_string();
+    return s.to_string();
 }
 
 // https://www.w3.org/TR/cssom/#serialize-a-group-of-selectors
-DeprecatedString serialize_a_group_of_selectors(NonnullRefPtrVector<Selector> const& selectors)
+ErrorOr<String> serialize_a_group_of_selectors(NonnullRefPtrVector<Selector> const& selectors)
 {
     // To serialize a group of selectors serialize each selector in the group of selectors and then serialize a comma-separated list of these serializations.
-    StringBuilder builder;
+    return String::join(", "sv, selectors);
-    builder.join(", "sv, selectors);
-    return builder.to_deprecated_string();
 }
 
 Optional<Selector::PseudoElement> pseudo_element_from_string(StringView name)

Userland/Libraries/LibWeb/CSS/Selector.h

@@ -7,10 +7,10 @@
 
 #pragma once
 
-#include <AK/DeprecatedFlyString.h>
+#include <AK/FlyString.h>
-#include <AK/DeprecatedString.h>
 #include <AK/NonnullRefPtrVector.h>
 #include <AK/RefCounted.h>
+#include <AK/String.h>
 #include <AK/Vector.h>
 
 namespace Web::CSS {
@@ -50,11 +50,11 @@ public:
             int offset = { 0 };  // "B"
 
             // https://www.w3.org/TR/css-syntax-3/#serializing-anb
-            DeprecatedString serialize() const
+            ErrorOr<String> serialize() const
             {
                 // 1. If A is zero, return the serialization of B.
                 if (step_size == 0) {
-                    return DeprecatedString::formatted("{}", offset);
+                    return String::formatted("{}", offset);
                 }
 
                 // 2. Otherwise, let result initially be an empty string.
@@ -63,24 +63,24 @@ public:
                 // 3.
                 // - A is 1: Append "n" to result.
                 if (step_size == 1)
-                    result.append('n');
+                    TRY(result.try_append('n'));
                 // - A is -1: Append "-n" to result.
                 else if (step_size == -1)
-                    result.append("-n"sv);
+                    TRY(result.try_append("-n"sv));
                 // - A is non-zero: Serialize A and append it to result, then append "n" to result.
                 else if (step_size != 0)
-                    result.appendff("{}n", step_size);
+                    TRY(result.try_appendff("{}n", step_size));
 
                 // 4.
                 // - B is greater than zero: Append "+" to result, then append the serialization of B to result.
                 if (offset > 0)
-                    result.appendff("+{}", offset);
+                    TRY(result.try_appendff("+{}", offset));
                 // - B is less than zero: Append the serialization of B to result.
                 if (offset < 0)
-                    result.appendff("{}", offset);
+                    TRY(result.try_appendff("{}", offset));
 
                 // 5. Return result.
-                return result.to_deprecated_string();
+                return result.to_string();
             }
         };
 
@@ -121,7 +121,7 @@ public:
             SelectorList argument_selector_list {};
 
             // Used for :lang(en-gb,dk)
-            Vector<DeprecatedFlyString> languages {};
+            Vector<FlyString> languages {};
         };
 
         struct Attribute {
@@ -140,20 +140,20 @@ public:
                 CaseInsensitiveMatch,
             };
             MatchType match_type;
-            DeprecatedFlyString name {};
+            FlyString name {};
-            DeprecatedString value {};
+            String value {};
             CaseType case_type;
         };
 
         struct Name {
-            Name(DeprecatedFlyString n)
+            Name(FlyString n)
                 : name(move(n))
-                , lowercase_name(name.to_lowercase())
+                , lowercase_name(name.to_string().to_lowercase().release_value_but_fixme_should_propagate_errors())
             {
             }
 
-            DeprecatedFlyString name;
+            FlyString name;
-            DeprecatedFlyString lowercase_name;
+            FlyString lowercase_name;
         };
 
         Type type;
@@ -166,12 +166,12 @@ public:
         PseudoElement const& pseudo_element() const { return value.get<PseudoElement>(); }
         PseudoElement& pseudo_element() { return value.get<PseudoElement>(); }
 
-        DeprecatedFlyString const& name() const { return value.get<Name>().name; }
+        FlyString const& name() const { return value.get<Name>().name; }
-        DeprecatedFlyString& name() { return value.get<Name>().name; }
+        FlyString& name() { return value.get<Name>().name; }
-        DeprecatedFlyString const& lowercase_name() const { return value.get<Name>().lowercase_name; }
+        FlyString const& lowercase_name() const { return value.get<Name>().lowercase_name; }
-        DeprecatedFlyString& lowercase_name() { return value.get<Name>().lowercase_name; }
+        FlyString& lowercase_name() { return value.get<Name>().lowercase_name; }
 
-        DeprecatedString serialize() const;
+        ErrorOr<String> serialize() const;
     };
 
     enum class Combinator {
@@ -200,7 +200,7 @@ public:
     Vector<CompoundSelector> const& compound_selectors() const { return m_compound_selectors; }
     Optional<PseudoElement> pseudo_element() const { return m_pseudo_element; }
     u32 specificity() const;
-    DeprecatedString serialize() const;
+    ErrorOr<String> serialize() const;
 
 private:
     explicit Selector(Vector<CompoundSelector>&&);
@@ -294,7 +294,7 @@ constexpr StringView pseudo_class_name(Selector::SimpleSelector::PseudoClass::Ty
     VERIFY_NOT_REACHED();
 }
 
-DeprecatedString serialize_a_group_of_selectors(NonnullRefPtrVector<Selector> const& selectors);
+ErrorOr<String> serialize_a_group_of_selectors(NonnullRefPtrVector<Selector> const& selectors);
 
 }
 
@@ -304,7 +304,7 @@ template<>
 struct Formatter<Web::CSS::Selector> : Formatter<StringView> {
     ErrorOr<void> format(FormatBuilder& builder, Web::CSS::Selector const& selector)
     {
-        return Formatter<StringView>::format(builder, selector.serialize());
+        return Formatter<StringView>::format(builder, TRY(selector.serialize()));
     }
 };
 

Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
- * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -21,21 +21,22 @@
 #include <LibWeb/HTML/HTMLOptionElement.h>
 #include <LibWeb/HTML/HTMLSelectElement.h>
 #include <LibWeb/HTML/HTMLTextAreaElement.h>
+#include <LibWeb/Infra/Strings.h>
 
 namespace Web::SelectorEngine {
 
 // https://drafts.csswg.org/selectors-4/#the-lang-pseudo
-static inline bool matches_lang_pseudo_class(DOM::Element const& element, Vector<DeprecatedFlyString> const& languages)
+static inline bool matches_lang_pseudo_class(DOM::Element const& element, Vector<FlyString> const& languages)
 {
-    DeprecatedFlyString element_language;
+    FlyString element_language;
     for (auto const* e = &element; e; e = e->parent_element()) {
         auto lang = e->attribute(HTML::AttributeNames::lang);
         if (!lang.is_null()) {
-            element_language = lang;
+            element_language = FlyString::from_utf8(lang).release_value_but_fixme_should_propagate_errors();
             break;
         }
     }
-    if (element_language.is_null())
+    if (element_language.is_empty())
         return false;
 
     // FIXME: This is ad-hoc. Implement a proper language range matching algorithm as recommended by BCP47.
@@ -44,10 +45,10 @@ static inline bool matches_lang_pseudo_class(DOM::Element const& element, Vector
             return false;
         if (language == "*"sv)
             return true;
-        if (!element_language.view().contains('-'))
+        if (!element_language.to_string().contains('-'))
-            return element_language.equals_ignoring_case(language);
+            return Infra::is_ascii_case_insensitive_match(element_language, language);
-        auto parts = element_language.view().split_view('-');
+        auto parts = element_language.to_string().split_limit('-', 2).release_value_but_fixme_should_propagate_errors();
-        return parts[0].equals_ignoring_case(language);
+        return Infra::is_ascii_case_insensitive_match(parts[0], language);
     }
     return false;
 }
@@ -97,7 +98,7 @@ static inline bool matches_attribute(CSS::Selector::SimpleSelector::Attribute co
 {
     if (attribute.match_type == CSS::Selector::SimpleSelector::Attribute::MatchType::HasAttribute) {
         // Early way out in case of an attribute existence selector.
-        return element.has_attribute(attribute.name);
+        return element.has_attribute(attribute.name.to_string().to_deprecated_string());
     }
 
     auto const case_insensitive_match = (attribute.case_type == CSS::Selector::SimpleSelector::Attribute::CaseType::CaseInsensitiveMatch);
@@ -108,19 +109,19 @@ static inline bool matches_attribute(CSS::Selector::SimpleSelector::Attribute co
     switch (attribute.match_type) {
     case CSS::Selector::SimpleSelector::Attribute::MatchType::ExactValueMatch:
         return case_insensitive_match
-            ? element.attribute(attribute.name).equals_ignoring_case(attribute.value)
+            ? Infra::is_ascii_case_insensitive_match(element.attribute(attribute.name.to_string().to_deprecated_string()), attribute.value)
-            : element.attribute(attribute.name) == attribute.value;
+            : element.attribute(attribute.name.to_string().to_deprecated_string()) == attribute.value.to_deprecated_string();
     case CSS::Selector::SimpleSelector::Attribute::MatchType::ContainsWord: {
         if (attribute.value.is_empty()) {
             // This selector is always false is match value is empty.
             return false;
         }
-        auto const view = element.attribute(attribute.name).split_view(' ');
+        auto const view = element.attribute(attribute.name.to_string().to_deprecated_string()).split_view(' ');
         auto const size = view.size();
         for (size_t i = 0; i < size; ++i) {
             auto const value = view.at(i);
             if (case_insensitive_match
-                    ? value.equals_ignoring_case(attribute.value)
+                    ? Infra::is_ascii_case_insensitive_match(value, attribute.value)
                     : value == attribute.value) {
                 return true;
             }
@@ -129,9 +130,9 @@ static inline bool matches_attribute(CSS::Selector::SimpleSelector::Attribute co
     }
     case CSS::Selector::SimpleSelector::Attribute::MatchType::ContainsString:
         return !attribute.value.is_empty()
-            && element.attribute(attribute.name).contains(attribute.value, case_sensitivity);
+            && element.attribute(attribute.name.to_string().to_deprecated_string()).contains(attribute.value, case_sensitivity);
     case CSS::Selector::SimpleSelector::Attribute::MatchType::StartsWithSegment: {
-        auto const element_attr_value = element.attribute(attribute.name);
+        auto const element_attr_value = element.attribute(attribute.name.to_string().to_deprecated_string());
         if (element_attr_value.is_empty()) {
             // If the attribute value on element is empty, the selector is true
             // if the match value is also empty and false otherwise.
@@ -142,15 +143,15 @@ static inline bool matches_attribute(CSS::Selector::SimpleSelector::Attribute co
         }
         auto segments = element_attr_value.split_view('-');
         return case_insensitive_match
-            ? segments.first().equals_ignoring_case(attribute.value)
+            ? Infra::is_ascii_case_insensitive_match(segments.first(), attribute.value)
             : segments.first() == attribute.value;
     }
     case CSS::Selector::SimpleSelector::Attribute::MatchType::StartsWithString:
         return !attribute.value.is_empty()
-            && element.attribute(attribute.name).starts_with(attribute.value, case_sensitivity);
+            && element.attribute(attribute.name.to_string().to_deprecated_string()).starts_with(attribute.value, case_sensitivity);
     case CSS::Selector::SimpleSelector::Attribute::MatchType::EndsWithString:
         return !attribute.value.is_empty()
-            && element.attribute(attribute.name).ends_with(attribute.value, case_sensitivity);
+            && element.attribute(attribute.name.to_string().to_deprecated_string()).ends_with(attribute.value, case_sensitivity);
     default:
         break;
     }
@@ -351,14 +352,14 @@ static inline bool matches(CSS::Selector::SimpleSelector const& component, DOM::
     case CSS::Selector::SimpleSelector::Type::Universal:
         return true;
     case CSS::Selector::SimpleSelector::Type::Id:
-        return component.name() == element.attribute(HTML::AttributeNames::id);
+        return component.name() == element.attribute(HTML::AttributeNames::id).view();
     case CSS::Selector::SimpleSelector::Type::Class:
-        return element.has_class(component.name());
+        return element.has_class(component.name().bytes_as_string_view());
     case CSS::Selector::SimpleSelector::Type::TagName:
         // See https://html.spec.whatwg.org/multipage/semantics-other.html#case-sensitivity-of-selectors
         if (element.document().document_type() == DOM::Document::Type::HTML)
-            return component.lowercase_name() == element.local_name();
+            return component.lowercase_name() == element.local_name().view();
-        return component.name().equals_ignoring_case(element.local_name());
+        return Infra::is_ascii_case_insensitive_match(component.name(), element.local_name());
     case CSS::Selector::SimpleSelector::Type::Attribute:
         return matches_attribute(component.attribute(), element);
     case CSS::Selector::SimpleSelector::Type::PseudoClass:

Userland/Libraries/LibWeb/CSS/StyleComputer.cpp

@@ -1469,19 +1469,19 @@ void StyleComputer::build_rule_cache()
                 if (!added_to_bucket) {
                     for (auto const& simple_selector : selector.compound_selectors().last().simple_selectors) {
                         if (simple_selector.type == CSS::Selector::SimpleSelector::Type::Id) {
-                            m_rule_cache->rules_by_id.ensure(simple_selector.name()).append(move(matching_rule));
+                            m_rule_cache->rules_by_id.ensure(simple_selector.name().to_string().to_deprecated_string()).append(move(matching_rule));
                             ++num_id_rules;
                             added_to_bucket = true;
                             break;
                         }
                         if (simple_selector.type == CSS::Selector::SimpleSelector::Type::Class) {
-                            m_rule_cache->rules_by_class.ensure(simple_selector.name()).append(move(matching_rule));
+                            m_rule_cache->rules_by_class.ensure(simple_selector.name().to_string().to_deprecated_string()).append(move(matching_rule));
                             ++num_class_rules;
                             added_to_bucket = true;
                             break;
                         }
                         if (simple_selector.type == CSS::Selector::SimpleSelector::Type::TagName) {
-                            m_rule_cache->rules_by_tag_name.ensure(simple_selector.name()).append(move(matching_rule));
+                            m_rule_cache->rules_by_tag_name.ensure(simple_selector.name().to_string().to_deprecated_string()).append(move(matching_rule));
                             ++num_tag_name_rules;
                             added_to_bucket = true;
                             break;