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ladybird/Userland/Libraries/LibWeb/CSS/Parser/SelectorParsing.cpp
Sam Atkins 5b125811f1 LibWeb: Add support for pseudo-class functions that take an ident param 
This is prep work for `:dir()`, though other pseudo-classes may well use
it in the future too.
2023-08-21 13:51:56 +02:00

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/*
* Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020-2021, the SerenityOS developers.
* Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
* Copyright (c) 2022, MacDue <macdue@dueutil.tech>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <LibWeb/CSS/Parser/Parser.h>
namespace Web::CSS::Parser {
Optional<SelectorList> Parser::parse_as_selector(SelectorParsingMode parsing_mode)
{
auto selector_list = parse_a_selector_list(m_token_stream, SelectorType::Standalone, parsing_mode);
if (!selector_list.is_error())
return selector_list.release_value();
return {};
}
Optional<SelectorList> Parser::parse_as_relative_selector(SelectorParsingMode parsing_mode)
{
auto selector_list = parse_a_selector_list(m_token_stream, SelectorType::Relative, parsing_mode);
if (!selector_list.is_error())
return selector_list.release_value();
return {};
}
template<typename T>
Parser::ParseErrorOr<SelectorList> Parser::parse_a_selector_list(TokenStream<T>& tokens, SelectorType mode, SelectorParsingMode parsing_mode)
{
auto comma_separated_lists = parse_a_comma_separated_list_of_component_values(tokens);
Vector<NonnullRefPtr<Selector>> selectors;
for (auto& selector_parts : comma_separated_lists) {
auto stream = TokenStream(selector_parts);
auto selector = parse_complex_selector(stream, mode);
if (selector.is_error()) {
if (parsing_mode == SelectorParsingMode::Forgiving)
continue;
return selector.error();
}
selectors.append(selector.release_value());
}
if (selectors.is_empty() && parsing_mode != SelectorParsingMode::Forgiving)
return ParseError::SyntaxError;
return selectors;
}
template Parser::ParseErrorOr<SelectorList> Parser::parse_a_selector_list(TokenStream<ComponentValue>&, SelectorType, SelectorParsingMode);
template Parser::ParseErrorOr<SelectorList> Parser::parse_a_selector_list(TokenStream<Token>&, SelectorType, SelectorParsingMode);
Parser::ParseErrorOr<NonnullRefPtr<Selector>> Parser::parse_complex_selector(TokenStream<ComponentValue>& tokens, SelectorType mode)
{
Vector<Selector::CompoundSelector> compound_selectors;
auto first_selector = TRY(parse_compound_selector(tokens));
if (!first_selector.has_value())
return ParseError::SyntaxError;
if (mode == SelectorType::Standalone) {
if (first_selector->combinator != Selector::Combinator::Descendant)
return ParseError::SyntaxError;
first_selector->combinator = Selector::Combinator::None;
}
compound_selectors.append(first_selector.release_value());
while (tokens.has_next_token()) {
auto compound_selector = TRY(parse_compound_selector(tokens));
if (!compound_selector.has_value())
break;
compound_selectors.append(compound_selector.release_value());
}
if (compound_selectors.is_empty())
return ParseError::SyntaxError;
return Selector::create(move(compound_selectors));
}
Parser::ParseErrorOr<Optional<Selector::CompoundSelector>> Parser::parse_compound_selector(TokenStream<ComponentValue>& tokens)
{
tokens.skip_whitespace();
auto combinator = parse_selector_combinator(tokens).value_or(Selector::Combinator::Descendant);
tokens.skip_whitespace();
Vector<Selector::SimpleSelector> simple_selectors;
while (tokens.has_next_token()) {
auto component = TRY(parse_simple_selector(tokens));
if (!component.has_value())
break;
simple_selectors.append(component.release_value());
}
if (simple_selectors.is_empty())
return Optional<Selector::CompoundSelector> {};
return Selector::CompoundSelector { combinator, move(simple_selectors) };
}
Optional<Selector::Combinator> Parser::parse_selector_combinator(TokenStream<ComponentValue>& tokens)
{
auto const& current_value = tokens.next_token();
if (current_value.is(Token::Type::Delim)) {
switch (current_value.token().delim()) {
case '>':
return Selector::Combinator::ImmediateChild;
case '+':
return Selector::Combinator::NextSibling;
case '~':
return Selector::Combinator::SubsequentSibling;
case '|': {
auto const& next = tokens.peek_token();
if (next.is(Token::Type::EndOfFile))
return {};
if (next.is_delim('|')) {
tokens.next_token();
return Selector::Combinator::Column;
}
}
}
}
tokens.reconsume_current_input_token();
return {};
}
Optional<Selector::SimpleSelector::QualifiedName> Parser::parse_selector_qualified_name(TokenStream<ComponentValue>& tokens, AllowWildcardName allow_wildcard_name)
{
auto is_name = [](ComponentValue const& token) {
return token.is_delim('*') || token.is(Token::Type::Ident);
};
auto get_name = [](ComponentValue const& token) {
if (token.is_delim('*'))
return FlyString::from_utf8("*"sv);
return FlyString::from_utf8(token.token().ident());
};
// There are 3 possibilities here:
// (Where <name> and <namespace> are either an <ident> or a `*` delim)
// 1) `|<name>`
// 2) `<namespace>|<name>`
// 3) `<name>`
// Whitespace is forbidden between any of these parts. https://www.w3.org/TR/selectors-4/#white-space
auto transaction = tokens.begin_transaction();
auto first_token = tokens.next_token();
if (first_token.is_delim('|')) {
// Case 1: `|<name>`
if (is_name(tokens.peek_token())) {
auto name_token = tokens.next_token();
if (allow_wildcard_name == AllowWildcardName::No && name_token.is_delim('*'))
return {};
transaction.commit();
return Selector::SimpleSelector::QualifiedName {
.namespace_type = Selector::SimpleSelector::QualifiedName::NamespaceType::None,
.name = get_name(name_token).release_value_but_fixme_should_propagate_errors(),
};
}
return {};
}
if (!is_name(first_token))
return {};
if (tokens.peek_token().is_delim('|') && is_name(tokens.peek_token(1))) {
// Case 2: `<namespace>|<name>`
(void)tokens.next_token(); // `|`
auto namespace_ = get_name(first_token).release_value_but_fixme_should_propagate_errors();
auto name = get_name(tokens.next_token()).release_value_but_fixme_should_propagate_errors();
if (allow_wildcard_name == AllowWildcardName::No && name == "*"sv)
return {};
auto namespace_type = namespace_ == "*"sv
? Selector::SimpleSelector::QualifiedName::NamespaceType::Any
: Selector::SimpleSelector::QualifiedName::NamespaceType::Named;
transaction.commit();
return Selector::SimpleSelector::QualifiedName {
.namespace_type = namespace_type,
.namespace_ = namespace_,
.name = name,
};
}
// Case 3: `<name>`
auto& name_token = first_token;
if (allow_wildcard_name == AllowWildcardName::No && name_token.is_delim('*'))
return {};
transaction.commit();
return Selector::SimpleSelector::QualifiedName {
.namespace_type = Selector::SimpleSelector::QualifiedName::NamespaceType::Default,
.name = get_name(name_token).release_value_but_fixme_should_propagate_errors(),
};
}
Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_attribute_simple_selector(ComponentValue const& first_value)
{
auto attribute_tokens = TokenStream { first_value.block().values() };
attribute_tokens.skip_whitespace();
if (!attribute_tokens.has_next_token()) {
dbgln_if(CSS_PARSER_DEBUG, "CSS attribute selector is empty!");
return ParseError::SyntaxError;
}
auto maybe_qualified_name = parse_selector_qualified_name(attribute_tokens, AllowWildcardName::No);
if (!maybe_qualified_name.has_value()) {
dbgln_if(CSS_PARSER_DEBUG, "Expected qualified-name for attribute name, got: '{}'", attribute_tokens.peek_token().to_debug_string());
return ParseError::SyntaxError;
}
Selector::SimpleSelector simple_selector {
.type = Selector::SimpleSelector::Type::Attribute,
.value = Selector::SimpleSelector::Attribute {
.match_type = Selector::SimpleSelector::Attribute::MatchType::HasAttribute,
// FIXME: Case-sensitivity is defined by the document language.
// HTML is insensitive with attribute names, and our code generally assumes
// 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.
.qualified_name = maybe_qualified_name.release_value(),
.case_type = Selector::SimpleSelector::Attribute::CaseType::DefaultMatch,
}
};
attribute_tokens.skip_whitespace();
if (!attribute_tokens.has_next_token())
return simple_selector;
auto const& delim_part = attribute_tokens.next_token();
if (!delim_part.is(Token::Type::Delim)) {
dbgln_if(CSS_PARSER_DEBUG, "Expected a delim for attribute comparison, got: '{}'", delim_part.to_debug_string());
return ParseError::SyntaxError;
}
if (delim_part.token().delim() == '=') {
simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::ExactValueMatch;
} else {
if (!attribute_tokens.has_next_token()) {
dbgln_if(CSS_PARSER_DEBUG, "Attribute selector ended part way through a match type.");
return ParseError::SyntaxError;
}
auto const& delim_second_part = attribute_tokens.next_token();
if (!delim_second_part.is_delim('=')) {
dbgln_if(CSS_PARSER_DEBUG, "Expected a double delim for attribute comparison, got: '{}{}'", delim_part.to_debug_string(), delim_second_part.to_debug_string());
return ParseError::SyntaxError;
}
switch (delim_part.token().delim()) {
case '~':
simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::ContainsWord;
break;
case '*':
simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::ContainsString;
break;
case '|':
simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::StartsWithSegment;
break;
case '^':
simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::StartsWithString;
break;
case '$':
simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::EndsWithString;
break;
default:
attribute_tokens.reconsume_current_input_token();
}
}
attribute_tokens.skip_whitespace();
if (!attribute_tokens.has_next_token()) {
dbgln_if(CSS_PARSER_DEBUG, "Attribute selector ended without a value to match.");
return ParseError::SyntaxError;
}
auto const& value_part = attribute_tokens.next_token();
if (!value_part.is(Token::Type::Ident) && !value_part.is(Token::Type::String)) {
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;
}
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
if (attribute_tokens.has_next_token()) {
auto const& case_sensitivity_part = attribute_tokens.next_token();
if (case_sensitivity_part.is(Token::Type::Ident)) {
auto case_sensitivity = case_sensitivity_part.token().ident();
if (case_sensitivity.equals_ignoring_ascii_case("i"sv)) {
simple_selector.attribute().case_type = Selector::SimpleSelector::Attribute::CaseType::CaseInsensitiveMatch;
} else if (case_sensitivity.equals_ignoring_ascii_case("s"sv)) {
simple_selector.attribute().case_type = Selector::SimpleSelector::Attribute::CaseType::CaseSensitiveMatch;
} else {
dbgln_if(CSS_PARSER_DEBUG, "Expected a \"i\" or \"s\" attribute selector case sensitivity identifier, got: '{}'", case_sensitivity_part.to_debug_string());
return ParseError::SyntaxError;
}
} else {
dbgln_if(CSS_PARSER_DEBUG, "Expected an attribute selector case sensitivity identifier, got: '{}'", case_sensitivity_part.to_debug_string());
return ParseError::SyntaxError;
}
}
if (attribute_tokens.has_next_token()) {
dbgln_if(CSS_PARSER_DEBUG, "Was not expecting anything else inside attribute selector.");
return ParseError::SyntaxError;
}
return simple_selector;
}
Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_pseudo_simple_selector(TokenStream<ComponentValue>& tokens)
{
auto peek_token_ends_selector = [&]() -> bool {
auto const& value = tokens.peek_token();
return (value.is(Token::Type::EndOfFile) || value.is(Token::Type::Whitespace) || value.is(Token::Type::Comma));
};
if (peek_token_ends_selector())
return ParseError::SyntaxError;
bool is_pseudo = false;
if (tokens.peek_token().is(Token::Type::Colon)) {
is_pseudo = true;
tokens.next_token();
if (peek_token_ends_selector())
return ParseError::SyntaxError;
}
if (is_pseudo) {
auto const& name_token = tokens.next_token();
if (!name_token.is(Token::Type::Ident)) {
dbgln_if(CSS_PARSER_DEBUG, "Expected an ident for pseudo-element, got: '{}'", name_token.to_debug_string());
return ParseError::SyntaxError;
}
auto pseudo_name = name_token.token().ident();
auto pseudo_element = pseudo_element_from_string(pseudo_name);
// Note: We allow the "ignored" -webkit prefix here for -webkit-progress-bar/-webkit-progress-bar
if (!pseudo_element.has_value() && has_ignored_vendor_prefix(pseudo_name))
return ParseError::IncludesIgnoredVendorPrefix;
if (!pseudo_element.has_value()) {
dbgln_if(CSS_PARSER_DEBUG, "Unrecognized pseudo-element: '::{}'", pseudo_name);
return ParseError::SyntaxError;
}
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoElement,
.value = pseudo_element.value()
};
}
if (peek_token_ends_selector())
return ParseError::SyntaxError;
auto const& pseudo_class_token = tokens.next_token();
if (pseudo_class_token.is(Token::Type::Ident)) {
auto pseudo_name = pseudo_class_token.token().ident();
if (has_ignored_vendor_prefix(pseudo_name))
return ParseError::IncludesIgnoredVendorPrefix;
auto make_pseudo_class_selector = [](auto pseudo_class) {
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector { .type = pseudo_class }
};
};
if (auto pseudo_class = pseudo_class_from_string(pseudo_name); pseudo_class.has_value()) {
if (!pseudo_class_metadata(pseudo_class.value()).is_valid_as_identifier) {
dbgln_if(CSS_PARSER_DEBUG, "Pseudo-class ':{}' is only valid as a function", pseudo_name);
return ParseError::SyntaxError;
}
return make_pseudo_class_selector(pseudo_class.value());
}
// Single-colon syntax allowed for ::after, ::before, ::first-letter and ::first-line for compatibility.
// https://www.w3.org/TR/selectors/#pseudo-element-syntax
if (auto pseudo_element = pseudo_element_from_string(pseudo_name); pseudo_element.has_value()) {
switch (pseudo_element.value()) {
case Selector::PseudoElement::After:
case Selector::PseudoElement::Before:
case Selector::PseudoElement::FirstLetter:
case Selector::PseudoElement::FirstLine:
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoElement,
.value = pseudo_element.value()
};
default:
break;
}
}
dbgln_if(CSS_PARSER_DEBUG, "Unrecognized pseudo-class: ':{}'", pseudo_name);
return ParseError::SyntaxError;
}
if (pseudo_class_token.is_function()) {
auto parse_nth_child_selector = [this](auto pseudo_class, Vector<ComponentValue> const& function_values, bool allow_of = false) -> ParseErrorOr<Selector::SimpleSelector> {
auto tokens = TokenStream<ComponentValue>(function_values);
auto nth_child_pattern = parse_a_n_plus_b_pattern(tokens);
if (!nth_child_pattern.has_value()) {
dbgln_if(CSS_PARSER_DEBUG, "!!! Invalid An+B format for {}", pseudo_class_name(pseudo_class));
return ParseError::SyntaxError;
}
tokens.skip_whitespace();
if (!tokens.has_next_token()) {
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.nth_child_pattern = nth_child_pattern.release_value() }
};
}
if (!allow_of)
return ParseError::SyntaxError;
// Parse the `of <selector-list>` syntax
auto const& maybe_of = tokens.next_token();
if (!(maybe_of.is(Token::Type::Ident) && maybe_of.token().ident().equals_ignoring_ascii_case("of"sv)))
return ParseError::SyntaxError;
tokens.skip_whitespace();
auto selector_list = TRY(parse_a_selector_list(tokens, SelectorType::Standalone));
tokens.skip_whitespace();
if (tokens.has_next_token())
return ParseError::SyntaxError;
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.nth_child_pattern = nth_child_pattern.release_value(),
.argument_selector_list = move(selector_list) }
};
};
auto const& pseudo_function = pseudo_class_token.function();
auto maybe_pseudo_class = pseudo_class_from_string(pseudo_function.name());
if (!maybe_pseudo_class.has_value()) {
dbgln_if(CSS_PARSER_DEBUG, "Unrecognized pseudo-class function: ':{}'()", pseudo_function.name());
return ParseError::SyntaxError;
}
auto pseudo_class = maybe_pseudo_class.value();
auto metadata = pseudo_class_metadata(pseudo_class);
if (!metadata.is_valid_as_function) {
dbgln_if(CSS_PARSER_DEBUG, "Pseudo-class ':{}' is not valid as a function", pseudo_function.name());
return ParseError::SyntaxError;
}
if (pseudo_function.values().is_empty()) {
dbgln_if(CSS_PARSER_DEBUG, "Empty :{}() selector", pseudo_function.name());
return ParseError::SyntaxError;
}
switch (metadata.parameter_type) {
case PseudoClassMetadata::ParameterType::ANPlusB:
return parse_nth_child_selector(pseudo_class, pseudo_function.values(), false);
case PseudoClassMetadata::ParameterType::ANPlusBOf:
return parse_nth_child_selector(pseudo_class, pseudo_function.values(), true);
case PseudoClassMetadata::ParameterType::CompoundSelector: {
auto function_token_stream = TokenStream(pseudo_function.values());
auto compound_selector_or_error = parse_compound_selector(function_token_stream);
if (compound_selector_or_error.is_error() || !compound_selector_or_error.value().has_value()) {
dbgln_if(CSS_PARSER_DEBUG, "Failed to parse :{}() parameter as a compound selector", pseudo_function.name());
return ParseError::SyntaxError;
}
Vector compound_selectors { compound_selector_or_error.release_value().release_value() };
auto selector = Selector::create(move(compound_selectors));
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.argument_selector_list = { move(selector) } }
};
}
case PseudoClassMetadata::ParameterType::ForgivingSelectorList: {
auto function_token_stream = TokenStream(pseudo_function.values());
// NOTE: Because it's forgiving, even complete garbage will parse OK as an empty selector-list.
auto argument_selector_list = MUST(parse_a_selector_list(function_token_stream, SelectorType::Standalone, SelectorParsingMode::Forgiving));
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.argument_selector_list = move(argument_selector_list) }
};
}
case PseudoClassMetadata::ParameterType::Ident: {
auto function_token_stream = TokenStream(pseudo_function.values());
function_token_stream.skip_whitespace();
auto maybe_ident_token = function_token_stream.next_token();
function_token_stream.skip_whitespace();
if (!maybe_ident_token.is(Token::Type::Ident) || function_token_stream.has_next_token()) {
dbgln_if(CSS_PARSER_DEBUG, "Failed to parse :{}() parameter as an ident: not an ident", pseudo_function.name());
return ParseError::SyntaxError;
}
auto maybe_ident = value_id_from_string(maybe_ident_token.token().ident());
if (!maybe_ident.has_value()) {
dbgln_if(CSS_PARSER_DEBUG, "Failed to parse :{}() parameter as an ident: unrecognized ident", pseudo_function.name());
return ParseError::SyntaxError;
}
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.identifier = maybe_ident.value() }
};
}
case PseudoClassMetadata::ParameterType::LanguageRanges: {
Vector<FlyString> languages;
auto function_token_stream = TokenStream(pseudo_function.values());
auto language_token_lists = parse_a_comma_separated_list_of_component_values(function_token_stream);
for (auto language_token_list : language_token_lists) {
auto language_token_stream = TokenStream(language_token_list);
language_token_stream.skip_whitespace();
auto language_token = language_token_stream.next_token();
if (!(language_token.is(Token::Type::Ident) || language_token.is(Token::Type::String))) {
dbgln_if(CSS_PARSER_DEBUG, "Invalid language range in :{}() - not a string/ident", pseudo_function.name());
return ParseError::SyntaxError;
}
auto language_string = language_token.is(Token::Type::String) ? language_token.token().string() : language_token.token().ident();
languages.append(MUST(FlyString::from_utf8(language_string)));
language_token_stream.skip_whitespace();
if (language_token_stream.has_next_token()) {
dbgln_if(CSS_PARSER_DEBUG, "Invalid language range in :{}() - trailing tokens", pseudo_function.name());
return ParseError::SyntaxError;
}
}
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.languages = move(languages) }
};
}
case PseudoClassMetadata::ParameterType::SelectorList: {
auto function_token_stream = TokenStream(pseudo_function.values());
auto not_selector = TRY(parse_a_selector_list(function_token_stream, SelectorType::Standalone));
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::PseudoClass,
.value = Selector::SimpleSelector::PseudoClassSelector {
.type = pseudo_class,
.argument_selector_list = move(not_selector) }
};
}
case PseudoClassMetadata::ParameterType::None:
// `None` means this is not a function-type pseudo-class, so this state should be impossible.
VERIFY_NOT_REACHED();
}
}
dbgln_if(CSS_PARSER_DEBUG, "Unexpected Block in pseudo-class name, expected a function or identifier. '{}'", pseudo_class_token.to_debug_string());
return ParseError::SyntaxError;
}
Parser::ParseErrorOr<Optional<Selector::SimpleSelector>> Parser::parse_simple_selector(TokenStream<ComponentValue>& tokens)
{
auto peek_token_ends_selector = [&]() -> bool {
auto const& value = tokens.peek_token();
return (value.is(Token::Type::EndOfFile) || value.is(Token::Type::Whitespace) || value.is(Token::Type::Comma));
};
if (peek_token_ends_selector())
return Optional<Selector::SimpleSelector> {};
// Handle universal and tag-name types together, since both can be namespaced
if (auto qualified_name = parse_selector_qualified_name(tokens, AllowWildcardName::Yes); qualified_name.has_value()) {
if (qualified_name->name.name == "*"sv) {
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::Universal,
.value = qualified_name.release_value(),
};
}
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::TagName,
.value = qualified_name.release_value(),
};
}
auto const& first_value = tokens.next_token();
if (first_value.is(Token::Type::Delim)) {
u32 delim = first_value.token().delim();
switch (delim) {
case '*':
// Handled already
VERIFY_NOT_REACHED();
case '.': {
if (peek_token_ends_selector())
return ParseError::SyntaxError;
auto const& class_name_value = tokens.next_token();
if (!class_name_value.is(Token::Type::Ident)) {
dbgln_if(CSS_PARSER_DEBUG, "Expected an ident after '.', got: {}", class_name_value.to_debug_string());
return ParseError::SyntaxError;
}
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::Class,
.value = Selector::SimpleSelector::Name { FlyString::from_utf8(class_name_value.token().ident()).release_value_but_fixme_should_propagate_errors() }
};
}
case '>':
case '+':
case '~':
case '|':
// Whitespace is not required between the compound-selector and a combinator.
// So, if we see a combinator, return that this compound-selector is done, instead of a syntax error.
tokens.reconsume_current_input_token();
return Optional<Selector::SimpleSelector> {};
default:
dbgln_if(CSS_PARSER_DEBUG, "!!! Invalid simple selector!");
return ParseError::SyntaxError;
}
}
if (first_value.is(Token::Type::Hash)) {
if (first_value.token().hash_type() != Token::HashType::Id) {
dbgln_if(CSS_PARSER_DEBUG, "Selector contains hash token that is not an id: {}", first_value.to_debug_string());
return ParseError::SyntaxError;
}
return Selector::SimpleSelector {
.type = Selector::SimpleSelector::Type::Id,
.value = Selector::SimpleSelector::Name { FlyString::from_utf8(first_value.token().hash_value()).release_value_but_fixme_should_propagate_errors() }
};
}
if (first_value.is_block() && first_value.block().is_square())
return TRY(parse_attribute_simple_selector(first_value));
if (first_value.is(Token::Type::Colon))
return TRY(parse_pseudo_simple_selector(tokens));
dbgln_if(CSS_PARSER_DEBUG, "!!! Invalid simple selector!");
return ParseError::SyntaxError;
}
Optional<Selector::SimpleSelector::ANPlusBPattern> Parser::parse_a_n_plus_b_pattern(TokenStream<ComponentValue>& values)
{
auto transaction = values.begin_transaction();
auto syntax_error = [&]() -> Optional<Selector::SimpleSelector::ANPlusBPattern> {
if constexpr (CSS_PARSER_DEBUG) {
dbgln_if(CSS_PARSER_DEBUG, "Invalid An+B value:");
values.dump_all_tokens();
}
return {};
};
auto is_n = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Ident) && value.token().ident().equals_ignoring_ascii_case("n"sv);
};
auto is_ndash = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Ident) && value.token().ident().equals_ignoring_ascii_case("n-"sv);
};
auto is_dashn = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Ident) && value.token().ident().equals_ignoring_ascii_case("-n"sv);
};
auto is_dashndash = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Ident) && value.token().ident().equals_ignoring_ascii_case("-n-"sv);
};
auto is_sign = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Delim) && (value.token().delim() == '+' || value.token().delim() == '-');
};
auto is_n_dimension = [](ComponentValue const& value) -> bool {
if (!value.is(Token::Type::Dimension))
return false;
if (!value.token().number().is_integer())
return false;
if (!value.token().dimension_unit().equals_ignoring_ascii_case("n"sv))
return false;
return true;
};
auto is_ndash_dimension = [](ComponentValue const& value) -> bool {
if (!value.is(Token::Type::Dimension))
return false;
if (!value.token().number().is_integer())
return false;
if (!value.token().dimension_unit().equals_ignoring_ascii_case("n-"sv))
return false;
return true;
};
auto is_ndashdigit_dimension = [](ComponentValue const& value) -> bool {
if (!value.is(Token::Type::Dimension))
return false;
if (!value.token().number().is_integer())
return false;
auto dimension_unit = value.token().dimension_unit();
if (!dimension_unit.starts_with("n-"sv, CaseSensitivity::CaseInsensitive))
return false;
for (size_t i = 2; i < dimension_unit.length(); ++i) {
if (!is_ascii_digit(dimension_unit[i]))
return false;
}
return true;
};
auto is_ndashdigit_ident = [](ComponentValue const& value) -> bool {
if (!value.is(Token::Type::Ident))
return false;
auto ident = value.token().ident();
if (!ident.starts_with("n-"sv, CaseSensitivity::CaseInsensitive))
return false;
for (size_t i = 2; i < ident.length(); ++i) {
if (!is_ascii_digit(ident[i]))
return false;
}
return true;
};
auto is_dashndashdigit_ident = [](ComponentValue const& value) -> bool {
if (!value.is(Token::Type::Ident))
return false;
auto ident = value.token().ident();
if (!ident.starts_with("-n-"sv, CaseSensitivity::CaseInsensitive))
return false;
if (ident.length() == 3)
return false;
for (size_t i = 3; i < ident.length(); ++i) {
if (!is_ascii_digit(ident[i]))
return false;
}
return true;
};
auto is_integer = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Number) && value.token().number().is_integer();
};
auto is_signed_integer = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Number) && value.token().number().is_integer_with_explicit_sign();
};
auto is_signless_integer = [](ComponentValue const& value) -> bool {
return value.is(Token::Type::Number) && !value.token().number().is_integer_with_explicit_sign();
};
// https://www.w3.org/TR/css-syntax-3/#the-anb-type
// Unfortunately these can't be in the same order as in the spec.
values.skip_whitespace();
auto const& first_value = values.next_token();
// odd | even
if (first_value.is(Token::Type::Ident)) {
auto ident = first_value.token().ident();
if (ident.equals_ignoring_ascii_case("odd"sv)) {
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 2, 1 };
}
if (ident.equals_ignoring_ascii_case("even"sv)) {
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 2, 0 };
}
}
// <integer>
if (is_integer(first_value)) {
int b = first_value.token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 0, b };
}
// <n-dimension>
// <n-dimension> <signed-integer>
// <n-dimension> ['+' | '-'] <signless-integer>
if (is_n_dimension(first_value)) {
int a = first_value.token().dimension_value_int();
values.skip_whitespace();
// <n-dimension> <signed-integer>
if (is_signed_integer(values.peek_token())) {
int b = values.next_token().token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { a, b };
}
// <n-dimension> ['+' | '-'] <signless-integer>
{
auto child_transaction = transaction.create_child();
auto const& second_value = values.next_token();
values.skip_whitespace();
auto const& third_value = values.next_token();
if (is_sign(second_value) && is_signless_integer(third_value)) {
int b = third_value.token().to_integer() * (second_value.is_delim('+') ? 1 : -1);
child_transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { a, b };
}
}
// <n-dimension>
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { a, 0 };
}
// <ndash-dimension> <signless-integer>
if (is_ndash_dimension(first_value)) {
values.skip_whitespace();
auto const& second_value = values.next_token();
if (is_signless_integer(second_value)) {
int a = first_value.token().dimension_value_int();
int b = -second_value.token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { a, b };
}
return syntax_error();
}
// <ndashdigit-dimension>
if (is_ndashdigit_dimension(first_value)) {
auto const& dimension = first_value.token();
int a = dimension.dimension_value_int();
auto maybe_b = dimension.dimension_unit().substring_view(1).to_int();
if (maybe_b.has_value()) {
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { a, maybe_b.value() };
}
return syntax_error();
}
// <dashndashdigit-ident>
if (is_dashndashdigit_ident(first_value)) {
auto maybe_b = first_value.token().ident().substring_view(2).to_int();
if (maybe_b.has_value()) {
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { -1, maybe_b.value() };
}
return syntax_error();
}
// -n
// -n <signed-integer>
// -n ['+' | '-'] <signless-integer>
if (is_dashn(first_value)) {
values.skip_whitespace();
// -n <signed-integer>
if (is_signed_integer(values.peek_token())) {
int b = values.next_token().token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { -1, b };
}
// -n ['+' | '-'] <signless-integer>
{
auto child_transaction = transaction.create_child();
auto const& second_value = values.next_token();
values.skip_whitespace();
auto const& third_value = values.next_token();
if (is_sign(second_value) && is_signless_integer(third_value)) {
int b = third_value.token().to_integer() * (second_value.is_delim('+') ? 1 : -1);
child_transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { -1, b };
}
}
// -n
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { -1, 0 };
}
// -n- <signless-integer>
if (is_dashndash(first_value)) {
values.skip_whitespace();
auto const& second_value = values.next_token();
if (is_signless_integer(second_value)) {
int b = -second_value.token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { -1, b };
}
return syntax_error();
}
// All that's left now are these:
// '+'?† n
// '+'?† n <signed-integer>
// '+'?† n ['+' | '-'] <signless-integer>
// '+'?† n- <signless-integer>
// '+'?† <ndashdigit-ident>
// In all of these cases, the + is optional, and has no effect.
// So, we just skip the +, and carry on.
if (!first_value.is_delim('+')) {
values.reconsume_current_input_token();
// We do *not* skip whitespace here.
}
auto const& first_after_plus = values.next_token();
// '+'?† n
// '+'?† n <signed-integer>
// '+'?† n ['+' | '-'] <signless-integer>
if (is_n(first_after_plus)) {
values.skip_whitespace();
// '+'?† n <signed-integer>
if (is_signed_integer(values.peek_token())) {
int b = values.next_token().token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 1, b };
}
// '+'?† n ['+' | '-'] <signless-integer>
{
auto child_transaction = transaction.create_child();
auto const& second_value = values.next_token();
values.skip_whitespace();
auto const& third_value = values.next_token();
if (is_sign(second_value) && is_signless_integer(third_value)) {
int b = third_value.token().to_integer() * (second_value.is_delim('+') ? 1 : -1);
child_transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 1, b };
}
}
// '+'?† n
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 1, 0 };
}
// '+'?† n- <signless-integer>
if (is_ndash(first_after_plus)) {
values.skip_whitespace();
auto const& second_value = values.next_token();
if (is_signless_integer(second_value)) {
int b = -second_value.token().to_integer();
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 1, b };
}
return syntax_error();
}
// '+'?† <ndashdigit-ident>
if (is_ndashdigit_ident(first_after_plus)) {
auto maybe_b = first_after_plus.token().ident().substring_view(1).to_int();
if (maybe_b.has_value()) {
transaction.commit();
return Selector::SimpleSelector::ANPlusBPattern { 1, maybe_b.value() };
}
return syntax_error();
}
return syntax_error();
}
}
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