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ladybird/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
Sam Atkins ffc81cbfad LibWeb: Use Selectors instead of a String for :not() selectors 
Rather than parsing the selector every time we want to check it, we
now parse it once at the beginning.

A bonus effect of this is that we now support a selector list in
:not(), instead of just a single selector, though only when using
the new parser.
2021-07-14 13:31:00 +02:00

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020-2021, the SerenityOS developers.
* Copyright (c) 2021, Sam Atkins <atkinssj@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/NonnullRefPtrVector.h>
#include <AK/SourceLocation.h>
#include <LibWeb/CSS/CSSStyleDeclaration.h>
#include <LibWeb/CSS/CSSStyleRule.h>
#include <LibWeb/CSS/CSSStyleSheet.h>
#include <LibWeb/CSS/Parser/DeclarationOrAtRule.h>
#include <LibWeb/CSS/Parser/Parser.h>
#include <LibWeb/CSS/Parser/StyleBlockRule.h>
#include <LibWeb/CSS/Parser/StyleComponentValueRule.h>
#include <LibWeb/CSS/Parser/StyleFunctionRule.h>
#include <LibWeb/CSS/Parser/StyleRule.h>
#include <LibWeb/CSS/Selector.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/Dump.h>
#define CSS_PARSER_TRACE 1
static void log_parse_error(const SourceLocation& location = SourceLocation::current())
{
dbgln_if(CSS_PARSER_TRACE, "Parse error (CSS) {}", location);
}
namespace Web::CSS {
ParsingContext::ParsingContext()
{
}
ParsingContext::ParsingContext(DOM::Document const& document)
: m_document(&document)
{
}
ParsingContext::ParsingContext(DOM::ParentNode const& parent_node)
: m_document(&parent_node.document())
{
}
bool ParsingContext::in_quirks_mode() const
{
return m_document ? m_document->in_quirks_mode() : false;
}
URL ParsingContext::complete_url(String const& addr) const
{
return m_document ? m_document->url().complete_url(addr) : URL::create_with_url_or_path(addr);
}
template<typename T>
TokenStream<T>::TokenStream(Vector<T> const& tokens)
: m_tokens(tokens)
, m_eof(make_eof())
{
}
template<typename T>
TokenStream<T>::~TokenStream()
{
}
template<typename T>
bool TokenStream<T>::has_next_token()
{
return (size_t)(m_iterator_offset + 1) < m_tokens.size();
}
template<typename T>
T const& TokenStream<T>::peek_token()
{
if (!has_next_token())
return m_eof;
return m_tokens.at(m_iterator_offset + 1);
}
template<typename T>
T const& TokenStream<T>::next_token()
{
if (!has_next_token())
return m_eof;
++m_iterator_offset;
return m_tokens.at(m_iterator_offset);
}
template<typename T>
T const& TokenStream<T>::current_token()
{
if ((size_t)m_iterator_offset >= m_tokens.size())
return m_eof;
return m_tokens.at(m_iterator_offset);
}
template<typename T>
void TokenStream<T>::reconsume_current_input_token()
{
VERIFY(m_iterator_offset >= 0);
--m_iterator_offset;
}
template<typename T>
void TokenStream<T>::skip_whitespace()
{
while (peek_token().is(Token::Type::Whitespace))
next_token();
}
template<>
Token TokenStream<Token>::make_eof()
{
return Tokenizer::create_eof_token();
}
template<>
StyleComponentValueRule TokenStream<StyleComponentValueRule>::make_eof()
{
return StyleComponentValueRule(Tokenizer::create_eof_token());
}
template<typename T>
void TokenStream<T>::dump_all_tokens()
{
dbgln("Dumping all tokens:");
for (auto& token : m_tokens)
dbgln("{}", token.to_debug_string());
}
Parser::Parser(ParsingContext const& context, StringView const& input, String const& encoding)
: m_context(context)
, m_tokenizer(input, encoding)
, m_tokens(m_tokenizer.parse())
, m_token_stream(TokenStream(m_tokens))
{
}
Parser::~Parser()
{
}
NonnullRefPtr<CSSStyleSheet> Parser::parse_as_stylesheet()
{
return parse_as_stylesheet(m_token_stream);
}
template<typename T>
NonnullRefPtr<CSSStyleSheet> Parser::parse_as_stylesheet(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_stylesheet");
auto parser_rules = consume_a_list_of_rules(tokens, true);
NonnullRefPtrVector<CSSRule> rules;
for (auto& raw_rule : parser_rules) {
auto rule = convert_to_rule(raw_rule);
if (rule)
rules.append(*rule);
}
auto stylesheet = CSSStyleSheet::create(rules);
dump_sheet(stylesheet);
return stylesheet;
}
NonnullRefPtrVector<Selector> Parser::parse_a_selector()
{
return parse_a_selector(m_token_stream);
}
template<typename T>
NonnullRefPtrVector<Selector> Parser::parse_a_selector(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_a_selector");
auto comma_separated_lists = parse_as_comma_separated_list_of_component_values(tokens);
NonnullRefPtrVector<Selector> selectors;
for (auto& selector_parts : comma_separated_lists) {
auto stream = TokenStream(selector_parts);
auto selector = parse_single_selector(stream);
if (selector)
selectors.append(selector.release_nonnull());
}
return selectors;
}
NonnullRefPtrVector<Selector> Parser::parse_a_relative_selector()
{
return parse_a_relative_selector(m_token_stream);
}
template<typename T>
NonnullRefPtrVector<Selector> Parser::parse_a_relative_selector(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_a_relative_selector");
auto comma_separated_lists = parse_as_comma_separated_list_of_component_values(tokens);
NonnullRefPtrVector<Selector> selectors;
for (auto& selector_parts : comma_separated_lists) {
auto stream = TokenStream(selector_parts);
auto selector = parse_single_selector(stream, true);
if (selector)
selectors.append(selector.release_nonnull());
}
return selectors;
}
template<typename T>
RefPtr<Selector> Parser::parse_single_selector(TokenStream<T>& tokens, bool is_relative)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_single_selector");
// FIXME: Bring this all in line with the spec. https://www.w3.org/TR/selectors-4/
Vector<Selector::ComplexSelector> selectors;
auto check_for_eof_or_whitespace = [&](T& current_value) -> bool {
if (current_value.is(Token::Type::EndOfFile))
return true;
if (current_value.is(Token::Type::Whitespace)) {
tokens.reconsume_current_input_token();
return true;
}
return false;
};
auto parse_simple_selector = [&]() -> Optional<Selector::SimpleSelector> {
auto current_value = tokens.next_token();
if (check_for_eof_or_whitespace(current_value))
return {};
Selector::SimpleSelector simple_selector;
// FIXME: Handle namespace prefixes.
if (current_value.is(Token::Type::Delim) && ((Token)current_value).delim() == "*") {
simple_selector.type = Selector::SimpleSelector::Type::Universal;
} else if (current_value.is(Token::Type::Hash)) {
if (((Token)current_value).m_hash_type != Token::HashType::Id) {
dbgln("Selector contains hash token that is not an id: {}", current_value.to_debug_string());
return {};
}
simple_selector.type = Selector::SimpleSelector::Type::Id;
simple_selector.value = ((Token)current_value).m_value.to_string();
} else if (current_value.is(Token::Type::Delim) && ((Token)current_value).delim() == ".") {
current_value = tokens.next_token();
if (check_for_eof_or_whitespace(current_value))
return {};
if (!current_value.is(Token::Type::Ident)) {
dbgln("Expected an ident after '.', got: {}", current_value.to_debug_string());
return {};
}
simple_selector.type = Selector::SimpleSelector::Type::Class;
simple_selector.value = current_value.token().ident().to_lowercase_string();
} else if (current_value.is(Token::Type::Ident)) {
simple_selector.type = Selector::SimpleSelector::Type::TagName;
simple_selector.value = current_value.token().ident().to_lowercase_string();
} else if (current_value.is_block() && current_value.block().is_square()) {
simple_selector.type = Selector::SimpleSelector::Type::Attribute;
auto& attribute = simple_selector.attribute;
Vector<StyleComponentValueRule> const& attribute_parts = current_value.block().values();
if (attribute_parts.is_empty()) {
dbgln("CSS attribute selector is empty!");
return {};
}
// FIXME: Handle namespace prefix for attribute name.
auto& attribute_part = attribute_parts.first();
if (!attribute_part.is(Token::Type::Ident)) {
dbgln("Expected ident for attribute name, got: '{}'", attribute_part.to_debug_string());
return {};
}
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::HasAttribute;
attribute.name = attribute_part.token().ident();
if (attribute_parts.size() == 1)
return simple_selector;
size_t attribute_index = 1;
auto& delim_part = attribute_parts.at(attribute_index);
if (!delim_part.is(Token::Type::Delim)) {
dbgln("Expected a delim for attribute comparison, got: '{}'", delim_part.to_debug_string());
return {};
}
if (delim_part.token().delim() == "=") {
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::ExactValueMatch;
attribute_index++;
} else {
attribute_index++;
if (attribute_index >= attribute_parts.size()) {
dbgln("Attribute selector ended part way through a match type.");
return {};
}
auto& delim_second_part = attribute_parts.at(attribute_index);
if (!(delim_second_part.is(Token::Type::Delim) && delim_second_part.token().delim() == "=")) {
dbgln("Expected a double delim for attribute comparison, got: '{}{}'", delim_part.to_debug_string(), delim_second_part.to_debug_string());
return {};
}
if (delim_part.token().delim() == "~") {
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::ContainsWord;
attribute_index++;
} else if (delim_part.token().delim() == "*") {
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::ContainsString;
attribute_index++;
} else if (delim_part.token().delim() == "|") {
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::StartsWithSegment;
attribute_index++;
} else if (delim_part.token().delim() == "^") {
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::StartsWithString;
attribute_index++;
} else if (delim_part.token().delim() == "$") {
attribute.match_type = Selector::SimpleSelector::Attribute::MatchType::EndsWithString;
attribute_index++;
}
}
if (attribute_index >= attribute_parts.size()) {
dbgln("Attribute selector ended without a value to match.");
return {};
}
auto& value_part = attribute_parts.at(attribute_index);
if (!value_part.is(Token::Type::Ident) && !value_part.is(Token::Type::String)) {
dbgln("Expected a string or ident for the value to match attribute against, got: '{}'", value_part.to_debug_string());
return {};
}
attribute.value = value_part.token().is(Token::Type::Ident) ? value_part.token().ident() : value_part.token().string();
// FIXME: Handle case-sensitivity suffixes. https://www.w3.org/TR/selectors-4/#attribute-case
} else if (current_value.is(Token::Type::Colon)) {
bool is_pseudo = false;
current_value = tokens.next_token();
if (check_for_eof_or_whitespace(current_value))
return {};
if (current_value.is(Token::Type::Colon)) {
is_pseudo = true;
current_value = tokens.next_token();
if (check_for_eof_or_whitespace(current_value))
return {};
}
if (is_pseudo) {
auto pseudo_name = ((Token)current_value).ident();
simple_selector.type = Selector::SimpleSelector::Type::PseudoElement;
if (pseudo_name.equals_ignoring_case("before")) {
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::Before;
} else if (pseudo_name.equals_ignoring_case("after")) {
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::After;
} else if (pseudo_name.equals_ignoring_case("first-line")) {
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::FirstLine;
} else if (pseudo_name.equals_ignoring_case("first-letter")) {
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::FirstLetter;
} else {
return {};
}
return simple_selector;
}
auto& pseudo_class = simple_selector.pseudo_class;
current_value = tokens.next_token();
if (check_for_eof_or_whitespace(current_value))
return {};
simple_selector.type = Selector::SimpleSelector::Type::PseudoClass;
if (current_value.is(Token::Type::Ident)) {
auto pseudo_name = ((Token)current_value).ident();
if (pseudo_name.equals_ignoring_case("link")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Link;
} else if (pseudo_name.equals_ignoring_case("visited")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Visited;
} else if (pseudo_name.equals_ignoring_case("active")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Active;
} else if (pseudo_name.equals_ignoring_case("hover")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Hover;
} else if (pseudo_name.equals_ignoring_case("focus")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Focus;
} else if (pseudo_name.equals_ignoring_case("first-child")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::FirstChild;
} else if (pseudo_name.equals_ignoring_case("last-child")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::LastChild;
} else if (pseudo_name.equals_ignoring_case("only-child")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::OnlyChild;
} else if (pseudo_name.equals_ignoring_case("empty")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Empty;
} else if (pseudo_name.equals_ignoring_case("root")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Root;
} else if (pseudo_name.equals_ignoring_case("first-of-type")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::FirstOfType;
} else if (pseudo_name.equals_ignoring_case("last-of-type")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::LastOfType;
} else if (pseudo_name.equals_ignoring_case("before")) {
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::Before;
} else if (pseudo_name.equals_ignoring_case("after")) {
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::After;
} else if (pseudo_name.equals_ignoring_case("disabled")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Disabled;
} else if (pseudo_name.equals_ignoring_case("enabled")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Enabled;
} else if (pseudo_name.equals_ignoring_case("checked")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Checked;
} else if (pseudo_name.equals_ignoring_case("before")) {
// Single-colon syntax allowed for compatibility. https://www.w3.org/TR/selectors/#pseudo-element-syntax
simple_selector.type = Selector::SimpleSelector::Type::PseudoElement;
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::Before;
} else if (pseudo_name.equals_ignoring_case("after")) {
// See :before
simple_selector.type = Selector::SimpleSelector::Type::PseudoElement;
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::After;
} else if (pseudo_name.equals_ignoring_case("first-line")) {
// See :before
simple_selector.type = Selector::SimpleSelector::Type::PseudoElement;
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::FirstLine;
} else if (pseudo_name.equals_ignoring_case("first-letter")) {
// See :before
simple_selector.type = Selector::SimpleSelector::Type::PseudoElement;
simple_selector.pseudo_element = Selector::SimpleSelector::PseudoElement::FirstLetter;
} else {
dbgln("Unknown pseudo class: '{}'", pseudo_name);
return simple_selector;
}
} else if (current_value.is(Token::Type::Function)) {
auto& pseudo_function = current_value.function();
if (pseudo_function.name().equals_ignoring_case("nth-child")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::NthChild;
auto function_values = TokenStream<StyleComponentValueRule>(pseudo_function.values());
auto nth_child_pattern = parse_nth_child_pattern(function_values);
if (nth_child_pattern.has_value()) {
pseudo_class.nth_child_pattern = nth_child_pattern.value();
} else {
dbgln("Invalid nth-child format");
return {};
}
} else if (pseudo_function.name().equals_ignoring_case("nth-last-child")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::NthLastChild;
auto function_values = TokenStream<StyleComponentValueRule>(pseudo_function.values());
auto nth_child_pattern = parse_nth_child_pattern(function_values);
if (nth_child_pattern.has_value()) {
pseudo_class.nth_child_pattern = nth_child_pattern.value();
} else {
dbgln("Invalid nth-child format");
return {};
}
} else if (pseudo_function.name().equals_ignoring_case("not")) {
pseudo_class.type = Selector::SimpleSelector::PseudoClass::Type::Not;
auto function_token_stream = TokenStream(pseudo_function.values());
pseudo_class.not_selector = parse_a_selector(function_token_stream);
} else {
dbgln("Unknown pseudo class: '{}'()", pseudo_function.name());
return {};
}
} else {
dbgln("Unexpected Block in pseudo-class name, expected a function or identifier. '{}'", current_value.to_debug_string());
return {};
}
} else {
dbgln("Invalid simple selector!");
return {};
}
return simple_selector;
};
auto parse_complex_selector = [&]() -> Optional<Selector::ComplexSelector> {
auto relation = Selector::ComplexSelector::Relation::Descendant;
tokens.skip_whitespace();
auto current_value = tokens.peek_token();
if (current_value.is(Token::Type::Delim)) {
auto delim = ((Token)current_value).delim();
if (delim == ">") {
relation = Selector::ComplexSelector::Relation::ImmediateChild;
tokens.next_token();
} else if (delim == "+") {
relation = Selector::ComplexSelector::Relation::AdjacentSibling;
tokens.next_token();
} else if (delim == "~") {
relation = Selector::ComplexSelector::Relation::GeneralSibling;
tokens.next_token();
} else if (delim == "|") {
tokens.next_token();
auto next = tokens.peek_token();
if (next.is(Token::Type::EndOfFile))
return {};
if (next.is(Token::Type::Delim) && next.token().delim() == "|") {
relation = Selector::ComplexSelector::Relation::Column;
tokens.next_token();
}
}
}
tokens.skip_whitespace();
Vector<Selector::SimpleSelector> simple_selectors;
for (;;) {
auto current_value = tokens.peek_token();
if (current_value.is(Token::Type::EndOfFile) || current_value.is(Token::Type::Whitespace))
break;
auto component = parse_simple_selector();
if (!component.has_value())
break;
simple_selectors.append(component.value());
}
if (simple_selectors.is_empty())
return {};
return Selector::ComplexSelector { relation, move(simple_selectors) };
};
for (;;) {
auto current_value = tokens.peek_token();
if (current_value.is(Token::Type::EndOfFile))
break;
auto complex = parse_complex_selector();
if (complex.has_value())
selectors.append(complex.value());
}
if (selectors.is_empty())
return {};
if (!is_relative)
selectors.first().relation = Selector::ComplexSelector::Relation::None;
return Selector::create(move(selectors));
}
NonnullRefPtrVector<StyleRule> Parser::consume_a_list_of_rules(bool top_level)
{
return consume_a_list_of_rules(m_token_stream, top_level);
}
template<typename T>
NonnullRefPtrVector<StyleRule> Parser::consume_a_list_of_rules(TokenStream<T>& tokens, bool top_level)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_list_of_rules");
NonnullRefPtrVector<StyleRule> rules;
for (;;) {
auto token = tokens.next_token();
if (token.is(Token::Type::Whitespace)) {
continue;
}
if (token.is(Token::Type::EndOfFile)) {
break;
}
if (token.is(Token::Type::CDO) || token.is(Token::Type::CDC)) {
if (top_level) {
continue;
}
tokens.reconsume_current_input_token();
auto maybe_qualified = consume_a_qualified_rule(tokens);
if (maybe_qualified) {
rules.append(maybe_qualified.release_nonnull());
}
continue;
}
if (token.is(Token::Type::AtKeyword)) {
tokens.reconsume_current_input_token();
rules.append(consume_an_at_rule(tokens));
continue;
}
tokens.reconsume_current_input_token();
auto maybe_qualified = consume_a_qualified_rule(tokens);
if (maybe_qualified) {
rules.append(maybe_qualified.release_nonnull());
}
}
return rules;
}
NonnullRefPtr<StyleRule> Parser::consume_an_at_rule()
{
return consume_an_at_rule(m_token_stream);
}
template<typename T>
NonnullRefPtr<StyleRule> Parser::consume_an_at_rule(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_an_at_rule");
auto name_ident = tokens.next_token();
VERIFY(name_ident.is(Token::Type::Ident));
NonnullRefPtr<StyleRule> rule = create<StyleRule>(StyleRule::Type::At);
rule->m_name = ((Token)name_ident).ident();
for (;;) {
auto token = tokens.next_token();
if (token.is(Token::Type::Semicolon)) {
return rule;
}
if (token.is(Token::Type::EndOfFile)) {
log_parse_error();
return rule;
}
if (token.is(Token::Type::OpenCurly)) {
rule->m_block = consume_a_simple_block(tokens);
return rule;
}
// how is "simple block with an associated token of <{-token>" a valid token?
tokens.reconsume_current_input_token();
auto value = consume_a_component_value(tokens);
rule->m_prelude.append(value);
}
}
RefPtr<StyleRule> Parser::consume_a_qualified_rule()
{
return consume_a_qualified_rule(m_token_stream);
}
template<typename T>
RefPtr<StyleRule> Parser::consume_a_qualified_rule(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_qualified_rule");
NonnullRefPtr<StyleRule> rule = create<StyleRule>(StyleRule::Type::Qualified);
for (;;) {
auto token = tokens.next_token();
if (token.is(Token::Type::EndOfFile)) {
log_parse_error();
return {};
}
if (token.is(Token::Type::OpenCurly)) {
rule->m_block = consume_a_simple_block(tokens);
return rule;
}
// how is "simple block with an associated token of <{-token>" a valid token?
tokens.reconsume_current_input_token();
auto value = consume_a_component_value(tokens);
rule->m_prelude.append(value);
}
return rule;
}
template<>
StyleComponentValueRule Parser::consume_a_component_value(TokenStream<StyleComponentValueRule>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_component_value - shortcut: '{}'", tokens.peek_token().to_debug_string());
return tokens.next_token();
}
template<typename T>
StyleComponentValueRule Parser::consume_a_component_value(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_component_value");
auto token = tokens.next_token();
if (token.is(Token::Type::OpenCurly) || token.is(Token::Type::OpenSquare) || token.is(Token::Type::OpenParen))
return StyleComponentValueRule(consume_a_simple_block(tokens));
if (token.is(Token::Type::Function))
return StyleComponentValueRule(consume_a_function(tokens));
return StyleComponentValueRule(token);
}
StyleComponentValueRule Parser::consume_a_component_value()
{
return consume_a_component_value(m_token_stream);
}
NonnullRefPtr<StyleBlockRule> Parser::consume_a_simple_block()
{
return consume_a_simple_block(m_token_stream);
}
template<typename T>
NonnullRefPtr<StyleBlockRule> Parser::consume_a_simple_block(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_simple_block");
auto ending_token = ((Token)tokens.current_token()).mirror_variant();
NonnullRefPtr<StyleBlockRule> block = create<StyleBlockRule>();
block->m_token = tokens.current_token();
for (;;) {
auto token = tokens.next_token();
if (token.is(ending_token)) {
return block;
}
if (token.is(Token::Type::EndOfFile)) {
log_parse_error();
return block;
}
tokens.reconsume_current_input_token();
auto value = consume_a_component_value(tokens);
block->m_values.append(value);
}
}
NonnullRefPtr<StyleFunctionRule> Parser::consume_a_function()
{
return consume_a_function(m_token_stream);
}
template<typename T>
NonnullRefPtr<StyleFunctionRule> Parser::consume_a_function(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_function");
auto name_ident = tokens.current_token();
VERIFY(name_ident.is(Token::Type::Function));
NonnullRefPtr<StyleFunctionRule> function = create<StyleFunctionRule>(((Token)name_ident).m_value.to_string());
for (;;) {
auto token = tokens.next_token();
if (token.is(Token::Type::CloseParen)) {
return function;
}
if (token.is(Token::Type::EndOfFile)) {
log_parse_error();
return function;
}
tokens.reconsume_current_input_token();
auto value = consume_a_component_value(tokens);
function->m_values.append(value);
}
return function;
}
Optional<StyleDeclarationRule> Parser::consume_a_declaration()
{
return consume_a_declaration(m_token_stream);
}
template<typename T>
Optional<StyleDeclarationRule> Parser::consume_a_declaration(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_declaration");
auto token = tokens.next_token();
StyleDeclarationRule declaration;
VERIFY(token.is(Token::Type::Ident));
declaration.m_name = ((Token)token).ident();
tokens.skip_whitespace();
auto colon = tokens.next_token();
if (!colon.is(Token::Type::Colon)) {
log_parse_error();
return {};
}
tokens.skip_whitespace();
for (;;) {
if (tokens.peek_token().is(Token::Type::EndOfFile)) {
break;
}
declaration.m_values.append(consume_a_component_value(tokens));
}
if (declaration.m_values.size() >= 2) {
auto second_last = declaration.m_values.at(declaration.m_values.size() - 2);
auto last = declaration.m_values.at(declaration.m_values.size() - 1);
if (second_last.m_type == StyleComponentValueRule::ComponentType::Token && last.m_type == StyleComponentValueRule::ComponentType::Token) {
auto last_token = last.m_token;
auto second_last_token = second_last.m_token;
if (second_last_token.is(Token::Type::Delim) && second_last_token.m_value.to_string().equals_ignoring_case("!")) {
if (last_token.is(Token::Type::Ident) && last_token.m_value.to_string().equals_ignoring_case("important")) {
declaration.m_values.remove(declaration.m_values.size() - 2);
declaration.m_values.remove(declaration.m_values.size() - 1);
declaration.m_important = true;
}
}
}
}
while (!declaration.m_values.is_empty()) {
auto maybe_whitespace = declaration.m_values.last();
if (!(maybe_whitespace.is(Token::Type::Whitespace))) {
break;
}
declaration.m_values.take_last();
}
return declaration;
}
Vector<DeclarationOrAtRule> Parser::consume_a_list_of_declarations()
{
return consume_a_list_of_declarations(m_token_stream);
}
template<typename T>
Vector<DeclarationOrAtRule> Parser::consume_a_list_of_declarations(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::consume_a_list_of_declarations");
Vector<DeclarationOrAtRule> list;
for (;;) {
auto token = tokens.next_token();
if (token.is(Token::Type::Whitespace) || token.is(Token::Type::Semicolon)) {
continue;
}
if (token.is(Token::Type::EndOfFile)) {
return list;
}
if (token.is(Token::Type::AtKeyword)) {
tokens.reconsume_current_input_token();
list.append(DeclarationOrAtRule(consume_an_at_rule(tokens)));
continue;
}
if (token.is(Token::Type::Ident)) {
Vector<StyleComponentValueRule> temp;
temp.append(token);
for (;;) {
auto peek = tokens.peek_token();
if (peek.is(Token::Type::Semicolon) || peek.is(Token::Type::EndOfFile)) {
break;
}
temp.append(consume_a_component_value(tokens));
}
auto token_stream = TokenStream(temp);
auto maybe_declaration = consume_a_declaration(token_stream);
if (maybe_declaration.has_value()) {
list.append(DeclarationOrAtRule(maybe_declaration.value()));
}
continue;
}
log_parse_error();
tokens.reconsume_current_input_token();
auto peek = tokens.peek_token();
while (!(peek.is(Token::Type::Semicolon) || peek.is(Token::Type::EndOfFile))) {
dbgln("Discarding token: '{}'", peek.to_debug_string());
(void)consume_a_component_value(tokens);
peek = tokens.peek_token();
}
}
return list;
}
RefPtr<CSSRule> Parser::parse_as_rule()
{
return parse_as_rule(m_token_stream);
}
template<typename T>
RefPtr<CSSRule> Parser::parse_as_rule(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_rule");
RefPtr<CSSRule> rule;
tokens.skip_whitespace();
auto token = tokens.peek_token();
if (token.is(Token::Type::EndOfFile)) {
return {};
} else if (token.is(Token::Type::AtKeyword)) {
auto at_rule = consume_an_at_rule();
rule = convert_to_rule(at_rule);
} else {
auto qualified_rule = consume_a_qualified_rule(tokens);
if (!qualified_rule)
return {};
rule = convert_to_rule(*qualified_rule);
}
tokens.skip_whitespace();
auto maybe_eof = tokens.peek_token();
if (maybe_eof.is(Token::Type::EndOfFile)) {
return rule;
}
return {};
}
NonnullRefPtrVector<CSSRule> Parser::parse_as_list_of_rules()
{
return parse_as_list_of_rules(m_token_stream);
}
template<typename T>
NonnullRefPtrVector<CSSRule> Parser::parse_as_list_of_rules(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_list_of_rules");
auto parsed_rules = consume_a_list_of_rules(tokens, false);
NonnullRefPtrVector<CSSRule> rules;
for (auto& rule : parsed_rules) {
auto converted_rule = convert_to_rule(rule);
if (converted_rule)
rules.append(*converted_rule);
}
return rules;
}
Optional<StyleProperty> Parser::parse_as_declaration()
{
return parse_as_declaration(m_token_stream);
}
template<typename T>
Optional<StyleProperty> Parser::parse_as_declaration(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_declaration");
tokens.skip_whitespace();
auto token = tokens.peek_token();
if (!token.is(Token::Type::Ident)) {
return {};
}
auto declaration = consume_a_declaration(tokens);
if (declaration.has_value())
return convert_to_style_property(declaration.value());
return {};
}
RefPtr<CSSStyleDeclaration> Parser::parse_as_list_of_declarations()
{
return parse_as_list_of_declarations(m_token_stream);
}
template<typename T>
RefPtr<CSSStyleDeclaration> Parser::parse_as_list_of_declarations(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_list_of_declarations");
auto declarations_and_at_rules = consume_a_list_of_declarations(tokens);
Vector<StyleProperty> properties;
HashMap<String, StyleProperty> custom_properties;
for (auto& declaration_or_at_rule : declarations_and_at_rules) {
if (declaration_or_at_rule.is_at_rule()) {
dbgln("Parser::parse_as_list_of_declarations(): At-rule is not allowed here!");
continue;
}
auto& declaration = declaration_or_at_rule.m_declaration;
auto maybe_property = convert_to_style_property(declaration);
if (maybe_property.has_value()) {
auto property = maybe_property.value();
if (property.property_id == PropertyID::Custom) {
custom_properties.set(property.custom_name, property);
} else {
properties.append(property);
}
}
}
return CSSStyleDeclaration::create(move(properties), move(custom_properties));
}
Optional<StyleComponentValueRule> Parser::parse_as_component_value()
{
return parse_as_component_value(m_token_stream);
}
template<typename T>
Optional<StyleComponentValueRule> Parser::parse_as_component_value(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_component_value");
tokens.skip_whitespace();
auto token = tokens.peek_token();
if (token.is(Token::Type::EndOfFile)) {
return {};
}
auto value = consume_a_component_value(tokens);
tokens.skip_whitespace();
auto maybe_eof = tokens.peek_token();
if (maybe_eof.is(Token::Type::EndOfFile)) {
return value;
}
return {};
}
Vector<StyleComponentValueRule> Parser::parse_as_list_of_component_values()
{
return parse_as_list_of_component_values(m_token_stream);
}
template<typename T>
Vector<StyleComponentValueRule> Parser::parse_as_list_of_component_values(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_list_of_component_values");
Vector<StyleComponentValueRule> rules;
for (;;) {
if (tokens.peek_token().is(Token::Type::EndOfFile)) {
break;
}
rules.append(consume_a_component_value(tokens));
}
return rules;
}
Vector<Vector<StyleComponentValueRule>> Parser::parse_as_comma_separated_list_of_component_values()
{
return parse_as_comma_separated_list_of_component_values(m_token_stream);
}
template<typename T>
Vector<Vector<StyleComponentValueRule>> Parser::parse_as_comma_separated_list_of_component_values(TokenStream<T>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_as_comma_separated_list_of_component_values");
Vector<Vector<StyleComponentValueRule>> lists;
lists.append({});
for (;;) {
auto next = tokens.next_token();
if (next.is(Token::Type::Comma)) {
lists.append({});
continue;
} else if (next.is(Token::Type::EndOfFile)) {
break;
}
tokens.reconsume_current_input_token();
auto component_value = consume_a_component_value(tokens);
lists.last().append(component_value);
}
return lists;
}
RefPtr<CSSRule> Parser::convert_to_rule(NonnullRefPtr<StyleRule> rule)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::convert_to_rule");
if (rule->m_type == StyleRule::Type::At) {
if (rule->m_name.equals_ignoring_case("import"sv) && !rule->prelude().is_empty()) {
Optional<String> url;
auto url_token = rule->prelude().first();
if (url_token.is_function()) {
auto& function = url_token.function();
if (function.name().equals_ignoring_case("url"sv) && !function.values().is_empty()) {
auto& argument_token = url_token.function().values().first();
if (argument_token.is(Token::Type::String))
url = argument_token.token().string();
else
dbgln("First argument to url() was not a string: '{}'", argument_token.to_debug_string());
}
}
if (url_token.is(Token::Type::String))
url = url_token.token().string();
// FIXME: Handle list of media queries. https://www.w3.org/TR/css-cascade-3/#conditional-import
if (url.has_value())
return CSSImportRule::create(m_context.complete_url(url.value()));
} else {
dbgln("Unrecognized CSS at-rule: {}", rule->m_name);
}
// FIXME: More at rules!
} else {
auto prelude_stream = TokenStream(rule->m_prelude);
auto selectors = parse_a_selector(prelude_stream);
auto declaration = convert_to_declaration(*rule->m_block);
if (declaration && !selectors.is_empty())
return CSSStyleRule::create(move(selectors), move(*declaration));
else
dbgln("Discarding invalid/unsupported style rule: '{}'", rule->to_string());
}
return {};
}
RefPtr<CSSStyleDeclaration> Parser::convert_to_declaration(NonnullRefPtr<StyleBlockRule> block)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::convert_to_declaration");
if (!block->is_curly())
return {};
auto stream = TokenStream(block->m_values);
return parse_as_list_of_declarations(stream);
}
Optional<StyleProperty> Parser::convert_to_style_property(StyleDeclarationRule& declaration)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::convert_to_style_property");
auto& property_name = declaration.m_name;
auto property_id = property_id_from_string(property_name);
if (property_id == PropertyID::Invalid && property_name.starts_with("--"))
property_id = PropertyID::Custom;
if (property_id == PropertyID::Invalid && !property_name.starts_with("-")) {
dbgln("Parser::convert_to_style_property(): Unrecognized property '{}'", property_name);
return {};
}
auto value_token_stream = TokenStream(declaration.m_values);
auto value = parse_css_value(property_id, value_token_stream);
if (!value) {
dbgln("Parser::convert_to_style_property(): Property '{}' has no value.", property_name);
return {};
}
if (property_id == PropertyID::Custom) {
return StyleProperty { property_id, value.release_nonnull(), declaration.m_name, declaration.m_important };
} else {
return StyleProperty { property_id, value.release_nonnull(), {}, declaration.m_important };
}
}
Optional<float> Parser::try_parse_float(StringView string)
{
// FIXME: This is copied from DeprecatedCSSParser, so may not be to spec.
const char* str = string.characters_without_null_termination();
size_t len = string.length();
size_t weight = 1;
int exp_val = 0;
float value = 0.0f;
float fraction = 0.0f;
bool has_sign = false;
bool is_negative = false;
bool is_fractional = false;
bool is_scientific = false;
if (str[0] == '-') {
is_negative = true;
has_sign = true;
}
if (str[0] == '+') {
has_sign = true;
}
for (size_t i = has_sign; i < len; i++) {
// Looks like we're about to start working on the fractional part
if (str[i] == '.') {
is_fractional = true;
continue;
}
if (str[i] == 'e' || str[i] == 'E') {
if (str[i + 1] == '-' || str[i + 1] == '+')
exp_val = atoi(str + i + 2);
else
exp_val = atoi(str + i + 1);
is_scientific = true;
continue;
}
if (str[i] < '0' || str[i] > '9' || exp_val != 0) {
return {};
continue;
}
if (is_fractional) {
fraction *= 10;
fraction += str[i] - '0';
weight *= 10;
} else {
value = value * 10;
value += str[i] - '0';
}
}
fraction /= weight;
value += fraction;
if (is_scientific) {
bool divide = exp_val < 0;
if (divide)
exp_val *= -1;
for (int i = 0; i < exp_val; i++) {
if (divide)
value /= 10;
else
value *= 10;
}
}
return is_negative ? -value : value;
}
RefPtr<StyleValue> Parser::parse_css_value(PropertyID property_id, TokenStream<StyleComponentValueRule>& tokens)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_css_value");
// FIXME: This is mostly copied from the old, deprecated parser. It is probably not to spec.
auto takes_integer_value = [](PropertyID property_id) -> bool {
return property_id == PropertyID::ZIndex
|| property_id == PropertyID::FontWeight
|| property_id == PropertyID::Custom;
};
auto parse_length = [&]() -> Optional<Length> {
Length::Type type = Length::Type::Undefined;
Optional<float> numeric_value;
auto token = tokens.next_token();
if (token.is(Token::Type::Dimension)) {
auto length_string = token.token().m_value.string_view();
auto unit_string = token.token().m_unit.string_view();
if (unit_string.equals_ignoring_case("%")) {
type = Length::Type::Percentage;
} else if (unit_string.equals_ignoring_case("px")) {
type = Length::Type::Px;
} else if (unit_string.equals_ignoring_case("pt")) {
type = Length::Type::Pt;
} else if (unit_string.equals_ignoring_case("pc")) {
type = Length::Type::Pc;
} else if (unit_string.equals_ignoring_case("mm")) {
type = Length::Type::Mm;
} else if (unit_string.equals_ignoring_case("rem")) {
type = Length::Type::Rem;
} else if (unit_string.equals_ignoring_case("em")) {
type = Length::Type::Em;
} else if (unit_string.equals_ignoring_case("ex")) {
type = Length::Type::Ex;
} else if (unit_string.equals_ignoring_case("vw")) {
type = Length::Type::Vw;
} else if (unit_string.equals_ignoring_case("vh")) {
type = Length::Type::Vh;
} else if (unit_string.equals_ignoring_case("vmax")) {
type = Length::Type::Vmax;
} else if (unit_string.equals_ignoring_case("vmin")) {
type = Length::Type::Vmin;
} else if (unit_string.equals_ignoring_case("cm")) {
type = Length::Type::Cm;
} else if (unit_string.equals_ignoring_case("in")) {
type = Length::Type::In;
} else if (unit_string.equals_ignoring_case("Q")) {
type = Length::Type::Q;
} else if (m_context.in_quirks_mode()) {
type = Length::Type::Px;
}
numeric_value = try_parse_float(length_string);
} else if (token.is(Token::Type::Number)) {
auto value_string = token.token().m_value.string_view();
if (value_string == "0") {
type = Length::Type::Px;
numeric_value = 0;
} else if (m_context.in_quirks_mode()) {
type = Length::Type::Px;
numeric_value = try_parse_float(value_string);
}
}
if (!numeric_value.has_value())
return {};
return Length(numeric_value.value(), type);
};
auto token = tokens.next_token();
if (takes_integer_value(property_id) && token.is(Token::Type::Number)) {
auto number = token.token();
if (number.m_number_type == Token::NumberType::Integer) {
return LengthStyleValue::create(Length::make_px(number.integer()));
}
}
if (token.is(Token::Type::Dimension) || token.is(Token::Type::Number)) {
tokens.reconsume_current_input_token();
auto length = parse_length();
if (length.has_value())
return LengthStyleValue::create(length.value());
auto value_string = token.token().m_value.string_view();
auto float_number = try_parse_float(value_string);
if (float_number.has_value())
return NumericStyleValue::create(float_number.value());
return nullptr;
}
if (token.is(Token::Type::Ident)) {
auto ident = token.token().ident();
if (ident.equals_ignoring_case("inherit"))
return InheritStyleValue::create();
if (ident.equals_ignoring_case("initial"))
return InitialStyleValue::create();
if (ident.equals_ignoring_case("auto"))
return LengthStyleValue::create(Length::make_auto());
}
if (token.is_function() && token.function().name().equals_ignoring_case("var")) {
// FIXME: Handle fallback value as second parameter
// https://www.w3.org/TR/css-variables-1/#using-variables
if (!token.function().values().is_empty()) {
auto& property_name_token = token.function().values().first();
if (property_name_token.is(Token::Type::Ident))
return CustomStyleValue::create(property_name_token.token().ident());
else
dbgln("First argument to var() function was not an ident: '{}'", property_name_token.to_debug_string());
}
}
if (token.is(Token::Type::Ident)) {
auto value_id = value_id_from_string(token.token().ident());
if (value_id != ValueID::Invalid)
return IdentifierStyleValue::create(value_id);
}
auto parse_css_color = [&]() -> Optional<Color> {
if (token.is(Token::Type::Ident) && token.token().ident().equals_ignoring_case("transparent"))
return Color::from_rgba(0x00000000);
// FIXME: Handle all the different color notations.
// https://www.w3.org/TR/css-color-3/
// Right now, this uses non-CSS-specific parsing, and assumes the whole color value is one token,
// which is isn't if it's a function-style syntax.
auto color = Color::from_string(token.token().m_value.to_string().to_lowercase());
if (color.has_value())
return color;
return {};
};
auto color = parse_css_color();
if (color.has_value())
return ColorStyleValue::create(color.value());
if (token.is(Token::Type::String))
return StringStyleValue::create(token.token().string());
return {};
}
Optional<Selector::SimpleSelector::NthChildPattern> Parser::parse_nth_child_pattern(TokenStream<StyleComponentValueRule>& values)
{
dbgln_if(CSS_PARSER_TRACE, "Parser::parse_nth_child_pattern");
Selector::SimpleSelector::NthChildPattern pattern;
auto current_value = values.next_token();
if (current_value.is(Token::Type::Ident)) {
auto ident = current_value.token().ident();
if (ident.equals_ignoring_case("odd")) {
pattern.step_size = 2;
pattern.offset = 1;
return pattern;
} else if (ident.equals_ignoring_case("even")) {
pattern.step_size = 2;
return pattern;
}
}
// Try to match any of following patterns:
// 1. An+B
// 2. An
// 3. B
// ...where "A" is "step_size", "B" is "offset" and rest are literals.
// "A" can be omitted, in that case "A" = 1.
// "A" may have "+" or "-" sign, "B" always must be predated by sign for pattern (1).
auto is_n = [](StyleComponentValueRule value) -> bool {
return value.is(Token::Type::Ident) && value.token().ident().equals_ignoring_case("n");
};
auto is_delim = [](StyleComponentValueRule value, StringView delim) -> bool {
return value.is(Token::Type::Delim) && value.token().delim().equals_ignoring_case(delim);
};
int step_size_or_offset = 0;
// "When a=1, or a=-1, the 1 may be omitted from the rule."
if (is_n(current_value)) {
step_size_or_offset = +1;
} else if (is_delim(current_value, "+"sv) && is_n(values.peek_token())) {
step_size_or_offset = +1;
values.next_token();
} else if (is_delim(current_value, "-"sv) && is_n(values.peek_token())) {
step_size_or_offset = -1;
values.next_token();
} else if (current_value.is(Token::Type::Number)) {
step_size_or_offset = current_value.token().integer();
} else {
values.reconsume_current_input_token();
}
current_value = values.next_token();
if (is_n(current_value)) {
values.skip_whitespace();
auto next_value = values.peek_token();
if (is_delim(next_value, "+") || is_delim(next_value, "-")) {
const auto sign = is_delim(next_value, "+") ? 1 : -1;
values.next_token();
values.skip_whitespace();
// "An+B" pattern
auto number = values.next_token();
if (!number.is(Token::Type::Number))
return {};
pattern.step_size = step_size_or_offset;
pattern.offset = sign * number.token().integer();
} else {
// "An" pattern
pattern.step_size = step_size_or_offset;
}
} else {
// "B" pattern
pattern.offset = step_size_or_offset;
}
if (values.has_next_token())
return {};
return pattern;
}
}
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