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242 lines
12 KiB
C++
242 lines
12 KiB
C++
/*
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* Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibWeb/CSS/Parser/ErrorReporter.h>
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#include <LibWeb/CSS/Parser/Parser.h>
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#include <LibWeb/CSS/StyleValues/FontSourceStyleValue.h>
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#include <LibWeb/CSS/StyleValues/KeywordStyleValue.h>
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#include <LibWeb/CSS/StyleValues/LengthStyleValue.h>
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#include <LibWeb/CSS/StyleValues/PercentageStyleValue.h>
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#include <LibWeb/CSS/StyleValues/StringStyleValue.h>
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#include <LibWeb/CSS/StyleValues/StyleValueList.h>
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#include <LibWeb/CSS/StyleValues/UnicodeRangeStyleValue.h>
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#include <LibWeb/CSS/StyleValues/UnresolvedStyleValue.h>
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namespace Web::CSS::Parser {
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Parser::ParseErrorOr<NonnullRefPtr<StyleValue const>> Parser::parse_descriptor_value(AtRuleID at_rule_id, DescriptorID descriptor_id, TokenStream<ComponentValue>& unprocessed_tokens)
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{
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if (!at_rule_supports_descriptor(at_rule_id, descriptor_id)) {
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ErrorReporter::the().report(UnknownPropertyError {
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.rule_name = to_string(at_rule_id),
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.property_name = to_string(descriptor_id),
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});
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return ParseError::SyntaxError;
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}
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auto context_guard = push_temporary_value_parsing_context(DescriptorContext { at_rule_id, descriptor_id });
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Vector<ComponentValue> component_values;
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while (unprocessed_tokens.has_next_token()) {
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if (unprocessed_tokens.peek_token().is(Token::Type::Semicolon))
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break;
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auto const& token = unprocessed_tokens.consume_a_token();
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component_values.append(token);
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}
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TokenStream tokens { component_values };
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auto metadata = get_descriptor_metadata(at_rule_id, descriptor_id);
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for (auto const& option : metadata.syntax) {
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auto transaction = tokens.begin_transaction();
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auto parsed_style_value = option.visit(
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[&](Keyword keyword) {
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return parse_all_as_single_keyword_value(tokens, keyword);
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},
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[&](PropertyID property_id) -> RefPtr<StyleValue const> {
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auto value_or_error = parse_css_value(property_id, tokens);
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if (value_or_error.is_error())
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return nullptr;
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auto value_for_property = value_or_error.release_value();
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// Descriptors don't accept the following, which properties do:
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// - CSS-wide keywords
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// - Arbitrary substitution functions (so, UnresolvedStyleValue)
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if (value_for_property->is_css_wide_keyword() || value_for_property->is_unresolved())
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return nullptr;
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return value_for_property;
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},
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[&](DescriptorMetadata::ValueType value_type) -> RefPtr<StyleValue const> {
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switch (value_type) {
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case DescriptorMetadata::ValueType::CropOrCross: {
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// crop || cross
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auto first = parse_keyword_value(tokens);
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tokens.discard_whitespace();
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auto second = parse_keyword_value(tokens);
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if (!first)
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return nullptr;
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RefPtr<StyleValue const> crop;
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RefPtr<StyleValue const> cross;
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if (first->to_keyword() == Keyword::Crop)
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crop = first;
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else if (first->to_keyword() == Keyword::Cross)
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cross = first;
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else
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return nullptr;
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if (!second)
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return first.release_nonnull();
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if (crop.is_null() && second->to_keyword() == Keyword::Crop)
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crop = second.release_nonnull();
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else if (cross.is_null() && second->to_keyword() == Keyword::Cross)
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cross = second.release_nonnull();
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else
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return nullptr;
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return StyleValueList::create(StyleValueVector { crop.release_nonnull(), cross.release_nonnull() }, StyleValueList::Separator::Space);
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}
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case DescriptorMetadata::ValueType::FamilyName:
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return parse_family_name_value(tokens);
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case DescriptorMetadata::ValueType::FontSrcList: {
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// "If a component value is parsed correctly and is of a font format or font tech that the UA
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// supports, add it to the list of supported sources. If parsing a component value results in a
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// parsing error or its format or tech are unsupported, do not add it to the list of supported
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// sources.
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// If there are no supported entries at the end of this process, the value for the src descriptor
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// is a parse error.
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// These parsing rules allow for graceful fallback of fonts for user agents which don’t support a
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// particular font tech or font format."
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// https://drafts.csswg.org/css-fonts-4/#font-face-src-parsing
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auto source_lists = parse_a_comma_separated_list_of_component_values(tokens);
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StyleValueVector valid_sources;
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for (auto const& source_list : source_lists) {
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TokenStream source_tokens { source_list };
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if (auto font_source = parse_font_source_value(source_tokens); font_source && !source_tokens.has_next_token())
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valid_sources.append(font_source.release_nonnull());
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}
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if (valid_sources.is_empty())
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return nullptr;
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return StyleValueList::create(move(valid_sources), StyleValueList::Separator::Comma);
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}
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case DescriptorMetadata::ValueType::Length:
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return parse_length_value(tokens);
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case DescriptorMetadata::ValueType::OptionalDeclarationValue: {
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// `component_values` already has what we want. Just skip through its tokens so code below knows we consumed them.
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while (tokens.has_next_token())
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tokens.discard_a_token();
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return UnresolvedStyleValue::create(move(component_values));
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}
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case DescriptorMetadata::ValueType::PageSize: {
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// https://drafts.csswg.org/css-page-3/#page-size-prop
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// <length [0,∞]>{1,2} | auto | [ <page-size> || [ portrait | landscape ] ]
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// auto
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if (auto value = parse_all_as_single_keyword_value(tokens, Keyword::Auto))
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return value.release_nonnull();
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// <length [0,∞]>{1,2}
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if (auto first_length = parse_length_value(tokens)) {
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if (first_length->is_length() && first_length->as_length().raw_value() < 0)
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return nullptr;
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tokens.discard_whitespace();
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if (auto second_length = parse_length_value(tokens)) {
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if (second_length->is_length() && second_length->as_length().raw_value() < 0)
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return nullptr;
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return StyleValueList::create(StyleValueVector { first_length.release_nonnull(), second_length.release_nonnull() }, StyleValueList::Separator::Space);
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}
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return first_length.release_nonnull();
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}
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// [ <page-size> || [ portrait | landscape ] ]
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RefPtr<StyleValue const> page_size;
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RefPtr<StyleValue const> orientation;
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if (auto first_keyword = parse_keyword_value(tokens)) {
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if (first_is_one_of(first_keyword->to_keyword(), Keyword::Landscape, Keyword::Portrait)) {
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orientation = first_keyword.release_nonnull();
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} else if (keyword_to_page_size(first_keyword->to_keyword()).has_value()) {
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page_size = first_keyword.release_nonnull();
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} else {
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return nullptr;
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}
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} else {
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return nullptr;
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}
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tokens.discard_whitespace();
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if (auto second_keyword = parse_keyword_value(tokens)) {
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if (orientation.is_null() && first_is_one_of(second_keyword->to_keyword(), Keyword::Landscape, Keyword::Portrait)) {
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orientation = second_keyword.release_nonnull();
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} else if (page_size.is_null() && keyword_to_page_size(second_keyword->to_keyword()).has_value()) {
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page_size = second_keyword.release_nonnull();
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} else {
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return nullptr;
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}
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// Portrait is considered the default orientation, so don't include it.
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if (orientation->to_keyword() == Keyword::Portrait)
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return page_size.release_nonnull();
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return StyleValueList::create(StyleValueVector { page_size.release_nonnull(), orientation.release_nonnull() }, StyleValueList::Separator::Space);
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}
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return page_size ? page_size.release_nonnull() : orientation.release_nonnull();
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}
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case DescriptorMetadata::ValueType::PositivePercentage: {
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if (auto percentage_value = parse_percentage_value(tokens)) {
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if (percentage_value->is_percentage()) {
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if (percentage_value->as_percentage().raw_value() < 0)
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return nullptr;
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return percentage_value.release_nonnull();
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}
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// All calculations in descriptors must be resolvable at parse-time.
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if (percentage_value->is_calculated()) {
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auto percentage = percentage_value->as_calculated().resolve_percentage({});
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if (percentage.has_value() && percentage->value() >= 0)
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return PercentageStyleValue::create(percentage.release_value());
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return nullptr;
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}
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}
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return nullptr;
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}
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case DescriptorMetadata::ValueType::String:
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return parse_string_value(tokens);
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case DescriptorMetadata::ValueType::UnicodeRangeTokens: {
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return parse_comma_separated_value_list(tokens, [this](auto& tokens) -> RefPtr<StyleValue const> {
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return parse_unicode_range_value(tokens);
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});
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}
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}
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return nullptr;
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});
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if (!parsed_style_value || tokens.has_next_token())
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continue;
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transaction.commit();
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return parsed_style_value.release_nonnull();
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}
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ErrorReporter::the().report(InvalidPropertyError {
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.rule_name = to_string(at_rule_id),
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.property_name = to_string(descriptor_id),
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.value_string = tokens.dump_string(),
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.description = "Failed to parse."_string,
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});
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return ParseError::SyntaxError;
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}
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Optional<Descriptor> Parser::convert_to_descriptor(AtRuleID at_rule_id, Declaration const& declaration)
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{
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auto descriptor_id = descriptor_id_from_string(at_rule_id, declaration.name);
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if (!descriptor_id.has_value())
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return {};
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auto value_token_stream = TokenStream(declaration.value);
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auto value = parse_descriptor_value(at_rule_id, descriptor_id.value(), value_token_stream);
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if (value.is_error())
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return {};
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return Descriptor { *descriptor_id, value.release_value() };
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}
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}
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