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LibWeb: Only try parsing valid types of media-feature values

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This resolves the ambiguity between whether a single number is a number
or a ratio. :^)

Also removed the "no more tokens" checks from
deea129b8c - that logic was completely
wrong, since there are always tokens after a value in the `(123 < foo <
456)` syntax.
This commit is contained in:
Sam Atkins 2022-03-08 16:37:22 +00:00 • committed by Andreas Kling
parent 7ce8a91341
commit 56a36da44e
2 changed files with 65 additions and 29 deletions
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92
Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
View file

@ -932,7 +932,7 @@ Optional<MediaFeature> Parser::parse_media_feature(TokenStream<StyleComponentVal
tokens.skip_whitespace();
if (tokens.next_token().is(Token::Type::Colon)) {
tokens.skip_whitespace();
if (auto maybe_value = parse_media_feature_value(tokens); maybe_value.has_value()) {
if (auto maybe_value = parse_media_feature_value(maybe_name->id, tokens); maybe_value.has_value()) {
tokens.skip_whitespace();
if (!tokens.has_next_token()) {
switch (maybe_name->type) {
@ -1032,7 +1032,7 @@ Optional<MediaFeature> Parser::parse_media_feature(TokenStream<StyleComponentVal
tokens.skip_whitespace();
if (auto maybe_comparison = parse_comparison(tokens); maybe_comparison.has_value()) {
tokens.skip_whitespace();
if (auto maybe_value = parse_media_feature_value(tokens); maybe_value.has_value()) {
if (auto maybe_value = parse_media_feature_value(maybe_name->id, tokens); maybe_value.has_value()) {
tokens.skip_whitespace();
if (!tokens.has_next_token() && !maybe_value->is_ident())
return MediaFeature::half_range(maybe_value.release_value(), flip(maybe_comparison.release_value()), maybe_name->id);
@ -1043,11 +1043,31 @@ Optional<MediaFeature> Parser::parse_media_feature(TokenStream<StyleComponentVal
// `<mf-value> <mf-comparison> <mf-name>
// | <mf-value> <mf-lt> <mf-name> <mf-lt> <mf-value>
// | <mf-value> <mf-gt> <mf-name> <mf-gt> <mf-value>`
if (auto maybe_left_value = parse_media_feature_value(tokens); maybe_left_value.has_value()) {
tokens.skip_whitespace();
if (auto maybe_left_comparison = parse_comparison(tokens); maybe_left_comparison.has_value()) {
// NOTE: To parse the first value, we need to first find and parse the <mf-name> so we know what value types to parse.
// To allow for <mf-value> to be any number of tokens long, we scan forward until we find a comparison, and then
// treat the next non-whitespace token as the <mf-name>, which should be correct as long as they don't add a value
// type that can include a comparison in it. :^)
Optional<MediaFeatureName> maybe_name;
while (tokens.has_next_token() && !maybe_name.has_value()) {
if (auto maybe_comparison = parse_comparison(tokens); maybe_comparison.has_value()) {
// We found a comparison, so the next non-whitespace token should be the <mf-name>
tokens.skip_whitespace();
if (auto maybe_name = parse_mf_name(tokens, false); maybe_name.has_value() && media_feature_type_is_range(maybe_name->id)) {
maybe_name = parse_mf_name(tokens, false);
break;
}
tokens.next_token();
tokens.skip_whitespace();
}
tokens.rewind_to_position(position);
tokens.skip_whitespace();
// Now, we can parse the range properly.
if (maybe_name.has_value() && media_feature_type_is_range(maybe_name->id)) {
if (auto maybe_left_value = parse_media_feature_value(maybe_name->id, tokens); maybe_left_value.has_value()) {
tokens.skip_whitespace();
if (auto maybe_left_comparison = parse_comparison(tokens); maybe_left_comparison.has_value()) {
tokens.skip_whitespace();
tokens.next_token(); // The <mf-name> which we already parsed above.
tokens.skip_whitespace();
if (!tokens.has_next_token())
@ -1055,7 +1075,7 @@ Optional<MediaFeature> Parser::parse_media_feature(TokenStream<StyleComponentVal
if (auto maybe_right_comparison = parse_comparison(tokens); maybe_right_comparison.has_value()) {
tokens.skip_whitespace();
if (auto maybe_right_value = parse_media_feature_value(tokens); maybe_right_value.has_value()) {
if (auto maybe_right_value = parse_media_feature_value(maybe_name->id, tokens); maybe_right_value.has_value()) {
tokens.skip_whitespace();
// For this to be valid, the following must be true:
// - Comparisons must either both be >/>= or both be </<=.
@ -1166,38 +1186,54 @@ OwnPtr<MediaCondition> Parser::parse_media_in_parens(TokenStream<StyleComponentV
}
// `<mf-value>`, https://www.w3.org/TR/mediaqueries-4/#typedef-mf-value
Optional<MediaFeatureValue> Parser::parse_media_feature_value(TokenStream<StyleComponentValueRule>& tokens)
Optional<MediaFeatureValue> Parser::parse_media_feature_value(MediaFeatureID media_feature, TokenStream<StyleComponentValueRule>& tokens)
{
// `<number> | <dimension> | <ident> | <ratio>`
auto position = tokens.position();
tokens.skip_whitespace();
auto& first = tokens.next_token();
tokens.skip_whitespace();
// `<number>`
if (first.is(Token::Type::Number) && !tokens.has_next_token())
return MediaFeatureValue(first.token().number_value());
// `<dimension>`
if (auto dimension = parse_dimension(first); dimension.has_value() && !tokens.has_next_token()) {
if (dimension->is_length())
return MediaFeatureValue(dimension->length());
if (dimension->is_resolution())
return MediaFeatureValue(dimension->resolution());
}
// `<ident>`
// Identifiers
if (first.is(Token::Type::Ident)) {
if (auto ident = value_id_from_string(first.token().ident()); ident != ValueID::Invalid)
auto ident = value_id_from_string(first.token().ident());
if (ident != ValueID::Invalid && media_feature_accepts_identifier(media_feature, ident))
return MediaFeatureValue(ident);
}
// `<ratio>`
// Note that a single <number> is a valid <ratio>, but it gets parsed above as a <number>.
// This will get solved with directed parsing of values based on the media-feature.
// One branch for each member of the MediaFeatureValueType enum:
// Boolean (<mq-boolean> in the spec: a 1 or 0)
if (media_feature_accepts_type(media_feature, MediaFeatureValueType::Boolean)) {
if (first.is(Token::Type::Number) && first.token().number_type() == Token::NumberType::Integer
&& (first.token().number_value() == 0 || first.token().number_value() == 1))
return MediaFeatureValue(first.token().number_value());
}
// Integer
if (media_feature_accepts_type(media_feature, MediaFeatureValueType::Integer)) {
if (first.is(Token::Type::Number) && first.token().number_type() == Token::NumberType::Integer)
return MediaFeatureValue(first.token().number_value());
}
// Length
if (media_feature_accepts_type(media_feature, MediaFeatureValueType::Length)) {
if (auto length = parse_length(first); length.has_value())
return MediaFeatureValue(length.release_value());
}
// Resolution
if (media_feature_accepts_type(media_feature, MediaFeatureValueType::Resolution)) {
if (auto resolution = parse_dimension(first); resolution.has_value() && resolution->is_resolution())
return MediaFeatureValue(resolution->resolution());
}
// Ratio
// Done last because it uses multiple tokens.
tokens.rewind_to_position(position);
if (auto ratio = parse_ratio(tokens); ratio.has_value() && !tokens.has_next_token())
return MediaFeatureValue(ratio.release_value());
if (media_feature_accepts_type(media_feature, MediaFeatureValueType::Ratio)) {
if (auto ratio = parse_ratio(tokens); ratio.has_value())
return MediaFeatureValue(ratio.release_value());
}
tokens.rewind_to_position(position);
return {};

2
Userland/Libraries/LibWeb/CSS/Parser/Parser.h
View file

@ -309,7 +309,7 @@ private:
Optional<MediaFeature> parse_media_feature(TokenStream<StyleComponentValueRule>&);
Optional<MediaQuery::MediaType> parse_media_type(TokenStream<StyleComponentValueRule>&);
OwnPtr<MediaCondition> parse_media_in_parens(TokenStream<StyleComponentValueRule>&);
Optional<MediaFeatureValue> parse_media_feature_value(TokenStream<StyleComponentValueRule>&);
Optional<MediaFeatureValue> parse_media_feature_value(MediaFeatureID, TokenStream<StyleComponentValueRule>&);
OwnPtr<Supports::Condition> parse_supports_condition(TokenStream<StyleComponentValueRule>&);
Optional<Supports::InParens> parse_supports_in_parens(TokenStream<StyleComponentValueRule>&);