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LibWeb: Parse calc() values in new CSS Parser

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This is a port of the code from DeprecatedCSSParser, to work with CSS
Tokens and TokenStream. I've modified it as little as possible.
This commit is contained in:
Sam Atkins 2021-07-28 16:30:59 +01:00 • committed by Andreas Kling
parent 21c59efbb9
commit 23d869138f
2 changed files with 284 additions and 9 deletions
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280
Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
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@ -2,6 +2,7 @@
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020-2021, the SerenityOS developers.
* Copyright (c) 2021, Sam Atkins <atkinssj@gmail.com>
* Copyright (c) 2021, Tobias Christiansen <tobi@tobyase.de>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@ -1399,15 +1400,24 @@ RefPtr<StyleValue> Parser::parse_builtin_or_dynamic_value(ParsingContext const&
// FIXME: Implement `unset` keyword
}
if (component_value.is_function() && component_value.function().name().equals_ignoring_case("var")) {
// FIXME: Handle fallback value as second parameter
// https://www.w3.org/TR/css-variables-1/#using-variables
if (!component_value.function().values().is_empty()) {
auto& property_name_token = component_value.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 (component_value.is_function()) {
auto& function = component_value.function();
if (function.name().equals_ignoring_case("calc")) {
auto calc_expression = parse_calc_expression(context, function.values());
// FIXME: Either produce a string value of calc() here, or do so in CalculatedStyleValue::to_string().
if (calc_expression)
return CalculatedStyleValue::create("(FIXME:calc to string)", calc_expression.release_nonnull());
} else if (function.name().equals_ignoring_case("var")) {
// FIXME: Handle fallback value as second parameter
// https://www.w3.org/TR/css-variables-1/#using-variables
if (!component_value.function().values().is_empty()) {
auto& property_name_token = component_value.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());
}
}
}
@ -2130,4 +2140,256 @@ Optional<Selector::SimpleSelector::ANPlusBPattern> Parser::parse_a_n_plus_b_patt
return syntax_error();
}
OwnPtr<CalculatedStyleValue::CalcSum> Parser::parse_calc_expression(ParsingContext const& context, Vector<StyleComponentValueRule> const& values)
{
auto tokens = TokenStream(values);
return parse_calc_sum(context, tokens);
}
Optional<CalculatedStyleValue::CalcValue> Parser::parse_calc_value(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto current_token = tokens.next_token();
if (current_token.is_block() && current_token.block().is_paren()) {
auto block_values = TokenStream(current_token.block().values());
auto parsed_calc_sum = parse_calc_sum(context, block_values);
if (!parsed_calc_sum)
return {};
return (CalculatedStyleValue::CalcValue) { parsed_calc_sum.release_nonnull() };
}
if (current_token.is(Token::Type::Number)) {
auto try_the_number = try_parse_float(current_token.token().number_string_value());
if (try_the_number.has_value())
return (CalculatedStyleValue::CalcValue) { try_the_number.value() };
return {};
}
if (current_token.is(Token::Type::Dimension) || current_token.is(Token::Type::Percentage)) {
auto maybe_length = parse_length(context, current_token);
if (maybe_length.has_value() && !maybe_length.value().is_undefined())
return (CalculatedStyleValue::CalcValue) { maybe_length.value() };
return {};
}
return {};
}
OwnPtr<CalculatedStyleValue::CalcProductPartWithOperator> Parser::parse_calc_product_part_with_operator(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto product_with_operator = make<CalculatedStyleValue::CalcProductPartWithOperator>();
tokens.skip_whitespace();
auto& op_token = tokens.peek_token();
if (!op_token.is(Token::Type::Delim))
return nullptr;
auto op = op_token.token().delim();
if (op == "*"sv) {
tokens.next_token();
tokens.skip_whitespace();
product_with_operator->op = CalculatedStyleValue::CalcProductPartWithOperator::Multiply;
auto parsed_calc_value = parse_calc_value(context, tokens);
if (!parsed_calc_value.has_value())
return nullptr;
product_with_operator->value = { parsed_calc_value.release_value() };
} else if (op == "/"sv) {
tokens.next_token();
tokens.skip_whitespace();
product_with_operator->op = CalculatedStyleValue::CalcProductPartWithOperator::Divide;
auto parsed_calc_number_value = parse_calc_number_value(context, tokens);
if (!parsed_calc_number_value.has_value())
return nullptr;
product_with_operator->value = { parsed_calc_number_value.release_value() };
} else {
return nullptr;
}
return product_with_operator;
}
OwnPtr<CalculatedStyleValue::CalcNumberProductPartWithOperator> Parser::parse_calc_number_product_part_with_operator(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto number_product_with_operator = make<CalculatedStyleValue::CalcNumberProductPartWithOperator>();
tokens.skip_whitespace();
auto& op_token = tokens.peek_token();
if (!op_token.is(Token::Type::Delim))
return nullptr;
auto op = op_token.token().delim();
if (op == "*"sv) {
tokens.next_token();
tokens.skip_whitespace();
number_product_with_operator->op = CalculatedStyleValue::CalcNumberProductPartWithOperator::Multiply;
} else if (op == "/"sv) {
tokens.next_token();
tokens.skip_whitespace();
number_product_with_operator->op = CalculatedStyleValue::CalcNumberProductPartWithOperator::Divide;
} else {
return nullptr;
}
auto parsed_calc_value = parse_calc_number_value(context, tokens);
if (!parsed_calc_value.has_value())
return nullptr;
number_product_with_operator->value = parsed_calc_value.release_value();
return number_product_with_operator;
}
OwnPtr<CalculatedStyleValue::CalcNumberProduct> Parser::parse_calc_number_product(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto calc_number_product = make<CalculatedStyleValue::CalcNumberProduct>();
auto first_calc_number_value_or_error = parse_calc_number_value(context, tokens);
if (!first_calc_number_value_or_error.has_value())
return nullptr;
calc_number_product->first_calc_number_value = first_calc_number_value_or_error.release_value();
while (tokens.has_next_token()) {
auto number_product_with_operator = parse_calc_number_product_part_with_operator(context, tokens);
if (!number_product_with_operator)
break;
calc_number_product->zero_or_more_additional_calc_number_values.append(number_product_with_operator.release_nonnull());
}
return calc_number_product;
}
OwnPtr<CalculatedStyleValue::CalcNumberSumPartWithOperator> Parser::parse_calc_number_sum_part_with_operator(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
if (!(tokens.peek_token().is(Token::Type::Delim)
&& tokens.peek_token().token().delim().is_one_of("+"sv, "-"sv)
&& tokens.peek_token(1).is(Token::Type::Whitespace)))
return nullptr;
auto& token = tokens.next_token();
tokens.skip_whitespace();
CalculatedStyleValue::CalcNumberSumPartWithOperator::Operation op;
auto delim = token.token().delim();
if (delim == "+"sv)
op = CalculatedStyleValue::CalcNumberSumPartWithOperator::Operation::Add;
else if (delim == "-"sv)
op = CalculatedStyleValue::CalcNumberSumPartWithOperator::Operation::Subtract;
else
return nullptr;
auto calc_number_product = parse_calc_number_product(context, tokens);
if (!calc_number_product)
return nullptr;
return make<CalculatedStyleValue::CalcNumberSumPartWithOperator>(op, calc_number_product.release_nonnull());
}
OwnPtr<CalculatedStyleValue::CalcNumberSum> Parser::parse_calc_number_sum(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto first_calc_number_product_or_error = parse_calc_number_product(context, tokens);
if (!first_calc_number_product_or_error)
return nullptr;
NonnullOwnPtrVector<CalculatedStyleValue::CalcNumberSumPartWithOperator> additional {};
while (tokens.has_next_token()) {
auto calc_sum_part = parse_calc_number_sum_part_with_operator(context, tokens);
if (!calc_sum_part)
return nullptr;
additional.append(calc_sum_part.release_nonnull());
}
tokens.skip_whitespace();
auto calc_number_sum = make<CalculatedStyleValue::CalcNumberSum>(first_calc_number_product_or_error.release_nonnull(), move(additional));
return calc_number_sum;
}
Optional<CalculatedStyleValue::CalcNumberValue> Parser::parse_calc_number_value(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto& first = tokens.peek_token();
if (first.is_block() && first.block().is_paren()) {
tokens.next_token();
auto block_values = TokenStream(first.block().values());
auto calc_number_sum = parse_calc_number_sum(context, block_values);
if (calc_number_sum)
return { calc_number_sum.release_nonnull() };
}
if (!first.is(Token::Type::Number))
return {};
tokens.next_token();
auto try_the_number = try_parse_float(first.token().number_string_value());
if (!try_the_number.has_value())
return {};
return try_the_number.value();
}
OwnPtr<CalculatedStyleValue::CalcProduct> Parser::parse_calc_product(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto calc_product = make<CalculatedStyleValue::CalcProduct>();
auto first_calc_value_or_error = parse_calc_value(context, tokens);
if (!first_calc_value_or_error.has_value())
return nullptr;
calc_product->first_calc_value = first_calc_value_or_error.release_value();
while (tokens.has_next_token()) {
auto product_with_operator = parse_calc_product_part_with_operator(context, tokens);
if (!product_with_operator)
break;
calc_product->zero_or_more_additional_calc_values.append(product_with_operator.release_nonnull());
}
return calc_product;
}
OwnPtr<CalculatedStyleValue::CalcSumPartWithOperator> Parser::parse_calc_sum_part_with_operator(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
// The following has to have the shape of <Whitespace><+ or -><Whitespace>
// But the first whitespace gets eaten in parse_calc_product_part_with_operator().
if (!(tokens.peek_token().is(Token::Type::Delim)
&& tokens.peek_token().token().delim().is_one_of("+"sv, "-"sv)
&& tokens.peek_token(1).is(Token::Type::Whitespace)))
return nullptr;
auto& token = tokens.next_token();
tokens.skip_whitespace();
CalculatedStyleValue::CalcSumPartWithOperator::Operation op;
auto delim = token.token().delim();
if (delim == "+"sv)
op = CalculatedStyleValue::CalcSumPartWithOperator::Operation::Add;
else if (delim == "-"sv)
op = CalculatedStyleValue::CalcSumPartWithOperator::Operation::Subtract;
else
return nullptr;
auto calc_product = parse_calc_product(context, tokens);
if (!calc_product)
return nullptr;
return make<CalculatedStyleValue::CalcSumPartWithOperator>(op, calc_product.release_nonnull());
};
OwnPtr<CalculatedStyleValue::CalcSum> Parser::parse_calc_sum(ParsingContext const& context, TokenStream<StyleComponentValueRule>& tokens)
{
auto parsed_calc_product = parse_calc_product(context, tokens);
if (!parsed_calc_product)
return nullptr;
NonnullOwnPtrVector<CalculatedStyleValue::CalcSumPartWithOperator> additional {};
while (tokens.has_next_token()) {
auto calc_sum_part = parse_calc_sum_part_with_operator(context, tokens);
if (!calc_sum_part)
return nullptr;
additional.append(calc_sum_part.release_nonnull());
}
tokens.skip_whitespace();
return make<CalculatedStyleValue::CalcSum>(parsed_calc_product.release_nonnull(), move(additional));
}
}