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// Copyright 2015 The Chromium Authors. All rights reserved.
// Copyright (C) 2016-2024 Apple Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "config.h"
#include "CSSSupportsParser.h"
#include "CSSParserImpl.h"
#include "CSSPropertyParserConsumer+Font.h"
#include "CSSSelectorParser.h"
#include "CSSTokenizer.h"
#include "FontCustomPlatformData.h"
#include "StyleRule.h"
namespace WebCore {
CSSSupportsParser::SupportsResult CSSSupportsParser::supportsCondition(CSSParserTokenRange range, CSSParserImpl& parser, ParsingMode mode)
{
// FIXME: The spec allows leading whitespace in @supports but not CSS.supports,
// but major browser vendors allow it in CSS.supports also.
range.consumeWhitespace();
CSSSupportsParser supportsParser(parser);
auto result = supportsParser.consumeCondition(range);
if (mode != ParsingMode::AllowBareDeclarationAndGeneralEnclosed || result != Invalid)
return result;
// window.CSS.supports requires parsing as-if the condition was wrapped in
// parenthesis. The only productions that wouldn't have parsed above are the
// declaration condition or the general enclosed productions.
return supportsParser.consumeSupportsFeatureOrGeneralEnclosed(range);
}
enum class ClauseType { Unresolved, Conjunction, Disjunction };
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeCondition(CSSParserTokenRange range)
{
if (range.peek().type() == IdentToken) {
if (equalLettersIgnoringASCIICase(range.peek().value(), "not"_s))
return consumeNegation(range);
}
bool result = false;
auto clauseType = ClauseType::Unresolved;
auto previousTokenType = IdentToken;
while (true) {
auto nextResult = consumeConditionInParenthesis(range, previousTokenType);
if (nextResult == Invalid)
return Invalid;
bool nextSupported = nextResult;
if (clauseType == ClauseType::Unresolved)
result = nextSupported;
else if (clauseType == ClauseType::Conjunction)
result &= nextSupported;
else
result |= nextSupported;
if (range.atEnd())
break;
range.consumeWhitespace();
if (range.atEnd())
break;
const CSSParserToken& token = range.peek();
if (token.type() != IdentToken)
return Invalid;
previousTokenType = token.type();
if (clauseType == ClauseType::Unresolved)
clauseType = token.value().length() == 3 ? ClauseType::Conjunction : ClauseType::Disjunction;
if ((clauseType == ClauseType::Conjunction && !equalLettersIgnoringASCIICase(token.value(), "and"_s))
|| (clauseType == ClauseType::Disjunction && !equalLettersIgnoringASCIICase(token.value(), "or"_s)))
return Invalid;
range.consume();
if (!CSSTokenizer::isWhitespace(range.peek().type()))
return Invalid;
range.consumeWhitespace();
}
return result ? Supported : Unsupported;
}
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeNegation(CSSParserTokenRange range)
{
ASSERT(range.peek().type() == IdentToken);
auto tokenType = range.peek().type();
if (range.peek().type() == IdentToken)
range.consume();
if (!CSSTokenizer::isWhitespace(range.peek().type()))
return Invalid;
range.consumeWhitespace();
auto result = consumeConditionInParenthesis(range, tokenType);
range.consumeWhitespace();
if (!range.atEnd() || result == Invalid)
return Invalid;
return result ? Unsupported : Supported;
}
// <function-token> <any-value>? | <supports-selector-fn> | <supports-font-format-fn> | <supports-font-tech-fn>
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeSupportsFunction(CSSParserTokenRange& range)
{
if (range.peek().type() != FunctionToken)
return Invalid;
switch (range.peek().functionId()) {
case CSSValueSelector:
return consumeSupportsSelectorFunction(range);
case CSSValueFontFormat:
return consumeSupportsFontFormatFunction(range);
case CSSValueFontTech:
return consumeSupportsFontTechFunction(range);
default: // Unknown functions should parse as unsupported.
range.consumeComponentValue();
return Unsupported;
}
}
// <supports-feature> | <general-enclosed>
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeSupportsFeatureOrGeneralEnclosed(CSSParserTokenRange& range)
{
if (range.peek().type() == FunctionToken) {
if (auto result = consumeSupportsFunction(range); result != Invalid)
return result;
}
return range.peek().type() == IdentToken && m_parser.supportsDeclaration(range) ? Supported : Unsupported;
}
// <supports-selector-fn>
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeSupportsSelectorFunction(CSSParserTokenRange& range)
{
ASSERT(range.peek().type() == FunctionToken && range.peek().functionId() == CSSValueSelector);
auto block = range.consumeBlock();
block.consumeWhitespace();
return CSSSelectorParser::supportsComplexSelector(block, m_parser.context()) ? Supported : Unsupported;
}
// <supports-font-format-fn>
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeSupportsFontFormatFunction(CSSParserTokenRange& range)
{
ASSERT(range.peek().type() == FunctionToken && range.peek().functionId() == CSSValueFontFormat);
auto format = CSSPropertyParserHelpers::consumeFontFormat(range, m_parser.context(), true);
if (format.isNull())
return Unsupported;
return FontCustomPlatformData::supportsFormat(format) ? Supported : Unsupported;
}
// <supports-font-tech-fn>
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeSupportsFontTechFunction(CSSParserTokenRange& range)
{
ASSERT(range.peek().type() == FunctionToken && range.peek().functionId() == CSSValueFontTech);
auto technologies = CSSPropertyParserHelpers::consumeFontTech(range, m_parser.context(), true);
if (technologies.isEmpty())
return Unsupported;
ASSERT(technologies.size() == 1);
return FontCustomPlatformData::supportsTechnology(technologies[0]) ? Supported : Unsupported;
}
// <supports-in-parens> = ( <supports-condition> ) | <supports-feature> | <general-enclosed>
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeConditionInParenthesis(CSSParserTokenRange& range, CSSParserTokenType startTokenType)
{
if (startTokenType == IdentToken && range.peek().type() != LeftParenthesisToken) {
if (auto result = consumeSupportsFunction(range); result != Invalid)
return result;
return Invalid;
}
auto innerRange = range.consumeBlock();
innerRange.consumeWhitespace();
if (auto result = consumeCondition(innerRange); result != Invalid)
return result;
return consumeSupportsFeatureOrGeneralEnclosed(innerRange);
}
} // namespace WebCore
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