Source/WebCore/css/calc/CSSCalcExpressionNodeParser.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2021 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 "CSSCalcExpressionNodeParser.h"

 #include "CSSCalcCategoryMapping.h"
 #include "CSSCalcInvertNode.h"
 #include "CSSCalcNegateNode.h"
 #include "CSSCalcOperationNode.h"
 #include "CSSCalcPrimitiveValueNode.h"
 #include "CSSCalcSymbolTable.h"
 #include "CSSCalcValue.h"
 #include "CSSParserToken.h"
 #include "CSSParserTokenRange.h"
 #include "CSSPropertyParserHelpers.h"
 #include "Logging.h"
 #include <wtf/text/TextStream.h>

 namespace WebCore {

 static constexpr int maxExpressionDepth = 100;

 // <https://drafts.csswg.org/css-values-4/#calc-syntax>:
 // <calc()>  = calc( <calc-sum> )
 // <min()>   = min( <calc-sum># )
 // <max()>   = max( <calc-sum># )
 // <clamp()> = clamp( <calc-sum>#{3} )
 // <sin()>   = sin( <calc-sum> )
 // <cos()>   = cos( <calc-sum> )
 // <tan()>   = tan( <calc-sum> )
 // <asin()>  = asin( <calc-sum> )
 // <acos()>  = acos( <calc-sum> )
 // <atan()>  = atan( <calc-sum> )
 // <atan2()> = atan2( <calc-sum>, <calc-sum> )
 // <pow()>   = pow( <calc-sum>, <calc-sum> )
 // <sqrt()>  = sqrt( <calc-sum> )
 // <hypot()> = hypot( <calc-sum># )
 // <calc-sum> = <calc-product> [ [ '+' | '-' ] <calc-product> ]*
 // <calc-product> = <calc-value> [ [ '*' | '/' ] <calc-value> ]*
 // <calc-value> = <number> | <dimension> | <percentage> | ( <calc-sum> )
 RefPtr<CSSCalcExpressionNode> CSSCalcExpressionNodeParser::parseCalc(CSSParserTokenRange tokens, CSSValueID function)
 {
     tokens.consumeWhitespace();

     RefPtr<CSSCalcExpressionNode> result;
     bool ok = parseCalcFunction(tokens, function, 0, result);
     if (!ok || !tokens.atEnd())
         return nullptr;

     if (!result)
         return nullptr;

     LOG_WITH_STREAM(Calc, stream << "CSSCalcExpressionNodeParser::parseCalc " << prettyPrintNode(*result));

     result = CSSCalcOperationNode::simplify(result.releaseNonNull());

     LOG_WITH_STREAM(Calc, stream << "CSSCalcExpressionNodeParser::parseCalc - after simplification " << prettyPrintNode(*result));

     return result;
 }

 char CSSCalcExpressionNodeParser::operatorValue(const CSSParserToken& token)
 {
     if (token.type() == DelimiterToken)
         return token.delimiter();
     return 0;
 }

 enum ParseState {
     OK,
     TooDeep,
     NoMoreTokens
 };

 static const CSSCalcSymbolTable getConstantTable()
 {
     return {
         { CSSValuePi, CSSUnitType::CSS_NUMBER, piDouble }, { CSSValueE, CSSUnitType::CSS_NUMBER, std::exp(1.0) },
         { CSSValueNegativeInfinity, CSSUnitType::CSS_NUMBER, -1 * std::numeric_limits<double>::infinity() },
         { CSSValueInfinity, CSSUnitType::CSS_NUMBER, std::numeric_limits<double>::infinity() },
         { CSSValueNaN, CSSUnitType::CSS_NUMBER, std::numeric_limits<double>::quiet_NaN() },
     };
 }

 static ParseState checkDepthAndIndex(int depth, CSSParserTokenRange tokens)
 {
     if (tokens.atEnd())
         return NoMoreTokens;
     if (depth > maxExpressionDepth) {
         LOG_WITH_STREAM(Calc, stream << "Depth " << depth << " exceeded maxExpressionDepth " << maxExpressionDepth);
         return TooDeep;
     }
     return OK;
 }

 bool CSSCalcExpressionNodeParser::parseCalcFunction(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
 {
     if (checkDepthAndIndex(depth, tokens) != OK)
         return false;

     // "arguments" refers to things between commas.
     unsigned minArgumentCount = 1;
     std::optional<unsigned> maxArgumentCount;

     switch (functionID) {
     case CSSValueMin:
     case CSSValueMax:
     case CSSValueHypot:
         maxArgumentCount = std::nullopt;
         break;
     case CSSValueClamp:
         minArgumentCount = 3;
         maxArgumentCount = 3;
         break;
     case CSSValueLog:
         maxArgumentCount = 2;
         break;
     case CSSValueRound:
         minArgumentCount = 2;
         maxArgumentCount = 3;
         break;
     case CSSValueMod:
     case CSSValueRem:
         minArgumentCount = 2;
         maxArgumentCount = 2;
         break;
     case CSSValueExp:
     case CSSValueSin:
     case CSSValueCos:
     case CSSValueTan:
     case CSSValueAcos:
     case CSSValueAsin:
     case CSSValueAtan:
     case CSSValueSign:
     case CSSValueAbs:
     case CSSValueCalc:
         maxArgumentCount = 1;
         break;
     case CSSValueAtan2:
         maxArgumentCount = 2;
         break;
     case CSSValuePow:
         minArgumentCount = 2;
         maxArgumentCount = 2;
         break;
     case CSSValueSqrt:
         maxArgumentCount = 1;
         break;
     default:
         break;
     }

     Vector<Ref<CSSCalcExpressionNode>> nodes;

     bool requireComma = false;
     unsigned argumentCount = 0;
     while (!tokens.atEnd()) {
         tokens.consumeWhitespace();
         if (requireComma && !CSSPropertyParserHelpers::consumeCommaIncludingWhitespace(tokens))
             return false;

         RefPtr<CSSCalcExpressionNode> node;
         if (!parseCalcSum(tokens, functionID, depth, node))
             return false;

         ++argumentCount;
         if (maxArgumentCount && argumentCount > maxArgumentCount.value())
             return false;

         nodes.append(node.releaseNonNull());
         requireComma = true;
     }

     if (argumentCount < minArgumentCount)
         return false;

     switch (functionID) {
     case CSSValueMin:
         result = CSSCalcOperationNode::createMinOrMaxOrClamp(CalcOperator::Min, WTFMove(nodes), m_destinationCategory);
         break;
     case CSSValueMax:
         result = CSSCalcOperationNode::createMinOrMaxOrClamp(CalcOperator::Max, WTFMove(nodes), m_destinationCategory);
         break;
     case CSSValueClamp:
         result = CSSCalcOperationNode::createMinOrMaxOrClamp(CalcOperator::Clamp, WTFMove(nodes), m_destinationCategory);
         break;
     case CSSValueSin:
         result = CSSCalcOperationNode::createTrig(CalcOperator::Sin, WTFMove(nodes));
         break;
     case CSSValueCos:
         result = CSSCalcOperationNode::createTrig(CalcOperator::Cos, WTFMove(nodes));
         break;
     case CSSValueTan:
         result = CSSCalcOperationNode::createTrig(CalcOperator::Tan, WTFMove(nodes));
         break;
     case CSSValueRound:
         result = CSSCalcOperationNode::createRound(WTFMove(nodes));
         break;
     case CSSValueMod:
         result = CSSCalcOperationNode::createStep(CalcOperator::Mod, WTFMove(nodes));
         break;
     case CSSValueRem:
         result = CSSCalcOperationNode::createStep(CalcOperator::Rem, WTFMove(nodes));
         break;
     case CSSValueWebkitCalc:
     case CSSValueCalc:
         result = CSSCalcOperationNode::createSum(WTFMove(nodes));
         break;
     case CSSValueLog:
         result = CSSCalcOperationNode::createLog(WTFMove(nodes));
         break;
     case CSSValueExp:
         result = CSSCalcOperationNode::createExp(WTFMove(nodes));
         break;
     case CSSValueAcos:
         result = CSSCalcOperationNode::createInverseTrig(CalcOperator::Acos, WTFMove(nodes));
         break;
     case CSSValueAsin:
         result = CSSCalcOperationNode::createInverseTrig(CalcOperator::Asin, WTFMove(nodes));
         break;
     case CSSValueAtan:
         result = CSSCalcOperationNode::createInverseTrig(CalcOperator::Atan, WTFMove(nodes));
         break;
     case CSSValueAtan2:
         result = CSSCalcOperationNode::createAtan2(WTFMove(nodes));
         break;
     case CSSValueAbs:
         result = CSSCalcOperationNode::createSign(CalcOperator::Abs, WTFMove(nodes));
         break;
     case CSSValueSign:
         result = CSSCalcOperationNode::createSign(CalcOperator::Sign, WTFMove(nodes));
         break;
     case CSSValuePow:
         result = CSSCalcOperationNode::createPowOrSqrt(CalcOperator::Pow, WTFMove(nodes));
         break;
     case CSSValueSqrt:
         result = CSSCalcOperationNode::createPowOrSqrt(CalcOperator::Sqrt, WTFMove(nodes));
         break;
     case CSSValueHypot:
         result = CSSCalcOperationNode::createHypot(WTFMove(nodes));
         break;
     default:
         break;
     }

     return !!result;
 }

 static bool checkRoundKeyword(CSSValueID functionID, RefPtr<CSSCalcExpressionNode>& result, CSSValueID constantID)
 {
     if (functionID != CSSValueRound)
         return false;
     switch (constantID) {
     case CSSValueNearest:
         result = CSSCalcOperationNode::createRoundConstant(CalcOperator::Nearest);
         return true;
     case CSSValueToZero:
         result = CSSCalcOperationNode::createRoundConstant(CalcOperator::ToZero);
         return true;
     case CSSValueUp:
         result = CSSCalcOperationNode::createRoundConstant(CalcOperator::Up);
         return true;
     case CSSValueDown:
         result = CSSCalcOperationNode::createRoundConstant(CalcOperator::Down);
         return true;
     default:
         return false;
     }
 }

 bool CSSCalcExpressionNodeParser::parseValue(CSSParserTokenRange& tokens, CSSValueID functionID, RefPtr<CSSCalcExpressionNode>& result)
 {
     auto makeCSSCalcPrimitiveValueNode = [&] (CSSUnitType type, double value) -> bool {
         if (calcUnitCategory(type) == CalculationCategory::Other)
             return false;

         result = CSSCalcPrimitiveValueNode::create(CSSPrimitiveValue::create(value, type));
         return true;
     };

     auto token = tokens.consumeIncludingWhitespace();

     switch (token.type()) {
     case IdentToken: {
         if (checkRoundKeyword(functionID, result, token.id()))
             return true;
         auto value = m_symbolTable.get(token.id());
         value = value ? value : getConstantTable().get(token.id());
         if (!value)
             return false;
         return makeCSSCalcPrimitiveValueNode(value->type, value->value);
     }

     case NumberToken:
     case PercentageToken:
     case DimensionToken:
         return makeCSSCalcPrimitiveValueNode(token.unitType(), token.numericValue());

     default:
         return false;
     }

     ASSERT_NOT_REACHED();
     return false;
 }

 bool CSSCalcExpressionNodeParser::parseCalcValue(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
 {
     if (checkDepthAndIndex(depth, tokens) != OK)
         return false;

     auto findFunctionId = [&](CSSValueID& functionId) {
         if (tokens.peek().type() == LeftParenthesisToken) {
             functionId = CSSValueCalc;
             return true;
         }

         functionId = tokens.peek().functionId();
         return CSSCalcValue::isCalcFunction(functionId);
     };

     CSSValueID functionId;
     if (findFunctionId(functionId)) {
         CSSParserTokenRange innerRange = tokens.consumeBlock();
         tokens.consumeWhitespace();
         innerRange.consumeWhitespace();
         return parseCalcFunction(innerRange, functionId, depth + 1, result);
     }

     return parseValue(tokens, functionID, result);
 }

 bool CSSCalcExpressionNodeParser::parseCalcProduct(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
 {
     if (checkDepthAndIndex(depth, tokens) != OK)
         return false;

     RefPtr<CSSCalcExpressionNode> firstValue;
     if (!parseCalcValue(tokens, functionID, depth, firstValue))
         return false;

     Vector<Ref<CSSCalcExpressionNode>> nodes;

     while (!tokens.atEnd()) {
         char operatorCharacter = operatorValue(tokens.peek());
         if (operatorCharacter != static_cast<char>(CalcOperator::Multiply) && operatorCharacter != static_cast<char>(CalcOperator::Divide))
             break;
         tokens.consumeIncludingWhitespace();

         RefPtr<CSSCalcExpressionNode> nextValue;
         if (!parseCalcValue(tokens, functionID, depth, nextValue) || !nextValue)
             return false;

         if (operatorCharacter == static_cast<char>(CalcOperator::Divide))
             nextValue = CSSCalcInvertNode::create(nextValue.releaseNonNull());

         if (firstValue)
             nodes.append(firstValue.releaseNonNull());

         nodes.append(nextValue.releaseNonNull());
     }

     if (nodes.isEmpty()) {
         result = WTFMove(firstValue);
         return !!result;
     }

     result = CSSCalcOperationNode::createProduct(WTFMove(nodes));
     return !!result;
 }

 bool CSSCalcExpressionNodeParser::parseCalcSum(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
 {
     if (checkDepthAndIndex(depth, tokens) != OK)
         return false;

     RefPtr<CSSCalcExpressionNode> firstValue;
     if (!parseCalcProduct(tokens, functionID, depth, firstValue))
         return false;

     Vector<Ref<CSSCalcExpressionNode>> nodes;

     while (!tokens.atEnd()) {
         char operatorCharacter = operatorValue(tokens.peek());
         if (operatorCharacter != static_cast<char>(CalcOperator::Add) && operatorCharacter != static_cast<char>(CalcOperator::Subtract))
             break;

         if ((&tokens.peek() - 1)->type() != WhitespaceToken)
             return false; // calc(1px+ 2px) is invalid

         tokens.consume();
         if (tokens.peek().type() != WhitespaceToken)
             return false; // calc(1px +2px) is invalid

         tokens.consumeIncludingWhitespace();

         RefPtr<CSSCalcExpressionNode> nextValue;
         if (!parseCalcProduct(tokens, functionID, depth, nextValue) || !nextValue)
             return false;

         if (operatorCharacter == static_cast<char>(CalcOperator::Subtract))
             nextValue = CSSCalcNegateNode::create(nextValue.releaseNonNull());

         if (firstValue)
             nodes.append(firstValue.releaseNonNull());

         nodes.append(nextValue.releaseNonNull());
     }

     if (nodes.isEmpty()) {
         result = WTFMove(firstValue);
         return !!result;
     }

     result = CSSCalcOperationNode::createSum(WTFMove(nodes));
     return !!result;
 }

 }
	/*
	* Copyright (C) 2021 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:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. 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.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 "CSSCalcExpressionNodeParser.h"

	#include "CSSCalcCategoryMapping.h"
	#include "CSSCalcInvertNode.h"
	#include "CSSCalcNegateNode.h"
	#include "CSSCalcOperationNode.h"
	#include "CSSCalcPrimitiveValueNode.h"
	#include "CSSCalcSymbolTable.h"
	#include "CSSCalcValue.h"
	#include "CSSParserToken.h"
	#include "CSSParserTokenRange.h"
	#include "CSSPropertyParserHelpers.h"
	#include "Logging.h"
	#include <wtf/text/TextStream.h>

	namespace WebCore {

	static constexpr int maxExpressionDepth = 100;

	// <https://drafts.csswg.org/css-values-4/#calc-syntax>:
	// <calc()> = calc( <calc-sum> )
	// <min()> = min( <calc-sum># )
	// <max()> = max( <calc-sum># )
	// <clamp()> = clamp( <calc-sum>#{3} )
	// <sin()> = sin( <calc-sum> )
	// <cos()> = cos( <calc-sum> )
	// <tan()> = tan( <calc-sum> )
	// <asin()> = asin( <calc-sum> )
	// <acos()> = acos( <calc-sum> )
	// <atan()> = atan( <calc-sum> )
	// <atan2()> = atan2( <calc-sum>, <calc-sum> )
	// <pow()> = pow( <calc-sum>, <calc-sum> )
	// <sqrt()> = sqrt( <calc-sum> )
	// <hypot()> = hypot( <calc-sum># )
	// <calc-sum> = <calc-product> [ [ '+' \| '-' ] <calc-product> ]*
	// <calc-product> = <calc-value> [ [ '' \| '/' ] <calc-value> ]
	// <calc-value> = <number> \| <dimension> \| <percentage> \| ( <calc-sum> )
	RefPtr<CSSCalcExpressionNode> CSSCalcExpressionNodeParser::parseCalc(CSSParserTokenRange tokens, CSSValueID function)
	{
	tokens.consumeWhitespace();

	RefPtr<CSSCalcExpressionNode> result;
	bool ok = parseCalcFunction(tokens, function, 0, result);
	if (!ok \|\| !tokens.atEnd())
	return nullptr;

	if (!result)
	return nullptr;

	LOG_WITH_STREAM(Calc, stream << "CSSCalcExpressionNodeParser::parseCalc " << prettyPrintNode(*result));

	result = CSSCalcOperationNode::simplify(result.releaseNonNull());

	LOG_WITH_STREAM(Calc, stream << "CSSCalcExpressionNodeParser::parseCalc - after simplification " << prettyPrintNode(*result));

	return result;
	}

	char CSSCalcExpressionNodeParser::operatorValue(const CSSParserToken& token)
	{
	if (token.type() == DelimiterToken)
	return token.delimiter();
	return 0;
	}

	enum ParseState {
	OK,
	TooDeep,
	NoMoreTokens
	};

	static const CSSCalcSymbolTable getConstantTable()
	{
	return {
	{ CSSValuePi, CSSUnitType::CSS_NUMBER, piDouble }, { CSSValueE, CSSUnitType::CSS_NUMBER, std::exp(1.0) },
	{ CSSValueNegativeInfinity, CSSUnitType::CSS_NUMBER, -1 * std::numeric_limits<double>::infinity() },
	{ CSSValueInfinity, CSSUnitType::CSS_NUMBER, std::numeric_limits<double>::infinity() },
	{ CSSValueNaN, CSSUnitType::CSS_NUMBER, std::numeric_limits<double>::quiet_NaN() },
	};
	}

	static ParseState checkDepthAndIndex(int depth, CSSParserTokenRange tokens)
	{
	if (tokens.atEnd())
	return NoMoreTokens;
	if (depth > maxExpressionDepth) {
	LOG_WITH_STREAM(Calc, stream << "Depth " << depth << " exceeded maxExpressionDepth " << maxExpressionDepth);
	return TooDeep;
	}
	return OK;
	}

	bool CSSCalcExpressionNodeParser::parseCalcFunction(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
	{
	if (checkDepthAndIndex(depth, tokens) != OK)
	return false;

	// "arguments" refers to things between commas.
	unsigned minArgumentCount = 1;
	std::optional<unsigned> maxArgumentCount;

	switch (functionID) {
	case CSSValueMin:
	case CSSValueMax:
	case CSSValueHypot:
	maxArgumentCount = std::nullopt;
	break;
	case CSSValueClamp:
	minArgumentCount = 3;
	maxArgumentCount = 3;
	break;
	case CSSValueLog:
	maxArgumentCount = 2;
	break;
	case CSSValueRound:
	minArgumentCount = 2;
	maxArgumentCount = 3;
	break;
	case CSSValueMod:
	case CSSValueRem:
	minArgumentCount = 2;
	maxArgumentCount = 2;
	break;
	case CSSValueExp:
	case CSSValueSin:
	case CSSValueCos:
	case CSSValueTan:
	case CSSValueAcos:
	case CSSValueAsin:
	case CSSValueAtan:
	case CSSValueSign:
	case CSSValueAbs:
	case CSSValueCalc:
	maxArgumentCount = 1;
	break;
	case CSSValueAtan2:
	maxArgumentCount = 2;
	break;
	case CSSValuePow:
	minArgumentCount = 2;
	maxArgumentCount = 2;
	break;
	case CSSValueSqrt:
	maxArgumentCount = 1;
	break;
	default:
	break;
	}

	Vector<Ref<CSSCalcExpressionNode>> nodes;

	bool requireComma = false;
	unsigned argumentCount = 0;
	while (!tokens.atEnd()) {
	tokens.consumeWhitespace();
	if (requireComma && !CSSPropertyParserHelpers::consumeCommaIncludingWhitespace(tokens))
	return false;

	RefPtr<CSSCalcExpressionNode> node;
	if (!parseCalcSum(tokens, functionID, depth, node))
	return false;

	++argumentCount;
	if (maxArgumentCount && argumentCount > maxArgumentCount.value())
	return false;

	nodes.append(node.releaseNonNull());
	requireComma = true;
	}

	if (argumentCount < minArgumentCount)
	return false;

	switch (functionID) {
	case CSSValueMin:
	result = CSSCalcOperationNode::createMinOrMaxOrClamp(CalcOperator::Min, WTFMove(nodes), m_destinationCategory);
	break;
	case CSSValueMax:
	result = CSSCalcOperationNode::createMinOrMaxOrClamp(CalcOperator::Max, WTFMove(nodes), m_destinationCategory);
	break;
	case CSSValueClamp:
	result = CSSCalcOperationNode::createMinOrMaxOrClamp(CalcOperator::Clamp, WTFMove(nodes), m_destinationCategory);
	break;
	case CSSValueSin:
	result = CSSCalcOperationNode::createTrig(CalcOperator::Sin, WTFMove(nodes));
	break;
	case CSSValueCos:
	result = CSSCalcOperationNode::createTrig(CalcOperator::Cos, WTFMove(nodes));
	break;
	case CSSValueTan:
	result = CSSCalcOperationNode::createTrig(CalcOperator::Tan, WTFMove(nodes));
	break;
	case CSSValueRound:
	result = CSSCalcOperationNode::createRound(WTFMove(nodes));
	break;
	case CSSValueMod:
	result = CSSCalcOperationNode::createStep(CalcOperator::Mod, WTFMove(nodes));
	break;
	case CSSValueRem:
	result = CSSCalcOperationNode::createStep(CalcOperator::Rem, WTFMove(nodes));
	break;
	case CSSValueWebkitCalc:
	case CSSValueCalc:
	result = CSSCalcOperationNode::createSum(WTFMove(nodes));
	break;
	case CSSValueLog:
	result = CSSCalcOperationNode::createLog(WTFMove(nodes));
	break;
	case CSSValueExp:
	result = CSSCalcOperationNode::createExp(WTFMove(nodes));
	break;
	case CSSValueAcos:
	result = CSSCalcOperationNode::createInverseTrig(CalcOperator::Acos, WTFMove(nodes));
	break;
	case CSSValueAsin:
	result = CSSCalcOperationNode::createInverseTrig(CalcOperator::Asin, WTFMove(nodes));
	break;
	case CSSValueAtan:
	result = CSSCalcOperationNode::createInverseTrig(CalcOperator::Atan, WTFMove(nodes));
	break;
	case CSSValueAtan2:
	result = CSSCalcOperationNode::createAtan2(WTFMove(nodes));
	break;
	case CSSValueAbs:
	result = CSSCalcOperationNode::createSign(CalcOperator::Abs, WTFMove(nodes));
	break;
	case CSSValueSign:
	result = CSSCalcOperationNode::createSign(CalcOperator::Sign, WTFMove(nodes));
	break;
	case CSSValuePow:
	result = CSSCalcOperationNode::createPowOrSqrt(CalcOperator::Pow, WTFMove(nodes));
	break;
	case CSSValueSqrt:
	result = CSSCalcOperationNode::createPowOrSqrt(CalcOperator::Sqrt, WTFMove(nodes));
	break;
	case CSSValueHypot:
	result = CSSCalcOperationNode::createHypot(WTFMove(nodes));
	break;
	default:
	break;
	}

	return !!result;
	}

	static bool checkRoundKeyword(CSSValueID functionID, RefPtr<CSSCalcExpressionNode>& result, CSSValueID constantID)
	{
	if (functionID != CSSValueRound)
	return false;
	switch (constantID) {
	case CSSValueNearest:
	result = CSSCalcOperationNode::createRoundConstant(CalcOperator::Nearest);
	return true;
	case CSSValueToZero:
	result = CSSCalcOperationNode::createRoundConstant(CalcOperator::ToZero);
	return true;
	case CSSValueUp:
	result = CSSCalcOperationNode::createRoundConstant(CalcOperator::Up);
	return true;
	case CSSValueDown:
	result = CSSCalcOperationNode::createRoundConstant(CalcOperator::Down);
	return true;
	default:
	return false;
	}
	}

	bool CSSCalcExpressionNodeParser::parseValue(CSSParserTokenRange& tokens, CSSValueID functionID, RefPtr<CSSCalcExpressionNode>& result)
	{
	auto makeCSSCalcPrimitiveValueNode = [&] (CSSUnitType type, double value) -> bool {
	if (calcUnitCategory(type) == CalculationCategory::Other)
	return false;

	result = CSSCalcPrimitiveValueNode::create(CSSPrimitiveValue::create(value, type));
	return true;
	};

	auto token = tokens.consumeIncludingWhitespace();

	switch (token.type()) {
	case IdentToken: {
	if (checkRoundKeyword(functionID, result, token.id()))
	return true;
	auto value = m_symbolTable.get(token.id());
	value = value ? value : getConstantTable().get(token.id());
	if (!value)
	return false;
	return makeCSSCalcPrimitiveValueNode(value->type, value->value);
	}

	case NumberToken:
	case PercentageToken:
	case DimensionToken:
	return makeCSSCalcPrimitiveValueNode(token.unitType(), token.numericValue());

	default:
	return false;
	}

	ASSERT_NOT_REACHED();
	return false;
	}

	bool CSSCalcExpressionNodeParser::parseCalcValue(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
	{
	if (checkDepthAndIndex(depth, tokens) != OK)
	return false;

	auto findFunctionId = [&](CSSValueID& functionId) {
	if (tokens.peek().type() == LeftParenthesisToken) {
	functionId = CSSValueCalc;
	return true;
	}

	functionId = tokens.peek().functionId();
	return CSSCalcValue::isCalcFunction(functionId);
	};

	CSSValueID functionId;
	if (findFunctionId(functionId)) {
	CSSParserTokenRange innerRange = tokens.consumeBlock();
	tokens.consumeWhitespace();
	innerRange.consumeWhitespace();
	return parseCalcFunction(innerRange, functionId, depth + 1, result);
	}

	return parseValue(tokens, functionID, result);
	}

	bool CSSCalcExpressionNodeParser::parseCalcProduct(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
	{
	if (checkDepthAndIndex(depth, tokens) != OK)
	return false;

	RefPtr<CSSCalcExpressionNode> firstValue;
	if (!parseCalcValue(tokens, functionID, depth, firstValue))
	return false;

	Vector<Ref<CSSCalcExpressionNode>> nodes;

	while (!tokens.atEnd()) {
	char operatorCharacter = operatorValue(tokens.peek());
	if (operatorCharacter != static_cast<char>(CalcOperator::Multiply) && operatorCharacter != static_cast<char>(CalcOperator::Divide))
	break;
	tokens.consumeIncludingWhitespace();

	RefPtr<CSSCalcExpressionNode> nextValue;
	if (!parseCalcValue(tokens, functionID, depth, nextValue) \|\| !nextValue)
	return false;

	if (operatorCharacter == static_cast<char>(CalcOperator::Divide))
	nextValue = CSSCalcInvertNode::create(nextValue.releaseNonNull());

	if (firstValue)
	nodes.append(firstValue.releaseNonNull());

	nodes.append(nextValue.releaseNonNull());
	}

	if (nodes.isEmpty()) {
	result = WTFMove(firstValue);
	return !!result;
	}

	result = CSSCalcOperationNode::createProduct(WTFMove(nodes));
	return !!result;
	}

	bool CSSCalcExpressionNodeParser::parseCalcSum(CSSParserTokenRange& tokens, CSSValueID functionID, int depth, RefPtr<CSSCalcExpressionNode>& result)
	{
	if (checkDepthAndIndex(depth, tokens) != OK)
	return false;

	RefPtr<CSSCalcExpressionNode> firstValue;
	if (!parseCalcProduct(tokens, functionID, depth, firstValue))
	return false;

	Vector<Ref<CSSCalcExpressionNode>> nodes;

	while (!tokens.atEnd()) {
	char operatorCharacter = operatorValue(tokens.peek());
	if (operatorCharacter != static_cast<char>(CalcOperator::Add) && operatorCharacter != static_cast<char>(CalcOperator::Subtract))
	break;

	if ((&tokens.peek() - 1)->type() != WhitespaceToken)
	return false; // calc(1px+ 2px) is invalid

	tokens.consume();
	if (tokens.peek().type() != WhitespaceToken)
	return false; // calc(1px +2px) is invalid

	tokens.consumeIncludingWhitespace();

	RefPtr<CSSCalcExpressionNode> nextValue;
	if (!parseCalcProduct(tokens, functionID, depth, nextValue) \|\| !nextValue)
	return false;

	if (operatorCharacter == static_cast<char>(CalcOperator::Subtract))
	nextValue = CSSCalcNegateNode::create(nextValue.releaseNonNull());

	if (firstValue)
	nodes.append(firstValue.releaseNonNull());

	nodes.append(nextValue.releaseNonNull());
	}

	if (nodes.isEmpty()) {
	result = WTFMove(firstValue);
	return !!result;
	}

	result = CSSCalcOperationNode::createSum(WTFMove(nodes));
	return !!result;
	}

	}