String IntersectionObserver::rootMargin() const
{
StringBuilder stringBuilder;
appendLength(stringBuilder, m_topMargin);
stringBuilder.append(' ');
appendLength(stringBuilder, m_rightMargin);
stringBuilder.append(' ');
appendLength(stringBuilder, m_bottomMargin);
stringBuilder.append(' ');
appendLength(stringBuilder, m_leftMargin);
return stringBuilder.toString();
}
bool SizesCalcParser::calcToReversePolishNotation(CSSParserTokenIterator start, CSSParserTokenIterator end)
{
// This method implements the shunting yard algorithm, to turn the calc syntax into a reverse polish notation.
// http://en.wikipedia.org/wiki/Shunting-yard_algorithm
Vector<CSSParserToken> stack;
for (CSSParserTokenIterator it = start; it != end; ++it) {
CSSParserTokenType type = it->type();
switch (type) {
case NumberToken:
appendNumber(*it);
break;
case DimensionToken:
if (!CSSPrimitiveValue::isLength(it->unitType()) || !appendLength(*it))
return false;
break;
case DelimiterToken:
if (!handleOperator(stack, *it))
return false;
break;
case FunctionToken:
if (it->value() != "calc")
return false;
// "calc(" is the same as "("
case LeftParenthesisToken:
// If the token is a left parenthesis, then push it onto the stack.
stack.append(*it);
break;
case RightParenthesisToken:
// If the token is a right parenthesis:
// Until the token at the top of the stack is a left parenthesis, pop operators off the stack onto the output queue.
while (!stack.isEmpty() && stack.last().type() != LeftParenthesisToken && stack.last().type() != FunctionToken) {
appendOperator(stack.last());
stack.removeLast();
}
// If the stack runs out without finding a left parenthesis, then there are mismatched parentheses.
if (stack.isEmpty())
return false;
// Pop the left parenthesis from the stack, but not onto the output queue.
stack.removeLast();
break;
case CommentToken:
case WhitespaceToken:
case EOFToken:
break;
case HashToken:
case UrlToken:
case BadUrlToken:
case PercentageToken:
case UnicodeRangeToken:
case IdentToken:
case CommaToken:
case ColonToken:
case SemicolonToken:
case LeftBraceToken:
case LeftBracketToken:
case RightBraceToken:
case RightBracketToken:
case StringToken:
case BadStringToken:
return false;
}
}
// When there are no more tokens to read:
// While there are still operator tokens in the stack:
while (!stack.isEmpty()) {
// If the operator token on the top of the stack is a parenthesis, then there are mismatched parentheses.
CSSParserTokenType type = stack.last().type();
if (type == LeftParenthesisToken || type == FunctionToken)
return false;
// Pop the operator onto the output queue.
appendOperator(stack.last());
stack.removeLast();
}
return true;
}
bool SizesCalcParser::calcToReversePolishNotation(CSSParserTokenRange range)
{
// This method implements the shunting yard algorithm, to turn the calc syntax into a reverse polish notation.
// http://en.wikipedia.org/wiki/Shunting-yard_algorithm
Vector<CSSParserToken> stack;
while (!range.atEnd()) {
const CSSParserToken& token = range.consume();
switch (token.type()) {
case NumberToken:
appendNumber(token);
break;
case DimensionToken:
if (!CSSPrimitiveValue::isLength(token.unitType()) || !appendLength(token))
return false;
break;
case DelimiterToken:
if (!handleOperator(stack, token))
return false;
break;
case FunctionToken:
if (!token.valueEqualsIgnoringCase("calc"))
return false;
// "calc(" is the same as "("
case LeftParenthesisToken:
// If the token is a left parenthesis, then push it onto the stack.
stack.append(token);
break;
case RightParenthesisToken:
// If the token is a right parenthesis:
// Until the token at the top of the stack is a left parenthesis, pop operators off the stack onto the output queue.
while (!stack.isEmpty() && stack.last().type() != LeftParenthesisToken && stack.last().type() != FunctionToken) {
appendOperator(stack.last());
stack.removeLast();
}
// If the stack runs out without finding a left parenthesis, then there are mismatched parentheses.
if (stack.isEmpty())
return false;
// Pop the left parenthesis from the stack, but not onto the output queue.
stack.removeLast();
break;
case WhitespaceToken:
case EOFToken:
break;
case CommentToken:
ASSERT_NOT_REACHED();
case CDOToken:
case CDCToken:
case AtKeywordToken:
case HashToken:
case UrlToken:
case BadUrlToken:
case PercentageToken:
case IncludeMatchToken:
case DashMatchToken:
case PrefixMatchToken:
case SuffixMatchToken:
case SubstringMatchToken:
case ColumnToken:
case UnicodeRangeToken:
case IdentToken:
case CommaToken:
case ColonToken:
case SemicolonToken:
case LeftBraceToken:
case LeftBracketToken:
case RightBraceToken:
case RightBracketToken:
case StringToken:
case BadStringToken:
return false;
}
}
// When there are no more tokens to read:
// While there are still operator tokens in the stack:
while (!stack.isEmpty()) {
// If the operator token on the top of the stack is a parenthesis, then there are mismatched parentheses.
CSSParserTokenType type = stack.last().type();
if (type == LeftParenthesisToken || type == FunctionToken)
return false;
// Pop the operator onto the output queue.
appendOperator(stack.last());
stack.removeLast();
}
return true;
}