/// <summary>
/// Retrieves unquoted attribute value
/// </summary>
/// <returns>Attribute value token</returns>
public IHtmlAttributeValueToken GetUnquotedAttributeValue(int tagEnd)
{
// Need to handle <a b=c=d /> and figure out that c=d is a valid pair while
// b= is missing a value. One way is to check if 'c' happens to be
// one of the known HTML attributes, but it only works for plain HTML
// and won't work for ASP.NET controls that can define any attributes
// via .NET properties.
// Options (value is unquoted)
// a. Attribute value is either a sequence of characters or a number
// except if it is ID or CLASS.
// b. Attribute name is typically a sequence of characters and does not include digits
// c. Attribute value is not normally followed by =
Debug.Assert(!_cs.IsAtString());
AttributeValueToken token = null;
int start = _cs.Position;
int end = _cs.Position;
ITextRange nextTokenRange;
NextTokenType nextTokenType = NextToken.PeekNextToken(_cs, tagEnd, out nextTokenRange);
switch (nextTokenType)
{
case NextTokenType.None: // attrName={EOF}
case NextTokenType.Tag: // attName=<foo
case NextTokenType.Equals: // attrName==
return(null);
case NextTokenType.Number:
// attrName = 1.0
case NextTokenType.Unknown:
// id=#
case NextTokenType.Identifier:
// attrName = foo12. There are no know attributes of this form.
end = nextTokenRange.End;
break;
case NextTokenType.Letters:
// Legal value. Need to check against attribute names to be sure.
bool isKnownAttribute = AttributeTable.IsKnownAttribute(_cs.GetSubstringAt(nextTokenRange.Start, nextTokenRange.Length));
if (!isKnownAttribute)
{
end = nextTokenRange.End;
}
break;
}
char closeQuote = '\0';
if (end > start)
{
closeQuote = _cs[end - 1];
if (closeQuote != '\'' && closeQuote != '\"')
{
closeQuote = '\0';
}
}
token = AttributeValueToken.Create(HtmlToken.FromBounds(start, end), '\0', closeQuote);
_cs.Position = end;
return(token);
}
public static NextTokenType PeekNextToken(HtmlCharStream cs, int tagEnd, out ITextRange range)
{
NextTokenType tokenType = NextTokenType.Unknown;
int current = cs.Position;
if (cs.IsEndOfStream() || cs.Position == tagEnd)
{
range = new TextRange();
return(NextTokenType.None);
}
int start = cs.Position;
while (cs.IsWhiteSpace())
{
cs.MoveToNextChar();
}
if (cs.IsEndOfStream() || cs.Position == tagEnd)
{
range = TextRange.FromBounds(start, cs.Position);
return(NextTokenType.Unknown);
}
if (cs.IsAtTagDelimiter())
{
tokenType = NextTokenType.Tag;
}
else if (cs.CurrentChar == '=')
{
tokenType = NextTokenType.Equals;
}
else
{
int digits = 0;
bool firstLetter = false;
int length = 0;
int chars = 0;
if (cs.IsAnsiLetter())
{
firstLetter = true;
}
while (!cs.IsEndOfStream() && !cs.IsWhiteSpace() && !cs.IsAtTagDelimiter() && cs.CurrentChar != '=' && cs.Position < tagEnd)
{
if (cs.IsAnsiLetter() || cs.CurrentChar == '_' || cs.CurrentChar == '-')
{
chars++;
}
else if (cs.IsDecimal() || cs.CurrentChar == '.')
{
digits++;
}
cs.MoveToNextChar();
length++;
}
if (length > 0)
{
if (length == digits)
{
tokenType = NextTokenType.Number;
}
else if (length == chars)
{
tokenType = NextTokenType.Letters;
}
else if (firstLetter)
{
tokenType = NextTokenType.Identifier;
}
}
}
range = TextRange.FromBounds(start, cs.Position);
cs.Position = current;
return(tokenType);
}
