/// <summary>
/// Tries to read and set media constraints for the provided medium.
/// </summary>
Boolean TrySetConstraint(CssMedium medium, ref CssToken token)
{
if (token.Type != CssTokenType.Ident)
{
_tokenizer.JumpToClosedArguments();
token = _tokenizer.Get();
return(false);
}
var value = Pool.NewValueBuilder();
var featureName = token.Data;
var val = CssValue.Empty;
var feature = _parser.Options.IsToleratingInvalidConstraints ?
new UnknownMediaFeature(featureName) : Factory.MediaFeatures.Create(featureName);
token = _tokenizer.Get();
if (token.Type == CssTokenType.Colon)
{
_tokenizer.State = CssParseMode.Value;
token = _tokenizer.Get();
while (token.Type != CssTokenType.RoundBracketClose || value.IsReady == false)
{
if (token.Type == CssTokenType.Eof)
{
break;
}
value.Apply(token);
token = _tokenizer.Get();
}
_tokenizer.State = CssParseMode.Data;
val = value.ToPool();
}
else if (token.Type == CssTokenType.Eof)
{
return(false);
}
if (feature != null && feature.TrySetValue(val))
{
medium.AddConstraint(feature);
return(true);
}
return(false);
}
/// <summary>
/// Scans the current medium for the @media or @import rule.
/// </summary>
public CssMedium CreateMedium(ref CssToken token)
{
var medium = new CssMedium();
CollectTrivia(ref token);
if (token.Type == CssTokenType.Ident)
{
var identifier = token.Data;
if (identifier.Isi(Keywords.Not))
{
medium.IsInverse = true;
token = NextToken();
CollectTrivia(ref token);
}
else if (identifier.Isi(Keywords.Only))
{
medium.IsExclusive = true;
token = NextToken();
CollectTrivia(ref token);
}
}
if (token.Type == CssTokenType.Ident)
{
medium.Type = token.Data;
token = NextToken();
CollectTrivia(ref token);
if (token.Type != CssTokenType.Ident || !token.Data.Isi(Keywords.And))
{
return(medium);
}
token = NextToken();
CollectTrivia(ref token);
}
do
{
if (token.Type != CssTokenType.RoundBracketOpen)
{
return(null);
}
token = NextToken();
CollectTrivia(ref token);
CreateNewNode();
var feature = CloseNode(CreateFeature(ref token));
if (feature != null)
{
medium.AddConstraint(feature);
}
if (token.Type != CssTokenType.RoundBracketClose)
{
return(null);
}
token = NextToken();
CollectTrivia(ref token);
if (feature == null)
{
return(null);
}
if (token.Type != CssTokenType.Ident || !token.Data.Isi(Keywords.And))
{
break;
}
token = NextToken();
CollectTrivia(ref token);
}while (token.Type != CssTokenType.Eof);
return(medium);
}