private static TryParseResult TryParseBlock(
string tagName,
Block block,
IEnumerable <TagHelperDescriptor> descriptors,
ErrorSink errorSink,
HashSet <string> processedBoundAttributeNames)
{
// TODO: Accept more than just spans: https://github.com/aspnet/Razor/issues/96.
// The first child will only ever NOT be a Span if a user is doing something like:
// <input @checked />
var childSpan = block.Children.First() as Span;
if (childSpan == null || childSpan.Kind != SpanKindInternal.Markup)
{
errorSink.OnError(
block.Start,
LegacyResources.FormatTagHelpers_CannotHaveCSharpInTagDeclaration(tagName),
block.Length);
return(null);
}
var builder = new BlockBuilder(block);
// If there's only 1 child it means that it's plain text inside of the attribute.
// i.e. <div class="plain text in attribute">
if (builder.Children.Count == 1)
{
return(TryParseSpan(childSpan, descriptors, errorSink, processedBoundAttributeNames));
}
var nameSymbols = childSpan
.Symbols
.OfType <HtmlSymbol>()
.SkipWhile(symbol => !HtmlMarkupParser.IsValidAttributeNameSymbol(symbol)) // Skip prefix
.TakeWhile(nameSymbol => HtmlMarkupParser.IsValidAttributeNameSymbol(nameSymbol))
.Select(nameSymbol => nameSymbol.Content);
var name = string.Concat(nameSymbols);
if (string.IsNullOrEmpty(name))
{
errorSink.OnError(
childSpan.Start,
LegacyResources.FormatTagHelpers_AttributesMustHaveAName(tagName),
childSpan.Length);
return(null);
}
// Have a name now. Able to determine correct isBoundNonStringAttribute value.
var result = CreateTryParseResult(name, descriptors, processedBoundAttributeNames);
var firstChild = builder.Children[0] as Span;
if (firstChild != null && firstChild.Symbols[0] is HtmlSymbol)
{
var htmlSymbol = firstChild.Symbols[firstChild.Symbols.Count - 1] as HtmlSymbol;
switch (htmlSymbol.Type)
{
case HtmlSymbolType.Equals:
if (builder.Children.Count == 2 &&
builder.Children[1] is Span value &&
value.Kind == SpanKindInternal.Markup)
{
// Attribute value is a string literal. Eg: <tag my-attribute=foo />.
result.AttributeStructure = AttributeStructure.NoQuotes;
}
else
{
// Could be an expression, treat NoQuotes and DoubleQuotes equivalently. We purposefully do not persist NoQuotes
// ValueStyles at code generation time to protect users from rendering dynamic content with spaces
// that can break attributes.
// Ex: <tag my-attribute=@value /> where @value results in the test "hello world".
// This way, the above code would render <tag my-attribute="hello world" />.
result.AttributeStructure = AttributeStructure.DoubleQuotes;
}
break;
