private static bool TryParseSimpleSelector(CssStringStreamReader reader, out CssSimpleSelector selector)
{
selector = null;
reader.SkipWhitespaceAndComments();
switch (reader.CurrentChar)
{
case '#':
reader.Advance();
return
(reader.TryReadIdentifier(out var id) &&
TryParseSimpleSelector(reader, CssSimpleSelectorType.IdSelector, new CssQualifiedName(id), out selector));
case '.':
reader.Advance();
return
(reader.TryReadIdentifier(out var className) &&
TryParseSimpleSelector(reader, CssSimpleSelectorType.ClassSelector, new CssQualifiedName(className), out selector));
case '*':
reader.Advance();
return(TryParseUniversalSelector(reader, out selector));
case '[':
case ':':
return(TryParseUniversalSelector(reader, out selector));
default:
return
(reader.TryReadQualifiedName(out var typeName) &&
TryParseSimpleSelector(reader, CssSimpleSelectorType.TypeSelector, typeName, out selector));
}
}
private static bool TryParseCompoundSelector(CssStringStreamReader reader, out CssCompoundSelector selector)
{
var simpleSelectors = new List <CssSimpleSelector>();
reader.SkipWhitespaceAndComments();
while (!reader.IsEndOfStream)
{
if (!TryParseSimpleSelector(reader, out var simpleSelector))
{
break;
}
simpleSelectors.Add(simpleSelector);
if (IsCombinatorChar(reader.CurrentChar))
{
break;
}
}
if (simpleSelectors.Count == 0)
{
selector = null;
return(false);
}
selector = new CssCompoundSelector(simpleSelectors.ToArray());
return(true);
}
private static bool TryParseSimpleSelector(CssStringStreamReader reader, CssSimpleSelectorType simpleSelectorType, CssQualifiedName name, out CssSimpleSelector selector)
{
var attributeSelectors = ParseAttributeSelectors(reader);
var pseudoClasses = ParsePseudoClasses(reader);
if (attributeSelectors == null || pseudoClasses == null)
{
selector = null;
return(false);
}
selector = new CssSimpleSelector(simpleSelectorType, name, attributeSelectors, pseudoClasses);
return(true);
}
private static CssPseudoClass[] ParsePseudoClasses(CssStringStreamReader reader)
{
var classes = new List <CssPseudoClass>();
while (reader.CurrentChar == ':')
{
reader.Advance();
if (!reader.TryReadIdentifier(out var className))
{
return(null);
}
if (CssFunctionalPseudoClass.TryConvertToFunctionalPseudoClassType(className, out var functionalClassType))
{
if (!reader.Read('(') ||
!TryParseSelectorList(reader, out var functionalSelectors) ||
!reader.Read(')'))
{
return(null);
}
classes.Add(new CssFunctionalPseudoClass(functionalSelectors, functionalClassType));
continue;
}
if (CssUserActionPseudoClass.TryConvertToUserActionPseudoClassType(className, out var userActionClassType))
{
classes.Add(new CssUserActionPseudoClass(userActionClassType));
continue;
}
if (CssStructuralPseudoClass.TryConvertToStructuralPseudoClassType(className, out var structuralPseudoClassType))
{
if (!reader.Read('(') ||
!TryParseSelectorList(reader, out var structuralSelectors) ||
!reader.Read(')'))
{
structuralSelectors = new CssSelectorList();
}
classes.Add(new CssStructuralPseudoClass(structuralSelectors, structuralPseudoClassType));
continue;
}
return(null); // unknown / unhandled pseudo class
}
return(classes.ToArray());
}
public static bool TryParseSelectorList(CssStringStreamReader reader, out CssSelectorList selectors)
{
selectors = new CssSelectorList();
while (!reader.IsEndOfStream)
{
if (!TryParseComplexSelector(reader, out var complex))
{
break;
}
selectors.Add(Flatten(complex));
reader.SkipWhitespaceAndComments();
if (reader.CurrentChar != ',')
{
break;
}
reader.Advance();
}
return(selectors.Count > 0);
}
private static CssAttributeSelector[] ParseAttributeSelectors(CssStringStreamReader reader)
{
var selectors = new List <CssAttributeSelector>();
while (reader.CurrentChar == '[')
{
reader.Advance();
if (!reader.TryReadIdentifier(out var name) || !reader.TryReadCssAttributeSelectorOperation(out var op))
{
return(null);
}
var value = string.Empty;
var wasString = false;
if (op != CssAttributeSelectorOperation.Has)
{
if (!reader.TryReadIdentifierOrString(out value, out wasString))
{
return(null);
}
}
reader.SkipWhitespaceAndComments();
var explicitIgnoreCase = reader.CurrentChar == 'i';
if (explicitIgnoreCase)
{
reader.Advance();
reader.SkipWhitespaceAndComments();
}
if (reader.CurrentChar != ']')
{
return(null);
}
reader.Advance();
var valueType = wasString ? CssAttributeSelectorValueType.String : CssAttributeSelectorValueType.Identifier;
selectors.Add(new CssAttributeSelector(name, value, op, valueType, explicitIgnoreCase));
}
return(selectors.ToArray());
}
/// <summary>
/// Tries to parse a collection of properties (name value pairs, e.g. 'fill:#000') of a style body
/// </summary>
public static bool TryParseStyleRuleBodyProperties(CssStringStreamReader reader, out Dictionary <string, CssStylePropertyValue> properties)
{
properties = new Dictionary <string, CssStylePropertyValue>();
reader.SkipWhitespaceAndComments();
var builder = new StringBuilder();
while (!reader.IsEndOfStream && reader.CurrentChar != '}')
{
if (!reader.TryReadIdentifier(out var name))
{
return(false);
}
reader.SkipWhitespaceAndComments();
if (!reader.Read(':'))
{
return(false);
}
reader.SkipWhitespaceAndComments();
while (reader.CurrentChar != ';' && reader.CurrentChar != '}' && !reader.IsEndOfStream)
{
builder.Append(reader.CurrentChar);
reader.Advance();
}
properties[name] = new CssStylePropertyValue(builder.ToString());
builder.Clear();
if (reader.CurrentChar == ';')
{
reader.Read(';');
}
reader.SkipWhitespaceAndComments();
}
return(true);
}
public static bool TryParseRules(CssStringStreamReader reader, out CssStyleRulesList rules)
{
rules = new CssStyleRulesList();
reader.SkipWhitespaceAndComments();
while (!reader.IsEndOfStream)
{
if (!TryParseSelectorList(reader, out var selectors) ||
!reader.SkipWhitespaceAndComments() ||
!reader.Read('{') ||
!TryParseStyleRuleBodyProperties(reader, out var properties) ||
!reader.SkipWhitespaceAndComments() ||
!reader.Read('}'))
{
return(false);
}
rules.Add(new CssStyleRule(selectors, properties));
reader.SkipWhitespaceAndComments();
}
return(true);
}
private static bool TryParseComplexSelector(CssStringStreamReader reader, out CssComplexSelector selector)
{
var items = new List <CssComplexSelectorItem>();
while (!reader.IsEndOfStream)
{
if (!TryParseCompoundSelector(reader, out var compound))
{
if (items.Count > 0)
{
var last = items[items.Count - 1];
if (last.Combinator == CssCombinatorType.Descendant)
{
// remove the last items combinator
items[items.Count - 1] = new CssComplexSelectorItem(last.Selector, null);
}
else
{
items.Clear();
}
}
break;
}
var hasCombinator = reader.TryReadCombinatorType(out var combinator);
items.Add(hasCombinator
? new CssComplexSelectorItem(compound, combinator)
: new CssComplexSelectorItem(compound, null));
if (!hasCombinator)
{
break;
}
}
selector = items.Count > 0 ? new CssComplexSelector(items.ToArray()) : null;
return(selector != null);
}
private static bool TryParseUniversalSelector(CssStringStreamReader reader, out CssSimpleSelector selector)
=> TryParseSimpleSelector(reader, CssSimpleSelectorType.UniversalSelector, new CssQualifiedName("*"), out selector);
internal CssParserException(CssStringStreamReader reader, string message)
: base($"'{reader.Stream.Substring(Math.Max(0, reader.Position - 10))}', {message}")
{
}
){kind=link}
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