matchedRules method

Implementation

List<CSSRule> matchedRules(RuleSet ruleSet, Element element) {
  List<CSSRule> matchedRules = [];

  int candidateCount = 0;
  // Reuse a single evaluator per matchedRules() to avoid repeated allocations.
  final SelectorEvaluator evaluator = SelectorEvaluator();
  // Build ancestor token sets once per call if fast-path is enabled, to avoid
  // repeatedly walking the ancestor chain for each candidate rule.
  final _AncestorTokenSet? ancestorTokens = DebugFlags.enableCssAncestryFastPath
      ? _buildAncestorTokens(element)
      : null;

  if (ruleSet.isEmpty) {
    return matchedRules;
  }

  // #id
  String? id = element.id;
  if (id != null) {
    final list = ruleSet.idRules[id];
    candidateCount += (list?.length ?? 0);
    matchedRules.addAll(_collectMatchingRulesForList(
      list,
      element,
      evaluator: evaluator,
      enableAncestryFastPath: DebugFlags.enableCssAncestryFastPath,
      ancestorTokens: ancestorTokens,
    ));
  }

  // .class
  for (String className in element.classList) {
    final list = ruleSet.classRules[className];
    candidateCount += (list?.length ?? 0);
    matchedRules.addAll(_collectMatchingRulesForList(
      list,
      element,
      evaluator: evaluator,
      enableAncestryFastPath: DebugFlags.enableCssAncestryFastPath,
      ancestorTokens: ancestorTokens,
    ));
  }

  // attribute selector
  for (String attribute in element.attributes.keys) {
    final list = ruleSet.attributeRules[attribute.toUpperCase()];
    candidateCount += (list?.length ?? 0);
    matchedRules.addAll(_collectMatchingRulesForList(
      list,
      element,
      evaluator: evaluator,
      enableAncestryFastPath: DebugFlags.enableCssAncestryFastPath,
      ancestorTokens: ancestorTokens,
    ));
  }

  // tag selectors are stored uppercase; normalize element tag for lookup.
  final String tagLookup = element.tagName.toUpperCase();
  final listTag = ruleSet.tagRules[tagLookup];
  candidateCount += (listTag?.length ?? 0);
  matchedRules.addAll(_collectMatchingRulesForList(
    listTag,
    element,
    evaluator: evaluator,
    enableAncestryFastPath: DebugFlags.enableCssAncestryFastPath,
    ancestorTokens: ancestorTokens,
  ));

  // universal
  candidateCount += ruleSet.universalRules.length;
  matchedRules.addAll(_collectMatchingRulesForList(
    ruleSet.universalRules,
    element,
    evaluator: evaluator,
    enableAncestryFastPath: DebugFlags.enableCssAncestryFastPath,
    ancestorTokens: ancestorTokens,
  ));



  return matchedRules;
}