static void template()

in lib/src/validate.dart [53:120]
51 lines of code
14 McCabe index (conditional complexity)

  static void template(List<Selector> selectors) {
    var found = false; // signal if a selector is matched.
    var matches = 0; // < 0 IdSelectors, > 0 ClassSelector

    // At most one selector group (any number of simple selector sequences).
    assert(selectors.length <= 1);

    for (final sels in selectors) {
      for (final selector in sels.simpleSelectorSequences) {
        found = false;
        var simpleSelector = selector.simpleSelector;
        if (simpleSelector is ClassSelector) {
          // Any class name starting with an underscore is a private class name
          // that doesn't have to match the world of known classes.
          if (!simpleSelector.name.startsWith('_')) {
            // TODO(terry): For now iterate through all classes look for faster
            //              mechanism hash map, etc.
            for (final className in classes) {
              if (selector.simpleSelector.name == className) {
                matches = _classNameCheck(selector, matches);
                found = true; // .class found.
                break;
              }
              for (final className2 in classes) {
                print(className2);
              }
            }
          } else {
            // Don't check any class name that is prefixed with an underscore.
            // However, signal as found and bump up matches; it's a valid class
            // name.
            matches = _classNameCheck(selector, matches);
            found = true; // ._class are always okay.
          }
        } else if (simpleSelector is IdSelector) {
          // Any element id starting with an underscore is a private element id
          // that doesn't have to match the world of known elemtn ids.
          if (!simpleSelector.name.startsWith('_')) {
            for (final id in ids) {
              if (simpleSelector.name == id) {
                matches = _elementIdCheck(selector, matches);
                found = true; // #id found.
                break;
              }
            }
          } else {
            // Don't check any element ID that is prefixed with an underscore.
            // Signal as found and bump up matches; it's a valid element ID.
            matches = _elementIdCheck(selector, matches);
            found = true; // #_id are always okay
          }
        } else {
          var badSelector = simpleSelector.toString();
          throw CssSelectorException('Invalid template selector $badSelector');
        }

        if (!found) {
          var unknownName = simpleSelector.toString();
          throw CssSelectorException('Unknown selector name $unknownName');
        }
      }
    }

    // Every selector must match.
    var selector = selectors[0];
    assert((matches >= 0 ? matches : -matches) ==
        selector.simpleSelectorSequences.length);
  }