parse static method

List<CSSRule> parse(String sheetText)

Implementation

static List<CSSRule> parse(String sheetText) {
  final List<CSSRule> rules = <CSSRule>[];
  StringBuffer buffer = StringBuffer();
  int state = _BEFORE_SELECTOR;
  for (int pos = 0, length = sheetText.length; pos < length; pos++) {
    int c = sheetText.codeUnitAt(pos);
    switch(c) {
      case DOT_CODE:
        // Current only support single class selector: `.red`.
        int code = sheetText.codeUnitAt(pos + 1);
        // `.` must followed by `-`, `_`, `a-z`, `A-Z`.
        if (state == _BEFORE_SELECTOR && (code == 45 || code == 95 || (code < 123 && code > 96) || (code < 91 && code > 64))) {
          state = _SELECTOR;
          buffer.writeCharCode(c);
        } else if (state != _BEFORE_SELECTOR) {
          buffer.writeCharCode(c);
        }
        break;
      case SPACE_CODE:
      case TAB_CODE:
      case CR_CODE:
      case FEED_CODE:
      case NEWLINE_CODE:
        if (state != _BEFORE_SELECTOR && (state == _SELECTOR || state == _VALUE) && pos > 0) {
          // Squash 2 or more white-spaces in the row into 1 space.
          switch (sheetText.codeUnitAt(pos - 1)) {
            case SPACE_CODE:
            case TAB_CODE:
            case CR_CODE:
            case FEED_CODE:
            case NEWLINE_CODE:
              break;
            default:
              buffer.writeCharCode(SPACE_CODE);
              break;
          }
        }
        break;
      case SEMICOLON_CODE:
        if (state != _BEFORE_SELECTOR && state == _VALUE || state == _NAME) {
          if (state == _NAME) {
            state = _BEFORE_NAME;
          }
          buffer.writeCharCode(c);
        }
        break;
      case OPEN_CURLY_CODE:
        if (state == _SELECTOR) {
          String selector = buffer.toString();
          // Only support single class selector now.
          state = _classSelectorRegExp.hasMatch(selector) ? _BEFORE_NAME : _BEFORE_SELECTOR;
          if (state == _BEFORE_SELECTOR) {
            buffer.clear();
          }
        }
        if (state != _BEFORE_SELECTOR) {
          buffer.writeCharCode(c);
        }
        break;
       case COLON_CODE:
        if (state == _NAME) {
          state = _VALUE;
        }
        if (state != _BEFORE_SELECTOR) {
          buffer.writeCharCode(c);
        }
        break;
      case CLOSE_CURLY_CODE:
        if (state == _BEFORE_SELECTOR) break;
        if (state == _VALUE || state == _BEFORE_NAME) {
          buffer.writeCharCode(c);
          String ruleText = buffer.toString();
          CSSStyleRule? styleRule = CSSStyleRuleParser.parse(ruleText);
          if (styleRule != null) {
            rules.add(styleRule);
          }
        } else if (state == _NAME){
          // `.foo { .x {}; color: red }`
          buffer.writeCharCode(c);
        }

        if (state != _NAME) {
          buffer.clear();
          state = _BEFORE_SELECTOR;
        }
        break;
      default:
        if (state == _BEFORE_SELECTOR) break;
        buffer.writeCharCode(c);
        if (state == _BEFORE_NAME) {
          state = _NAME;
        }
    }
  }
  return rules;
}