InlineLink? _parseInlineBareDestinationLink()

in lib/src/inline_parser.dart [1223:1294]

• 66 lines of code
• 21 McCabe index (conditional complexity)

  InlineLink? _parseInlineBareDestinationLink(InlineParser parser) {
    // According to
    // [CommonMark](http://spec.commonmark.org/0.28/#link-destination):
    //
    // > A link destination consists of [...] a nonempty sequence of
    // > characters [...], and includes parentheses only if (a) they are
    // > backslash-escaped or (b) they are part of a balanced pair of
    // > unescaped parentheses.
    //
    // We need to count the open parens. We start with 1 for the paren that
    // opened the destination.
    var parenCount = 1;
    var buffer = StringBuffer();

    while (true) {
      var char = parser.charAt(parser.pos);
      switch (char) {
        case $backslash:
          parser.advanceBy(1);
          if (parser.isDone) return null; // EOF. Not a link.
          var next = parser.charAt(parser.pos);
          // Parentheses may be escaped.
          //
          // http://spec.commonmark.org/0.28/#example-467
          if (next != $backslash && next != $lparen && next != $rparen) {
            buffer.writeCharCode(char);
          }
          buffer.writeCharCode(next);
          break;

        case $space:
        case $lf:
        case $cr:
        case $ff:
          var destination = buffer.toString();
          var title = _parseTitle(parser);
          if (title == null &&
              (parser.isDone || parser.charAt(parser.pos) != $rparen)) {
            // This looked like an inline link, until we found this $space
            // followed by mystery characters; no longer a link.
            return null;
          }
          // [_parseTitle] made sure the title was follwed by a closing `)`
          // (but it's up to the code here to examine the balance of
          // parentheses).
          parenCount--;
          if (parenCount == 0) {
            return InlineLink(destination, title: title);
          }
          break;

        case $lparen:
          parenCount++;
          buffer.writeCharCode(char);
          break;

        case $rparen:
          parenCount--;
          if (parenCount == 0) {
            var destination = buffer.toString();
            return InlineLink(destination);
          }
          buffer.writeCharCode(char);
          break;

        default:
          buffer.writeCharCode(char);
      }
      parser.advanceBy(1);
      if (parser.isDone) return null; // EOF. Not a link.
    }
  }