List? _extractReflinkDefinitions()

in lib/src/block_parser.dart [1101:1178]

• 45 lines of code
• 10 McCabe index (conditional complexity)

  List<String>? _extractReflinkDefinitions(
      BlockParser parser, List<String> lines) {
    bool lineStartsReflinkDefinition(int i) =>
        lines[i].startsWith(_reflinkDefinitionStart);

    var i = 0;
    loopOverDefinitions:
    while (true) {
      // Check for reflink definitions.
      if (!lineStartsReflinkDefinition(i)) {
        // It's paragraph content from here on out.
        break;
      }
      var contents = lines[i];
      var j = i + 1;
      while (j < lines.length) {
        // Check to see if the _next_ line might start a new reflink definition.
        // Even if it turns out not to be, but it started with a '[', then it
        // is not a part of _this_ possible reflink definition.
        if (lineStartsReflinkDefinition(j)) {
          // Try to parse [contents] as a reflink definition.
          if (_parseReflinkDefinition(parser, contents)) {
            // Loop again, starting at the next possible reflink definition.
            i = j;
            continue loopOverDefinitions;
          } else {
            // Could not parse [contents] as a reflink definition.
            break;
          }
        } else {
          contents = contents + '\n' + lines[j];
          j++;
        }
      }
      // End of the block.
      if (_parseReflinkDefinition(parser, contents)) {
        i = j;
        break;
      }

      // It may be that there is a reflink definition starting at [i], but it
      // does not extend all the way to [j], such as:
      //
      //     [link]: url     // line i
      //     "title"
      //     garbage
      //     [link2]: url   // line j
      //
      // In this case, [i, i+1] is a reflink definition, and the rest is
      // paragraph content.
      while (j >= i) {
        // This isn't the most efficient loop, what with this big ole'
        // Iterable allocation (`getRange`) followed by a big 'ole String
        // allocation, but we
        // must walk backwards, checking each range.
        contents = lines.getRange(i, j).join('\n');
        if (_parseReflinkDefinition(parser, contents)) {
          // That is the last reflink definition. The rest is paragraph
          // content.
          i = j;
          break;
        }
        j--;
      }
      // The ending was not a reflink definition at all. Just paragraph
      // content.

      break;
    }

    if (i == lines.length) {
      // No paragraph content.
      return null;
    } else {
      // Ends with paragraph content.
      return lines.sublist(i);
    }
  }