decodeXrayJson function

Object? decodeXrayJson(String input)

Decode one Xray document (or subscription array) with Core-style comments.

Xray's local-file reader removes //, /* */ and # comments outside strings. Newlines in comments are retained, including within numeric tokens. Unlike its streaming decoder, this API rejects trailing documents/data explicitly; they must not silently disappear. One leading UTF-8 BOM is a portable import extension; native Core always receives ordinary JSON after normalization.

Throws FormatException for malformed JSON, unsupported JSON5 forms, or trailing data. No network, file or native configuration validation is run.

Implementation

Object? decodeXrayJson(String input) {
  final source = input.startsWith('\uFEFF') ? input.substring(1) : input;
  final output = StringBuffer();
  var quote = 0;
  var escaped = false;
  var lineComment = false;
  var blockComment = false;
  var blockStar = false;
  for (var i = 0; i < source.length; i++) {
    final char = source.codeUnitAt(i);
    final next = i + 1 < source.length ? source.codeUnitAt(i + 1) : -1;
    if (lineComment) {
      if (char == 10) {
        lineComment = false;
        output.writeCharCode(char);
      }
      continue;
    }
    if (blockComment) {
      if (blockStar) {
        if (char == 47) {
          blockComment = false;
          blockStar = false;
        } else if (char == 10) {
          // Core retains the star state across LF, including *\n/.
          output.writeCharCode(char);
        } else if (char != 42) {
          blockStar = false;
        }
      } else if (char == 42) {
        blockStar = true;
      } else if (char == 10) {
        output.writeCharCode(char);
      }
      continue;
    }
    if (quote != 0) {
      output.writeCharCode(char);
      if (escaped) {
        escaped = false;
      } else if (char == 92) {
        escaped = true;
      } else if (char == quote) {
        quote = 0;
      }
      continue;
    }
    if (char == 34 || char == 39) {
      // Single quotes stay intact; the JSON decoder rejects JSON5 syntax.
      quote = char;
    } else if (char == 35 || (char == 47 && next == 47)) {
      lineComment = true;
      if (char == 47) i++;
      continue;
    } else if (char == 47 && next == 42) {
      blockComment = true;
      i++;
      continue;
    }
    output.writeCharCode(char);
  }
  return jsonDecode(output.toString());
}