PackageConfig parse()

in lib/src/packages_file.dart [33:141]
108 lines of code
28 McCabe index (conditional complexity)

PackageConfig parse(
    List<int> source, Uri baseLocation, void Function(Object error) onError) {
  if (baseLocation.isScheme('package')) {
    onError(PackageConfigArgumentError(
        baseLocation, 'baseLocation', 'Must not be a package: URI'));
    return PackageConfig.empty;
  }
  var index = 0;
  var packages = <Package>[];
  var packageNames = <String>{};
  while (index < source.length) {
    var ignoreLine = false;
    var start = index;
    var separatorIndex = -1;
    var end = source.length;
    var char = source[index++];
    if (char == $cr || char == $lf) {
      continue;
    }
    if (char == $colon) {
      onError(PackageConfigFormatException(
          'Missing package name', source, index - 1));
      ignoreLine = true; // Ignore if package name is invalid.
    } else {
      ignoreLine = char == $hash; // Ignore if comment.
    }
    var queryStart = -1;
    var fragmentStart = -1;
    while (index < source.length) {
      char = source[index++];
      if (char == $colon && separatorIndex < 0) {
        separatorIndex = index - 1;
      } else if (char == $cr || char == $lf) {
        end = index - 1;
        break;
      } else if (char == $question && queryStart < 0 && fragmentStart < 0) {
        queryStart = index - 1;
      } else if (char == $hash && fragmentStart < 0) {
        fragmentStart = index - 1;
      }
    }
    if (ignoreLine) continue;
    if (separatorIndex < 0) {
      onError(
          PackageConfigFormatException("No ':' on line", source, index - 1));
      continue;
    }
    var packageName = String.fromCharCodes(source, start, separatorIndex);
    var invalidIndex = checkPackageName(packageName);
    if (invalidIndex >= 0) {
      onError(PackageConfigFormatException(
          'Not a valid package name', source, start + invalidIndex));
      continue;
    }
    if (queryStart >= 0) {
      onError(PackageConfigFormatException(
          'Location URI must not have query', source, queryStart));
      end = queryStart;
    } else if (fragmentStart >= 0) {
      onError(PackageConfigFormatException(
          'Location URI must not have fragment', source, fragmentStart));
      end = fragmentStart;
    }
    var packageValue = String.fromCharCodes(source, separatorIndex + 1, end);
    Uri packageLocation;
    try {
      packageLocation = Uri.parse(packageValue);
    } on FormatException catch (e) {
      onError(PackageConfigFormatException.from(e));
      continue;
    }
    var relativeRoot = !hasAbsolutePath(packageLocation);
    packageLocation = baseLocation.resolveUri(packageLocation);
    if (packageLocation.isScheme('package')) {
      onError(PackageConfigFormatException(
          'Package URI as location for package', source, separatorIndex + 1));
      continue;
    }
    var path = packageLocation.path;
    if (!path.endsWith('/')) {
      path += '/';
      packageLocation = packageLocation.replace(path: path);
    }
    if (packageNames.contains(packageName)) {
      onError(PackageConfigFormatException(
          'Same package name occured more than once', source, start));
      continue;
    }
    var rootUri = packageLocation;
    if (path.endsWith('/lib/')) {
      // Assume default Pub package layout. Include package itself in root.
      rootUri =
          packageLocation.replace(path: path.substring(0, path.length - 4));
    }
    var package = SimplePackage.validate(packageName, rootUri, packageLocation,
        _languageVersion, null, relativeRoot, (error) {
      if (error is ArgumentError) {
        onError(PackageConfigFormatException(error.message, source));
      } else {
        onError(error);
      }
    });
    if (package != null) {
      packages.add(package);
      packageNames.add(packageName);
    }
  }
  return SimplePackageConfig(1, packages, null, onError);
}