String checkValidPackageUri()

in lib/src/util.dart [49:101]
47 lines of code
12 McCabe index (conditional complexity)

String checkValidPackageUri(Uri packageUri, String name) {
  if (packageUri.scheme != 'package') {
    throw PackageConfigArgumentError(packageUri, name, 'Not a package: URI');
  }
  if (packageUri.hasAuthority) {
    throw PackageConfigArgumentError(
        packageUri, name, 'Package URIs must not have a host part');
  }
  if (packageUri.hasQuery) {
    // A query makes no sense if resolved to a file: URI.
    throw PackageConfigArgumentError(
        packageUri, name, 'Package URIs must not have a query part');
  }
  if (packageUri.hasFragment) {
    // We could leave the fragment after the URL when resolving,
    // but it would be odd if "package:foo/foo.dart#1" and
    // "package:foo/foo.dart#2" were considered different libraries.
    // Keep the syntax open in case we ever get multiple libraries in one file.
    throw PackageConfigArgumentError(
        packageUri, name, 'Package URIs must not have a fragment part');
  }
  if (packageUri.path.startsWith('/')) {
    throw PackageConfigArgumentError(
        packageUri, name, "Package URIs must not start with a '/'");
  }
  var firstSlash = packageUri.path.indexOf('/');
  if (firstSlash == -1) {
    throw PackageConfigArgumentError(packageUri, name,
        "Package URIs must start with the package name followed by a '/'");
  }
  var packageName = packageUri.path.substring(0, firstSlash);
  var badIndex = checkPackageName(packageName);
  if (badIndex >= 0) {
    if (packageName.isEmpty) {
      throw PackageConfigArgumentError(
          packageUri, name, 'Package names mus be non-empty');
    }
    if (badIndex == packageName.length) {
      throw PackageConfigArgumentError(packageUri, name,
          "Package names must contain at least one non-'.' character");
    }
    assert(badIndex < packageName.length);
    var badCharCode = packageName.codeUnitAt(badIndex);
    var badChar = 'U+' + badCharCode.toRadixString(16).padLeft(4, '0');
    if (badCharCode >= 0x20 && badCharCode <= 0x7e) {
      // Printable character.
      badChar = "'${packageName[badIndex]}' ($badChar)";
    }
    throw PackageConfigArgumentError(
        packageUri, name, 'Package names must not contain $badChar');
  }
  return packageName;
}