resolvePackageDirectory function

Future<String> resolvePackageDirectory(String packageUri)

Resolves the root directory path of a package given a packageUri string (e.g. 'package:undead/undead.dart').

Traverses up from the resolved lib/ directory to locate the package root.

Implementation

Future<String> resolvePackageDirectory(String packageUri) async {
  final uri = Uri.parse(packageUri);
  if (!uri.isScheme('package') || uri.pathSegments.isEmpty) {
    throw ArgumentError.value(
      packageUri,
      'packageUri',
      'Must be a valid package: URI (e.g. "package:pkg/pkg.dart").',
    );
  }

  final resolved = await Isolate.resolvePackageUri(uri);
  if (resolved == null) {
    throw StateError(
      'Could not resolve package URI: "$packageUri". '
      'Ensure the package is declared in dependencies or dev_dependencies.',
    );
  }

  var currentDir = p.dirname(resolved.toFilePath());
  // The path inside lib/ has (uri.pathSegments.length - 1) segments.
  // Climbing up (uri.pathSegments.length - 1) times from the file's parent
  // directory reaches the package root across all platform path separators.
  for (var i = 1; i < uri.pathSegments.length; i++) {
    currentDir = p.dirname(currentDir);
  }
  return p.normalize(currentDir);
}