ImportGraph.build constructor

ImportGraph.build(Map<String, List<String>> directivesByFile, String packageName, { Map<String, String> packages = const {}, })

Builds a graph from directivesByFile, a map of project-relative file path to the raw URIs that file declares.

packageName resolves package:<packageName>/x.dart to lib/x.dart. packages does the same for sub-packages of a monorepo: a directory (packages/core) mapped to the name its own pubspec declares, so package:core/x.dart resolves to packages/core/lib/x.dart.

A URI that does not resolve to a file in directivesByFile is dropped: it points outside the project, or at something that is not there.

Implementation

factory ImportGraph.build(
  Map<String, List<String>> directivesByFile,
  String packageName, {
  Map<String, String> packages = const {},
}) {
  final files = directivesByFile.keys.toSet();
  final edges = <String, Set<String>>{};

  for (final entry in directivesByFile.entries) {
    final from = entry.key;
    final targets = <String>{};
    for (final uri in entry.value) {
      final resolved = resolveUri(
        uri,
        from: from,
        packageName: packageName,
        packages: packages,
      );
      // A self-edge is a file parting or importing itself: not a dependency,
      // and it would show up as a one-file cycle.
      if (resolved != null && resolved != from && files.contains(resolved)) {
        targets.add(resolved);
      }
    }
    edges[from] = targets;
  }
  return ImportGraph(edges, packages: {'': packageName, ...packages});
}