protobuf/lib/src/protobuf/type_registry.dart

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import '../../protobuf.dart';

/// A TypeRegistry is used to resolve Any messages in the proto3 JSON conversion.
///
/// You must provide a TypeRegistry containing all message types used in
/// Any message fields, or the JSON conversion will fail because data
/// in Any message fields is unrecognizable. You don't need to supply a
/// TypeRegistry if you don't use Any message fields.
class TypeRegistry {
  final Map<String, BuilderInfo> _mapping;

  /// Constructs a new TypeRegistry recognizing the given types of messages.
  ///
  /// You can use an empty message of the given type to represent the type. Eg:
  ///
  /// ```dart
  /// TypeRegistry([Foo(), Bar()]);
  /// ```
  TypeRegistry(Iterable<GeneratedMessage> types)
      : _mapping = Map.fromEntries(types.map((message) =>
            MapEntry(message.info_.qualifiedMessageName, message.info_)));

  const TypeRegistry.empty() : _mapping = const {};

  BuilderInfo lookup(String qualifiedName) {
    return _mapping[qualifiedName];
  }
}