learning/tour-of-beam/frontend/lib/cache/content_tree.dart

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import 'dart:async';

import 'package:playground_components/playground_components.dart';

import '../models/content_tree.dart';
import 'cache.dart';

class ContentTreeCache extends Cache {
  ContentTreeCache({
    required super.client,
  });

  final _treesBySdkId = <String, ContentTreeModel>{};
  final _futuresBySdkId = <String, Future<ContentTreeModel>>{};

  ContentTreeModel? getContentTree(Sdk sdk) {
    if (!_futuresBySdkId.containsKey(sdk.id)) {
      unawaited(_loadContentTree(sdk.id));
    }

    return _treesBySdkId[sdk.id];
  }

  Future<ContentTreeModel> _loadContentTree(String sdkId) async {
    final future = client.getContentTree(sdkId);
    _futuresBySdkId[sdkId] = future;

    final result = await future;
    _treesBySdkId[sdkId] = result;

    notifyListeners();
    return result;
  }
}