ui/src/controller/app_controller.ts

// Copyright (C) 2018 The Android Open Source Project
//
// Licensed 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 {RECORDING_V2_FLAG} from '../core/feature_flags';
import {globals} from '../frontend/globals';

import {Child, Controller, ControllerInitializerAny} from './controller';
import {RecordController} from './record_controller';
import {TraceController} from './trace_controller';

// The root controller for the entire app. It handles the lifetime of all
// the other controllers (e.g., track and query controllers) according to the
// global state.
export class AppController extends Controller<'main'> {
  // extensionPort is needed for the RecordController to communicate with the
  // extension through the frontend. This is because the controller is running
  // on a worker, and isn't able to directly send messages to the extension.
  private extensionPort: MessagePort;

  constructor(extensionPort: MessagePort) {
    super('main');
    this.extensionPort = extensionPort;
  }

  // This is the root method that is called every time the controller tree is
  // re-triggered. This can happen due to:
  // - An action received from the frontend.
  // - An internal promise of a nested controller being resolved and manually
  //   re-triggering the controllers.
  run() {
    const childControllers: ControllerInitializerAny[] = [];
    if (!RECORDING_V2_FLAG.get()) {
      childControllers.push(
        Child('record', RecordController, {extensionPort: this.extensionPort}),
      );
    }
    if (globals.state.engine !== undefined) {
      const engineCfg = globals.state.engine;
      childControllers.push(Child(engineCfg.id, TraceController, engineCfg.id));
    }
    return childControllers;
  }
}