xit('works', done => {
    const workflow = new NodeWorkflow(new NodeJsSyncHost(), { dryRun: true });
    const collection = path.join(__dirname, '../../../../schematics/angular/package.json');

    workflow.execute({
      collection,
      schematic: 'ng-new',
      options: { name: 'workflow-test', version: '6.0.0-rc.4' },
    }).toPromise().then(done, done.fail);
  });

export async function main({
  args,
  stdout = process.stdout,
  stderr = process.stderr,
}: MainOptions): Promise<0 | 1> {

  const argv = parseArgs(args);

  /** Create the DevKit Logger used through the CLI. */
  const logger = createConsoleLogger(argv['verbose'], stdout, stderr);
  if (argv.help) {
    logger.info(getUsage());

    return 0;
  }

  /** Get the collection an schematic name from the first argument. */
  const {
    collection: collectionName,
    schematic: schematicName,
  } = parseSchematicName(argv._.shift() || null);
  const isLocalCollection = collectionName.startsWith('.') || collectionName.startsWith('/');

  /** If the user wants to list schematics, we simply show all the schematic names. */
  if (argv['list-schematics']) {
    try {
      const engineHost = new NodeModulesEngineHost();
      const engine = new SchematicEngine(engineHost);
      const collection = engine.createCollection(collectionName);
      logger.info(engine.listSchematicNames(collection).join('\n'));
    } catch (error) {
      logger.fatal(error.message);

      return 1;
    }

    return 0;
  }

  if (!schematicName) {
    logger.info(getUsage());

    return 1;
  }

  /** Gather the arguments for later use. */
  const debug: boolean = argv.debug === null ? isLocalCollection : argv.debug;
  const dryRun: boolean = argv['dry-run'] === null ? debug : argv['dry-run'];
  const force = argv['force'];
  const allowPrivate = argv['allow-private'];

  /** Create a Virtual FS Host scoped to where the process is being run. **/
  const fsHost = new virtualFs.ScopedHost(new NodeJsSyncHost(), normalize(process.cwd()));

  /** Create the workflow that will be executed with this run. */
  const workflow = new NodeWorkflow(fsHost, { force, dryRun });

  // Indicate to the user when nothing has been done. This is automatically set to off when there's
  // a new DryRunEvent.
  let nothingDone = true;

  // Logging queue that receives all the messages to show the users. This only get shown when no
  // errors happened.
  let loggingQueue: string[] = [];
  let error = false;

  /**
   * Logs out dry run events.
   *
   * All events will always be executed here, in order of discovery. That means that an error would
   * be shown along other events when it happens. Since errors in workflows will stop the Observable
   * from completing successfully, we record any events other than errors, then on completion we
   * show them.
   *
   * This is a simple way to only show errors when an error occur.
   */
  workflow.reporter.subscribe((event: DryRunEvent) => {
    nothingDone = false;

    switch (event.kind) {
      case 'error':
        error = true;

        const desc = event.description == 'alreadyExist' ? 'already exists' : 'does not exist';
        logger.warn(`ERROR! ${event.path} ${desc}.`);
        break;
      case 'update':
        loggingQueue.push(tags.oneLine`
        ${terminal.white('UPDATE')} ${event.path} (${event.content.length} bytes)
      `);
        break;
      case 'create':
        loggingQueue.push(tags.oneLine`
        ${terminal.green('CREATE')} ${event.path} (${event.content.length} bytes)
      `);
        break;
      case 'delete':
        loggingQueue.push(`${terminal.yellow('DELETE')} ${event.path}`);
        break;
      case 'rename':
//.........这里部分代码省略.........

  process.exit(0);
  throw 0;  // TypeScript doesn't know that process.exit() never returns.
}


/** Gather the arguments for later use. */
const debug: boolean = argv.debug === null ? isLocalCollection : argv.debug;
const dryRun: boolean = argv['dry-run'] === null ? debug : argv['dry-run'];
const force = argv['force'];
const allowPrivate = argv['allowPrivate'];

/** Create a Virtual FS Host scoped to where the process is being run. **/
const fsHost = new virtualFs.ScopedHost(new NodeJsSyncHost(), normalize(process.cwd()));

/** Create the workflow that will be executed with this run. */
const workflow = new NodeWorkflow(fsHost, { force, dryRun });

// Indicate to the user when nothing has been done. This is automatically set to off when there's
// a new DryRunEvent.
let nothingDone = true;

// Logging queue that receives all the messages to show the users. This only get shown when no
// errors happened.
let loggingQueue: string[] = [];
let error = false;

/**
 * Logs out dry run events.
 *
 * All events will always be executed here, in order of discovery. That means that an error would
 * be shown along other events when it happens. Since errors in workflows will stop the Observable