LibTest/io/Directory/watch_A02_t01.dart

// Copyright (c) 2017, 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.

/**
 * @assertion Stream<FileSystemEvent> watch({
 *  int events: FileSystemEvent.ALL,
 *  bool recursive: false
 *  })
 * The implementation uses platform-dependent event-based APIs for receiving
 * file-system notifications, thus behavior depends on the platform.
 *
 * Windows: Uses ReadDirectoryChangesW. The implementation only supports
 * watching directories. Recursive watching is supported.
 * Linux: Uses inotify. The implementation supports watching both files and
 * directories. Recursive watching is not supported. Note: When watching files
 * directly, delete events might not happen as expected.
 * OS X: Uses FSEvents. The implementation supports watching both files and
 * directories. Recursive watching is supported.
 *
 * The system will start listening for events once the returned Stream is being
 * listened to, not when the call to watch is issued.
 *
 * The returned value is an endless broadcast Stream, that only stops when one
 * of the following happens:
 * The Stream is canceled, e.g. by calling cancel on the StreamSubscription.
 * The FileSystemEntity being watched, is deleted.
 * System Watcher exits unexpectedly. e.g. On Windows this happens when buffer
 * that receive events from ReadDirectoryChangesW overflows.
 * Use events to specify what events to listen for. The constants in
 * FileSystemEvent can be or'ed together to mix events. Default is
 * FileSystemEvent.ALL.
 *
 * A move event may be reported as separate delete and create events.
 * @description Checks that this method watches the FileSystemEntity for
 * changes. Test recursive parameter
 * @author sgrekhov@unipro.ru
 */
import "dart:io";
import "dart:async";
import "../../../Utils/expect.dart";
import "../file_utils.dart";

main() async {
  if (!Platform.isLinux) {
    await inSandbox(_main);
  }
}

_main(Directory sandbox) async {
  Directory dir = getTempDirectorySync(parent: sandbox);
  Directory child = dir.createTempSync();

  final eventCompleter = new Completer<FileSystemEvent?>();
  StreamSubscription? subscription;
  asyncStart();
  subscription = dir.watch(events: FileSystemEvent.create,
      recursive: true).listen((FileSystemEvent event) async {
    eventCompleter.complete(event);
    await subscription?.cancel();
    if (event.type != FileSystemEvent.create) {
      Expect.fail("Wrong event arrived");
    } else {
      asyncEnd();
    }
  });
  child.createTempSync();

  await eventCompleter.future
      .timeout(Duration(seconds: eventsTimeout), onTimeout: () async {
    await subscription?.cancel();
    Expect.fail("Watch timed out");
  });
}