LibTest/io/RandomAccessFile/lock_A05_t02.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
 * Future<RandomAccessFile> lock([
 *     FileLock mode = FileLock.exclusive,
 *     int start = 0,
 *     int end = -1
 * ])
 * . . .
 * NOTE file locking does have slight differences in behavior across platforms:
 *
 * On Linux and OS X this uses advisory locks, which have the surprising
 * semantics that all locks associated with a given file are removed when any
 * file descriptor for that file is closed by the process. Note that this does
 * not actually lock the file for access. Also note that advisory locks are on
 * a process level. This means that several isolates in the same process can
 * obtain an exclusive lock on the same file.
 *
 * On Windows the regions used for lock and unlock needs to match. If that is
 * not the case unlocking will result in the OS error "The segment is already
 * unlocked".
 *
 * @description Checks that on Linux and OS X all locks associated with a given
 * file are removed when any file descriptor for that file is closed by the
 * process.
 * @author ngl@unipro.ru
 */
import "dart:async";
import "dart:io";
import "../../../Utils/expect.dart";
import "../file_utils.dart";
import "lock_check_1_lib.dart";

main() {
  int fLen = 10;
  File file = getTempFileSync();
  asyncStart();
  var rf1 = file.openSync(mode: FileMode.write);
  var rf2 = file.openSync(mode: FileMode.write);
  for (int i = 0; i < fLen; i++) {
    rf1.writeByteSync((i + 1) & 0xff);
  }
  var rfLock = rf1.lock(FileLock.exclusive, 4, 6);
  rf2.lockSync(FileLock.exclusive, 7, 8);
  rfLock.then((RandomAccessFile f) {
    rf2.closeSync();
    var tests = [];
    if (!Platform.isWindows) {
      tests.addAll([
        () => checkUnlocked(file.path),
      ]);
    } else {
      tests.addAll([
        () => rf1.unlockSync(4, 6),
        () => rf2.unlockSync(7, 8),
        () => checkUnlocked(file.path)
      ]);
    }
    Future.forEach(tests, (f) => f()).whenComplete(() {
      asyncEnd();
      rf1.closeSync();
      file.deleteSync();
    });
  });
}