@Override
  AbstractFuture<@Nullable Integer> newDelegate() {
    AbstractFuture<@Nullable Integer> future = new TrustedFuture<@Nullable Integer>() {};
    assertTrue(future instanceof TrustedFuture); // sanity check
    return future;
  }

    }

    final SettableFuture<V> delegate = SettableFuture.create();

    @Override
    protected Future<V> delegate() {
      return delegate;
    }

    void set(V value) {
      delegate.set(value);
    }
  }

  private static final class RuntimeExceptionThrowingFuture<V> implements Future<V> {
    final CountDownLatch allowGetToComplete = new CountDownLatch(1);

    @Override

    super.releaseResources(reason);
    /*
     * If the output future is done, then it won't need to interrupt the task later, so it can clear
     * its reference to it.
     *
     * If the output future is *not* done, then the task field will be cleared after the task runs
     * or after the output future is done, whichever comes first.
     */
    if (reason == OUTPUT_FUTURE_DONE) {
      this.task = null;

    CountDownLatch latch = new CountDownLatch(1);
    SettableFuture<?> future = SettableFuture.create();
    Executor delegate =
        new Executor() {
          @Override
          public void execute(Runnable task) {
            if (future.set(null)) {
              awaitUninterruptibly(latch);
            }
            throw new RejectedExecutionException();

  @Override
  AbstractFuture<@Nullable Integer> newDelegate() {
    AbstractFuture<@Nullable Integer> future = new TrustedFuture<@Nullable Integer>() {};
    assertTrue(future instanceof TrustedFuture); // sanity check
    return future;
  }

  @Override
  AbstractFuture<@Nullable Integer> newDelegate() {
    AbstractFuture<@Nullable Integer> future = new AbstractFuture<@Nullable Integer>() {};
    assertFalse(future instanceof TrustedFuture); // sanity check
    return future;
  }

  }

  /**
   * Waits until the given future {@linkplain Future#isDone is done}, invoking the garbage collector
   * as necessary to try to ensure that this will happen.
   *
   * @throws RuntimeException if timed out or interrupted while waiting
   */
  @SuppressWarnings("removal") // b/487687332
  public static void awaitDone(Future<?> future) {
    if (future.isDone()) {
      return;
    }

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

    Listener old = listeners;
    listeners = update;
    return old;
  }

  static boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {
    if (future.value == expect) {
      future.value = update;
      return true;
    }
    return false;
  }

  final @Nullable Object value() {
    return value;
  }

   *       return value of this method as its cause
   * </ul>
   */
  public static
      Throwable
      tryInternalFastPathGetFailure(InternalFutureFailureAccess future) {
    return future.tryInternalFastPathGetFailure();
  }

  private InternalFutures() {}