*
   * (Perhaps it should also have required that its cause was a RuntimeException. However, that
   * would have required that we throw a different kind of exception for wrapping *checked*
   * exceptions in methods like Futures.getUnchecked and LoadingCache.get.)
   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *

   * Future} instances to be upgraded to {@code ListenableFuture} after the fact.
   */
  public static <V extends @Nullable Object> ListenableFuture<V> listenInPoolThread(
      Future<V> future) {
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future);
  }

  /**

 */

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.Callables.returning;
import static com.google.common.util.concurrent.Futures.getDone;
import static com.google.common.util.concurrent.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.util.concurrent.TestPlatform.verifyThreadWasNotInterrupted;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import org.jspecify.annotations.Nullable;

/** Implementation of {@link Futures#immediateFuture}. */
@GwtCompatible
// TODO(cpovirk): Make this final (but that may break Mockito spy calls).
class ImmediateFuture<V extends @Nullable Object> implements ListenableFuture<V> {

  }

  void assertThatFutureFailsWithException(Future<?> future) {
    try {
      getUninterruptibly(future);
      fail("Expected future to fail: " + future);
    } catch (ExecutionException e) {
      assertThat(e).hasCauseThat().isSameInstanceAs(exception);
    }
  }

  static void assertThatFutureBecomesCancelled(Future<?> future) throws ExecutionException {
    try {

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@code Futures#withTimeout}.
 *

        if (future.listenersField == expect) {
          future.listenersField = update;
          return true;
        }
        return false;
      }
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      synchronized (future) {
        Listener old = future.listenersField;
        if (old != update) {
          future.listenersField = update;

        if (future.listenersField == expect) {
          future.listenersField = update;
          return true;
        }
        return false;
      }
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      synchronized (future) {
        Listener old = future.listenersField;
        if (old != update) {
          future.listenersField = update;

    /**
     * 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;

import static com.google.common.cache.TestingRemovalListeners.countingRemovalListener;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;