* 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;
        this.currentFuture = currentFuture;
      }

     * 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;
        this.currentFuture = currentFuture;
      }

        lock.readLock().lock();
        try {
            lastAccessTime = System.currentTimeMillis();
            return children.get(name);
        } finally {
            lock.readLock().unlock();
        }
    }
    
    public boolean hasChild(String name) {
        lock.readLock().lock();
        try {
            lastAccessTime = System.currentTimeMillis();
            return children.containsKey(name);

        "fe012443-6ba9-4ef2-bb94-b729d2060c78/test123/testw3c.pdf/xl.meta": {"Versions":[{"Type":1,"V2Obj":{"ID":"aGEA/ZUOR4ueRIZs...

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/** Forwarding wrapper around a {@code Lock}. */
@J2ktIncompatible
@GwtIncompatible
abstract class ForwardingLock implements Lock {
  abstract Lock delegate();

  @Override
  public void lock() {
    delegate().lock();
  }

  @Override

 */
package jcifs.internal.smb2.lock;

import jcifs.Encodable;
import jcifs.internal.util.SMBUtil;

/**
 * SMB2 Lock data structure.
 *
 * This class represents a single lock element used in
 * SMB2 Lock requests for byte-range locking.
 *
 * @author mbechler
 */
public class Smb2Lock implements Encodable {

    /**
     * Flag indicating a shared lock that allows concurrent read access.
     */

	}
}

// Test lock race
func TestNSLockRace(t *testing.T) {
	t.Skip("long test skip it")

	ctx := t.Context()

	for i := range 10000 {
		nsLk := newNSLock(false)

		// lk1; ref=1
		if !nsLk.lock(ctx, "volume", "path", "source", "opsID", false, time.Second) {
			t.Fatal("failed to acquire lock")
		}

		// lk2
		lk2ch := make(chan struct{})
		go func() {

   */
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {
      endTask();
    }
  }

  @Override
  public boolean isShutdown() {
    synchronized (lock) {
      return shutdown;
    }
  }

  }

  /**
   * Invokes {@code lock.}{@link Lock#tryLock(long, TimeUnit) tryLock(timeout, unit)}
   * uninterruptibly.
   *
   * @since 30.0
   */
  @J2ktIncompatible
  @GwtIncompatible // concurrency
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public static boolean tryLockUninterruptibly(Lock lock, long timeout, TimeUnit unit) {

	// works, but only when running one binary at a time.
	// Use a file lock to make sure only one wrapper is running at a time.
	//
	// The lock file is never deleted, to avoid concurrent locks on distinct
	// files with the same path.
	lockName := filepath.Join(os.TempDir(), "go_ios_exec-"+deviceID+".lock")
	lock, err = os.OpenFile(lockName, os.O_CREATE|os.O_RDONLY, 0666)
	if err != nil {
		return 1, err
	}