OnDemandFileAccess lock
    File file

    def setup() {
        file = dir.file("some-target-file")
        lock = new OnDemandFileAccess(file, "some-lock", manager)
    }

    def "acquires shared lock to read file"() {
        def action = {} as Supplier

        when:
        lock.readFile(action)

        then:
        !file.exists()

                    coordinationService.withStateLock(lock(sharedResourceLock))
                    assert lockIsHeld(sharedResourceLock)
                    acquired.countDown()
                    acquired.await()
                    coordinationService.withStateLock(unlock(sharedResourceLock))
                }
            }
        }

        then:
        noExceptionThrown()
    }

	var (
		v          V
		ok         bool
		done       bool
		yieldNext  bool
		racer      int
		panicValue any
		seqDone    bool // to detect Goexit
	)
	c := newcoro(func(c *coro) {
		race.Acquire(unsafe.Pointer(&racer))
		if done {
			race.Release(unsafe.Pointer(&racer))
			return
		}
		yield := func(v1 V) bool {
			if done {
				return false
			}
			if !yieldNext {

	// of the wait queue. If a waiter fails to acquire the mutex for more than 1ms,
	// it switches mutex to the starvation mode.
	//
	// In starvation mode ownership of the mutex is directly handed off from
	// the unlocking goroutine to the waiter at the front of the queue.
	// New arriving goroutines don't try to acquire the mutex even if it appears

        return locks.findAll { it.locked }.collect { it.project } as Set
    }

    protected void recordLocks(Closure cl) {
        acquired.clear()
        cl()
        acquired.clear()
    }

    protected ProjectInternal project(ProjectInternal parent = null, String name = "root") {
        def projectState = Mock(ProjectState)

        def project = Mock(ProjectInternal, name: name)

func (g *execGroup) Go(ctx context.Context, work func() error) {
	g.g.Go(func() error {
		g.e.totalRequests.Inc()
		g.e.activeRequests.Inc()
		defer g.e.activeRequests.Dec()

		// Acquire the group concurrency semaphore.
		if err := g.sem.Acquire(ctx, 1); err != nil {
			return fmt.Errorf("request set timed out: %v", err)
		}
		defer g.sem.Release(1)

		return work()
	})
}

func (g *execGroup) Wait() *multierror.Error {

    def cacheAccess = new FixedExclusiveModeCrossProcessCacheAccess("<cache>", file, DefaultLockOptions.mode(FileLockManager.LockMode.Exclusive), lockManager, initAction, onOpenAction, onCloseAction)

    def "acquires lock then validates cache and runs handler action on open"() {
        def lock = Mock(FileLock)

        when:
        cacheAccess.open()

        then:
        1 * lockManager.lock(file, _, _, "", _) >> lock

    /**
     * Runs the given {@link Factory} while the specified locks are released and the given new lock is acquired. On completion,
     * the new lock is released and the old locks reacquired.
     * If a lock cannot be immediately (re)acquired, the current worker lease will be released and the method will block until the locks are (re)acquired.
     */

                return FileLockOutcome.LOCKED_BY_ANOTHER_PROCESS;
            } else {
                return FileLockOutcome.acquired(fileLock);
            }
        } catch (OverlappingFileLockException e) {
            // Locked by this process, treat as not acquired
            return FileLockOutcome.LOCKED_BY_THIS_PROCESS;
        }
    }

	// This would more properly use &getg().labels as the sync address,
	// but we do the read in a signal handler and can't call the race runtime then.
	//
	// This uses racereleasemerge rather than just racerelease so
	// the acquire in profBuf.read synchronizes with *all* prior
	// setProfLabel operations, not just the most recent one. This
	// is important because profBuf.read will observe different
	// labels set by different setProfLabel operations on