type safeCloser struct {
	closed uint32
	r      io.Reader
}

func (s *safeCloser) Read(p []byte) (n int, err error) {
	if atomic.LoadUint32(&s.closed) == 1 {
		return 0, io.EOF
	}
	n, err = s.r.Read(p)
	if atomic.LoadUint32(&s.closed) == 1 {
		return 0, io.EOF
	}
	return n, err
}

func (s *safeCloser) Close() error {
	atomic.CompareAndSwapUint32(&s.closed, 0, 1)

	}
	close(done)
}

// Don't inline this function, since we want to test adjusting
// pointers in the arguments.
//
//go:noinline
func debugCallWorker2(stop *uint32, x *int) {
	for atomic.LoadUint32(stop) == 0 {
		// Strongly encourage x to live in a register so we
		// can test pointer register adjustment.
		*x++
	}
	*x = 1
}

func debugCallTKill(tid int) error {

	var stop uint32
	defer atomic.StoreUint32(&stop, 1) // in case of panic

	var wg sync.WaitGroup
	for i := 0; i < 4; i++ {
		wg.Add(1)
		go func() {
			for atomic.LoadUint32(&stop) == 0 {
				syscall.Close(-1)
			}
			wg.Done()
		}()
	}

	max := 10000
	if testing.Short() {
		max = 100
	}
	stk := make([]runtime.StackRecord, 128)
	for n := 0; n < max; n++ {

	// Note: these are disabled by flag_race in findIntrinsic below.
	alias("sync/atomic", "LoadInt32", "internal/runtime/atomic", "Load", all...)
	alias("sync/atomic", "LoadInt64", "internal/runtime/atomic", "Load64", all...)
	alias("sync/atomic", "LoadPointer", "internal/runtime/atomic", "Loadp", all...)
	alias("sync/atomic", "LoadUint32", "internal/runtime/atomic", "Load", all...)

		// Check that this goroutine is running on a different thread.
		self := C.pthread_self()
		if C.pthread_equal(subThread, self) != 0 {
			println("locked thread reused")
			os.Exit(1)
		}
		if atomic.LoadUint32((*uint32)(&C.threadExited)) != 0 {
			println("OK")
			return
		}
	}

	if err != nil {
		t.Fatalf("mprotect high failed %s\n", err)
	}

	// This should not fault.
	a := (*uint32)(unsafe.Pointer(&b[pagesize-4]))
	atomic.StoreUint32(a, 1)
	if x := atomic.LoadUint32(a); x != 1 {
		t.Fatalf("bad atomic value: %v, want 1", x)
	}
	if x := atomic.AddUint32(a, 1); x != 2 {
		t.Fatalf("bad atomic value: %v, want 2", x)
	}

// error
type cacheOnce struct {
	m    sync.Mutex
	done uint32
}

// Copied from sync.Once but we don't want to cache the results if there is an
// error
func (o *cacheOnce) cache(f func() error) {
	if atomic.LoadUint32(&o.done) == 1 {
		return
	}
	// Slow-path.
	o.m.Lock()
	defer o.m.Unlock()
	if o.done == 0 {
		err := f()
		if err == nil {
			atomic.StoreUint32(&o.done, 1)
		}
	}

// non-nil error is returned.
func NewWithRetry[T any](f func() (T, error)) Lazy[T] {
	return &lazyImpl[T]{getter: f, retry: true}
}

func (l *lazyImpl[T]) Get() (T, error) {
	if atomic.LoadUint32(&l.done) == 0 {
		// Outlined slow-path to allow inlining of the fast-path.
		return l.doSlow()
	}
	return l.res, l.err
}

func (l *lazyImpl[T]) doSlow() (T, error) {
	l.m.Lock()
	defer l.m.Unlock()

	if debugPrint {
		fmt.Println(c.Local, "->", c.Remote, "WaitForConnect")
		defer fmt.Println(c.Local, "->", c.Remote, "WaitForConnect done")
	}
	c.connChange.L.Lock()
	if atomic.LoadUint32((*uint32)(&c.state)) == StateConnected {
		c.connChange.L.Unlock()
		// Happy path.
		return nil
	}
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()
	changed := make(chan State, 1)
	go func() {

		Dialer:        s.Dialer,
		ListenerIP:    listenerIP,
		DisableALPN:   s.DisableALPN,
		IstioVersion:  s.IstioVersion,
	})
}

func (s *Instance) isReady() bool {
	return atomic.LoadUint32(&s.ready) == 1
}

func (s *Instance) waitUntilReady() error {
	wg := &sync.WaitGroup{}

	onEndpointReady := func() {
		wg.Done()
	}

	// Start the servers, updating port numbers as necessary.