// if it is not successful yet.
func (l *Init) Do(f func() error) error {
	if atomic.LoadUint32(&l.done) == 0 {
		return l.do(f)
	}
	return nil
}

func (l *Init) do(f func() error) error {
	l.m.Lock()
	defer l.m.Unlock()
	if atomic.LoadUint32(&l.done) == 0 {
		if err := f(); err != nil {
			return err
		}
		// Mark as done only when f() is successful
		atomic.StoreUint32(&l.done, 1)
	}
	return nil
}

// AddSystemTarget adds a new logger target to the
// list of enabled loggers
func AddSystemTarget(ctx context.Context, t Target) error {
	if err := t.Init(ctx); err != nil {
		return err
	}

	swapSystemMuRW.Lock()
	defer swapSystemMuRW.Unlock()

	if consoleTgt == nil {
		if t.Type() == types.TargetConsole {
			consoleTgt = t
		}
	}
	updated := append(make([]Target, 0, len(systemTargets)+1), systemTargets...)

	go func() {
		r := rand.New(rand.NewSource(time.Now().UnixNano()))
		// Leader node (that successfully acquires the lock inside licenceUpdaterLoop)
		// will keep performing the license update. If the leader goes down for some
		// reason, the lock will be released and another node will acquire it and
		// take over because of this loop.
		for {
			licenceUpdaterLoop(ctx, objAPI)

	globalAuthPluginMutex.Lock()
	defer globalAuthPluginMutex.Unlock()
	return globalAuthNPlugin
}

func newGlobalAuthZPluginFn() *polplugin.AuthZPlugin {
	globalAuthPluginMutex.Lock()
	defer globalAuthPluginMutex.Unlock()
	return globalAuthZPlugin
}

func setGlobalAuthNPlugin(authn *idplugin.AuthNPlugin) {
	globalAuthPluginMutex.Lock()
	globalAuthNPlugin = authn

func (srv *Server) Shutdown() error {
	srv.listenerMutex.Lock()
	if srv.listener == nil {
		srv.listenerMutex.Unlock()
		return http.ErrServerClosed
	}
	srv.listenerMutex.Unlock()

	if atomic.AddUint32(&srv.inShutdown, 1) > 1 {
		// shutdown in progress
		return http.ErrServerClosed
	}

	// Close underneath HTTP listener.
	srv.listenerMutex.Lock()
	err := srv.listener.Close()
	srv.listenerMutex.Unlock()

	if err != nil {
		t.Fatal(err)
	}

	erasureDisks := xl.getDisks()
	z.serverPools[0].erasureDisksMu.Lock()
	xl.getDisks = func() []StorageAPI {
		for i := range erasureDisks[:6] {
			erasureDisks[i] = newNaughtyDisk(erasureDisks[i], nil, errFaultyDisk)
		}
		return erasureDisks
	}

	// Open journal if it hasn't been
	err := jd.Open()
	if err != nil {
		return err
	}

	b, err := je.MarshalMsg(nil)
	if err != nil {
		return err
	}

	jd.Lock()
	defer jd.Unlock()
	_, err = jd.file.Write(b)
	if err != nil {
		// Do not leak fd here, close the file properly.
		Fdatasync(jd.file)
		_ = jd.file.Close()

type TargetList struct {
	sync.RWMutex
	targets map[TargetID]Target
}

// Add - adds unique target to target list.
func (list *TargetList) Add(targets ...Target) error {
	list.Lock()
	defer list.Unlock()

	for _, target := range targets {
		if _, ok := list.targets[target.ID()]; ok {
			return fmt.Errorf("target %v already exists", target.ID())
		}
		list.targets[target.ID()] = target
	}

	defer func() {
		if unlockOnDefer {
			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := z.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()
		nsUnlocker = func() { lock.RUnlock(lkctx) }
		unlockOnDefer = true
	}

	checkPrecondFn := opts.CheckPrecondFn

	if err != nil {
		return err
	}
	defer resp.Body.Close()

	var accessToken Token
	if err = json.NewDecoder(resp.Body).Decode(&accessToken); err != nil {
		return err
	}

	k.Lock()
	k.accessToken = accessToken
	k.Unlock()
	return nil
}

// LookupUser lookup user by their userid.
func (k *KeycloakProvider) LookupUser(userid string) (User, error) {