}

// Matches returns whether given content matches c.
func (c Checksum) Matches(content []byte) error {
	if len(c.Encoded) == 0 {
		return nil
	}
	hasher := c.Type.Hasher()
	_, err := hasher.Write(content)
	if err != nil {
		return err
	}
	sum := hasher.Sum(nil)
	if !bytes.Equal(sum, c.Raw) {
		return ChecksumMismatch{
			Want: c.Encoded,
			Got:  base64.StdEncoding.EncodeToString(sum),
		}
	}

	t := time.Now().Unix()
	e.init.Do(func() {
		e.cached.Store(&AccElem{})
		atomic.StoreInt64(&e.cachedSec, t)
	})
	acc := e.cached.Load()
	if lastT := atomic.LoadInt64(&e.cachedSec); lastT != t {
		// Check if lastT was changed by someone else.
		if atomic.CompareAndSwapInt64(&e.cachedSec, lastT, t) {
			// Now we swap in a new.
			newAcc := &AccElem{}
			old := e.cached.Swap(newAcc)
			var a AccElem

	got, err := scanDataFolder(context.Background(), nil, base, dataUsageCache{Info: dataUsageCacheInfo{Name: "bucket"}}, getSize, 0, weSleep)
	if err != nil {
		t.Fatal(err)
	}
	if got.root() == nil {
		t.Log("cached folders:")
		for folder := range got.Cache {
			t.Log("folder:", folder)
		}
		t.Fatal("got nil root.")
	}

	// Test dirs
	want := []struct {
		path       string
		isNil      bool

	entityKeysInStorage := set.NewStringSet()
	if iamOS, ok := sys.store.IAMStorageAPI.(*IAMObjectStore); ok {
		// Load existing mapping keys from the cached listing for
		// `IAMObjectStore`.
		iamFilesListing := iamOS.cachedIAMListing.Load().(map[string][]string)
		listKey := policyDBSTSUsersListKey
		if isGroup {
			listKey = policyDBGroupsListKey
		}

// that all buckets are present on all serverPools.
func (z *erasureServerPools) ListBuckets(ctx context.Context, opts BucketOptions) (buckets []BucketInfo, err error) {
	if opts.Cached {
		listBucketsCache.InitOnce(time.Second,
			cachevalue.Opts{ReturnLastGood: true, NoWait: true},
			func() ([]BucketInfo, error) {
				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)

	}
	for k, v := range m.VariableLabels {
		metric.VariableLabels[k] = v
	}
	for k, v := range m.Histogram {
		metric.Histogram[k] = v
	}
	return metric
}

// Get - returns cached value always upton the configured TTL,
// once the TTL expires "read()" registered function is called
// to return the new values and updated.
func (g *MetricsGroupV2) Get() (metrics []MetricV2) {

						w.WriteHeader(ci.StatusCode)
						return
					}

					// We did not satisfy any requirement from the cache, update the cache.
					// this basically means that we do not have the Data for the object
					// cached yet
					update = true
				})
				if !update {
					// No update is needed means we have written already to the client just return here.
					return
				}
			}
		}

	"sync/atomic"
	"time"
)

// Opts contains options for the cache.
type Opts struct {
	// When set to true, return the last cached value
	// even if updating the value errors out.
	// Returns the last good value AND the error.
	ReturnLastGood bool

	// If CacheError is set, errors will be cached as well
	// and not continuously try to update.
	// Should not be combined with ReturnLastGood.
	CacheError bool

		return selected, true
	}

	// If cached is nil we shall skip the entry.
	if selected.cached == nil {
		return nil, false
	}

	// Merge if we have disagreement.
	// Create a new merged result.
	selected = &metaCacheEntry{
		name:     selected.name,
		reusable: true,
		cached:   &xlMetaV2{metaV: selected.cached.metaV},
	}

		if len(dui.BucketsUsage) > 0 {
			internalLogOnceIf(GlobalContext, fmt.Errorf("unable to retrieve usage information for bucket: %s, relying on older value cached in-memory: err(%v)", bucket, err), "bucket-usage-cache-"+bucket)
		} else {