// It may return the (non-nil) error from the same call or return the error (and n == 0) from a subsequent call.
// Callers should always process the n > 0 bytes returned before considering the error err.
// Doing so correctly handles I/O errors that happen after reading some bytes and also both of the allowed EOF behaviors.
func (r *RingBuffer) Read(p []byte) (n int, err error) {
	if len(p) == 0 {
		return 0, r.readErr(false)
	}

	r.mu.Lock()

// Validate KafkaArgs fields
func (k KafkaArgs) Validate() error {
	if !k.Enable {
		return nil
	}
	if len(k.Brokers) == 0 {
		return errors.New("no broker address found")
	}
	for _, b := range k.Brokers {
		if _, err := xnet.ParseHost(b.String()); err != nil {
			return err
		}
	}
	if k.QueueDir != "" {
		if !filepath.IsAbs(k.QueueDir) {
			return errors.New("queueDir path should be absolute")
		}
	}

}

// Validate NSQArgs fields
func (n NSQArgs) Validate() error {
	if !n.Enable {
		return nil
	}

	if n.NSQDAddress.IsEmpty() {
		return errors.New("empty nsqdAddress")
	}

	if n.Topic == "" {
		return errors.New("empty topic")
	}
	if n.QueueDir != "" {
		if !filepath.IsAbs(n.QueueDir) {
			return errors.New("queueDir path should be absolute")
		}
	}

	return nil
}

}

func (c *kmsConn) CreateKey(ctx context.Context, req *CreateKeyRequest) error {
	if err := c.client.CreateKey(ctx, &kms.CreateKeyRequest{
		Enclave: c.enclave,
		Name:    req.Name,
	}); err != nil {
		if errors.Is(err, kms.ErrKeyExists) {
			return ErrKeyExists
		}
		if errors.Is(err, kms.ErrPermission) {
			return ErrPermission
		}
		return errKeyCreationFailed(err)
	}

	if err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}

	n, err = base64DecodeBytes(token[i+1:j], buf)
	if err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}

	if err = claims.UnmarshalJSON(buf[:n]); err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}

// Check if an API error is properly defined
func TestAPIErrCodeDefinition(t *testing.T) {
	for errAPI := ErrNone + 1; errAPI < apiErrCodeEnd; errAPI++ {
		errCode, ok := errorCodes[errAPI]
		if !ok {
			t.Fatal(errAPI, "error code is not defined in the API error code table")
		}
		if errCode.Code == "" {
			t.Fatal(errAPI, "error code has an empty XML code")
		}
		if errCode.HTTPStatusCode == 0 {

}

func diskErrToDriveState(err error) (state string) {
	switch {
	case errors.Is(err, errDiskNotFound) || errors.Is(err, context.DeadlineExceeded):
		state = madmin.DriveStateOffline
	case errors.Is(err, errCorruptedFormat) || errors.Is(err, errCorruptedBackend):
		state = madmin.DriveStateCorrupt
	case errors.Is(err, errUnformattedDisk):
		state = madmin.DriveStateUnformatted
	case errors.Is(err, errDiskAccessDenied):

			}
		}
	}
	return
}

func validateTableName(from *TableExpression) error {
	if !strings.EqualFold(from.Table.BaseKey.String(), baseTableName) {
		return errBadTableName(errors.New("table name must be `s3object`"))
	}

	if len(from.Table.PathExpr) > 0 {
		if !from.Table.PathExpr[0].ArrayWildcard {
			return errBadTableName(errors.New("keypath table name is invalid - please check the service documentation"))
		}
	}

}

// Standard errors.
var (
	ErrNotImplemented     = errors.New("function not implemented")
	ErrAccessTokenExpired = errors.New("access_token expired or unauthorized")
)

// Provider implements identity provider specific admin operations, such as
// looking up users, fetching additional attributes etc.
type Provider interface {
	LoginWithUser(username, password string) error

	globalLocalDrivesMu.RUnlock()

	errs := make([]error, len(localDrives))
	infos := make([]DiskInfo, len(localDrives))
	for i, drive := range localDrives {
		infos[i], errs[i] = drive.DiskInfo(GlobalContext, DiskInfoOptions{})
	}
	infoMaps := make(map[string]madmin.DiskMetrics)
	for i := range infos {
		if infos[i].Metrics.TotalWaiting >= 1 && errors.Is(errs[i], errFaultyDisk) {