@@ -19,6 +19,8 @@ import (

 // For more information see: http://sourceforge.net/p/aufs/aufs3-standalone/ci/aufs3.12/tree/config.mk

 const MaxImageDepth = 127

+var validHex = regexp.MustCompile(`^([a-f0-9]{64})$`)

+

 type Image struct {

 	ID              string            `json:"id"`

 	Parent          string            `json:"parent,omitempty"`

@@ -266,7 +268,6 @@ func NewImgJSON(src []byte) (*Image, error) {

 // Check wheather id is a valid image ID or not

 func ValidateID(id string) error {

-	validHex := regexp.MustCompile(`^([a-f0-9]{64})$`)

 	if ok := validHex.MatchString(id); !ok {

 		return fmt.Errorf("image ID '%s' is invalid", id)

 	}