[#209] object: Support splitID search attribute

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/object/splitid.go

@@ -0,0 +1,59 @@
+package object
+
+import (
+	"github.com/google/uuid"
+)
+
+// SplitID is a UUIDv4 used as attribute in split objects.
+type SplitID struct {
+	uuid uuid.UUID
+}
+
+// NewSplitID returns UUID representation of splitID attribute.
+func NewSplitID() *SplitID {
+	return &SplitID{
+		uuid: uuid.New(),
+	}
+}
+
+// NewSplitIDFromV2 returns parsed UUID from bytes.
+// If v is invalid UUIDv4 byte sequence, then function returns nil.
+func NewSplitIDFromV2(v []byte) *SplitID {
+	id := uuid.New()
+
+	err := id.UnmarshalBinary(v)
+	if err != nil {
+		return nil
+	}
+
+	return &SplitID{
+		uuid: id,
+	}
+}
+
+// Parse converts UUIDv4 string representation into SplitID.
+func (id *SplitID) Parse(s string) (err error) {
+	id.uuid, err = uuid.Parse(s)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// String returns UUIDv4 string representation of SplitID.
+func (id SplitID) String() string {
+	return id.uuid.String()
+}
+
+// SetUUID sets pre created UUID structure as SplitID.
+func (id *SplitID) SetUUID(v uuid.UUID) {
+	id.uuid = v
+}
+
+// ToV2 converts SplitID to a representation of SplitID in neofs-api v2.
+func (id SplitID) ToV2() []byte {
+	data, _ := id.uuid.MarshalBinary() // err is always nil
+
+	return data
+}