[#595] Simplify encryption.Params struct

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

api/handler/put.go

@@ -334,7 +334,12 @@ func (h handler) formEncryptionParams(header http.Header) (enc encryption.Params
 		return enc, errors.GetAPIError(errors.ErrSSECustomerKeyMD5Mismatch)
 	}
 
-	return encryption.NewParams(key)
+	params, err := encryption.NewParams(key)
+	if err == nil {
+		enc = *params
+	}
+
+	return enc, err
 }
 
 func (h *handler) PostObject(w http.ResponseWriter, r *http.Request) {

api/layer/encryption/encryption.go

@@ -15,7 +15,6 @@ import (
 
 // Params contains encryption key info.
 type Params struct {
-	enabled     bool
 	customerKey []byte
 }
 
@@ -66,25 +65,24 @@ const (
 )
 
 // NewParams creates new params to encrypt with provided key.
-func NewParams(key []byte) (Params, error) {
-	var p Params
+func NewParams(key []byte) (*Params, error) {
 	if len(key) != aes256KeySize {
-		return p, fmt.Errorf("invalid key size: %d", len(key))
+		return nil, fmt.Errorf("invalid key size: %d", len(key))
 	}
-	p.enabled = true
+	var p Params
 	p.customerKey = make([]byte, aes256KeySize)
 	copy(p.customerKey, key)
-	return p, nil
+	return &p, nil
 }
 
-// Key returns encryption key as slice.
+// Key returns encryption key.
 func (p Params) Key() []byte {
-	return p.customerKey[:]
+	return p.customerKey
 }
 
 // Enabled returns true if key isn't empty.
 func (p Params) Enabled() bool {
-	return p.enabled
+	return len(p.customerKey) > 0
 }
 
 // HMAC computes salted HMAC.

api/layer/encryption/encryption_test.go

@@ -58,7 +58,7 @@ func getDecrypter(t *testing.T) *Decrypter {
 
 	return &Decrypter{
 		parts:      parts,
-		encryption: params,
+		encryption: *params,
 	}
 }