Function update one now considers the protection key using the update operator

mongox/base/protection/key.go

@@ -3,6 +3,7 @@ package protection
 import (
 	"time"
 
+	"github.com/modern-go/reflect2"
 	"go.mongodb.org/mongo-driver/bson/primitive"
 )
 
@@ -12,6 +13,22 @@ type Key struct {
 	V int64              `bson:"_v" json:"_v"`
 }
 
+// PutToDocument extends the doc with protection key values
+func (k *Key) PutToDocument(doc primitive.M) {
+
+	if reflect2.IsNil(doc) {
+		return
+	}
+
+	if k.X.IsZero() {
+		doc["_x"] = primitive.M{"$exists": false}
+		doc["_v"] = primitive.M{"$exists": false}
+	} else {
+		doc["_x"] = k.X
+		doc["_v"] = k.V
+	}
+}
+
 // Restate creates a new protection key
 func (k *Key) Restate() {
 	k.X = primitive.NewObjectID()