Protection structure

mongox/base/getprotection.go

@@ -0,0 +1,33 @@
+package base
+
+import (
+	"reflect"
+)
+
+// GetProtection function finds protection field in the source document otherwise returns nil
+func GetProtection(source interface{}) *Protection {
+
+	v := reflect.ValueOf(source)
+	if v.Kind() != reflect.Ptr || v.IsNil() {
+		return nil
+	}
+
+	el := v.Elem()
+	numField := el.NumField()
+
+	for i := 0; i < numField; i++ {
+		field := el.Field(i)
+
+		switch field.Interface().(type) {
+		case *Protection:
+			return field.Interface().(*Protection)
+		case Protection:
+			ptr := field.Addr()
+			return ptr.Interface().(*Protection)
+		default:
+			continue
+		}
+	}
+
+	return nil
+}

mongox/base/protection.go

@@ -0,0 +1,11 @@
+package base
+
+import (
+	"github.com/mongodb/mongo-go-driver/bson/primitive"
+)
+
+// Protection field stores unique document id and version
+type Protection struct {
+	X primitive.ObjectID `bson:"_x" json:"_x" index:",hashed"`
+	V int64              `bson:"_v" json:"_v"`
+}