Prepare for v3

mongox/base/protection/key.go

@@ -1,6 +1,7 @@
 package protection
 
 import (
+	"reflect"
 	"time"
 
 	"github.com/modern-go/reflect2"
@@ -13,9 +14,8 @@ type Key struct {
 	V int64              `bson:"_v" json:"_v"`
 }
 
-// PutToDocument extends the doc with protection key values
-func (k *Key) PutToDocument(doc primitive.M) {
-
+// Inject extends the doc with protection key values
+func (k *Key) Inject(doc primitive.M) {
 	if reflect2.IsNil(doc) {
 		return
 	}
@@ -34,3 +34,35 @@ func (k *Key) Restate() {
 	k.X = primitive.NewObjectID()
 	k.V = time.Now().Unix()
 }
+
+// Get finds protection field in the source document otherwise returns nil
+func Get(source interface{}) (key *Key) {
+	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)
+		if !field.CanInterface() {
+			continue
+		}
+
+		switch field.Interface().(type) {
+		case *Key:
+			key = field.Interface().(*Key)
+		case Key:
+			ptr := field.Addr()
+			key = ptr.Interface().(*Key)
+		default:
+			continue
+		}
+
+		return key
+	}
+
+	return nil
+}

mongox/base/protection/key_test.go

@@ -0,0 +1,3 @@
+package protection_test
+
+// TODO: