version compat system

proto/smart_convert.go

@@ -0,0 +1,42 @@
+package proto
+
+import (
+	"reflect"
+)
+
+func SmartConvertibleTo(from, to reflect.Type) bool {
+	switch from.Kind() {
+	case reflect.Struct:
+		if from.NumField() != to.NumField() {
+			return false
+		}
+		for i := range from.NumField() {
+			if !SmartConvertibleTo(from.Field(i).Type, to.Field(i).Type) {
+				return false
+			}
+		}
+		return true
+	case reflect.Ptr:
+		return SmartConvertibleTo(from.Elem(), to.Elem())
+	default:
+		return from.ConvertibleTo(to)
+	}
+}
+
+func SmartConvert(from reflect.Value, to reflect.Type) (ret reflect.Value) {
+	switch from.Kind() {
+	case reflect.Struct:
+		ret = reflect.New(to).Elem()
+		for i := range from.NumField() {
+			ret.Field(i).Set(SmartConvert(from.Field(i), to.Field(i).Type))
+		}
+		return ret
+	case reflect.Ptr:
+		if from.IsNil() {
+			return reflect.Zero(to)
+		}
+		return SmartConvert(from.Elem(), to.Elem()).Addr()
+	default:
+		return from.Convert(to)
+	}
+}