add more checks

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

util/reflect/struct.go

@@ -25,6 +25,48 @@ type StructField struct {
 	Field reflect.StructField
 }
 
+// StructFieldNameByTag get struct field name by tag key and its value
+func StructFieldNameByTag(src interface{}, tkey string, tval string) (string, interface{}, error) {
+	sv := reflect.ValueOf(src)
+	if sv.Kind() == reflect.Ptr {
+		sv = sv.Elem()
+	}
+	if sv.Kind() != reflect.Struct {
+		return "", nil, ErrInvalidStruct
+	}
+
+	typ := sv.Type()
+	for idx := 0; idx < typ.NumField(); idx++ {
+		fld := typ.Field(idx)
+		val := sv.Field(idx)
+		if len(fld.PkgPath) != 0 {
+			continue
+		}
+
+		if ts, ok := fld.Tag.Lookup(tkey); ok {
+			for _, p := range strings.Split(ts, ",") {
+				if p == tval {
+					return fld.Name, val.Interface(), nil
+				}
+			}
+		}
+
+		switch val.Kind() {
+		case reflect.Ptr:
+			if val = val.Elem(); val.Kind() == reflect.Struct {
+				if name, fld, err := StructFieldNameByTag(val.Interface(), tkey, tval); err == nil {
+					return name, fld, nil
+				}
+			}
+		case reflect.Struct:
+			if name, fld, err := StructFieldNameByTag(val.Interface(), tkey, tval); err == nil {
+				return name, fld, nil
+			}
+		}
+	}
+	return "", nil, ErrNotFound
+}
+
 // StructFieldByTag get struct field by tag key and its value
 func StructFieldByTag(src interface{}, tkey string, tval string) (interface{}, error) {
 	sv := reflect.ValueOf(src)
@@ -46,9 +88,6 @@ func StructFieldByTag(src interface{}, tkey string, tval string) (interface{}, e
 		if ts, ok := fld.Tag.Lookup(tkey); ok {
 			for _, p := range strings.Split(ts, ",") {
 				if p == tval {
-					if val.Kind() != reflect.Ptr && val.CanAddr() {
-						val = val.Addr()
-					}
 					return val.Interface(), nil
 				}
 			}
@@ -72,10 +111,21 @@ func StructFieldByTag(src interface{}, tkey string, tval string) (interface{}, e
 
 // ZeroFieldByPath clean struct field by its path
 func ZeroFieldByPath(src interface{}, path string) error {
+	if src == nil {
+		return nil
+	}
 	var err error
 	val := reflect.ValueOf(src)
 
+	if IsEmpty(val) {
+		return nil
+	}
+
 	for _, p := range strings.Split(path, ".") {
+		if IsEmpty(val) {
+			return nil
+		}
+
 		val, err = structValueByName(val, p)
 		if err != nil {
 			return err
@@ -493,13 +543,14 @@ func btSplitter(str string) []string {
 }
 
 // queryToMap turns something like a[b][c]=4 into
-//   map[string]interface{}{
-//     "a": map[string]interface{}{
-// 		  "b": map[string]interface{}{
-// 			  "c": 4,
-// 		  },
-// 	  },
-//   }
+//
+//	  map[string]interface{}{
+//	    "a": map[string]interface{}{
+//			  "b": map[string]interface{}{
+//				  "c": 4,
+//			  },
+//		  },
+//	  }
 func queryToMap(param string) (map[string]interface{}, error) {
 	rawKey, rawValue, err := splitKeyAndValue(param)
 	if err != nil {

util/reflect/struct_test.go

@@ -190,9 +190,9 @@ func TestStructFieldByTag(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if v, ok := iface.(*[]string); !ok {
+	if v, ok := iface.([]string); !ok {
 		t.Fatalf("not *[]string %v", iface)
-	} else if len(*v) != 2 {
+	} else if len(v) != 2 {
 		t.Fatalf("invalid number %v", iface)
 	}
 }