dynamic: add IterateFields

pkg/dynamic/iterate.go

@@ -10,6 +10,44 @@ type StructFieldIterator func(tag string, ft reflect.StructField, fv reflect.Val
 
 var ErrCanNotIterateNilPointer = errors.New("can not iterate struct on a nil pointer")
 
+func IterateFields(obj interface{}, cb func(ft reflect.StructField, fv reflect.Value) error) error {
+	sv := reflect.ValueOf(obj)
+	st := reflect.TypeOf(obj)
+
+	if st.Kind() != reflect.Ptr {
+		return fmt.Errorf("f should be a pointer of a struct, %s given", st)
+	}
+
+	// for pointer, check if it's nil
+	if sv.IsNil() {
+		return ErrCanNotIterateNilPointer
+	}
+
+	// solve the reference
+	st = st.Elem()
+	sv = sv.Elem()
+
+	if st.Kind() != reflect.Struct {
+		return fmt.Errorf("f should be a struct, %s given", st)
+	}
+
+	for i := 0; i < sv.NumField(); i++ {
+		fv := sv.Field(i)
+		ft := st.Field(i)
+
+		// skip unexported fields
+		if !st.Field(i).IsExported() {
+			continue
+		}
+
+		if err := cb(ft, fv) ; err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func IterateFieldsByTag(obj interface{}, tagName string, cb StructFieldIterator) error {
 	sv := reflect.ValueOf(obj)
 	st := reflect.TypeOf(obj)

pkg/dynamic/iterate_test.go

@@ -0,0 +1,25 @@
+package dynamic
+
+import (
+	"os"
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIterateFields(t *testing.T) {
+	var a = struct {
+		A int
+		B float64
+		C *os.File
+	}{}
+
+	cnt := 0
+	err := IterateFields(&a, func(ft reflect.StructField, fv reflect.Value) error {
+		cnt++
+		return nil
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, 3, cnt)
+}