#197 fix place holder encoder to use EncodeInterface, WriteToStream is unsafe when the real encoder is unknown

Author: taowen

feature_reflect.go

@@ -164,7 +164,7 @@ func (encoder *placeholderEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
 }
 
 func (encoder *placeholderEncoder) EncodeInterface(val interface{}, stream *Stream) {
-	WriteToStream(val, stream, encoder)
+	encoder.getRealEncoder().EncodeInterface(val, stream)
 }
 
 func (encoder *placeholderEncoder) IsEmpty(ptr unsafe.Pointer) bool {

jsoniter_interface_test.go

@@ -7,8 +7,23 @@ import (
 	"unsafe"
 
 	"github.com/stretchr/testify/require"
+	"reflect"
 )
 
+func Test_write_empty_interface_via_placeholder(t *testing.T) {
+	should := require.New(t)
+	m := map[uint32]interface{}{1:"hello"}
+	inf := reflect.ValueOf(m).MapIndex(reflect.ValueOf(uint32(1))).Interface()
+	encoder := &placeholderEncoder{
+		cfg: ConfigFastest.(*frozenConfig),
+		cacheKey: reflect.TypeOf(m).Elem(),
+	}
+	stream := ConfigFastest.BorrowStream(nil)
+	encoderOfType(ConfigFastest.(*frozenConfig), reflect.TypeOf(m).Elem())
+	encoder.EncodeInterface(inf, stream)
+	should.Equal(`"hello"`, string(stream.Buffer()))
+}
+
 func Test_write_array_of_interface(t *testing.T) {
 	should := require.New(t)
 	array := []interface{}{"hello"}