support empty struct

Author: Tao Wen

gen/main.go

@@ -204,10 +204,12 @@ func genMap(mapType *ast.MapType) {
 }
 
 func genStruct(structType *ast.StructType) {
+	oldLines := lines
 	_l("  more := iter.ReadObjectHead()")
 	_l("  for more {")
 	_l("    field := iter.ReadObjectField()")
 	_l("    switch {")
+	isEmptyStruct := true
 	for _, field := range structType.Fields.List {
 		fieldName := field.Names[0].Name
 		encodedFieldName := fieldName
@@ -230,10 +232,15 @@ func genStruct(structType *ast.StructType) {
 		if isNotExported {
 			continue
 		}
+		isEmptyStruct = false
 		ptr := fmt.Sprintf("&(*out).%s", fieldName)
 		_f("    case field == `%s`:", encodedFieldName)
 		genDecodeStmt(field.Type, ptr)
 	}
+	if isEmptyStruct {
+		lines = oldLines
+		return
+	}
 	_l("    default:")
 	_l("      iter.Skip()")
 	_l("    }")

value_tests/EmptyStruct.go

@@ -0,0 +1,5 @@
+package value_tests
+
+//go:generate go run github.com/json-iterator/tinygo/gen
+type EmptyStruct struct {
+}

value_tests/EmptyStruct_json.go

@@ -0,0 +1,15 @@
+package value_tests
+
+import jsoniter "github.com/json-iterator/tinygo"
+
+func EmptyStruct_json_unmarshal(iter *jsoniter.Iterator, out *EmptyStruct) {
+}
+type EmptyStruct_json struct {
+}
+func (json EmptyStruct_json) Type() interface{} {
+  var val EmptyStruct
+  return &val
+}
+func (json EmptyStruct_json) Unmarshal(iter *jsoniter.Iterator, val interface{}) {
+  EmptyStruct_json_unmarshal(iter, val.(*EmptyStruct))
+}