refactor: use map struct wrappers for and ext, fileHistory, and add serialization methods for them

metadata/file_reference.go

@@ -1,22 +1,34 @@
 package metadata
 
-import "github.com/vmihailenco/msgpack/v5"
+import (
+	"github.com/emirpasic/gods/maps/linkedhashmap"
+	"github.com/vmihailenco/msgpack/v5"
+)
 
 var _ SerializableMetadata = (*FileReference)(nil)
+var _ SerializableMetadata = (*fileHistoryMap)(nil)
+var _ SerializableMetadata = (*extMap)(nil)
+
+type fileHistoryMap struct {
+	linkedhashmap.Map
+}
+type extMap struct {
+	linkedhashmap.Map
+}
 
 type FileReference struct {
 	Name     string         `json:"name"`
 	Created  int            `json:"created"`
 	Version  int            `json:"version"`
 	File     *FileVersion   `json:"file"`
-	Ext      map[string]interface{} `json:"ext"`
+	Ext      extMap         `json:"ext"`
-	History  map[int]*FileVersion   `json:"history"`
+	History  fileHistoryMap `json:"history"`
 	MimeType string         `json:"mimeType"`
 	URI      string         `json:"uri"`
 	Key      string         `json:"key"`
 }
 
-func NewFileReference(name string, created, version int, file *FileVersion, ext map[string]interface{}, history map[int]*FileVersion, mimeType string) *FileReference {
+func NewFileReference(name string, created, version int, file *FileVersion, ext extMap, history fileHistoryMap, mimeType string) *FileReference {
 	return &FileReference{
 		Name:     name,
 		Created:  created,
@@ -130,3 +142,32 @@ func (fr *FileReference) DecodeMsgpack(dec *msgpack.Decoder) error {
 	}
 	return nil
 }
+
+func (ext extMap) EncodeMsgpack(enc *msgpack.Encoder) error {
+	return marshallMapMsgpack(enc, &ext.Map)
+}
+func (ext *extMap) DecodeMsgpack(dec *msgpack.Decoder) error {
+	return unmarshalMapMsgpack(dec, &ext.Map, &extMap{}, true)
+}
+func (fhm fileHistoryMap) EncodeMsgpack(enc *msgpack.Encoder) error {
+	return marshallMapMsgpack(enc, &fhm.Map)
+}
+func (fhm *fileHistoryMap) DecodeMsgpack(dec *msgpack.Decoder) error {
+	return unmarshalMapMsgpack(dec, &fhm.Map, &extMap{}, false)
+}
+
+func (m *fileHistoryMap) UnmarshalJSON(bytes []byte) error {
+	if string(bytes) == "null" {
+		m.Map = *linkedhashmap.New()
+		return nil
+	}
+	return m.FromJSON(bytes)
+}
+
+func (m *extMap) UnmarshalJSON(bytes []byte) error {
+	if string(bytes) == "null" {
+		m.Map = *linkedhashmap.New()
+		return nil
+	}
+	return m.FromJSON(bytes)
+}