fix: 修复500 panic和NaN问题

- 修复HashInfo nil pointer导致的500 panic (fsread.go)
- 修复StorageDetails为nil导致的NaN显示 (storage.go, op/storage.go)
- 添加DiskUsage.MarshalJSON()确保返回used_space字段

Author: cyk

internal/model/storage.go

@@ -1,6 +1,7 @@
 package model
 
 import (
+	"encoding/json"
 	"time"
 )
 
@@ -62,6 +63,21 @@ type DiskUsage struct {
 	FreeSpace  uint64 `json:"free_space"`
 }
 
+func (d DiskUsage) UsedSpace() uint64 {
+	if d.TotalSpace > d.FreeSpace {
+		return d.TotalSpace - d.FreeSpace
+	}
+	return 0
+}
+
+func (d DiskUsage) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]interface{}{
+		"total_space": d.TotalSpace,
+		"free_space":  d.FreeSpace,
+		"used_space":  d.UsedSpace(),
+	})
+}
+
 type StorageDetails struct {
 	DiskUsage
 }

internal/op/storage.go

@@ -355,7 +355,7 @@ func GetStorageVirtualFilesWithDetailsByPath(ctx context.Context, prefix string,
 		ret := &model.ObjStorageDetails{
 			Obj: obj,
 			StorageDetailsWithName: model.StorageDetailsWithName{
-				StorageDetails: nil,
+				StorageDetails: &model.StorageDetails{}, // 初始化为空结构体而不是nil
 				DriverName:     d.Config().Name,
 			},
 		}
@@ -371,7 +371,9 @@ func GetStorageVirtualFilesWithDetailsByPath(ctx context.Context, prefix string,
 		}(d)
 		select {
 		case r := <-resultChan:
-			ret.StorageDetails = r
+			if r != nil {
+				ret.StorageDetails = r
+			}
 		case <-time.After(time.Second):
 		}
 		return ret

server/handles/fsread.go

@@ -231,14 +231,18 @@ func toObjsResp(objs []model.Obj, parent string, encrypt bool) []ObjResp {
 	for _, obj := range objs {
 		thumb, _ := model.GetThumb(obj)
 		mountDetails, _ := model.GetStorageDetails(obj)
+		hashInfo := obj.GetHash().Export()
+		if hashInfo == nil {
+			hashInfo = make(map[*utils.HashType]string)
+		}
 		resp = append(resp, ObjResp{
 			Name:         obj.GetName(),
 			Size:         obj.GetSize(),
 			IsDir:        obj.IsDir(),
 			Modified:     obj.ModTime(),
 			Created:      obj.CreateTime(),
 			HashInfoStr:  obj.GetHash().String(),
-			HashInfo:     obj.GetHash().Export(),
+			HashInfo:     hashInfo,
 			Sign:         common.Sign(obj, parent, encrypt),
 			Thumb:        thumb,
 			Type:         utils.GetObjType(obj.GetName(), obj.IsDir()),