修复可能导致死锁冲突的Bug

internal/caches/list_file.go

@@ -281,19 +281,18 @@ func (this *FileList) Purge(count int, callback func(hash string) error) error {
 	if err != nil {
 		return err
 	}
-	defer func() {
-		_ = rows.Close()
-	}()
 
 	hashStrings := []string{}
 	for rows.Next() {
 		var hash string
 		err = rows.Scan(&hash)
 		if err != nil {
+			_ = rows.Close()
 			return err
 		}
 		hashStrings = append(hashStrings, hash)
 	}
+	_ = rows.Close() // 不能使用defer，防止读写冲突
 
 	// 不在 rows.Next() 循环中操作是为了避免死锁
 	for _, hash := range hashStrings {

internal/caches/list_file_test.go

@@ -236,6 +236,27 @@ func TestFileList_CleanAll(t *testing.T) {
 	t.Log(list.Count())
 }
 
+func TestFileList_Conflict(t *testing.T) {
+	list := NewFileList(Tea.Root + "/data").(*FileList)
+	err := list.Init()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rows, err := list.purgeStmt.Query(time.Now().Unix(), 1000)
+	if err != nil {
+		t.Fatal(err)
+	}
+	go func() {
+		time.Sleep(5 * time.Second)
+		_ = rows.Close()
+	}()
+
+	t.Log("before exists")
+	t.Log(list.Exist("123456"))
+	t.Log("after exists")
+}
+
 func BenchmarkFileList_Exist(b *testing.B) {
 	list := NewFileList(Tea.Root + "/data")
 	err := list.Init()