Add system setting table with cache and also add cache supports for user setting (#18058)

modules/system/user_setting.go

@@ -0,0 +1,34 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package system
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/cache"
+)
+
+func genUserKey(userID int64, key string) string {
+	return fmt.Sprintf("user_%d.setting.%s", userID, key)
+}
+
+// GetUserSetting returns the user setting value via the key
+func GetUserSetting(userID int64, key string) (string, error) {
+	return cache.GetString(genUserKey(userID, key), func() (string, error) {
+		res, err := user.GetSetting(userID, key)
+		if err != nil {
+			return "", err
+		}
+		return res.SettingValue, nil
+	})
+}
+
+// SetUserSetting sets the user setting value
+func SetUserSetting(userID int64, key, value string) error {
+	cache.Remove(genUserKey(userID, key))
+
+	return user.SetUserSetting(userID, key, value)
+}