一时看不明白大神的想法

现在在维护以前的代码，遇到一个权限的代码

     /// <summary>
        /// 权限校验
        /// </summary>
        /// <param name="Action">权限Action</param>
        /// <returns>true:有权限   false:无权限</returns>
        public static bool CheckIsPermission(string Action)
        {
            Action = Action.ToLower();
            if (string.IsNullOrEmpty(Action)) return false;
            bool flag = true;
            Sanzhang.Entity.RoleInfo roleInfo = GetLoginRoleInfo();
            if (roleInfo != null)
            {
                if ((roleInfo.rRank == 0) || (0 != 0))
                {
                    return flag;
                }
                Action = ",m#" + Action + "#,";
                string permission = roleInfo.rPermission.ToLower();
                //permission = "|" + permission + "|";  袁连杰修改
                permission = "," + permission + ",";
                flag = ((permission.IndexOf(Action) >= 0) && flag);
            }
            return flag;
        }

里面的0!=0是为了干嘛的？

还有下面的

flag = ((permission.IndexOf(Action) >= 0) && flag);
flag中间没有改变过都是true那&&true不还是返回前面表达式的值吗
请各位看官指点一二