From 296c4e139f5652f7a26f3e179fc2b97223ea695c Mon Sep 17 00:00:00 2001
From: PragmaTwice <twice.mliu@gmail.com>
Date: Sun, 18 Dec 2022 13:14:57 +0800
Subject: [PATCH] Add nodiscard attribute to Status and StatusOr

---
 CMakeLists.txt                |  1 +
 src/common/status.h           |  4 ++--
 utils/kvrocks2redis/writer.cc | 12 +++---------
 3 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 406306a1b26..d4a89c26ee4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -177,6 +177,7 @@ add_library(kvrocks_objs OBJECT ${KVROCKS_SRCS})
 
 target_include_directories(kvrocks_objs PUBLIC src src/common ${PROJECT_BINARY_DIR})
 target_compile_features(kvrocks_objs PUBLIC cxx_std_17)
+# TODO: Add -Werror=unused-result to compile options
 target_compile_options(kvrocks_objs PUBLIC -Wall -Wpedantic -Wsign-compare -Wreturn-type -fno-omit-frame-pointer)
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     target_compile_options(kvrocks_objs PUBLIC -Wno-pedantic)
diff --git a/src/common/status.h b/src/common/status.h
index dcd3d9b9782..5c68f60119c 100644
--- a/src/common/status.h
+++ b/src/common/status.h
@@ -29,7 +29,7 @@
 #include <type_traits>
 #include <utility>
 
-class Status {
+class [[nodiscard]] Status {
  public:
   enum Code : unsigned char {
     cOK = 0,
@@ -121,7 +121,7 @@ template <typename T>
 struct IsStatusOr<StatusOr<T>> : std::integral_constant<bool, true> {};
 
 template <typename T>
-struct StatusOr {  // NOLINT
+struct [[nodiscard]] StatusOr {  // NOLINT
   static_assert(!std::is_same<T, Status>::value, "value_type cannot be Status");
   static_assert(!std::is_same<T, Status::Code>::value, "value_type cannot be Status::Code");
   static_assert(!IsStatusOr<T>::value, "value_type cannot be StatusOr");
diff --git a/utils/kvrocks2redis/writer.cc b/utils/kvrocks2redis/writer.cc
index 44ee4d05da8..423619a0cdb 100644
--- a/utils/kvrocks2redis/writer.cc
+++ b/utils/kvrocks2redis/writer.cc
@@ -34,22 +34,16 @@ Writer::~Writer() {
 }
 
 Status Writer::Write(const std::string &ns, const std::vector<std::string> &aofs) {
-  auto s = GetAofFd(ns);
-  if (!s.IsOK()) {
-    return Status(Status::NotOK, s.Msg());
-  }
+  GET_OR_RET(GetAofFd(ns));
   for (const auto &aof : aofs) {
-    Util::Write(aof_fds_[ns], aof);
+    GET_OR_RET(Util::Write(aof_fds_[ns], aof));
   }
 
   return Status::OK();
 }
 
 Status Writer::FlushDB(const std::string &ns) {
-  auto s = GetAofFd(ns, true);
-  if (!s.IsOK()) {
-    return Status(Status::NotOK, s.Msg());
-  }
+  GET_OR_RET(GetAofFd(ns, true));
 
   return Status::OK();
 }