Common: Add utility function that wraps localtime_s() or localtime_t().

Source/Core/Common/CMakeLists.txt

@@ -138,6 +138,8 @@ add_library(common
   Thread.h
   Timer.cpp
   Timer.h
+  TimeUtil.cpp
+  TimeUtil.h
   TraversalClient.cpp
   TraversalClient.h
   TraversalProto.h

Source/Core/Common/TimeUtil.cpp

@@ -0,0 +1,24 @@
+// Copyright 2024 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "Common/TimeUtil.h"
+
+#include <ctime>
+#include <optional>
+
+namespace Common
+{
+std::optional<std::tm> Localtime(std::time_t time)
+{
+  std::tm local_time;
+#ifdef _MSC_VER
+  if (localtime_s(&local_time, &time) != 0)
+    return std::nullopt;
+#else
+  std::tm* result = localtime_r(&time, &local_time);
+  if (result != &local_time)
+    return std::nullopt;
+#endif
+  return local_time;
+}
+}  // Namespace Common

Source/Core/Common/TimeUtil.h

@@ -0,0 +1,13 @@
+// Copyright 2024 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <ctime>
+#include <optional>
+
+namespace Common
+{
+// Threadsafe and error-checking variant of std::localtime()
+std::optional<std::tm> Localtime(std::time_t time);
+}  // Namespace Common

Source/Core/DolphinLib.props

@@ -161,6 +161,7 @@
     <ClInclude Include="Common\SymbolDB.h" />
     <ClInclude Include="Common\Thread.h" />
     <ClInclude Include="Common\Timer.h" />
+    <ClInclude Include="Common\TimeUtil.h" />
     <ClInclude Include="Common\TraversalClient.h" />
     <ClInclude Include="Common\TraversalProto.h" />
     <ClInclude Include="Common\TypeUtils.h" />
@@ -832,6 +833,7 @@
     <ClCompile Include="Common\SymbolDB.cpp" />
     <ClCompile Include="Common\Thread.cpp" />
     <ClCompile Include="Common\Timer.cpp" />
+    <ClCompile Include="Common\TimeUtil.cpp" />
     <ClCompile Include="Common\TraversalClient.cpp" />
     <ClCompile Include="Common\UPnP.cpp" />
     <ClCompile Include="Common\WindowsRegistry.cpp" />