Misc: Add error checking to LocalTime()

src/common/time_helpers.h

@@ -4,18 +4,22 @@
 #pragma once
 
 #include <ctime>
+#include <optional>
 
 namespace Common {
 
-inline std::tm LocalTime(std::time_t tvalue)
+inline std::optional<std::tm> LocalTime(std::time_t tvalue)
 {
-  std::tm ttime;
+  std::optional<std::tm> ret;
+  ret.emplace();
 #ifdef _MSC_VER
-  localtime_s(&ttime, &tvalue);
+  if (localtime_s(&ret.value(), &tvalue) != 0)
+    ret.reset();
 #else
-  localtime_r(&tvalue, &ttime);
+  if (!localtime_r(&tvalue, &ret.value()))
+    ret.reset();
 #endif
-  return ttime;
+  return ret;
 }
 
 } // namespace Common

src/core/game_list.cpp

@@ -1594,14 +1594,15 @@ std::string GameList::FormatTimestamp(std::time_t timestamp)
   }
   else
   {
-    const std::tm ctime = Common::LocalTime(std::time(nullptr));
-    const std::tm ttime = Common::LocalTime(timestamp);
-    if (ctime.tm_year == ttime.tm_year && ctime.tm_yday == ttime.tm_yday)
+    const std::optional<std::tm> ctime = Common::LocalTime(std::time(nullptr));
+    const std::optional<std::tm> ttime = Common::LocalTime(timestamp);
+    if (ctime.has_value() && ttime.has_value() && ctime->tm_year == ttime->tm_year && ctime->tm_yday == ttime->tm_yday)
     {
       ret = TRANSLATE_STR("GameList", "Today");
     }
-    else if ((ctime.tm_year == ttime.tm_year && ctime.tm_yday == (ttime.tm_yday + 1)) ||
-             (ctime.tm_yday == 0 && (ctime.tm_year - 1) == ttime.tm_year))
+    else if (ctime.has_value() && ttime.has_value() &&
+             ((ctime->tm_year == ttime->tm_year && ctime->tm_yday == (ttime->tm_yday + 1)) ||
+              (ctime->tm_yday == 0 && (ctime->tm_year - 1) == ttime->tm_year)))
     {
       ret = TRANSLATE_STR("GameList", "Yesterday");
     }

src/core/imgui_overlays.cpp

@@ -1158,7 +1158,7 @@ void SaveStateSelectorUI::InitializeListEntry(ListEntry* li, ExtendedSaveStateIn
     li->game_details = fmt::format(TRANSLATE_FS("SaveStateSelectorUI", "{} ({})"), ssi->title, ssi->serial);
 
   li->summary = fmt::format(TRANSLATE_FS("SaveStateSelectorUI", DATE_TIME_FORMAT),
-                            Common::LocalTime(static_cast<std::time_t>(ssi->timestamp)));
+                            Common::LocalTime(static_cast<std::time_t>(ssi->timestamp)).value_or(std::tm{}));
   li->filename = Path::GetFileName(path);
   li->slot = slot;
   li->global = global;
@@ -1458,9 +1458,14 @@ void SaveStateSelectorUI::ShowSlotOSDMessage()
   FILESYSTEM_STAT_DATA sd;
   std::string date;
   if (!path.empty() && FileSystem::StatFile(path.c_str(), &sd))
-    date = fmt::format(TRANSLATE_FS("SaveStateSelectorUI", DATE_TIME_FORMAT), Common::LocalTime(sd.ModificationTime));
+  {
+    date = fmt::format(TRANSLATE_FS("SaveStateSelectorUI", DATE_TIME_FORMAT),
+                       Common::LocalTime(sd.ModificationTime).value_or(std::tm{}));
+  }
   else
+  {
     date = TRANSLATE_STR("SaveStateSelectorUI", "no save yet");
+  }
 
   Host::AddIconOSDMessage(
     "ShowSlotOSDMessage", ICON_EMOJI_MAGNIFIYING_GLASS_TILTED_LEFT,

src/core/system.cpp

@@ -353,7 +353,7 @@ static StateVars s_state;
 
 static TinyString GetTimestampStringForFileName()
 {
-  return TinyString::from_format("{:%Y-%m-%d-%H-%M-%S}", Common::LocalTime(std::time(nullptr)));
+  return TinyString::from_format("{:%Y-%m-%d-%H-%M-%S}", Common::LocalTime(std::time(nullptr)).value_or(std::tm{}));
 }
 
 bool System::PerformEarlyHardwareChecks(Error* error)

src/duckstation-mini/mini_host.cpp

@@ -1416,10 +1416,12 @@ std::string Host::FormatNumber(NumberFormatType type, s64 value)
         DefaultCaseIsUnreachable();
     }
 
-    char buf[128];
-    const std::tm ttime = Common::LocalTime(static_cast<std::time_t>(value));
-    std::strftime(buf, std::size(buf), format, &ttime);
-    ret.assign(buf);
+    ret.resize(128);
+
+    if (const std::optional<std::tm> ltime = Common::LocalTime(static_cast<std::time_t>(value)))
+      ret.resize(std::strftime(ret.data(), ret.size(), format, &ltime.value()));
+    else
+      ret = "Invalid";
   }
   else
   {

src/duckstation-regtest/regtest_host.cpp

@@ -605,10 +605,12 @@ std::string Host::FormatNumber(NumberFormatType type, s64 value)
         DefaultCaseIsUnreachable();
     }
 
-    char buf[128];
-    const std::tm ttime = Common::LocalTime(static_cast<std::time_t>(value));
-    std::strftime(buf, std::size(buf), format, &ttime);
-    ret.assign(buf);
+    ret.resize(128);
+
+    if (const std::optional<std::tm> ltime = Common::LocalTime(static_cast<std::time_t>(value)))
+      ret.resize(std::strftime(ret.data(), ret.size(), format, &ltime.value()));
+    else
+      ret = "Invalid";
   }
   else
   {

src/util/iso_reader.cpp

@@ -573,8 +573,13 @@ std::string IsoReader::ISODirectoryEntryDateTime::GetFormattedTime() const
   const s32 uts_offset = static_cast<s32>(gmt_offset) * 3600;
   const time_t uts = std::mktime(&utime) + uts_offset;
 
-  char buf[128];
-  const std::tm ltime = Common::LocalTime(uts);
-  const size_t len = std::strftime(buf, std::size(buf), "%c", &ltime);
-  return std::string(buf, len);
+  std::string ret;
+  ret.resize(128);
+
+  if (const std::optional<std::tm> ltime = Common::LocalTime(uts))
+    ret.resize(std::strftime(ret.data(), ret.size(), "%c", &ltime.value()));
+  else
+    ret = "Invalid";
+
+  return ret;
 }