HostInterface: Add per-slot save state helper functions

src/core/host_interface.cpp

@@ -361,6 +361,19 @@ bool HostInterface::LoadState(const char* filename)
   return result;
 }
 
+bool HostInterface::LoadState(bool global, u32 slot)
+{
+  const std::string& code = m_system->GetRunningCode();
+  if (!global && code.empty())
+  {
+    ReportFormattedError("Can't save per-game state without a running game code.");
+    return false;
+  }
+
+  std::string save_path = global ? GetGlobalSaveStateFileName(slot) : GetGameSaveStateFileName(code.c_str(), slot);
+  return LoadState(save_path.c_str());
+}
+
 bool HostInterface::SaveState(const char* filename)
 {
   std::unique_ptr<ByteStream> stream =
@@ -384,6 +397,19 @@ bool HostInterface::SaveState(const char* filename)
   return result;
 }
 
+bool HostInterface::SaveState(bool global, u32 slot)
+{
+  const std::string& code = m_system->GetRunningCode();
+  if (!global && code.empty())
+  {
+    ReportFormattedError("Can't save per-game state without a running game code.");
+    return false;
+  }
+
+  std::string save_path = global ? GetGlobalSaveStateFileName(slot) : GetGameSaveStateFileName(code.c_str(), slot);
+  return SaveState(save_path.c_str());
+}
+
 void HostInterface::UpdateSpeedLimiterState()
 {
   m_speed_limiter_enabled = m_settings.speed_limiter_enabled && !m_speed_limiter_temp_disabled;
@@ -543,6 +569,31 @@ std::string HostInterface::GetGameMemoryCardPath(const char* game_code, u32 slot
   return GetUserDirectoryRelativePath("memcards/game_card_%s_%d.mcd", game_code, slot + 1);
 }
 
+std::vector<HostInterface::SaveStateInfo> HostInterface::GetAvailableSaveStates(const char* game_code)
+{
+  std::vector<SaveStateInfo> si;
+  std::string path;
+
+  auto add_path = [&si](std::string path, s32 slot, bool global) {
+    FILESYSTEM_STAT_DATA sd;
+    if (!FileSystem::StatFile(path.c_str(), &sd))
+      return;
+
+    si.push_back(SaveStateInfo{std::move(path), sd.ModificationTime.AsUnixTimestamp(), static_cast<s32>(slot), global});
+  };
+
+  if (game_code && std::strlen(game_code) > 0)
+  {
+    for (s32 i = 1; i <= PER_GAME_SAVE_STATE_SLOTS; i++)
+      add_path(GetGameSaveStateFileName(game_code, i), i, false);
+  }
+
+  for (s32 i = 1; i <= GLOBAL_SAVE_STATE_SLOTS; i++)
+    add_path(GetGlobalSaveStateFileName(i), i, true);
+
+  return si;
+}
+
 void HostInterface::SetDefaultSettings()
 {
   m_settings.region = ConsoleRegion::Auto;

src/core/host_interface.h

@@ -56,8 +56,6 @@ public:
   /// Loads the BIOS image for the specified region.
   virtual std::optional<std::vector<u8>> GetBIOSImage(ConsoleRegion region);
 
-  bool LoadState(const char* filename);
-  bool SaveState(const char* filename);
 
   /// Returns the base user directory path.
   const std::string& GetUserDirectory() const { return m_user_directory; }
@@ -71,7 +69,9 @@ protected:
     AUDIO_SAMPLE_RATE = 44100,
     AUDIO_CHANNELS = 2,
     AUDIO_BUFFER_SIZE = 2048,
-    AUDIO_BUFFERS = 2
+    AUDIO_BUFFERS = 2,
+    PER_GAME_SAVE_STATE_SLOTS = 10,
+    GLOBAL_SAVE_STATE_SLOTS = 10
   };
 
   struct OSDMessage
@@ -81,6 +81,14 @@ protected:
     float duration;
   };
 
+  struct SaveStateInfo
+  {
+    std::string path;
+    u64 timestamp;
+    s32 slot;
+    bool global;
+  };
+
   virtual void SwitchGPURenderer();
   virtual void OnSystemPerformanceCountersUpdated();
   virtual void OnRunningGameChanged();
@@ -111,6 +119,17 @@ protected:
   /// Returns the default path to a memory card for a specific game.
   std::string GetGameMemoryCardPath(const char* game_code, u32 slot);
 
+  /// Returns a list of save states for the specified game code.
+  std::vector<SaveStateInfo> GetAvailableSaveStates(const char* game_code);
+
+  /// Loads the current emulation state from file. Specifying a slot of -1 loads the "resume" game state.
+  bool LoadState(bool global, u32 slot);
+  bool LoadState(const char* filename);
+
+  /// Saves the current emulation state to a file. Specifying a slot of -1 saves the "resume" save state.
+  bool SaveState(bool global, u32 slot);
+  bool SaveState(const char* filename);
+
   /// Restores all settings to defaults.
   void SetDefaultSettings();