System: Support loading m3u playlists

src/core/cdrom.h

@@ -30,7 +30,7 @@ public:
   bool DoState(StateWrapper& sw);
 
   bool HasMedia() const { return m_reader.HasMedia(); }
-  std::string GetMediaFileName() const { return m_reader.GetMediaFileName(); }
+  const std::string& GetMediaFileName() const { return m_reader.GetMediaFileName(); }
 
   void InsertMedia(std::unique_ptr<CDImage> media);
   std::unique_ptr<CDImage> RemoveMedia(bool force = false);

src/core/cdrom_async_reader.h

@@ -19,7 +19,7 @@ public:
   const CDImage::SubChannelQ& GetSectorSubQ() const { return m_subq; }
   const bool HasMedia() const { return static_cast<bool>(m_media); }
   const CDImage* GetMedia() const { return m_media.get(); }
-  const std::string GetMediaFileName() const { return m_media ? m_media->GetFileName() : std::string(); }
+  const std::string& GetMediaFileName() const { return m_media->GetFileName(); }
 
   bool IsUsingThread() const { return m_read_thread.joinable(); }
   void StartThread();

src/core/game_list.cpp

@@ -12,6 +12,7 @@
 #include <algorithm>
 #include <array>
 #include <cctype>
+#include <fstream>
 #include <string_view>
 #include <tinyxml2.h>
 #include <utility>
@@ -214,6 +215,58 @@ bool GameList::IsPsfFileName(const char* path)
   return (extension && StringUtil::Strcasecmp(extension, ".psf") == 0);
 }
 
+bool GameList::IsM3UFileName(const char* path)
+{
+  const char* extension = std::strrchr(path, '.');
+  return (extension && StringUtil::Strcasecmp(extension, ".m3u") == 0);
+}
+
+std::vector<std::string> GameList::ParseM3UFile(const char* path)
+{
+  std::ifstream ifs(path);
+  if (!ifs.is_open())
+  {
+    Log_ErrorPrintf("Failed to open %s", path);
+    return {};
+  }
+
+  std::vector<std::string> entries;
+  std::string line;
+  while (std::getline(ifs, line))
+  {
+    u32 start_offset = 0;
+    while (start_offset < line.size() && std::isspace(line[start_offset]))
+      start_offset++;
+
+    // skip comments
+    if (start_offset == line.size() || line[start_offset] == '#')
+      continue;
+
+    // strip ending whitespace
+    u32 end_offset = static_cast<u32>(line.size()) - 1;
+    while (std::isspace(line[end_offset]) && end_offset > start_offset)
+      end_offset--;
+
+    // anything?
+    if (start_offset == end_offset)
+      continue;
+
+    std::string entry_path(line.begin() + start_offset, line.begin() + end_offset + 1);
+    if (!FileSystem::IsAbsolutePath(entry_path))
+    {
+      SmallString absolute_path;
+      FileSystem::BuildPathRelativeToFile(absolute_path, path, entry_path.c_str());
+      entry_path = absolute_path;
+    }
+
+    Log_DevPrintf("Read path from m3u: '%s'", entry_path.c_str());
+    entries.push_back(std::move(entry_path));
+  }
+
+  Log_InfoPrintf("Loaded %zu paths from m3u '%s'", entries.size(), path);
+  return entries;
+}
+
 const char* GameList::GetGameListCompatibilityRatingString(GameListCompatibilityRating rating)
 {
   static constexpr std::array<const char*, static_cast<size_t>(GameListCompatibilityRating::Count)> names = {

src/core/game_list.h

@@ -77,6 +77,12 @@ public:
   /// Returns true if the filename is a Portable Sound Format file we can uncompress/load.
   static bool IsPsfFileName(const char* path);
 
+  /// Returns true if the filename is a M3U Playlist we can handle.
+  static bool IsM3UFileName(const char* path);
+
+  /// Parses an M3U playlist, returning the entries.
+  static std::vector<std::string> ParseM3UFile(const char* path);
+
   /// Returns a string representation of a compatibility level.
   static const char* GetGameListCompatibilityRatingString(GameListCompatibilityRating rating);
 

src/core/system.cpp

@@ -26,6 +26,7 @@
 #include "timers.h"
 #include <cstdio>
 #include <imgui.h>
+#include <limits>
 Log_SetChannel(System);
 
 #ifdef WIN32
@@ -175,8 +176,35 @@ bool System::Boot(const SystemBootParameters& params)
     }
     else
     {
-      Log_InfoPrintf("Loading CD image '%s'...", params.filename.c_str());
-      media = OpenCDImage(params.filename.c_str(), params.override_load_image_to_ram.value_or(false));
+      u32 playlist_index;
+      if (GameList::IsM3UFileName(params.filename.c_str()))
+      {
+        m_media_playlist = GameList::ParseM3UFile(params.filename.c_str());
+        if (m_media_playlist.empty())
+        {
+          m_host_interface->ReportFormattedError("Failed to parse playlist '%s'", params.filename.c_str());
+          return false;
+        }
+
+        if (params.media_playlist_index >= m_media_playlist.size())
+        {
+          Log_WarningPrintf("Media playlist index %u out of range, using first", params.media_playlist_index);
+          playlist_index = 0;
+        }
+        else
+        {
+          playlist_index = params.media_playlist_index;
+        }
+      }
+      else
+      {
+        AddMediaPathToPlaylist(params.filename);
+        playlist_index = 0;
+      }
+
+      const std::string& media_path = m_media_playlist[playlist_index];
+      Log_InfoPrintf("Loading CD image '%s' from playlist index %u...", media_path.c_str(), playlist_index);
+      media = OpenCDImage(media_path.c_str(), params.load_image_to_ram);
       if (!media)
       {
         m_host_interface->ReportFormattedError("Failed to load CD image '%s'", params.filename.c_str());
@@ -518,11 +546,14 @@ bool System::SaveState(ByteStream* state, u32 screenshot_size /* = 128 */)
   StringUtil::Strlcpy(header.title, m_running_game_title.c_str(), sizeof(header.title));
   StringUtil::Strlcpy(header.game_code, m_running_game_code.c_str(), sizeof(header.game_code));
 
-  std::string media_filename = m_cdrom->GetMediaFileName();
+  if (m_cdrom->HasMedia())
+  {
+    const std::string& media_filename = m_cdrom->GetMediaFileName();
     header.offset_to_media_filename = static_cast<u32>(state->GetPosition());
     header.media_filename_length = static_cast<u32>(media_filename.length());
     if (!media_filename.empty() && !state->Write2(media_filename.data(), header.media_filename_length))
       return false;
+  }
 
   // save screenshot
   if (screenshot_size > 0)
@@ -971,6 +1002,8 @@ bool System::InsertMedia(const char* path)
 
   UpdateRunningGame(path, image.get());
   m_cdrom->InsertMedia(std::move(image));
+  Log_InfoPrintf("Inserted media from %s (%s, %s)", m_running_game_path.c_str(), m_running_game_code.c_str(),
+                 m_running_game_title.c_str());
 
   if (GetSettings().HasAnyPerGameMemoryCards())
   {
@@ -1196,3 +1229,89 @@ void System::UpdateRunningGame(const char* path, CDImage* image)
 
   m_host_interface->OnRunningGameChanged();
 }
+
+u32 System::GetMediaPlaylistIndex() const
+{
+  if (!m_cdrom->HasMedia())
+    return std::numeric_limits<u32>::max();
+
+  const std::string& media_path = m_cdrom->GetMediaFileName();
+  for (u32 i = 0; i < static_cast<u32>(m_media_playlist.size()); i++)
+  {
+    if (m_media_playlist[i] == media_path)
+      return i;
+  }
+
+  return std::numeric_limits<u32>::max();
+}
+
+bool System::AddMediaPathToPlaylist(const std::string_view& path)
+{
+  if (std::any_of(m_media_playlist.begin(), m_media_playlist.end(),
+                  [&path](const std::string& p) { return (path == p); }))
+  {
+    return false;
+  }
+
+  m_media_playlist.emplace_back(path);
+  return true;
+}
+
+bool System::RemoveMediaPathFromPlaylist(const std::string_view& path)
+{
+  for (u32 i = 0; i < static_cast<u32>(m_media_playlist.size()); i++)
+  {
+    if (path == m_media_playlist[i])
+      return RemoveMediaPathFromPlaylist(i);
+  }
+
+  return false;
+}
+
+bool System::RemoveMediaPathFromPlaylist(u32 index)
+{
+  if (index >= static_cast<u32>(m_media_playlist.size()))
+    return false;
+
+  if (GetMediaPlaylistIndex() == index)
+  {
+    m_host_interface->ReportMessage("Removing current media from playlist, removing media from CD-ROM.");
+    m_cdrom->RemoveMedia();
+  }
+
+  m_media_playlist.erase(m_media_playlist.begin() + index);
+  return true;
+}
+
+bool System::ReplaceMediaPathFromPlaylist(u32 index, const std::string_view& path)
+{
+  if (index >= static_cast<u32>(m_media_playlist.size()))
+    return false;
+
+  if (GetMediaPlaylistIndex() == index)
+  {
+    m_host_interface->ReportMessage("Changing current media from playlist, replacing current media.");
+    m_cdrom->RemoveMedia();
+
+    m_media_playlist[index] = path;
+    InsertMedia(m_media_playlist[index].c_str());
+  }
+  else
+  {
+    m_media_playlist[index] = path;
+  }
+
+  return true;
+}
+
+bool System::SwitchMediaFromPlaylist(u32 index)
+{
+  if (index >= m_media_playlist.size())
+    return false;
+
+  const std::string& path = m_media_playlist[index];
+  if (m_cdrom->HasMedia() && m_cdrom->GetMediaFileName() == path)
+    return true;
+
+  return InsertMedia(path.c_str());
+}

src/core/system.h

@@ -38,8 +38,9 @@ struct SystemBootParameters
   std::string filename;
   std::optional<bool> override_fast_boot;
   std::optional<bool> override_fullscreen;
-  std::optional<bool> override_load_image_to_ram;
   std::unique_ptr<ByteStream> state_stream;
+  u32 media_playlist_index = 0;
+  bool load_image_to_ram = false;
   bool force_software_renderer = false;
 };
 
@@ -152,6 +153,28 @@ public:
   std::unique_ptr<TimingEvent> CreateTimingEvent(std::string name, TickCount period, TickCount interval,
                                                  TimingEventCallback callback, bool activate);
 
+  /// Returns the number of entries in the media/disc playlist.
+  ALWAYS_INLINE u32 GetMediaPlaylistCount() const { return static_cast<u32>(m_media_playlist.size()); }
+
+  /// Returns the current image from the media/disc playlist.
+  u32 GetMediaPlaylistIndex() const;
+
+  /// Returns the path to the specified playlist index.
+  const std::string& GetMediaPlaylistPath(u32 index) const { return m_media_playlist[index]; }
+
+  /// Adds a new path to the media playlist.
+  bool AddMediaPathToPlaylist(const std::string_view& path);
+
+  /// Removes a path from the media playlist.
+  bool RemoveMediaPathFromPlaylist(const std::string_view& path);
+  bool RemoveMediaPathFromPlaylist(u32 index);
+
+  /// Changes a path from the media playlist.
+  bool ReplaceMediaPathFromPlaylist(u32 index, const std::string_view& path);
+
+  /// Switches to the specified media/disc playlist index.
+  bool SwitchMediaFromPlaylist(u32 index);
+
 private:
   System(HostInterface* host_interface);
 
@@ -241,4 +264,7 @@ private:
   u32 m_last_global_tick_counter = 0;
   Common::Timer m_fps_timer;
   Common::Timer m_frame_timer;
+
+  // Playlist of disc images.
+  std::vector<std::string> m_media_playlist;
 };