add m3u support

libretro/main.cpp

@@ -13,6 +13,8 @@
 #include <libretro.h>
 #include <string>
 #include <thread>
+#include <fstream>
+#include <filesystem>
 
 #include "options.h"
 
@@ -358,11 +360,60 @@ void retro_get_system_info(retro_system_info* info)
 #endif
 
 	info->library_name = "pcsx2";
-	info->valid_extensions = "elf|iso|ciso|cue|bin|gz";
+	info->valid_extensions = "elf|iso|ciso|cue|bin|gz|m3u";
 	info->need_fullpath = true;
 	info->block_extract = true;
 }
 
+
+static std::vector<std::string>
+	read_m3u_file(const std::string& m3u_file)
+{
+	log_cb(RETRO_LOG_DEBUG, "Reading M3U file\n");
+	std::vector<std::string>  result;
+	std::ifstream m3u_data{std::filesystem::path(m3u_file)};
+	if (!m3u_data.is_open())
+	{
+		log_cb(RETRO_LOG_ERROR, "M3U file \"%s\" cannot be read\n", m3u_file.c_str());
+		return result;
+	}
+	const std::string m3u_parent = Path::Canonicalize(Path::GetDirectory(m3u_file));
+	// This is the UTF-8 representation of U+FEFF.
+	const std::string utf8_bom = "\xEF\xBB\xBF";
+	std::string line;
+	getline(m3u_data, line);
+	if (line.rfind(utf8_bom,0) == 0)
+	{
+		log_cb(RETRO_LOG_WARN, "M3U file \"%s\" contains UTF-8 BOM\n", m3u_file.c_str());
+		line.erase(0, utf8_bom.length());
+	}
+	for (line; !m3u_data.eof(); getline(m3u_data, line))
+	{
+		if (!line.find('#') == 0) // Comments start with #
+		{
+			std::string m3u_path = line;
+			if (!Path::IsAbsolute(line) && !m3u_parent.empty())
+			{
+				m3u_path = Path::Combine(m3u_parent, line);
+			}
+			std::ifstream discFile(m3u_path);
+			if (discFile.is_open())
+			{
+				log_cb(RETRO_LOG_DEBUG, "Found disc image in M3U file, %s\n", m3u_path.c_str());
+				result.push_back(m3u_path);
+			}
+			else
+			{
+				log_cb(RETRO_LOG_WARN, "File specified in the M3U file \"%s\" was not found\n", m3u_path.c_str());
+			}
+		}
+	}
+	if (result.empty())
+		log_cb(RETRO_LOG_ERROR, "No paths found in the M3U file \"%s\"\n", m3u_file.c_str());
+
+	return result;
+}
+
 void retro_get_system_av_info(retro_system_av_info* info)
 {
 	if (Options::renderer == "Software" || Options::renderer == "Null")
@@ -718,8 +769,18 @@ bool retro_load_game(const struct retro_game_info* game)
 	VMBootParameters boot_params;
 	if(game && game->path)
 	{
-		disk_images.push_back(game->path);
-		boot_params.filename = game->path;
+		std::vector<std::string> game_paths;
+		if (Path::GetExtension(game->path) == "m3u")
+		{
+			game_paths = read_m3u_file(game->path);
+			log_cb(RETRO_LOG_DEBUG, "Found %u game images in M3U file.", game_paths.size());
+		}
+		else
+		{
+			game_paths.push_back(game->path);
+		}
+		disk_images.assign(game_paths.begin(), game_paths.end());
+		boot_params.filename = disk_images[0];
 	}
 
 	cpu_thread = std::thread(cpu_thread_entry, boot_params);