Method FiosNumberedSaveName

src/fios.cpp:701–732

* Constructs FiosNumberedSaveName. Initial number is the most recent save, or -1 if not found. * @param prefix The prefix to use to generate a filename. */

 * @param prefix The prefix to use to generate a filename.
 */
FiosNumberedSaveName::FiosNumberedSaveName(const std::string &prefix) : prefix(prefix), number(-1)
{
	static std::optional<std::string> _autosave_path;
	if (!_autosave_path) _autosave_path = FioFindDirectory(AUTOSAVE_DIR);

	static std::string _prefix; ///< Static as the lambda needs access to it.

	/* Callback for FiosFileScanner. */
	static FiosGetTypeAndNameProc *const proc = [](SaveLoadOperation, std::string_view file, std::string_view ext) {
		if (StrEqualsIgnoreCase(ext, ".sav") && file.starts_with(_prefix)) return std::tuple(FIOS_TYPE_FILE, std::string{});
		return std::tuple(FIOS_TYPE_INVALID, std::string{});
	};

	/* Prefix to check in the callback. */
	_prefix = *_autosave_path + this->prefix;

	/* Get the save list. */
	FileList list;
	FiosFileScanner scanner(SLO_SAVE, proc, list);
	scanner.Scan(".sav", *_autosave_path, false);

	/* Find the number for the most recent save, if any. */
	if (list.begin() != list.end()) {
		SortingBits order = _savegame_sort_order;
		_savegame_sort_order = SORT_BY_DATE | SORT_DESCENDING;
		std::sort(list.begin(), list.end());
		_savegame_sort_order = order;

		std::string name = list.begin()->title.GetDecodedString();
		std::from_chars(name.data() + this->prefix.size(), name.data() + name.size(), this->number);
	}
}

/**
 * Generate a savegame name and number according to _settings_client.gui.max_num_autosaves.