Function log_logger_stdout

src/base/log.cpp:385–456

#endif

std::unique_ptr<ILogger> log_logger_stdout()
{
#if !defined(CONF_FAMILY_WINDOWS)
	// TODO: Only enable true color when COLORTERM contains "truecolor".
	// https://github.com/termstandard/colors/tree/65bf0cd1ece7c15fa33a17c17528b02c99f1ae0b#checking-for-colorterm
	const bool Colors = getenv("NO_COLOR") == nullptr && isatty(STDOUT_FILENO);
	return std::make_unique<CLoggerAsync>(io_stdout(), Colors, false);
#else
	// If we currently have no stdout (console, file, pipe),
	// try to attach to the console of the parent process.
	if(GetFileType(GetStdHandle(STD_OUTPUT_HANDLE)) == FILE_TYPE_UNKNOWN)
	{
		AttachConsole(ATTACH_PARENT_PROCESS);
	}

	HANDLE pOutput = GetStdHandle(STD_OUTPUT_HANDLE);
	if(pOutput == nullptr)
	{
		// There is no console, file or pipe that we can output to.
		return nullptr;
	}
	dbg_assert(pOutput != INVALID_HANDLE_VALUE, "GetStdHandle failure");

	const DWORD OutputType = GetFileType(pOutput);
	if(OutputType == FILE_TYPE_CHAR)
	{
		DWORD OldConsoleMode = 0;
		if(!GetConsoleMode(pOutput, &OldConsoleMode))
		{
			// GetConsoleMode can fail with ERROR_INVALID_HANDLE when redirecting output to "nul",
			// which is considered a character file but cannot be used as a console.
			dbg_assert(GetLastError() == ERROR_INVALID_HANDLE, "GetConsoleMode failure");
			return nullptr;
		}

		const bool Colors = _wgetenv(L"NO_COLOR") == nullptr;

		// Try to enable virtual terminal processing in the Windows console.
		// See https://learn.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences
		if(!SetConsoleMode(pOutput, OldConsoleMode | ENABLE_VIRTUAL_TERMINAL_PROCESSING | DISABLE_NEWLINE_AUTO_RETURN))
		{
			// Try to downgrade mode gracefully when failing to set both.
			if(!SetConsoleMode(pOutput, OldConsoleMode | ENABLE_VIRTUAL_TERMINAL_PROCESSING))
			{
				// Fallback to old, slower Windows logging API, when failing to enable virtual terminal processing.
				return std::make_unique<CWindowsConsoleLogger>(pOutput, Colors);
			}
		}

		// Virtual terminal processing was enabled successfully. We can
		// use the async logger with ANSI escape codes for colors now.
		// We need to set the output encoding to UTF-8 manually and
		// convert the HANDLE to an IOHANDLE to use the async logger.
		// We assume UTF-8 is available when virtual terminal processing is.
		dbg_assert(SetConsoleOutputCP(CP_UTF8) != 0, "SetConsoleOutputCP failure");
		return std::make_unique<CLoggerAsync>(ConvertWindowsHandle(pOutput, _O_TEXT), Colors, false);
	}
	else if(OutputType == FILE_TYPE_DISK || OutputType == FILE_TYPE_PIPE)