Swift Mailer ruins autolading - php

Question

I'm writing simple PHP application which is using Swift Mailer library. My app doesn't use namespaces nor composer.
However, after requiring swift_required.php my (model) classes are not found (Fatal error: Class 'Format' not found is thrown by PHP interpret).
Autolading
define("_DOCUMENT_ROOT", str_replace("//", "/", $_SERVER['DOCUMENT_ROOT'] . "/"));
function __autoload($class_name) {
$file_name = $class_name . '.php';
$include_foleder = array("php/model/", "templates/","cron/crons_tasks/");
foreach ($include_foleder as $folder) {
$abs_path = _DOCUMENT_ROOT . $folder . $file_name;
if (file_exists($abs_path)) {
require_once $abs_path;
}
}
}
Problematic part of function
$bar = Format::bar($foo); //works fine
require_once _DOCUMENT_ROOT . "php/lib/swiftmailer-master/lib/swift_required.php"; //works fine
$bar = Format::bar($foo); //Class not found
Class Format is my custom class, located in _DOCUMENT_ROOT . php/model/Format.php. Also other custom classes (from model folder) after requiring Swift Mailer are not found.
So I guessing that my former autoload is somehow overridden by Swift Mailer, is this possible?
Thank you.

Answer 1

Instead of __autoload(), you should use spl_autoload_register.
If there must be multiple autoload functions, spl_autoload_register()
allows for this. It effectively creates a queue of autoload functions,
and runs through each of them in the order they are defined. By
contrast, __autoload() may only be defined once.
http://php.net/manual/en/function.spl-autoload-register.php
define("_DOCUMENT_ROOT", str_replace("//", "/", $_SERVER['DOCUMENT_ROOT'] . "/"));
spl_autoload_register(function($class_name) {
$file_name = $class_name . '.php';
$include_folder = array("php/model/", "templates/","cron/crons_tasks/");
foreach ($include_folder as $folder) {
$abs_path = _DOCUMENT_ROOT . $folder . $file_name;
if (file_exists($abs_path)) {
require_once $abs_path;
}
}
});