How to use bitsets

To efficiently handle boolean flags, bit sets can be used since TYPO3 v10.

Class \TYPO3\CMS\Core\Type\BitSet provides a TYPO3 implementation of a BitSet. It can be used standalone and accessed from the outside, but we recommend creating specific BitSet classes that extend the TYPO3 BitSet class.

The functionality is best described by an example:

EXT:my_extension/Classes/Utility/SomeClass.php

<?php
declare(strict_types = 1);

define('PERMISSIONS_NONE', 0b0); // 0
define('PERMISSIONS_PAGE_SHOW', 0b1); // 1
define('PERMISSIONS_PAGE_EDIT', 0b10); // 2
define('PERMISSIONS_PAGE_DELETE', 0b100); // 4
define('PERMISSIONS_PAGE_NEW', 0b1000); // 8
define('PERMISSIONS_CONTENT_EDIT', 0b10000); // 16
define('PERMISSIONS_ALL', 0b11111); // 31

$bitSet = new \TYPO3\CMS\Core\Type\BitSet(PERMISSIONS_PAGE_SHOW | PERMISSIONS_PAGE_NEW);
$bitSet->get(PERMISSIONS_PAGE_SHOW); // true
$bitSet->get(PERMISSIONS_CONTENT_EDIT); // false

This is directly using the TYPO3 Core class. Implementing that via an extending class makes it clearer and easier to use:

EXT:my_extension/Classes/Utility/Permissions.php

<?php
declare(strict_types = 1);

class Permissions extends \TYPO3\CMS\Core\Type\BitSet
{
    public const NONE = 0b0; // 0
    public const PAGE_SHOW = 0b1; // 1
    public const PAGE_EDIT = 0b10; // 2
    public const PAGE_DELETE = 0b100; // 4
    public const PAGE_NEW = 0b1000; // 8
    public const CONTENT_EDIT = 0b10000; // 16
    public const ALL = 0b11111; // 31

    /**
     * @param int $permission
     * @return bool
     */
    public function hasPermission(int $permission): bool
    {
        return $this->get($permission);
    }

    /**
     * @return bool
     */
    public function hasAllPermissions(): bool
    {
        return $this->get(static::ALL);
    }

    /**
     * @param int $permission
     */
    public function allow(int $permission): void
    {
        $this->set($permission);
    }
}

EXT:my_extension/Classes/Utility/SomeClass.php

$permissions = new Permissions(Permissions::PAGE_SHOW | Permissions::PAGE_NEW);
$permissions->hasPermission(Permissions::PAGE_SHOW); // true
$permissions->hasPermission(Permissions::CONTENT_EDIT); // false