FailsafeContainer.php

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<?php
 
declare(strict_types=1);
 
/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
 
namespace ‪TYPO3\CMS\Core\DependencyInjection;
 
use Psr\Container\ContainerInterface;
 
class ‪FailsafeContainer implements ContainerInterface
{
    private ‪$entries = [];
 
    private ‪$factories = [];
 
    public function ‪__construct(iterable $providers = [], array ‪$entries = [])
    {
        $this->entries = ‪$entries;
 
        ‪$factories = [];
        foreach ($providers as $provider) {
            ‪$factories = $provider->getFactories() + ‪$factories;
            foreach ($provider->getExtensions() as $id => $extension) {
                // Decorate a previously defined extension or if that is not available,
                // create a lazy lookup to a factory from the list of vanilla factories.
                // Lazy because we currently can not know whether a factory will only
                // become available due to a subsequent provider.
                $innerFactory = $this->factories[$id] ?? static function (ContainerInterface $c) use (&‪$factories, $id) {
                    return isset(‪$factories[$id]) ? ‪$factories[$id]($c) : null;
                };
 
                $this->factories[$id] = static function (ContainerInterface $container) use ($extension, $innerFactory) {
                    $previous = $innerFactory($container);
                    return $extension($container, $previous);
                };
            }
        }
 
        // Add factories to the list of factories for services that were not extended.
        // (i.e those that have not been specified in getExtensions)
        $this->factories += ‪$factories;
    }
 
    public function ‪has(string $id): bool
    {
        return array_key_exists($id, $this->entries) || array_key_exists($id, $this->factories);
    }
 
    private function ‪create(string $id)
    {
        $factory = $this->factories[$id] ?? null;
 
        if ((bool)$factory) {
            // Remove factory as it is no longer required.
            // Set factory to false to be able to detect
            // cyclic dependency loops.
            $this->factories[$id] = false;
 
            return $this->entries[$id] = $factory($this);
        }
        if (array_key_exists($id, $this->entries)) {
            // This condition is triggered in the unlikely case that the entry is null
            // Note: That is because the coalesce operator used in get() can not handle that
            return $this->entries[$id];
        }
        if ($factory === null) {
            throw new NotFoundException('Container entry "' . $id . '" is not available.', 1519978105);
        }
        // if ($factory === false)
        throw new ContainerException('Container entry "' . $id . '" is part of a cyclic dependency chain.', 1520175002);
    }
 
    public function get(string $id)
    {
        return $this->entries[$id] ?? $this->‪create($id);
    }
}