BaseRequirementsFulfilledValidator.php

<?php

namespace Drupal\package_manager\Validator;

use Drupal\package_manager\Event\PreApplyEvent;
use Drupal\package_manager\Event\PreCreateEvent;
use Drupal\package_manager\Event\PreOperationStageEvent;
use Drupal\package_manager\Event\PreRequireEvent;
use Drupal\package_manager\Event\StatusCheckEvent;
use Drupal\system\SystemManager;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Validates that base requirements do not have any errors.
 *
 * Base requirements are the sorts of things that must be in a good state for
 * Package Manager to be usable. For example, Composer must be available and
 * usable; certain paths of the file system must be writable; the current site
 * cannot be part of a multisite, and so on.
 *
 * This validator simply stops event propagation if any of the validators before
 * it have added error results. Validators that check base requirements should
 * run before this validator (they can use
 * \Drupal\package_manager\Validator\BaseRequirementValidatorTrait to make this
 * easier). To ensure that all base requirement errors are shown to the user, no
 * base requirement validator should stop event propagation itself.
 *
 * Base requirement validators should not depend on each other or assume that
 * Composer is usable in the current environment.
 *
 * @see \Drupal\package_manager\Validator\BaseRequirementValidatorTrait
 */
final class BaseRequirementsFulfilledValidator implements EventSubscriberInterface {
    
    /**
     * The priority of this validator.
     *
     * @see ::getSubscribedEvents()
     *
     * @var int
     */
    public const PRIORITY = 200;
    
    /**
     * Validates that base requirements are fulfilled.
     *
     * @param \Drupal\package_manager\Event\PreOperationStageEvent $event
     *   The event.
     */
    public function validate(PreOperationStageEvent $event) : void {
        // If there are any errors from the validators which ran before this one,
        // base requirements are not fulfilled. Stop any further validators from
        // running.
        if ($event->getResults(SystemManager::REQUIREMENT_ERROR)) {
            $event->stopPropagation();
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() : array {
        return [
            PreCreateEvent::class => [
                'validate',
                self::PRIORITY,
            ],
            PreRequireEvent::class => [
                'validate',
                self::PRIORITY,
            ],
            PreApplyEvent::class => [
                'validate',
                self::PRIORITY,
            ],
            StatusCheckEvent::class => [
                'validate',
                self::PRIORITY,
            ],
        ];
    }

}