EntityTestRevlogAccessControlHandler.php

<?php

namespace Drupal\entity_test_revlog;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityAccessControlHandler;
use Drupal\Core\Session\AccountInterface;
use Drupal\entity_test_revlog\Entity\EntityTestWithRevisionLog;

/**
 * Defines the access control handler for test entity types.
 */
class EntityTestRevlogAccessControlHandler extends EntityAccessControlHandler {
    
    /**
     * {@inheritdoc}
     */
    protected function checkAccess(EntityInterface $entity, $operation, AccountInterface $account) {
        assert($entity instanceof EntityTestWithRevisionLog);
        // Access to revisions is based on labels, so access can vary by individual
        // revisions, since the 'name' field can vary by revision.
        $labels = explode(',', $entity->label());
        $labels = array_map('trim', $labels);
        if (in_array($operation, [
            'view',
            'view label',
            'view all revisions',
            'view revision',
        ], TRUE)) {
            return AccessResult::allowedIf(in_array($operation, $labels, TRUE));
        }
        elseif ($operation === 'revert') {
            return AccessResult::allowedIf(!$entity->isDefaultRevision() && !$entity->isLatestRevision() && in_array('revert', $labels, TRUE));
        }
        elseif ($operation === 'delete revision') {
            return AccessResult::allowedIf(!$entity->isLatestRevision() && in_array('delete revision', $labels, TRUE));
        }
        // No opinion.
        return AccessResult::neutral();
    }

}