<?php 
 
/* 
 * This file is part of the Symfony package. 
 * 
 * (c) Fabien Potencier <[email protected]> 
 * 
 * For the full copyright and license information, please view the LICENSE 
 * file that was distributed with this source code. 
 */ 
 
namespace Symfony\Component\Security\Core\Authorization\Voter; 
 
use Symfony\Component\ExpressionLanguage\Expression; 
use Symfony\Component\HttpFoundation\Request; 
use Symfony\Component\Security\Core\Authentication\AuthenticationTrustResolverInterface; 
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface; 
use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface; 
use Symfony\Component\Security\Core\Authorization\ExpressionLanguage; 
use Symfony\Component\Security\Core\Role\RoleHierarchyInterface; 
 
/** 
 * ExpressionVoter votes based on the evaluation of an expression. 
 * 
 * @author Fabien Potencier <[email protected]> 
 */ 
class ExpressionVoter implements CacheableVoterInterface 
{ 
    private $expressionLanguage; 
    private $trustResolver; 
    private $authChecker; 
    private $roleHierarchy; 
 
    public function __construct(ExpressionLanguage $expressionLanguage, AuthenticationTrustResolverInterface $trustResolver, AuthorizationCheckerInterface $authChecker, ?RoleHierarchyInterface $roleHierarchy = null) 
    { 
        $this->expressionLanguage = $expressionLanguage; 
        $this->trustResolver = $trustResolver; 
        $this->authChecker = $authChecker; 
        $this->roleHierarchy = $roleHierarchy; 
    } 
 
    public function supportsAttribute(string $attribute): bool 
    { 
        return false; 
    } 
 
    public function supportsType(string $subjectType): bool 
    { 
        return true; 
    } 
 
    /** 
     * {@inheritdoc} 
     */ 
    public function vote(TokenInterface $token, $subject, array $attributes) 
    { 
        $result = VoterInterface::ACCESS_ABSTAIN; 
        $variables = null; 
        foreach ($attributes as $attribute) { 
            if (!$attribute instanceof Expression) { 
                continue; 
            } 
 
            if (null === $variables) { 
                $variables = $this->getVariables($token, $subject); 
            } 
 
            $result = VoterInterface::ACCESS_DENIED; 
            if ($this->expressionLanguage->evaluate($attribute, $variables)) { 
                return VoterInterface::ACCESS_GRANTED; 
            } 
        } 
 
        return $result; 
    } 
 
    private function getVariables(TokenInterface $token, $subject): array 
    { 
        $roleNames = $token->getRoleNames(); 
 
        if (null !== $this->roleHierarchy) { 
            $roleNames = $this->roleHierarchy->getReachableRoleNames($roleNames); 
        } 
 
        $variables = [ 
            'token' => $token, 
            'user' => $token->getUser(), 
            'object' => $subject, 
            'subject' => $subject, 
            'role_names' => $roleNames, 
            'trust_resolver' => $this->trustResolver, 
            'auth_checker' => $this->authChecker, 
        ]; 
 
        // this is mainly to propose a better experience when the expression is used 
        // in an access control rule, as the developer does not know that it's going 
        // to be handled by this voter 
        if ($subject instanceof Request) { 
            $variables['request'] = $subject; 
        } 
 
        return $variables; 
    } 
}