3 files changed, 180 insertions, 2 deletions
diff --git a/Core/Authorization/AccessDecisionManager.php b/Core/Authorization/AccessDecisionManager.php
index 6e5effb..84856f6 100644
--- a/Core/Authorization/AccessDecisionManager.php
+++ b/Core/Authorization/AccessDecisionManager.php
@@ -22,6 +22,10 @@ use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
  */
 class AccessDecisionManager implements AccessDecisionManagerInterface
 {
+    const STRATEGY_AFFIRMATIVE = 'affirmative';
+    const STRATEGY_CONSENSUS   = 'consensus';
+    const STRATEGY_UNANIMOUS   = 'unanimous';
+
     private $voters;
     private $strategy;
     private $allowIfAllAbstainDecisions;
@@ -37,14 +41,19 @@ class AccessDecisionManager implements AccessDecisionManagerInterface
      *
      * @throws \InvalidArgumentException
      */
-    public function __construct(array $voters, $strategy = 'affirmative', $allowIfAllAbstainDecisions = false, $allowIfEqualGrantedDeniedDecisions = true)
+    public function __construct(array $voters, $strategy = self::STRATEGY_AFFIRMATIVE, $allowIfAllAbstainDecisions = false, $allowIfEqualGrantedDeniedDecisions = true)
     {
         if (!$voters) {
             throw new \InvalidArgumentException('You must at least add one voter.');
         }
 
+        $strategyMethod = 'decide'.ucfirst($strategy);
+        if (!is_callable(array($this, $strategyMethod))) {
+            throw new \InvalidArgumentException(sprintf('The strategy "%s" is not supported.', $strategy));
+        }
+
         $this->voters = $voters;
-        $this->strategy = 'decide'.ucfirst($strategy);
+        $this->strategy = $strategyMethod;
         $this->allowIfAllAbstainDecisions = (bool) $allowIfAllAbstainDecisions;
         $this->allowIfEqualGrantedDeniedDecisions = (bool) $allowIfEqualGrantedDeniedDecisions;
     }
diff --git a/Core/Authorization/ExpressionLanguage.php b/Core/Authorization/ExpressionLanguage.php
new file mode 100644
index 0000000..f9012b7
--- /dev/null
+++ b/Core/Authorization/ExpressionLanguage.php
@@ -0,0 +1,57 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * 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;
+
+use Symfony\Component\ExpressionLanguage\ExpressionLanguage as BaseExpressionLanguage;
+
+/**
+ * Adds some function to the default ExpressionLanguage.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ExpressionLanguage extends BaseExpressionLanguage
+{
+    protected function registerFunctions()
+    {
+        parent::registerFunctions();
+
+        $this->register('is_anonymous', function () {
+            return '$trust_resolver->isAnonymous($token)';
+        }, function (array $variables) {
+            return $variables['trust_resolver']->isAnonymous($variables['token']);
+        });
+
+        $this->register('is_authenticated', function () {
+            return '$token && !$trust_resolver->isAnonymous($token)';
+        }, function (array $variables) {
+            return $variables['token'] && !$variables['trust_resolver']->isAnonymous($variables['token']);
+        });
+
+        $this->register('is_fully_authenticated', function () {
+            return '$trust_resolver->isFullFledged($token)';
+        }, function (array $variables) {
+            return $variables['trust_resolver']->isFullFledged($variables['token']);
+        });
+
+        $this->register('is_remember_me', function () {
+            return '$trust_resolver->isRememberMe($token)';
+        }, function (array $variables) {
+            return $variables['trust_resolver']->isRememberMe($variables['token']);
+        });
+
+        $this->register('has_role', function ($role) {
+            return sprintf('in_array(%s, $roles)', $role);
+        }, function (array $variables, $role) {
+            return in_array($role, $variables['roles']);
+        });
+    }
+}
diff --git a/Core/Authorization/Voter/ExpressionVoter.php b/Core/Authorization/Voter/ExpressionVoter.php
new file mode 100644
index 0000000..3263803
--- /dev/null
+++ b/Core/Authorization/Voter/ExpressionVoter.php
@@ -0,0 +1,112 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * 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\Security\Core\Authentication\Token\TokenInterface;
+use Symfony\Component\Security\Core\Authentication\AuthenticationTrustResolverInterface;
+use Symfony\Component\Security\Core\Authorization\ExpressionLanguage;
+use Symfony\Component\Security\Core\Role\RoleHierarchyInterface;
+use Symfony\Component\ExpressionLanguage\Expression;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * ExpressionVoter votes based on the evaluation of an expression.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ExpressionVoter implements VoterInterface
+{
+    private $expressionLanguage;
+    private $trustResolver;
+    private $roleHierarchy;
+
+    /**
+     * Constructor.
+     *
+     * @param ExpressionLanguage                   $expressionLanguage
+     * @param AuthenticationTrustResolverInterface $trustResolver
+     * @param RoleHierarchyInterface|null          $roleHierarchy
+     */
+    public function __construct(ExpressionLanguage $expressionLanguage, AuthenticationTrustResolverInterface $trustResolver, RoleHierarchyInterface $roleHierarchy = null)
+    {
+        $this->expressionLanguage = $expressionLanguage;
+        $this->trustResolver = $trustResolver;
+        $this->roleHierarchy = $roleHierarchy;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsAttribute($attribute)
+    {
+        return $attribute instanceof Expression;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsClass($class)
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function vote(TokenInterface $token, $object, array $attributes)
+    {
+        $result = VoterInterface::ACCESS_ABSTAIN;
+        $variables = null;
+        foreach ($attributes as $attribute) {
+            if (!$this->supportsAttribute($attribute)) {
+                continue;
+            }
+
+            if (null === $variables) {
+                $variables = $this->getVariables($token, $object);
+            }
+
+            $result = VoterInterface::ACCESS_DENIED;
+            if ($this->expressionLanguage->evaluate($attribute, $variables)) {
+                return VoterInterface::ACCESS_GRANTED;
+            }
+        }
+
+        return $result;
+    }
+
+    private function getVariables(TokenInterface $token, $object)
+    {
+        if (null !== $this->roleHierarchy) {
+            $roles = $this->roleHierarchy->getReachableRoles($token->getRoles());
+        } else {
+            $roles = $token->getRoles();
+        }
+
+        $variables = array(
+            'token' => $token,
+            'user' => $token->getUser(),
+            'object' => $object,
+            'roles' => array_map(function ($role) { return $role->getRole(); }, $roles),
+            'trust_resolver' => $this->trustResolver,
+        );
+
+        // this is mainly to propose a better experience when the expression is used
+        // in an access control rule, as the developer does not know that it's going
+        // to be handled by this voter
+        if ($object instanceof Request) {
+            $variables['request'] = $object;
+        }
+
+        return $variables;
+    }
+}