Implement resettable containers

stof · stof · commit 715daca90894 · 2015-07-03T14:39:59.000+02:00
This allows to remove references to all services during shutdown, giving
much more chances to destruct services and the container through
refcounting rather than waiting GC, as it will break cycles between the
container and container-aware services.
diff --git a/src/Symfony/Component/DependencyInjection/CHANGELOG.md b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
@@ -7,6 +7,7 @@ CHANGELOG
  * allowed specifying a directory to recursively load all configuration files it contains
  * deprecated the concept of scopes
  * added `Definition::setShared()` and `Definition::isShared()`
+ * added ResettableContainerInterface to be able to reset the container to release memory on shutdown
 
 2.7.0
 -----
diff --git a/src/Symfony/Component/DependencyInjection/Container.php b/src/Symfony/Component/DependencyInjection/Container.php
@@ -60,7 +60,7 @@
  *
  * @api
  */
-class Container implements IntrospectableContainerInterface
+class Container implements IntrospectableContainerInterface, ResettableContainerInterface
 {
     /**
      * @var ParameterBagInterface
@@ -375,6 +375,18 @@ public function initialized($id)
         return isset($this->services[$id]) || array_key_exists($id, $this->services);
     }
 
+    /**
+     * Clears shared services from the container.
+     */
+    public function reset()
+    {
+        if (!empty($this->scopedServices)) {
+            throw new RuntimeException('Resetting the container is not allowed when a scope is active.');
+        }
+
+        $this->services = array();
+    }
+
     /**
      * Gets all service ids.
      *
diff --git a/src/Symfony/Component/DependencyInjection/ResettableContainerInterface.php b/src/Symfony/Component/DependencyInjection/ResettableContainerInterface.php
@@ -0,0 +1,27 @@
+<?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\DependencyInjection;
+
+/**
+ * ResettableContainerInterface defines additional resetting functionality
+ * for containers, allowing to release shared services when the container is
+ * not needed anymore.
+ *
+ * @author Christophe Coevoet <stof@notk.org>
+ */
+interface ResettableContainerInterface extends ContainerInterface
+{
+    /**
+     * Resets shared services from the container.
+     */
+    public function reset();
+}
diff --git a/src/Symfony/Component/DependencyInjection/Tests/ContainerTest.php b/src/Symfony/Component/DependencyInjection/Tests/ContainerTest.php
@@ -320,6 +320,49 @@ public function testInitialized()
         $this->assertTrue($sc->initialized('alias'), '->initialized() returns true for alias if aliased service is initialized');
     }
 
+    public function testReset()
+    {
+        $c = new Container();
+        $c->set('bar', new \stdClass());
+
+        $c->reset();
+
+        $this->assertNull($c->get('bar', ContainerInterface::NULL_ON_INVALID_REFERENCE));
+    }
+
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\RuntimeException
+     * @expectedExceptionMessage Resetting the container is not allowed when a scope is active.
+     * @group legacy
+     */
+    public function testCannotResetInActiveScope()
+    {
+        $c = new Container();
+        $c->addScope(new Scope('foo'));
+        $c->set('bar', new \stdClass());
+
+        $c->enterScope('foo');
+
+        $c->reset();
+    }
+
+    /**
+     * @group legacy
+     */
+    public function testResetAfterLeavingScope()
+    {
+        $c = new Container();
+        $c->addScope(new Scope('foo'));
+        $c->set('bar', new \stdClass());
+
+        $c->enterScope('foo');
+        $c->leaveScope('foo');
+
+        $c->reset();
+
+        $this->assertNull($c->get('bar', ContainerInterface::NULL_ON_INVALID_REFERENCE));
+    }
+
     /**
      * @group legacy
      */
diff --git a/src/Symfony/Component/HttpKernel/Kernel.php b/src/Symfony/Component/HttpKernel/Kernel.php
@@ -13,6 +13,7 @@
 
 use Symfony\Bridge\ProxyManager\LazyProxy\Instantiator\RuntimeInstantiator;
 use Symfony\Bridge\ProxyManager\LazyProxy\PhpDumper\ProxyDumper;
+use Symfony\Component\DependencyInjection\ResettableContainerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Dumper\PhpDumper;
@@ -180,6 +181,10 @@ public function shutdown()
             $bundle->setContainer(null);
         }
 
+        if ($this->container instanceof ResettableContainerInterface) {
+            $this->container->reset();
+        }
+
         $this->container = null;
     }
 
