symfony · fabpot · Aug 25, 2013 · stof · Sep 2, 2013
diff --git a/src/Symfony/Component/DependencyInjection/CHANGELOG.md b/src/Symfony/Component/DependencyInjection/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+2.4.0
+-----
+
+ * added support for expressions in service definitions
+
 2.2.0
 -----
 

diff --git a/src/Symfony/Component/DependencyInjection/ContainerBuilder.php b/src/Symfony/Component/DependencyInjection/ContainerBuilder.php
@@ -24,6 +24,7 @@
 use Symfony\Component\Config\Resource\ResourceInterface;
 use Symfony\Component\DependencyInjection\LazyProxy\Instantiator\InstantiatorInterface;
 use Symfony\Component\DependencyInjection\LazyProxy\Instantiator\RealServiceInstantiator;
+use Symfony\Component\PropertyAccess\PropertyAccess;
 
 /**
  * ContainerBuilder is a DI container that provides an API to easily describe services.
@@ -78,6 +79,11 @@ class ContainerBuilder extends Container implements TaggedContainerInterface
      */
     private $proxyInstantiator;
 
+    /**
+     * @var PropertyAccess|null
+     */
+    private $propertyAccessor;
+
     /**
      * Sets the track resources flag.
      *
@@ -993,11 +999,12 @@ public function createService(Definition $definition, $id, $tryProxy = true)
     }
 
     /**
-     * Replaces service references by the real service instance.
+     * Replaces service references by the real service instance and evaluates expressions.
      *
      * @param mixed $value A value
      *
-     * @return mixed The same value with all service references replaced by the real service instances
+     * @return mixed The same value with all service references replaced by
+     *               the real service instances and all expressions evaluated
      */
     public function resolveServices($value)
     {
@@ -1009,6 +1016,15 @@ public function resolveServices($value)
             $value = $this->get((string) $value, $value->getInvalidBehavior());
         } elseif ($value instanceof Definition) {
             $value = $this->createService($value, null);
+        } elseif ($value instanceof Expression) {
+            if (null === $this->propertyAccessor) {
+                if (!class_exists('Symfony\Component\PropertyAccess\PropertyAccess')) {
+                    throw new RuntimeException('Unable to use expressions as the Symfony PropertyAccess component is not installed.');
+                }
+                $this->propertyAccessor = PropertyAccess::createPropertyAccessor();
+            }
+
+            $value = $this->propertyAccessor->getValue($this->get($value->getId()), $value->getPath());
         }
 
         return $value;

diff --git a/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php b/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php
@@ -17,6 +17,7 @@
 use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\DependencyInjection\Expression;
 use Symfony\Component\DependencyInjection\Parameter;
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 use Symfony\Component\DependencyInjection\Exception\RuntimeException;
@@ -722,6 +723,7 @@ private function startClass($class, $baseClass, $namespace)
 use Symfony\Component\DependencyInjection\Exception\RuntimeException;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\DependencyInjection\Parameter;
+use Symfony\Component\PropertyAccess\PropertyAccess;
 $bagClass
 
 /**
@@ -732,6 +734,7 @@ private function startClass($class, $baseClass, $namespace)
  */
 class $class extends $baseClass
 {
+    private \$propertyAccessor;
 EOF;
     }
 
@@ -991,6 +994,18 @@ private function exportParameters($parameters, $path = '', $indent = 12)
     private function endClass()
     {
         return <<<EOF
+
+    private function getPropertyAccessor()
+    {
+        if (null === \$this->propertyAccessor) {
+            if (!class_exists('Symfony\Component\PropertyAccess\PropertyAccess')) {
+                throw new RuntimeException('Unable to use expressions as the Symfony PropertyAccess component is not installed.');
+            }
+            \$this->propertyAccessor = PropertyAccess::createPropertyAccessor();
+        }
+
+        return \$this->propertyAccessor;
+    }
 }
 
 EOF;
@@ -1197,6 +1212,8 @@ private function dumpValue($value, $interpolate = true)
             }
 
             return $this->getServiceCall((string) $value, $value);
+        } elseif ($value instanceof Expression) {
+            return sprintf("\$this->getPropertyAccessor()->getValue(%s, '%s')", $this->dumpValue(new Reference($value->getId())), $value->getPath());
         } elseif ($value instanceof Parameter) {
             return $this->dumpParameter($value);
         } elseif (true === $interpolate && is_string($value)) {

diff --git a/src/Symfony/Component/DependencyInjection/Expression.php b/src/Symfony/Component/DependencyInjection/Expression.php
@@ -0,0 +1,55 @@
+<?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;
+
+use Symfony\Component\DependencyInjection\Exception\RuntimeException;
+
+/**
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class Expression
+{
+    private $id;
+    private $path;
+
+    /**
+     * Constructor.
+     *
+     * @param string $id   A service identifier
+     * @param string $path A PropertyAccess path
+     */
+    public function __construct($id, $path)
+    {
+        $this->id = $id;
+        $this->path = $path;
+    }
+
+    /**
+     * Gets the service identifier of the expression.
+     *
+     * @return string The service identifier
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * Gets the property path.
+     *
+     * @return string The property path
+     */
+    public function getPath()
+    {
+        return $this->path;
+    }
+}
diff --git a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -16,6 +16,7 @@
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\DependencyInjection\Expression;
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 use Symfony\Component\Config\Resource\FileResource;
 use Symfony\Component\Yaml\Parser as YamlParser;
@@ -312,6 +313,11 @@ private function resolveServices($value)
         if (is_array($value)) {
             $value = array_map(array($this, 'resolveServices'), $value);
         } elseif (is_string($value) &&  0 === strpos($value, '@')) {
+            // is it an expression?
+            if (false !== $pos = strpos($value, '::')) {
+                return new Expression(substr($value, 1, $pos - 1), substr($value, $pos + 2));
+            }
+
             if (0 === strpos($value, '@@')) {
                 $value = substr($value, 1);
                 $invalidBehavior = null;

diff --git a/src/Symfony/Component/DependencyInjection/Loader/schema/dic/services/services-1.0.xsd b/src/Symfony/Component/DependencyInjection/Loader/schema/dic/services/services-1.0.xsd
@@ -140,6 +140,7 @@
     <xsd:attribute name="key" type="xsd:string" />
     <xsd:attribute name="index" type="xsd:integer" />
     <xsd:attribute name="on-invalid" type="xsd:string" />
+    <xsd:attribute name="path" type="xsd:string" />
     <xsd:attribute name="strict" type="boolean" />
   </xsd:complexType>
 
@@ -164,6 +165,7 @@
     <xsd:restriction base="xsd:string">
       <xsd:enumeration value="collection" />
       <xsd:enumeration value="service" />
+      <xsd:enumeration value="expression" />
       <xsd:enumeration value="string" />
       <xsd:enumeration value="constant" />
     </xsd:restriction>

diff --git a/src/Symfony/Component/DependencyInjection/SimpleXMLElement.php b/src/Symfony/Component/DependencyInjection/SimpleXMLElement.php
@@ -77,6 +77,9 @@ public function getArgumentsAsPhp($name, $lowercase = true)
 
                     $arguments[$key] = new Reference((string) $arg['id'], $invalidBehavior, $strict);
                     break;
+                case 'expression':
+                    $arguments[$key] = new Expression((string) $arg['id'], (string) $arg['path']);
+                    break;
                 case 'collection':
                     $arguments[$key] = $arg->getArgumentsAsPhp($name, false);
                     break;