minor #1793 use a lazy loading service locator for decoders (xabbuh)

This PR was merged into the 2.2-dev branch.

Discussion
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use a lazy loading service locator for decoders

part of #1790

Commits
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aaa5681 use a lazy loading service locator for decoders

Author: xabbuh

Decoder/ContainerDecoderProvider.php

@@ -11,6 +11,7 @@
 
 namespace FOS\RestBundle\Decoder;
 
+use Psr\Container\ContainerInterface as PsrContainerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -26,11 +27,15 @@ class ContainerDecoderProvider implements DecoderProviderInterface
     /**
      * Constructor.
      *
-     * @param ContainerInterface $container The container from which the actual decoders are retrieved
-     * @param array              $decoders  List of key (format) value (service ids) of decoders
+     * @param PsrContainerInterface $container The container from which the actual decoders are retrieved
+     * @param array                 $decoders  List of key (format) value (service ids) of decoders
      */
-    public function __construct(ContainerInterface $container, array $decoders)
+    public function __construct($container, array $decoders)
     {
+        if (!$container instanceof PsrContainerInterface && !$container instanceof ContainerInterface) {
+            throw new \InvalidArgumentException(sprintf('The container must be an instance of %s or %s (%s given).', PsrContainerInterface::class, ContainerInterface::class, is_object($container) ? get_class($container) : gettype($container)));
+        }
+
         $this->container = $container;
         $this->decoders = $decoders;
     }

DependencyInjection/FOSRestExtension.php

@@ -13,6 +13,7 @@
 
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ChildDefinition;
+use Symfony\Component\DependencyInjection\Compiler\ServiceLocatorTagPass;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\DefinitionDecorator;
 use Symfony\Component\DependencyInjection\Loader\XmlFileLoader;
@@ -151,6 +152,17 @@ private function loadBodyListener(array $config, XmlFileLoader $loader, Containe
 
             $container->getDefinition('fos_rest.decoder_provider')->replaceArgument(1, $config['body_listener']['decoders']);
 
+            if (class_exists(ServiceLocatorTagPass::class)) {
+                $decoderServicesMap = array();
+
+                foreach ($config['body_listener']['decoders'] as $id) {
+                    $decoderServicesMap[$id] = new Reference($id);
+                }
+
+                $decodersServiceLocator = ServiceLocatorTagPass::register($container, $decoderServicesMap);
+                $container->getDefinition('fos_rest.decoder_provider')->replaceArgument(0, $decodersServiceLocator);
+            }
+
             $arrayNormalizer = $config['body_listener']['array_normalizer'];
 
             if (null !== $arrayNormalizer['service']) {