Do not enable profiler if xhprof is not installed on server + add ext…

…ension required on composer

DependencyInjection/JnsXhprofExtension.php

@@ -17,7 +17,7 @@ class JnsXhprofExtension extends Extension
     protected $resources = array(
         'services' => 'services.xml',
     );
-    
+
     /**
      * Loads the services based on your application configuration.
      *
@@ -30,9 +30,9 @@ public function load(array $configs, ContainerBuilder $container)
         $configuration = new Configuration();
         $config = $processor->process($configuration->getConfigTree(), $configs);
 
-        if ($config['enabled']) {
+        if ($config['enabled'] && function_exists('xhprof_enable')) {
             $this->loadDefaults($container);
-            
+
             foreach ($config as $key => $value) {
                 $container->setParameter($this->getAlias().'.'.$key, $value);
             }

composer.json

@@ -11,7 +11,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.2"
+        "php": ">=5.3.2",
+        "ext-xhprof": "*"
     },
     "autoload": {
         "psr-0": { "Jns\\Bundle\\XhprofBundle": "" }