[ClassLoader] added a debug class loader

DebugUniversalClassLoader.php

@@ -0,0 +1,62 @@
+<?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\ClassLoader;
+
+/**
+ * Checks that the class is actually declared in the included file.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class DebugUniversalClassLoader extends UniversalClassLoader
+{
+    /**
+     * Replaces all regular UniversalClassLoader instances by a DebugUniversalClassLoader ones.
+     */
+    static public function enable()
+    {
+        if (!is_array($functions = spl_autoload_functions())) {
+            return;
+        }
+
+        foreach ($functions as $function) {
+            spl_autoload_unregister($function);
+        }
+
+        foreach ($functions as $function) {
+            if (is_array($function) && $function[0] instanceof UniversalClassLoader) {
+                $loader = new static();
+                $loader->registerNamespaceFallback($function[0]->getNamespaceFallback());
+                $loader->registerPrefixFallback($function[0]->getPrefixFallback());
+                $loader->registerNamespaces($function[0]->getNamespaces());
+                $loader->registerPrefixes($function[0]->getPrefixes());
+
+                $function[0] = $loader;
+            }
+
+            spl_autoload_register($function);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function loadClass($class)
+    {
+        if ($file = $this->findFile($class)) {
+            require $file;
+
+            if (!class_exists($class, false) && !interface_exists($class, false)) {
+                throw new \Exception(sprintf('The autoloader expected class "%s" to be defined in file "%s". You probably have a typo in the namespace or the class name.', $class, $file));
+            }
+        }
+    }
+}