Sanitize class names before registerService/query

Leading backslashes are removed, so a `registerService('\\OC\\Foo')`
can still be resolved with `query('OC\\Foo')`.

lib/private/appframework/utility/simplecontainer.php

@@ -99,6 +99,7 @@ class SimpleContainer extends Container implements IContainer {
 	 * @throws QueryException if the query could not be resolved
 	 */
 	public function query($name) {
+		$name = $this->sanitizeName($name);
 		if ($this->offsetExists($name)) {
 			return $this->offsetGet($name);
 		} else {
@@ -128,6 +129,7 @@ class SimpleContainer extends Container implements IContainer {
 	 * @param bool $shared
 	 */
 	public function registerService($name, Closure $closure, $shared = true) {
+		$name = $this->sanitizeName($name);
 		if (isset($this[$name]))  {
 			unset($this[$name]);
 		}
@@ -151,4 +153,12 @@ class SimpleContainer extends Container implements IContainer {
 		});
 	}
 
+	/*
+	 * @param string $name
+	 * @return string
+	 */
+	protected function sanitizeName($name) {
+		return ltrim($name, '\\');
+	}
+
 }

tests/lib/appframework/utility/SimpleContainerTest.php

@@ -167,6 +167,25 @@ class SimpleContainerTest extends \Test\TestCase {
         $this->assertEquals('abc', $this->container->query('test1'));
     }
 
+    public function sanitizeNameProvider() {
+        return [
+            ['ABC\\Foo', 'ABC\\Foo'],
+            ['\\ABC\\Foo', '\\ABC\\Foo'],
+            ['\\ABC\\Foo', 'ABC\\Foo'],
+            ['ABC\\Foo', '\\ABC\\Foo'],
+        ];
+    }
+
+    /**
+     * @dataProvider sanitizeNameProvider
+     */
+    public function testSanitizeName($register, $query) {
+        $this->container->registerService($register, function() {
+            return 'abc';
+        });
+        $this->assertEquals('abc', $this->container->query($query));
+    }
+
     /**
      * @expectedException \OCP\AppFramework\QueryException
      */