Add condition to handle empty input (#7)

Author: shivammathur

cs2pr

@@ -32,16 +32,18 @@ if ($argc === 1) {
 $exit = 0;
 $root = simplexml_load_string($xml);
 
-foreach($root as $file) {
-    $filename = (string)$file['name'];
+if($root) {
+    foreach($root as $file) {
+        $filename = (string)$file['name'];
 
-    foreach($file as $error) {
-        $type = (string) $error['severity'];
-        $line = (string) $error['line'];
-        $message = (string) $error['message'];
+        foreach($file as $error) {
+            $type = (string) $error['severity'];
+            $line = (string) $error['line'];
+            $message = (string) $error['message'];
 
-        annotateCheck(annotateType($type), relativePath($filename), $line, $message);
-        $exit = 1;
+            annotateCheck(annotateType($type), relativePath($filename), $line, $message);
+            $exit = 1;
+        }
     }
 }