Handle private streams better (failed to show profile before)

lib/privatestreamexception.php

@@ -0,0 +1,31 @@
+<?php
+if (!defined('GNUSOCIAL')) { exit(1); }
+
+/**
+ * An exception for private streams
+ *
+ * @category  Exception
+ * @package   GNUsocial
+ * @author    Mikael Nordfeldth <mmn@hethane.se>
+ * @copyright 2016 Free Software Foundation, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ */
+
+class PrivateStreamException extends AuthorizationException
+{
+    var $owner = null;  // owner of the private stream
+    var $reader = null; // reader, may be null if not logged in
+
+    public function __construct(Profile $owner, Profile $reader=null)
+    {
+        $this->owner = $owner;
+        $this->reader = $reader;
+
+        // TRANS: Message when a private stream attemps to be read by unauthorized third party.
+        $msg = sprintf(_m('This stream is protected and only authorized subscribers may see its contents.'));
+
+        // If $reader is a profile, authentication has been made but still not accepted (403),
+        // otherwise authentication may give access to this resource (401).
+        parent::__construct($msg, ($reader instanceof Profile ? 403 : 401));
+    }
+}