--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/program/include/rcmail_string_replacer.php	Thu Jan 04 15:52:31 2018 -0500
@@ -0,0 +1,64 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcmail_string_replacer.php                            |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2012-2013, The Roundcube Dev Team                       |
+ |                                                                       |
+ | Licensed under the GNU General Public License version 3 or            |
+ | any later version with exceptions for skins & plugins.                |
+ | See the README file for a full license statement.                     |
+ |                                                                       |
+ | PURPOSE:                                                              |
+ |   Turn URLs and email addresses into clickable links                  |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Thomas Bruederli <roundcube@gmail.com>                        |
+ +-----------------------------------------------------------------------+
+*/
+
+/**
+ * Helper class for turning URLs and email addresses in plaintext content
+ * into clickable links.
+ *
+ * @package    Webmail
+ * @subpackage Utils
+ */
+class rcmail_string_replacer extends rcube_string_replacer
+{
+    /**
+     * Callback function used to build mailto: links around e-mail strings
+     *
+     * This also adds an onclick-handler to open the Rouncube compose message screen on such links
+     *
+     * @param array $matches Matches result from preg_replace_callback
+     *
+     * @return int Index of saved string value
+     * @see rcube_string_replacer::mailto_callback()
+     */
+    public function mailto_callback($matches)
+    {
+        $href   = $matches[1];
+        $suffix = $this->parse_url_brackets($href);
+        $email  = $href;
+
+        if (strpos($email, '?')) {
+            list($email,) = explode('?', $email);
+        }
+
+        // skip invalid emails
+        if (!rcube_utils::check_email($email, false)) {
+            return $matches[1];
+        }
+
+        $i = $this->add(html::a(array(
+            'href'    => 'mailto:' . $href,
+            'onclick' => "return ".rcmail_output::JS_OBJECT_NAME.".command('compose','".rcube::JQ($href)."',this)",
+            ),
+            rcube::Q($href)) . $suffix);
+
+        return $i >= 0 ? $this->get_replacement($i) : '';
+    }
+}