by Dave Reid: Added a basic realname auto-completion callback.

realname.module

@@ -38,6 +38,12 @@ function realname_menu() {
     'file' => 'realname.admin.inc',
   );
 
+  $items['realname/autocomplete'] = array(
+    'page callback' => 'realname_autocomplete',
+    'access arguments' => array('access user profiles'),
+    'type' => MENU_CALLBACK,
+  );
+
   return $items;
 }
 
@@ -243,3 +249,27 @@ function realname_delete_all() {
 /**
  * @} End of "addtogroup realname".
  */
+
+/**
+ * Menu callback; Retrieve a JSON object containing autocomplete suggestions
+ * for existing users based on their generated real names.
+ */
+function realname_autocomplete($string = '') {
+  $matches = array();
+
+  if ($string) {
+    $query = db_select('users', 'u');
+    $query->leftJoin('realname', 'rn', 'u.uid = rn.uid');
+    $query->fields('u', array('uid'));
+    $query->condition('rn.realname', db_like($string) . '%', 'LIKE');
+    $query->range(0, 10);
+    $uids = $query->execute()->fetchCol();
+    $accounts = user_load_multiple($uids);
+
+    foreach ($accounts as $account) {
+      $matches[$account->name] = format_username($account);
+    }
+  }
+
+  drupal_json_output($matches);
+}