Index: modules/user.views.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/views/modules/user.views.inc,v
retrieving revision 1.55
diff -u -p -u -p -r1.55 user.views.inc
--- modules/user.views.inc	2 Dec 2008 19:37:08 -0000	1.55
+++ modules/user.views.inc	5 Feb 2009 09:28:09 -0000
@@ -312,6 +312,13 @@ function user_views_plugins() {
         'parent' => 'fixed', // so that the parent class is included
       ),
     ),
+    'argument validator' => array(
+      'user' => array(
+        'title' => t('User'),
+        'handler' => 'views_plugin_argument_validate_user',
+        'path' => drupal_get_path('module', 'views') . '/modules/user', // not necessary for most modules
+      ),
+    ),
   );
 }
 
Index: modules/user/views_plugin_argument_validate_user.inc
===================================================================
RCS file: modules/user/views_plugin_argument_validate_user.inc
diff -N modules/user/views_plugin_argument_validate_user.inc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ modules/user/views_plugin_argument_validate_user.inc	5 Feb 2009 09:28:09 -0000
@@ -0,0 +1,90 @@
+<?php
+// $Id$
+
+/**
+ * Validate whether an argument is a valid user.
+ *
+ * This supports either numeric arguments (UID) or strings (username) and
+ * converts either one into the user's UID.  This validator also sets the
+ * argument's title to the username.
+ */
+class views_plugin_argument_validate_user extends views_plugin_argument_validate {
+  function validate_form(&$form, &$form_state) {
+    $form['user_argument_type'] = array(
+      '#type' => 'radios',
+      '#title' => t('Type of user argument to allow'),
+      '#options' => array(
+        'uid' => t('Only allow numeric UIDs'),
+        'name' => t('Only allow string usernames'),
+        'either' => t('Allow both numeric UIDs and string usernames'),
+      ),
+      '#default_value' => $this->argument->options['user_argument_type'],
+    );
+
+    $form['restrict_user_roles'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Restrict user based on role'),
+      '#default_value' => !empty($this->argument->options['restrict_user_roles']),
+    );
+
+    $form['user_roles'] = array(
+      '#type' => 'select',
+      '#multiple' => TRUE,
+      '#title' => t('Restrict to the selected roles'),
+      '#options' => user_roles(TRUE),
+      '#default_value' => $this->argument->options['user_roles'],
+      '#description' => t('If no roles are selected, users from any role will be allowed.'),
+      '#process' => array('views_process_dependency'),
+      '#dependency' => array(
+        'edit-options-restrict-user-roles' => array(1),
+      ),
+    );
+  }
+  
+  function validate_argument($argument) {
+    $type = $this->argument->options['user_argument_type'];
+    // is_numeric() can return false positives, so we ensure it's an integer.
+    // However, is_integer() will always fail, since $argument is a string.
+    if (is_numeric($argument) && $argument == (int)$argument) {
+      if ($type == 'uid' || $type == 'either') {
+        $where = 'uid = %d';
+      }
+    }
+    else {
+      if ($type == 'name' || $type == 'either') {
+        $where = "name = '%s'";
+      }
+    }
+
+    // If we don't have a WHERE clause, the argument is invalid.
+    if (empty($where)) {
+      return FALSE;
+    }
+
+    $query = "SELECT uid, name FROM {users} WHERE $where";
+    $account = db_fetch_object(db_query($query, $argument));
+    if (empty($account)) {
+      // User not found.
+      return FALSE;
+    }
+
+    // See if we're filtering users based on roles.
+    if (!empty($this->argument->options['restrict_user_roles']) && !empty($this->argument->options['user_roles'])) {
+      $roles = $this->argument->options['user_roles'];
+      $acccont->roles = array();
+      $account->roles[] = $account->uid ? DRUPAL_AUTHENTICATED_RID : DRUPAL_ANONYMOUS_RID;
+      $result = db_query('SELECT rid FROM {users_roles} WHERE uid = %d', $account->uid);
+      while ($role = db_fetch_object($result)) {
+        $account->roles[] = $role->rid;
+      }
+      if (!(bool)array_intersect($account->roles, $roles)) {
+        return FALSE;
+      }
+    }
+
+    $this->argument->argument = $account->uid;
+    $this->argument->validated_title = check_plain($account->name);
+    return TRUE;
+  }
+}
+