Create a UI under Admin > Settings > Comments where you can limit

comments only to registered users.  It's simplistic, but is better
than adding a permission since generally this setting will be used
Gallery-wide.

Fixes ticket #1002

modules/comment/controllers/admin_comments.php

@@ -0,0 +1,52 @@
+<?php defined("SYSPATH") or die("No direct script access.");
+/**
+ * Gallery - a web based photo album viewer and editor
+ * Copyright (C) 2000-2010 Bharat Mediratta
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+class Admin_Comments_Controller extends Admin_Controller {
+  public function index() {
+    $view = new Admin_View("admin.html");
+    $view->page_title = t("Comment settings");
+    $view->content = new View("admin_comments.html");
+    $view->content->form = $this->_get_admin_form();
+    print $view;
+  }
+
+  public function save() {
+    access::verify_csrf();
+    $form = $this->_get_admin_form();
+    $form->validate();
+    module::set_var("comment", "access_permissions",
+                    $form->comment_settings->access_permissions->value);
+    message::success(t("Comment settings updated"));
+    url::redirect("admin/comments");
+  }
+
+  private function _get_admin_form() {
+    $form = new Forge("admin/comments/save", "", "post",
+                      array("id" => "g-comments-admin-form"));
+    $comment_settings = $form->group("comment_settings")->label(t("Permissions"));
+    $comment_settings->dropdown("access_permissions")
+      ->label(t("Who can leave comments?"))
+      ->options(array("everybody" => t("Everybody"),
+                      "registered_users" => t("Only registered users")))
+      ->selected(module::get_var("comment", "access_permissions"));
+    $comment_settings->submit("save")->value(t("Save"));
+    return $form;
+  }
+}
+