Add config and help item for exact user search option

Change-Id: I644491740622d242677c06bb24779e676ad93838
Signed-off-by: Richard Mansfield <richard.mansfield@catalyst.net.nz>

htdocs/search/internal/lang/en.utf8/help/forms/pluginconfig.exactusersearch.html

+<h3>Exact user searches</h3>
+
+<p>If your site has a lot of users and uses a PostgreSQL database,
+user searches will be faster with exact user searching enabled.
+The setting will still work with MySQL databases, but is unlikely
+to significantly increase search performance.</p>
+
+<p>However, partial matches on profile fields will not return results,
+so if for example you have a user called "Nigel", then typing "Nige"
+into the search box will not find that user.</p>

htdocs/search/internal/lang/en.utf8/search.internal.php

+<?php
+/**
+ * Mahara: Electronic portfolio, weblog, resume builder and social networking
+ * Copyright (C) 2006-2009 Catalyst IT Ltd and others; see:
+ *                         http://wiki.mahara.org/Contributors
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ * @package    mahara
+ * @subpackage lang
+ * @author     Catalyst IT Ltd
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL
+ * @copyright  (C) 2006-2009 Catalyst IT Ltd http://catalyst.net.nz
+ *
+ */
+
+defined('INTERNAL') || die();
+
+$string['exactusersearch'] = 'Exact user searches';
+$string['exactusersearchdescription'] = 'If checked, results from the Search Users box and Find Friends page are only returned for users whose profile fields match entire search terms.';

htdocs/search/internal/lib.php

@@ -37,6 +37,34 @@ class PluginSearchInternal extends PluginSearch {
         return false;
     }
 
+    public static function has_config() {
+        return true;
+    }
+
+    public static function get_config_options() {
+        return array(
+            'elements'   => array(
+                'exactusersearch' =>  array(
+                    'title'        => get_string('exactusersearch', 'search.internal'),
+                    'description'  => get_string('exactusersearchdescription', 'search.internal'),
+                    'help'         => true,
+                    'type'         => 'checkbox',
+                    'defaultvalue' => get_config_plugin('search', 'internal', 'exactusersearch'),
+                ),
+            ),
+        );
+    }
+
+    public function save_config_options($values) {
+        set_config_plugin('search', 'internal', 'exactusersearch', (int) $values['exactusersearch']);
+    }
+
+    public static function postinst($prevversion) {
+        if ($prevversion == 0) {
+            set_config_plugin('search', 'internal', 'exactusersearch', 1);
+        }
+    }
+
     /**
      * Implement user searching with SQL
      *