MDL-29627 load the existing settings when the quiz settings are re-edited.

mod/quiz/accessmanager.php

@@ -92,6 +92,10 @@ class quiz_access_manager {
 
     /**
      * Add any form fields that the access rules require to the settings form.
+     *
+     * Note that the standard plugins do not use this mechanism, becuase all their
+     * settings are stored in the quiz table.
+     *
      * @param mod_quiz_mod_form $quizform the quiz settings form that is being built.
      * @param MoodleQuickForm $mform the wrapped MoodleQuickForm.
      */
@@ -105,6 +109,10 @@ class quiz_access_manager {
 
     /**
      * Save any submitted settings when the quiz settings form is submitted.
+     *
+     * Note that the standard plugins do not use this mechanism, becuase all their
+     * settings are stored in the quiz table.
+     *
      * @param object $quiz the data from the quiz form, including $quiz->id
      *      which is the is of the quiz being saved.
      */
@@ -115,6 +123,51 @@ class quiz_access_manager {
         }
     }
 
+    /**
+     * Load any settings required by the access rules. We try to do this with
+     * a single DB query.
+     *
+     * Note that the standard plugins do not use this mechanism, becuase all their
+     * settings are stored in the quiz table.
+     *
+     * @param int $quizid the quiz id.
+     * @return array setting value name => value. The value names should all
+     *      start with the name of the corresponding plugin to avoid collisions.
+     */
+    public static function load_settings($quizid) {
+        global $DB;
+        $rules = get_plugin_list_with_class('quizaccess', '', 'rule.php');
+
+        $allfields = '';
+        $alljoins = '{quiz} quiz';
+        $allparams = array('quizid' => $quizid);
+        foreach ($rules as $rule) {
+            list($fields, $joins, $params) = $rule::get_settings_sql($quizid);
+            if ($fields) {
+                if ($allfields) {
+                    $allfields .= ', ';
+                }
+                $allfields .= $fields;
+            }
+            if ($joins) {
+                $alljoins .= ' ' . $joins;
+            }
+            if ($params) {
+                $allparams += $params;
+            }
+        }
+        $data = (array) $DB->get_record_sql("
+                SELECT $allfields
+                  FROM $alljoins
+                 WHERE quiz.id = :quizid", $allparams);
+
+        foreach ($rules as $rule) {
+            $data += $rule::get_extra_settings($quizid);
+        }
+
+        return $data;
+    }
+
     protected function accumulate_messages(&$messages, $new) {
         if (is_array($new)) {
             $messages = array_merge($messages, $new);

mod/quiz/accessrule/accessrulebase.php

@@ -128,4 +128,39 @@ abstract class quiz_access_rule_base {
     public static function save_settings($quiz) {
         // By default do nothing.
     }
+
+    /**
+     * Return the bits of SQL needed to load all the settings from all the access
+     * plugins in one DB query. The easiest way to understand what you need to do
+     * here is probalby to read the code of {@link quiz_access_manager::load_settings()}.
+     *
+     * If you have some settings that cannot be loaded in this way, then you can
+     * use the {@link get_extra_settings()} method instead, but that has
+     * performance implications.
+     *
+     * @param int $quizid the id of the quiz we are loading settings for. This
+     *     can also be accessed as quiz.id in the SQL. (quiz is a table alisas for {quiz}.)
+     * @return array with three elements:
+     *     1. fields: any fields to add to the select list. These should be alised
+     *        if neccessary so that the field name starts the name of the plugin.
+     *     2. joins: any joins (should probably be LEFT JOINS) with other tables that
+     *        are needed.
+     *     3. params: array of placeholder values that are needed by the SQL. You must
+     *        used named placeholders, and the placeholder names should start with the
+     *        plugin name, to avoid collisions.
+     */
+    public static function get_settings_sql($quizid) {
+        return array('', '', array());
+    }
+
+    /**
+     * You can use this method to load any extra settings your plugin has that
+     * cannot be loaded efficiently with get_settings_sql().
+     * @param int $quizid the quiz id.
+     * @return array setting value name => value. The value names should all
+     *      start with the name of your plugin to avoid collisions.
+     */
+    public static function get_extra_settings($quizid) {
+        return array();
+    }
 }

mod/quiz/mod_form.php

@@ -452,6 +452,14 @@ class mod_quiz_mod_form extends moodleform_mod {
             $toform['quizpassword'] = $toform['password'];
             unset($toform['password']);
         }
+
+        // Load any settings belonging to the access rules.
+        if (!empty($toform['instance'])) {
+            $accesssettings = quiz_access_manager::load_settings($toform['instance']);
+            foreach ($accesssettings as $name => $value) {
+                $toform[$name] = $value;
+            }
+        }
     }
 
     public function validation($data, $files) {