Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle 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.

//

// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Cache data source for the quiz overrides.

 *

 * @package   mod_quiz

 * @copyright 2021 Shamim Rezaie <shamim@moodle.com>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

declare(strict_types=1);

namespace mod_quiz\cache;

use core_cache\data_source_interface;

use core_cache\definition;

/**

 * Class quiz_overrides

 *

 * @package   mod_quiz

 * @copyright 2021 Shamim Rezaie <shamim@moodle.com>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class overrides implements data_source_interface {

    /** @var overrides the singleton instance of this class. */

    protected static $instance = null;

    /**

     * Returns an instance of the data source class that the cache can use for loading data using the other methods

     * specified by this interface.

     *

     * @param definition $definition

     * @return overrides

     */

    public static function get_instance_for_cache(definition $definition): overrides {

        if (is_null(self::$instance)) {

            self::$instance = new overrides();

        }

        return self::$instance;

    }

    /**

     * Loads the data for the key provided ready formatted for caching.

     *

     * @param string|int $key The key to load.

     * @return mixed What ever data should be returned, or false if it can't be loaded.

     * @throws \coding_exception

     */

    public function load_for_cache($key) {

        global $DB;

        // Ignore getting data if this is a cache invalidation - {@see \core_cache\helper::purge_by_event()}.

        if ($key == 'lastinvalidation') {

            return null;

        }

        [$quizid, $ug, $ugid] = explode('_', $key);

        $quizid = (int) $quizid;

        switch ($ug) {

            case 'u':

                $userid = (int) $ugid;

                $override = $DB->get_record(

                    'quiz_overrides',

                    ['quiz' => $quizid, 'userid' => $userid],

                    'timeopen, timeclose, timelimit, attempts, password'

                );

                break;

            case 'g':

                $groupid = (int) $ugid;

                $override = $DB->get_record(

                    'quiz_overrides',

                    ['quiz' => $quizid, 'groupid' => $groupid],

                    'timeopen, timeclose, timelimit, attempts, password'

                );

                break;

            default:

                throw new \coding_exception('Invalid cache key');

        }

        // Return null instead of false, because false will not be cached.

        return $override ?: null;

    }

    /**

     * Loads several keys for the cache.

     *

     * @param array $keys An array of keys each of which will be string|int.

     * @return array An array of matching data items.

     */

    public function load_many_for_cache(array $keys) {

        $results = [];

        foreach ($keys as $key) {

            $results[] = $this->load_for_cache($key);

        }

        return $results;

    }

}