<?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/>.
namespace core\lock;
use core\progress\base;
/**
* Lock utilities.
*
* @package core
* @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
* @author Mark Johnson <mark.johnson@catalyst-eu.net>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class lock_utils {
/**
* Start a progress bar and attempt to get a lock, updating the bar until a lock is achieved.
*
* This will make multiple attempts at getting the lock using a short timeout set by $progressupdatetime. After
* each failed attempt, it will update the progress bar and try again, until $timeout is reached.
*
* @param lock_factory $lockfactory The factory to use to get the lock
* @param string $resource The resource key we will try to get a lock on
* @param base $progress The progress bar
* @param int $timeout The maximum time in seconds to wait for a lock
* @param string $message Optional message to display on the progress bar
* @param int $progressupdatetime The number of seconds to wait for each lock attempt before updating the progress bar.
* @param int $maxlifetime The maxlifetime to set on the lock, if supported.
* @return lock|false A lock if successful, or false if the timeout expires.
* @throws \coding_exception
*/
public static function wait_for_lock_with_progress(
lock_factory $lockfactory,
string $resource,
\core\progress\base $progress,
int $timeout,
string $message = '',
int $progressupdatetime = 10,
< int $maxlifetime = DAYSECS
> int $maxlifetime = DAYSECS,
) {
if ($progressupdatetime < 1) {
throw new \invalid_parameter_exception('Progress bar cannot update more than once per second. ' .
'$progressupdate time must be at least 1.');
}
if ($progressupdatetime > $timeout) {
throw new \invalid_parameter_exception('$timeout must be greater than $progressupdatetime.');
}
$lockattempts = 0;
$maxattempts = $timeout / $progressupdatetime;
$lock = false;
$progress->start_progress($message);
while (!$lock && $lockattempts < $maxattempts) {
$lock = $lockfactory->get_lock($resource, $progressupdatetime, $maxlifetime);
if (!$lock) {
$progress->progress();
$lockattempts++;
}
}
$progress->end_progress();
return $lock;
}
}