friendica/src/Core/Lock/DatabaseLockDriver.php

110 lines
2.3 KiB
PHP

<?php
namespace Friendica\Core\Lock;
use Friendica\Core\Cache;
use Friendica\Database\DBA;
use Friendica\Util\DateTimeFormat;
/**
* Locking driver that stores the locks in the database
*/
class DatabaseLockDriver extends AbstractLockDriver
{
/**
* The current ID of the process
*
* @var int
*/
private $pid;
/**
* @param null|int $pid The Id of the current process (null means determine automatically)
*/
public function __construct($pid = null)
{
$this->pid = isset($pid) ? $pid : getmypid();
}
/**
* (@inheritdoc)
*/
public function acquireLock($key, $timeout = 120, $ttl = Cache::FIVE_MINUTES)
{
$got_lock = false;
$start = time();
do {
DBA::lock('locks');
$lock = DBA::selectFirst('locks', ['locked', 'pid'], ['`name` = ? AND `expires` >= ?', $key, DateTimeFormat::utcNow()]);
if (DBA::isResult($lock)) {
if ($lock['locked']) {
// We want to lock something that was already locked by us? So we got the lock.
if ($lock['pid'] == $this->pid) {
$got_lock = true;
}
}
if (!$lock['locked']) {
DBA::update('locks', ['locked' => true, 'pid' => $this->pid, 'expires' => DateTimeFormat::utc('now + ' . $ttl . 'seconds')], ['name' => $key]);
$got_lock = true;
}
} else {
DBA::insert('locks', ['name' => $key, 'locked' => true, 'pid' => $this->pid, 'expires' => DateTimeFormat::utc('now + ' . $ttl . 'seconds')]);
$got_lock = true;
$this->markAcquire($key);
}
DBA::unlock();
if (!$got_lock && ($timeout > 0)) {
usleep(rand(100000, 2000000));
}
} while (!$got_lock && ((time() - $start) < $timeout));
return $got_lock;
}
/**
* (@inheritdoc)
*/
public function releaseLock($key, $force = false)
{
if ($force) {
$where = ['name' => $key];
} else {
$where = ['name' => $key, 'pid' => $this->pid];
}
DBA::delete('locks', $where);
$this->markRelease($key);
return;
}
/**
* (@inheritdoc)
*/
public function releaseAll()
{
DBA::delete('locks', ['pid' => $this->pid]);
$this->acquiredLocks = [];
}
/**
* (@inheritdoc)
*/
public function isLocked($key)
{
$lock = DBA::selectFirst('locks', ['locked'], ['`name` = ? AND `expires` >= ?', $key, DateTimeFormat::utcNow()]);
if (DBA::isResult($lock)) {
return $lock['locked'] !== false;
} else {
return false;
}
}
}