Tasks cron

<?php
if (!class_exists('tasks')) include '/home/way_to_module/tasks.inc';

$lock_file='/home/user/tmpdir/lockfile.name';

if (file_exists($lock_file))
{
    if (filemtime($lock_file)>(time()-10800)) exit;
}
$lock_fh=fopen($lock_file,'w');

$starttime=time();
$tasks=tasks::get_tasks();
if (!empty($tasks))
{
    $q=array();
    foreach ($tasks as $task) $q[$task->priority][]=$task;
    ksort($q);
    foreach ($q as $priority)
    {
        foreach ($priority as $task)
        {
            tasks::execute($task);
            if ((time()-$starttime)>100) break;
        }
        if ((time()-$starttime)>100) break;
    }
}
fclose($lock_fh);
unlink($lock_file);
?>