From 0f9b3bcc27e7daf7d605a7a38310a8f62b9a76e8 Mon Sep 17 00:00:00 2001
From: Oleg Pudeyev <oleg@bsdpower.com>
Date: Sat, 17 Apr 2010 03:13:30 -0400
Subject: [feature/system-cron] Refactored cron task naming, loading and
 running.

PHPBB3-9596
---
 phpBB/includes/cron/cron_lock.php | 75 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 phpBB/includes/cron/cron_lock.php

(limited to 'phpBB/includes/cron/cron_lock.php')

diff --git a/phpBB/includes/cron/cron_lock.php b/phpBB/includes/cron/cron_lock.php
new file mode 100644
index 0000000000..1046d62da4
--- /dev/null
+++ b/phpBB/includes/cron/cron_lock.php
@@ -0,0 +1,75 @@
+<?php
+/**
+*
+* @package phpBB3
+* @version $Id$
+* @copyright (c) 2010 phpBB Group
+* @license http://opensource.org/licenses/gpl-license.php GNU Public License
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+/**
+* Cron lock class
+* @package phpBB3
+*/
+class cron_lock
+{
+	private $cron_id;
+
+	function lock()
+	{
+		global $config, $db;
+
+		if (!isset($config['cron_lock']))
+		{
+			set_config('cron_lock', '0', true);
+		}
+
+		// make sure cron doesn't run multiple times in parallel
+		if ($config['cron_lock'])
+		{
+			// if the other process is running more than an hour already we have to assume it
+			// aborted without cleaning the lock
+			$time = explode(' ', $config['cron_lock']);
+			$time = $time[0];
+
+			if ($time + 3600 >= time())
+			{
+				return false;
+			}
+		}
+
+		$this->cron_id = time() . ' ' . unique_id();
+
+		$sql = 'UPDATE ' . CONFIG_TABLE . "
+			SET config_value = '" . $db->sql_escape($this->cron_id) . "'
+			WHERE config_name = 'cron_lock' AND config_value = '" . $db->sql_escape($config['cron_lock']) . "'";
+		$db->sql_query($sql);
+
+		// another cron process altered the table between script start and UPDATE query so exit
+		if ($db->sql_affectedrows() != 1)
+		{
+			return false;
+		}
+
+		return true;
+	}
+
+	function unlock()
+	{
+		global $db;
+
+		$sql = 'UPDATE ' . CONFIG_TABLE . "
+			SET config_value = '0'
+			WHERE config_name = 'cron_lock' AND config_value = '" . $db->sql_escape($this->cron_id) . "'";
+		$db->sql_query($sql);
+	}
+}
-- 
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