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mirror of https://github.com/phpbb/phpbb.git synced 2025-02-25 04:23:38 +01:00
Oleg Pudeyev 26fd70d9cd Merge remote-tracking branch 'upstream/develop' into ticket/11015
* upstream/develop: (196 commits)
  [ticket/11219] Coding guidelines and naming consistency changes
  [ticket/10841] Revert more whitespace changes.
  [ticket/10841] Revert whitespace changes.
  [ticket/10841] adding space after if
  [ticket/10841] removing unnecessary spacing
  [ticket/10841] changing affectedrows check to COUNT in sql
  [ticket/10841] Modifying style and language selectors in UCP
  [ticket/11247] Fix wrong property reference in flock class.
  [ticket/10602] Avoid a race condition.
  [ticket/10602] Use last_queue_run for its intended purpose.
  [ticket/10716] Collect standard error from executed php process.
  [ticket/10716] Skip test if php is not in PATH.
  [ticket/10716] Exclude our dependencies from linting.
  [ticket/10103] New and improved wording.
  [ticket/10716] Only lint on php 5.3+.
  [ticket/10103] Assert with messages.
  [ticket/10103] assertLessThan/assertGreaterThan.
  [ticket/10103] Inline assignment is bad?
  [ticket/10103] $rv had too few characters.
  [ticket/10103] Correct flock class documentation.
  ...

Conflicts:
	phpBB/includes/functions.php
	tests/cache/cache_test.php
2012-12-06 21:49:24 -05:00

139 lines
2.8 KiB
PHP

<?php
/**
*
* @package phpBB3
* @copyright (c) 2010 phpBB Group
* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
*
*/
/**
* @ignore
*/
if (!defined('IN_PHPBB'))
{
exit;
}
/**
* Database locking class
* @package phpBB3
*/
class phpbb_lock_db
{
/**
* Name of the config variable this lock uses
* @var string
*/
private $config_name;
/**
* Unique identifier for this lock.
*
* @var string
*/
private $unique_id;
/**
* Stores the state of this lock
* @var bool
*/
private $locked;
/**
* The phpBB configuration
* @var phpbb_config
*/
private $config;
/**
* A database connection
* @var phpbb_db_driver
*/
private $db;
/**
* Creates a named released instance of the lock.
*
* You have to call acquire() to actually create the lock.
*
* @param string $config_name A config variable to be used for locking
* @param array $config The phpBB configuration
* @param phpbb_db_driver $db A database connection
*/
public function __construct($config_name, phpbb_config $config, phpbb_db_driver $db)
{
$this->config_name = $config_name;
$this->config = $config;
$this->db = $db;
}
/**
* Tries to acquire the lock by updating
* the configuration variable in the database.
*
* As a lock may only be held by one process at a time, lock
* acquisition may fail if another process is holding the lock
* or if another process obtained the lock but never released it.
* Locks are forcibly released after a timeout of 1 hour.
*
* @return bool true if lock was acquired
* false otherwise
*/
public function acquire()
{
if ($this->locked)
{
return false;
}
if (!isset($this->config[$this->config_name]))
{
$this->config->set($this->config_name, '0', false);
}
$lock_value = $this->config[$this->config_name];
// make sure lock cannot be acquired by multiple processes
if ($lock_value)
{
// if the other process is running more than an hour already we have to assume it
// aborted without cleaning the lock
$time = explode(' ', $lock_value);
$time = $time[0];
if ($time + 3600 >= time())
{
return false;
}
}
$this->unique_id = time() . ' ' . unique_id();
// try to update the config value, if it was already modified by another
// process we failed to acquire the lock.
$this->locked = $this->config->set_atomic($this->config_name, $lock_value, $this->unique_id, false);
return $this->locked;
}
/**
* Releases the lock.
*
* The lock must have been previously obtained, that is, acquire() call
* was issued and returned true.
*
* Note: Attempting to release a lock that is already released,
* that is, calling release() multiple times, is harmless.
*
* @return null
*/
public function release()
{
if ($this->locked)
{
$this->config->set_atomic($this->config_name, $this->unique_id, '0', false);
$this->locked = false;
}
}
}