[mxbb-commits] core/includes/lock db.php, NONE, 1.1 flock.php, NONE, 1.1

[Florin C B. <ory...@us...>]

Update of /cvsroot/mxbb/core/includes/lock
In directory sfp-cvs-1.v30.ch3.sourceforge.com:/tmp/cvs-serv25562/lock

Added Files:
	db.php flock.php 
Log Message:


--- NEW FILE: flock.php ---
<?php
/**
*
* @package MXP3
* @copyright (c) 2012 phpBB Group
* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
*
*/

/**
* @ignore
*/
if (!defined('IN_PORTAL'))
{
	exit;
}

/**
* File locking class
* @package MXP3
*/
class mx_lock_flock
{
	/**
	* Path to the file to which access is controlled
	*
	* @var string
	*/
	private $path;

	/**
	* File pointer for the lock file
	* @var string
	*/
	private $lock_fp;

	/**
	* Constructor.
	*
	* You have to call acquire() to actually acquire the lock.
	*
	* @param	string	$path	Path to the file to which access is controlled
	*/
	public function __construct($path)
	{
		$this->path = $path;
		$this->lock_fp = null;
	}

	/**
	* Tries to acquire the lock.
	*
	* If the lock is already held by another process, this call will block
	* until the other process releases the lock. If a lock is acquired and
	* is not released before script finishes but the process continues to
	* live (apache/fastcgi) then subsequent processes trying to acquire
	* the same lock will be blocked forever.
	*
	* If the lock is already held by the same process via another instance
	* of this class, this call will block forever.
	*
	* If flock function is disabled in php or fails to work, lock
	* acquisition will fail and false will be returned.
	*
	* @return	bool			true if lock was acquired
	*							false otherwise
	*/
	public function acquire()
	{
		if ($this->lock_fp)
		{
			return false;
		}

		// For systems that can't have two processes opening
		// one file for writing simultaneously
		if (file_exists($this->path . '.lock'))
		{
			$mode = 'rb';
		}
		else
		{
			$mode = 'wb';
		}

		$this->lock_fp = @fopen($this->path . '.lock', $mode);

		if ($mode == 'wb')
		{
			if (!$this->lock_fp)
			{
				// Two processes may attempt to create lock file at the same time.
				// Have the losing process try opening the lock file again for reading
				// on the assumption that the winning process created it
				$mode = 'rb';
				$this->lock_fp = @fopen($this->path . '.lock', $mode);
			}
			else
			{
				// Only need to set mode when the lock file is written
				@chmod($this->path . '.lock', 0666);
			}
		}

		if ($this->lock_fp)
		{
			@flock($this->lock_fp, LOCK_EX);
		}

		return (bool) $this->lock_fp;
	}

	/**
	* Does this process own the lock?
	*
	* @return	bool			true if lock is owned
	*							false otherwise
	*/
	public function owns_lock()
	{
		return (bool) $this->lock_fp;
	}

	/**
	* 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 ($this->lock_fp)
		{
			@flock($this->lock_fp, LOCK_UN);
			fclose($this->lock_fp);
			$this->lock_fp = null;
		}
	}
}

--- NEW FILE: db.php ---
<?php
/**
*
* @package MXP3
* @copyright (c) 2010 phpBB Group
* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
*
*/

/**
* @ignore
*/
if (!defined('IN_PORTAL'))
{
	exit;
}

/**
* Database locking class
* @package MXP3
*/
class mx_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 MXP configuration
	* @var phpbb_config
	*/
	private $portal_config;

	/**
	* A database connection
	* @var mx_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, mx_config $portal_config, mx_db_driver $db)
	{
		$this->portal_config_name = $config_name;
		$this->portal_config = $portal_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($this->portal_config[$this->portal_config_name]))
		{
			$this->portal_config->set($this->portal_config_name, '0', false);
		}
		$lock_value = $this->portal_config[$this->portal_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 = $this->portal_config->set_atomic($this->portal_config_name, $lock_value, $this->unique_id, false);

		return $this->locked;
	}

	/**
	* Does this process own the lock?
	*
	* @return	bool			true if lock is owned
	*							false otherwise
	*/
	public function owns_lock()
	{
		return (bool) $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)
		{
			$this->portal_config->set_atomic($this->portal_config_name, $this->unique_id, '0', false);
			$this->locked = false;
		}
	}
}