acm_db.php

<?php
/**
*
* @package acm
* @version $Id$
* @copyright (c) 2005, 2009 phpBB Group
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/

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

define('CACHE_TABLE', $table_prefix . 'cache');
define('PHPBB_ACM_DB_EXISTS', 1);
define('PHPBB_ACM_DB_STALE', 2);
define('PHPBB_ACM_DB_READY', 4);

/*
DROP TABLE IF EXISTS phpbb_cache;

CREATE TABLE phpbb_cache (
   var_name VARCHAR(255) NOT NULL,
   var_data MEDIUMTEXT NOT NULL,
   var_expires int(11) NOT NULL,
   var_global tinyint(1) NOT NULL,
   PRIMARY KEY (var_name),
   KEY var_expires (var_expires),
   KEY var_global (var_global)
) CHARACTER SET utf8 COLLATE utf8_bin;
*/

/**
* ACM for caching in the database
* @package acm
*/
class acm
{
	var $cache_dir;

	var $vars;
	var $states;
	var $ttls;

	function acm()
	{
		global $phpbb_root_path;

		$this->cache_dir = $phpbb_root_path . 'cache/';
	}

	function load($var_name = '')
	{
		global $db;

		$this->vars = $this->states = $this->ttls = array();

		$sql_extra = ($var_name) ? " OR var_name = '" . $db->sql_escape($var_name) . "'" : '';

		$sql = 'SELECT var_name, var_data
			FROM ' . CACHE_TABLE . '
			WHERE var_expires > ' . time() . "
				AND (var_global = 1$sql_extra)";
		$result = $db->sql_query($sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$this->vars[$row['var_name']] = $row['var_data'];
			$this->states[$row['var_name']] = PHPBB_ACM_DB_EXISTS;
		}
		$db->sql_freeresult($result);
	}

	function unload()
	{
		$this->save();
		unset($this->vars);
	}

	function purge()
	{
		global $db;

		// Purge all phpbb cache files
		$dir = @opendir($this->cache_dir);

		if (!$dir)
		{
			return;
		}

		while (($entry = readdir($dir)) !== false)
		{
			if (strpos($entry, 'ctpl_') !== 0 && strpos($entry, 'tpl_') !== 0)
			{
				continue;
			}

			$this->remove_file($this->cache_dir . $entry);
		}
		closedir($dir);

		// Quicker than truncate on small tables
		$sql = 'DELETE FROM ' . CACHE_TABLE;

		$db->sql_query($sql);

		foreach ($this->states as $var_name => $void)
		{
			$this->states[$var_name] = 0;
		}

		$this->vars = $this->ttls = array();
	}

	function save()
	{
		global $db;

		$delete = $insert = $update = array();

		$time = time();

		foreach ($this->states as $var_name => $state)
		{
			if (!($state & PHPBB_ACM_DB_STALE))
			{
				// Skip anything that is not stale
				continue;
			}

			if (!($state & PHPBB_ACM_DB_READY))
			{
				// If the var is not ready to use and is stale
				// it must have been deleted.
				$delete[] = $var_name;
			}
			else
			{
				if ($state & PHPBB_ACM_DB_EXISTS)
				{
					// Ready, existing, and stale must need updating
					$array = 'update';
				}
				else
				{
					$array = 'insert';
				}

				${$array}[$var_name] = array(
					'var_name'		=> $var_name,
					'var_data'		=> serialize($this->vars[$var_name]),
					'var_expires'	=> $this->ttls[$var_name] + $time,
					'var_global'	=> ($var_name[0] == '_' ? false : true),
				);
			}
		}

		if (empty($delete) && empty($update) && empty($insert))
		{
			return;
		}

		if (!empty($delete) || !empty($update))
		{
			$sql = 'DELETE FROM ' . CACHE_TABLE . '
				WHERE ' . $db->sql_in_set('var_name', array_merge($delete, array_keys($update)));

			// We only want to update the entries we really want to delete
			if (function_exists('array_combine'))
			{
				$this->states = array_merge($this->states, array_combine($delete, array_fill(0, sizeof($delete), 0)));
			}
			else
			{
				foreach ($delete as $var_name)
				{
					$this->states[$var_name] = 0;
				}
			}

			unset($delete);
		}

		if (!empty($insert) || !empty($update))
		{
			$insert = array_merge($insert, $update);

			$db->sql_multi_insert(CACHE_TABLE, array_values($insert));

			if (function_exists('array_combine'))
			{
				$this->states = array_merge($this->states, array_combine(array_keys($insert), array_fill(0, sizeof($insert), PHPBB_ACM_DB_READY | PHPBB_ACM_DB_EXISTS)));
			}
			else
			{
				foreach (array_keys($insert) as $var_name)
				{
					$this->states[$var_name] = PHPBB_ACM_DB_READY | PHPBB_ACM_DB_EXISTS;
				}
			}

			unset($insert, $update);
		}
	}

	function tidy()
	{
		global $db;

		$sql = 'DELETE FROM ' . CACHE_TABLE . '
			WHERE var_expires < ' . time();
		$db->sql_query($sql);

		set_config('cache_last_gc', time(), true);
	}

	function get($var_name)
	{
		if (!is_array($this->vars))
		{
			if ($var_name[0] == '_')
			{
				$this->load($var_name);
			}
			else
			{
				$this->load();
			}
		}

		if ($var_name[0] == '_' && !isset($this->states[$var_name]))
		{
			// Local, not known request it
			global $db;

			$sql = 'SELECT var_data
				FROM ' . CACHE_TABLE . "
				WHERE var_name = '" . $db->sql_escape($var_name) . "'
					AND var_expires > " . time();
			$result = $db->sql_query($sql);

			if ($row = $db->sql_fetchrow($result))
			{
				$this->vars[$var_name] = $row['var_data'];
				$this->states[$var_name] = PHPBB_ACM_DB_EXISTS;
			}
			else
			{
				$this->states[$var_name] = 0;
			}
			$db->sql_freeresult($result);
		}

		if ($this->_exists($var_name))
		{
			if (!($this->states[$var_name] & PHPBB_ACM_DB_READY))
			{
				$this->vars[$var_name] = unserialize($this->vars[$var_name]);
				$this->states[$var_name] |= PHPBB_ACM_DB_READY;
			}

			return $this->vars[$var_name];
		}
		else
		{
			return false;
		}
	}

	function put($var_name, $var_data, $ttl = 31536000)
	{
		if (!is_array($this->vars))
		{
			$this->load();
		}

		if (!isset($this->states[$var_name]))
		{
			$this->states[$var_name] = 0;
		}

		$this->vars[$var_name] = $var_data;

		$this->states[$var_name] |= PHPBB_ACM_DB_READY | PHPBB_ACM_DB_STALE;
		$this->ttls[$var_name] = $ttl;
	}

	function destroy($var_name)
	{
		if ($var_name == 'sql')
		{
			// We don't support SQL caching
			return;
		}

		if (!is_array($this->vars))
		{
			$this->load();
		}

		unset($this->vars[$var_name]);

		$this->states[$var_name] = ($this->states[$var_name] ^ PHPBB_ACM_DB_READY) | PHPBB_ACM_DB_STALE;
	}

	function _exists($var_name)
	{
		return (isset($this->vars[$var_name])) ? true : false;
	}

	/**
	* Removes/unlinks file
	*/
	function remove_file($filename, $check = false)
	{
		if ($check && !@is_writable($this->cache_dir))
		{
			// E_USER_ERROR - not using language entry - intended.
			trigger_error('Unable to remove files within ' . $this->cache_dir . '. Please check directory permissions.', E_USER_ERROR);
		}

		return @unlink($filename);
	}
}