<?php

> /**

>  * Memory caching.
// security - hide paths
>  *
if (!defined('ADODB_DIR')) die();
>  * This file is part of ADOdb, a Database Abstraction Layer library for PHP.

>  *
global $ADODB_INCLUDED_MEMCACHE;
>  * @package ADOdb
$ADODB_INCLUDED_MEMCACHE = 1;
>  * @link https://adodb.org Project's web site and documentation

>  * @link https://github.com/ADOdb/ADOdb Source code and issue tracker
global $ADODB_INCLUDED_CSV;
>  *
if (empty($ADODB_INCLUDED_CSV)) include_once(ADODB_DIR.'/adodb-csvlib.inc.php');
>  * The ADOdb Library is dual-licensed, released under both the BSD 3-Clause

>  * and the GNU Lesser General Public Licence (LGPL) v2.1 or, at your option,
/*
>  * any later version. This means you can use it in proprietary products.

>  * See the LICENSE.md file distributed with this source code for details.
  @version   v5.21.0  2021-02-27
>  * @license BSD-3-Clause
  @copyright (c) 2000-2013 John Lim (jlim#natsoft.com). All rights reserved.
>  * @license LGPL-2.1-or-later
  @copyright (c) 2014      Damien Regad, Mark Newnham and the ADOdb community
>  *
  Released under both BSD license and Lesser GPL library license.
>  * @copyright 2000-2013 John Lim
  Whenever there is any discrepancy between the two licenses,
>  * @copyright 2014 Damien Regad, Mark Newnham and the ADOdb community
  the BSD license will take precedence. See License.txt.
>  */



< 
< /*
< 
<   @version   v5.21.0  2021-02-27
<   @copyright (c) 2000-2013 John Lim (jlim#natsoft.com). All rights reserved.
<   @copyright (c) 2014      Damien Regad, Mark Newnham and the ADOdb community
<   Released under both BSD license and Lesser GPL library license.
<   Whenever there is any discrepancy between the two licenses,
<   the BSD license will take precedence. See License.txt.
<   Set tabs to 4 for best viewing.
< 
<   Latest version is available at https://adodb.org/
< 
< Usage:
< 
< $db = NewADOConnection($driver);
< $db->memCache = true; /// should we use memCache instead of caching in files
< $db->memCacheHost = array($ip1, $ip2, $ip3);
< $db->memCachePort = 11211; /// this is default memCache port
< $db->memCacheCompress = false; /// Use 'true' to store the item compressed (uses zlib)
<                                /// Note; compression is not supported w/the memcached library
< 
< $db->Connect(...);
< $db->CacheExecute($sql);
< 
<   Notes; The memcache class is shared by all connections, is created during the first call to Connect/PConnect.
<          We'll look for both the memcache library (https://pecl.php.net/package/memcache) and the  memcached
<          library (https://pecl.php.net/package/memcached). If both exist, the memcache library will be used.
< 
<   Class instance is stored in $ADODB_CACHE
< */


		//-----------------------------
		// memcache specific variables

		var $hosts;	// array of hosts
		var $port = 11211;
		var $compress = false; // memcache compression with zlib

		var $_connected = false;
		var $_memcache = false;

		function __construct(&$obj)
		{
			$this->hosts = $obj->memCacheHost;
			$this->port = $obj->memCachePort;
			$this->compress = $obj->memCacheCompress;
		}

		// implement as lazy connection. The connection only occurs on CacheExecute call
		function connect(&$err)
		{
			// do we have memcache or memcached?
			if (class_exists('Memcache')) {
				$this->library='Memcache';
				$memcache = new MemCache;
			} elseif (class_exists('Memcached')) {
				$this->library='Memcached';
				$memcache = new MemCached;
			} else {
				$err = 'Neither the Memcache nor Memcached PECL extensions were found!';
				return false;
			}

			if (!is_array($this->hosts)) $this->hosts = array($this->hosts);

			$failcnt = 0;
			foreach($this->hosts as $host) {
				if (!@$memcache->addServer($host,$this->port)) {
					$failcnt += 1;
				}
			}
			if ($failcnt == sizeof($this->hosts)) {
				$err = 'Can\'t connect to any memcache server';
				return false;
			}
			$this->_connected = true;
			$this->_memcache = $memcache;
			return true;
		}

		// returns true or false. true if successful save
		function writecache($filename, $contents, $debug, $secs2cache)
		{
			if (!$this->_connected) {
				$err = '';
				if (!$this->connect($err) && $debug) ADOConnection::outp($err);
			}
			if (!$this->_memcache) return false;

			$failed=false;
			switch ($this->library) {
				case 'Memcache':
					if (!$this->_memcache->set($filename, $contents, $this->compress ? MEMCACHE_COMPRESSED : 0, $secs2cache)) {
						$failed=true;
					}
					break;
				case 'Memcached':
					if (!$this->_memcache->set($filename, $contents, $secs2cache)) {
						$failed=true;
					}
					break;
				default:
					$failed=true;
					break;
			}

			if($failed) {
				if ($debug) ADOConnection::outp(" Failed to save data at the memcache server!<br>\n");
				return false;
			}

			return true;
		}

		// returns a recordset
		function readcache($filename, &$err, $secs2cache, $rsClass)
		{
			$false = false;
			if (!$this->_connected) $this->connect($err);
			if (!$this->_memcache) return $false;

			$rs = $this->_memcache->get($filename);
			if (!$rs) {
				$err = 'Item with such key doesn\'t exist on the memcache server.';
				return $false;
			}

			// hack, should actually use _csv2rs
			$rs = explode("\n", $rs);
            unset($rs[0]);
            $rs = join("\n", $rs);
 			$rs = unserialize($rs);
			if (! is_object($rs)) {
				$err = 'Unable to unserialize $rs';
				return $false;
			}
			if ($rs->timeCreated == 0) return $rs; // apparently have been reports that timeCreated was set to 0 somewhere

			$tdiff = intval($rs->timeCreated+$secs2cache - time());
			if ($tdiff <= 2) {
				switch($tdiff) {
					case 2:
						if ((rand() & 15) == 0) {
							$err = "Timeout 2";
							return $false;
						}
						break;
					case 1:
						if ((rand() & 3) == 0) {
							$err = "Timeout 1";
							return $false;
						}
						break;
					default:
						$err = "Timeout 0";
						return $false;
				}
			}
			return $rs;
		}

		function flushall($debug=false)
		{
			if (!$this->_connected) {
				$err = '';
				if (!$this->connect($err) && $debug) ADOConnection::outp($err);
			}
			if (!$this->_memcache) return false;

			$del = $this->_memcache->flush();

			if ($debug)
				if (!$del) ADOConnection::outp("flushall: failed!<br>\n");
				else ADOConnection::outp("flushall: succeeded!<br>\n");

			return $del;
		}

		function flushcache($filename, $debug=false)
		{
			if (!$this->_connected) {
  				$err = '';
  				if (!$this->connect($err) && $debug) ADOConnection::outp($err);
			}
			if (!$this->_memcache) return false;

			$del = $this->_memcache->delete($filename);

			if ($debug)
				if (!$del) ADOConnection::outp("flushcache: $key entry doesn't exist on memcache server!<br>\n");
				else ADOConnection::outp("flushcache: $key entry flushed from memcache server!<br>\n");

			return $del;
		}

		// not used for memcache
		function createdir($dir, $hash)
		{
			return true;
		}
	}