<?php
/***************************************************************/
/* PhpCache - a class for caching arbitrary data
Software License Agreement (BSD License)
Copyright (C) 2005-2007, Edward Eliot.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Edward Eliot nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission of Edward Eliot.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS" AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Updated by Neil Crosby for thetenwordreview.com
* Now allows a prefix to be given to the cached file's name.
* Also keeps cached data in memory for the script's duration so that
re-requesting it on the same page does not incur a reload of the file.
* Now allows CACHE_PATH to be set elsewhere.
/***************************************************************/
if ( !defined('CACHE_PATH') ) {
define('CACHE_PATH', $_SERVER['DOCUMENT_ROOT'].'/cache/');
}
class PhpCache {
var $sFile;
var $sFileLock;
var $iCacheTime;
var $sShortKey;
static $aCache = array();
/**
* @param $sPrefix Allows an extra string to be prepended to the
* MD5ed filename to allow for easy identification
* between cached types.
**/
function PhpCache($sKey, $iCacheTime, $sPrefix='') {
$this->sShortKey = $sPrefix.md5($sKey);
$this->sFile = CACHE_PATH.$this->sShortKey.".txt";
$this->sFileLock = "$this->sFile.lock";
$iCacheTime >= 0 ? $this->iCacheTime = $iCacheTime : $this->iCacheTime = 0;
}
function Check() {
if ( array_key_exists( $this->sShortKey, self::$aCache ) ) {
return true;
}
if (file_exists($this->sFileLock)) return true;
return (file_exists($this->sFile) && ($this->iCacheTime == -1 || time() - filemtime($this->sFile) <= $this->iCacheTime));
}
function Exists() {
return (array_key_exists( $this->sShortKey, self::$aCache )) || (file_exists($this->sFile) || file_exists($this->sFileLock));
}
function Set($vContents) {
if (!file_exists($this->sFileLock)) {
if (file_exists($this->sFile)) {
copy($this->sFile, $this->sFileLock);
}
$oFile = fopen($this->sFile, 'w');
fwrite($oFile, serialize($vContents));
fclose($oFile);
if (file_exists($this->sFileLock)) {
/*
* Suppress errors that come from unlinking the lock file.
* If a race condition has occurred and the lock file has
* already been deleted, that's okay.
*/
@unlink($this->sFileLock);
}
self::$aCache[$this->sShortKey] = $vContents;
return true;
}
return false;
}
function Get() {
if (array_key_exists( $this->sShortKey, self::$aCache )) {
return self::$aCache[$this->sShortKey];
} else if (file_exists($this->sFileLock)) {
$temp = unserialize(file_get_contents($this->sFileLock));
self::$aCache[$this->sShortKey] = $temp;
return $temp;
} else {
$temp = unserialize(file_get_contents($this->sFile));
self::$aCache[$this->sShortKey] = $temp;
return $temp;
}
}
function ReValidate() {
touch($this->sFile);
}
}
?>
