<?
/*
Copyright (C) 2003  Andrew Chen (cacheit@andrewsw.com)

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA  02111-1307, USA.


A copy of this software may be available at http://www.andrewsw.com/products/
*/

class Cachable {
	function get($key) {
		/* subclasses should over-ride to return something
			based on the $key
		*/
		return $key;
	}
};

class CacheIt {

	var $cachePath;
	var $myCachable;
	var $maxCacheTime;

	/* cachableClass must be an instance of the class */
	/* theCachePath must have a trailing "/" */
	/* maxCacheTimeValue is given in seconds */
	function CacheIt($cachableClass,$theCachePath,$maxCacheTimeValue) {
		$this->myCachable = $cachableClass;
		$this->maxCacheTime = $maxCacheTimeValue;
		$this->cachePath = $theCachePath;
	}

	function get($key) {
		$nameOfFileWithCachedData = $this->cachePath . md5(serialize($key));
		if (file_exists($nameOfFileWithCachedData)&&(filectime($nameOfFileWithCachedData)>(time()-($this->maxCacheTime)))) {
			$fp = fopen($nameOfFileWithCachedData,"r");
			list($aKey,$aValue) = unserialize(fread($fp,filesize($nameOfFileWithCachedData)));
			fclose($fp);
			if ($key == $aKey) {
				return ($aValue);
			} else {
				return ($this->myCachable->get($key));
			};
		} else {
			if (file_exists($nameOfFileWithCachedData)) {
				unlink($nameOfFileWithCachedData);
			};
			$value = $this->myCachable->get($key);
			$this->set($key,$value);
			return $value;
		};
	}
	function set($key,$value) {
		$nameOfFileWithCachedData = $this->cachePath . md5(serialize($key));
		$fp = fopen($nameOfFileWithCachedData,"w");
		fwrite($fp,serialize(array($key,$value)));
		fclose($fp);
		return $value;
	}
};

?>