Source for file lib_cache.php

<?php
/*
 * Lokorin.com
 * Copyright 2004-2006
 * Licensed under the GNU LGPL. See COPYING for full terms.
 */
/**
 * A library that contains functions and classes related to caching contents
 * in files. Contents should be cached this way if it is rarely updated, only
 * wanted in one specific form and often read.
 * @author Andreas Launila
 * @version $Revision: 1.1 $
 * @package com.lokorin.lokorin.lib
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 */
 
/**
 * Checks if there is a cache related to the specified unique identifier.
 * @param string $uniqueId The unique identifier that will be checked for
 *          connections to existing cached files.
 * @return boolean True if a cached file exists for the identifier, false
 *          otherwise.
 * @access public
 */
function cacheExists($uniqueId) {
    return file_exists(getCacheFile($uniqueId));
}
 
/**
 * Gets the cache associated with the specified unique identifier.
 * @param string $uniqueId The unique identifier that identifies the cache
 *          that should be retrieved. This is the unique identifier that was given
 *          when writing the cache.
 * @return string The specified cache contents.
 * @throws IllegalArgumentException If there is no cache associated with the
 *          specified identifier.
 * @access public
 */
function getCache($uniqueId) {
    $cacheFile = getCacheFile($uniqueId);
    if(!file_exists($cacheFile)) {
        throw new IllegalArgumentException("No cache exists for the specified ".
                "identifier (".$uniqueId.").");
    }
    return file_get_contents($cacheFile);
}
 
/**
 * Writes a specified cache contents and associates it with the specified
 * unique identifier. This function will overwrite any existing cache with the
 * same identifier.
 * @param string $uniqueId The unique identifier that should identify the
 *          cache.
 * @param string $contents The contents that should be cached.
 * @access public
 */
function writeCache($uniqueId, $contents) {
    file_put_contents(getCacheFile($uniqueId), $contents);
}
 
/**
 * Deletes the cache with the specified unique identifier.
 * @param string $uniqueId The unique identifier that identifies the cache that
 *          should be deleted.
 * @return boolean True if the cache was successfully deleted, false otherwise.
 * @access public
 */
function deleteCache($uniqueId) {
    return unlink(getCacheFile($uniqueId));
}
 
/**
 * Gets the absolute path of the file connected to the specified identifier.
 * @param string $identifier The identifier for which the file name should be
 *          retrieved.
 * @access private
 */
function getCacheFile($identifier) {
    return DOC_ROOT.FOLDER_CACHE.md5($identifier).'.chc';
}
 
/**
 * Deletes all contents that is currently cached.
 */
function deleteAllCachedContents() {
    $fileList = array();
    $folder = DOC_ROOT.FOLDER_CACHE;
    if($dir = @opendir($folder)) {
        while(($file = readdir($dir)) !== false) {
            if(substr($file, -4) == '.chc') {
                unlink($folder.$file);
            }
        }
        closedir($dir);
    }
}
 
?>