php 无限级缓存的类的扩展

代码如下:
<?php
/**
* 功能: 根据条件建立分类缓存减少类别使用
* 创建日期:Thu May 31 15:55:11 CST 2007
* 最后更新:
* 作者: sanshi <sanshi0815@tom.com>
*/

class treeCache
{
var $tableName = "index_category"; //表名
var $where = "1"; //where条件
var $pidStr ="i_c_pid"; //pid 的字段名
var $tempCode = array(); //生成文件的数组
var $pid = '0'; //pid的初始值
var $db ; //数据库句柄
var $idStr="i_c_id"; //取得的数据id
var $title = "i_c_cn"; //名字字段
var $createArrayName = "treeCache"; //建立的数组名字
var $createFileName =""; //建立文件的名字
var $appendArr = array(); //附加的属性，需要字段名与数据里的名对应
var $is_utf8 = false;
function treeCache()
{
}
function set($db)
{
$this->db = $db;
$this->tempCode[] = "<?php";
}
//取得所有的一级
function getRootID()
{
$sql = "SELECT {$this->idStr} FROM {$this->tableName} WHERE
{$this->pidStr}='{$this->pid}' AND {$this->where} ";
//exit($sql);
$result = $this->db->select($sql);
$temp = array();
foreach ($result as $r)
{
$temp[]=$r["{$this->idStr}"];
}
$this->tempCode[] = "/${$this->createArrayName}['root']='".implode(',',$temp)."';";
//print_r($temp);
return $temp;
}
//取得子id
function getChildren($pid)
{
$sql = "SELECT {$this->idStr} FROM {$this->tableName} WHERE
{$this->pidStr}='{$pid}' AND {$this->where} ";
$result = $this->db->select($sql);
$temp = array();
foreach ($result as $r)
{
$temp[]=$r["{$this->idStr}"];
}
return $temp;
}
//取得夫id
function getParent($cid)
{
$sql = "SELECT {$this->pidStr} FROM {$this->tableName} WHERE
{$this->idStr}='{$cid}' AND {$this->where} ";
$result = $this->db->select($sql);
//print_r($result);exit();
return $result[0]["{$this->pidStr}"];
}
//取得上级的id
function getPidStr($cid,$pidStr="")
{
$pid=$this->getParent($cid);
$temp = array();
while ($pid!=$this->pid && !emptyempty($pid)) {
$temp[] = $pid;
$pid=$this->getParent($pid);
}
//print_r($temp);
return implode(',',$temp);
}
//取得深度
function getDepth($cid,$depth=0)
{
$pid=$this->getParent($cid);
$depth++;
if( $pid != $this->pid && !emptyempty($pid))
$depth = $this->getDepth($pid,$depth);
return $depth;
}
//建立文件
function make()
{
if(emptyempty($this->createFileName))
$this->createFileName = "{$this->createArrayName}.data.php";

$rootArr = $this->getRootID();
$selectF = "{$this->idStr},{$this->title},{$this->pidStr}";
foreach ($this->appendArr as $app)
{
if(emptyempty($app)) continue;
$selectF .=",{$app}";
}
$sql = "SELECT {$selectF} FROM {$this->tableName} WHERE