ai có thể giải thích cơ chế hoạt động của backup này ko

function addZip($FileList, $domain_id, $uid){
$i=0;
$zip=new ZipArchive();
$newArchive='backup_'.$domain_id.'_'.time().'.zip';
@mysql_query("INSERT INTO `backup` SET `uid`='{$uid}', `name`='{$newArchive}', `time`='".time()."', `domain_id`='{$domain_id}'");
if($zip->open(dirname(__FILE__).'/../backup_archive/'.$newArchive, ZipArchive::CREATE)==TRUE){
foreach($FileList as $rows){
$i++;
if($rows['name']!=''){
$zip->addFile(dirname(__FILE__)."/../serverFolder/space_data/[id_{$rows['id']}][fid_{$rows['move']}][name_{$rows['name']}][domain_id_{$rows['domain_id']}].txt", $rows['zipdir']);
echo '['.$i.'] : '.$rows['zipdir'].' ('.value_size(file_get_contents(dirname(__FILE__)."/../serverFolder/space_data/[id_{$rows['id']}][fid_{$rows['move']}][name_{$rows['name']}][domain_id_{$rows['domain_id']}].txt")).' Kb)<br>';
}
}
}
}
function list_rep($FileList){
$list='';
foreach($FileList as $rows){
if($rows['name']!=''){
$list.='{"id":"'.$rows['id'].'","move":"'.$rows['move'].'","name":"'.$rows['name'].'","zipdir":"'.$rows['zipdir'].'","type":"'.$rows['type'].'","domain_id":"'.$rows['domain_id'].'"},';
}else{
$list.=list_rep($rows);
}
}
return $list;
}
function get($domain_id, $folder, $dir){
$get=@mysql_query("SELECT * FROM `manager` WHERE `fid`='{$folder}' and `domain_id`='{$domain_id}'");
$list=array();
if($folder!=0){
$myDir=@mysql_fetch_array(@mysql_query("SELECT * FROM `manager` WHERE `id`='{$folder}' and `domain_id`='{$domain_id}'"));
$dir.=$myDir['name'].'/';
}
if(@mysql_num_rows($get)>0){
while($rows=@mysql_fetch_array($get)){
if($rows['type']!='folder'){
$list[]=array(
'id'=>$rows['id'],
'move'=>$rows['fid'],
'name'=>$rows['name'],
'zipdir'=>$dir.$rows['name'],
'type'=>$rows['type'],
'domain_id'=>$rows['domain_id']
);
}else{
$list[]=get($domain_id, $rows['id'], $dir);
}
}
}else{
$select=@mysql_fetch_array(@mysql_query("SELECT * FROM `manager` WHERE `id`='{$folder}' and `domain_id`='{$domain_id}'"));
}
return $list;
}
function ZipBackup($domain_id, $uid){
return addZip(json_decode('['.list_rep(get($domain_id,0,'')).'{}]', true), $domain_id, $uid);
}