How to browse history in php, browse history in php_PHP tutorial

/**
 * 商品历史浏览记录
 * $data 商品记录信息
 */
private function _history($data)
{
  if(!$data || !is_array($data))
  {
    return false;
  }
  //判断cookie类里面是否有浏览记录
  if($this->_request->getCookie('history'))
  {
    $history = unserialize($this->_request->getCookie('history'));
    array_unshift($history, $data); //在浏览记录顶部加入
    /* 去除重复记录 */
    $rows = array();
    foreach ($history as $v)
    {
      if(in_array($v, $rows))
      {
        continue;
      }
      $rows[] = $v;
    }
    /* 如果记录数量多余5则去除 */
    while (count($rows) > 5)
    {
      array_pop($rows); //弹出
    }
    setcookie('history',serialize($rows),time()+3600*24*30,'/');
  }
  else
  {
    $history = serialize(array($data));
    setcookie('history',$history,time()+3600*24*30,'/');
  }
}