/**
  * 获取开启了品牌logo广告位的公司列表
  * @param $cityid
  */
 public function getLogoCompanyList($cityid)
 {
     $key = Util_MemCacheKey::getLogoCompanyList($cityid);
     APF::get_instance()->benchmark_begin(__CLASS__ . " getLogoCompanyList ");
     $memcache = APF_Cache_Factory::get_instance()->get_memcache();
     $value = $memcache->get($key);
     if (!$value && $value !== array()) {
         $time = Util_MemCacheTime::getLogoCompanyList();
         $value = parent::getLogoCompanyList($cityid);
         $memcache->add($key, $value, 0, $time);
     }
     APF::get_instance()->benchmark_end(__CLASS__ . " getLogoCompanyList ");
     return $value;
 }