/**
  * update folder quota (check if server supports QUOTA first)
  * 
  * @param Felamimail_Model_Folder $_folder
  * @param Felamimail_Backend_ImapProxy $_imap
  */
 protected function _updateFolderQuota(Felamimail_Model_Folder $_folder, Felamimail_Backend_ImapProxy $_imap)
 {
     // only do it for INBOX
     if ($_folder->localname !== 'INBOX') {
         return;
     }
     $account = Felamimail_Controller_Account::getInstance()->get($_folder->account_id);
     if (!$account->hasCapability('QUOTA')) {
         if (Tinebase_Core::isLogLevel(Zend_Log::INFO)) {
             Tinebase_Core::getLogger()->debug(__METHOD__ . '::' . __LINE__ . ' Account ' . $account->name . ' has no QUOTA capability');
         }
         return;
     }
     if (Tinebase_Core::isLogLevel(Zend_Log::DEBUG)) {
         Tinebase_Core::getLogger()->debug(__METHOD__ . '::' . __LINE__ . ' Getting quota for INBOX ' . $_folder->getId());
     }
     // get quota and save in folder
     $quota = $_imap->getQuota($_folder->localname);
     if (!empty($quota) && isset($quota['STORAGE'])) {
         $_folder->quota_usage = $quota['STORAGE']['usage'];
         $_folder->quota_limit = $quota['STORAGE']['limit'];
     } else {
         $_folder->quota_usage = 0;
         $_folder->quota_limit = 0;
     }
     if (Tinebase_Core::isLogLevel(Zend_Log::TRACE)) {
         Tinebase_Core::getLogger()->trace(__METHOD__ . '::' . __LINE__ . ' ' . print_r($quota, TRUE));
     }
 }