Horde_Imap_Client_Socket::_openMailbox PHP Method

    protected function _openMailbox(Horde_Imap_Client_Mailbox $mailbox, $mode)
    {
        $c = $this->_capability();
        $qresync = $c->isEnabled('QRESYNC');
        $cmd = $this->_command($mode == Horde_Imap_Client::OPEN_READONLY ? 'EXAMINE' : 'SELECT')->add($this->_getMboxFormatOb($mailbox));
        $pipeline = $this->_pipeline($cmd);
        /* If QRESYNC is available, synchronize the mailbox. */
        if ($qresync) {
            $this->_initCache();
            $md = $this->_cache->getMetaData($mailbox, null, array(self::CACHE_MODSEQ, 'uidvalid'));
            /* CACHE_MODSEQ can be set but 0 (NOMODSEQ was returned). */
            if (!empty($md[self::CACHE_MODSEQ])) {
                if ($uids = $this->_cache->get($mailbox)) {
                    $uids = $this->getIdsOb($uids);
                    /* Check for extra long UID string. Assume that any
                     * server that can handle QRESYNC can also handle long
                     * input strings (at least 8 KB), so 7 KB is as good as
                     * any guess as to an upper limit. If this occurs, provide
                     * a range string (min -> max) instead. */
                    if (strlen($uid_str = $uids->tostring_sort) > 7000) {
                        $uid_str = $uids->range_string;
                    }
                } else {
                    $uid_str = null;
                }
                /* Several things can happen with a QRESYNC:
                 * 1. UIDVALIDITY may have changed.  If so, we need to expire
                 * the cache immediately (done below).
                 * 2. NOMODSEQ may have been returned. We can keep current
                 * message cache data but won't be able to do flag caching.
                 * 3. VANISHED/FETCH information was returned. These responses
                 * will have already been handled by those response handlers.
                 * 4. We are already synced with the local server in which
                 * case it acts like a normal EXAMINE/SELECT. */
                $cmd->add(new Horde_Imap_Client_Data_Format_List(array('QRESYNC', new Horde_Imap_Client_Data_Format_List(array_filter(array($md['uidvalid'], $md[self::CACHE_MODSEQ], $uid_str))))));
            }
            /* Let the 'CLOSED' response code handle mailbox switching if
             * QRESYNC is active. */
            if ($this->_selected) {
                $pipeline->data['qresyncmbox'] = array($mailbox, $mode);
            } else {
                $this->_changeSelected($mailbox, $mode);
            }
        } else {
            if (!$c->isEnabled('CONDSTORE') && $this->_initCache() && $c->query('CONDSTORE')) {
                /* Activate CONDSTORE now if ENABLE is not available. */
                $cmd->add(new Horde_Imap_Client_Data_Format_List('CONDSTORE'));
                $c->enable('CONDSTORE');
            }
            $this->_changeSelected($mailbox, $mode);
        }
        try {
            $this->_sendCmd($pipeline);
        } catch (Horde_Imap_Client_Exception_ServerResponse $e) {
            // An EXAMINE/SELECT failure with a return of 'NO' will cause the
            // current mailbox to be unselected.
            if ($e->status === Horde_Imap_Client_Interaction_Server::NO) {
                $this->_changeSelected(null);
                $this->_mode = 0;
                if (!$e->getCode()) {
                    $e = new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Could not open mailbox \"%s\"."), Horde_Imap_Client_Exception::MAILBOX_NOOPEN);
                    $e->messagePrintf(array($mailbox));
                }
            }
            throw $e;
        }
        if ($qresync) {
            /* Mailbox is fully sync'd. */
            $this->_mailboxOb()->sync = true;
        }
    }