Framework files moved to lib/Roundcube

1 files changed, 0 insertions, 991 deletions

diff --git a/program/include/rcube_storage.php b/program/include/rcube_storage.php
deleted file mode 100644
index 1556aae41..000000000
--- a/program/include/rcube_storage.php
+++ /dev/null
@@ -1,991 +0,0 @@
-<?php
-
-/*
- +-----------------------------------------------------------------------+
- | program/include/rcube_storage.php                                     |
- |                                                                       |
- | This file is part of the Roundcube Webmail client                     |
- | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
- | Copyright (C) 2012, Kolab Systems AG                                  |
- |                                                                       |
- | Licensed under the GNU General Public License version 3 or            |
- | any later version with exceptions for skins & plugins.                |
- | See the README file for a full license statement.                     |
- |                                                                       |
- | PURPOSE:                                                              |
- |   Mail Storage Engine                                                 |
- |                                                                       |
- +-----------------------------------------------------------------------+
- | Author: Thomas Bruederli <roundcube@gmail.com>                        |
- | Author: Aleksander Machniak <alec@alec.pl>                            |
- +-----------------------------------------------------------------------+
-*/
-
-
-/**
- * Abstract class for accessing mail messages storage server
- *
- * @package    Framework
- * @subpackage Storage
- * @author     Thomas Bruederli <roundcube@gmail.com>
- * @author     Aleksander Machniak <alec@alec.pl>
- */
-abstract class rcube_storage
-{
-    /**
-     * Instance of connection object e.g. rcube_imap_generic
-     *
-     * @var mixed
-     */
-    public $conn;
-
-    protected $folder = 'INBOX';
-    protected $default_charset = 'ISO-8859-1';
-    protected $default_folders = array('INBOX');
-    protected $search_set;
-    protected $options = array('auth_method' => 'check');
-    protected $page_size = 10;
-    protected $threading = false;
-
-    /**
-     * All (additional) headers used (in any way) by Roundcube
-     * Not listed here: DATE, FROM, TO, CC, REPLY-TO, SUBJECT, CONTENT-TYPE, LIST-POST
-     * (used for messages listing) are hardcoded in rcube_imap_generic::fetchHeaders()
-     *
-     * @var array
-     */
-    protected $all_headers = array(
-        'IN-REPLY-TO',
-        'BCC',
-        'MESSAGE-ID',
-        'CONTENT-TRANSFER-ENCODING',
-        'REFERENCES',
-        'X-DRAFT-INFO',
-        'MAIL-FOLLOWUP-TO',
-        'MAIL-REPLY-TO',
-        'RETURN-PATH',
-    );
-
-    const UNKNOWN       = 0;
-    const NOPERM        = 1;
-    const READONLY      = 2;
-    const TRYCREATE     = 3;
-    const INUSE         = 4;
-    const OVERQUOTA     = 5;
-    const ALREADYEXISTS = 6;
-    const NONEXISTENT   = 7;
-    const CONTACTADMIN  = 8;
-
-
-    /**
-     * Connect to the server
-     *
-     * @param  string   $host    Host to connect
-     * @param  string   $user    Username for IMAP account
-     * @param  string   $pass    Password for IMAP account
-     * @param  integer  $port    Port to connect to
-     * @param  string   $use_ssl SSL schema (either ssl or tls) or null if plain connection
-     *
-     * @return boolean  TRUE on success, FALSE on failure
-     */
-    abstract function connect($host, $user, $pass, $port = 143, $use_ssl = null);
-
-
-    /**
-     * Close connection. Usually done on script shutdown
-     */
-    abstract function close();
-
-
-    /**
-     * Checks connection state.
-     *
-     * @return boolean  TRUE on success, FALSE on failure
-     */
-    abstract function is_connected();
-
-
-    /**
-     * Check connection state, connect if not connected.
-     *
-     * @return bool Connection state.
-     */
-    abstract function check_connection();
-
-
-    /**
-     * Returns code of last error
-     *
-     * @return int Error code
-     */
-    abstract function get_error_code();
-
-
-    /**
-     * Returns message of last error
-     *
-     * @return string Error message
-     */
-    abstract function get_error_str();
-
-
-    /**
-     * Returns code of last command response
-     *
-     * @return int Response code (class constant)
-     */
-    abstract function get_response_code();
-
-
-    /**
-     * Set connection and class options
-     *
-     * @param array $opt Options array
-     */
-    public function set_options($opt)
-    {
-        $this->options = array_merge($this->options, (array)$opt);
-    }
-
-
-    /**
-     * Activate/deactivate debug mode.
-     *
-     * @param boolean $dbg True if conversation with the server should be logged
-     */
-    abstract function set_debug($dbg = true);
-
-
-    /**
-     * Set default message charset.
-     *
-     * This will be used for message decoding if a charset specification is not available
-     *
-     * @param  string $cs Charset string
-     */
-    public function set_charset($cs)
-    {
-        $this->default_charset = $cs;
-    }
-
-
-    /**
-     * This list of folders will be listed above all other folders
-     *
-     * @param  array $arr Indexed list of folder names
-     */
-    public function set_default_folders($arr)
-    {
-        if (is_array($arr)) {
-            $this->default_folders = $arr;
-
-            // add inbox if not included
-            if (!in_array('INBOX', $this->default_folders)) {
-                array_unshift($this->default_folders, 'INBOX');
-            }
-        }
-    }
-
-
-    /**
-     * Set internal folder reference.
-     * All operations will be perfomed on this folder.
-     *
-     * @param  string $folder  Folder name
-     */
-    public function set_folder($folder)
-    {
-        if ($this->folder === $folder) {
-            return;
-        }
-
-        $this->folder = $folder;
-    }
-
-
-    /**
-     * Returns the currently used folder name
-     *
-     * @return string Name of the folder
-     */
-    public function get_folder()
-    {
-        return $this->folder;
-    }
-
-
-    /**
-     * Set internal list page number.
-     *
-     * @param int $page Page number to list
-     */
-    public function set_page($page)
-    {
-        $this->list_page = (int) $page;
-    }
-
-
-    /**
-     * Gets internal list page number.
-     *
-     * @return int Page number
-     */
-    public function get_page()
-    {
-        return $this->list_page;
-    }
-
-
-    /**
-     * Set internal page size
-     *
-     * @param int $size Number of messages to display on one page
-     */
-    public function set_pagesize($size)
-    {
-        $this->page_size = (int) $size;
-    }
-
-
-    /**
-     * Get internal page size
-     *
-     * @return int Number of messages to display on one page
-     */
-    public function get_pagesize()
-    {
-        return $this->page_size;
-    }
-
-
-    /**
-     * Save a search result for future message listing methods.
-     *
-     * @param  mixed  $set  Search set in driver specific format
-     */
-    abstract function set_search_set($set);
-
-
-    /**
-     * Return the saved search set.
-     *
-     * @return array Search set in driver specific format, NULL if search wasn't initialized
-     */
-    abstract function get_search_set();
-
-
-    /**
-     * Returns the storage server's (IMAP) capability
-     *
-     * @param   string  $cap Capability name
-     *
-     * @return  mixed   Capability value or TRUE if supported, FALSE if not
-     */
-    abstract function get_capability($cap);
-
-
-    /**
-     * Sets threading flag to the best supported THREAD algorithm.
-     * Enable/Disable threaded mode.
-     *
-     * @param  boolean  $enable TRUE to enable and FALSE
-     *
-     * @return mixed   Threading algorithm or False if THREAD is not supported
-     */
-    public function set_threading($enable = false)
-    {
-        $this->threading = false;
-
-        if ($enable && ($caps = $this->get_capability('THREAD'))) {
-            $methods = array('REFS', 'REFERENCES', 'ORDEREDSUBJECT');
-            $methods = array_intersect($methods, $caps);
-
-            $this->threading = array_shift($methods);
-        }
-
-        return $this->threading;
-    }
-
-
-    /**
-     * Get current threading flag.
-     *
-     * @return mixed  Threading algorithm or False if THREAD is not supported or disabled
-     */
-    public function get_threading()
-    {
-        return $this->threading;
-    }
-
-
-    /**
-     * Checks the PERMANENTFLAGS capability of the current folder
-     * and returns true if the given flag is supported by the server.
-     *
-     * @param   string  $flag Permanentflag name
-     *
-     * @return  boolean True if this flag is supported
-     */
-    abstract function check_permflag($flag);
-
-
-    /**
-     * Returns the delimiter that is used by the server
-     * for folder hierarchy separation.
-     *
-     * @return  string  Delimiter string
-     */
-    abstract function get_hierarchy_delimiter();
-
-
-    /**
-     * Get namespace
-     *
-     * @param string $name Namespace array index: personal, other, shared, prefix
-     *
-     * @return  array  Namespace data
-     */
-    abstract function get_namespace($name = null);
-
-
-    /**
-     * Get messages count for a specific folder.
-     *
-     * @param  string  $folder  Folder name
-     * @param  string  $mode    Mode for count [ALL|THREADS|UNSEEN|RECENT]
-     * @param  boolean $force   Force reading from server and update cache
-     * @param  boolean $status  Enables storing folder status info (max UID/count),
-     *                          required for folder_status()
-     *
-     * @return int     Number of messages
-     */
-    abstract function count($folder = null, $mode = 'ALL', $force = false, $status = true);
-
-
-    /**
-     * Public method for listing headers.
-     *
-     * @param   string   $folder     Folder name
-     * @param   int      $page       Current page to list
-     * @param   string   $sort_field Header field to sort by
-     * @param   string   $sort_order Sort order [ASC|DESC]
-     * @param   int      $slice      Number of slice items to extract from result array
-     *
-     * @return  array    Indexed array with message header objects
-     */
-    abstract function list_messages($folder = null, $page = null, $sort_field = null, $sort_order = null, $slice = 0);
-
-
-    /**
-     * Return sorted list of message UIDs
-     *
-     * @param string $folder     Folder to get index from
-     * @param string $sort_field Sort column
-     * @param string $sort_order Sort order [ASC, DESC]
-     *
-     * @return rcube_result_index|rcube_result_thread List of messages (UIDs)
-     */
-    abstract function index($folder = null, $sort_field = null, $sort_order = null);
-
-
-    /**
-     * Invoke search request to the server.
-     *
-     * @param  string  $folder     Folder name to search in
-     * @param  string  $str        Search criteria
-     * @param  string  $charset    Search charset
-     * @param  string  $sort_field Header field to sort by
-     *
-     * @todo: Search criteria should be provided in non-IMAP format, eg. array
-     */
-    abstract function search($folder = null, $str = 'ALL', $charset = null, $sort_field = null);
-
-
-    /**
-     * Direct (real and simple) search request (without result sorting and caching).
-     *
-     * @param  string  $folder  Folder name to search in
-     * @param  string  $str     Search string
-     *
-     * @return rcube_result_index  Search result (UIDs)
-     */
-    abstract function search_once($folder = null, $str = 'ALL');
-
-
-    /**
-     * Refresh saved search set
-     *
-     * @return array Current search set
-     */
-    abstract function refresh_search();
-
-
-    /* --------------------------------
-     *        messages management
-     * --------------------------------*/
-
-    /**
-     * Fetch message headers and body structure from the server and build
-     * an object structure similar to the one generated by PEAR::Mail_mimeDecode
-     *
-     * @param int     $uid     Message UID to fetch
-     * @param string  $folder  Folder to read from
-     *
-     * @return object rcube_message_header Message data
-     */
-    abstract function get_message($uid, $folder = null);
-
-
-    /**
-     * Return message headers object of a specific message
-     *
-     * @param int     $id       Message sequence ID or UID
-     * @param string  $folder   Folder to read from
-     * @param bool    $force    True to skip cache
-     *
-     * @return rcube_message_header Message headers
-     */
-    abstract function get_message_headers($uid, $folder = null, $force = false);
-
-
-    /**
-     * Fetch message body of a specific message from the server
-     *
-     * @param  int                $uid    Message UID
-     * @param  string             $part   Part number
-     * @param  rcube_message_part $o_part Part object created by get_structure()
-     * @param  mixed              $print  True to print part, ressource to write part contents in
-     * @param  resource           $fp     File pointer to save the message part
-     * @param  boolean            $skip_charset_conv Disables charset conversion
-     *
-     * @return string Message/part body if not printed
-     */
-    abstract function get_message_part($uid, $part = 1, $o_part = null, $print = null, $fp = null, $skip_charset_conv = false);
-
-
-    /**
-     * Fetch message body of a specific message from the server
-     *
-     * @param  int    $uid  Message UID
-     *
-     * @return string $part Message/part body
-     * @see    rcube_imap::get_message_part()
-     */
-    public function get_body($uid, $part = 1)
-    {
-        $headers = $this->get_message_headers($uid);
-        return rcube_charset::convert($this->get_message_part($uid, $part, null),
-            $headers->charset ? $headers->charset : $this->default_charset);
-    }
-
-
-    /**
-     * Returns the whole message source as string (or saves to a file)
-     *
-     * @param int      $uid Message UID
-     * @param resource $fp  File pointer to save the message
-     *
-     * @return string Message source string
-     */
-    abstract function get_raw_body($uid, $fp = null);
-
-
-    /**
-     * Returns the message headers as string
-     *
-     * @param int $uid  Message UID
-     *
-     * @return string Message headers string
-     */
-    abstract function get_raw_headers($uid);
-
-
-    /**
-     * Sends the whole message source to stdout
-     *
-     * @param int  $uid       Message UID
-     * @param bool $formatted Enables line-ending formatting
-     */
-    abstract function print_raw_body($uid, $formatted = true);
-
-
-    /**
-     * Set message flag to one or several messages
-     *
-     * @param mixed   $uids       Message UIDs as array or comma-separated string, or '*'
-     * @param string  $flag       Flag to set: SEEN, UNDELETED, DELETED, RECENT, ANSWERED, DRAFT, MDNSENT
-     * @param string  $folder     Folder name
-     * @param boolean $skip_cache True to skip message cache clean up
-     *
-     * @return bool  Operation status
-     */
-    abstract function set_flag($uids, $flag, $folder = null, $skip_cache = false);
-
-
-    /**
-     * Remove message flag for one or several messages
-     *
-     * @param mixed  $uids    Message UIDs as array or comma-separated string, or '*'
-     * @param string $flag    Flag to unset: SEEN, DELETED, RECENT, ANSWERED, DRAFT, MDNSENT
-     * @param string $folder  Folder name
-     *
-     * @return bool   Operation status
-     * @see set_flag
-     */
-    public function unset_flag($uids, $flag, $folder = null)
-    {
-        return $this->set_flag($uids, 'UN'.$flag, $folder);
-    }
-
-
-    /**
-     * Append a mail message (source) to a specific folder.
-     *
-     * @param string  $folder  Target folder
-     * @param string  $message The message source string or filename
-     * @param string  $headers Headers string if $message contains only the body
-     * @param boolean $is_file True if $message is a filename
-     * @param array   $flags   Message flags
-     * @param mixed   $date    Message internal date
-     *
-     * @return int|bool Appended message UID or True on success, False on error
-     */
-    abstract function save_message($folder, &$message, $headers = '', $is_file = false, $flags = array(), $date = null);
-
-
-    /**
-     * Move message(s) from one folder to another.
-     *
-     * @param mixed  $uids  Message UIDs as array or comma-separated string, or '*'
-     * @param string $to    Target folder
-     * @param string $from  Source folder
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function move_message($uids, $to, $from = null);
-
-
-    /**
-     * Copy message(s) from one mailbox to another.
-     *
-     * @param mixed  $uids  Message UIDs as array or comma-separated string, or '*'
-     * @param string $to    Target folder
-     * @param string $from  Source folder
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function copy_message($uids, $to, $from = null);
-
-
-    /**
-     * Mark message(s) as deleted and expunge.
-     *
-     * @param mixed  $uids    Message UIDs as array or comma-separated string, or '*'
-     * @param string $folder  Source folder
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function delete_message($uids, $folder = null);
-
-
-    /**
-     * Expunge message(s) and clear the cache.
-     *
-     * @param mixed   $uids        Message UIDs as array or comma-separated string, or '*'
-     * @param string  $folder      Folder name
-     * @param boolean $clear_cache False if cache should not be cleared
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function expunge_message($uids, $folder = null, $clear_cache = true);
-
-
-    /**
-     * Parse message UIDs input
-     *
-     * @param mixed  $uids  UIDs array or comma-separated list or '*' or '1:*'
-     *
-     * @return array Two elements array with UIDs converted to list and ALL flag
-     */
-    protected function parse_uids($uids)
-    {
-        if ($uids === '*' || $uids === '1:*') {
-            if (empty($this->search_set)) {
-                $uids = '1:*';
-                $all = true;
-            }
-            // get UIDs from current search set
-            else {
-                $uids = join(',', $this->search_set->get());
-            }
-        }
-        else {
-            if (is_array($uids)) {
-                $uids = join(',', $uids);
-            }
-
-            if (preg_match('/[^0-9,]/', $uids)) {
-                $uids = '';
-            }
-        }
-
-        return array($uids, (bool) $all);
-    }
-
-
-    /* --------------------------------
-     *        folder managment
-     * --------------------------------*/
-
-    /**
-     * Get a list of subscribed folders.
-     *
-     * @param   string  $root      Optional root folder
-     * @param   string  $name      Optional name pattern
-     * @param   string  $filter    Optional filter
-     * @param   string  $rights    Optional ACL requirements
-     * @param   bool    $skip_sort Enable to return unsorted list (for better performance)
-     *
-     * @return  array   List of folders
-     */
-    abstract function list_folders_subscribed($root = '', $name = '*', $filter = null, $rights = null, $skip_sort = false);
-
-
-    /**
-     * Get a list of all folders available on the server.
-     *
-     * @param string  $root      IMAP root dir
-     * @param string  $name      Optional name pattern
-     * @param mixed   $filter    Optional filter
-     * @param string  $rights    Optional ACL requirements
-     * @param bool    $skip_sort Enable to return unsorted list (for better performance)
-     *
-     * @return array Indexed array with folder names
-     */
-    abstract function list_folders($root = '', $name = '*', $filter = null, $rights = null, $skip_sort = false);
-
-
-    /**
-     * Subscribe to a specific folder(s)
-     *
-     * @param array $folders Folder name(s)
-     *
-     * @return boolean True on success
-     */
-    abstract function subscribe($folders);
-
-
-    /**
-     * Unsubscribe folder(s)
-     *
-     * @param array $folders Folder name(s)
-     *
-     * @return boolean True on success
-     */
-    abstract function unsubscribe($folders);
-
-
-    /**
-     * Create a new folder on the server.
-     *
-     * @param string  $folder    New folder name
-     * @param boolean $subscribe True if the newvfolder should be subscribed
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function create_folder($folder, $subscribe = false);
-
-
-    /**
-     * Set a new name to an existing folder
-     *
-     * @param string $folder   Folder to rename
-     * @param string $new_name New folder name
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function rename_folder($folder, $new_name);
-
-
-    /**
-     * Remove a folder from the server.
-     *
-     * @param string $folder Folder name
-     *
-     * @return boolean True on success, False on error
-     */
-    abstract function delete_folder($folder);
-
-
-    /**
-     * Send expunge command and clear the cache.
-     *
-     * @param string  $folder      Folder name
-     * @param boolean $clear_cache False if cache should not be cleared
-     *
-     * @return boolean True on success, False on error
-     */
-    public function expunge_folder($folder = null, $clear_cache = true)
-    {
-        return $this->expunge_message('*', $folder, $clear_cache);
-    }
-
-
-    /**
-     * Remove all messages in a folder..
-     *
-     * @param string  $folder  Folder name
-     *
-     * @return boolean True on success, False on error
-     */
-    public function clear_folder($folder = null)
-    {
-        return $this->delete_message('*', $folder);
-    }
-
-
-    /**
-     * Checks if folder exists and is subscribed
-     *
-     * @param string   $folder       Folder name
-     * @param boolean  $subscription Enable subscription checking
-     *
-     * @return boolean True if folder exists, False otherwise
-     */
-    abstract function folder_exists($folder, $subscription = false);
-
-
-    /**
-     * Get folder size (size of all messages in a folder)
-     *
-     * @param string $folder Folder name
-     *
-     * @return int Folder size in bytes, False on error
-     */
-    abstract function folder_size($folder);
-
-
-    /**
-     * Returns the namespace where the folder is in
-     *
-     * @param string $folder Folder name
-     *
-     * @return string One of 'personal', 'other' or 'shared'
-     */
-    abstract function folder_namespace($folder);
-
-
-    /**
-     * Gets folder attributes (from LIST response, e.g. \Noselect, \Noinferiors).
-     *
-     * @param string $folder  Folder name
-     * @param bool   $force   Set to True if attributes should be refreshed
-     *
-     * @return array Options list
-     */
-    abstract function folder_attributes($folder, $force = false);
-
-
-    /**
-     * Gets connection (and current folder) data: UIDVALIDITY, EXISTS, RECENT,
-     * PERMANENTFLAGS, UIDNEXT, UNSEEN
-     *
-     * @param string $folder Folder name
-     *
-     * @return array Data
-     */
-    abstract function folder_data($folder);
-
-
-    /**
-     * Returns extended information about the folder.
-     *
-     * @param string $folder Folder name
-     *
-     * @return array Data
-     */
-    abstract function folder_info($folder);
-
-
-    /**
-     * Returns current status of a folder
-     *
-     * @param string $folder Folder name
-     *
-     * @return int Folder status
-     */
-    abstract function folder_status($folder = null);
-
-
-    /**
-     * Synchronizes messages cache.
-     *
-     * @param string $folder Folder name
-     */
-    abstract function folder_sync($folder);
-
-
-    /**
-     * Modify folder name according to namespace.
-     * For output it removes prefix of the personal namespace if it's possible.
-     * For input it adds the prefix. Use it before creating a folder in root
-     * of the folders tree.
-     *
-     * @param string $folder  Folder name
-     * @param string $mode    Mode name (out/in)
-     *
-     * @return string Folder name
-     */
-    abstract function mod_folder($folder, $mode = 'out');
-
-
-    /**
-     * Create all folders specified as default
-     */
-    public function create_default_folders()
-    {
-        // create default folders if they do not exist
-        foreach ($this->default_folders as $folder) {
-            if (!$this->folder_exists($folder)) {
-                $this->create_folder($folder, true);
-            }
-            else if (!$this->folder_exists($folder, true)) {
-                $this->subscribe($folder);
-            }
-        }
-    }
-
-
-    /**
-     * Get mailbox quota information.
-     *
-     * @return mixed Quota info or False if not supported
-     */
-    abstract function get_quota();
-
-
-    /* -----------------------------------------
-     *   ACL and METADATA methods
-     * ----------------------------------------*/
-
-    /**
-     * Changes the ACL on the specified folder (SETACL)
-     *
-     * @param string $folder  Folder name
-     * @param string $user    User name
-     * @param string $acl     ACL string
-     *
-     * @return boolean True on success, False on failure
-     */
-    abstract function set_acl($folder, $user, $acl);
-
-
-    /**
-     * Removes any <identifier,rights> pair for the
-     * specified user from the ACL for the specified
-     * folder (DELETEACL).
-     *
-     * @param string $folder  Folder name
-     * @param string $user    User name
-     *
-     * @return boolean True on success, False on failure
-     */
-    abstract function delete_acl($folder, $user);
-
-
-    /**
-     * Returns the access control list for a folder (GETACL).
-     *
-     * @param string $folder Folder name
-     *
-     * @return array User-rights array on success, NULL on error
-     */
-    abstract function get_acl($folder);
-
-
-    /**
-     * Returns information about what rights can be granted to the
-     * user (identifier) in the ACL for the folder (LISTRIGHTS).
-     *
-     * @param string $folder  Folder name
-     * @param string $user    User name
-     *
-     * @return array List of user rights
-     */
-    abstract function list_rights($folder, $user);
-
-
-    /**
-     * Returns the set of rights that the current user has to a folder (MYRIGHTS).
-     *
-     * @param string $folder Folder name
-     *
-     * @return array MYRIGHTS response on success, NULL on error
-     */
-    abstract function my_rights($folder);
-
-
-    /**
-     * Sets metadata/annotations (SETMETADATA/SETANNOTATION)
-     *
-     * @param string $folder  Folder name (empty for server metadata)
-     * @param array  $entries Entry-value array (use NULL value as NIL)
-     *
-     * @return boolean True on success, False on failure
-     */
-    abstract function set_metadata($folder, $entries);
-
-
-    /**
-     * Unsets metadata/annotations (SETMETADATA/SETANNOTATION)
-     *
-     * @param string $folder  Folder name (empty for server metadata)
-     * @param array  $entries Entry names array
-     *
-     * @return boolean True on success, False on failure
-     */
-    abstract function delete_metadata($folder, $entries);
-
-
-    /**
-     * Returns folder metadata/annotations (GETMETADATA/GETANNOTATION).
-     *
-     * @param string $folder   Folder name (empty for server metadata)
-     * @param array  $entries  Entries
-     * @param array  $options  Command options (with MAXSIZE and DEPTH keys)
-     *
-     * @return array Metadata entry-value hash array on success, NULL on error
-     */
-    abstract function get_metadata($folder, $entries, $options = array());
-
-
-    /* -----------------------------------------
-     *   Cache related functions
-     * ----------------------------------------*/
-
-    /**
-     * Clears the cache.
-     *
-     * @param string  $key         Cache key name or pattern
-     * @param boolean $prefix_mode Enable it to clear all keys starting
-     *                             with prefix specified in $key
-     */
-    abstract function clear_cache($key = null, $prefix_mode = false);
-
-
-    /**
-     * Returns cached value
-     *
-     * @param string $key Cache key
-     *
-     * @return mixed Cached value
-     */
-    abstract function get_cache($key);
-
-
-    /**
-     * Delete outdated cache entries
-     */
-    abstract function expunge_cache();
-
-}  // end class rcube_storage