Merge branch 'pdo'

Conflicts:
	CHANGELOG

13 files changed, 1786 insertions, 952 deletions

diff --git a/program/include/rcube.php b/program/include/rcube.php
index ab5879dc5..494b5c3dd 100644
--- a/program/include/rcube.php
+++ b/program/include/rcube.php
@@ -49,14 +49,14 @@ class rcube
   /**
    * Instace of database class.
    *
-   * @var rcube_mdb2
+   * @var rcube_pdo
    */
   public $db;
 
   /**
    * Instace of Memcache class.
    *
-   * @var rcube_mdb2
+   * @var Memcache
    */
   public $memcache;
 
@@ -160,15 +160,13 @@ class rcube
   /**
    * Get the current database connection
    *
-   * @return rcube_mdb2  Database connection object
+   * @return rcube_pdo  Database connection object
    */
   public function get_dbh()
   {
     if (!$this->db) {
       $config_all = $this->config->all();
-
-      $this->db = new rcube_mdb2($config_all['db_dsnw'], $config_all['db_dsnr'], $config_all['db_persistent']);
-      $this->db->sqlite_initials = INSTALL_PATH . 'SQL/sqlite.initial.sql';
+      $this->db = rcube_db::factory($config_all['db_dsnw'], $config_all['db_dsnr'], $config_all['db_persistent']);
       $this->db->set_debug((bool)$config_all['sql_debug']);
     }
 
diff --git a/program/include/rcube_cache.php b/program/include/rcube_cache.php
index 807d20c0e..17a8859d8 100644
--- a/program/include/rcube_cache.php
+++ b/program/include/rcube_cache.php
@@ -33,9 +33,9 @@
 class rcube_cache
 {
     /**
-     * Instance of rcube_mdb2 or Memcache class
+     * Instance of database handler
      *
-     * @var rcube_mdb2/Memcache
+     * @var rcube_db|Memcache|bool
      */
     private $db;
     private $type;
diff --git a/program/include/rcube_contacts.php b/program/include/rcube_contacts.php
index f7fc65147..534a65cb9 100644
--- a/program/include/rcube_contacts.php
+++ b/program/include/rcube_contacts.php
@@ -36,7 +36,7 @@ class rcube_contacts extends rcube_addressbook
     /**
      * Store database connection.
      *
-     * @var rcube_mdb2
+     * @var rcube_db
      */
     private $db = null;
     private $user_id = 0;
@@ -934,8 +934,8 @@ class rcube_contacts extends rcube_addressbook
                 $contact_id
             );
 
-            if ($this->db->db_error)
-                $this->set_error(self::ERROR_SAVING, $this->db->db_error_msg);
+            if ($error = $this->db->is_error())
+                $this->set_error(self::ERROR_SAVING, $error);
             else
                 $added++;
         }
@@ -990,9 +990,10 @@ class rcube_contacts extends rcube_addressbook
                 $checkname);
 
             // append number to make name unique
-            if ($hit = $this->db->num_rows($sql_result))
+            if ($hit = $this->db->fetch_array($sql_result)) {
                 $checkname = $name . ' ' . $num++;
-        } while ($hit > 0);
+            }
+        } while ($hit);
 
         return $checkname;
     }
diff --git a/program/include/rcube_db.php b/program/include/rcube_db.php
new file mode 100644
index 000000000..d0d213cd0
--- /dev/null
+++ b/program/include/rcube_db.php
@@ -0,0 +1,992 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_db.php                                          |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
+ |                                                                       |
+ | 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:                                                              |
+ |   Database wrapper class that implements PHP PDO functions            |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+
+/**
+ * Database independent query interface
+ *
+ * This is a wrapper for the PHP PDO
+ *
+ * @package Database
+ * @version 1.0
+ */
+class rcube_db
+{
+    protected $db_dsnw;               // DSN for write operations
+    protected $db_dsnr;               // DSN for read operations
+    protected $db_connected = false;  // Already connected ?
+    protected $db_mode;               // Connection mode
+    protected $dbh;                   // Connection handle
+
+    protected $db_error        = false;
+    protected $db_error_msg    = '';
+    protected $conn_failure    = false;
+    protected $a_query_results = array('dummy');
+    protected $last_res_id     = 0;
+    protected $db_index        = 0;
+    protected $tables;
+    protected $variables;
+
+    protected $options = array(
+        // column/table quotes
+        'identifier_start' => '"',
+        'identifier_end'   => '"',
+    );
+
+
+    /**
+     * Factory, returns driver-specific instance of the class
+     *
+     * @param string $db_dsnw DSN for read/write operations
+     * @param string $db_dsnr Optional DSN for read only operations
+     * @param bool   $pconn   Enables persistent connections
+     *
+     * @return rcube_db Object instance
+     */
+    public static function factory($db_dsnw, $db_dsnr = '', $pconn = false)
+    {
+        $driver     = strtolower(substr($db_dsnw, 0, strpos($db_dsnw, ':')));
+        $driver_map = array(
+            'sqlite2' => 'sqlite',
+            'sybase'  => 'mssql',
+            'dblib'   => 'mssql',
+            'mysqli'  => 'mysql',
+        );
+
+        $driver = isset($driver_map[$driver]) ? $driver_map[$driver] : $driver;
+        $class  = "rcube_db_$driver";
+
+        if (!class_exists($class)) {
+            rcube::raise_error(array('code' => 600, 'type' => 'db',
+                'line' => __LINE__, 'file' => __FILE__,
+                'message' => "Configuration error. Unsupported database driver: $driver"),
+                true, true);
+        }
+
+        return new $class($db_dsnw, $db_dsnr, $pconn);
+    }
+
+    /**
+     * Object constructor
+     *
+     * @param string $db_dsnw DSN for read/write operations
+     * @param string $db_dsnr Optional DSN for read only operations
+     * @param bool   $pconn   Enables persistent connections
+     */
+    public function __construct($db_dsnw, $db_dsnr = '', $pconn = false)
+    {
+        if (empty($db_dsnr)) {
+            $db_dsnr = $db_dsnw;
+        }
+
+        $this->db_dsnw  = $db_dsnw;
+        $this->db_dsnr  = $db_dsnr;
+        $this->db_pconn = $pconn;
+
+        $this->db_dsnw_array = self::parse_dsn($db_dsnw);
+        $this->db_dsnr_array = self::parse_dsn($db_dsnr);
+
+        // Initialize driver class
+        $this->init();
+    }
+
+    /**
+     * Initialization of the object with driver specific code
+     */
+    protected function init()
+    {
+        // To be used by driver classes
+    }
+
+    /**
+     * Connect to specific database
+     *
+     * @param array $dsn DSN for DB connections
+     *
+     * @return PDO database handle
+     */
+    protected function dsn_connect($dsn)
+    {
+        $this->db_error     = false;
+        $this->db_error_msg = null;
+
+        // Get database specific connection options
+        $dsn_string  = $this->dsn_string($dsn);
+        $dsn_options = $this->dsn_options($dsn);
+
+        if ($db_pconn) {
+            $dsn_options[PDO::ATTR_PERSISTENT] = true;
+        }
+
+        // Connect
+        try {
+            // with this check we skip fatal error on PDO object creation
+            if (!class_exists('PDO', false)) {
+                throw new Exception('PDO extension not loaded. See http://php.net/manual/en/intro.pdo.php');
+            }
+
+            $this->conn_prepare($dsn);
+
+            $dbh = new PDO($dsn_string, $dsn['username'], $dsn['password'], $dsn_options);
+
+            // don't throw exceptions or warnings
+            $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
+        }
+        catch (Exception $e) {
+            $this->db_error     = true;
+            $this->db_error_msg = $e->getMessage();
+
+            rcube::raise_error(array('code' => 500, 'type' => 'db',
+                'line' => __LINE__, 'file' => __FILE__,
+                'message' => $this->db_error_msg), true, false);
+
+            return null;
+        }
+
+        $this->conn_configure($dsn, $dbh);
+
+        return $dbh;
+    }
+
+    /**
+     * Driver-specific preparation of database connection
+     *
+     * @param array $dsn DSN for DB connections
+     */
+    protected function conn_prepare($dsn)
+    {
+    }
+
+    /**
+     * Driver-specific configuration of database connection
+     *
+     * @param array $dsn DSN for DB connections
+     * @param PDO   $dbh Connection handler
+     */
+    protected function conn_configure($dsn, $dbh)
+    {
+    }
+
+    /**
+     * Driver-specific database character set setting
+     *
+     * @param string $charset Character set name
+     */
+    protected function set_charset($charset)
+    {
+        $this->query("SET NAMES 'utf8'");
+    }
+
+    /**
+     * Connect to appropiate database depending on the operation
+     *
+     * @param string $mode Connection mode (r|w)
+     */
+    public function db_connect($mode)
+    {
+        // previous connection failed, don't attempt to connect again
+        if ($this->conn_failure) {
+            return;
+        }
+
+        // no replication
+        if ($this->db_dsnw == $this->db_dsnr) {
+            $mode = 'w';
+        }
+
+        // Already connected
+        if ($this->db_connected) {
+            // connected to db with the same or "higher" mode
+            if ($this->db_mode == 'w' || $this->db_mode == $mode) {
+                return;
+            }
+        }
+
+        $dsn = ($mode == 'r') ? $this->db_dsnr_array : $this->db_dsnw_array;
+
+        $this->dbh          = $this->dsn_connect($dsn);
+        $this->db_connected = is_object($this->dbh);
+
+        // use write-master when read-only fails
+        if (!$this->db_connected && $mode == 'r') {
+            $mode = 'w';
+            $this->dbh          = $this->dsn_connect($this->db_dsnw_array);
+            $this->db_connected = is_object($this->dbh);
+        }
+
+        if ($this->db_connected) {
+            $this->db_mode = $mode;
+            $this->set_charset('utf8');
+        }
+        else {
+            $this->conn_failure = true;
+        }
+    }
+
+    /**
+     * Activate/deactivate debug mode
+     *
+     * @param boolean $dbg True if SQL queries should be logged
+     */
+    public function set_debug($dbg = true)
+    {
+        $this->options['debug_mode'] = $dbg;
+    }
+
+    /**
+     * Writes debug information/query to 'sql' log file
+     *
+     * @param string $query SQL query
+     */
+    protected function debug($query)
+    {
+        if ($this->options['debug_mode']) {
+            rcube::write_log('sql', '[' . (++$this->db_index) . '] ' . $query . ';');
+        }
+    }
+
+    /**
+     * Getter for error state
+     *
+     * @return boolean True on error
+     */
+    public function is_error()
+    {
+        return $this->db_error ? $this->db_error_msg : false;
+    }
+
+    /**
+     * Connection state checker
+     *
+     * @return boolean True if in connected state
+     */
+    public function is_connected()
+    {
+        return !is_object($this->dbh) ? false : $this->db_connected;
+    }
+
+    /**
+     * Is database replication configured?
+     *
+     * @return bool Returns true if dsnw != dsnr
+     */
+    public function is_replicated()
+    {
+      return !empty($this->db_dsnr) && $this->db_dsnw != $this->db_dsnr;
+    }
+
+    /**
+     * Get database runtime variables
+     *
+     * @param string $varname Variable name
+     * @param mixed  $default Default value if variable is not set
+     *
+     * @return mixed Variable value or default
+     */
+    public function get_variable($varname, $default = null)
+    {
+        // to be implemented by driver class
+        return $default;
+    }
+
+    /**
+     * Execute a SQL query
+     *
+     * @param string SQL query to execute
+     * @param mixed  Values to be inserted in query
+     *
+     * @return number  Query handle identifier
+     */
+    public function query()
+    {
+        $params = func_get_args();
+        $query = array_shift($params);
+
+        // Support one argument of type array, instead of n arguments
+        if (count($params) == 1 && is_array($params[0])) {
+            $params = $params[0];
+        }
+
+        return $this->_query($query, 0, 0, $params);
+    }
+
+    /**
+     * Execute a SQL query with limits
+     *
+     * @param string SQL query to execute
+     * @param int    Offset for LIMIT statement
+     * @param int    Number of rows for LIMIT statement
+     * @param mixed  Values to be inserted in query
+     *
+     * @return int Query handle identifier
+     */
+    public function limitquery()
+    {
+        $params  = func_get_args();
+        $query   = array_shift($params);
+        $offset  = array_shift($params);
+        $numrows = array_shift($params);
+
+        return $this->_query($query, $offset, $numrows, $params);
+    }
+
+    /**
+     * Execute a SQL query with limits
+     *
+     * @param string $query   SQL query to execute
+     * @param int    $offset  Offset for LIMIT statement
+     * @param int    $numrows Number of rows for LIMIT statement
+     * @param array  $params  Values to be inserted in query
+     *
+     * @return int Query handle identifier
+     */
+    protected function _query($query, $offset, $numrows, $params)
+    {
+        // Read or write ?
+        $mode = preg_match('/^(select|show)/i', ltrim($query)) ? 'r' : 'w';
+
+        $this->db_connect($mode);
+
+        // check connection before proceeding
+        if (!$this->is_connected()) {
+            return null;
+        }
+
+        if ($numrows || $offset) {
+            $query = $this->set_limit($query, $numrows, $offset);
+        }
+
+        $params = (array) $params;
+
+        // Because in Roundcube we mostly use queries that are
+        // executed only once, we will not use prepared queries
+        $pos = 0;
+        $idx = 0;
+
+        while ($pos = strpos($query, '?', $pos)) {
+            $val = $this->quote($params[$idx++]);
+            unset($params[$idx-1]);
+            $query = substr_replace($query, $val, $pos, 1);
+            $pos += strlen($val);
+        }
+
+        $query = rtrim($query, ';');
+
+        $this->debug($query);
+
+        $query = $this->dbh->query($query);
+
+        if ($query === false) {
+            $error = $this->dbh->errorInfo();
+            $this->db_error = true;
+            $this->db_error_msg = sprintf('[%s] %s', $error[1], $error[2]);
+
+            rcube::raise_error(array('code' => 500, 'type' => 'db',
+                'line' => __LINE__, 'file' => __FILE__,
+                'message' => $this->db_error_msg), true, false);
+        }
+
+        // add result, even if it's an error
+        return $this->_add_result($query);
+    }
+
+    /**
+     * Get number of affected rows for the last query
+     *
+     * @param  number $res_id Optional query handle identifier
+     *
+     * @return int Number of rows or false on failure
+     */
+    public function affected_rows($res_id = null)
+    {
+        if ($result = $this->_get_result($res_id)) {
+            return $result->rowCount();
+        }
+
+        return 0;
+    }
+
+    /**
+     * Get last inserted record ID
+     *
+     * @param string $table Table name (to find the incremented sequence)
+     *
+     * @return mixed ID or false on failure
+     */
+    public function insert_id($table = '')
+    {
+        if (!$this->db_connected || $this->db_mode == 'r') {
+            return false;
+        }
+
+        if ($table) {
+            // resolve table name
+            $table = $this->table_name($table);
+        }
+
+        $id = $this->dbh->lastInsertId($table);
+
+        return $id;
+    }
+
+    /**
+     * Get an associative array for one row
+     * If no query handle is specified, the last query will be taken as reference
+     *
+     * @param int $res_id Optional query handle identifier
+     *
+     * @return mixed Array with col values or false on failure
+     */
+    public function fetch_assoc($res_id = null)
+    {
+        $result = $this->_get_result($res_id);
+        return $this->_fetch_row($result, PDO::FETCH_ASSOC);
+    }
+
+    /**
+     * Get an index array for one row
+     * If no query handle is specified, the last query will be taken as reference
+     *
+     * @param int $res_id Optional query handle identifier
+     *
+     * @return mixed Array with col values or false on failure
+     */
+    public function fetch_array($res_id = null)
+    {
+        $result = $this->_get_result($res_id);
+        return $this->_fetch_row($result, PDO::FETCH_NUM);
+    }
+
+    /**
+     * Get col values for a result row
+     *
+     * @param PDOStatement $result Result handle
+     * @param int          $mode   Fetch mode identifier
+     *
+     * @return mixed Array with col values or false on failure
+     */
+    protected function _fetch_row($result, $mode)
+    {
+        if (!is_object($result) || !$this->is_connected()) {
+            return false;
+        }
+
+        return $result->fetch($mode);
+    }
+
+    /**
+     * Adds LIMIT,OFFSET clauses to the query
+     *
+     * @param string $query  SQL query
+     * @param int    $limit  Number of rows
+     * @param int    $offset Offset
+     *
+     * @return string SQL query
+     */
+    protected function set_limit($query, $limit = 0, $offset = 0)
+    {
+        if ($limit) {
+            $query .= ' LIMIT ' . intval($limit);
+        }
+
+        if ($offset) {
+            $query .= ' OFFSET ' . intval($offset);
+        }
+
+        return $query;
+    }
+
+    /**
+     * Returns list of tables in a database
+     *
+     * @return array List of all tables of the current database
+     */
+    public function list_tables()
+    {
+        // get tables if not cached
+        if ($this->tables === null) {
+            $q = $this->query('SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES ORDER BY TABLE_NAME');
+
+            if ($res = $this->_get_result($q)) {
+                $this->tables = $res->fetchAll(PDO::FETCH_COLUMN, 0);
+            }
+            else {
+                $this->tables = array();
+            }
+        }
+
+        return $this->tables;
+    }
+
+    /**
+     * Returns list of columns in database table
+     *
+     * @param string $table Table name
+     *
+     * @return array List of table cols
+     */
+    public function list_cols($table)
+    {
+        $q = $this->query('SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = ?',
+            array($table));
+
+        if ($res = $this->_get_result($q)) {
+            return $res->fetchAll(PDO::FETCH_COLUMN, 0);
+        }
+
+        return array();
+    }
+
+    /**
+     * Formats input so it can be safely used in a query
+     *
+     * @param mixed  $input Value to quote
+     * @param string $type  Type of data
+     *
+     * @return string Quoted/converted string for use in query
+     */
+    public function quote($input, $type = null)
+    {
+        // handle int directly for better performance
+        if ($type == 'integer' || $type == 'int') {
+            return intval($input);
+        }
+
+        // create DB handle if not available
+        if (!$this->dbh) {
+            $this->db_connect('r');
+        }
+
+        if ($this->dbh) {
+            $map = array(
+                'bool'    => PDO::PARAM_BOOL,
+                'integer' => PDO::PARAM_INT,
+            );
+            $type = isset($map[$type]) ? $map[$type] : PDO::PARAM_STR;
+            return $this->dbh->quote($input, $type);
+        }
+
+        return 'NULL';
+    }
+
+    /**
+     * Quotes a string so it can be safely used as a table or column name
+     *
+     * @param string $str Value to quote
+     *
+     * @return string Quoted string for use in query
+     * @deprecated    Replaced by rcube_db::quote_identifier
+     * @see           rcube_db::quote_identifier
+     */
+    public function quoteIdentifier($str)
+    {
+        return $this->quote_identifier($str);
+    }
+
+    /**
+     * Quotes a string so it can be safely used as a table or column name
+     *
+     * @param string $str Value to quote
+     *
+     * @return string Quoted string for use in query
+     */
+    public function quote_identifier($str)
+    {
+        $start = $this->options['identifier_start'];
+        $end   = $this->options['identifier_end'];
+        $name  = array();
+
+        foreach (explode('.', $str) as $elem) {
+            $elem = str_replace(array($start, $end), '', $elem);
+            $name[] = $start . $elem . $end;
+        }
+
+        return  implode($name, '.');
+    }
+
+    /**
+     * Return SQL function for current time and date
+     *
+     * @return string SQL function to use in query
+     */
+    public function now()
+    {
+        return "now()";
+    }
+
+    /**
+     * Return list of elements for use with SQL's IN clause
+     *
+     * @param array  $arr  Input array
+     * @param string $type Type of data
+     *
+     * @return string Comma-separated list of quoted values for use in query
+     */
+    public function array2list($arr, $type = null)
+    {
+        if (!is_array($arr)) {
+            return $this->quote($arr, $type);
+        }
+
+        foreach ($arr as $idx => $item) {
+            $arr[$idx] = $this->quote($item, $type);
+        }
+
+        return implode(',', $arr);
+    }
+
+    /**
+     * Return SQL statement to convert a field value into a unix timestamp
+     *
+     * This method is deprecated and should not be used anymore due to limitations
+     * of timestamp functions in Mysql (year 2038 problem)
+     *
+     * @param string $field Field name
+     *
+     * @return string  SQL statement to use in query
+     * @deprecated
+     */
+    public function unixtimestamp($field)
+    {
+        return "UNIX_TIMESTAMP($field)";
+    }
+
+    /**
+     * Return SQL statement to convert from a unix timestamp
+     *
+     * @param int $timestamp Unix timestamp
+     *
+     * @return string Date string in db-specific format
+     */
+    public function fromunixtime($timestamp)
+    {
+        return date("'Y-m-d H:i:s'", $timestamp);
+    }
+
+    /**
+     * Return SQL statement for case insensitive LIKE
+     *
+     * @param string $column Field name
+     * @param string $value  Search value
+     *
+     * @return string SQL statement to use in query
+     */
+    public function ilike($column, $value)
+    {
+        return $this->quote_identifier($column).' LIKE '.$this->quote($value);
+    }
+
+    /**
+     * Abstract SQL statement for value concatenation
+     *
+     * @return string SQL statement to be used in query
+     */
+    public function concat(/* col1, col2, ... */)
+    {
+        $args = func_get_args();
+        if (is_array($args[0])) {
+            $args = $args[0];
+        }
+
+        return '(' . join(' || ', $args) . ')';
+    }
+
+    /**
+     * Encodes non-UTF-8 characters in string/array/object (recursive)
+     *
+     * @param mixed $input Data to fix
+     *
+     * @return mixed Properly UTF-8 encoded data
+     */
+    public static function encode($input)
+    {
+        if (is_object($input)) {
+            foreach (get_object_vars($input) as $idx => $value) {
+                $input->$idx = self::encode($value);
+            }
+            return $input;
+        }
+        else if (is_array($input)) {
+            foreach ($input as $idx => $value) {
+                $input[$idx] = self::encode($value);
+            }
+            return $input;
+        }
+
+        return utf8_encode($input);
+    }
+
+    /**
+     * Decodes encoded UTF-8 string/object/array (recursive)
+     *
+     * @param mixed $input Input data
+     *
+     * @return mixed Decoded data
+     */
+    public static function decode($input)
+    {
+        if (is_object($input)) {
+            foreach (get_object_vars($input) as $idx => $value) {
+                $input->$idx = self::decode($value);
+            }
+            return $input;
+        }
+        else if (is_array($input)) {
+            foreach ($input as $idx => $value) {
+                $input[$idx] = self::decode($value);
+            }
+            return $input;
+        }
+
+        return utf8_decode($input);
+    }
+
+    /**
+     * Adds a query result and returns a handle ID
+     *
+     * @param object $res Query handle
+     *
+     * @return int Handle ID
+     */
+    protected function _add_result($res)
+    {
+        $this->last_res_id = sizeof($this->a_query_results);
+        $this->a_query_results[$this->last_res_id] = $res;
+
+        return $this->last_res_id;
+    }
+
+    /**
+     * Resolves a given handle ID and returns the according query handle
+     * If no ID is specified, the last resource handle will be returned
+     *
+     * @param int $res_id Handle ID
+     *
+     * @return mixed Resource handle or false on failure
+     */
+    protected function _get_result($res_id = null)
+    {
+        if ($res_id == null) {
+            $res_id = $this->last_res_id;
+        }
+
+        if (!empty($this->a_query_results[$res_id])) {
+            return $this->a_query_results[$res_id];
+        }
+
+        return false;
+    }
+
+    /**
+     * Return correct name for a specific database table
+     *
+     * @param string $table Table name
+     *
+     * @return string Translated table name
+     */
+    public function table_name($table)
+    {
+        $rcube = rcube::get_instance();
+
+        // return table name if configured
+        $config_key = 'db_table_'.$table;
+
+        if ($name = $rcube->config->get($config_key)) {
+            return $name;
+        }
+
+        return $table;
+    }
+
+    /**
+     * MDB2 DSN string parser
+     *
+     * @param string $sequence Secuence name
+     *
+     * @return array DSN parameters
+     */
+    public static function parse_dsn($dsn)
+    {
+        if (empty($dsn)) {
+            return null;
+        }
+
+        // Find phptype and dbsyntax
+        if (($pos = strpos($dsn, '://')) !== false) {
+            $str = substr($dsn, 0, $pos);
+            $dsn = substr($dsn, $pos + 3);
+        }
+        else {
+            $str = $dsn;
+            $dsn = null;
+        }
+
+        // Get phptype and dbsyntax
+        // $str => phptype(dbsyntax)
+        if (preg_match('|^(.+?)\((.*?)\)$|', $str, $arr)) {
+            $parsed['phptype']  = $arr[1];
+            $parsed['dbsyntax'] = !$arr[2] ? $arr[1] : $arr[2];
+        }
+        else {
+            $parsed['phptype']  = $str;
+            $parsed['dbsyntax'] = $str;
+        }
+
+        if (empty($dsn)) {
+            return $parsed;
+        }
+
+        // Get (if found): username and password
+        // $dsn => username:password@protocol+hostspec/database
+        if (($at = strrpos($dsn,'@')) !== false) {
+            $str = substr($dsn, 0, $at);
+            $dsn = substr($dsn, $at + 1);
+            if (($pos = strpos($str, ':')) !== false) {
+                $parsed['username'] = rawurldecode(substr($str, 0, $pos));
+                $parsed['password'] = rawurldecode(substr($str, $pos + 1));
+            }
+            else {
+                $parsed['username'] = rawurldecode($str);
+            }
+        }
+
+        // Find protocol and hostspec
+
+        // $dsn => proto(proto_opts)/database
+        if (preg_match('|^([^(]+)\((.*?)\)/?(.*?)$|', $dsn, $match)) {
+            $proto       = $match[1];
+            $proto_opts  = $match[2] ? $match[2] : false;
+            $dsn         = $match[3];
+        }
+        // $dsn => protocol+hostspec/database (old format)
+        else {
+            if (strpos($dsn, '+') !== false) {
+                list($proto, $dsn) = explode('+', $dsn, 2);
+            }
+            if (   strpos($dsn, '//') === 0
+                && strpos($dsn, '/', 2) !== false
+                && $parsed['phptype'] == 'oci8'
+            ) {
+                //oracle's "Easy Connect" syntax:
+                //"username/password@[//]host[:port][/service_name]"
+                //e.g. "scott/tiger@//mymachine:1521/oracle"
+                $proto_opts = $dsn;
+                $pos = strrpos($proto_opts, '/');
+                $dsn = substr($proto_opts, $pos + 1);
+                $proto_opts = substr($proto_opts, 0, $pos);
+            }
+            else if (strpos($dsn, '/') !== false) {
+                list($proto_opts, $dsn) = explode('/', $dsn, 2);
+            }
+            else {
+                $proto_opts = $dsn;
+                $dsn = null;
+            }
+        }
+
+        // process the different protocol options
+        $parsed['protocol'] = (!empty($proto)) ? $proto : 'tcp';
+        $proto_opts = rawurldecode($proto_opts);
+        if (strpos($proto_opts, ':') !== false) {
+            list($proto_opts, $parsed['port']) = explode(':', $proto_opts);
+        }
+        if ($parsed['protocol'] == 'tcp') {
+            $parsed['hostspec'] = $proto_opts;
+        }
+        else if ($parsed['protocol'] == 'unix') {
+            $parsed['socket'] = $proto_opts;
+        }
+
+        // Get dabase if any
+        // $dsn => database
+        if ($dsn) {
+            // /database
+            if (($pos = strpos($dsn, '?')) === false) {
+                $parsed['database'] = rawurldecode($dsn);
+            // /database?param1=value1&param2=value2
+            }
+            else {
+                $parsed['database'] = rawurldecode(substr($dsn, 0, $pos));
+                $dsn = substr($dsn, $pos + 1);
+                if (strpos($dsn, '&') !== false) {
+                    $opts = explode('&', $dsn);
+                }
+                else { // database?param1=value1
+                    $opts = array($dsn);
+                }
+                foreach ($opts as $opt) {
+                    list($key, $value) = explode('=', $opt);
+                    if (!array_key_exists($key, $parsed) || false === $parsed[$key]) {
+                        // don't allow params overwrite
+                        $parsed[$key] = rawurldecode($value);
+                    }
+                }
+            }
+        }
+
+        return $parsed;
+    }
+
+    /**
+     * Returns PDO DSN string from DSN array
+     *
+     * @param array $dsn DSN parameters
+     *
+     * @return string DSN string
+     */
+    protected function dsn_string($dsn)
+    {
+        $params = array();
+        $result = $dsn['phptype'] . ':';
+
+        if ($dsn['hostspec']) {
+            $params[] = 'host=' . $dsn['hostspec'];
+        }
+
+        if ($dsn['port']) {
+            $params[] = 'port=' . $dsn['port'];
+        }
+
+        if ($dsn['database']) {
+            $params[] = 'dbname=' . $dsn['database'];
+        }
+
+        if (!empty($params)) {
+            $result .= implode(';', $params);
+        }
+
+        return $result;
+    }
+
+    /**
+     * Returns driver-specific connection options
+     *
+     * @param array $dsn DSN parameters
+     *
+     * @return array Connection options
+     */
+    protected function dsn_options($dsn)
+    {
+        $result = array();
+
+        return $result;
+    }
+}
diff --git a/program/include/rcube_db_mssql.php b/program/include/rcube_db_mssql.php
new file mode 100644
index 000000000..5cbcfab36
--- /dev/null
+++ b/program/include/rcube_db_mssql.php
@@ -0,0 +1,155 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_db_mssql.php                                    |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
+ |                                                                       |
+ | 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:                                                              |
+ |   Database wrapper class that implements PHP PDO functions            |
+ |   for MS SQL Server database                                          |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+
+/**
+ * Database independent query interface
+ *
+ * This is a wrapper for the PHP PDO
+ *
+ * @package Database
+ * @version 1.0
+ */
+class rcube_db_mssql extends rcube_db
+{
+    /**
+     * Driver initialization
+     */
+    protected function init()
+    {
+        $this->options['identifier_start'] = '[';
+        $this->options['identifier_end'] = ']';
+    }
+
+    /**
+     * Character setting
+     */
+    protected function set_charset($charset)
+    {
+        // UTF-8 is default
+    }
+
+    /**
+     * Return SQL function for current time and date
+     *
+     * @return string SQL function to use in query
+     */
+    public function now()
+    {
+        return "getdate()";
+    }
+
+    /**
+     * Return SQL statement to convert a field value into a unix timestamp
+     *
+     * This method is deprecated and should not be used anymore due to limitations
+     * of timestamp functions in Mysql (year 2038 problem)
+     *
+     * @param string $field Field name
+     *
+     * @return string SQL statement to use in query
+     * @deprecated
+     */
+    public function unixtimestamp($field)
+    {
+        return "DATEDIFF(second, '19700101', $field) + DATEDIFF(second, GETDATE(), GETUTCDATE())";
+    }
+
+    /**
+     * Abstract SQL statement for value concatenation
+     *
+     * @return string SQL statement to be used in query
+     */
+    public function concat(/* col1, col2, ... */)
+    {
+        $args = func_get_args();
+
+        if (is_array($args[0])) {
+            $args = $args[0];
+        }
+
+        return '(' . join('+', $args) . ')';
+    }
+
+    /**
+     * Adds TOP (LIMIT,OFFSET) clause to the query
+     *
+     * @param string $query  SQL query
+     * @param int    $limit  Number of rows
+     * @param int    $offset Offset
+     *
+     * @return string SQL query
+     */
+    protected function set_limit($query, $limit = 0, $offset = 0)
+    {
+        $limit  = intval($limit);
+        $offset = intval($offset);
+
+        $orderby = stristr($query, 'ORDER BY');
+        if ($orderby !== false) {
+            $sort  = (stripos($orderby, ' desc') !== false) ? 'desc' : 'asc';
+            $order = str_ireplace('ORDER BY', '', $orderby);
+            $order = trim(preg_replace('/\bASC\b|\bDESC\b/i', '', $order));
+        }
+
+        $query = preg_replace('/^SELECT\s/i', 'SELECT TOP ' . ($limit + $offset) . ' ', $query);
+
+        $query = 'SELECT * FROM (SELECT TOP ' . $limit . ' * FROM (' . $query . ') AS inner_tbl';
+        if ($orderby !== false) {
+            $query .= ' ORDER BY ' . $order . ' ';
+            $query .= (stripos($sort, 'asc') !== false) ? 'DESC' : 'ASC';
+        }
+        $query .= ') AS outer_tbl';
+        if ($orderby !== false) {
+            $query .= ' ORDER BY ' . $order . ' ' . $sort;
+        }
+
+        return $query;
+    }
+
+    /**
+     * Returns PDO DSN string from DSN array
+     */
+    protected function dsn_string($dsn)
+    {
+        $params = array();
+        $result = $dsn['phptype'] . ':';
+
+        if ($dsn['hostspec']) {
+            $host = $dsn['hostspec'];
+            if ($dsn['port']) {
+                $host .= ',' . $dsn['port'];
+            }
+            $params[] = 'host=' . $host;
+        }
+
+        if ($dsn['database']) {
+            $params[] = 'dbname=' . $dsn['database'];
+        }
+
+        if (!empty($params)) {
+            $result .= implode(';', $params);
+        }
+
+        return $result;
+    }
+}
diff --git a/program/include/rcube_db_mysql.php b/program/include/rcube_db_mysql.php
new file mode 100644
index 000000000..3606ec102
--- /dev/null
+++ b/program/include/rcube_db_mysql.php
@@ -0,0 +1,154 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_db_mysql.php                                    |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
+ |                                                                       |
+ | 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:                                                              |
+ |   Database wrapper class that implements PHP PDO functions            |
+ |   for MySQL database                                                  |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+
+/**
+ * Database independent query interface
+ *
+ * This is a wrapper for the PHP PDO
+ *
+ * @package Database
+ * @version 1.0
+ */
+class rcube_db_mysql extends rcube_db
+{
+    /**
+     * Driver initialization/configuration
+     */
+    protected function init()
+    {
+        // SQL identifiers quoting
+        $this->options['identifier_start'] = '`';
+        $this->options['identifier_end'] = '`';
+    }
+
+    /**
+     * Abstract SQL statement for value concatenation
+     *
+     * @return string SQL statement to be used in query
+     */
+    public function concat(/* col1, col2, ... */)
+    {
+        $args = func_get_args();
+
+        if (is_array($args[0])) {
+            $args = $args[0];
+        }
+
+        return 'CONCAT(' . join(', ', $args) . ')';
+    }
+
+    /**
+     * Returns PDO DSN string from DSN array
+     *
+     * @param array $dsn DSN parameters
+     *
+     * @return string Connection string
+     */
+    protected function dsn_string($dsn)
+    {
+        $params = array();
+        $result = 'mysql:';
+
+        if ($dsn['database']) {
+            $params[] = 'dbname=' . $dsn['database'];
+        }
+
+        if ($dsn['hostspec']) {
+            $params[] = 'host=' . $dsn['hostspec'];
+        }
+
+        if ($dsn['port']) {
+            $params[] = 'port=' . $dsn['port'];
+        }
+
+        if ($dsn['socket']) {
+            $params[] = 'unix_socket=' . $dsn['socket'];
+        }
+
+        $params[] = 'charset=utf8';
+
+        if (!empty($params)) {
+            $result .= implode(';', $params);
+        }
+
+        return $result;
+    }
+
+    /**
+     * Returns driver-specific connection options
+     *
+     * @param array $dsn DSN parameters
+     *
+     * @return array Connection options
+     */
+    protected function dsn_options($dsn)
+    {
+        $result = array();
+
+        if (!empty($dsn['key'])) {
+            $result[PDO::MYSQL_ATTR_KEY] = $dsn['key'];
+        }
+
+        if (!empty($dsn['cipher'])) {
+            $result[PDO::MYSQL_ATTR_CIPHER] = $dsn['cipher'];
+        }
+
+        if (!empty($dsn['cert'])) {
+            $result[PDO::MYSQL_ATTR_SSL_CERT] = $dsn['cert'];
+        }
+
+        if (!empty($dsn['capath'])) {
+            $result[PDO::MYSQL_ATTR_SSL_CAPATH] = $dsn['capath'];
+        }
+
+        if (!empty($dsn['ca'])) {
+            $result[PDO::MYSQL_ATTR_SSL_CA] = $dsn['ca'];
+        }
+
+        return $result;
+    }
+
+    /**
+     * Get database runtime variables
+     *
+     * @param string $varname Variable name
+     * @param mixed  $default Default value if variable is not set
+     *
+     * @return mixed Variable value or default
+     */
+    public function get_variable($varname, $default = null)
+    {
+        if (!isset($this->variables)) {
+            $this->variables = array();
+
+            $result = $this->query('SHOW VARIABLES');
+
+            while ($sql_arr = $this->fetch_array($result)) {
+                $this->variables[$row[0]] = $row[1];
+            }
+        }
+
+        return isset($this->variables[$varname]) ? $this->variables[$varname] : $default;
+    }
+
+}
diff --git a/program/include/rcube_db_pgsql.php b/program/include/rcube_db_pgsql.php
new file mode 100644
index 000000000..285b8e2d4
--- /dev/null
+++ b/program/include/rcube_db_pgsql.php
@@ -0,0 +1,135 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_db_pgsql.php                                    |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
+ |                                                                       |
+ | 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:                                                              |
+ |   Database wrapper class that implements PHP PDO functions            |
+ |   for PostgreSQL database                                             |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+
+/**
+ * Database independent query interface
+ *
+ * This is a wrapper for the PHP PDO
+ *
+ * @package Database
+ * @version 1.0
+ */
+class rcube_db_pgsql extends rcube_db
+{
+    /**
+     * Get last inserted record ID
+     *
+     * @param string $table Table name (to find the incremented sequence)
+     *
+     * @return mixed ID or false on failure
+     */
+    public function insert_id($table = null)
+    {
+        if (!$this->db_connected || $this->db_mode == 'r') {
+            return false;
+        }
+
+        if ($table) {
+            $table = $this->sequence_name($table);
+        }
+
+        $id = $this->dbh->lastInsertId($table);
+
+        return $id;
+    }
+
+    /**
+     * Return correct name for a specific database sequence
+     *
+     * @param string $sequence Secuence name
+     *
+     * @return string Translated sequence name
+     */
+    protected function sequence_name($sequence)
+    {
+        $rcube = rcube::get_instance();
+
+        // return sequence name if configured
+        $config_key = 'db_sequence_'.$sequence;
+
+        if ($name = $rcube->config->get($config_key)) {
+            return $name;
+        }
+
+        return $sequence;
+    }
+
+    /**
+     * Return SQL statement to convert a field value into a unix timestamp
+     *
+     * This method is deprecated and should not be used anymore due to limitations
+     * of timestamp functions in Mysql (year 2038 problem)
+     *
+     * @param string $field Field name
+     *
+     * @return string SQL statement to use in query
+     * @deprecated
+     */
+    public function unixtimestamp($field)
+    {
+        return "EXTRACT (EPOCH FROM $field)";
+    }
+
+    /**
+     * Return SQL statement for case insensitive LIKE
+     *
+     * @param string $column Field name
+     * @param string $value  Search value
+     *
+     * @return string SQL statement to use in query
+     */
+    public function ilike($column, $value)
+    {
+        return $this->quote_identifier($column) . ' ILIKE ' . $this->quote($value);
+    }
+
+    /**
+     * Get database runtime variables
+     *
+     * @param string $varname Variable name
+     * @param mixed  $default Default value if variable is not set
+     *
+     * @return mixed Variable value or default
+     */
+    public function get_variable($varname, $default = null)
+    {
+        // There's a known case when max_allowed_packet is queried
+        // PostgreSQL doesn't have such limit, return immediately
+        if ($varname == 'max_allowed_packet') {
+            return $default;
+        }
+
+        if (!isset($this->variables)) {
+            $this->variables = array();
+
+            $result = $this->query('SHOW ALL');
+
+            while ($row = $this->fetch_array($result)) {
+                $this->variables[$row[0]] = $row[1];
+            }
+        }
+
+        return isset($this->variables[$varname]) ? $this->variables[$varname] : $default;
+    }
+
+}
diff --git a/program/include/rcube_db_sqlite.php b/program/include/rcube_db_sqlite.php
new file mode 100644
index 000000000..a9774cd51
--- /dev/null
+++ b/program/include/rcube_db_sqlite.php
@@ -0,0 +1,178 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_db_sqlite.php                                   |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
+ |                                                                       |
+ | Licensed under the GNU General Public License version 3 or            |
+ | any later version with exceptions for skins & plugins.                |
+ | See the README file for a full license statement.                     |
+ |                                                                       |
+ | PURPOSE:                                                              |
+ |   Database wrapper class that implements PHP PDO functions            |
+ |   for SQLite database                                                 |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+
+/**
+ * Database independent query interface
+ *
+ * This is a wrapper for the PHP PDO
+ *
+ * @package Database
+ * @version 1.0
+ */
+class rcube_db_sqlite extends rcube_db
+{
+    /**
+     * Database character set
+     */
+    protected function set_charset($charset)
+    {
+    }
+
+    /**
+     * Prepare connection
+     */
+    protected function conn_prepare($dsn)
+    {
+        // Create database file, required by PDO to exist on connection
+        if (!empty($dsn['database']) && !file_exists($dsn['database'])) {
+            $created = touch($dsn['database']);
+
+            // File mode setting, for compat. with MDB2
+            if (!empty($dsn['mode']) && $created) {
+                chmod($dsn['database'], octdec($dsn['mode']));
+            }
+        }
+    }
+
+    /**
+     * Configure connection, create database if not exists
+     */
+    protected function conn_configure($dsn, $dbh)
+    {
+        // we emulate via callback some missing functions
+        $dbh->sqliteCreateFunction('unix_timestamp', array('rcube_db_sqlite', 'sqlite_unix_timestamp'), 1);
+        $dbh->sqliteCreateFunction('now', array('rcube_db_sqlite', 'sqlite_now'), 0);
+
+        // Initialize database structure in file is empty
+        if (!empty($dsn['database']) && !filesize($dsn['database'])) {
+            $data = file_get_contents(INSTALL_PATH . 'SQL/sqlite.initial.sql');
+
+            if (strlen($data)) {
+                $this->debug('INITIALIZE DATABASE');
+
+                $q = $dbh->exec($data);
+
+                if ($q === false) {
+                    $error = $dbh->errorInfo();
+                    $this->db_error = true;
+                    $this->db_error_msg = sprintf('[%s] %s', $error[1], $error[2]);
+
+                    rcube::raise_error(array('code' => 500, 'type' => 'db',
+                        'line' => __LINE__, 'file' => __FILE__,
+                        'message' => $this->db_error_msg), true, false);
+                }
+            }
+        }
+    }
+
+    /**
+     * Callback for sqlite: unix_timestamp()
+     */
+    public static function sqlite_unix_timestamp($timestamp = '')
+    {
+        $timestamp = trim($timestamp);
+        if (!$timestamp) {
+            $ret = time();
+        }
+        else if (!preg_match('/^[0-9]+$/s', $timestamp)) {
+            $ret = strtotime($timestamp);
+        }
+        else {
+            $ret = $timestamp;
+        }
+
+        return $ret;
+    }
+
+    /**
+     * Callback for sqlite: now()
+     */
+    public static function sqlite_now()
+    {
+        return date("Y-m-d H:i:s");
+    }
+
+    /**
+     * Returns list of tables in database
+     *
+     * @return array List of all tables of the current database
+     */
+    public function list_tables()
+    {
+        if ($this->tables === null) {
+            $q = $this->query('SELECT name FROM sqlite_master'
+                .' WHERE type = \'table\' ORDER BY name');
+
+            if ($res = $this->_get_result($q)) {
+                $this->tables = $res->fetchAll(PDO::FETCH_COLUMN, 0);
+            }
+            else {
+                $this->tables = array();
+            }
+        }
+
+        return $this->tables;
+    }
+
+    /**
+     * Returns list of columns in database table
+     *
+     * @param string $table Table name
+     *
+     * @return array List of table cols
+     */
+    public function list_cols($table)
+    {
+        $q = $this->query('SELECT sql FROM sqlite_master WHERE type = ? AND name = ?',
+            array('table', $table));
+
+        $columns = array();
+
+        if ($sql = $this->fetch_array($q)) {
+            $sql       = $sql[0];
+            $start_pos = strpos($sql, '(');
+            $end_pos   = strrpos($sql, ')');
+            $sql       = substr($sql, $start_pos+1, $end_pos-$start_pos-1);
+            $lines     = explode(',', $sql);
+
+            foreach ($lines as $line) {
+                $line = explode(' ', trim($line));
+
+                if ($line[0] && strpos($line[0], '--') !== 0) {
+                    $column = $line[0];
+                    $columns[] = trim($column, '"');
+                }
+            }
+        }
+
+        return $columns;
+    }
+
+    /**
+     * Build DSN string for PDO constructor
+     */
+    protected function dsn_string($dsn)
+    {
+        return $dsn['phptype'] . ':' . $dsn['database'];
+    }
+}
diff --git a/program/include/rcube_db_sqlsrv.php b/program/include/rcube_db_sqlsrv.php
new file mode 100644
index 000000000..feddbe73f
--- /dev/null
+++ b/program/include/rcube_db_sqlsrv.php
@@ -0,0 +1,156 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_db_sqlsrv.php                                   |
+ |                                                                       |
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2005-2012, The Roundcube Dev Team                       |
+ |                                                                       |
+ | 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:                                                              |
+ |   Database wrapper class that implements PHP PDO functions            |
+ |   for MS SQL Server database                                          |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+
+/**
+ * Database independent query interface
+ *
+ * This is a wrapper for the PHP PDO
+ *
+ * @package Database
+ * @version 1.0
+ */
+class rcube_db_sqlsrv extends rcube_db
+{
+    /**
+     * Driver initialization
+     */
+    protected function init()
+    {
+        $this->options['identifier_start'] = '[';
+        $this->options['identifier_end'] = ']';
+    }
+
+    /**
+     * Database character set setting
+     */
+    protected function set_charset($charset)
+    {
+        // UTF-8 is default
+    }
+
+    /**
+     * Return SQL function for current time and date
+     *
+     * @return string SQL function to use in query
+     */
+    public function now()
+    {
+        return "getdate()";
+    }
+
+    /**
+     * Return SQL statement to convert a field value into a unix timestamp
+     *
+     * This method is deprecated and should not be used anymore due to limitations
+     * of timestamp functions in Mysql (year 2038 problem)
+     *
+     * @param string $field Field name
+     *
+     * @return string SQL statement to use in query
+     * @deprecated
+     */
+    public function unixtimestamp($field)
+    {
+        return "DATEDIFF(second, '19700101', $field) + DATEDIFF(second, GETDATE(), GETUTCDATE())";
+    }
+
+    /**
+     * Abstract SQL statement for value concatenation
+     *
+     * @return string SQL statement to be used in query
+     */
+    public function concat(/* col1, col2, ... */)
+    {
+        $args = func_get_args();
+
+        if (is_array($args[0])) {
+            $args = $args[0];
+        }
+
+        return '(' . join('+', $args) . ')';
+    }
+
+    /**
+     * Adds TOP (LIMIT,OFFSET) clause to the query
+     *
+     * @param string $query  SQL query
+     * @param int    $limit  Number of rows
+     * @param int    $offset Offset
+     *
+     * @return string SQL query
+     */
+    protected function set_limit($query, $limit = 0, $offset = 0)
+    {
+        $limit  = intval($limit);
+        $offset = intval($offset);
+
+        $orderby = stristr($query, 'ORDER BY');
+        if ($orderby !== false) {
+            $sort  = (stripos($orderby, ' desc') !== false) ? 'desc' : 'asc';
+            $order = str_ireplace('ORDER BY', '', $orderby);
+            $order = trim(preg_replace('/\bASC\b|\bDESC\b/i', '', $order));
+        }
+
+        $query = preg_replace('/^SELECT\s/i', 'SELECT TOP ' . ($limit + $offset) . ' ', $query);
+
+        $query = 'SELECT * FROM (SELECT TOP ' . $limit . ' * FROM (' . $query . ') AS inner_tbl';
+        if ($orderby !== false) {
+            $query .= ' ORDER BY ' . $order . ' ';
+            $query .= (stripos($sort, 'asc') !== false) ? 'DESC' : 'ASC';
+        }
+        $query .= ') AS outer_tbl';
+        if ($orderby !== false) {
+            $query .= ' ORDER BY ' . $order . ' ' . $sort;
+        }
+
+        return $query;
+    }
+
+    /**
+     * Returns PDO DSN string from DSN array
+     */
+    protected function dsn_string($dsn)
+    {
+        $params = array();
+        $result = 'sqlsrv:';
+
+        if ($dsn['hostspec']) {
+            $host = $dsn['hostspec'];
+
+            if ($dsn['port']) {
+                $host .= ',' . $dsn['port'];
+            }
+            $params[] = 'Server=' . $host;
+        }
+
+        if ($dsn['database']) {
+            $params[] = 'Database=' . $dsn['database'];
+        }
+
+        if (!empty($params)) {
+            $result .= implode(';', $params);
+        }
+
+        return $result;
+    }
+}
diff --git a/program/include/rcube_imap_cache.php b/program/include/rcube_imap_cache.php
index 530284a58..a061a1f6e 100644
--- a/program/include/rcube_imap_cache.php
+++ b/program/include/rcube_imap_cache.php
@@ -39,9 +39,9 @@ class rcube_imap_cache
     private $imap;
 
     /**
-     * Instance of rcube_mdb2
+     * Instance of rcube_db
      *
-     * @var rcube_mdb2
+     * @var rcube_db
      */
     private $db;
 
diff --git a/program/include/rcube_mdb2.php b/program/include/rcube_mdb2.php
deleted file mode 100644
index 721963b4c..000000000
--- a/program/include/rcube_mdb2.php
+++ /dev/null
@@ -1,935 +0,0 @@
-<?php
-
-/*
- +-----------------------------------------------------------------------+
- | program/include/rcube_mdb2.php                                        |
- |                                                                       |
- | This file is part of the Roundcube Webmail client                     |
- | Copyright (C) 2005-2009, The Roundcube Dev Team                       |
- |                                                                       |
- | 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:                                                              |
- |   PEAR:DB wrapper class that implements PEAR MDB2 functions           |
- |   See http://pear.php.net/package/MDB2                                |
- |                                                                       |
- +-----------------------------------------------------------------------+
- | Author: Lukas Kahwe Smith <smith@pooteeweet.org>                      |
- +-----------------------------------------------------------------------+
-*/
-
-
-/**
- * Database independent query interface
- *
- * This is a wrapper for the PEAR::MDB2 class
- *
- * @package    Database
- * @author     David Saez Padros <david@ols.es>
- * @author     Thomas Bruederli <roundcube@gmail.com>
- * @author     Lukas Kahwe Smith <smith@pooteeweet.org>
- * @version    1.18
- * @link       http://pear.php.net/package/MDB2
- */
-class rcube_mdb2
-{
-    public $db_dsnw;               // DSN for write operations
-    public $db_dsnr;               // DSN for read operations
-    public $db_connected = false;  // Already connected ?
-    public $db_mode = '';          // Connection mode
-    public $db_handle = 0;         // Connection handle
-    public $db_error = false;
-    public $db_error_msg = '';
-
-    private $debug_mode = false;
-    private $conn_failure = false;
-    private $a_query_results = array('dummy');
-    private $last_res_id = 0;
-    private $tables;
-    private $variables;
-
-
-    /**
-     * Object constructor
-     *
-     * @param  string $db_dsnw DSN for read/write operations
-     * @param  string $db_dsnr Optional DSN for read only operations
-     */
-    public function __construct($db_dsnw, $db_dsnr='', $pconn=false)
-    {
-        if (empty($db_dsnr)) {
-            $db_dsnr = $db_dsnw;
-        }
-
-        $this->db_dsnw = $db_dsnw;
-        $this->db_dsnr = $db_dsnr;
-        $this->db_pconn = $pconn;
-
-        $dsn_array = MDB2::parseDSN($db_dsnw);
-        $this->db_provider = $dsn_array['phptype'];
-    }
-
-
-    /**
-     * Connect to specific database
-     *
-     * @param  string $dsn  DSN for DB connections
-     * @return MDB2 PEAR database handle
-     * @access private
-     */
-    private function dsn_connect($dsn)
-    {
-        // Use persistent connections if available
-        $db_options = array(
-            'persistent'       => $this->db_pconn,
-            'emulate_prepared' => $this->debug_mode,
-            'debug'            => $this->debug_mode,
-            'debug_handler'    => array($this, 'debug_handler'),
-            'portability'      => MDB2_PORTABILITY_ALL ^ MDB2_PORTABILITY_EMPTY_TO_NULL,
-        );
-
-        if ($this->db_provider == 'pgsql') {
-            $db_options['disable_smart_seqname'] = true;
-            $db_options['seqname_format'] = '%s';
-        }
-        $this->db_error     = false;
-        $this->db_error_msg = null;
-
-        $dbh = MDB2::connect($dsn, $db_options);
-
-        if (MDB2::isError($dbh)) {
-            $this->db_error = true;
-            $this->db_error_msg = $dbh->getMessage();
-
-            rcube::raise_error(array('code' => 500, 'type' => 'db',
-                'line' => __LINE__, 'file' => __FILE__,
-                'message' => $dbh->getUserInfo()), true, false);
-        }
-        else if ($this->db_provider == 'sqlite') {
-            $dsn_array = MDB2::parseDSN($dsn);
-            if (!filesize($dsn_array['database']) && !empty($this->sqlite_initials)) {
-                $this->sqlite_create_database($dbh, $this->sqlite_initials);
-            }
-        }
-        else if ($this->db_provider != 'mssql' && $this->db_provider != 'sqlsrv') {
-            $dbh->setCharset('utf8');
-        }
-
-        return $dbh;
-    }
-
-
-    /**
-     * Connect to appropiate database depending on the operation
-     *
-     * @param  string $mode Connection mode (r|w)
-     */
-    public function db_connect($mode)
-    {
-        // previous connection failed, don't attempt to connect again
-        if ($this->conn_failure) {
-            return;
-        }
-
-        // no replication
-        if ($this->db_dsnw == $this->db_dsnr) {
-            $mode = 'w';
-        }
-
-        // Already connected
-        if ($this->db_connected) {
-            // connected to db with the same or "higher" mode
-            if ($this->db_mode == 'w' || $this->db_mode == $mode) {
-                return;
-            }
-        }
-
-        $dsn = ($mode == 'r') ? $this->db_dsnr : $this->db_dsnw;
-
-        $this->db_handle    = $this->dsn_connect($dsn);
-        $this->db_connected = !PEAR::isError($this->db_handle);
-
-        // use write-master when read-only fails
-        if (!$this->db_connected && $mode == 'r') {
-            $mode = 'w';
-            $this->db_handle    = $this->dsn_connect($this->db_dsnw);
-            $this->db_connected = !PEAR::isError($this->db_handle);
-        }
-
-        if ($this->db_connected) {
-            $this->db_mode = $mode;
-        }
-        else {
-            $this->conn_failure = true;
-        }
-    }
-
-
-    /**
-     * Activate/deactivate debug mode
-     *
-     * @param boolean $dbg True if SQL queries should be logged
-     */
-    public function set_debug($dbg = true)
-    {
-        $this->debug_mode = $dbg;
-        if ($this->db_connected) {
-            $this->db_handle->setOption('debug', $dbg);
-            $this->db_handle->setOption('emulate_prepared', $dbg);
-        }
-    }
-
-
-    /**
-     * Getter for error state
-     *
-     * @param  boolean  True on error
-     */
-    public function is_error()
-    {
-        return $this->db_error ? $this->db_error_msg : false;
-    }
-
-
-    /**
-     * Connection state checker
-     *
-     * @param  boolean  True if in connected state
-     */
-    public function is_connected()
-    {
-        return PEAR::isError($this->db_handle) ? false : $this->db_connected;
-    }
-
-
-    /**
-     * Is database replication configured?
-     * This returns true if dsnw != dsnr
-     */
-    public function is_replicated()
-    {
-      return !empty($this->db_dsnr) && $this->db_dsnw != $this->db_dsnr;
-    }
-
-
-    /**
-     * Get database runtime variables
-     *
-     * @param string Variable name
-     * @param mixed  Default value if var is not set
-     * @return mixed Variable value or default
-     */
-    public function get_variable($varname, $default = null)
-    {
-        if (!isset($this->variables)) {
-            $this->variables = array();
-
-            // only mysql and postgres are know to support this
-            if ($this->db_provider == 'pgsql' || $this->db_provider == 'mysql' || $this->db_provider == 'mysqli') {
-                $this->db_connect('r');
-                $query = $this->db_provider == 'pgsql' ? 'SHOW ALL' : 'SHOW VARIABLES';
-                foreach ((array)$this->db_handle->queryAll($query) as $row)
-                    $this->variables[$row[0]] = $row[1];
-            }
-        }
-
-        return isset($this->variables[$varname]) ? $this->variables[$varname] : $default;
-    }
-
-
-    /**
-     * Execute a SQL query
-     *
-     * @param  string  SQL query to execute
-     * @param  mixed   Values to be inserted in query
-     *
-     * @return number  Query handle identifier
-     */
-    public function query()
-    {
-        $params = func_get_args();
-        $query = array_shift($params);
-
-        // Support one argument of type array, instead of n arguments
-        if (count($params) == 1 && is_array($params[0])) {
-            $params = $params[0];
-        }
-
-        return $this->_query($query, 0, 0, $params);
-    }
-
-
-    /**
-     * Execute a SQL query with limits
-     *
-     * @param  string  SQL query to execute
-     * @param  number  Offset for LIMIT statement
-     * @param  number  Number of rows for LIMIT statement
-     * @param  mixed   Values to be inserted in query
-     *
-     * @return number  Query handle identifier
-     */
-    public function limitquery()
-    {
-        $params  = func_get_args();
-        $query   = array_shift($params);
-        $offset  = array_shift($params);
-        $numrows = array_shift($params);
-
-        return $this->_query($query, $offset, $numrows, $params);
-    }
-
-
-    /**
-     * Execute a SQL query with limits
-     *
-     * @param  string $query   SQL query to execute
-     * @param  number $offset  Offset for LIMIT statement
-     * @param  number $numrows Number of rows for LIMIT statement
-     * @param  array  $params  Values to be inserted in query
-     * @return number  Query handle identifier
-     * @access private
-     */
-    private function _query($query, $offset, $numrows, $params)
-    {
-        // Read or write ?
-        $mode = (strtolower(substr(trim($query),0,6)) == 'select') ? 'r' : 'w';
-
-        $this->db_connect($mode);
-
-        // check connection before proceeding
-        if (!$this->is_connected()) {
-            return null;
-        }
-
-        if ($this->db_provider == 'sqlite') {
-            $this->sqlite_prepare();
-        }
-
-        if ($numrows || $offset) {
-            $result = $this->db_handle->setLimit($numrows,$offset);
-        }
-
-        if (empty($params)) {
-            $result = $mode == 'r' ? $this->db_handle->query($query) : $this->db_handle->exec($query);
-        }
-        else {
-            $params = (array)$params;
-            $q = $this->db_handle->prepare($query, null, $mode=='w' ? MDB2_PREPARE_MANIP : null);
-            if ($this->db_handle->isError($q)) {
-                $this->db_error = true;
-                $this->db_error_msg = $q->userinfo;
-
-                rcube::raise_error(array('code' => 500, 'type' => 'db',
-                    'line' => __LINE__, 'file' => __FILE__,
-                    'message' => $this->db_error_msg), true, false);
-
-                $result = false;
-            }
-            else {
-                $result = $q->execute($params);
-                $q->free();
-            }
-        }
-
-        // add result, even if it's an error
-        return $this->_add_result($result);
-    }
-
-
-    /**
-     * Get number of rows for a SQL query
-     * If no query handle is specified, the last query will be taken as reference
-     *
-     * @param  number $res_id  Optional query handle identifier
-     * @return mixed   Number of rows or false on failure
-     */
-    public function num_rows($res_id=null)
-    {
-        if (!$this->db_connected) {
-            return false;
-        }
-
-        if ($result = $this->_get_result($res_id)) {
-            return $result->numRows();
-        }
-
-        return false;
-    }
-
-
-    /**
-     * Get number of affected rows for the last query
-     *
-     * @param  number $res_id Optional query handle identifier
-     * @return mixed   Number of rows or false on failure
-     */
-    public function affected_rows($res_id = null)
-    {
-        if (!$this->db_connected) {
-            return false;
-        }
-
-        return $this->_get_result($res_id);
-    }
-
-
-    /**
-     * Get last inserted record ID
-     * For Postgres databases, a sequence name is required
-     *
-     * @param  string $table  Table name (to find the incremented sequence)
-     *
-     * @return mixed   ID or false on failure
-     */
-    public function insert_id($table = '')
-    {
-        if (!$this->db_connected || $this->db_mode == 'r') {
-            return false;
-        }
-
-        if ($table) {
-            if ($this->db_provider == 'pgsql') {
-                // find sequence name
-                $table = $this->sequence_name($table);
-            }
-            else {
-                // resolve table name
-                $table = $this->table_name($table);
-            }
-        }
-
-        $id = $this->db_handle->lastInsertID($table);
-
-        return $this->db_handle->isError($id) ? null : $id;
-    }
-
-
-    /**
-     * Get an associative array for one row
-     * If no query handle is specified, the last query will be taken as reference
-     *
-     * @param  number $res_id Optional query handle identifier
-     *
-     * @return mixed   Array with col values or false on failure
-     */
-    public function fetch_assoc($res_id = null)
-    {
-        $result = $this->_get_result($res_id);
-        return $this->_fetch_row($result, MDB2_FETCHMODE_ASSOC);
-    }
-
-
-    /**
-     * Get an index array for one row
-     * If no query handle is specified, the last query will be taken as reference
-     *
-     * @param  number $res_id  Optional query handle identifier
-     *
-     * @return mixed   Array with col values or false on failure
-     */
-    public function fetch_array($res_id = null)
-    {
-        $result = $this->_get_result($res_id);
-        return $this->_fetch_row($result, MDB2_FETCHMODE_ORDERED);
-    }
-
-
-    /**
-     * Get col values for a result row
-     *
-     * @param  MDB2_Result_Common Query $result result handle
-     * @param  number                   $mode   Fetch mode identifier
-     *
-     * @return mixed  Array with col values or false on failure
-     */
-    private function _fetch_row($result, $mode)
-    {
-        if ($result === false || PEAR::isError($result) || !$this->is_connected()) {
-            return false;
-        }
-
-        return $result->fetchRow($mode);
-    }
-
-
-    /**
-     * Wrapper for the SHOW TABLES command
-     *
-     * @return array List of all tables of the current database
-     * @since 0.4-beta
-     */
-    public function list_tables()
-    {
-        // get tables if not cached
-        if (!$this->tables) {
-            $this->db_handle->loadModule('Manager');
-            if (!PEAR::isError($result = $this->db_handle->listTables())) {
-                $this->tables = $result;
-            }
-            else {
-                $this->tables = array();
-            }
-        }
-
-        return $this->tables;
-    }
-
-
-    /**
-     * Wrapper for SHOW COLUMNS command
-     *
-     * @param string Table name
-     *
-     * @return array List of table cols
-     */
-    public function list_cols($table)
-    {
-        $this->db_handle->loadModule('Manager');
-        if (!PEAR::isError($result = $this->db_handle->listTableFields($table))) {
-            return $result;
-        }
-
-        return null;
-    }
-
-
-    /**
-     * Formats input so it can be safely used in a query
-     *
-     * @param  mixed  $input  Value to quote
-     * @param  string $type   Type of data
-     *
-     * @return string  Quoted/converted string for use in query
-     */
-    public function quote($input, $type = null)
-    {
-        // handle int directly for better performance
-        if ($type == 'integer') {
-            return intval($input);
-        }
-
-        // create DB handle if not available
-        if (!$this->db_handle) {
-            $this->db_connect('r');
-        }
-
-        return $this->db_connected ? $this->db_handle->quote($input, $type) : addslashes($input);
-    }
-
-
-    /**
-     * Quotes a string so it can be safely used as a table or column name
-     *
-     * @param  string $str Value to quote
-     *
-     * @return string  Quoted string for use in query
-     * @deprecated     Replaced by rcube_MDB2::quote_identifier
-     * @see            rcube_mdb2::quote_identifier
-     */
-    public function quoteIdentifier($str)
-    {
-        return $this->quote_identifier($str);
-    }
-
-
-    /**
-     * Quotes a string so it can be safely used as a table or column name
-     *
-     * @param  string $str Value to quote
-     *
-     * @return string  Quoted string for use in query
-     */
-    public function quote_identifier($str)
-    {
-        if (!$this->db_handle) {
-            $this->db_connect('r');
-        }
-
-        return $this->db_connected ? $this->db_handle->quoteIdentifier($str) : $str;
-    }
-
-
-    /**
-     * Escapes a string
-     *
-     * @param  string $str The string to be escaped
-     *
-     * @return string  The escaped string
-     * @since  0.1.1
-     */
-    public function escapeSimple($str)
-    {
-        if (!$this->db_handle) {
-            $this->db_connect('r');
-        }
-
-        return $this->db_handle->escape($str);
-    }
-
-
-    /**
-     * Return SQL function for current time and date
-     *
-     * @return string SQL function to use in query
-     */
-    public function now()
-    {
-        switch ($this->db_provider) {
-            case 'mssql':
-            case 'sqlsrv':
-                return "getdate()";
-
-            default:
-                return "now()";
-        }
-    }
-
-
-    /**
-     * Return list of elements for use with SQL's IN clause
-     *
-     * @param  array  $arr  Input array
-     * @param  string $type Type of data
-     *
-     * @return string Comma-separated list of quoted values for use in query
-     */
-    public function array2list($arr, $type = null)
-    {
-        if (!is_array($arr)) {
-            return $this->quote($arr, $type);
-        }
-
-        foreach ($arr as $idx => $item) {
-            $arr[$idx] = $this->quote($item, $type);
-        }
-
-        return implode(',', $arr);
-    }
-
-
-    /**
-     * Return SQL statement to convert a field value into a unix timestamp
-     *
-     * This method is deprecated and should not be used anymore due to limitations
-     * of timestamp functions in Mysql (year 2038 problem)
-     *
-     * @param  string $field Field name
-     *
-     * @return string  SQL statement to use in query
-     * @deprecated
-     */
-    public function unixtimestamp($field)
-    {
-        switch($this->db_provider) {
-            case 'pgsql':
-                return "EXTRACT (EPOCH FROM $field)";
-
-            case 'mssql':
-            case 'sqlsrv':
-                return "DATEDIFF(second, '19700101', $field) + DATEDIFF(second, GETDATE(), GETUTCDATE())";
-
-            default:
-                return "UNIX_TIMESTAMP($field)";
-        }
-    }
-
-
-    /**
-     * Return SQL statement to convert from a unix timestamp
-     *
-     * @param  string $timestamp Field name
-     *
-     * @return string  SQL statement to use in query
-     */
-    public function fromunixtime($timestamp)
-    {
-        return date("'Y-m-d H:i:s'", $timestamp);
-    }
-
-
-    /**
-     * Return SQL statement for case insensitive LIKE
-     *
-     * @param  string $column  Field name
-     * @param  string $value   Search value
-     *
-     * @return string  SQL statement to use in query
-     */
-    public function ilike($column, $value)
-    {
-        // TODO: use MDB2's matchPattern() function
-        switch ($this->db_provider) {
-            case 'pgsql':
-                return $this->quote_identifier($column).' ILIKE '.$this->quote($value);
-            default:
-                return $this->quote_identifier($column).' LIKE '.$this->quote($value);
-        }
-    }
-
-
-    /**
-     * Abstract SQL statement for value concatenation
-     *
-     * @return string SQL statement to be used in query
-     */
-    public function concat(/* col1, col2, ... */)
-    {
-        $func = '';
-        $args = func_get_args();
-        if (is_array($args[0]))
-            $args = $args[0];
-
-        switch ($this->db_provider) {
-            case 'mysql':
-            case 'mysqli':
-                $func = 'CONCAT';
-                $delim = ', ';
-                break;
-            case 'mssql':
-            case 'sqlsrv':
-                $delim = ' + ';
-                // Modify arguments, because + operator requires them to be of type varchar (#1488505)
-                // with SQL Server 2012 we can use just CONCAT(), but we need to support older versions
-                foreach ($args as $idx => $arg) {
-                    $args[$idx] = "CAST($arg AS varchar)";
-                }
-                break;
-            default:
-                $delim = ' || ';
-        }
-
-        return $func . '(' . join($delim, $args) . ')';
-    }
-
-
-    /**
-     * Encodes non-UTF-8 characters in string/array/object (recursive)
-     *
-     * @param  mixed  $input Data to fix
-     *
-     * @return mixed  Properly UTF-8 encoded data
-     */
-    public static function encode($input)
-    {
-        if (is_object($input)) {
-            foreach (get_object_vars($input) as $idx => $value) {
-                $input->$idx = self::encode($value);
-            }
-            return $input;
-        }
-        else if (is_array($input)) {
-            foreach ($input as $idx => $value) {
-                $input[$idx] = self::encode($value);
-            }
-            return $input;
-        }
-
-        return utf8_encode($input);
-    }
-
-
-    /**
-     * Decodes encoded UTF-8 string/object/array (recursive)
-     *
-     * @param  mixed $input Input data
-     *
-     * @return mixed  Decoded data
-     */
-    public static function decode($input)
-    {
-        if (is_object($input)) {
-            foreach (get_object_vars($input) as $idx => $value) {
-                $input->$idx = self::decode($value);
-            }
-            return $input;
-        }
-        else if (is_array($input)) {
-            foreach ($input as $idx => $value) {
-                $input[$idx] = self::decode($value);
-            }
-            return $input;
-        }
-
-        return utf8_decode($input);
-    }
-
-
-    /**
-     * Adds a query result and returns a handle ID
-     *
-     * @param  object $res Query handle
-     *
-     * @return mixed   Handle ID
-     */
-    private function _add_result($res)
-    {
-        // sql error occured
-        if (PEAR::isError($res)) {
-            $this->db_error = true;
-            $this->db_error_msg = $res->getMessage();
-            rcube::raise_error(array('code' => 500, 'type' => 'db',
-                'line' => __LINE__, 'file' => __FILE__,
-                'message' => $res->getMessage() . " Query: " 
-                . substr(preg_replace('/[\r\n]+\s*/', ' ', $res->userinfo), 0, 512)),
-                true, false);
-        }
-
-        $res_id = sizeof($this->a_query_results);
-        $this->last_res_id = $res_id;
-        $this->a_query_results[$res_id] = $res;
-        return $res_id;
-    }
-
-
-    /**
-     * Resolves a given handle ID and returns the according query handle
-     * If no ID is specified, the last resource handle will be returned
-     *
-     * @param  number $res_id Handle ID
-     *
-     * @return mixed   Resource handle or false on failure
-     */
-    private function _get_result($res_id = null)
-    {
-        if ($res_id == null) {
-            $res_id = $this->last_res_id;
-        }
-
-        if (isset($this->a_query_results[$res_id])) {
-            if (!PEAR::isError($this->a_query_results[$res_id])) {
-                return $this->a_query_results[$res_id];
-            }
-        }
-
-        return false;
-    }
-
-
-    /**
-     * Create a sqlite database from a file
-     *
-     * @param  MDB2   $dbh       SQLite database handle
-     * @param  string $file_name File path to use for DB creation
-     */
-    private function sqlite_create_database($dbh, $file_name)
-    {
-        if (empty($file_name) || !is_string($file_name)) {
-            return;
-        }
-
-        $data = file_get_contents($file_name);
-
-        if (strlen($data)) {
-            if (!sqlite_exec($dbh->connection, $data, $error) || MDB2::isError($dbh)) {
-                rcube::raise_error(array('code' => 500, 'type' => 'db',
-                    'line' => __LINE__, 'file' => __FILE__,
-                    'message' => $error), true, false);
-            }
-        }
-    }
-
-
-    /**
-     * Add some proprietary database functions to the current SQLite handle
-     * in order to make it MySQL compatible
-     */
-    private function sqlite_prepare()
-    {
-        // we emulate via callback some missing MySQL functions
-        sqlite_create_function($this->db_handle->connection,
-            'unix_timestamp', array('rcube_mdb2', 'sqlite_unix_timestamp'));
-        sqlite_create_function($this->db_handle->connection,
-            'now', array('rcube_mdb2', 'sqlite_now'));
-    }
-
-
-    /**
-     * Debug handler for the MDB2
-     */
-    function debug_handler(&$db, $scope, $message, $context = array())
-    {
-        if ($scope != 'prepare') {
-            $debug_output = sprintf('%s(%d): %s;',
-                $scope, $db->db_index, rtrim($message, ';'));
-            rcube::write_log('sql', $debug_output);
-        }
-    }
-
-
-    /**
-     * Return correct name for a specific database table
-     *
-     * @param string $table Table name
-     *
-     * @return string Translated table name
-     */
-    public function table_name($table)
-    {
-        $rcube = rcube::get_instance();
-
-        // return table name if configured
-        $config_key = 'db_table_'.$table;
-
-        if ($name = $rcube->config->get($config_key)) {
-            return $name;
-        }
-
-        return $table;
-    }
-
-
-    /**
-     * Return correct name for a specific database sequence
-     * (used for Postgres only)
-     *
-     * @param string $sequence Secuence name
-     *
-     * @return string Translated sequence name
-     */
-    public function sequence_name($sequence)
-    {
-        $rcube = rcube::get_instance();
-
-        // return sequence name if configured
-        $config_key = 'db_sequence_'.$sequence;
-
-        if ($name = $rcube->config->get($config_key)) {
-            return $name;
-        }
-
-        return $sequence;
-    }
-
-
-    /**
-     * Callback for sqlite: unix_timestamp()
-     */
-    public static function sqlite_unix_timestamp($timestamp = '')
-    {
-        $timestamp = trim($timestamp);
-        if (!$timestamp) {
-            $ret = time();
-        }
-        else if (!preg_match('/^[0-9]+$/s', $timestamp)) {
-            $ret = strtotime($timestamp);
-        }
-        else {
-            $ret = $timestamp;
-        }
-
-        return $ret;
-    }
-
-
-    /**
-     * Callback for sqlite: now()
-     */
-    public static function sqlite_now()
-    {
-        return date("Y-m-d H:i:s");
-    }
-
-}
diff --git a/program/include/rcube_shared.inc b/program/include/rcube_shared.inc
index 08fca48dc..85f278432 100644
--- a/program/include/rcube_shared.inc
+++ b/program/include/rcube_shared.inc
@@ -407,7 +407,7 @@ function rcube_autoload($classname)
             '/^utf8$/',
         ),
         array(
-            'MDB2/\\1',
+            'Mail/\\1',
             'Mail/\\1',
             'Net/\\1',
             'Auth/\\1',
diff --git a/program/include/rcube_user.php b/program/include/rcube_user.php
index a54cbd79c..644d24bd9 100644
--- a/program/include/rcube_user.php
+++ b/program/include/rcube_user.php
@@ -36,7 +36,7 @@ class rcube_user
     /**
      * Holds database connection.
      *
-     * @var rcube_mdb2
+     * @var rcube_db
      */
     private $db;