diff --git a/program/lib/Roundcube/rcube_db.php b/program/lib/Roundcube/rcube_db.php
index a82d344c8..7e5d9fc07 100644
--- a/program/lib/Roundcube/rcube_db.php
+++ b/program/lib/Roundcube/rcube_db.php
@@ -1,1523 +1,1513 @@
 <?php
 
 /**
  +-----------------------------------------------------------------------+
  | This file is part of the Roundcube Webmail client                     |
  |                                                                       |
  | Copyright (C) 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   Framework
  * @subpackage Database
  */
 class rcube_db
 {
     /** @var string Database implementation (mysql, postgres, etc.) */
     public $db_provider;
 
     protected $db_dsnw;               // DSN for write operations
     protected $db_dsnr;               // DSN for read operations
     protected $db_dsnw_array;         // DSN for write operations
     protected $db_dsnr_array;         // DSN for read operations
     protected $db_connected = false;  // Already connected ?
     protected $db_mode;               // Connection mode
     protected $db_pconn = false;      // Persistent connections flag
     protected $dbh;                   // Connection handle
     protected $dbhs = [];
     protected $table_connections = [];
 
     protected $db_error     = false;
     protected $db_error_msg = '';
     protected $conn_failure = false;
     protected $db_index     = 0;
     protected $last_result;
     protected $tables;
     protected $variables;
 
     protected $options = [
         // column/table quotes
         'identifier_start' => '"',
         'identifier_end'   => '"',
         // date/time input format
         'datetime_format'  => 'Y-m-d H:i:s',
         'table_prefix'     => '',
     ];
 
     const DEBUG_LINE_LENGTH = 4096;
     const DEFAULT_QUOTE     = '`';
 
     const TYPE_SQL    = 'sql';
     const TYPE_INT    = 'integer';
     const TYPE_BOOL   = 'bool';
     const TYPE_STRING = 'string';
 
 
     /**
      * 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 = [
             'sqlite2' => 'sqlite',
             'sybase'  => 'mssql',
             'dblib'   => 'mssql',
             'mysqli'  => 'mysql',
             'oci'     => 'oracle',
             'oci8'    => 'oracle',
         ];
 
         $driver = isset($driver_map[$driver]) ? $driver_map[$driver] : $driver;
         $class  = "rcube_db_$driver";
 
         if (!$driver || !class_exists($class)) {
             rcube::raise_error([
                     '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);
 
         $config = rcube::get_instance()->config;
 
         $this->options['table_prefix']  = $config->get('db_prefix');
         $this->options['dsnw_noread']   = $config->get('db_dsnw_noread', false);
         $this->options['table_dsn_map'] = array_map([$this, 'table_name'], $config->get('db_table_dsn', []));
     }
 
     /**
      * Connect to specific database
      *
      * @param array  $dsn  DSN for DB connections
      * @param string $mode Connection mode (r|w)
      */
     protected function dsn_connect($dsn, $mode)
     {
         $this->db_error     = false;
         $this->db_error_msg = null;
 
         // return existing handle
         if (!empty($this->dbhs[$mode])) {
             $this->dbh     = $this->dbhs[$mode];
             $this->db_mode = $mode;
 
             return $this->dbh;
         }
 
         // connect to database
         if ($dbh = $this->conn_create($dsn)) {
             $this->dbhs[$mode]  = $dbh;
             $this->db_mode      = $mode;
             $this->db_connected = true;
         }
     }
 
     /**
      * Create PDO connection
      */
     protected function conn_create($dsn)
     {
         // Get database specific connection options
         $dsn_string  = $this->dsn_string($dsn);
         $dsn_options = $this->dsn_options($dsn);
 
         // 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);
 
             $username = isset($dsn['username']) ? $dsn['username'] : null;
             $password = isset($dsn['password']) ? $dsn['password'] : null;
 
             $this->dbh = new PDO($dsn_string, $username, $password, $dsn_options);
 
             // don't throw exceptions or warnings
             $this->dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
 
             $this->conn_configure($dsn, $this->dbh);
         }
         catch (Exception $e) {
             $this->db_error     = true;
             $this->db_error_msg = $e->getMessage();
 
             rcube::raise_error([
                     'code' => 500, 'type' => 'db',
                     'line' => __LINE__, 'file' => __FILE__,
                     'message' => $this->db_error_msg
                 ],
                 true, false
             );
 
             return null;
         }
 
         return $this->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)
     {
     }
 
     /**
      * Connect to appropriate database depending on the operation
      *
      * @param string $mode  Connection mode (r|w)
      * @param bool   $force Enforce using the given mode
      */
     public function db_connect($mode, $force = false)
     {
         // previous connection failed, don't attempt to connect again
         if ($this->conn_failure) {
             return;
         }
 
         // no replication
         if ($this->db_dsnw == $this->db_dsnr) {
             $mode = 'w';
         }
 
         // Already connected
         if ($this->db_connected) {
             // connected to db with the same or "higher" mode (if allowed)
             if ($this->db_mode == $mode || $this->db_mode == 'w' && !$force && empty($this->options['dsnw_noread'])) {
                 return;
             }
         }
 
         $dsn = ($mode == 'r') ? $this->db_dsnr_array : $this->db_dsnw_array;
         $this->dsn_connect($dsn, $mode);
 
         // use write-master when read-only fails
         if (!$this->db_connected && $mode == 'r' && $this->is_replicated()) {
             $this->dsn_connect($this->db_dsnw_array, 'w');
         }
 
         $this->conn_failure = !$this->db_connected;
     }
 
     /**
      * Analyze the given SQL statement and select the appropriate connection to use
      */
     protected function dsn_select($query)
     {
         // no replication
         if ($this->db_dsnw == $this->db_dsnr) {
             return 'w';
         }
 
         // Read or write ?
         $mode = preg_match('/^(select|show|set)/i', $query) ? 'r' : 'w';
 
         $start = '[' . $this->options['identifier_start'] . self::DEFAULT_QUOTE . ']';
         $end   = '[' . $this->options['identifier_end']   . self::DEFAULT_QUOTE . ']';
         $regex = '/(?:^|\s)(from|update|into|join)\s+'.$start.'?([a-z0-9._]+)'.$end.'?\s+/i';
 
         // find tables involved in this query
         if (preg_match_all($regex, $query, $matches, PREG_SET_ORDER)) {
             foreach ($matches as $m) {
                 $table = $m[2];
 
                 // always use direct mapping
                 if (!empty($this->options['table_dsn_map'][$table])) {
                     $mode = $this->options['table_dsn_map'][$table];
                     break;  // primary table rules
                 }
                 else if ($mode == 'r') {
                     // connected to db with the same or "higher" mode for this table
                     if (isset($this->table_connections[$table])) {
                         $db_mode = $this->table_connections[$table];
                         if ($db_mode == 'w' && empty($this->options['dsnw_noread'])) {
                             $mode = $db_mode;
                         }
                     }
                 }
             }
 
             // remember mode chosen (for primary table)
             $table = $matches[0][2];
             $this->table_connections[$table] = $mode;
         }
 
         return $mode;
     }
 
     /**
      * Activate/deactivate debug mode
      *
      * @param bool $dbg True if SQL queries should be logged
      */
     public function set_debug($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 (!empty($this->options['debug_mode'])) {
             if (($len = strlen($query)) > self::DEBUG_LINE_LENGTH) {
                 $diff  = $len - self::DEBUG_LINE_LENGTH;
                 $query = substr($query, 0, self::DEBUG_LINE_LENGTH)
                     . "... [truncated $diff bytes]";
             }
 
             rcube::write_log('sql', '[' . (++$this->db_index) . '] ' . $query . ';');
         }
     }
 
     /**
      * Getter for an information about the last error.
      *
      * @return ?array [SQLSTATE error code, driver specific error code, driver specific error message]
      */
     public function error_info()
     {
         return $this->dbh ? $this->dbh->errorInfo() : null;
     }
 
     /**
      * Getter for error state
      *
      * @param mixed $result Optional query result
      *
      * @return string Error message
      */
     public function is_error($result = null)
     {
         if ($result !== null) {
             return $result === false ? $this->db_error_msg : null;
         }
 
         return $this->db_error ? $this->db_error_msg : null;
     }
 
-    /**
-     * Getter for error code
-     *
-     * @return array [SQLSTATE error code, driver specific error code, driver specific error message]
-     */
-    public function error_info()
-    {
-        return $this->dbh->errorInfo();
-    }
-
     /**
      * Connection state checker
      *
      * @return bool True if in connected state
      */
     public function is_connected()
     {
         return !is_object($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 rcube::get_instance()->config->get('db_' . $varname, $default);
     }
 
     /**
      * Execute a SQL query
      *
      * @param string SQL query to execute
      * @param mixed  Values to be inserted in query
      *
      * @return PDOStatement|false  Query handle or False on error
      */
     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 PDOStatement|false Query handle or False on error
      */
     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  $params  Values to be inserted in query
      *
      * @return PDOStatement|false Query handle or False on error
      */
     protected function _query($query, $offset, $numrows, $params)
     {
         $query = ltrim($query);
 
         $this->db_connect($this->dsn_select($query), true);
 
         // check connection before proceeding
         if (!$this->is_connected()) {
             return $this->last_result = false;
         }
 
         if ($numrows || $offset) {
             $query = $this->set_limit($query, $numrows, $offset);
         }
 
         // replace self::DEFAULT_QUOTE with driver-specific quoting
         $query = $this->query_parse($query);
 
         // Because in Roundcube we mostly use queries that are
         // executed only once, we will not use prepared queries
         $pos = 0;
         $idx = 0;
 
         if (count($params)) {
             while ($pos = strpos($query, '?', $pos)) {
                 if (isset($query[$pos+1]) && $query[$pos+1] == '?') {  // skip escaped '?'
                     $pos += 2;
                 }
                 else {
                     $val = $this->quote($params[$idx++]);
                     unset($params[$idx-1]);
                     $query = substr_replace($query, $val, $pos, 1);
                     $pos += strlen($val);
                 }
             }
         }
 
         $query = rtrim($query, " \t\n\r\0\x0B;");
 
         // replace escaped '?' and quotes back to normal, see self::quote()
         $query = str_replace(
             ['??', self::DEFAULT_QUOTE.self::DEFAULT_QUOTE],
             ['?', self::DEFAULT_QUOTE],
             $query
         );
 
         // log query
         $this->debug($query);
 
         return $this->query_execute($query);
     }
 
     /**
      * Query execution
      */
     protected function query_execute($query)
     {
         // destroy reference to previous result, required for SQLite driver (#1488874)
         $this->last_result  = null;
         $this->db_error_msg = null;
 
         // send query
         $result = $this->dbh->query($query);
 
         if ($result === false) {
             $result = $this->handle_error($query);
         }
 
         return $this->last_result = $result;
     }
 
     /**
      * Parse SQL query and replace identifier quoting
      *
      * @param string $query SQL query
      *
      * @return string SQL query
      */
     protected function query_parse($query)
     {
         $start = $this->options['identifier_start'];
         $end   = $this->options['identifier_end'];
         $quote = self::DEFAULT_QUOTE;
 
         if ($start == $quote) {
             return $query;
         }
 
         $pos = 0;
         $in  = false;
 
         while ($pos = strpos($query, $quote, $pos)) {
             if (isset($query[$pos+1]) && $query[$pos+1] == $quote) {  // skip escaped quote
                 $pos += 2;
             }
             else {
                 if ($in) {
                     $q  = $end;
                     $in = false;
                 }
                 else {
                     $q  = $start;
                     $in = true;
                 }
 
                 $query = substr_replace($query, $q, $pos, 1);
                 $pos++;
             }
         }
 
         return $query;
     }
 
     /**
      * Helper method to handle DB errors.
      * This by default logs the error but could be overridden by a driver implementation
      *
      * @param string $query Query that triggered the error
      *
      * @return mixed Result to be stored and returned
      */
     protected function handle_error($query)
     {
         $error = $this->dbh->errorInfo();
 
         if (empty($this->options['ignore_key_errors']) || !in_array($error[0], ['23000', '23505'])) {
             $this->db_error = true;
             $this->db_error_msg = sprintf('[%s] %s', $error[1], $error[2]);
 
             if (empty($this->options['ignore_errors'])) {
                 rcube::raise_error([
                         'code' => 500, 'type' => 'db', 'line' => __LINE__, 'file' => __FILE__,
                         'message' => $this->db_error_msg . " (SQL Query: $query)"
                     ], true, false);
             }
         }
 
         return false;
     }
 
     /**
      * INSERT ... ON DUPLICATE KEY UPDATE (or equivalent).
      * When not supported by the engine we do UPDATE and INSERT.
      *
      * @param string $table   Table name (should be already passed via table_name() with quoting)
      * @param array  $keys    Hash array (column => value) of the unique constraint
      * @param array  $columns List of columns to update
      * @param array  $values  List of values to update (number of elements
      *                        should be the same as in $columns)
      *
      * @return PDOStatement|bool Query handle or False on error
      * @todo Multi-insert support
      */
     public function insert_or_update($table, $keys, $columns, $values)
     {
         $columns = array_map(function($i) { return "`$i`"; }, $columns);
         $sets    = array_map(function($i) { return "$i = ?"; }, $columns);
         $where   = $keys;
 
         array_walk($where, function(&$val, $key) {
             $val = $this->quote_identifier($key) . " = " . $this->quote($val);
         });
 
         // First try UPDATE
         $result = $this->query("UPDATE $table SET " . implode(", ", $sets)
             . " WHERE " . implode(" AND ", $where), $values);
 
         // if UPDATE fails use INSERT
         if ($result && !$this->affected_rows($result)) {
             $cols  = implode(', ', array_map(function($i) { return "`$i`"; }, array_keys($keys)));
             $cols .= ', ' . implode(', ', $columns);
             $vals  = implode(', ', array_map(function($i) { return $this->quote($i); }, $keys));
             $vals .= ', ' . rtrim(str_repeat('?, ', count($columns)), ', ');
 
             $result = $this->query("INSERT INTO $table ($cols) VALUES ($vals)", $values);
         }
 
         return $result;
     }
 
     /**
      * Get number of affected rows for the last query
      *
      * @param mixed $result Optional query handle
      *
      * @return int Number of (matching) rows
      */
     public function affected_rows($result = null)
     {
         if ($result || ($result === null && ($result = $this->last_result))) {
             if ($result !== true) {
                 return $result->rowCount();
             }
         }
 
         return 0;
     }
 
     /**
      * Get number of rows for a SQL query
      * If no query handle is specified, the last query will be taken as reference
      *
      * @param mixed $result Optional query handle
      *
      * @return mixed Number of rows or false on failure
      * @deprecated This method shows very poor performance and should be avoided.
      */
     public function num_rows($result = null)
     {
         if (($result || ($result === null && ($result = $this->last_result))) && $result !== true) {
             // repeat query with SELECT COUNT(*) ...
             if (preg_match('/^SELECT\s+(?:ALL\s+|DISTINCT\s+)?(?:.*?)\s+FROM\s+(.*)$/ims', $result->queryString, $m)) {
                 $query = $this->dbh->query('SELECT COUNT(*) FROM ' . $m[1], PDO::FETCH_NUM);
                 return $query ? intval($query->fetchColumn(0)) : false;
             }
             else {
                 $num = count($result->fetchAll());
                 $result->execute();  // re-execute query because there's no seek(0)
                 return $num;
             }
         }
 
         return false;
     }
 
     /**
      * 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);
         }
 
         return $this->dbh->lastInsertId($table);
     }
 
     /**
      * Get an associative array for one row
      * If no query handle is specified, the last query will be taken as reference
      *
      * @param mixed $result Optional query handle
      *
      * @return array|false Array with col values or false on failure
      */
     public function fetch_assoc($result = null)
     {
         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 mixed $result Optional query handle
      *
      * @return array|false Array with col values or false on failure
      */
     public function fetch_array($result = null)
     {
         return $this->_fetch_row($result, PDO::FETCH_NUM);
     }
 
     /**
      * Get col values for a result row
      *
      * @param mixed $result Optional query handle
      * @param int   $mode   Fetch mode identifier
      *
      * @return array|false Array with col values or false on failure
      */
     protected function _fetch_row($result, $mode)
     {
         if ($result || ($result === null && ($result = $this->last_result))) {
             if ($result !== true) {
                 return $result->fetch($mode);
             }
         }
 
         return false;
     }
 
     /**
      * 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"
                 . " WHERE TABLE_TYPE = 'BASE TABLE'"
                 . " ORDER BY TABLE_NAME"
             );
 
             $this->tables = $q ? $q->fetchAll(PDO::FETCH_COLUMN, 0) : [];
         }
 
         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 = ?', $table);
 
         if ($q) {
             return $q->fetchAll(PDO::FETCH_COLUMN, 0);
         }
 
         return [];
     }
 
     /**
      * Start transaction
      *
      * @return bool True on success, False on failure
      */
     public function startTransaction()
     {
         $this->db_connect('w', true);
 
         // check connection before proceeding
         if (!$this->is_connected()) {
             return $this->last_result = false;
         }
 
         $this->debug('BEGIN TRANSACTION');
 
         return $this->last_result = $this->dbh->beginTransaction();
     }
 
     /**
      * Commit transaction
      *
      * @return bool True on success, False on failure
      */
     public function endTransaction()
     {
         $this->db_connect('w', true);
 
         // check connection before proceeding
         if (!$this->is_connected()) {
             return $this->last_result = false;
         }
 
         $this->debug('COMMIT TRANSACTION');
 
         return $this->last_result = $this->dbh->commit();
     }
 
     /**
      * Rollback transaction
      *
      * @return bool True on success, False on failure
      */
     public function rollbackTransaction()
     {
         $this->db_connect('w', true);
 
         // check connection before proceeding
         if (!$this->is_connected()) {
             return $this->last_result = false;
         }
 
         $this->debug('ROLLBACK TRANSACTION');
 
         return $this->last_result = $this->dbh->rollBack();
     }
 
     /**
      * Release resources related to the last query result.
      * When we know we don't need to access the last query result we can destroy it
      * and release memory. Useful especially if the query returned big chunk of data.
      */
     public function reset()
     {
         $this->last_result = null;
     }
 
     /**
      * Terminate database connection.
      */
     public function closeConnection()
     {
         $this->db_connected = false;
         $this->db_index     = 0;
 
         // release statement and connection resources
         $this->last_result  = null;
         $this->dbh          = null;
         $this->dbhs         = [];
     }
 
     /**
      * Formats input so it can be safely used in a query
      *
      * @param mixed  $input Value to quote
      * @param string $type  Type of data (integer, bool, ident)
      *
      * @return string Quoted/converted string for use in query
      */
     public function quote($input, $type = null)
     {
         if ($input instanceof rcube_db_param) {
             return (string) $input;
         }
 
         // handle int directly for better performance
         if ($type == 'integer' || $type == 'int') {
             return intval($input);
         }
 
         if (is_null($input)) {
             return 'NULL';
         }
 
         if ($input instanceof DateTime) {
             return $this->quote($input->format($this->options['datetime_format']));
         }
 
         if ($type == 'ident') {
             return $this->quote_identifier($input);
         }
 
         // create DB handle if not available
         if (!$this->dbh) {
             $this->db_connect('r');
         }
 
         if ($this->dbh) {
             $map = [
                 'bool'    => PDO::PARAM_BOOL,
                 'integer' => PDO::PARAM_INT,
             ];
 
             $type = isset($map[$type]) ? $map[$type] : PDO::PARAM_STR;
 
             return strtr($this->dbh->quote($input, $type),
                 // escape ? and `
                 ['?' => '??', self::DEFAULT_QUOTE => self::DEFAULT_QUOTE.self::DEFAULT_QUOTE]
             );
         }
 
         return 'NULL';
     }
 
     /**
      * Escapes a string so it can be safely used in a query
      *
      * @param string $str A string to escape
      *
      * @return string Escaped string for use in a query
      */
     public function escape($str)
     {
         if (is_null($str)) {
             return 'NULL';
         }
 
         return substr($this->quote($str), 1, -1);
     }
 
     /**
      * 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);
     }
 
     /**
      * Escapes a string so it can be safely used in a query
      *
      * @param string $str A string to escape
      *
      * @return string Escaped string for use in a query
      * @deprecated    Replaced by rcube_db::escape
      * @see           rcube_db::escape
      */
     public function escapeSimple($str)
     {
         return $this->escape($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  = [];
 
         foreach (explode('.', $str) as $elem) {
             $elem = str_replace([$start, $end], '', $elem);
             $name[] = $start . $elem . $end;
         }
 
         return implode('.', $name);
     }
 
     /**
      * Create query parameter object
      *
      * @param mixed  $value Parameter value
      * @param string $type  Parameter type (one of rcube_db::TYPE_* constants)
      */
     public function param($value, $type = null)
     {
         return new rcube_db_param($this, $value, $type);
     }
 
     /**
      * Return SQL function for current time and date
      *
      * @param int $interval Optional interval (in seconds) to add/subtract
      *
      * @return string SQL function to use in query
      */
     public function now($interval = 0)
     {
         $result = 'now()';
 
         if ($interval) {
             $result .= ' ' . ($interval > 0 ? '+' : '-') . ' INTERVAL '
                 . ($interval > 0 ? intval($interval) : intval($interval) * -1)
                 . ' SECOND';
         }
 
         return $result;
     }
 
     /**
      * Return list of elements for use with SQL's IN clause
      *
      * @param array  $arr  Input array
      * @param string $type Type of data (integer, bool, ident)
      *
      * @return string Comma-separated list of quoted values for use in query
      */
     public function array2list($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 $timestamp Unix timestamp
      *
      * @return string Date string in db-specific format
      * @deprecated
      */
     public function fromunixtime($timestamp)
     {
         return $this->quote(date($this->options['datetime_format'], $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, ... */)
     {
         $args = func_get_args();
         if (!empty($args) && is_array($args[0])) {
             $args = $args[0];
         }
 
         return '(' . implode(' || ', $args) . ')';
     }
 
     /**
      * Encodes non-UTF-8 characters in string/array/object (recursive)
      *
      * @param mixed $input      Data to fix
      * @param bool  $serialized Enable serialization
      *
      * @return mixed Properly UTF-8 encoded data
      */
     public static function encode($input, $serialized = false)
     {
         // use Base64 encoding to workaround issues with invalid
         // or null characters in serialized string (#1489142)
         if ($serialized) {
             return base64_encode(serialize($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
      * @param bool  $serialized Enable serialization
      *
      * @return mixed Decoded data
      */
     public static function decode($input, $serialized = false)
     {
         // use Base64 encoding to workaround issues with invalid
         // or null characters in serialized string (#1489142)
         if ($serialized) {
             // Keep backward compatibility where base64 wasn't used
             if (strpos(substr($input, 0, 16), ':') !== false) {
                 return self::decode(@unserialize($input));
             }
 
             return @unserialize(base64_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);
     }
 
     /**
      * Return correct name for a specific database table
      *
      * @param string $table  Table name
      * @param bool   $quoted Quote table identifier
      *
      * @return string Translated table name
      */
     public function table_name($table, $quoted = false)
     {
         // let plugins alter the table name (#1489837)
         $plugin = rcube::get_instance()->plugins->exec_hook('db_table_name', ['table' => $table]);
         $table = $plugin['table'];
 
         // add prefix to the table name if configured
         if (($prefix = $this->options['table_prefix']) && strpos($table, $prefix) !== 0) {
             $table = $prefix . $table;
         }
 
         if ($quoted) {
             $table = $this->quote_identifier($table);
         }
 
         return $table;
     }
 
     /**
      * Set class option value
      *
      * @param string $name  Option name
      * @param mixed  $value Option value
      */
     public function set_option($name, $value)
     {
         $this->options[$name] = $value;
     }
 
     /**
      * Set DSN connection to be used for the given table
      *
      * @param string $table Table name
      * @param string $mode  DSN connection ('r' or 'w') to be used
      */
     public function set_table_dsn($table, $mode)
     {
         $this->options['table_dsn_map'][$this->table_name($table)] = $mode;
     }
 
     /**
      * MDB2 DSN string parser
      *
      * @param string $sequence Sequence name
      *
      * @return array DSN parameters
      */
     public static function parse_dsn($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' && strlen($proto_opts)) {
             $parsed['hostspec'] = $proto_opts;
         }
         else if ($parsed['protocol'] == 'unix') {
             $parsed['socket'] = $proto_opts;
         }
 
         // Get database if any
         // $dsn => database
         if ($dsn) {
             // /database
             if (($pos = strpos($dsn, '?')) === false) {
                 $parsed['database'] = rawurldecode($dsn);
             }
             else {
                 // /database?param1=value1&param2=value2
                 $parsed['database'] = rawurldecode(substr($dsn, 0, $pos));
                 $dsn = substr($dsn, $pos + 1);
 
                 if (strpos($dsn, '&') !== false) {
                     $opts = explode('&', $dsn);
                 }
                 else { // database?param1=value1
                     $opts = [$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);
                     }
                 }
             }
 
             // remove problematic suffix (#7034)
             $parsed['database'] = preg_replace('/;.*$/', '', $parsed['database']);
 
             // Resolve relative path to the sqlite database file
             // so for example it works with Roundcube Installer
             if (!empty($parsed['phptype']) && !empty($parsed['database'])
                 && stripos($parsed['phptype'], 'sqlite') === 0
                 && $parsed['database'][0] != '/'
                 && strpos($parsed['database'], ':') === false
             ) {
                 $parsed['database'] = INSTALL_PATH . $parsed['database'];
             }
         }
 
         return $parsed;
     }
 
     /**
      * Returns PDO DSN string from DSN array
      *
      * @param array $dsn DSN parameters
      *
      * @return string DSN string
      */
     protected function dsn_string($dsn)
     {
         $params = [];
         $result = $dsn['phptype'] . ':';
 
         if (isset($dsn['hostspec'])) {
             $params[] = 'host=' . $dsn['hostspec'];
         }
 
         if (isset($dsn['port'])) {
             $params[] = 'port=' . $dsn['port'];
         }
 
         if (isset($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 = [];
 
         if ($this->db_pconn) {
             $result[PDO::ATTR_PERSISTENT] = true;
         }
 
         if (!empty($dsn['prefetch'])) {
             $result[PDO::ATTR_PREFETCH] = (int) $dsn['prefetch'];
         }
 
         if (!empty($dsn['timeout'])) {
             $result[PDO::ATTR_TIMEOUT] = (int) $dsn['timeout'];
         }
 
         return $result;
     }
 
     /**
      * Execute the given SQL script
      *
      * @param string $sql SQL queries to execute
      *
      * @return boolean True on success, False on error
      */
     public function exec_script($sql)
     {
         $sql  = $this->fix_table_names($sql);
         $buff = '';
         $exec = '';
 
         foreach (explode("\n", $sql) as $line) {
             $trimmed = trim($line);
             if ($trimmed == '' || preg_match('/^--/', $trimmed)) {
                 continue;
             }
 
             if ($trimmed == 'GO') {
                 $exec = $buff;
             }
             else if ($trimmed[strlen($trimmed)-1] == ';') {
                 $exec = $buff . substr(rtrim($line), 0, -1);
             }
 
             if ($exec) {
                 $this->query($exec);
                 $buff = '';
                 $exec = '';
                 if ($this->db_error) {
                     break;
                 }
             }
             else {
                 $buff .= $line . "\n";
             }
         }
 
         return !$this->db_error;
     }
 
     /**
      * Parse SQL file and fix table names according to table prefix
      */
     protected function fix_table_names($sql)
     {
         if (!$this->options['table_prefix']) {
             return $sql;
         }
 
         $sql = preg_replace_callback(
             '/((TABLE|TRUNCATE( TABLE)?|(?<!ON )UPDATE|INSERT INTO|FROM'
             . '| ON(?! (DELETE|UPDATE))|REFERENCES|CONSTRAINT|FOREIGN KEY|INDEX|UNIQUE( INDEX)?)'
             . '\s+(IF (NOT )?EXISTS )?[`"]*)([^`"\( \r\n]+)/',
             [$this, 'fix_table_names_callback'],
             $sql
         );
 
         return $sql;
     }
 
     /**
      * Preg_replace callback for fix_table_names()
      */
     protected function fix_table_names_callback($matches)
     {
         $prefix = $this->options['table_prefix'];
 
         // Schema prefix (ends with a dot)
         if ($prefix[strlen($prefix)-1] === '.') {
             // These can't have a schema prefix
             if (preg_match('/(CONSTRAINT|UNIQUE|INDEX)[\s\t`"]*$/', $matches[1])) {
                 $prefix = '';
             }
             else {
                 // check if the identifier is quoted, then quote the prefix
                 $last = $matches[1][strlen($matches[1])-1];
 
                 if ($last === '`' || $last === '"') {
                     $prefix = substr($prefix, 0, -1) . $last . '.' . $last;
                 }
             }
         }
 
         return $matches[1] . $prefix . $matches[count($matches)-1];
     }
 }