New database layer based on PHP PDO

11 files changed, 1609 insertions, 14 deletions

diff --git a/program/include/rcube.php b/program/include/rcube.php
index 1bfe93d6c..3e43ace96 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;
 
@@ -158,15 +158,13 @@ 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 01f620381..73c5eacea 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..6984b49cc 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;
@@ -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..64db6d5d0
--- /dev/null
+++ b/program/include/rcube_db.php
@@ -0,0 +1,976 @@
+<?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 $tables;
+    protected $db_index = 0;
+
+    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',
+        );
+
+        $driver = isset($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();
+    }
+
+
+    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 {
+            $this->conn_prepare($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 (PDOException $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 $dbh;
+    }
+
+
+    protected function conn_prepare($dsn)
+    {
+    }
+
+    protected function conn_configure($dsn, $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_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'] = $dbg;
+    }
+
+
+    protected function set_charset($charset)
+    {
+        $this->query("SET NAMES 'utf8'");
+    }
+
+
+    /**
+     * Getter for error state
+     *
+     * @param  boolean  True on error
+     */
+    public function is_error()
+    {
+        return $this->db_error ? $this->db_error_msg : false;
+    }
+
+
+    /**
+     * Connection state checker
+     *
+     * @param  boolean  True if in connected state
+     */
+    public function is_connected()
+    {
+        return !is_object($this->dbh) ? 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;
+    }
+
+
+    /**
+     * 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  $params  Values to be inserted in query
+     * @return number  Query handle identifier
+     */
+    protected function _query($query, $offset, $numrows, $params)
+    {
+        // Read or write ?
+        $mode = preg_match('/^select/i', ltrim($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, ';');
+
+        if ($this->options['debug_mode']) {
+            rcube::write_log('sql', '[' . (++$this->db_index) . '] ' . $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 $res_id Optional query handle identifier
+     * @return mixed   Number of rows or false on failure
+     */
+    public function affected_rows($res_id = null)
+    {
+        if ($result = $this->_get_result($res_id)) {
+            return $result->rowCount();
+        }
+
+        return 0;
+    }
+
+
+    /**
+     * Get last inserted record ID
+     * 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) {
+            // 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  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, 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  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, PDO::FETCH_NUM);
+    }
+
+
+    /**
+     * Get col values for a result row
+     *
+     * @param  PDOStatement $result Result handle
+     * @param  number       $mode   Fetch mode identifier
+     *
+     * @return mixed  Array with col values or false on failure
+     */
+    protected function _fetch_row($result, $mode)
+    {
+        if (!is_object($result) || !$this->is_connected()) {
+            return false;
+        }
+
+        return $result->fetch($mode);
+    }
+
+
+    /**
+     * Adds LIMIT,OFFSET clauses to the query
+     *
+     */
+    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 $this->tables;
+    }
+
+
+    /**
+     * Returns list of columns in database table
+     *
+     * @param string Table name
+     *
+     * @return array List of table cols
+     */
+    public function list_cols($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  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)
+    {
+        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 $res Query handle
+     *
+     * @return mixed   Handle ID
+     */
+    protected function _add_result($res)
+    {
+        $res_id = sizeof($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 $res_id Handle ID
+     *
+     * @return mixed   Resource handle or false on failure
+     */
+    protected function _get_result($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;
+    }
+
+
+    /**
+     * 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 $sequence;
+    }
+
+
+    /**
+     * MDB2 DSN string parser
+     */
+    public static function parse_dsn($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, $pos);
+            } elseif (strpos($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 $parsed;
+    }
+
+    /**
+     * Returns PDO DSN string from DSN array (parse_dsn() result)
+     */
+    protected function dsn_string($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 $result;
+    }
+
+    /**
+     * Returns PDO driver options array from DSN array (parse_dsn() result)
+     */
+    protected function dsn_options($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..1f7328c3e
--- /dev/null
+++ b/program/include/rcube_db_mssql.php
@@ -0,0 +1,135 @@
+<?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
+{
+    protected function init()
+    {
+        $this->options['identifier_start'] = '[';
+        $this->options['identifier_end'] = ']';
+    }
+
+    protected function set_charset($charset)
+    {
+    }
+
+
+    /**
+     * 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('+', $args) . ')';
+    }
+
+
+    /**
+     * Adds TOP (LIMIT,OFFSET) clause to the query
+     *
+     */
+    protected function set_limit($query, $limit = 0, $offset = 0)
+    {
+        // code from MDB2 package
+        if ($limit > 0) {
+            $fetch = $offset + $limit;
+            return preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',
+                "\\1SELECT\\2 TOP $fetch", $query);
+        }
+
+// @TODO: proper OFFSET handling i _fetch_row()
+
+        return $query;
+    }
+
+
+    /**
+     * Returns PDO DSN string from DSN array (parse_dsn() result)
+     */
+    protected function dsn_string($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..3eeee2ada
--- /dev/null
+++ b/program/include/rcube_db_mysql.php
@@ -0,0 +1,92 @@
+<?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
+{
+    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(', ', $args) . ')';
+    }
+
+
+    /**
+     * Returns PDO DSN string from DSN array (parse_dsn() result)
+     */
+    protected function dsn_string($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;
+    }
+
+}
diff --git a/program/include/rcube_db_pgsql.php b/program/include/rcube_db_pgsql.php
new file mode 100644
index 000000000..63bd92b40
--- /dev/null
+++ b/program/include/rcube_db_pgsql.php
@@ -0,0 +1,89 @@
+<?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
+     * For Postgres databases, a table 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) {
+            $table = $this->sequence_name($table);
+        }
+
+        $id = $this->dbh->lastInsertId($table);
+
+        return $id;
+    }
+
+
+    /**
+     * 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);
+    }
+
+}
diff --git a/program/include/rcube_db_sqlite.php b/program/include/rcube_db_sqlite.php
new file mode 100644
index 000000000..fe6b0dca9
--- /dev/null
+++ b/program/include/rcube_db_sqlite.php
@@ -0,0 +1,169 @@
+<?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
+{
+
+    protected function set_charset($charset)
+    {
+    }
+
+    protected function conn_prepare($dsn)
+    {
+        // Create database file, required by PDO to exist on connection
+        if (!empty($dsn['database']) && !file_exists($dsn['database'])) {
+            touch($dsn['database']);
+        }
+    }
+
+    protected function conn_configure($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)) {
+                if ($this->options['debug_mode']) {
+                    $this::debug('INITIALIZE DATABASE');
+                }
+
+                $q = $dbh->exec($data);
+
+                if ($q === 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' => $this->db_error_msg), true, false);
+                }
+            }
+        }
+    }
+
+
+    /**
+     * Callback for sqlite: unix_timestamp()
+     */
+    public static function sqlite_unix_timestamp($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 $this->tables;
+    }
+
+
+    /**
+     * Returns list of columns in database table
+     *
+     * @param string Table name
+     *
+     * @return array List of table cols
+     */
+    public function list_cols($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 $columns;
+    }
+
+
+    protected function dsn_string($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..af97a819f
--- /dev/null
+++ b/program/include/rcube_db_sqlsrv.php
@@ -0,0 +1,135 @@
+<?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
+{
+    protected function init()
+    {
+        $this->options['identifier_start'] = '[';
+        $this->options['identifier_end'] = ']';
+    }
+
+    protected function set_charset($charset)
+    {
+    }
+
+
+    /**
+     * 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('+', $args) . ')';
+    }
+
+
+    /**
+     * Adds TOP (LIMIT,OFFSET) clause to the query
+     *
+     */
+    protected function set_limit($query, $limit = 0, $offset = 0)
+    {
+        // code from MDB2 package
+        if ($limit > 0) {
+            $fetch = $offset + $limit;
+            return preg_replace('/^([\s(])*SELECT( DISTINCT)?(?!\s*TOP\s*\()/i',
+                "\\1SELECT\\2 TOP $fetch", $query);
+        }
+
+// @TODO: proper OFFSET handling i _fetch_row()
+
+        return $query;
+    }
+
+    /**
+     * Returns PDO DSN string from DSN array (parse_dsn() result)
+     */
+    protected function dsn_string($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 eb2df165f..f6f53127d 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_user.php b/program/include/rcube_user.php
index 76f74da7c..1a54b91a2 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;