Merge CodeIgniter 3 support

1 files changed, 283 insertions, 515 deletions

diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index a0896d8aa..b59e89494 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -1,413 +1,327 @@
-<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
- * An open source application development framework for PHP 5.1.6 or newer
+ * An open source application development framework for PHP
  *
- * @package		CodeIgniter
- * @author		ExpressionEngine Dev Team
- * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc.
- * @license		http://codeigniter.com/user_guide/license.html
- * @link		http://codeigniter.com
- * @since		Version 1.0
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	https://codeigniter.com
+ * @since	Version 1.3.0
  * @filesource
  */
-
-// ------------------------------------------------------------------------
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
- * MySQLi Database Adapter Class - MySQLi only works with PHP 5
+ * MySQLi Database Adapter Class
  *
  * Note: _DB is an extender class that the app controller
- * creates dynamically based on whether the active record
+ * creates dynamically based on whether the query builder
  * class is being used or not.
  *
  * @package		CodeIgniter
  * @subpackage	Drivers
  * @category	Database
- * @author		ExpressionEngine Dev Team
- * @link		http://codeigniter.com/user_guide/database/
+ * @author		EllisLab Dev Team
+ * @link		https://codeigniter.com/user_guide/database/
  */
 class CI_DB_mysqli_driver extends CI_DB {
 
-	var $dbdriver = 'mysqli';
-
-	// The character used for escaping
-	var $_escape_char = '`';
-
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	var $_like_escape_str = '';
-	var $_like_escape_chr = '';
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
+	public $dbdriver = 'mysqli';
 
 	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
+	 * Compression flag
+	 *
+	 * @var	bool
 	 */
-	var $_count_string = "SELECT COUNT(*) AS ";
-	var $_random_keyword = ' RAND()'; // database specific random keyword
+	public $compress = FALSE;
 
 	/**
+	 * DELETE hack flag
+	 *
 	 * Whether to use the MySQL "delete hack" which allows the number
 	 * of affected rows to be shown. Uses a preg_replace when enabled,
 	 * adding a bit more processing to all queries.
-	 */
-	var $delete_hack = TRUE;
-
-	// whether SET NAMES must be used to set the character set
-	var $use_set_names;
-	
-	// --------------------------------------------------------------------
-
-	/**
-	 * Non-persistent database connection
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @var	bool
 	 */
-	function db_connect()
-	{
-		if ($this->port != '')
-		{
-			return @mysqli_connect($this->hostname, $this->username, $this->password, $this->database, $this->port);
-		}
-		else
-		{
-			return @mysqli_connect($this->hostname, $this->username, $this->password, $this->database);
-		}
-
-	}
-
-	// --------------------------------------------------------------------
+	public $delete_hack = TRUE;
 
 	/**
-	 * Persistent database connection
+	 * Strict ON flag
+	 *
+	 * Whether we're running in strict SQL mode.
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @var	bool
 	 */
-	function db_pconnect()
-	{
-		return $this->db_connect();
-	}
+	public $stricton;
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Reconnect
-	 *
-	 * Keep / reestablish the db connection if no queries have been
-	 * sent for a length of time exceeding the server's idle timeout
+	 * Identifier escape character
 	 *
-	 * @access	public
-	 * @return	void
+	 * @var	string
 	 */
-	function reconnect()
-	{
-		if (mysqli_ping($this->conn_id) === FALSE)
-		{
-			$this->conn_id = FALSE;
-		}
-	}
+	protected $_escape_char = '`';
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Select the database
+	 * MySQLi object
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * Has to be preserved without being assigned to $conn_id.
+	 *
+	 * @var	MySQLi
 	 */
-	function db_select()
-	{
-		return @mysqli_select_db($this->conn_id, $this->database);
-	}
+	protected $_mysqli;
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Set client character set
+	 * Database connection
 	 *
-	 * @access	private
-	 * @param	string
-	 * @param	string
-	 * @return	resource
+	 * @param	bool	$persistent
+	 * @return	object
 	 */
-	function _db_set_charset($charset, $collation)
+	public function db_connect($persistent = FALSE)
 	{
-		if ( ! isset($this->use_set_names))
+		// Do we have a socket path?
+		if ($this->hostname[0] === '/')
 		{
-			// mysqli_set_charset() requires MySQL >= 5.0.7, use SET NAMES as fallback
-			$this->use_set_names = (version_compare(mysqli_get_server_info($this->conn_id), '5.0.7', '>=')) ? FALSE : TRUE;
-		}
-
-		if ($this->use_set_names === TRUE)
-		{
-			return @mysqli_query($this->conn_id, "SET NAMES '".$this->escape_str($charset)."' COLLATE '".$this->escape_str($collation)."'");
+			$hostname = NULL;
+			$port = NULL;
+			$socket = $this->hostname;
 		}
 		else
 		{
-			return @mysqli_set_charset($this->conn_id, $charset);
+			$hostname = ($persistent === TRUE)
+				? 'p:'.$this->hostname : $this->hostname;
+			$port = empty($this->port) ? NULL : $this->port;
+			$socket = NULL;
 		}
-	}
 
-	// --------------------------------------------------------------------
+		$client_flags = ($this->compress === TRUE) ? MYSQLI_CLIENT_COMPRESS : 0;
+		$this->_mysqli = mysqli_init();
 
-	/**
-	 * Version number query string
-	 *
-	 * @access	public
-	 * @return	string
-	 */
-	function _version()
-	{
-		return "SELECT version() AS ver";
-	}
+		$this->_mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 10);
 
-	// --------------------------------------------------------------------
+		if (isset($this->stricton))
+		{
+			if ($this->stricton)
+			{
+				$this->_mysqli->options(MYSQLI_INIT_COMMAND, 'SET SESSION sql_mode = CONCAT(@@sql_mode, ",", "STRICT_ALL_TABLES")');
+			}
+			else
+			{
+				$this->_mysqli->options(MYSQLI_INIT_COMMAND,
+					'SET SESSION sql_mode =
+					REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
+					@@sql_mode,
+					"STRICT_ALL_TABLES,", ""),
+					",STRICT_ALL_TABLES", ""),
+					"STRICT_ALL_TABLES", ""),
+					"STRICT_TRANS_TABLES,", ""),
+					",STRICT_TRANS_TABLES", ""),
+					"STRICT_TRANS_TABLES", "")'
+				);
+			}
+		}
 
-	/**
-	 * Execute the query
-	 *
-	 * @access	private called by the base class
-	 * @param	string	an SQL query
-	 * @return	resource
-	 */
-	function _execute($sql)
-	{
-		$sql = $this->_prep_query($sql);
-		$result = @mysqli_query($this->conn_id, $sql);
-		return $result;
-	}
+		if (is_array($this->encrypt))
+		{
+			$ssl = array();
+			empty($this->encrypt['ssl_key'])    OR $ssl['key']    = $this->encrypt['ssl_key'];
+			empty($this->encrypt['ssl_cert'])   OR $ssl['cert']   = $this->encrypt['ssl_cert'];
+			empty($this->encrypt['ssl_ca'])     OR $ssl['ca']     = $this->encrypt['ssl_ca'];
+			empty($this->encrypt['ssl_capath']) OR $ssl['capath'] = $this->encrypt['ssl_capath'];
+			empty($this->encrypt['ssl_cipher']) OR $ssl['cipher'] = $this->encrypt['ssl_cipher'];
+
+			if ( ! empty($ssl))
+			{
+				if (isset($this->encrypt['ssl_verify']))
+				{
+					if ($this->encrypt['ssl_verify'])
+					{
+						defined('MYSQLI_OPT_SSL_VERIFY_SERVER_CERT') && $this->_mysqli->options(MYSQLI_OPT_SSL_VERIFY_SERVER_CERT, TRUE);
+					}
+					// Apparently (when it exists), setting MYSQLI_OPT_SSL_VERIFY_SERVER_CERT
+					// to FALSE didn't do anything, so PHP 5.6.16 introduced yet another
+					// constant ...
+					//
+					// https://secure.php.net/ChangeLog-5.php#5.6.16
+					// https://bugs.php.net/bug.php?id=68344
+					elseif (defined('MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT'))
+					{
+						$client_flags |= MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT;
+					}
+				}
 
-	// --------------------------------------------------------------------
+				$client_flags |= MYSQLI_CLIENT_SSL;
+				$this->_mysqli->ssl_set(
+					isset($ssl['key'])    ? $ssl['key']    : NULL,
+					isset($ssl['cert'])   ? $ssl['cert']   : NULL,
+					isset($ssl['ca'])     ? $ssl['ca']     : NULL,
+					isset($ssl['capath']) ? $ssl['capath'] : NULL,
+					isset($ssl['cipher']) ? $ssl['cipher'] : NULL
+				);
+			}
+		}
 
-	/**
-	 * Prep the query
-	 *
-	 * If needed, each database adapter can prep the query string
-	 *
-	 * @access	private called by execute()
-	 * @param	string	an SQL query
-	 * @return	string
-	 */
-	function _prep_query($sql)
-	{
-		// "DELETE FROM TABLE" returns 0 affected rows This hack modifies
-		// the query so that it returns the number of affected rows
-		if ($this->delete_hack === TRUE)
+		if ($this->_mysqli->real_connect($hostname, $this->username, $this->password, $this->database, $port, $socket, $client_flags))
 		{
-			if (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
+			// Prior to version 5.7.3, MySQL silently downgrades to an unencrypted connection if SSL setup fails
+			if (
+				($client_flags & MYSQLI_CLIENT_SSL)
+				&& version_compare($this->_mysqli->client_info, '5.7.3', '<=')
+				&& empty($this->_mysqli->query("SHOW STATUS LIKE 'ssl_cipher'")->fetch_object()->Value)
+			)
 			{
-				$sql = preg_replace("/^\s*DELETE\s+FROM\s+(\S+)\s*$/", "DELETE FROM \\1 WHERE 1=1", $sql);
+				$this->_mysqli->close();
+				$message = 'MySQLi was configured for an SSL connection, but got an unencrypted connection instead!';
+				log_message('error', $message);
+				return ($this->db_debug) ? $this->display_error($message, '', TRUE) : FALSE;
 			}
+
+			return $this->_mysqli;
 		}
 
-		return $sql;
+		return FALSE;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Begin Transaction
+	 * Reconnect
 	 *
-	 * @access	public
-	 * @return	bool
+	 * Keep / reestablish the db connection if no queries have been
+	 * sent for a length of time exceeding the server's idle timeout
+	 *
+	 * @return	void
 	 */
-	function trans_begin($test_mode = FALSE)
+	public function reconnect()
 	{
-		if ( ! $this->trans_enabled)
+		if ($this->conn_id !== FALSE && $this->conn_id->ping() === FALSE)
 		{
-			return TRUE;
-		}
-
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
-		{
-			return TRUE;
+			$this->conn_id = FALSE;
 		}
-
-		// Reset the transaction failure flag.
-		// If the $test_mode flag is set to TRUE transactions will be rolled back
-		// even if the queries produce a successful result.
-		$this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;
-
-		$this->simple_query('SET AUTOCOMMIT=0');
-		$this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK
-		return TRUE;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Commit Transaction
+	 * Select the database
 	 *
-	 * @access	public
+	 * @param	string	$database
 	 * @return	bool
 	 */
-	function trans_commit()
+	public function db_select($database = '')
 	{
-		if ( ! $this->trans_enabled)
+		if ($database === '')
 		{
-			return TRUE;
+			$database = $this->database;
 		}
 
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ($this->conn_id->select_db($database))
 		{
+			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
-		$this->simple_query('COMMIT');
-		$this->simple_query('SET AUTOCOMMIT=1');
-		return TRUE;
+		return FALSE;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Rollback Transaction
+	 * Set client character set
 	 *
-	 * @access	public
+	 * @param	string	$charset
 	 * @return	bool
 	 */
-	function trans_rollback()
+	protected function _db_set_charset($charset)
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
-		{
-			return TRUE;
-		}
-
-		$this->simple_query('ROLLBACK');
-		$this->simple_query('SET AUTOCOMMIT=1');
-		return TRUE;
+		return $this->conn_id->set_charset($charset);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Escape String
+	 * Database version number
 	 *
-	 * @access	public
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
-	function escape_str($str, $like = FALSE)
+	public function version()
 	{
-		if (is_array($str))
+		if (isset($this->data_cache['version']))
 		{
-			foreach ($str as $key => $val)
-			{
-				$str[$key] = $this->escape_str($val, $like);
-			}
-
-			return $str;
+			return $this->data_cache['version'];
 		}
 
-		if (function_exists('mysqli_real_escape_string') AND is_object($this->conn_id))
-		{
-			$str = mysqli_real_escape_string($this->conn_id, $str);
-		}
-		elseif (function_exists('mysql_escape_string'))
-		{
-			$str = mysql_escape_string($str);
-		}
-		else
-		{
-			$str = addslashes($str);
-		}
-
-		// escape LIKE condition wildcards
-		if ($like === TRUE)
-		{
-			$str = str_replace(array('%', '_'), array('\\%', '\\_'), $str);
-		}
-
-		return $str;
+		return $this->data_cache['version'] = $this->conn_id->server_info;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Affected Rows
-	 *
-	 * @access	public
-	 * @return	integer
-	 */
-	function affected_rows()
-	{
-		return @mysqli_affected_rows($this->conn_id);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Insert ID
+	 * Execute the query
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @param	string	$sql	an SQL query
+	 * @return	mixed
 	 */
-	function insert_id()
+	protected function _execute($sql)
 	{
-		return @mysqli_insert_id($this->conn_id);
+		return $this->conn_id->query($this->_prep_query($sql));
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * "Count All" query
-	 *
-	 * Generates a platform-specific query string that counts all records in
-	 * the specified database
-	 *
-	 * @access	public
-	 * @param	string
-	 * @return	string
-	 */
-	function count_all($table = '')
-	{
-		if ($table == '')
-		{
-			return 0;
-		}
-
-		$query = $this->query($this->_count_string . $this->_protect_identifiers('numrows') . " FROM " . $this->_protect_identifiers($table, TRUE, NULL, FALSE));
-
-		if ($query->num_rows() == 0)
-		{
-			return 0;
-		}
-
-		$row = $query->row();
-		$this->_reset_select();
-		return (int) $row->numrows;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * List table query
+	 * Prep the query
 	 *
-	 * Generates a platform-specific query string so that the table names can be fetched
+	 * If needed, each database adapter can prep the query string
 	 *
-	 * @access	private
-	 * @param	boolean
+	 * @param	string	$sql	an SQL query
 	 * @return	string
 	 */
-	function _list_tables($prefix_limit = FALSE)
+	protected function _prep_query($sql)
 	{
-		$sql = "SHOW TABLES FROM ".$this->_escape_char.$this->database.$this->_escape_char;
-
-		if ($prefix_limit !== FALSE AND $this->dbprefix != '')
+		// mysqli_affected_rows() returns 0 for "DELETE FROM TABLE" queries. This hack
+		// modifies the query so that it a proper number of affected rows is returned.
+		if ($this->delete_hack === TRUE && preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
 		{
-			$sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return trim($sql).' WHERE 1=1';
 		}
 
 		return $sql;
@@ -416,342 +330,203 @@ class CI_DB_mysqli_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Show column query
-	 *
-	 * Generates a platform-specific query string so that the column names can be fetched
+	 * Begin Transaction
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @return	string
+	 * @return	bool
 	 */
-	function _list_columns($table = '')
+	protected function _trans_begin()
 	{
-		return "SHOW COLUMNS FROM ".$this->_protect_identifiers($table, TRUE, NULL, FALSE);
+		$this->conn_id->autocommit(FALSE);
+		return is_php('5.5')
+			? $this->conn_id->begin_transaction()
+			: $this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Field data query
-	 *
-	 * Generates a platform-specific query so that the column data can be retrieved
+	 * Commit Transaction
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @return	object
+	 * @return	bool
 	 */
-	function _field_data($table)
+	protected function _trans_commit()
 	{
-		return "DESCRIBE ".$table;
-	}
-
-	// --------------------------------------------------------------------
+		if ($this->conn_id->commit())
+		{
+			$this->conn_id->autocommit(TRUE);
+			return TRUE;
+		}
 
-	/**
-	 * The error message string
-	 *
-	 * @access	private
-	 * @return	string
-	 */
-	function _error_message()
-	{
-		return mysqli_error($this->conn_id);
+		return FALSE;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * The error message number
+	 * Rollback Transaction
 	 *
-	 * @access	private
-	 * @return	integer
+	 * @return	bool
 	 */
-	function _error_number()
+	protected function _trans_rollback()
 	{
-		return mysqli_errno($this->conn_id);
+		if ($this->conn_id->rollback())
+		{
+			$this->conn_id->autocommit(TRUE);
+			return TRUE;
+		}
+
+		return FALSE;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Escape the SQL Identifiers
-	 *
-	 * This function escapes column and table names
+	 * Platform-dependent string escape
 	 *
-	 * @access	private
 	 * @param	string
 	 * @return	string
 	 */
-	function _escape_identifiers($item)
+	protected function _escape_str($str)
 	{
-		if ($this->_escape_char == '')
-		{
-			return $item;
-		}
-
-		foreach ($this->_reserved_identifiers as $id)
-		{
-			if (strpos($item, '.'.$id) !== FALSE)
-			{
-				$str = $this->_escape_char. str_replace('.', $this->_escape_char.'.', $item);
-
-				// remove duplicates if the user already included the escape
-				return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
-			}
-		}
-
-		if (strpos($item, '.') !== FALSE)
-		{
-			$str = $this->_escape_char.str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item).$this->_escape_char;
-		}
-		else
-		{
-			$str = $this->_escape_char.$item.$this->_escape_char;
-		}
-
-		// remove duplicates if the user already included the escape
-		return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
+		return $this->conn_id->real_escape_string($str);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
+	 * Affected Rows
 	 *
-	 * @access	public
-	 * @param	type
-	 * @return	type
+	 * @return	int
 	 */
-	function _from_tables($tables)
+	public function affected_rows()
 	{
-		if ( ! is_array($tables))
-		{
-			$tables = array($tables);
-		}
-
-		return '('.implode(', ', $tables).')';
+		return $this->conn_id->affected_rows;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Insert statement
-	 *
-	 * Generates a platform-specific insert string from the supplied data
+	 * Insert ID
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
-	 * @return	string
+	 * @return	int
 	 */
-	function _insert($table, $keys, $values)
+	public function insert_id()
 	{
-		return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
+		return $this->conn_id->insert_id;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Insert_batch statement
+	 * List table query
 	 *
-	 * Generates a platform-specific insert string from the supplied data
+	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
-	function _insert_batch($table, $keys, $values)
+	protected function _list_tables($prefix_limit = FALSE)
 	{
-		return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES ".implode(', ', $values);
-	}
-
-	// --------------------------------------------------------------------
+		$sql = 'SHOW TABLES FROM '.$this->escape_identifiers($this->database);
 
+		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
+		{
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+		}
 
-	/**
-	 * Replace statement
-	 *
-	 * Generates a platform-specific replace string from the supplied data
-	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
-	 * @return	string
-	 */
-	function _replace($table, $keys, $values)
-	{
-		return "REPLACE INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
+		return $sql;
 	}
-	
+
 	// --------------------------------------------------------------------
 
 	/**
-	 * Update statement
+	 * Show column query
 	 *
-	 * Generates a platform-specific update string from the supplied data
+	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause
-	 * @param	array	the limit clause
+	 * @param	string	$table
 	 * @return	string
 	 */
-	function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
+	protected function _list_columns($table = '')
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key." = ".$val;
-		}
-
-		$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
-
-		$orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';
-
-		$sql = "UPDATE ".$table." SET ".implode(', ', $valstr);
-
-		$sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';
-
-		$sql .= $orderby.$limit;
-
-		return $sql;
+		return 'SHOW COLUMNS FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Update_Batch statement
-	 *
-	 * Generates a platform-specific batch update string from the supplied data
+	 * Returns an object with field data
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @return	string
+	 * @param	string	$table
+	 * @return	array
 	 */
-	function _update_batch($table, $values, $index, $where = NULL)
+	public function field_data($table)
 	{
-		$ids = array();
-		$where = ($where != '' AND count($where) >=1) ? implode(" ", $where).' AND ' : '';
-
-		foreach ($values as $key => $val)
+		if (($query = $this->query('SHOW COLUMNS FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE))) === FALSE)
 		{
-			$ids[] = $val[$index];
-
-			foreach (array_keys($val) as $field)
-			{
-				if ($field != $index)
-				{
-					$final[$field][] =  'WHEN '.$index.' = '.$val[$index].' THEN '.$val[$field];
-				}
-			}
+			return FALSE;
 		}
+		$query = $query->result_object();
 
-		$sql = "UPDATE ".$table." SET ";
-		$cases = '';
-
-		foreach ($final as $k => $v)
+		$retval = array();
+		for ($i = 0, $c = count($query); $i < $c; $i++)
 		{
-			$cases .= $k.' = CASE '."\n";
-			foreach ($v as $row)
-			{
-				$cases .= $row."\n";
-			}
-
-			$cases .= 'ELSE '.$k.' END, ';
-		}
+			$retval[$i]			= new stdClass();
+			$retval[$i]->name		= $query[$i]->Field;
 
-		$sql .= substr($cases, 0, -2);
+			sscanf($query[$i]->Type, '%[a-z](%d)',
+				$retval[$i]->type,
+				$retval[$i]->max_length
+			);
 
-		$sql .= ' WHERE '.$where.$index.' IN ('.implode(',', $ids).')';
+			$retval[$i]->default		= $query[$i]->Default;
+			$retval[$i]->primary_key	= (int) ($query[$i]->Key === 'PRI');
+		}
 
-		return $sql;
+		return $retval;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Truncate statement
+	 * Error
 	 *
-	 * Generates a platform-specific truncate string from the supplied data
-	 * If the database does not support the truncate() command
-	 * This function maps to "DELETE FROM table"
+	 * Returns an array containing code and message of the last
+	 * database error that has occurred.
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @return	string
+	 * @return	array
 	 */
-	function _truncate($table)
+	public function error()
 	{
-		return "TRUNCATE ".$table;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Delete statement
-	 *
-	 * Generates a platform-specific delete string from the supplied data
-	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	string	the limit clause
-	 * @return	string
-	 */
-	function _delete($table, $where = array(), $like = array(), $limit = FALSE)
-	{
-		$conditions = '';
-
-		if (count($where) > 0 OR count($like) > 0)
+		if ( ! empty($this->_mysqli->connect_errno))
 		{
-			$conditions = "\nWHERE ";
-			$conditions .= implode("\n", $this->ar_where);
-
-			if (count($where) > 0 && count($like) > 0)
-			{
-				$conditions .= " AND ";
-			}
-			$conditions .= implode("\n", $like);
+			return array(
+				'code'    => $this->_mysqli->connect_errno,
+				'message' => $this->_mysqli->connect_error
+			);
 		}
 
-		$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
-
-		return "DELETE FROM ".$table.$conditions.$limit;
+		return array('code' => $this->conn_id->errno, 'message' => $this->conn_id->error);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * FROM tables
 	 *
-	 * Generates a platform-specific LIMIT clause
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
 	 *
-	 * @access	public
-	 * @param	string	the sql query string
-	 * @param	integer	the number of rows to limit the query to
-	 * @param	integer	the offset value
 	 * @return	string
 	 */
-	function _limit($sql, $limit, $offset)
+	protected function _from_tables()
 	{
-		$sql .= "LIMIT ".$limit;
-
-		if ($offset > 0)
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
 		{
-			$sql .= " OFFSET ".$offset;
+			return '('.implode(', ', $this->qb_from).')';
 		}
 
-		return $sql;
+		return implode(', ', $this->qb_from);
 	}
 
 	// --------------------------------------------------------------------
@@ -759,18 +534,11 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Close DB Connection
 	 *
-	 * @access	public
-	 * @param	resource
 	 * @return	void
 	 */
-	function _close($conn_id)
+	protected function _close()
 	{
-		@mysqli_close($conn_id);
+		$this->conn_id->close();
 	}
 
-
 }
-
-
-/* End of file mysqli_driver.php */
-/* Location: ./system/database/drivers/mysqli/mysqli_driver.php */
\ No newline at end of file