<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @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
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * MySQLi Database Adapter Class - MySQLi only works with PHP 5
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the active record
 * class is being used or not.
 *
 * @package     CodeIgniter
 * @subpackage  Drivers
 * @category    Database
 * @author      ExpressionEngine Dev Team
 * @link        http://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 = '';

    /**
     * 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.
     */
    var $_count_string = "SELECT COUNT(*) AS ";
    var $_random_keyword = ' RAND()'; // database specific random keyword

    /**
     * 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
     */
    function db_connect()
    {
        if (!empty($GLOBALS['el_mysqli_connect'])) {
            return $GLOBALS['el_mysqli_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);
        }

    }

    // --------------------------------------------------------------------

    /**
     * Persistent database connection
     *
     * @access  private called by the base class
     * @return  resource
     */
    function db_pconnect()
    {
        return $this->db_connect();
    }

    // --------------------------------------------------------------------

    /**
     * Reconnect
     *
     * Keep / reestablish the db connection if no queries have been
     * sent for a length of time exceeding the server's idle timeout
     *
     * @access  public
     * @return  void
     */
    function reconnect()
    {
        if (mysqli_ping($this->conn_id) === FALSE)
        {
            $this->conn_id = FALSE;
        }
    }

    // --------------------------------------------------------------------

    /**
     * Select the database
     *
     * @access  private called by the base class
     * @return  resource
     */
    function db_select()
    {
        if (!empty($GLOBALS['el_mysqli_select_db'])) {
            return $GLOBALS['el_mysqli_select_db'];
        }

        return @mysqli_select_db($this->conn_id, $this->database);
    }

    // --------------------------------------------------------------------

    /**
     * Set client character set
     *
     * @access  private
     * @param   string
     * @param   string
     * @return  resource
     */
    function _db_set_charset($charset, $collation)
    {
        if ( ! isset($this->use_set_names))
        {
            // 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)."'");
        }
        else
        {
            return @mysqli_set_charset($this->conn_id, $charset);
        }
    }

    // --------------------------------------------------------------------

    /**
     * Version number query string
     *
     * @access  public
     * @return  string
     */
    function _version()
    {
        return "SELECT version() AS ver";
    }

    // --------------------------------------------------------------------

    /**
     * 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;
    }

    // --------------------------------------------------------------------

    /**
     * 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 (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
            {
                $sql = preg_replace("/^\s*DELETE\s+FROM\s+(\S+)\s*$/", "DELETE FROM \\1 WHERE 1=1", $sql);
            }
        }

        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * Begin Transaction
     *
     * @access  public
     * @return  bool
     */
    function trans_begin($test_mode = FALSE)
    {
        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;
        }

        // 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
     *
     * @access  public
     * @return  bool
     */
    function trans_commit()
    {
        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('COMMIT');
        $this->simple_query('SET AUTOCOMMIT=1');
        return TRUE;
    }

    // --------------------------------------------------------------------

    /**
     * Rollback Transaction
     *
     * @access  public
     * @return  bool
     */
    function trans_rollback()
    {
        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;
    }

    // --------------------------------------------------------------------

    /**
     * Escape String
     *
     * @access  public
     * @param   string
     * @param   bool    whether or not the string will be used in a LIKE condition
     * @return  string
     */
    function escape_str($str, $like = FALSE)
    {
        if (is_array($str))
        {
            foreach ($str as $key => $val)
            {
                $str[$key] = $this->escape_str($val, $like);
            }

            return $str;
        }

        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;
    }

    // --------------------------------------------------------------------

    /**
     * Affected Rows
     *
     * @access  public
     * @return  integer
     */
    function affected_rows()
    {
        return @mysqli_affected_rows($this->conn_id);
    }

    // --------------------------------------------------------------------

    /**
     * Insert ID
     *
     * @access  public
     * @return  integer
     */
    function insert_id()
    {
        return @mysqli_insert_id($this->conn_id);
    }

    // --------------------------------------------------------------------

    /**
     * "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
     *
     * Generates a platform-specific query string so that the table names can be fetched
     *
     * @access  private
     * @param   boolean
     * @return  string
     */
    function _list_tables($prefix_limit = FALSE)
    {
        $sql = "SHOW TABLES FROM ".$this->_escape_char.$this->database.$this->_escape_char;

        if ($prefix_limit !== FALSE AND $this->dbprefix != '')
        {
            $sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%'";
        }

        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * Show column query
     *
     * Generates a platform-specific query string so that the column names can be fetched
     *
     * @access  public
     * @param   string  the table name
     * @return  string
     */
    function _list_columns($table = '')
    {
        return "SHOW COLUMNS FROM ".$this->_protect_identifiers($table, TRUE, NULL, FALSE);
    }

    // --------------------------------------------------------------------

    /**
     * Field data query
     *
     * Generates a platform-specific query so that the column data can be retrieved
     *
     * @access  public
     * @param   string  the table name
     * @return  object
     */
    function _field_data($table)
    {
        return "DESCRIBE ".$table;
    }

    // --------------------------------------------------------------------

    /**
     * The error message string
     *
     * @access  private
     * @return  string
     */
    function _error_message()
    {
        return mysqli_error($this->conn_id);
    }

    // --------------------------------------------------------------------

    /**
     * The error message number
     *
     * @access  private
     * @return  integer
     */
    function _error_number()
    {
        return mysqli_errno($this->conn_id);
    }

    // --------------------------------------------------------------------

    /**
     * Escape the SQL Identifiers
     *
     * This function escapes column and table names
     *
     * @access  private
     * @param   string
     * @return  string
     */
    function _escape_identifiers($item)
    {
        if ($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);
    }

    // --------------------------------------------------------------------

    /**
     * From Tables
     *
     * This function implicitly groups FROM tables so there is no confusion
     * about operator precedence in harmony with SQL standards
     *
     * @access  public
     * @param   type
     * @return  type
     */
    function _from_tables($tables)
    {
        if ( ! is_array($tables))
        {
            $tables = array($tables);
        }

        return '('.implode(', ', $tables).')';
    }

    // --------------------------------------------------------------------

    /**
     * Insert statement
     *
     * Generates a platform-specific insert 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 _insert($table, $keys, $values)
    {
        return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
    }

    // --------------------------------------------------------------------

    /**
     * Insert_batch statement
     *
     * Generates a platform-specific insert 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 _insert_batch($table, $keys, $values)
    {
        return "INSERT INTO ".$table." (".implode(', ', $keys).") VALUES ".implode(', ', $values);
    }

    // --------------------------------------------------------------------


    /**
     * 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).")";
    }

    // --------------------------------------------------------------------

    /**
     * Update statement
     *
     * Generates a platform-specific update string from the supplied data
     *
     * @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
     * @return  string
     */
    function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
    {
        foreach ($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;
    }

    // --------------------------------------------------------------------

    /**
     * Update_Batch statement
     *
     * Generates a platform-specific batch update string from the supplied data
     *
     * @access  public
     * @param   string  the table name
     * @param   array   the update data
     * @param   array   the where clause
     * @return  string
     */
    function _update_batch($table, $values, $index, $where = NULL)
    {
        $ids = array();
        $where = ($where != '' AND count($where) >=1) ? implode(" ", $where).' AND ' : '';

        foreach ($values as $key => $val)
        {
            $ids[] = $val[$index];

            foreach (array_keys($val) as $field)
            {
                if ($field != $index)
                {
                    $final[$field][] =  'WHEN '.$index.' = '.$val[$index].' THEN '.$val[$field];
                }
            }
        }

        $sql = "UPDATE ".$table." SET ";
        $cases = '';

        foreach ($final as $k => $v)
        {
            $cases .= $k.' = CASE '."\n";
            foreach ($v as $row)
            {
                $cases .= $row."\n";
            }

            $cases .= 'ELSE '.$k.' END, ';
        }

        $sql .= substr($cases, 0, -2);

        $sql .= ' WHERE '.$where.$index.' IN ('.implode(',', $ids).')';

        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * Truncate statement
     *
     * 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"
     *
     * @access  public
     * @param   string  the table name
     * @return  string
     */
    function _truncate($table)
    {
        return "TRUNCATE ".$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)
        {
            $conditions = "\nWHERE ";
            $conditions .= implode("\n", $this->ar_where);

            if (count($where) > 0 && count($like) > 0)
            {
                $conditions .= " AND ";
            }
            $conditions .= implode("\n", $like);
        }

        $limit = ( ! $limit) ? '' : ' LIMIT '.$limit;

        return "DELETE FROM ".$table.$conditions.$limit;
    }

    // --------------------------------------------------------------------

    /**
     * Limit string
     *
     * Generates a platform-specific LIMIT clause
     *
     * @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)
    {
        $sql .= "LIMIT ".$limit;

        if ($offset > 0)
        {
            $sql .= " OFFSET ".$offset;
        }

        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * Close DB Connection
     *
     * @access  public
     * @param   resource
     * @return  void
     */
    function _close($conn_id)
    {
        @mysqli_close($conn_id);
    }


}


/* End of file mysqli_driver.php */
/* Location: ./system/database/drivers/mysqli/mysqli_driver.php */
