mysql.php

This is the script which used on 10minutemail.com for temporary email.

     *
     * @access  public
     * @since   2.1.1
     */
    function setTransactionIsolation($isolation)
    {
        $this->debug('Setting transaction isolation level', __FUNCTION__, array('is_manip' => true));
        if (!$this->supports('transactions')) {
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'transactions are not supported', __FUNCTION__);
        }
        switch ($isolation) {
        case 'READ UNCOMMITTED':
        case 'READ COMMITTED':
        case 'REPEATABLE READ':
        case 'SERIALIZABLE':
            break;
        default:
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'isolation level is not supported: '.$isolation, __FUNCTION__);
        }

        $query = "SET SESSION TRANSACTION ISOLATION LEVEL $isolation";
        return $this->_doQuery($query, true);
    }

    // }}}
    // {{{ connect()

    /**
     * Connect to the database
     *
     * @return true on success, MDB2 Error Object on failure
     */
    function connect()
    {
        if (is_resource($this->connection)) {
            if (count(array_diff($this->connected_dsn, $this->dsn)) == 0
                && $this->opened_persistent == $this->options['persistent']
            ) {
                return MDB2_OK;
            }
            $this->disconnect(false);
        }

        if (!PEAR::loadExtension($this->phptype)) {
            return $this->raiseError(MDB2_ERROR_NOT_FOUND, null, null,
                'extension '.$this->phptype.' is not compiled into PHP', __FUNCTION__);
        }

        $params = array();
        if ($this->dsn['protocol'] && $this->dsn['protocol'] == 'unix') {
            $params[0] = ':' . $this->dsn['socket'];
        } else {
            $params[0] = $this->dsn['hostspec'] ? $this->dsn['hostspec']
                         : 'localhost';
            if ($this->dsn['port']) {
                $params[0].= ':' . $this->dsn['port'];
            }
        }
        $params[] = $this->dsn['username'] ? $this->dsn['username'] : null;
        $params[] = $this->dsn['password'] ? $this->dsn['password'] : null;
        if (!$this->options['persistent']) {
            if (isset($this->dsn['new_link'])
                && ($this->dsn['new_link'] == 'true' || $this->dsn['new_link'] === true)
            ) {
                $params[] = true;
            } else {
                $params[] = false;
            }
        }
        if (version_compare(phpversion(), '4.3.0', '>=')) {
            $params[] = isset($this->dsn['client_flags'])
                ? $this->dsn['client_flags'] : null;
        }
        $connect_function = $this->options['persistent'] ? 'mysql_pconnect' : 'mysql_connect';

        $connection = @call_user_func_array($connect_function, $params);
        if (!$connection) {
            if (($err = @mysql_error()) != '') {
                return $this->raiseError(MDB2_ERROR_CONNECT_FAILED, null, null,
                    $err, __FUNCTION__);
            } else {
                return $this->raiseError(MDB2_ERROR_CONNECT_FAILED, null, null,
                    'unable to establish a connection', __FUNCTION__);
            }
        }

        if (!empty($this->dsn['charset'])) {
            $result = $this->setCharset($this->dsn['charset'], $connection);
            if (PEAR::isError($result)) {
                return $result;
            }
        }

        $this->connection = $connection;
        $this->connected_dsn = $this->dsn;
        $this->connected_database_name = '';
        $this->opened_persistent = $this->options['persistent'];
        $this->dbsyntax = $this->dsn['dbsyntax'] ? $this->dsn['dbsyntax'] : $this->phptype;

        if ($this->database_name) {
            if ($this->database_name != $this->connected_database_name) {
                if (!@mysql_select_db($this->database_name, $connection)) {
                    $err = $this->raiseError(null, null, null,
                        'Could not select the database: '.$this->database_name, __FUNCTION__);
                    return $err;
                }
                $this->connected_database_name = $this->database_name;
            }
        }

        $this->supported['transactions'] = $this->options['use_transactions'];
        if ($this->options['default_table_type']) {
            switch (strtoupper($this->options['default_table_type'])) {
            case 'BLACKHOLE':
            case 'MEMORY':
            case 'ARCHIVE':
            case 'CSV':
            case 'HEAP':
            case 'ISAM':
            case 'MERGE':
            case 'MRG_ISAM':
            case 'ISAM':
            case 'MRG_MYISAM':
            case 'MYISAM':
                $this->supported['transactions'] = false;
                $this->warnings[] = $this->options['default_table_type'] .
                    ' is not a supported default table type';
                break;
            }
        }

        $this->supported['sub_selects'] = 'emulated';
        $this->supported['prepared_statements'] = 'emulated';
        $this->start_transaction = false;
        $this->varchar_max_length = 255;

        $server_info = $this->getServerVersion();
        if (is_array($server_info)) {
            if (!version_compare($server_info['major'].'.'.$server_info['minor'].'.'.$server_info['patch'], '4.1.0', '<')) {
                $this->supported['sub_selects'] = true;
                $this->supported['prepared_statements'] = true;
            }

            if (!version_compare($server_info['major'].'.'.$server_info['minor'].'.'.$server_info['patch'], '4.0.14', '<')
                || !version_compare($server_info['major'].'.'.$server_info['minor'].'.'.$server_info['patch'], '4.1.1', '<')
            ) {
                $this->supported['savepoints'] = true;
            }

            if (!version_compare($server_info['major'].'.'.$server_info['minor'].'.'.$server_info['patch'], '4.0.11', '<')) {
                $this->start_transaction = true;
            }

            if (!version_compare($server_info['major'].'.'.$server_info['minor'].'.'.$server_info['patch'], '5.0.3', '<')) {
                $this->varchar_max_length = 65532;
            }
        }

        return MDB2_OK;
    }
    // }}}
    // {{{ setCharset()

    /**
     * Set the charset on the current connection
     *
     * @param string    charset
     * @param resource  connection handle
     *
     * @return true on success, MDB2 Error Object on failure
     */
    function setCharset($charset, $connection = null)
    {
        if (is_null($connection)) {
            $connection = $this->getConnection();
            if (PEAR::isError($connection)) {
                return $connection;
            }
        }

        $query = "SET character_set_client = '".mysql_real_escape_string($charset, $connection)."'";
        $result = @mysql_query($query, $connection);
        if (!$result) {
            return $this->raiseError(null, null, null,
                'Unable to set client charset: '.$charset, __FUNCTION__);
        }

        return MDB2_OK;
    }

    // }}}
    // {{{ disconnect()

    /**
     * Log out and disconnect from the database.
     *
     * @param  boolean $force if the disconnect should be forced even if the
     *                        connection is opened persistently
     * @return mixed true on success, false if not connected and error
     *                object on error
     * @access public
     */
    function disconnect($force = true)
    {
        if (is_resource($this->connection)) {
            if ($this->in_transaction) {
                $dsn = $this->dsn;
                $database_name = $this->database_name;
                $persistent = $this->options['persistent'];
                $this->dsn = $this->connected_dsn;
                $this->database_name = $this->connected_database_name;
                $this->options['persistent'] = $this->opened_persistent;
                $this->rollback();
                $this->dsn = $dsn;
                $this->database_name = $database_name;
                $this->options['persistent'] = $persistent;
            }

            if (!$this->opened_persistent || $force) {
                @mysql_close($this->connection);
            }
        }
        return parent::disconnect($force);
    }

    // }}}
    // {{{ _doQuery()

    /**
     * Execute a query
     * @param string $query  query
     * @param boolean $is_manip  if the query is a manipulation query
     * @param resource $connection
     * @param string $database_name
     * @return result or error object
     * @access protected
     */
    function &_doQuery($query, $is_manip = false, $connection = null, $database_name = null)
    {
        $this->last_query = $query;
        $result = $this->debug($query, 'query', array('is_manip' => $is_manip, 'when' => 'pre'));
        if ($result) {
            if (PEAR::isError($result)) {
                return $result;
            }
            $query = $result;
        }
        if ($this->options['disable_query']) {
            $result = $is_manip ? 0 : null;
            return $result;
        }

        if (is_null($connection)) {
            $connection = $this->getConnection();
            if (PEAR::isError($connection)) {
                return $connection;
            }
        }
        if (is_null($database_name)) {
            $database_name = $this->database_name;
        }

        if ($database_name) {
            if ($database_name != $this->connected_database_name) {
                if (!@mysql_select_db($database_name, $connection)) {
                    $err = $this->raiseError(null, null, null,
                        'Could not select the database: '.$database_name, __FUNCTION__);
                    return $err;
                }
                $this->connected_database_name = $database_name;
            }
        }

        $function = $this->options['result_buffering']
            ? 'mysql_query' : 'mysql_unbuffered_query';
        $result = @$function($query, $connection);
        if (!$result) {
            $err =& $this->raiseError(null, null, null,
                'Could not execute statement', __FUNCTION__);
            return $err;
        }

        $this->debug($query, 'query', array('is_manip' => $is_manip, 'when' => 'post', 'result' => $result));
        return $result;
    }

    // }}}
    // {{{ _affectedRows()

    /**
     * Returns the number of rows affected
     *
     * @param resource $result
     * @param resource $connection
     * @return mixed MDB2 Error Object or the number of rows affected
     * @access private
     */
    function _affectedRows($connection, $result = null)
    {
        if (is_null($connection)) {
            $connection = $this->getConnection();
            if (PEAR::isError($connection)) {
                return $connection;
            }
        }
        return @mysql_affected_rows($connection);
    }

    // }}}
    // {{{ _modifyQuery()

    /**
     * Changes a query string for various DBMS specific reasons
     *
     * @param string $query  query to modify
     * @param boolean $is_manip  if it is a DML query
     * @param integer $limit  limit the number of rows
     * @param integer $offset  start reading from given offset
     * @return string modified query
     * @access protected
     */
    function _modifyQuery($query, $is_manip, $limit, $offset)
    {
        if ($this->options['portability'] & MDB2_PORTABILITY_DELETE_COUNT) {
            // "DELETE FROM table" gives 0 affected rows in MySQL.
            // This little hack lets you know how many rows were deleted.
            if (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $query)) {
                $query = preg_replace('/^\s*DELETE\s+FROM\s+(\S+)\s*$/',
                                      'DELETE FROM \1 WHERE 1=1', $query);
            }
        }
        if ($limit > 0
            && !preg_match('/LIMIT\s*\d(\s*(,|OFFSET)\s*\d+)?/i', $query)
        ) {
            $query = rtrim($query);
            if (substr($query, -1) == ';') {
                $query = substr($query, 0, -1);
            }
            if ($is_manip) {
                return $query . " LIMIT $limit";
            } else {
                return $query . " LIMIT $offset, $limit";
            }
        }
        return $query;
    }

    // }}}
    // {{{ getServerVersion()