mysql.php

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        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);
    }

    // }}}
    // {{{ standaloneQuery()

   /**
     * execute a query as DBA
     *
     * @param string $query the SQL query
     * @param mixed   $types  array that contains the types of the columns in
     *                        the result set
     * @param boolean $is_manip  if the query is a manipulation query
     * @return mixed MDB2_OK on success, a MDB2 error on failure
     * @access public
     */
    function &standaloneQuery($query, $types = null, $is_manip = false)
    {
        $user = $this->options['DBA_username']? $this->options['DBA_username'] : $this->dsn['username'];
        $pass = $this->options['DBA_password']? $this->options['DBA_password'] : $this->dsn['password'];
        $connection = $this->_doConnect($user, $pass, $this->options['persistent']);
        if (PEAR::isError($connection)) {
            return $connection;
        }

        $offset = $this->offset;
        $limit = $this->limit;
        $this->offset = $this->limit = 0;
        $query = $this->_modifyQuery($query, $is_manip, $limit, $offset);
        
        $result =& $this->_doQuery($query, $is_manip, $connection, $this->database_name);
        if (!PEAR::isError($result)) {
            $result = $this->_affectedRows($connection, $result);
        }

        @mysql_close($connection);
        return $result;
    }

    // }}}
    // {{{ _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);
            }

            // LIMIT doesn't always come last in the query
            // @see http://dev.mysql.com/doc/refman/5.0/en/select.html
            $after = '';
            if (preg_match('/(\s+INTO\s+(?:OUT|DUMP)FILE\s.*)$/ims', $query, $matches)) {
                $after = $matches[0];
                $query = preg_replace('/(\s+INTO\s+(?:OUT|DUMP)FILE\s.*)$/ims', '', $query);
            } elseif (preg_match('/(\s+FOR\s+UPDATE\s*)$/i', $query, $matches)) {
               $after = $matches[0];
               $query = preg_replace('/(\s+FOR\s+UPDATE\s*)$/im', '', $query);
            } elseif (preg_match('/(\s+LOCK\s+IN\s+SHARE\s+MODE\s*)$/im', $query, $matches)) {
               $after = $matches[0];
               $query = preg_replace('/(\s+LOCK\s+IN\s+SHARE\s+MODE\s*)$/im', '', $query);
            }

            if ($is_manip) {
                return $query . " LIMIT $limit" . $after;
            } else {
                return $query . " LIMIT $offset, $limit" . $after;
            }
        }
        return $query;
    }

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

    /**
     * return version information about the server
     *
     * @param bool   $native  determines if the raw version string should be returned
     * @return mixed array/string with version information or MDB2 error object
     * @access public
     */
    function getServerVersion($native = false)
    {
        $connection = $this->getConnection();
        if (PEAR::isError($connection)) {
            return $connection;
        }
        if ($this->connected_server_info) {
            $server_info = $this->connected_server_info;
        } else {
            $server_info = @mysql_get_server_info($connection);
        }
        if (!$server_info) {
            return $this->raiseError(null, null, null,
                'Could not get server information', __FUNCTION__);
        }
        // cache server_info
        $this->connected_server_info = $server_info;
        if (!$native) {
            $tmp = explode('.', $server_info, 3);
            if (isset($tmp[2]) && strpos($tmp[2], '-')) {
                $tmp2 = explode('-', @$tmp[2], 2);
            } else {
                $tmp2[0] = isset($tmp[2]) ? $tmp[2] : null;
                $tmp2[1] = null;
            }
            $server_info = array(
                'major' => isset($tmp[0]) ? $tmp[0] : null,
                'minor' => isset($tmp[1]) ? $tmp[1] : null,
                'patch' => $tmp2[0],
                'extra' => $tmp2[1],
                'native' => $server_info,
            );
        }
        return $server_info;
    }

    // }}}
    // {{{ _getServerCapabilities()

    /**
     * Fetch some information about the server capabilities
     * (transactions, subselects, prepared statements, etc).
     *
     * @access private
     */
    function _getServerCapabilities()
    {
        if (!$this->server_capabilities_checked) {
            $this->server_capabilities_checked = true;

            //set defaults
            $this->supported['sub_selects'] = 'emulated';
            $this->supported['prepared_statements'] = 'emulated';
            $this->supported['triggers'] = false;
            $this->start_transaction = false;
            $this->varchar_max_length = 255;
            
            $server_info = $this->getServerVersion();
            if (is_array($server_info)) {
                $server_version = $server_info['major'].'.'.$server_info['minor'].'.'.$server_info['patch'];

                if (!version_compare($server_version, '4.1.0', '<')) {
                    $this->supported['sub_selects'] = true;
                    $this->supported['prepared_statements'] = true;
                }

                // SAVEPOINTs were introduced in MySQL 4.0.14 and 4.1.1 (InnoDB)
                if (version_compare($server_version, '4.1.0', '>=')) {
                    if (version_compare($server_version, '4.1.1', '<')) {
                        $this->supported['savepoints'] = false;
                    }
                } elseif (version_compare($server_version, '4.0.14', '<')) {
                    $this->supported['savepoints'] = false;
                }

                if (!version_compare($server_version, '4.0.11', '<')) {
                    $this->start_transaction = true;
                }

                if (!version_compare($server_version, '5.0.3', '<')) {
                    $this->varchar_max_length = 65532;
                }

                if (!version_compare($server_version, '5.0.2', '<')) {
                    $this->supported['triggers'] = true;
                }
            }
        }
    }

    // }}}
    // {{{ function _skipUserDefinedVariable($query, $position)

    /**
     * Utility method, used by prepare() to avoid misinterpreting MySQL user 
     * defined variables (SELECT @x:=5) for placeholders.
     * Check if the placeholder is a false positive, i.e. if it is an user defined
     * variable instead. If so, skip it and advance the position, otherwise
     * return the current position, which is valid
     *
     * @param string $query
     * @param integer $position current string cursor position
     * @return integer $new_position
     * @access protected
     */
    function _skipUserDefinedVariable($query, $position)
    {
        $found = strpos(strrev(substr($query, 0, $position)), '@');
        if ($found === false) {
            return $position;
        }
        $pos = strlen($query) - strlen(substr($query, $position)) - $found - 1;
        $substring = substr($query, $pos, $position - $pos + 2);
        if (preg_match('/^@\w+\s*:=$/', $substring)) {
            return $position + 1; //found an user defined variable: skip it
        }
        return $position;
    }

    // }}}
    // {{{ prepare()

    /**
     * Prepares a query for multiple execution with execute().
     * With some database backends, this is emulated.
     * prepare() requires a generic query as string like
     * 'INSERT INTO numbers VALUES(?,?)' or
     * 'INSERT INTO numbers VALUES(:foo,:bar)'.
     * The ? and :name and are placeholders which can be set using
     * bindParam() and the query can be sent off using the execute() method.
     * The allowed format for :name can be set with the 'bindname_format' option.
     *
     * @param string $query the query to prepare