KjwXmlSql.php

<?php // vim:ts=4:sw=4:noet

/* (mydb/mytable.xml)

<?xml version="1.0" encoding="UTF-8"?>
<table name="mytable">
  <description>
    <column type="serial" name="id" next="5"/>
    <column type="string" name="name"/>
    <column type="string" name="destination"/>
    <column type="number" name="year"/>
  </description>
  <data>
    <row><col>1</col><col>Pietsje L</col><col>Leeuwarden</col><col>1983</col></row>
    <row><col>2</col><col>Klaasje L</col><col>Leeuwarden</col><col>1982</col></row>
    <row><col>3</col><col></col><col>Groningen</col><col>1983</col></row>
    <row><col>4</col><col>Thomas A</col><col>Anderlecht</col><col>1982</col></row>
  </data>
</table>
*/

/* (example.php)

$sql = kjwsql_from_url('xmlsql://localhost/mydb');
print_r($sql->selectAll("* FROM mytable order by destination, id desc limit 1,2"));
*/

if (!function_exists('xml_parser_create'))
        trigger_error('xml_* functions not defined.', E_USER_ERROR);
require_once(dirname(__FILE__) . '/KjwFakeSql.php');
require_once(dirname(__FILE__) . '/KjwArrayResultSet.php');

class KjwXmlSql extends KjwFakeSql {
        var $_dbpath = null;
        var $_last_insert_id = null;

        function KjwXmlSql($server, $unused_port, $unused_user, $unused_pass, $path) {
                assert('$server == "localhost" && $unused_port === 0 && $unused_user == "" && $unused_pass == ""');
                if (substr($path, -1) != '/')
                        $path .= '/';
                parent::KjwFakeSql('xmlsql', $server, $unused_port, $unused_user, $unused_pass, $path . 'lock');
                $this->_dbpath = $path;
        }

/*
        function updateArray($table, $args, $where = null) {
                $this->croak('Database Data Transfer Failure', 'implement me');
        }
*/

        function insertId() {
                return $this->_last_insert_id;
        }

        function _simpleSelect($table, $columns, $order, $skip = 0, $max = -1) {
                $obj = new KjwXmlSqlTable($table, $this->_dbpath);
                $obj->sort($order);
                $resultSet = $obj->getResultSet($skip, $max);
                $obj->destroy();
                return $resultSet;
        }

        function _simpleInsert($table, $args) {
                $this->_last_insert_id = 0;
                $obj = new KjwXmlSqlTable($table, $this->_dbpath);

                // Args without keys => columnless insert
                if (array_key_exists(0, $args)) {
                        
                        if (sizeof($args) != sizeof($obj->_description))
                                $this->croak('Database Data Transfer Failure', 'Value count mismatches column count');
                        $values = $args;
                // Args with keys => rewrite to array
                } else {
                        $values = array();
                        foreach ($args as $key => $value) {
                                for ($i = 0; $i < sizeof($obj->_description); ++$i) {
                                        if ($obj->_description[$i]['name'] == $key) {
                                                $values[$i] = $value;
                                                break;
                                        }
                                }
                        }
                        if (sizeof($values) != sizeof($args))
                                $this->croak('Database Data Transfer Failure', 'Trying to write to non-existent columns?');
                        for ($i = 0; $i < sizeof($obj->_description); ++$i) {
                                if (!isset($values[$i]))
                                        $values[$i] = null;
                                if ($obj->_description[$i]['type'] == 'serial' && $values[$i] === null)
                                        $this->_last_insert_id = $values[$i] = $obj->_description[$i]['next']++;
                        }
                        ksort($values); // fix our unordered array insert
                }

                // Convert nulls in serial columns to 'next'
                for ($i = 0; $i < sizeof($obj->_description); ++$i) {
                        if ($obj->_description[$i]['type'] == 'serial' && $values[$i] === null)
                                $this->_last_insert_id = $values[$i] = $obj->_description[$i]['next']++;
                }

                // Add the values to the end of the data
                array_push($obj->_data, $values);
                $obj->store($table);
                $obj->destroy();
        }

}

class KjwXmlSqlTable extends KjwObject {
        function KjwXmlSqlTable($tableName, $dbPath) {
                parent::KjwObject();
                $this->_tableName = $tableName;
                $this->_tableFile = $dbPath . $tableName . '.xml';
                $this->_state = 'root';

                $parser = xml_parser_create();
                xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, false);
                xml_set_object($parser, &$this);
                xml_set_element_handler($parser, 'onBeginElement', 'onEndElement');
                xml_set_character_data_handler($parser, 'onData');

                $fp = fopen($this->_tableFile, "rb"); // XXX mooie croaks als het misgaat
                while (($data = fread($fp, 8192)) !== '') {
                        if (!xml_parse($parser, $data, feof($fp)))
                                $this->croak('Database Data Transfer Failure', 'Xml parsing failed!');
                }
                fclose($fp);
                xml_parser_free($parser);
        }

        function sort($columnOrder) {
                $this->_setColumnOrder($columnOrder);
                $ret = usort($this->_data, array($this, 'cmp'));
                assert('$ret == true');
                unset($this->_columnOrder);
        }

        function onBeginElement($parser, $name, $attributes) {
                if ($this->_state == 'root' && $name == 'table') {
                        if ($attributes['name'] != $this->_tableName)
                                $this->croak('Database Data Transfer Failure', 'Table name missing or invalid');
                        $this->_state = 'table';
                } elseif ($this->_state == 'table' && $name == 'description') {
                        if (isset($this->_description))
                                $this->croak('Database Data Transfer Failure', 'Got description already');
                        $this->_state = 'description';
                        $this->_description = array();
                } elseif ($this->_state == 'description' && $name == 'column') {
                        if (!isset($attributes['type']) || !isset($attributes['name']))
                                $this->croak('Database Data Transfer Failure', 'Description lacks type or name');
                        array_push($this->_description, $attributes);
                } elseif ($this->_state == 'table' && $name == 'data') {
                        if (!isset($this->_description))
                                $this->croak('Database Data Transfer Failure', 'Data found before description.');
                        $this->_state = 'data';
                        $this->_data = array();
                } elseif ($this->_state == 'data' && $name == 'row') {
                        $this->_state = 'data_row';
                        $this->_tmp_row = array();
                } elseif ($this->_state == 'data_row' && $name == 'col') {
                        if (@$attributes['null']) {
                                $this->_state = 'data_column_null';
                                array_push($this->_tmp_row, null);
                        } else {
                                $this->_state = 'data_column';
                                array_push($this->_tmp_row, '');
                        }
                } else {
                        $this->croak('Database Data Transfer Failure', 'Unexpected element: ' . $this->_state . '/' . $name);
                }
        }

        function onEndElement($parser, $name) {
                if ($this->_state == 'table' && $name == 'table') {
                        $this->_state = 'root';
                } elseif ($this->_state == 'description' && $name == 'description') {
                        $this->_state = 'table';
                } elseif ($this->_state == 'description' && $name == 'column') {
                        ;
                } elseif ($this->_state == 'data' && $name == 'data') {
                        $this->_state = 'table';
                } elseif (($this->_state == 'data_column' || $this->_state == 'data_column_null')
                                && $name == 'col') {
                        $this->_state = 'data_row';
                } elseif ($this->_state == 'data_row' && $name == 'row') {
                        $this->_state = 'data';
                        array_push($this->_data, array_map(array($this, 'cast'), $this->_tmp_row, array_keys($this->_tmp_row)));
                        unset($this->_tmp_row);
                } else {
                        $this->croak('Database Data Transfer Failure', 'Unexpected element: ' . $this->_state . '/' . $name);
                }
        }

        function onData($parser, $data) {
                if ($this->_state == 'data_column') {
                        $this->_tmp_row[sizeof($this->_tmp_row)-1] .= $data;
                } elseif ($this->_state == 'data_column_null') {
                        ; // Nothing, is already null
                } elseif (trim($data) != '') {
                        $this->croak('Database Data Transfer Failure', $this->_state . ' - ' . $data);
                }
        }

        function cast($data, $column) {
                $type = $this->_description[$column]['type'];
                switch ($type) {
                case 'serial': return (int)$data;
                case 'string': return (string)$data;
                case 'number': return (float)$data;
                default: $this->croak('Database Data Transfer Failure', "Unknown data type $type");
                }
        }

        function getResultSet($skip = 0, $max = -1) {
                $arr = array();
                foreach ($this->_data as $k => $v) {
                        if ($skip-- > 0)
                                continue;
                        if ($max-- == 0)
                                break;
                        $dict = array();
                        for ($i = 0; $i < sizeof($this->_description); ++$i)
                                $dict[$this->_description[$i]['name']] = $v[$i];
                        array_push($arr, $dict);
                }
                return new KjwArrayResultSet($arr);
        }

        function store() {
                $fp = fopen($this->_tableFile, 'wb');
                fwrite($fp, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
                fwrite($fp, "<table name=\"" . htmlentities($this->_tableName, ENT_COMPAT, 'UTF-8') . "\">\n  <description>\n");
                foreach ($this->_description as $column) {
                        fwrite($fp, "    <column");
                        foreach ($column as $key => $value)
                                fwrite($fp, " $key=\"" . htmlentities($value, ENT_COMPAT, 'UTF-8') . "\"");
                        fwrite($fp, "/>\n");
                }
                fwrite($fp, "  </description>\n  <data>\n");
                foreach ($this->_data as $row) {
                        fwrite($fp, "    <row>");
                        foreach ($row as $column) {
                                if ($column === null)
                                        fwrite($fp, "<col null=\"1\"/>");
                                else
                                        fwrite($fp, "<col>" . htmlentities($column, ENT_COMPAT, 'UTF-8') . "</col>");
                        }
                        fwrite($fp, "</row>\n");
                }
                fwrite($fp, "  </data>\n</table>\n");
        }

    function cmp($a, $b) {
        foreach ($this->_sortOrder as $column => $asc) {
            if (($ret = $this->_primitive_compare($a[$column], $b[$column])) != 0)
                return $asc * $ret;
        }
        return 0;
    }

        function _setColumnOrder($order) {
                $column_order = array();
                foreach ($order as $column) {
                        $asc = 1;
                        if ($column[0] == '+') {
                                $column = substr($column, 1);
                        } elseif ($column[0] == '-') {
                                $column = substr($column, 1);
                                $asc = -1;
                        }
                        $column_pos = -1;
                        for ($i = 0; $i < sizeof($this->_description); ++$i) {
                                if ($this->_description[$i]['name'] == $column) {
                                        $column_pos = $i;
                                        break;
                                }
                        }
                        if ($column_pos == -1 || isset($column_order[$column_pos]))
                                continue;
                        $column_order[$column_pos] = $asc;
                }
                $this->_sortOrder = $column_order;
        }

    function _primitive_compare($a, $b) {
                if ($a === $b)
                        return 0;
        if (is_null($a) && !is_null($b))
            return 1; // null sorts later.. this is implementation dependent in sql
        if (is_null($b))
            return -1;
        if (is_int($a) or is_float($a))
            return $a < $b ? -1 : ($a == $b ? 0 : 1);
        if (is_string($a))
            return strcasecmp($a, $b);
                assert('false');
    }
}

?>

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