Query/docs/files/core/query_parser.php.txt
2014-04-24 11:25:12 -04:00

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<?php
/**
* Query
*
* Free Query Builder / Database Abstraction Layer
*
* @package Query
* @author Timothy J. Warren
* @copyright Copyright (c) 2012 - 2014
* @link https://github.com/aviat4ion/Query
* @license http://philsturgeon.co.uk/code/dbad-license
*/
// --------------------------------------------------------------------------
namespace Query;
/**
* Utility Class to parse sql clauses for properly escaping identifiers
*
* @package Query
* @subpackage Query_Builder
*/
class Query_Parser {
/**
* DB Driver
*
* @var \Query\Driver\Driver_Interface
*/
private $db;
/**
* Regex patterns for various syntax components
*
* @var array
*/
private $match_patterns = array(
'function' => '([a-zA-Z0-9_]+\((.*?)\))',
'identifier' => '([a-zA-Z0-9_-]+\.?)+',
'operator' => '=|AND|&&?|~|\|\|?|\^|/|>=?|<=?|-|%|OR|\+|NOT|\!=?|<>|XOR'
);
/**
* Regex matches
*
* @var array
*/
public $matches = array(
'functions' => array(),
'identifiers' => array(),
'operators' => array(),
'combined' => array(),
);
/**
* Constructor/entry point into parser
*
* @param Driver\Driver_Interface $db
*/
public function __construct(Driver\Driver_Interface $db)
{
$this->db = $db;
}
// --------------------------------------------------------------------------
/**
* Public parser method for setting the parse string
*
* @param string $sql
* @return array
*/
protected function parse_join($sql)
{
// Get sql clause components
preg_match_all('`'.$this->match_patterns['function'].'`', $sql, $this->matches['functions'], PREG_SET_ORDER);
preg_match_all('`'.$this->match_patterns['identifier'].'`', $sql, $this->matches['identifiers'], PREG_SET_ORDER);
preg_match_all('`'.$this->match_patterns['operator'].'`', $sql, $this->matches['operators'], PREG_SET_ORDER);
// Get everything at once for ordering
$full_pattern = '`'.$this->match_patterns['function'].'+|'.$this->match_patterns['identifier'].'|('.$this->match_patterns['operator'].')+`i';
preg_match_all($full_pattern, $sql, $this->matches['combined'], PREG_SET_ORDER);
// Go through the matches, and get the most relevant matches
$this->matches = array_map(array($this, 'filter_array'), $this->matches);
return $this->matches;
}
// --------------------------------------------------------------------------
/**
* Compiles a join condition after parsing
*
* @param string $condition
* @return string
*/
public function compile_join($condition)
{
$parts = $this->parse_join($condition);
$count = count($parts['identifiers']);
// Go through and quote the identifiers
for($i=0; $i <= $count; $i++)
{
if (in_array($parts['combined'][$i], $parts['identifiers']) && ! is_numeric($parts['combined'][$i]))
{
$parts['combined'][$i] = $this->db->quote_ident($parts['combined'][$i]);
}
}
return implode('', $parts['combined']);
}
// --------------------------------------------------------------------------
/**
* Returns a more useful match array
*
* @param array $array
* @return array
*/
protected function filter_array($array)
{
$new_array = array();
foreach($array as $row)
{
$new_array[] = (is_array($row)) ? $row[0] : $row;
}
return $new_array;
}
}
// End of query_parser.php