Source of file QueryParser.php

<?php declare(strict_types=1);

/**

 * Query

 *

 * SQL Query Builder / Database Abstraction Layer

 *

 * PHP version 7.1

 *

 * @package     Query

 * @author      Timothy J. Warren <tim@timshomepage.net>

 * @copyright   2012 - 2018 Timothy J. Warren

 * @license     http://www.opensource.org/licenses/mit-license.html  MIT License

 * @link        https://git.timshomepage.net/aviat4ion/Query

 */

namespace Query;

use Query\Drivers\DriverInterface;

/**

 * Utility Class to parse sql clauses for properly escaping identifiers

 */

class QueryParser {

	/**

	 * DB Driver

	 *

	 * @var DriverInterface

	 */

	private $db;

	/**

	 * Regex patterns for various syntax components

	 *

	 * @var array

	 */

	private $matchPatterns = [

		'function' => '([a-zA-Z0-9_]+\((.*?)\))',

		'identifier' => '([a-zA-Z0-9_-]+\.?)+',

		'operator' => '=|AND|&&?|~|\|\|?|\^|/|>=?|<=?|-|%|OR|\+|NOT|\!=?|<>|XOR'

	];

	/**

	 * Regex matches

	 *

	 * @var array

	 */

	public $matches = [

		'functions' => [],

		'identifiers' => [],

		'operators' => [],

		'combined' => [],

	];

	/**

	 * Constructor/entry point into parser

	 *

	 * @param DriverInterface $db

	 */

	public function __construct(DriverInterface $db)

	{

		$this->db = $db;

	}

	/**

	 * Parser method for setting the parse string

	 *

	 * @param string $sql

	 * @return array

	 */

	public function parseJoin(string $sql): array

	{

		// Get sql clause components

		preg_match_all('`'.$this->matchPatterns['function'].'`', $sql, $this->matches['functions'], PREG_SET_ORDER);

		preg_match_all('`'.$this->matchPatterns['identifier'].'`', $sql, $this->matches['identifiers'], PREG_SET_ORDER);

		preg_match_all('`'.$this->matchPatterns['operator'].'`', $sql, $this->matches['operators'], PREG_SET_ORDER);

		// Get everything at once for ordering

		$fullPattern = '`'.$this->matchPatterns['function'].'+|'.$this->matchPatterns['identifier'].'|('.$this->matchPatterns['operator'].')+`i';

		preg_match_all($fullPattern, $sql, $this->matches['combined'], PREG_SET_ORDER);

		// Go through the matches, and get the most relevant matches

		$this->matches = array_map([$this, 'filterArray'], $this->matches);

		return $this->matches;

	}

	/**

	 * Compiles a join condition after parsing

	 *

	 * @param string $condition

	 * @return string

	 */

	public function compileJoin(string $condition): string

	{

		$parts = $this->parseJoin($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] = $this->db->quoteIdent($parts['combined'][$i]);

			}

		}

		return implode('', $parts['combined']);

	}

	/**

	 * Returns a more useful match array

	 *

	 * @param array $array

	 * @return array

	 */

	protected function filterArray(array $array): array

	{

		$newArray = [];

		foreach($array as $row)

		{

			$newArray[] =  (is_array($row)) ? $row[0] : $row;

		}

		return $newArray;

	}

}