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doctrine2/lib/Doctrine/ORM/Tools/Pagination/CountWalker.php
2012-03-24 11:16:32 +01:00

85 lines
2.8 KiB
PHP

<?php
/**
* Doctrine ORM
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to kontakt@beberlei.de so I can send you a copy immediately.
*/
namespace Doctrine\ORM\Tools\Pagination;
use Doctrine\ORM\Query\TreeWalkerAdapter,
Doctrine\ORM\Query\AST\SelectStatement,
Doctrine\ORM\Query\AST\SelectExpression,
Doctrine\ORM\Query\AST\PathExpression,
Doctrine\ORM\Query\AST\AggregateExpression;
/**
* Replaces the selectClause of the AST with a COUNT statement
*
* @category DoctrineExtensions
* @package DoctrineExtensions\Paginate
* @author David Abdemoulaie <dave@hobodave.com>
* @copyright Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
* @license http://hobodave.com/license.txt New BSD License
*/
class CountWalker extends TreeWalkerAdapter
{
/**
* Distinct mode hint name
*/
const HINT_DISTINCT = 'doctrine_paginator.distinct';
/**
* Walks down a SelectStatement AST node, modifying it to retrieve a COUNT
*
* @param SelectStatement $AST
* @return void
*/
public function walkSelectStatement(SelectStatement $AST)
{
if ($AST->havingClause) {
throw new \RuntimeException('Cannot count query that uses a HAVING clause. Use the output walkers for pagination');
}
$rootComponents = array();
foreach ($this->_getQueryComponents() as $dqlAlias => $qComp) {
$isParent = array_key_exists('parent', $qComp)
&& $qComp['parent'] === null
&& $qComp['nestingLevel'] == 0
;
if ($isParent) {
$rootComponents[] = array($dqlAlias => $qComp);
}
}
if (count($rootComponents) > 1) {
throw new \RuntimeException("Cannot count query which selects two FROM components, cannot make distinction");
}
$root = reset($rootComponents);
$parentName = key($root);
$parent = current($root);
$pathExpression = new PathExpression(
PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION, $parentName,
$parent['metadata']->getSingleIdentifierFieldName()
);
$pathExpression->type = PathExpression::TYPE_STATE_FIELD;
$distinct = $this->_getQuery()->getHint(self::HINT_DISTINCT);
$AST->selectClause->selectExpressions = array(
new SelectExpression(
new AggregateExpression('count', $pathExpression, $distinct), null
)
);
// ORDER BY is not needed, only increases query execution through unnecessary sorting.
$AST->orderByClause = null;
}
}