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<?php
declare(strict_types=1);
namespace Doctrine\ORM\Tools\Pagination;
use Doctrine\DBAL\Types\Type;
use Doctrine\ORM\Mapping\ClassMetadata;
use Doctrine\ORM\Query;
use Doctrine\ORM\Query\AST\Functions\IdentityFunction;
use Doctrine\ORM\Query\AST\Node;
use Doctrine\ORM\Query\AST\PathExpression;
use Doctrine\ORM\Query\AST\SelectExpression;
use Doctrine\ORM\Query\AST\SelectStatement;
use Doctrine\ORM\Query\TreeWalkerAdapter;
use RuntimeException;
use function count;
use function is_string;
use function reset;
/**
* Replaces the selectClause of the AST with a SELECT DISTINCT root.id equivalent.
*/
class LimitSubqueryWalker extends TreeWalkerAdapter
{
public const IDENTIFIER_TYPE = 'doctrine_paginator.id.type';
public const FORCE_DBAL_TYPE_CONVERSION = 'doctrine_paginator.scalar_result.force_dbal_type_conversion';
/**
* Counter for generating unique order column aliases.
*
* @var int
*/
private $_aliasCounter = 0;
public function walkSelectStatement(SelectStatement $AST)
{
// Get the root entity and alias from the AST fromClause
$from = $AST->fromClause->identificationVariableDeclarations;
$fromRoot = reset($from);
$rootAlias = $fromRoot->rangeVariableDeclaration->aliasIdentificationVariable;
$rootClass = $this->getMetadataForDqlAlias($rootAlias);
$this->validate($AST);
$identifier = $rootClass->getSingleIdentifierFieldName();
if (isset($rootClass->associationMappings[$identifier])) {
throw new RuntimeException('Paginating an entity with foreign key as identifier only works when using the Output Walkers. Call Paginator#setUseOutputWalkers(true) before iterating the paginator.');
}
$this->_getQuery()->setHint(
self::IDENTIFIER_TYPE,
Type::getType($rootClass->fieldMappings[$identifier]['type'])
);
$this->_getQuery()->setHint(self::FORCE_DBAL_TYPE_CONVERSION, true);
$pathExpression = new PathExpression(
PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION,
$rootAlias,
$identifier
);
$pathExpression->type = PathExpression::TYPE_STATE_FIELD;
$AST->selectClause->selectExpressions = [new SelectExpression($pathExpression, '_dctrn_id')];
$AST->selectClause->isDistinct = true;
if (! isset($AST->orderByClause)) {
return;
}
$queryComponents = $this->_getQueryComponents();
foreach ($AST->orderByClause->orderByItems as $item) {
if ($item->expression instanceof PathExpression) {
$AST->selectClause->selectExpressions[] = new SelectExpression(
$this->createSelectExpressionItem($item->expression),
'_dctrn_ord' . $this->_aliasCounter++
);
continue;
}
if (is_string($item->expression) && isset($queryComponents[$item->expression])) {
$qComp = $queryComponents[$item->expression];
if (isset($qComp['resultVariable'])) {
$AST->selectClause->selectExpressions[] = new SelectExpression(
$qComp['resultVariable'],
$item->expression
);
}
}
}
}
/**
* Validate the AST to ensure that this walker is able to properly manipulate it.
*/
private function validate(SelectStatement $AST): void
{
// Prevent LimitSubqueryWalker from being used with queries that include
// a limit, a fetched to-many join, and an order by condition that
// references a column from the fetch joined table.
$queryComponents = $this->getQueryComponents();
$query = $this->_getQuery();
$from = $AST->fromClause->identificationVariableDeclarations;
$fromRoot = reset($from);
if (
$query instanceof Query
&& $query->getMaxResults() !== null
&& $AST->orderByClause
&& count($fromRoot->joins)
) {
// Check each orderby item.
// TODO: check complex orderby items too...
foreach ($AST->orderByClause->orderByItems as $orderByItem) {
$expression = $orderByItem->expression;
if (
$orderByItem->expression instanceof PathExpression
&& isset($queryComponents[$expression->identificationVariable])
) {
$queryComponent = $queryComponents[$expression->identificationVariable];
if (
isset($queryComponent['parent'])
&& isset($queryComponent['relation'])
&& $queryComponent['relation']['type'] & ClassMetadata::TO_MANY
) {
throw new RuntimeException('Cannot select distinct identifiers from query with LIMIT and ORDER BY on a column from a fetch joined to-many association. Use output walkers.');
}
}
}
}
}
/**
* Retrieve either an IdentityFunction (IDENTITY(u.assoc)) or a state field (u.name).
*
* @return IdentityFunction|PathExpression
*/
private function createSelectExpressionItem(PathExpression $pathExpression): Node
{
if ($pathExpression->type === PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION) {
$identity = new IdentityFunction('identity');
$identity->pathExpression = clone $pathExpression;
return $identity;
}
return clone $pathExpression;
}
}
|
