Failed Conditions
Pull Request — master (#1922)
by chihiro
49:10 queued 16:45
created

LimitSubqueryWalker::walkSelectStatement()   B

Complexity

Conditions 7
Paths 9

Size

Total Lines 56
Code Lines 33

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 30
CRAP Score 7.0016

Importance

Changes 0
Metric Value
cc 7
eloc 33
nc 9
nop 1
dl 0
loc 56
ccs 30
cts 31
cp 0.9677
crap 7.0016
rs 7.7489
c 0
b 0
f 0

How to fix   Long Method   

Long Method

Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.

For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.

Commonly applied refactorings include:

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<?php
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/**
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 * Doctrine ORM
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 *
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 * LICENSE
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 *
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 * This source file is subject to the new BSD license that is bundled
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 * with this package in the file LICENSE. This license can also be viewed
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 * at http://hobodave.com/license.txt
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 *
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 * @category    DoctrineExtensions
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 * @package     DoctrineExtensions\Paginate
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 * @author      David Abdemoulaie <[email protected]>
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 * @copyright   Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
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 * @license     http://hobodave.com/license.txt New BSD License
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 */
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namespace Eccube\Doctrine\ORM\Tools\Pagination;
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use Doctrine\DBAL\Types\Type;
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use Doctrine\ORM\Mapping\ClassMetadataInfo;
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use Doctrine\ORM\ORMException;
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use Doctrine\ORM\Query;
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use Doctrine\ORM\Query\TreeWalkerAdapter;
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use Doctrine\ORM\Query\AST\Functions\IdentityFunction;
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use Doctrine\ORM\Query\AST\PathExpression;
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use Doctrine\ORM\Query\AST\SelectExpression;
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use Doctrine\ORM\Query\AST\SelectStatement;
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/**
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 * Replaces the selectClause of the AST with a SELECT DISTINCT root.id equivalent.
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 *
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 * @category    DoctrineExtensions
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 * @package     DoctrineExtensions\Paginate
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 * @author      David Abdemoulaie <[email protected]>
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 * @copyright   Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
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 * @license     http://hobodave.com/license.txt New BSD License
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 */
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class LimitSubqueryWalker extends TreeWalkerAdapter
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{
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    /**
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     * ID type hint.
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     */
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    const IDENTIFIER_TYPE = 'doctrine_paginator.id.type';
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    /**
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     * Counter for generating unique order column aliases.
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     *
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     * @var int
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     */
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    private $_aliasCounter = 0;
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    /**
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     * Walks down a SelectStatement AST node, modifying it to retrieve DISTINCT ids
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     * of the root Entity.
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     *
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     * @param SelectStatement $AST
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     *
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     * @return void
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     *
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     * @throws \RuntimeException
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     */
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    public function walkSelectStatement(SelectStatement $AST)
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    {
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        $queryComponents = $this->_getQueryComponents();
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        // Get the root entity and alias from the AST fromClause
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        $from      = $AST->fromClause->identificationVariableDeclarations;
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        $fromRoot  = reset($from);
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        $rootAlias = $fromRoot->rangeVariableDeclaration->aliasIdentificationVariable;
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        $rootClass = $queryComponents[$rootAlias]['metadata'];
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        $selectExpressions = array();
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        $this->validate($AST);
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        foreach ($queryComponents as $dqlAlias => $qComp) {
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            // Preserve mixed data in query for ordering.
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            if (isset($qComp['resultVariable'])) {
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                $selectExpressions[] = new SelectExpression($qComp['resultVariable'], $dqlAlias);
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                continue;
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            }
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        }
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84 11
        $identifier = $rootClass->getSingleIdentifierFieldName();
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86 11
        if (isset($rootClass->associationMappings[$identifier])) {
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            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.");
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        }
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        $this->_getQuery()->setHint(
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            self::IDENTIFIER_TYPE,
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            Type::getType($rootClass->getTypeOfField($identifier))
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        );
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        $pathExpression = new PathExpression(
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            PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION,
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            $rootAlias,
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            $identifier
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        );
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        $pathExpression->type = PathExpression::TYPE_STATE_FIELD;
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        array_unshift($selectExpressions, new SelectExpression($pathExpression, '_dctrn_id'));
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        $AST->selectClause->selectExpressions = $selectExpressions;
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        if (isset($AST->orderByClause)) {
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            foreach ($AST->orderByClause->orderByItems as $item) {
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                if ( ! $item->expression instanceof PathExpression) {
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                    continue;
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                }
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111 11
                $AST->selectClause->selectExpressions[] = new SelectExpression(
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                    $this->createSelectExpressionItem($item->expression),
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                    '_dctrn_ord' . $this->_aliasCounter++
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                );
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            }
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        }
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        $AST->selectClause->isDistinct = true;
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    }
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    /**
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     * Validate the AST to ensure that this walker is able to properly manipulate it.
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     *
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     * @param SelectStatement $AST
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     */
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    private function validate(SelectStatement $AST)
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    {
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        // Prevent LimitSubqueryWalker from being used with queries that include
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        // a limit, a fetched to-many join, and an order by condition that
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        // references a column from the fetch joined table.
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        $queryComponents = $this->getQueryComponents();
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        $query           = $this->_getQuery();
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        $from            = $AST->fromClause->identificationVariableDeclarations;
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        $fromRoot        = reset($from);
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        if ($query instanceof Query
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            && $query->getMaxResults()
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            && $AST->orderByClause
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            && count($fromRoot->joins)) {
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            // Check each orderby item.
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            // TODO: check complex orderby items too...
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            foreach ($AST->orderByClause->orderByItems as $orderByItem) {
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                $expression = $orderByItem->expression;
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                if ($orderByItem->expression instanceof PathExpression
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                    && isset($queryComponents[$expression->identificationVariable])) {
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                    $queryComponent = $queryComponents[$expression->identificationVariable];
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                    if (isset($queryComponent['parent'])
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                        && $queryComponent['relation']['type'] & ClassMetadataInfo::TO_MANY) {
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                        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.");
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                    }
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                }
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            }
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        }
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    }
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    /**
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     * Retrieve either an IdentityFunction (IDENTITY(u.assoc)) or a state field (u.name).
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     * 
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     * @param \Doctrine\ORM\Query\AST\PathExpression $pathExpression
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     * 
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     * @return \Doctrine\ORM\Query\AST\Functions\IdentityFunction
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     */
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    private function createSelectExpressionItem(PathExpression $pathExpression)
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    {
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        if ($pathExpression->type === PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION) {
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            $identity = new IdentityFunction('identity');
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            $identity->pathExpression = clone $pathExpression;
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            return $identity;
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        }
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173 11
        return clone $pathExpression;
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Bug Best Practice introduced by
The return type of return clone $pathExpression; (Doctrine\ORM\Query\AST\PathExpression) is incompatible with the return type documented by Eccube\Doctrine\ORM\Tool...ateSelectExpressionItem of type Doctrine\ORM\Query\AST\Functions\IdentityFunction.

If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.

Let’s take a look at an example:

class Author {
    private $name;

    public function __construct($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }
}

abstract class Post {
    public function getAuthor() {
        return 'Johannes';
    }
}

class BlogPost extends Post {
    public function getAuthor() {
        return new Author('Johannes');
    }
}

class ForumPost extends Post { /* ... */ }

function my_function(Post $post) {
    echo strtoupper($post->getAuthor());
}

Our function my_function expects a Post object, and outputs the author of the post. The base class Post returns a simple string and outputting a simple string will work just fine. However, the child class BlogPost which is a sub-type of Post instead decided to return an object, and is therefore violating the SOLID principles. If a BlogPost were passed to my_function, PHP would not complain, but ultimately fail when executing the strtoupper call in its body.

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    }
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}
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