LimitSubqueryWalker   A
last analyzed

Complexity

Total Complexity 19

Size/Duplication

Total Lines 136
Duplicated Lines 0 %

Coupling/Cohesion

Components 1
Dependencies 11

Test Coverage

Coverage 92.59%

Importance

Changes 0
Metric Value
dl 0
loc 136
ccs 50
cts 54
cp 0.9259
rs 10
c 0
b 0
f 0
wmc 19
lcom 1
cbo 11

3 Methods

Rating   Name   Duplication   Size   Complexity  
B walkSelectStatement() 0 56 7
D validate() 0 29 10
A createSelectExpressionItem() 0 12 2
1
<?php
2
3
/**
4
 * Doctrine ORM
5
 *
6
 * LICENSE
7
 *
8
 * This source file is subject to the new BSD license that is bundled
9
 * with this package in the file LICENSE. This license can also be viewed
10
 * at http://hobodave.com/license.txt
11
 *
12
 * @category    DoctrineExtensions
13
 * @package     DoctrineExtensions\Paginate
14
 * @author      David Abdemoulaie <[email protected]>
15
 * @copyright   Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
16
 * @license     http://hobodave.com/license.txt New BSD License
17
 */
18
19
namespace Eccube\Doctrine\ORM\Tools\Pagination;
20
21
use Doctrine\DBAL\Types\Type;
22
use Doctrine\ORM\Mapping\ClassMetadataInfo;
23
use Doctrine\ORM\ORMException;
24
use Doctrine\ORM\Query;
25
use Doctrine\ORM\Query\TreeWalkerAdapter;
26
use Doctrine\ORM\Query\AST\Functions\IdentityFunction;
27
use Doctrine\ORM\Query\AST\PathExpression;
28
use Doctrine\ORM\Query\AST\SelectExpression;
29
use Doctrine\ORM\Query\AST\SelectStatement;
30
31
/**
32
 * Replaces the selectClause of the AST with a SELECT DISTINCT root.id equivalent.
33
 *
34
 * @category    DoctrineExtensions
35
 * @package     DoctrineExtensions\Paginate
36
 * @author      David Abdemoulaie <[email protected]>
37
 * @copyright   Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
38
 * @license     http://hobodave.com/license.txt New BSD License
39
 */
40
class LimitSubqueryWalker extends TreeWalkerAdapter
41
{
42
    /**
43
     * ID type hint.
44
     */
45
    const IDENTIFIER_TYPE = 'doctrine_paginator.id.type';
46
47
    /**
48
     * Counter for generating unique order column aliases.
49
     *
50
     * @var int
51
     */
52
    private $_aliasCounter = 0;
53
54
    /**
55
     * Walks down a SelectStatement AST node, modifying it to retrieve DISTINCT ids
56
     * of the root Entity.
57
     *
58
     * @param SelectStatement $AST
59
     *
60
     * @return void
61
     *
62
     * @throws \RuntimeException
63
     */
64 25
    public function walkSelectStatement(SelectStatement $AST)
65
    {
66 25
        $queryComponents = $this->_getQueryComponents();
67
        // Get the root entity and alias from the AST fromClause
68 25
        $from      = $AST->fromClause->identificationVariableDeclarations;
69 25
        $fromRoot  = reset($from);
70 25
        $rootAlias = $fromRoot->rangeVariableDeclaration->aliasIdentificationVariable;
71 25
        $rootClass = $queryComponents[$rootAlias]['metadata'];
72 25
        $selectExpressions = array();
73
74 25
        $this->validate($AST);
75
76 25
        foreach ($queryComponents as $dqlAlias => $qComp) {
77
            // Preserve mixed data in query for ordering.
78 25
            if (isset($qComp['resultVariable'])) {
79 4
                $selectExpressions[] = new SelectExpression($qComp['resultVariable'], $dqlAlias);
80 25
                continue;
81
            }
82
        }
83
        
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
84 25
        $identifier = $rootClass->getSingleIdentifierFieldName();
85
        
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
86 25
        if (isset($rootClass->associationMappings[$identifier])) {
87
            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.");
88
        }
89
90 25
        $this->_getQuery()->setHint(
91 25
            self::IDENTIFIER_TYPE,
92 25
            Type::getType($rootClass->getTypeOfField($identifier))
93
        );
94
95 25
        $pathExpression = new PathExpression(
96 25
            PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION,
97
            $rootAlias,
98
            $identifier
99
        );
100 25
        $pathExpression->type = PathExpression::TYPE_STATE_FIELD;
101
102 25
        array_unshift($selectExpressions, new SelectExpression($pathExpression, '_dctrn_id'));
103 25
        $AST->selectClause->selectExpressions = $selectExpressions;
104
105 25
        if (isset($AST->orderByClause)) {
106 25
            foreach ($AST->orderByClause->orderByItems as $item) {
107 25
                if ( ! $item->expression instanceof PathExpression) {
108 4
                    continue;
109
                }
110
                
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
111 25
                $AST->selectClause->selectExpressions[] = new SelectExpression(
112 25
                    $this->createSelectExpressionItem($item->expression),
113 25
                    '_dctrn_ord' . $this->_aliasCounter++
0 ignored issues
show
Coding Style introduced by
Concat operator must not be surrounded by spaces
Loading history...
114
                );
115
            }
116
        }
117
118 25
        $AST->selectClause->isDistinct = true;
119
    }
120
121
    /**
122
     * Validate the AST to ensure that this walker is able to properly manipulate it.
123
     *
124
     * @param SelectStatement $AST
125
     */
126 25
    private function validate(SelectStatement $AST)
127
    {
128
        // Prevent LimitSubqueryWalker from being used with queries that include
129
        // a limit, a fetched to-many join, and an order by condition that
130
        // references a column from the fetch joined table.
131 25
        $queryComponents = $this->getQueryComponents();
132 25
        $query           = $this->_getQuery();
133 25
        $from            = $AST->fromClause->identificationVariableDeclarations;
134 25
        $fromRoot        = reset($from);
135
136 25
        if ($query instanceof Query
137 25
            && $query->getMaxResults()
138 25
            && $AST->orderByClause
139 25
            && count($fromRoot->joins)) {
140
            // Check each orderby item.
141
            // TODO: check complex orderby items too...
142 6
            foreach ($AST->orderByClause->orderByItems as $orderByItem) {
143 6
                $expression = $orderByItem->expression;
144 6
                if ($orderByItem->expression instanceof PathExpression
145 6
                    && isset($queryComponents[$expression->identificationVariable])) {
146 6
                    $queryComponent = $queryComponents[$expression->identificationVariable];
147 6
                    if (isset($queryComponent['parent'])
148 6
                        && $queryComponent['relation']['type'] & ClassMetadataInfo::TO_MANY) {
149 6
                        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.");
150
                    }
151
                }
152
            }
153
        }
154
    }
155
    
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
156
    /**
157
     * Retrieve either an IdentityFunction (IDENTITY(u.assoc)) or a state field (u.name).
158
     * 
159
     * @param \Doctrine\ORM\Query\AST\PathExpression $pathExpression
160
     * 
161
     * @return \Doctrine\ORM\Query\AST\Functions\IdentityFunction
162
     */
163 25
    private function createSelectExpressionItem(PathExpression $pathExpression)
164
    {
165 25
        if ($pathExpression->type === PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION) {
166
            $identity = new IdentityFunction('identity');
167
            
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
168
            $identity->pathExpression = clone $pathExpression;
169
            
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
170
            return $identity;
171
        }
172
        
0 ignored issues
show
introduced by
Please trim any trailing whitespace
Loading history...
173 25
        return clone $pathExpression;
0 ignored issues
show
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.

Loading history...
174
    }
175
}
176