feature #1006 Added a Paginator object based on Doctrine's paginator (javiereguiluz)

This PR was squashed before being merged into the master branch (closes #1006).

Discussion
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Added a Paginator object based on Doctrine's paginator

The current code uses an array to provide the pagination information. We did that as part of the quick proof-of-concept replacement of Pagerfanta library.

This PR proposes to replace that array by a proper object. The new design was based on the one proposed by EasyAdmin to also replace Pagerfanta (EasyCorp/EasyAdminBundle#2777).

Commits
-------

7a9e13e Added a Paginator object based on Doctrine's paginator

Author: javiereguiluz

src/Pagination/Paginator.php

@@ -0,0 +1,110 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Pagination;
+
+use Doctrine\ORM\QueryBuilder as DoctrineQueryBuilder;
+use Doctrine\ORM\Tools\Pagination\CountWalker;
+use Doctrine\ORM\Tools\Pagination\Paginator as DoctrinePaginator;
+
+/**
+ * @author Javier Eguiluz <[email protected]>
+ */
+class Paginator
+{
+    private const PAGE_SIZE = 10;
+    private $queryBuilder;
+    private $currentPage;
+    private $pageSize;
+    private $results;
+    private $numResults;
+
+    public function __construct(DoctrineQueryBuilder $queryBuilder, int $pageSize = self::PAGE_SIZE)
+    {
+        $this->queryBuilder = $queryBuilder;
+        $this->pageSize = $pageSize;
+    }
+
+    public function paginate(int $page = 1): self
+    {
+        $this->currentPage = max(1, $page);
+        $firstResult = ($this->currentPage - 1) * $this->pageSize;
+
+        $query = $this->queryBuilder
+            ->setFirstResult($firstResult)
+            ->setMaxResults($this->pageSize)
+            ->getQuery();
+
+        if (0 === \count($this->queryBuilder->getDQLPart('join'))) {
+            $query->setHint(CountWalker::HINT_DISTINCT, false);
+        }
+
+        $paginator = new DoctrinePaginator($query, true);
+
+        $useOutputWalkers = \count($this->queryBuilder->getDQLPart('having') ?: []) > 0;
+        $paginator->setUseOutputWalkers($useOutputWalkers);
+
+        $this->results = $paginator->getIterator();
+        $this->numResults = $paginator->count();
+
+        return $this;
+    }
+
+    public function getCurrentPage(): int
+    {
+        return $this->currentPage;
+    }
+
+    public function getLastPage(): int
+    {
+        return (int) ceil($this->numResults / $this->pageSize);
+    }
+
+    public function getPageSize(): int
+    {
+        return $this->pageSize;
+    }
+
+    public function hasPreviousPage(): bool
+    {
+        return $this->currentPage > 1;
+    }
+
+    public function getPreviousPage(): int
+    {
+        return max(1, $this->currentPage - 1);
+    }
+
+    public function hasNextPage(): bool
+    {
+        return $this->currentPage < $this->getLastPage();
+    }
+
+    public function getNextPage(): int
+    {
+        return min($this->getLastPage(), $this->currentPage + 1);
+    }
+
+    public function hasToPaginate(): bool
+    {
+        return $this->numResults > $this->pageSize;
+    }
+
+    public function getNumResults(): int
+    {
+        return $this->numResults;
+    }
+
+    public function getResults(): \Traversable
+    {
+        return $this->results;
+    }
+}

src/Repository/PostRepository.php

@@ -13,10 +13,9 @@
 
 use App\Entity\Post;
 use App\Entity\Tag;
+use App\Pagination\Paginator;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
 use Doctrine\Common\Persistence\ManagerRegistry;
-use Doctrine\ORM\QueryBuilder;
-use Doctrine\ORM\Tools\Pagination\Paginator;
 
 /**
  * This custom Doctrine repository contains some methods which are useful when
@@ -35,7 +34,7 @@ public function __construct(ManagerRegistry $registry)
         parent::__construct($registry, Post::class);
     }
 
-    public function findLatest(int $page = 1, Tag $tag = null): array
+    public function findLatest(int $page = 1, Tag $tag = null): Paginator
     {
         $qb = $this->createQueryBuilder('p')
             ->addSelect('a', 't')
@@ -51,7 +50,7 @@ public function findLatest(int $page = 1, Tag $tag = null): array
                 ->setParameter('tag', $tag);
         }
 
-        return $this->createPaginator($qb, $page);
+        return (new Paginator($qb))->paginate($page);
     }
 
     /**
@@ -101,31 +100,4 @@ private function extractSearchTerms(string $searchQuery): array
             return 2 <= mb_strlen($term);
         });
     }
-
-    private function createPaginator(QueryBuilder $queryBuilder, int $currentPage, int $pageSize = Post::NUM_ITEMS)
-    {
-        $currentPage = $currentPage < 1 ? 1 : $currentPage;
-        $firstResult = ($currentPage - 1) * $pageSize;
-
-        $query = $queryBuilder
-            ->setFirstResult($firstResult)
-            ->setMaxResults($pageSize)
-            ->getQuery();
-
-        $paginator = new Paginator($query);
-        $numResults = $paginator->count();
-        $hasPreviousPage = $currentPage > 1;
-        $hasNextPage = ($currentPage * $pageSize) < $numResults;
-
-        return [
-            'results' => $paginator->getIterator(),
-            'currentPage' => $currentPage,
-            'hasPreviousPage' => $hasPreviousPage,
-            'hasNextPage' => $hasNextPage,
-            'previousPage' => $hasPreviousPage ? $currentPage - 1 : null,
-            'nextPage' => $hasNextPage ? $currentPage + 1 : null,
-            'numPages' => (int) ceil($numResults / $pageSize),
-            'haveToPaginate' => $numResults > $pageSize,
-        ];
-    }
 }

templates/blog/index.html.twig

@@ -24,7 +24,7 @@
         <div class="well">{{ 'post.no_posts_found'|trans }}</div>
     {% endfor %}
 
-    {% if paginator.haveToPaginate %}
+    {% if paginator.hasToPaginate %}
         <div class="navigation text-center">
             <ul class="pagination">
                 {% if paginator.hasPreviousPage %}
@@ -33,7 +33,7 @@
                     <li class="prev disabled"><span><i class="fa fw fa-arrow-left"></i> Previous</span></li>
                 {% endif %}
 
-                {% for i in 1..paginator.numPages %}
+                {% for i in 1..paginator.lastPage %}
                     {% if i == paginator.currentPage %}
                         <li class="active"><span>{{ i }} <span class="sr-only">(current)</span></span></li>
                     {% else %}