Lazy adapters implementation

Author: Koc

src/Pagerfanta/Adapter/ElasticaAdapter.php

@@ -14,7 +14,7 @@
 use Elastica\Query;
 use Elastica\SearchableInterface;
 
-class ElasticaAdapter implements AdapterInterface
+class ElasticaAdapter implements LazyAdapterInterface
 {
     /**
      * @var Query

src/Pagerfanta/Adapter/LazyAdapterInterface.php

@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the Pagerfanta package.
+ *
+ * (c) Pablo Díez <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Pagerfanta\Adapter;
+
+/**
+ * LazyAdapterInterface that marks adapter lazy.
+ *
+ * @author Konstantin Myakshin <[email protected]>
+ */
+interface LazyAdapterInterface extends AdapterInterface
+{
+
+}

src/Pagerfanta/Pagerfanta.php

@@ -12,6 +12,7 @@
 namespace Pagerfanta;
 
 use Pagerfanta\Adapter\AdapterInterface;
+use Pagerfanta\Adapter\LazyAdapterInterface;
 use Pagerfanta\Exception\LogicException;
 use Pagerfanta\Exception\NotBooleanException;
 use Pagerfanta\Exception\NotIntegerMaxPerPageException;
@@ -225,7 +226,9 @@ private function filterCurrentPage($currentPage)
     {
         $currentPage = $this->toInteger($currentPage);
         $this->checkCurrentPage($currentPage);
-        $currentPage = $this->filterOutOfRangeCurrentPage($currentPage);
+        if (!$this->adapter instanceof LazyAdapterInterface) {
+            $currentPage = $this->filterOutOfRangeCurrentPage($currentPage);
+        }
 
         return $currentPage;
     }
@@ -316,7 +319,18 @@ private function getCurrentPageResultsFromAdapter()
         $offset = $this->calculateOffsetForCurrentPageResults();
         $length = $this->getMaxPerPage();
 
-        return $this->adapter->getSlice($offset, $length);
+        $slice = $this->adapter->getSlice($offset, $length);
+
+        if ($this->adapter instanceof LazyAdapterInterface) {
+            $page = $this->filterOutOfRangeCurrentPage($this->getCurrentPage());
+            if ($page != $this->getCurrentPage()) {
+                $this->setCurrentPage($page);
+
+                return $this->getCurrentPageResultsFromAdapter();
+            }
+        }
+
+        return $slice;
     }
 
     private function calculateOffsetForCurrentPageResults()