Actualización

vendor/sonata-project/exporter/src/Source/ChainSourceIterator.php

@@ -0,0 +1,96 @@
+<?php
+
+/*
+ * This file is part of the Sonata Project package.
+ *
+ * (c) Thomas Rabaix <thomas.rabaix@sonata-project.org>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Sonata\Exporter\Source;
+
+use ArrayIterator;
+
+class ChainSourceIterator implements SourceIteratorInterface
+{
+    /**
+     * @var ArrayIterator
+     */
+    protected $sources;
+
+    /**
+     * @param array $sources
+     */
+    public function __construct(array $sources = [])
+    {
+        $this->sources = new ArrayIterator();
+
+        foreach ($sources as $source) {
+            $this->addSource($source);
+        }
+    }
+
+    /**
+     * @param SourceIteratorInterface $source
+     */
+    public function addSource(SourceIteratorInterface $source)
+    {
+        $this->sources->append($source);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function current()
+    {
+        return $this->sources->current()->current();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function next()
+    {
+        $this->sources->current()->next();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function key()
+    {
+        return $this->sources->current()->key();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function valid()
+    {
+        while (!$this->sources->current()->valid()) {
+            $this->sources->next();
+
+            if (!$this->sources->valid()) {
+                return false;
+            }
+
+            $this->sources->current()->rewind();
+        }
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function rewind()
+    {
+        if ($this->sources->current()) {
+            $this->sources->current()->rewind();
+        }
+    }
+}
+
+class_exists(\Exporter\Source\ChainSourceIterator::class);