--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Translation\Catalogue;
+
+/**
+ * Merge operation between two catalogues as follows:
+ * all = source ∪ target = {x: x ∈ source ∨ x ∈ target}
+ * new = all ∖ source = {x: x ∈ target ∧ x ∉ source}
+ * obsolete = source ∖ all = {x: x ∈ source ∧ x ∉ source ∧ x ∉ target} = ∅
+ * Basically, the result contains messages from both catalogues.
+ *
+ * @author Jean-François Simon <contact@jfsimon.fr>
+ */
+class MergeOperation extends AbstractOperation
+{
+ /**
+ * {@inheritdoc}
+ */
+ protected function processDomain($domain)
+ {
+ $this->messages[$domain] = array(
+ 'all' => array(),
+ 'new' => array(),
+ 'obsolete' => array(),
+ );
+
+ foreach ($this->source->all($domain) as $id => $message) {
+ $this->messages[$domain]['all'][$id] = $message;
+ $this->result->add(array($id => $message), $domain);
+ if (null !== $keyMetadata = $this->source->getMetadata($id, $domain)) {
+ $this->result->setMetadata($id, $keyMetadata, $domain);
+ }
+ }
+
+ foreach ($this->target->all($domain) as $id => $message) {
+ if (!$this->source->has($id, $domain)) {
+ $this->messages[$domain]['all'][$id] = $message;
+ $this->messages[$domain]['new'][$id] = $message;
+ $this->result->add(array($id => $message), $domain);
+ if (null !== $keyMetadata = $this->target->getMetadata($id, $domain)) {
+ $this->result->setMetadata($id, $keyMetadata, $domain);
+ }
+ }
+ }
+ }
+}