Move to dedicated file attachment service

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/Service/ICustomAttachmentService.php

@@ -0,0 +1,42 @@
+<?php
+/*
+ * @copyright Copyright (c) 2020 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+declare(strict_types=1);
+
+
+namespace OCA\Deck\Service;
+
+
+/**
+ * Interface to implement in case attachments are handled by a different backend than
+ * then oc_deck_attachments table, e.g. for file sharing. When this interface is used
+ * for implementing an attachment handler no backlink will be stored in the deck attachments
+ * table and it is up to the implementation to track attachment to card relation.
+ */
+interface ICustomAttachmentService {
+
+	public function listAttachments(int $cardId): array;
+
+	public function getAttachmentCount(int $cardId): int;
+
+}