allow keeping multiple preview "versions" of the same file

The main use case here is storage provided versioning where we dont have
separate file ids for all the versions, by allowing a prefix for the
version we can store separate previews for all the versions.

Additionally, by keeping all the version previews in the same folder as the
"normal" previews they will be cleaned up properly when the file is deleted

Signed-off-by: Robin Appelman <robin@icewind.nl>

1 files changed, 39 insertions, 0 deletions

diff --git a/lib/public/Preview/IVersionedPreviewFile.php b/lib/public/Preview/IVersionedPreviewFile.php
new file mode 100644
index 00000000000..e4da914da02
--- /dev/null
+++ b/lib/public/Preview/IVersionedPreviewFile.php
@@ -0,0 +1,39 @@
+<?php declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019 Robin Appelman <robin@icewind.nl>
+ *
+ * @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/>.
+ *
+ */
+
+namespace OCP\Preview;
+
+/**
+ * Marks files that should keep multiple preview "versions" for the same file id
+ *
+ * Examples of this are files where the storage backend provides versioning, for those
+ * files, we dont have fileids for the different versions but still need to be able to generate
+ * previews for all versions
+ *
+ * @since 17.0.0
+ */
+interface IVersionedPreviewFile {
+	/**
+	 * @return string
+	 * @since 17.0.0
+	 */
+	public function getPreviewVersion(): string;
+}