1 files changed, 54 insertions, 0 deletions
diff --git a/lib/private/Files/ObjectStore/Mapper.php b/lib/private/Files/ObjectStore/Mapper.php
new file mode 100644
index 00000000000..e1174a285a6
--- /dev/null
+++ b/lib/private/Files/ObjectStore/Mapper.php
@@ -0,0 +1,54 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OC\Files\ObjectStore;
+
+use OCP\IConfig;
+use OCP\IUser;
+
+/**
+ * Class Mapper
+ *
+ * @package OC\Files\ObjectStore
+ *
+ * Map a user to a bucket.
+ */
+class Mapper {
+	/** @var IUser */
+	private $user;
+
+	/** @var IConfig */
+	private $config;
+
+	/**
+	 * Mapper constructor.
+	 *
+	 * @param IUser $user
+	 * @param IConfig $config
+	 */
+	public function __construct(IUser $user, IConfig $config) {
+		$this->user = $user;
+		$this->config = $config;
+	}
+
+	/**
+	 * @param int $numBuckets
+	 * @return string
+	 */
+	public function getBucket($numBuckets = 64) {
+		// Get the bucket config and shift if provided.
+		// Allow us to prevent writing in old filled buckets
+		$config = $this->config->getSystemValue('objectstore_multibucket');
+		$minBucket = is_array($config) && isset($config['arguments']['min_bucket'])
+			? (int)$config['arguments']['min_bucket']
+			: 0;
+
+		$hash = md5($this->user->getUID());
+		$num = hexdec(substr($hash, 0, 4));
+		return (string)(($num % ($numBuckets - $minBucket)) + $minBucket);
+	}
+}