(feat) setup appdata folder based on config

Signed-off-by: Akhil <akhil@e.email>

Author: akhil1508

config/config.sample.php

@@ -2291,6 +2291,15 @@
 	 */
 	'updatedirectory' => '',
 
+	/**
+ 	* Override where Nextcloud stores the ``appdata_INSTANCEID`` directory. Useful
+ 	* when using remote object storage where local system disks provide faster data
+ 	* access. Defaults to `datadirectory` if unset.
+ 	*
+ 	* The Web server user must have write access to this directory.
+ 	*/
+	'appdatadirectory' => '',
+
 	/**
 	 * Block specific files or filenames, disallowing uploads or access (read and write).
 	 * ``.htaccess`` is blocked by default.

lib/private/Files/SetupManager.php

@@ -429,10 +429,26 @@ public function setupRoot(): void {
 		foreach ($rootMounts as $rootMountProvider) {
 			$this->mountManager->addMount($rootMountProvider);
 		}
-
+		$this->setupAppData();
 		$this->eventLogger->end('fs:setup:root');
 	}
 
+	private function setupAppData(): void {
+		if ($appdatadirectory = $this->config->getSystemValue('appdatadirectory', null)) {
+			$instanceId = $this->config->getSystemValue('instanceid', null);
+			if ($instanceId === null) {
+				throw new \RuntimeException('no instance id!');
+			}
+			$folderName = 'appdata_' . $instanceId;
+			$arguments = [
+				'datadir' => $appdatadirectory,
+			];
+			$storage = new \OC\Files\Storage\Local($arguments);
+			$mount = new \OC\Files\Mount\MountPoint($storage, $folderName, $arguments);
+			$this->mountManager->addMount($mount);
+		}
+	}
+
 	/**
 	 * Get the user to setup for a path or `null` if the root needs to be setup
 	 *

lib/private/SystemConfig.php

@@ -20,6 +20,7 @@ class SystemConfig {
 	protected const DEFAULT_SENSITIVE_VALUES = [
 		'instanceid' => true,
 		'datadirectory' => true,
+		'appdatadirectory' => true,
 		'dbname' => true,
 		'dbhost' => true,
 		'dbpassword' => true,