refactor(dav): improve readability of PropFindPlugin

- Minor docblock imporvements
- Extract mount path calculation to dedicated method

Signed-off-by: Josh <[email protected]>

lib/DAV/PropFindPlugin.php

@@ -16,13 +16,21 @@
 use Sabre\DAV\Server;
 use Sabre\DAV\ServerPlugin;
 
+/**
+ * SabreDAV plugin that adds group folder metadata to PROPFIND responses.
+ *
+ * Adds the mount point and group folder ID as custom WebDAV properties for group folder nodes.
+ */
 class PropFindPlugin extends ServerPlugin {
 	private ?Folder $userFolder = null;
 
 	public const MOUNT_POINT_PROPERTYNAME = '{http://nextcloud.org/ns}mount-point';
 	public const GROUP_FOLDER_ID_PROPERTYNAME = '{http://nextcloud.org/ns}group-folder-id';
 
-	public function __construct(IRootFolder $rootFolder, IUserSession $userSession) {
+	public function __construct(
+		IRootFolder $rootFolder,
+		IUserSession $userSession
+	) {
 		$user = $userSession->getUser();
 		if ($user === null) {
 			return;
@@ -41,20 +49,30 @@ public function initialize(Server $server): void {
 	}
 
 	public function propFind(PropFind $propFind, INode $node): void {
-		if ($this->userFolder === null) {
+		if (!($node instanceof GroupFolderNode) || $this->userFolder === null) {
 			return;
 		}
 
-		if ($node instanceof GroupFolderNode) {
-			$propFind->handle(
-				self::MOUNT_POINT_PROPERTYNAME,
-				/** @psalm-suppress PossiblyNullReference Null already checked above */
-				fn () => $this->userFolder->getRelativePath($node->getFileInfo()->getMountPoint()->getMountPoint())
-			);
-			$propFind->handle(
-				self::GROUP_FOLDER_ID_PROPERTYNAME,
-				fn (): int => $node->getFolderId()
-			);
-		}
+		$propFind->handle(
+			self::MOUNT_POINT_PROPERTYNAME,
+			fn() => $this->getRelativeMountPointPath($node)
+		);
+		$propFind->handle(
+			self::GROUP_FOLDER_ID_PROPERTYNAME,
+			fn (): int => $node->getFolderId()
+		);
+	}
+
+	/**
+	 * Compute the path of the mount point relative to the root of the current user's folder.
+	 *
+	 * TODO: This may be a candidate for a utility function in GF or API addition in core.
+	 */
+	private function getRelativeMountPointPath(GroupFolderNode $node): ?string {
+		// TODO: Seems there could be some more defensive null/error handling here (perhaps throwing a 404/not found + logging)
+		$fileInfo = $node->getFileInfo();
+		$mount = $fileInfo->getMountPoint();
+		$mountPointPath = $mount->getMountPoint();
+		return $this->userFolder->getRelativePath($mountPointPath);
 	}
 }