allow setting offset for queries not limited to the users home storage

multi-storage offset is cheap (enough) now

Signed-off-by: Robin Appelman <[email protected]>

apps/dav/lib/Files/FileSearchBackend.php

@@ -275,7 +275,7 @@ private function transformQuery(Query $query): ISearchQuery {
 		// TODO offset
 		$limit = $query->limit;
 		$orders = array_map([$this, 'mapSearchOrder'], $query->orderBy);
-		$offset = 0;
+		$offset = $limit->firstResult;
 
 		$limitHome = false;
 		$ownerProp = $this->extractWhereValue($query->where, FilesPlugin::OWNER_ID_PROPERTYNAME, Operator::OPERATION_EQUAL);
@@ -285,7 +285,6 @@ private function transformQuery(Query $query): ISearchQuery {
 			} else {
 				throw new \InvalidArgumentException("Invalid search value for '{http://owncloud.org/ns}owner-id', only the current user id is allowed");
 			}
-			$offset = $limit->firstResult;
 		}
 
 		return new SearchQuery(