improve memory footprint for read operations by alperozturk96 · Pull Request #2102 · nextcloud/android-library

alperozturk96 · 2026-08-03T13:37:44Z

Changes

Catches OOME
Read only once remoteData.getResponses();

github-actions · 2026-08-03T13:40:29Z

SpotBugs

Category	Base	New
Bad practice	31	31
Correctness	28	28
Dodgy code	14	14
Internationalization	6	6
Malicious code vulnerability	26	26
Multithreaded correctness	7	7
Performance	7	7
Security	4	4
Total	123	123

Copilot

Pull request overview

This PR reduces repeated WebDAV response-array access and attempts to improve memory behavior when parsing folder listings (regular files, trashbin, and versions) in the legacy owncloud remote operations.

Changes:

Cache remoteData.getResponses() into a local MultiStatusResponse[] to avoid repeated calls during parsing.
Pre-size ArrayList instances based on the number of WebDAV responses to reduce resizing overhead.
Add an OutOfMemoryError catch in ReadFolderRemoteOperation to return a failure instead of crashing.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
library/src/main/java/com/owncloud/android/lib/resources/trashbin/ReadTrashbinFolderRemoteOperation.java	Cache responses array and pre-size result list while iterating trashbin entries.
library/src/main/java/com/owncloud/android/lib/resources/files/ReadFolderRemoteOperation.java	Cache responses array, pre-size list, and add an `OutOfMemoryError` catch during folder reads.
library/src/main/java/com/owncloud/android/lib/resources/files/ReadFileVersionsRemoteOperation.java	Cache responses array and pre-size versions list while iterating version entries.

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    private void readData(MultiStatus remoteData, OwnCloudClient client) {
-        folderAndFiles = new ArrayList<>();
+        MultiStatusResponse[] responses = remoteData.getResponses();
+        folderAndFiles = new ArrayList<>(responses.length);


+        } catch (OutOfMemoryError e) {
+            mFolderAndFiles = null;
+            result = new RemoteOperationResult(
+                    new Exception("Not enough memory to read the contents of " + mRemotePath, e));


    private void readData(MultiStatus remoteData, OwnCloudClient client) {
-        versions = new ArrayList<>();
+        MultiStatusResponse[] responses = remoteData.getResponses();
+        versions = new ArrayList<>(responses.length);


nextcloud-android-bot · 2026-08-03T13:56:15Z

stable22-IT test failed: https://www.kaminsky.me/nc-dev/android-library-integrationTests/2102-IT-stable22-13-53/debug/

daniele-verducci · 2026-08-14T11:07:09Z

Hey @alperozturk96 , I was able to replicate the OOM crash using the current prod library on a directory with 12k files, and can confirm that with the library from this PR the app does NOT crash.
However, I get no feedback about the issue on the phone's screen, I just see "Loading..." and after a while "No files here".

I can see in the ADB logs the correct error:

Synchronized /InstantUpload/OpenCamera/: Unexpected exception
                                                                                                    java.lang.Exception: Not enough memory to read the contents of /InstantUpload/OpenCamera/

but nothing on the screen, so I fear that to an unbeknowing user, it may seem that the directory is effectively empty (or that the content has gone lost).