Reset stuck chunked uploads eventually #5344 (#5443)

Previously this wasn't happening for errors that were not
NormalErrors because they don't end up in the blacklist.

This revises the resetting logic to be independent of the
error blacklist and make use of UploadInfo::errorCount
instead.

412 errors should reset chunked uploads because they might be
indicative of a checksum error.

Additionally, server bugs might require that additional
errors cause an upload reset. To allow that, a new capability
is added that can be used to advise the client about this.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/libsync/capabilities.h b/src/libsync/capabilities.h
index 76e2b6f22..e3d8c013c 100644
--- a/src/libsync/capabilities.h
+++ b/src/libsync/capabilities.h
@@ -81,6 +81,25 @@ public:
      */
     QByteArray uploadChecksumType() const;
 
+    /**
+     * List of HTTP error codes should be guaranteed to eventually reset
+     * failing chunked uploads.
+     *
+     * The resetting works by tracking UploadInfo::errorCount.
+     *
+     * Note that other error codes than the ones listed here may reset the
+     * upload as well.
+     *
+     * Motivation: See #5344. They should always be reset on 412 (possibly
+     * checksum error), but broken servers may also require resets on
+     * unusual error codes such as 503.
+     *
+     * Path: dav/httpErrorCodesThatResetFailingChunkedUploads
+     * Default: []
+     * Example: [503, 500]
+     */
+    QList<int> httpErrorCodesThatResetFailingChunkedUploads() const;
+
 private:
     QVariantMap _capabilities;
 };