owncloud/core

Enhancement: Introduce new state to prevent scanning of shallow scanned folders

Folders can be partially scanned, this means that a folder could have its closest
contents scanned (the first level), but not deeper contents. Folder "/A" could be
scanned but not "/A/B/C".

Previously, we couldn't detect that a folder had been partially scanned, so we
triggered another scan on that folder even though we already had data in the DB.

Now, we can detect that the folder has been partially scanned to avoid another
scan if it isn't needed. This leads to notable performance improvements in cases
where a FS hasn't been scanned fully. Note that an initial scan is still required,
and the performance will remain the same in this case.

https://github.com/owncloud/core/pull/38804