due to internal implementations touch will always be successful - $mtime will be stored in the cache
from desktop client perspective it is necessary to set the mtime under every condition

The user id has to be returned.

updating a existing large file creates new file chunks. Therefore createFile() needs to check not only if we can write to the parent folder but also if we can update the existing file"

If a existing file in Shared/ with update permissions gets updated we need to write the .part file to a different place because we can't create new files in the Shared folder

And is when using index.php as entry point

In my test here 1 SELECT instead of 5 (when doing a DAV request,
probably similar for other requests)

It doesn't make sense for subclasses to have to implement
all methods.

correctly expire cache if version file changed. Fixes problem that ownCloud only starts upgrading during login

e.g. LOCK would break with this approach