rpm-ostree currently uses ostree_repo_checkout_tree(), which as a side
effect will use the uncompressed objects cache by default. This is
rather annoying if you're using rpm-ostree on a server-side
repository, because if you then rsync the repo, you'll be syncing out
the uncompressed objects unless you exclude them.
We added the ability to disable the uncompressed cache in the
repository config to fix this, but it's better to allow application
control over this. The uncompressed cache will in some future version
become opt in as well.
This new API further:
- Drops the `GFile` usage in favor of `openat` APIs
- Improves ergonomics by avoiding callers having to query the source
`GFileInfo` (and carry around a copy of `OSTREE_GIO_FAST_QUERYINFO`)
- Has a more extensible options structure
Per the comment, I rather crudely have the `ostree checkout` builtin
call both APIs to ensure some testing coverage.
However, I'd like to in the future have easier-to-set-up testing code
that calls `libtest.sh` to set up dummy data.
We already set all file mtimes to 0 so that they are constant
over all checkouts, and can be made constant with a known value from
the system where the ostree was created.
However, this was not happening for directories. Zero their mtimes too.
This is important for shipping a fontconfig cache in the ostree;
the fontconfig cache files embed a directory mtime.