[Yum-devel] Background downloading

[Zdeněk Pavlas]

Hi,

Another try at downloading without the /var/run/yum.pid lock.

1) To be safe, it works only when --downloadonly, so we don't
have to reopen databases.

2) Download packages to private tmpdir, then acquire the lock,
and move files to their original place.

3) It's quite difficult to avoid predownload_hook to be called
in "unlocked" state.  I move repo cachedirs to new tmpdir to
make this safe.  This is probably one more reason to finally
integrate presto.