Re: [PATCH v3 00/15] packfile: carve out a new packfile store

> Hi,
>
> information about a object database's packfiles is currently distributed
> across two different structures:
>
>   - `struct packed_git` contains the `next` pointer as well as the
>     `mru_head`, both of which serve to store the list of packfiles.
>
>   - `struct object_database` contains several fields that relate to the
>     packfiles.
>
> So we don't really have a central data structure that tracks our
> packfiles, and consequently responsibilities aren't always clear cut.
> A consequence for the upcoming pluggable object databases is that this
> makes it very hard to move management of packfiles from the object
> database level down into the object database source.
>
> This patch series introduces a new `struct packfile_store`, which is
> about to become the single source of truth for managing packfiles, and
> carves out the packfile store subsystem.
>
> This is the first step to make packfiles work with pluggable object
> databases. Next steps will be to:
>
>   - Move the `struct packed_git::next` and `struct packed::mru_head`
>     pointers into the packfile store so that `struct packed_git` only
>     tracks a single packfile.
>
>   - Push the `struct packfile_store` down one level so that it's not
>     hosted by the object database anymore, but instead by the object
>     database source.
>