Re: [RFC/WIP PATCH] object store classification

[Junio C Hamano <gitster@pobox.com>]

Stefan Beller <sbeller@google.com> writes:

>> At the implementation level, it should have a
>> hashtable (lazily populated) for all the objects in a single
>> $GIT_OBJECT_DIRECTORY, grafts/replace info, and a set of pointers to
>> other object-store instances that are its alternate object stores.
>
> So one repository has one or more object stores?

One repository foo/.git/ has one foo/.git/objects/ directory, so it
has its own single object store.  That object store may refer to
another object store by having foo/.git/objects/info/alternates.

Similarly, foo/.git/objects/info/grafts and foo/.git/refs/replace/
would belong to the single object store repository foo/.git/ has.

> I would expect that most of the time the question from above
> "give me info on the object I can refer to with this object name"
> is asked with the additional information: "and I know it is in this
> repository", so we rather want to have
>
>   lookup_object(struct *repo, char *name);
>
> instead of
>
>   lookup_object(struct *object_store, char *name);

Absolutely.  That is why repository has its own single object_store,
which may refer to other object_stores.