Re: [PATCH 0/5] Store submodules in a hash, not a linked list

> I have mentioned this patch series on the mailing list a couple of
> time [1,2] but haven't submitted it before. I just rebased it to
> current master. It is available from my Git fork [3] as branch
> "submodule-hash".
>
> The first point of this patch series is to optimize submodule
> `ref_store` lookup by storing the `ref_store`s in a hashmap rather
> than a linked list. But a more interesting second point is to weaken
> the 1:1 relationship between submodules and `ref_stores` a little bit
> more.
>
> A `files_ref_store` would be perfectly happy to represent, say, the
> references *physically* stored in a linked worktree (e.g., `HEAD`,
> `refs/bisect/*`, etc) even though that is not the complete collection
> of refs that are *logically* visible from that worktree (which
> includes references from the main repository, too). But the old code
> was confusing the two things by storing "submodule" in every
> `ref_store` instance.
>
> So push the submodule attribute down to the `files_ref_store` class
> (but continue to let the `ref_store`s be looked up by submodule).
>
> The last commit is relatively orthogonal to the others; it simplifies
> read_loose_refs() by calling resolve_ref_recursively() directly using
> the `ref_store` instance that it already has in hand, rather than
> indirectly via the public wrappers.
>
> Michael
>
> [1] http://public-inbox.org/git/341999fc-4496-b974-c117-c18a2fca1358@alum.mit.edu/
> [2] http://public-inbox.org/git/37fe2024-0378-a974-a28d-18a89d3e2312@alum.mit.edu/
> [3] https://github.com/mhagger/git
>
> Michael Haggerty (5):
>   refs: store submodule ref stores in a hashmap
>   refs: push the submodule attribute down
>   register_ref_store(): new function
>   files_ref_store::submodule: use NULL for the main repository
>   read_loose_refs(): read refs using resolve_ref_recursively()