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From: Junio C Hamano <gitster@pobox.com>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>,
	David Turner <novalis@novalis.org>, Jeff King <peff@peff.net>,
	git@vger.kernel.org
Subject: Re: [PATCH 00/20] Separate `ref_cache` into a separate module
Date: Mon, 20 Mar 2017 10:25:37 -0700
Message-ID: <xmqqo9wvx3la.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <cover.1490026594.git.mhagger@alum.mit.edu>

Michael Haggerty <mhagger@alum.mit.edu> writes:

> * (And the main goal): Avoid reading and parsing the *whole
>   `packed-refs` file* (as we do now) every time any part of it is
>   needed. Instead, use binary search to find the reference and/or
>   range of references that we want, and parse the info out of the
>   mmapped image on the fly.

Oooohh....  Juicy.

> This patch series extracts a `ref_cache` module out of
> `files_ref_cache`, and goes some way to disentangling those two
> modules, which until now were overly intimate with each other:
>
> * Remove `verify_refname_available()` from the refs VTABLE, instead
>   implementing it in a generic way that uses only the usual refs API
>   to talk to the `ref_store`.
>
> * Split `ref_cache`-related code into a new module,
>   `refs/ref-cache.{c,h}`. Encapsulate the data structure in a new
>   class, `struct ref_cache`.
>
> * Change the lazy-filling mechanism of `ref_cache` to call back to its
>   backing `ref_store` via a callback function rather than calling
>   `read_loose_refs()` directly.

Nice.

> * Move the special handling of `refs/bisect/` from `ref_cache` to
>   `files_ref_store`.
>
> * Make `cache_ref_iterator_begin()` smarter, and change external users
>   to iterate via this interface instead of using
>   `do_for_each_entry_in_dir()`.
>
> Even after this patch series, the modules are still too intimate for
> my taste, but I think this is a big step forward, and it is enough to
> allow the other changes that I've been working on.
>
> These patches depend on Duy's nd/files-backend-git-dir branch, v6 [2].
> They are also available from my GitHub fork [1] as branch
> `separate-ref-cache`.
>
> Happily, this patch series actually removes a few more lines than it
> adds, mostly thanks to the simpler `verify_refname_available()`
> implementation.

Thanks.

  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-20 16:33 Michael Haggerty
2017-03-20 16:33 ` [PATCH 01/20] get_ref_dir(): don't call read_loose_refs() for "refs/bisect" Michael Haggerty
2017-03-20 16:33 ` [PATCH 02/20] refs_read_raw_ref(): new function Michael Haggerty
2017-03-20 16:33 ` [PATCH 03/20] refs_ref_iterator_begin(): " Michael Haggerty
2017-03-20 16:33 ` [PATCH 04/20] refs_verify_refname_available(): implement once for all backends Michael Haggerty
2017-03-20 17:42   ` Jeff King
2017-03-20 22:20     ` Michael Haggerty
2017-03-20 16:33 ` [PATCH 05/20] refs_verify_refname_available(): use function in more places Michael Haggerty
2017-03-20 16:33 ` [PATCH 06/20] Rename `add_ref()` to `add_ref_entry()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 07/20] Rename `find_ref()` to `find_ref_entry()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 08/20] Rename `remove_entry()` to `remove_entry_from_dir()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 09/20] refs: split `ref_cache` code into separate files Michael Haggerty
2017-03-20 17:49   ` Jeff King
2017-03-20 19:47     ` Junio C Hamano
2017-03-20 20:35       ` Stefan Beller
2017-03-20 22:40         ` Junio C Hamano
2017-03-20 16:33 ` [PATCH 10/20] ref-cache: introduce a new type, ref_cache Michael Haggerty
2017-03-20 16:33 ` [PATCH 11/20] refs: record the ref_store in ref_cache, not ref_dir Michael Haggerty
2017-03-20 17:51   ` Jeff King
2017-03-20 22:39     ` Michael Haggerty
2017-03-20 16:33 ` [PATCH 12/20] ref-cache: use a callback function to fill the cache Michael Haggerty
2017-03-20 16:33 ` [PATCH 13/20] refs: handle "refs/bisect/" in `loose_fill_ref_dir()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 14/20] do_for_each_entry_in_dir(): eliminate `offset` argument Michael Haggerty
2017-03-20 16:33 ` [PATCH 15/20] get_loose_ref_dir(): function renamed from get_loose_refs() Michael Haggerty
2017-03-20 16:33 ` [PATCH 16/20] get_loose_ref_cache(): new function Michael Haggerty
2017-03-20 16:33 ` [PATCH 17/20] cache_ref_iterator_begin(): make function smarter Michael Haggerty
2017-03-20 16:33 ` [PATCH 18/20] commit_packed_refs(): use reference iteration Michael Haggerty
2017-03-20 18:05   ` Jeff King
2017-03-22  8:42     ` Michael Haggerty
2017-03-22 13:06       ` Jeff King
2017-03-20 16:33 ` [PATCH 19/20] files_pack_refs(): " Michael Haggerty
2017-03-20 16:33 ` [PATCH 20/20] do_for_each_entry_in_dir(): delete function Michael Haggerty
2017-03-20 17:25 ` Junio C Hamano [this message]
2017-03-20 18:12 ` [PATCH 00/20] Separate `ref_cache` into a separate module Jeff King
2017-03-20 18:24 ` Ævar Arnfjörð Bjarmason
2017-03-20 18:30   ` Jeff King
2017-03-20 22:32 ` Junio C Hamano
2017-03-20 22:48   ` Michael Haggerty

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