From: Eric Wong <e@80x24.org>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: Junio C Hamano <gitster@pobox.com>,
Derrick Stolee <stolee@gmail.com>,
Phillip Wood <phillip.wood@dunelm.org.uk>,
git@vger.kernel.org
Subject: Re: [PATCH v2 00/19] hashmap bug/safety/ease-of-use fixes
Date: Mon, 30 Sep 2019 10:01:38 +0000 [thread overview]
Message-ID: <20190930100137.GB24511@dcvr> (raw)
In-Reply-To: <nycvar.QRO.7.76.6.1909261032520.15067@tvgsbejvaqbjf.bet>
Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
> Hi Eric,
>
> On Tue, 24 Sep 2019, Eric Wong wrote:
>
> > Patches 1-11 are largely unchanged from the original series with the
> > exception of 2, which is new and posted at:
> >
> > https://public-inbox.org/git/20190908074953.kux7zz4y7iolqko4@whir/
> >
> > 12-17 take further steps to get us away from hashmap_entry being
> > the first element, but they're also a bit ugly because __typeof__
> > isn't portable
> >
> > 18-19 finally brings me to the APIs I want to expose without
> > relying on __typeof :)
>
> I won't have time to review this patch series, but I wanted to throw out
> the idea of storing the offset in `struct hashmap`, i.e. the offset of
> the `struct hashmap_entry` in the actual entry struct?
>
> Example:
>
> struct erics_entry {
> const char *i_want_this_to_be_the_first_field;
> struct hashmap_entry e;
> [...]
> };
>
> [...]
>
> struct erics_entry *dummy = NULL;
> size_t offset = ((char *)dummy->e) - ((char *)dummy);
> [... store that offset in the hashmap and subtract it from the
> stored pointers before returning an entry...]
>
> IOW rather than assuming that it is the first field, we could allow an
> offset other than 0. I'm just not sure how to implement this elegantly,
> but it should be much easier to do this portably than the `typeof()`
> approach.
Yeah, that needs to be &dummy->e, but that's the OFFSETOF_VAR
macro in patch 18. I think it's quite elegant, but I need to
fix a clang warning for it...
next prev parent reply other threads:[~2019-09-30 10:01 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 2:43 [PATCH 00/11] hashmap: bugfixes, safety fixes, and WIP improvements Eric Wong
2019-08-26 2:43 ` [PATCH 01/11] diff: use hashmap_entry_init on moved_entry.ent Eric Wong
2019-08-27 13:31 ` Derrick Stolee
2019-08-26 2:43 ` [PATCH 02/11] packfile: use hashmap_entry in delta_base_cache_entry Eric Wong
2019-08-26 2:43 ` [PATCH 03/11] hashmap_entry_init takes "struct hashmap_entry *" Eric Wong
2019-08-27 13:35 ` Derrick Stolee
2019-08-28 15:01 ` Johannes Schindelin
2019-08-30 19:48 ` Eric Wong
2019-09-02 13:46 ` Johannes Schindelin
2019-08-26 2:43 ` [PATCH 04/11] hashmap_entry: detect improper initialization Eric Wong
2019-08-27 9:10 ` Johannes Schindelin
2019-08-27 9:49 ` Eric Wong
2019-08-27 22:16 ` Junio C Hamano
2019-08-28 15:04 ` Johannes Schindelin
2019-08-28 9:03 ` Phillip Wood
2019-08-30 19:52 ` Eric Wong
2019-09-08 7:49 ` [RFC 04/11] coccicheck: detect hashmap_entry.hash assignment Eric Wong
2019-09-09 18:15 ` Junio C Hamano
2019-08-26 2:43 ` [PATCH 05/11] hashmap_get_next takes "const struct hashmap_entry *" Eric Wong
2019-08-26 2:43 ` [PATCH 06/11] hashmap_add takes "struct " Eric Wong
2019-08-26 2:43 ` [PATCH 07/11] hashmap_get takes "const struct " Eric Wong
2019-08-26 2:43 ` [PATCH 08/11] hashmap_remove " Eric Wong
2019-08-26 2:43 ` [PATCH 09/11] hashmap_put takes "struct " Eric Wong
2019-08-26 2:43 ` [PATCH 10/11] introduce container_of macro Eric Wong
2019-08-27 14:49 ` Derrick Stolee
2019-08-28 9:11 ` Phillip Wood
2019-08-30 19:43 ` Eric Wong
2019-08-26 2:43 ` [PATCH 11/11] hashmap_get_next returns "struct hashmap_entry *" Eric Wong
2019-08-27 14:53 ` Derrick Stolee
2019-08-30 19:36 ` Eric Wong
2019-09-24 1:03 ` [PATCH v2 00/19] hashmap bug/safety/ease-of-use fixes Eric Wong
2019-09-24 1:03 ` [PATCH v2 01/19] diff: use hashmap_entry_init on moved_entry.ent Eric Wong
2019-09-24 1:03 ` [PATCH v2 02/19] coccicheck: detect hashmap_entry.hash assignment Eric Wong
2019-09-25 12:44 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 03/19] packfile: use hashmap_entry in delta_base_cache_entry Eric Wong
2019-09-24 1:03 ` [PATCH v2 04/19] hashmap_entry_init takes "struct hashmap_entry *" Eric Wong
2019-09-25 12:48 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 05/19] hashmap_get_next takes "const struct " Eric Wong
2019-09-24 1:03 ` [PATCH v2 06/19] hashmap_add takes "struct " Eric Wong
2019-09-24 1:03 ` [PATCH v2 07/19] hashmap_get takes "const struct " Eric Wong
2019-09-25 12:52 ` Derrick Stolee
2019-09-30 9:57 ` Eric Wong
2019-09-24 1:03 ` [PATCH v2 08/19] hashmap_remove " Eric Wong
2019-09-25 12:54 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 09/19] hashmap_put takes "struct " Eric Wong
2019-09-24 1:03 ` [PATCH v2 10/19] introduce container_of macro Eric Wong
2019-09-25 13:12 ` Derrick Stolee
2019-09-30 10:39 ` Eric Wong
2019-09-24 1:03 ` [PATCH v2 11/19] hashmap_get_next returns "struct hashmap_entry *" Eric Wong
2019-09-25 13:05 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 12/19] hashmap: use *_entry APIs to wrap container_of Eric Wong
2019-09-25 13:15 ` Derrick Stolee
2019-09-24 1:03 ` [PATCH v2 13/19] hashmap_get{,_from_hash} return "struct hashmap_entry *" Eric Wong
2019-09-24 1:03 ` [PATCH v2 14/19] hashmap_cmp_fn takes hashmap_entry params Eric Wong
2019-09-24 1:03 ` [PATCH v2 15/19] hashmap: use *_entry APIs for iteration Eric Wong
2019-09-24 1:03 ` [PATCH v2 16/19] hashmap: hashmap_{put,remove} return hashmap_entry * Eric Wong
2019-09-24 1:03 ` [PATCH v2 17/19] hashmap: introduce hashmap_free_entries Eric Wong
2019-09-24 1:03 ` [PATCH v2 18/19] OFFSETOF_VAR macro to simplify hashmap iterators Eric Wong
2019-09-30 16:58 ` Junio C Hamano
2019-10-04 1:18 ` Junio C Hamano
2019-10-04 2:51 ` Eric Wong
2019-10-04 3:29 ` Junio C Hamano
2019-10-04 17:26 ` Eric Wong
2019-10-06 0:04 ` Junio C Hamano
2019-09-24 1:03 ` [PATCH v2 19/19] hashmap: remove type arg from hashmap_{get,put,remove}_entry Eric Wong
2019-09-25 12:42 ` Derrick Stolee
2019-09-25 13:30 ` [PATCH v2 00/19] hashmap bug/safety/ease-of-use fixes Derrick Stolee
2019-09-26 8:39 ` Johannes Schindelin
2019-09-30 10:01 ` Eric Wong [this message]
2019-09-26 13:48 ` Phillip Wood
2019-09-29 9:22 ` Junio C Hamano
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