From: Derrick Stolee <stolee@gmail.com>
To: "René Scharfe" <l.s.r@web.de>,
"Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>,
git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>,
Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH 15/16] commit-reach: make can_all_from_reach... linear
Date: Fri, 5 Oct 2018 08:15:09 -0400 [thread overview]
Message-ID: <f27fd384-6cfa-5acb-3e2b-72668f04d689@gmail.com> (raw)
In-Reply-To: <7b95417a-c8fb-4f1e-cb09-c36804a3a4d0@web.de>
On 10/4/2018 6:59 PM, René Scharfe wrote:
> Am 01.10.2018 um 22:37 schrieb René Scharfe:
>> Am 01.10.2018 um 21:26 schrieb Derrick Stolee:
>>> Good catch! I'm disappointed that we couldn't use type-checking here, as
>>> it is quite difficult to discover that the types are wrong here.
>> Generics in C are hard, and type checking traditionally falls by the
>> wayside. You could use macros for that, like klib [*] does, but that
>> has its own downsides (more object text, debugging the sort macros
>> themselves is harder).
>>
>> [*] https://github.com/attractivechaos/klib/blob/master/ksort.h
> We could also do something like this to reduce the amount of manual
> casting, but do we want to? (Macro at the bottom, three semi-random
> examples at the top.)
I like the idea! It certainly can assist in some of the repeat work when
preparing to QSORT, and make it less error-prone.
> ---
> bisect.c | 11 +++--------
> commit-graph.c | 9 ++-------
> commit-reach.c | 12 +++++-------
> git-compat-util.h | 12 ++++++++++++
> 4 files changed, 22 insertions(+), 22 deletions(-)
>
> diff --git a/bisect.c b/bisect.c
> index e8b17cf7e1..06be3a3c15 100644
> --- a/bisect.c
> +++ b/bisect.c
> @@ -192,16 +192,11 @@ struct commit_dist {
> int distance;
> };
>
> -static int compare_commit_dist(const void *a_, const void *b_)
> -{
> - struct commit_dist *a, *b;
> -
> - a = (struct commit_dist *)a_;
> - b = (struct commit_dist *)b_;
> +DEFINE_SORT(sort_by_commit_dist, struct commit_dist, a, b, {
> if (a->distance != b->distance)
> return b->distance - a->distance; /* desc sort */
> return oidcmp(&a->commit->object.oid, &b->commit->object.oid);
> -}
> +})
>
> static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
> {
> @@ -223,7 +218,7 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
> array[cnt].distance = distance;
> cnt++;
> }
> - QSORT(array, cnt, compare_commit_dist);
> + sort_by_commit_dist(array, cnt);
> for (p = list, i = 0; i < cnt; i++) {
> struct object *obj = &(array[i].commit->object);
>
> diff --git a/commit-graph.c b/commit-graph.c
> index 7f4519ec3b..a2202414e0 100644
> --- a/commit-graph.c
> +++ b/commit-graph.c
> @@ -550,12 +550,7 @@ static void write_graph_chunk_large_edges(struct hashfile *f,
> }
> }
>
> -static int commit_compare(const void *_a, const void *_b)
> -{
> - const struct object_id *a = (const struct object_id *)_a;
> - const struct object_id *b = (const struct object_id *)_b;
> - return oidcmp(a, b);
> -}
> +DEFINE_SORT(sort_oids, struct object_id, a, b, return oidcmp(a, b))
>
> struct packed_commit_list {
> struct commit **list;
> @@ -780,7 +775,7 @@ void write_commit_graph(const char *obj_dir,
>
> close_reachable(&oids);
>
> - QSORT(oids.list, oids.nr, commit_compare);
> + sort_oids(oids.list, oids.nr);
>
> count_distinct = 1;
> for (i = 1; i < oids.nr; i++) {
> diff --git a/commit-reach.c b/commit-reach.c
> index 2f5e592d16..3aef47c3dd 100644
> --- a/commit-reach.c
> +++ b/commit-reach.c
> @@ -527,17 +527,15 @@ int commit_contains(struct ref_filter *filter, struct commit *commit,
> return is_descendant_of(commit, list);
> }
>
> -static int compare_commits_by_gen(const void *_a, const void *_b)
> -{
> - const struct commit *a = *(const struct commit * const *)_a;
> - const struct commit *b = *(const struct commit * const *)_b;
> -
> +DEFINE_SORT(sort_commits_by_gen, struct commit *, ap, bp, {
> + const struct commit *a = *ap;
> + const struct commit *b = *bp;
> if (a->generation < b->generation)
> return -1;
> if (a->generation > b->generation)
> return 1;
> return 0;
> -}
> +})
Here, to make the macro version compile you need to cast ap and bp,
which gives us a level of type-safety that wasn't there before. That can
help us find errors at compile-time!
>
> int can_all_from_reach_with_flag(struct object_array *from,
> unsigned int with_flag,
> @@ -580,7 +578,7 @@ int can_all_from_reach_with_flag(struct object_array *from,
> nr_commits++;
> }
>
> - QSORT(list, nr_commits, compare_commits_by_gen);
> + sort_commits_by_gen(list, nr_commits);
>
> for (i = 0; i < nr_commits; i++) {
> /* DFS from list[i] */
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 5f2e90932f..f9e78d69a2 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -1066,6 +1066,18 @@ static inline void sane_qsort(void *base, size_t nmemb, size_t size,
> qsort(base, nmemb, size, compar);
> }
>
> +#define DEFINE_SORT(name, elemtype, one, two, code) \
> +static int name##_compare(const void *one##_v_, const void *two##_v_) \
> +{ \
> + elemtype const *one = one##_v_; \
> + elemtype const *two = two##_v_; \
> + code; \
> +} \
> +static void name(elemtype *array, size_t n) \
> +{ \
> + QSORT(array, n, name##_compare); \
> +}
> +
I would use this macro.
Thanks,
-Stolee
next prev parent reply other threads:[~2018-10-05 12:15 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 13:00 [PATCH 00/16] Consolidate reachability logic Derrick Stolee via GitGitGadget
2018-06-19 20:25 ` [PATCH 04/16] upload-pack: make reachable() more generic Derrick Stolee via GitGitGadget
2018-06-19 20:35 ` [PATCH 05/16] upload-pack: refactor ok_to_give_up() Derrick Stolee via GitGitGadget
2018-06-25 17:16 ` [PATCH 01/16] commit-reach: move walk methods from commit.c Derrick Stolee via GitGitGadget
2018-07-16 18:57 ` Stefan Beller
2018-07-16 21:31 ` Jonathan Tan
2018-06-25 17:35 ` [PATCH 02/16] commit-reach: move ref_newer from remote.c Derrick Stolee via GitGitGadget
2018-07-16 19:10 ` Stefan Beller
2018-06-25 18:01 ` [PATCH 03/16] commit-reach: move commit_contains from ref-filter Derrick Stolee via GitGitGadget
2018-07-16 19:14 ` Stefan Beller
2018-06-28 12:31 ` [PATCH 15/16] commit-reach: make can_all_from_reach... linear Derrick Stolee via GitGitGadget
2018-07-16 22:37 ` Stefan Beller
2018-07-17 1:16 ` Jonathan Tan
2018-10-01 19:16 ` René Scharfe
2018-10-01 19:26 ` Derrick Stolee
2018-10-01 20:37 ` René Scharfe
2018-10-04 22:59 ` René Scharfe
2018-10-05 12:15 ` Derrick Stolee [this message]
2018-10-05 16:51 ` Jeff King
2018-10-05 18:48 ` René Scharfe
2018-10-05 19:08 ` Jeff King
2018-10-05 19:36 ` René Scharfe
2018-10-05 19:42 ` Jeff King
2018-10-14 14:29 ` René Scharfe
2018-10-15 15:31 ` Derrick Stolee
2018-10-15 16:26 ` René Scharfe
2018-10-16 23:09 ` Junio C Hamano
2018-10-17 8:33 ` Jeff King
2020-11-18 2:16 ` Jonathan Nieder
2020-11-18 6:54 ` Jeff King
2020-11-18 17:47 ` René Scharfe
2018-10-05 19:12 ` Ævar Arnfjörð Bjarmason
2018-10-05 19:28 ` Jeff King
2018-10-05 19:42 ` Ævar Arnfjörð Bjarmason
2018-10-05 19:44 ` Jeff King
2018-07-12 20:47 ` [PATCH 06/16] upload-pack: generalize commit date cutoff Derrick Stolee via GitGitGadget
2018-07-16 19:38 ` Stefan Beller
2018-07-18 16:04 ` Derrick Stolee
2018-07-12 20:52 ` [PATCH 07/16] commit-reach: move can_all_from_reach_with_flags Derrick Stolee via GitGitGadget
2018-07-16 22:37 ` Jonathan Tan
2018-07-13 14:06 ` [PATCH 08/16] test-reach: create new test tool for ref_newer Derrick Stolee via GitGitGadget
2018-07-16 23:00 ` Jonathan Tan
2018-07-18 16:14 ` Derrick Stolee
2018-07-13 14:28 ` [PATCH 09/16] test-reach: test in_merge_bases Derrick Stolee via GitGitGadget
2018-07-13 14:38 ` [PATCH 10/16] test-reach: test is_descendant_of Derrick Stolee via GitGitGadget
2018-07-13 14:51 ` [PATCH 11/16] test-reach: test get_merge_bases_many Derrick Stolee via GitGitGadget
2018-07-16 21:24 ` Stefan Beller
2018-07-16 23:08 ` Jonathan Tan
2018-07-13 16:51 ` [PATCH 12/16] test-reach: test reduce_heads Derrick Stolee via GitGitGadget
2018-07-16 21:30 ` Stefan Beller
2018-07-16 21:59 ` Eric Sunshine
2018-07-13 17:22 ` [PATCH 13/16] test-reach: test can_all_from_reach_with_flags Derrick Stolee via GitGitGadget
2018-07-16 21:54 ` Stefan Beller
2018-07-18 16:54 ` Derrick Stolee
2018-07-17 0:10 ` Jonathan Tan
2018-07-13 18:37 ` [PATCH 14/16] commit-reach: replace ref_newer logic Derrick Stolee via GitGitGadget
2018-07-16 22:16 ` Stefan Beller
2018-07-13 19:25 ` [PATCH 16/16] commit-reach: use can_all_from_reach Derrick Stolee via GitGitGadget
2018-07-16 22:47 ` Stefan Beller
2018-07-16 13:54 ` [PATCH 00/16] Consolidate reachability logic Ramsay Jones
2018-07-16 16:18 ` Jeff King
2018-07-16 18:40 ` Eric Sunshine
2018-07-16 18:56 ` Jeff King
2018-07-16 18:59 ` Eric Sunshine
2018-07-18 12:32 ` Johannes Schindelin
2018-07-18 12:23 ` Johannes Schindelin
2018-07-18 19:21 ` Jeff King
2018-07-19 16:34 ` Johannes Schindelin
2018-07-16 17:26 ` Stefan Beller
2018-07-16 18:44 ` Eric Sunshine
2018-07-16 18:47 ` Derrick Stolee
2018-07-18 12:28 ` Johannes Schindelin
2018-07-18 15:01 ` Duy Nguyen
2018-07-18 17:01 ` Junio C Hamano
2018-07-18 17:11 ` Derrick Stolee
2018-07-19 16:37 ` Johannes Schindelin
2018-07-19 16:32 ` Johannes Schindelin
2018-07-20 16:33 ` [PATCH v2 00/18] " Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 01/18] commit-reach: move walk methods from commit.c Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 02/18] commit.h: remove method declarations Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 03/18] commit-reach: move ref_newer from remote.c Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 04/18] commit-reach: move commit_contains from ref-filter Derrick Stolee
2018-08-28 21:24 ` Jonathan Nieder
2018-08-28 21:33 ` Derrick Stolee
2018-08-28 21:36 ` [PATCH] commit-reach: correct accidental #include of C file Jonathan Nieder
2018-08-28 21:39 ` Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 05/18] upload-pack: make reachable() more generic Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 06/18] upload-pack: refactor ok_to_give_up() Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 07/18] upload-pack: generalize commit date cutoff Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 08/18] commit-reach: move can_all_from_reach_with_flags Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 09/18] test-reach: create new test tool for ref_newer Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 10/18] test-reach: test in_merge_bases Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 11/18] test-reach: test is_descendant_of Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 12/18] test-reach: test get_merge_bases_many Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 13/18] test-reach: test reduce_heads Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 14/18] test-reach: test can_all_from_reach_with_flags Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 15/18] test-reach: test commit_contains Derrick Stolee
2018-07-23 20:35 ` Jonathan Tan
2018-07-25 18:08 ` Junio C Hamano
2018-07-25 18:30 ` Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 16/18] commit-reach: replace ref_newer logic Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 17/18] commit-reach: make can_all_from_reach... linear Derrick Stolee
2018-07-23 20:41 ` Jonathan Tan
2018-08-01 20:41 ` Derrick Stolee
2018-09-12 4:14 ` Jeff King
2018-09-12 4:29 ` Jeff King
2018-09-12 13:08 ` Derrick Stolee
2018-07-20 16:33 ` [PATCH v2 18/18] commit-reach: use can_all_from_reach Derrick Stolee
2018-07-20 17:10 ` [PATCH v2 00/18] Consolidate reachability logic Stefan Beller
2018-07-20 17:15 ` Derrick Stolee
2018-07-20 22:16 ` Stefan Beller
2018-08-01 20:33 ` Derrick Stolee
2018-07-20 17:18 ` Derrick Stolee
2018-07-20 18:09 ` Eric Sunshine
2018-07-20 19:14 ` Derrick Stolee
2018-07-20 17:41 ` Duy Nguyen
2018-07-20 19:09 ` Derrick Stolee
2018-07-20 22:45 ` Junio C Hamano
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