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From: Derrick Stolee <stolee@gmail.com>
To: Elijah Newren <newren@gmail.com>,
	Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>, Jeff King <peff@peff.net>,
	Junio C Hamano <gitster@pobox.com>,
	Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH 1/3] commit-reach: implement get_reachable_subset
Date: Wed, 31 Oct 2018 07:54:43 -0400	[thread overview]
Message-ID: <d42eceda-0178-ce48-1ccd-7a1842e897ed@gmail.com> (raw)
In-Reply-To: <CABPp-BHbOWXsnUSdcptyQ_Cn_PnqH4On+Q3zWNZQV4QHgYhqpg@mail.gmail.com>

On 10/31/2018 2:07 AM, Elijah Newren wrote:
> On Tue, Oct 30, 2018 at 7:16 AM Derrick Stolee via GitGitGadget
> <gitgitgadget@gmail.com> wrote:
>> --- a/commit-reach.c
>> +++ b/commit-reach.c
>> @@ -688,3 +688,73 @@ int can_all_from_reach(struct commit_list *from, struct commit_list *to,
>>          object_array_clear(&from_objs);
>>          return result;
>>   }
>> +
>> +struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
>> +                                        struct commit **to, int nr_to,
>> +                                        int reachable_flag)
>> +{
>> +       struct commit **item;
>> +       struct commit *current;
>> +       struct commit_list *found_commits = NULL;
>> +       struct commit **to_last = to + nr_to;
>> +       struct commit **from_last = from + nr_from;
>> +       uint32_t min_generation = GENERATION_NUMBER_INFINITY;
>> +       int num_to_find = 0;
>> +
>> +       struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
>> +
>> +       for (item = to; item < to_last; item++) {
>> +               struct commit *c = *item;
>> +
>> +               parse_commit(c);
>> +               if (c->generation < min_generation)
>> +                       min_generation = c->generation;
> So, when we don't have a commit-graph, is c->generation just going to
> be 0, making min_generation also be 0? (meaning we get no possible
> speed benefit from the commit-graph, since we just don't have that
> information available)?

If we don't have a commit-graph, then we can only terminate the loop early
if we discover all of the commits (num_to_find == 0).Otherwise, we need to
walk the entire graph in order to determine non-reachability. This relates
to Junio's point about in_merge_bases_many(), which I'll respond to his
message in more detail about that.

Thanks,
-Stolee

  reply	other threads:[~2018-10-31 11:54 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-30 14:16 [PATCH 0/3] Make add_missing_tags() linear Derrick Stolee via GitGitGadget
2018-10-30 14:16 ` [PATCH 1/3] commit-reach: implement get_reachable_subset Derrick Stolee via GitGitGadget
2018-10-31  3:35   ` Junio C Hamano
2018-10-31 12:01     ` Derrick Stolee
2018-11-02  1:51       ` Junio C Hamano
2018-10-31  6:07   ` Elijah Newren
2018-10-31 11:54     ` Derrick Stolee [this message]
2018-10-30 14:16 ` [PATCH 2/3] test-reach: test get_reachable_subset Derrick Stolee via GitGitGadget
2018-10-30 14:16 ` [PATCH 3/3] remote: make add_missing_tags() linear Derrick Stolee via GitGitGadget
2018-10-31  3:05 ` [PATCH 0/3] Make " Junio C Hamano
2018-10-31  6:04 ` Elijah Newren
2018-10-31 12:05   ` Derrick Stolee
2018-11-01  6:52     ` Elijah Newren
2018-11-01 12:32       ` Derrick Stolee
2018-11-01 18:57         ` Elijah Newren
2018-11-01 19:02           ` Derrick Stolee
2018-11-02 14:58             ` Elijah Newren
2018-11-02 15:38               ` Derrick Stolee
2018-11-02 13:14 ` [PATCH v2 " Derrick Stolee via GitGitGadget
2018-11-02 13:14   ` [PATCH v2 1/3] commit-reach: implement get_reachable_subset Derrick Stolee via GitGitGadget
2018-11-02 13:14   ` [PATCH v2 2/3] test-reach: test get_reachable_subset Derrick Stolee via GitGitGadget
2018-11-02 13:14   ` [PATCH v2 3/3] remote: make add_missing_tags() linear Derrick Stolee via GitGitGadget

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