Re: [PATCHv3 3/4] gitweb: separate heads and remotes lists

["Giuseppe Bilotta" <giuseppe.bilotta@gmail.com>]

On Sun, Nov 16, 2008 at 6:34 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Giuseppe Bilotta <giuseppe.bilotta@gmail.com> writes:
>> -     my @headlist = git_get_heads_list(16);
>> +     my @headlist = git_get_heads_list(16, 'heads');
>> +     my @remotelist = $remote_heads ? git_get_heads_list(16, 'remotes') : ();
>
> Wasteful to run one for-each-ref for each list.
>
> You earlier introduced $ref_item{'class'} so that you can differenciate
> what you got from git_get_heads_list(); make use of it, perhaps like:
>
>        my @heads_list = git_get_heads_list(16, \%head_class);
>        my @headlist = grep { $_->{'class'} eq 'head' } @heads_list;
>        my @remotelist = grep { $_->{'class'} eq 'remote' } @heads_list;
>
> By the way, your [2/4] used "heads" and "remotes" as class, while your
> [1/4] stored 'head' and 'remote' in $ref_item{'class'}.  Notice the above
> suggestion corrects this discrepancy as well.

Although I agree with the head_class idea, I would like to point out
that doing a single git call to retrieve all refs and then selecting
the ones we want and doing multiple git calls are not equivalent.

First of all, with multiple calls we can limit the calls to retrieve
at most 16 refs of each kind, whereas this cannot be done with a
single call for all the refs. I'm not sure however, performance-wise,
if it's faster to filter the first 16 refs of each after retrieving
all of them, or doing multiple calls, especially with lots of refs.

Moreover, gitweb is already doing multiple for-each-ref calls to get
tags and heads. I guess that at this point we could go the extra mile
and include tags in the refs management. Of course, the problem of how
to handle the rate limiting remains.


-- 
Giuseppe "Oblomov" Bilotta