log: avoid loading decorations for userformats that don't need it

If no --decorate option is given, we default to auto-decoration. And
when that kicks in, cmd_log_init_finish() will unconditionally load the
decoration refs.

However, if we are using a user-format that does not include "%d" or
"%D", we won't show the decorations at all, so we don't need to load
them. We can detect this case and auto-disable them by adding a new
field to our userformat_want helper. We can do this even when the user
explicitly asked for --decorate, because it can't affect the output at
all.

This patch consistently reduces the time to run "git log -1 --format=%H"
on my git.git clone (with ~2k refs) from 34ms to 7ms. On a much more
extreme real-world repository (with ~220k refs), it goes from 2.5s to
4ms.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2021-06-22 12:04:50 -04:00 коммит произвёл Junio C Hamano
Родитель 3c7e2e8f0a
Коммит b2086b5183
3 изменённых файлов: 8 добавлений и 0 удалений

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@ -245,6 +245,9 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
rev->abbrev_commit = 0;
}
if (rev->commit_format == CMIT_FMT_USERFORMAT && !w.decorate)
decoration_style = 0;
if (decoration_style) {
const struct string_list *config_exclude =
repo_config_get_value_multi(the_repository,

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@ -1735,6 +1735,10 @@ static size_t userformat_want_item(struct strbuf *sb, const char *placeholder,
case 'S':
w->source = 1;
break;
case 'd':
case 'D':
w->decorate = 1;
break;
}
return 0;
}

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@ -73,6 +73,7 @@ static inline int cmit_fmt_is_mail(enum cmit_fmt fmt)
struct userformat_want {
unsigned notes:1;
unsigned source:1;
unsigned decorate:1;
};
void userformat_find_requirements(const char *fmt, struct userformat_want *w);