Remove the "Lazy initialization" in prep_exclude() left behind by aceb9429b37 (prep_exclude: remove the artificial PATH_MAX limit, 2014-07-14). Now that every caller who sets up a "struct dir_struct" is using the DIR_INIT macro we can rely on it to have done the initialization. As noted in an analysis of the previous control flow[1] an earlier passing of of "dir->basebuf.buf" to strncmp() wasn't buggy, as we'd only reach that code on subsequent invocations of prep_exclude(), i.e. after this strbuf_init() had been run. But keeping track of that makes for hard-to-read code. Let's just rely on the initialization instead. This does change the behavior of this code in that it won't be pre-growing the strbuf to a size of PATH_MAX. I think that's OK. That we were using PATH_MAX at all is just a relic from this being a fixed buffer from way back in f87f9497486 (git-ls-files: --exclude mechanism updates., 2005-07-24). Pre-allocating PATH_MAX was the opposite of an optimization in this case. I logged all "basebuf.buf" values when running the test suite, and by far the most common one (around 80%) is "", which we now won't allocate at all for, and just use the "strbuf_slopbuf". The second most common one was "a/", followed by other common cases of short relative paths. So using the default "struct strbuf" growth pattern is a much better allocation optimization in this case. 1. https://lore.kernel.org/git/87sfxhohsj.fsf@xxxxxxxxxxxxxxxxxxx/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> --- dir.c | 8 -------- dir.h | 4 +++- 2 files changed, 3 insertions(+), 9 deletions(-) diff --git a/dir.c b/dir.c index 39fce3bcba7..efc87c2e405 100644 --- a/dir.c +++ b/dir.c @@ -1550,14 +1550,6 @@ static void prep_exclude(struct dir_struct *dir, if (dir->pattern) return; - /* - * Lazy initialization. All call sites currently just - * memset(dir, 0, sizeof(*dir)) before use. Changing all of - * them seems lots of work for little benefit. - */ - if (!dir->basebuf.buf) - strbuf_init(&dir->basebuf, PATH_MAX); - /* Read from the parent directories and push them down. */ current = stk ? stk->baselen : -1; strbuf_setlen(&dir->basebuf, current < 0 ? 0 : current); diff --git a/dir.h b/dir.h index ff3b4a7f602..e3757c6099e 100644 --- a/dir.h +++ b/dir.h @@ -342,7 +342,9 @@ struct dir_struct { unsigned visited_directories; }; -#define DIR_INIT { 0 } +#define DIR_INIT { \ + .basebuf = STRBUF_INIT, \ +} struct dirent *readdir_skip_dot_and_dotdot(DIR *dirp); -- 2.33.0.1404.g83021034c5d
