Calvin Wan <calvinwan@xxxxxxxxxx> writes:
> Flatten out the if statements in match_stat_with_submodule so the
> logic is more readable and easier for future patches to add to.
>
> Move code that updates relevant variables from the end of
> run_diff_files to finish_run_diff_files. A future patch will utilize
> said function.
>
> Signed-off-by: Calvin Wan <calvinwan@xxxxxxxxxx>
> ---
> diff-lib.c | 71 ++++++++++++++++++++++++++++++++----------------------
> 1 file changed, 42 insertions(+), 29 deletions(-)
>
> diff --git a/diff-lib.c b/diff-lib.c
> index 7eb66a417a..2e148b79e6 100644
> --- a/diff-lib.c
> +++ b/diff-lib.c
> @@ -73,21 +73,50 @@ static int match_stat_with_submodule(struct diff_options *diffopt,
> unsigned *dirty_submodule)
> {
> int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);
> - if (S_ISGITLINK(ce->ce_mode)) {
> - struct diff_flags orig_flags = diffopt->flags;
> - if (!diffopt->flags.override_submodule_config)
> - set_diffopt_flags_from_submodule_config(diffopt, ce->name);
> - if (diffopt->flags.ignore_submodules)
> - changed = 0;
> - else if (!diffopt->flags.ignore_dirty_submodules &&
> - (!changed || diffopt->flags.dirty_submodules))
> - *dirty_submodule = is_submodule_modified(ce->name,
> - diffopt->flags.ignore_untracked_in_submodules);
> - diffopt->flags = orig_flags;
> + struct diff_flags orig_flags = diffopt->flags;
> + if (!S_ISGITLINK(ce->ce_mode))
> + goto cleanup;
> + if (!diffopt->flags.override_submodule_config)
> + set_diffopt_flags_from_submodule_config(diffopt, ce->name);
> + if (diffopt->flags.ignore_submodules) {
> + changed = 0;
> + goto cleanup;
> }
> + if (!diffopt->flags.ignore_dirty_submodules &&
> + (!changed || diffopt->flags.dirty_submodules))
> + *dirty_submodule = is_submodule_modified(ce->name,
> + diffopt->flags.ignore_untracked_in_submodules);
> +cleanup:
> + diffopt->flags = orig_flags;
> return changed;
> }
Unlike the original, this always makes two needless structure
assignments for anything that is not a submodule.
Can we fix that regression before moving forward?
Even when ce_mode is a gitlink, if .ignore_submodules bit is set,
the two structure assignments between diffopt->flags and orig_flags
become necessary, so the original was already doing extra copies but
we do not have to make it worse.
> +static void finish_run_diff_files(struct rev_info *revs,
> + struct cache_entry *ce,
> + struct index_state *istate,
> + int changed, int dirty_submodule,
> + unsigned int newmode)
> +{
> + unsigned int oldmode;
> + const struct object_id *old_oid, *new_oid;
> +
> + if (!changed && !dirty_submodule) {
> + ce_mark_uptodate(ce);
> + if (!S_ISGITLINK(ce->ce_mode))
> + mark_fsmonitor_valid(istate, ce);
> + if (!revs->diffopt.flags.find_copies_harder)
> + return;
> + }
> + oldmode = ce->ce_mode;
> + old_oid = &ce->oid;
> + new_oid = changed ? null_oid() : &ce->oid;
> + diff_change(&revs->diffopt, oldmode, newmode,
> + old_oid, new_oid,
> + !is_null_oid(old_oid),
> + !is_null_oid(new_oid),
> + ce->name, 0, dirty_submodule);
> +}
Strange indentation. It is unclear why this bottom 1/3 of the loop
body of run_diff_files() need to be a separate helper function,
while the top 2/3 does not. The resulting loop (below) becomes very
hard to follow because the reader cannot tell when diff_change() is
called and when it is not.
Overall, I see this change detrimental to diff-lib API at this step
in the series. Later steps may show something more rewarding than
the downsides we see here, hopefully.
