On Mon, May 17, 2021 at 6:51 AM Derrick Stolee <stolee@xxxxxxxxx> wrote:
>
> On 5/3/21 10:12 PM, Elijah Newren via GitGitGadget wrote:
> > From: Elijah Newren <newren@xxxxxxxxx>
> >
> > Fill in cache_pairs, cached_target_names, and cached_irrelevant based on
> > rename detection results. Future commits will make use of these values.
>
> Thank you for continuing to break this down into nice-sized pieces.
>
> > +static void possibly_cache_new_pair(struct rename_info *renames,
> > + struct diff_filepair *p,
> > + unsigned side,
> > + char *new_path)
> > +{
> > + char *old_value;
> > + int dir_renamed_side = 0;
> > +
> > + if (new_path) {
> > + /*
> > + * Directory renames happen on the other side of history from
> > + * the side that adds new files to the old directory.
> > + */
> > + dir_renamed_side = 3 - side;
>
> Neat trick. Side is in { 1, 2 } so this makes sense.
>
> > + } else {
> > + int val = strintmap_get(&renames->relevant_sources[side],
> > + p->one->path);
> > + if (val == RELEVANT_NO_MORE) {
> > + assert(p->status == 'D');
> > + strset_add(&renames->cached_irrelevant[side],
> > + p->one->path);
>
> Ok, I see a transition here from a relevant side to an
> irrelevant one.
>
> > + }
> > + if (val <= 0)
> > + return;
> > + }
> > +
> > + if (p->status == 'D') {
> > + /*
> > + * If we already had this delete, we'll just set it's value
> > + * to NULL again, so no harm.
> > + */
> > + strmap_put(&renames->cached_pairs[side], p->one->path, NULL);
> > + } else if (p->status == 'R') {
> > + if (new_path) {
> > + new_path = xstrdup(new_path);
> > + old_value = strmap_put(&renames->cached_pairs[dir_renamed_side],
> > + p->two->path, new_path);
> > + strset_add(&renames->cached_target_names[dir_renamed_side],
> > + new_path);
> > + assert(!old_value);
>
> This assert implies that p->status == 'R' only if this is the
> first side (and first commit) to show a rename, right?
Um, this assert implies that p->two->path was not already found in
renames->cached_pairs[dir_renamed_side].
>
> > + }
> > + if (!new_path)
> > + new_path = p->two->path;
> > + new_path = xstrdup(new_path);
>
> If new_path was provided as non-NULL, then this is the second
> time we are dup-ing it. However, that seems correct because we
> want a different copy or every time we add it to the cached_pairs
> and cached_target_names data.
>
> > + old_value = strmap_put(&renames->cached_pairs[side],
> > + p->one->path, new_path);
> > + strset_add(&renames->cached_target_names[side],
> > + new_path);
>
> Since we appear to be doing this in multiple places, would this
> be a good place for a helper method? We could have it take a
> `const char *new_path` and have the helper manage the `xstrdup()`
> so we never forget to do that exactly once per insert to these
> sets.
Makes sense.
> > + free(old_value);
> > + } else if (p->status == 'A' && new_path) {
> > + new_path = xstrdup(new_path);
> > + old_value = strmap_put(&renames->cached_pairs[dir_renamed_side],
> > + p->two->path, new_path);
> > + strset_add(&renames->cached_target_names[dir_renamed_side],
> > + new_path);
> > + assert(!old_value);
>
> And here's the third instance, making the "three is many" rule
> kick in. A helper method would help make this easier. You can
> also have a parameter corresponding to whether you need to
> free() the old_value or assert it is NULL.
Yep, I'll add a helper.
>
> > + }
> > +}
> > +
> > static int compare_pairs(const void *a_, const void *b_)
> > {
> > const struct diff_filepair *a = *((const struct diff_filepair **)a_);
> > @@ -2415,6 +2474,7 @@ static int collect_renames(struct merge_options *opt,
> > char *new_path; /* non-NULL only with directory renames */
> >
> > if (p->status != 'A' && p->status != 'R') {
> > + possibly_cache_new_pair(renames, p, side_index, NULL);
> > diff_free_filepair(p);
> > continue;
> > }
> > @@ -2426,11 +2486,11 @@ static int collect_renames(struct merge_options *opt,
> > &collisions,
> > &clean);
> >
> > + possibly_cache_new_pair(renames, p, side_index, new_path);
> > if (p->status != 'R' && !new_path) {
> > diff_free_filepair(p);
> > continue;
> > }
> > -
>
> nit: this deletion seems unnecessary.
Will fix.
> > if (new_path)
> > apply_directory_rename_modifications(opt, p, new_path);
> >
> > @@ -3701,8 +3761,16 @@ static void merge_start(struct merge_options *opt, struct merge_result *result)
> > NULL, 1);
> > strmap_init_with_options(&renames->dir_renames[i],
> > NULL, 0);
> > + /*
> > + * relevant_sources uses -1 for the default, because we need
> > + * to be able to distinguish not-in-strintmap from valid
> > + * relevant_source values from enum file_rename_relevance.
> > + * In particular, possibly_cache_new_pair() expects a negative
> > + * value for not-found entries.
> > + */
> > strintmap_init_with_options(&renames->relevant_sources[i],
> > - 0, NULL, 0);
> > + -1 /* explicitly invalid */,
> > + NULL, 0);
> > strmap_init_with_options(&renames->cached_pairs[i],
> > NULL, 1);
> > strset_init_with_options(&renames->cached_irrelevant[i],
> >
>
> Functionally looks good. I just had some nits about organization.
As always, thanks for the review and the helpful suggestions!
