Nguyễn Thái Ngọc Duy <pclo...@gmail.com> writes:
> Instead of a custom commit walker like get_shallow_commits(), this new
> function uses rev-list to mark NOT_SHALLOW to all reachable commits,
> except borders. The definition of reachable is to be defined by the
> protocol later. This makes it more flexible to define shallow boundary.
>
> Note: if a commit has one NOT_SHALLOW parent and one SHALLOW parent,
> then it's considered the boundary. Which means in the client side, this
> commit has _no_ parents. This could lead to surprising cuts if we're not
> careful.
>
> Another option is to include more commits and only mark commits whose
> all parents are SHALLOW as boundary.
The second and third are greek to me at this point ;-) but hopefully
they will become clear as we read on.
> +/*
> + * Given rev-list arguments, run rev-list. All reachable commits
> + * except border ones are marked with not_shallow_flag. Border commits
> + * are marked with shallow_flag. The list of border/shallow commits
> + * are also returned.
> + */
> +struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
> + int shallow_flag,
> + int not_shallow_flag)
> +{
> + struct commit_list *result = NULL, *p;
> + struct rev_info revs;
> + unsigned int i, nr;
> +
> + /*
> + * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
> + * set at this point. But better be safe than sorry.
> + */
> + nr = get_max_object_index();
> + for (i = 0; i < nr; i++) {
> + struct object *o = get_indexed_object(i);
> + if (!o || o->type != OBJ_COMMIT)
> + continue;
> + o->flags &= ~(shallow_flag | not_shallow_flag);
> + }
This is slightly different from clear_object_flags(), but I cannot
tell if it is intended, or if you forgot that the function exists.
> + is_repository_shallow(); /* make sure shallows are read */
> +
> + init_revisions(&revs, NULL);
> + save_commit_buffer = 0;
> + setup_revisions(ac, av, &revs, NULL);
> +
> + /* Mark all reachable commits as NOT_SHALLOW */
> + if (prepare_revision_walk(&revs))
> + die("revision walk setup failed");
> + traverse_commit_list(&revs, show_commit, NULL, ¬_shallow_flag);
> +
> + /*
> + * mark border commits SHALLOW + NOT_SHALLOW.
> + * We cannot clear NOT_SHALLOW right now. Imagine border
> + * commit A is processed first, then commit B, whose parent is
> + * A, later. If NOT_SHALLOW on A is cleared at step 1, B
> + * itself is considered border at step 2, which is incorrect.
> + */
> + nr = get_max_object_index();
> + for (i = 0; i < nr; i++) {
I'd really like not to see a loop over 0..get_max_object_index().
Are there many codepaths that peek into the in-core entire object
store already? Would it work equally well to keep track of the
commits discovered in show_commit() to use as the set of commits
you need to visit in this second pass?
> + struct object *o = get_indexed_object(i);
> + struct commit *c = (struct commit *)o;
> +
> + if (!o || o->type != OBJ_COMMIT ||
> + !(o->flags & not_shallow_flag))
> + continue;
> +
> + if (parse_commit(c))
> + die("unable to parse commit %s",
> + oid_to_hex(&c->object.oid));
> +
> + for (p = c->parents; p; p = p->next)
> + if (!(p->item->object.flags & not_shallow_flag)) {
> + o->flags |= shallow_flag;
> + commit_list_insert(c, &result);
> + break;
> + }
> + }
> +
> + /*
> + * Now we can clean up NOT_SHALLOW on border commits. Having
> + * both flags set can confuse the caller.
> + */
> + for (p = result; p; p = p->next) {
> + struct object *ro = &p->item->object;
Why "ro" only in this third pass, unlike the other two passes that
said "o" which is in a sense more descriptive?
> + if ((ro->flags & not_shallow_flag) &&
> + (ro->flags & shallow_flag))
If you introduce a "both_flags = shallow_flag | not_shallow_flag"
at the very beginning, this will become
if (o->flags & both_flags)
o->flags &= ~not_shallow_flag;
which would probably be easier to read. You can pass the same to
clear_object_flags() at the first pass.
> + ro->flags &= ~not_shallow_flag;
> + }
> + return result;
> +}
Other than that, this step looks quite straight-forward to me.
Thanks.
> +
> static void check_shallow_file_for_update(void)
> {
> if (is_shallow == -1)
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