Re: [PATCH 1/2] serialize collection of changed submodules
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Sep 16, 2016, 17:27 UTC
- Message-ID
- <xmqqintvlpqv.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <20160914173124.GA7613@sandbox>
Heiko Voigt <hvoigt@hvoigt.net> writes:
Show 15 quoted lines
> +static struct sha1_array *get_sha1s_from_list(struct string_list *submodules,
> + const char *path)
> +{
> + struct string_list_item *item;
> + struct sha1_array *hashes;
> +
> + item = string_list_insert(submodules, path);
> + if (item->util)
> + return (struct sha1_array *) item->util;
> +
> + hashes = (struct sha1_array *) xmalloc(sizeof(struct sha1_array));
> + /* NEEDSWORK: should we add an initializer function for
> + * sha1_array ? */
> + memset(hashes, 0, sizeof(struct sha1_array));
> + item->util = hashes;/* NEEDSWORK: should we have SHA1_ARRAY_INIT etc.? */ item->util = xcalloc(1, sizeof(struct sha1_array));
Show 19 quoted lines
> static void collect_submodules_from_diff(struct diff_queue_struct *q,
> struct diff_options *options,
> void *data)
> {
> int i;
> - struct string_list *needs_pushing = data;
> + struct string_list *submodules = data;
>
> for (i = 0; i < q->nr; i++) {
> struct diff_filepair *p = q->queue[i];
> + struct sha1_array *hashes;
> if (!S_ISGITLINK(p->two->mode))
> continue;
> - if (submodule_needs_pushing(p->two->path, p->two->oid.hash))
> - string_list_insert(needs_pushing, p->two->path);
> + hashes = get_sha1s_from_list(submodules, p->two->path);
> + sha1_array_append(hashes, p->two->oid.hash);
> }
> }So the idea at this step is still let each commit in the top-level history inspected for any submodule change, but the result is collected in a mapping (submodule -> [ list of submodule commits ]). As we do not expect too many "oops, the old commit was better, so let's revert and rebind the old one from the submodule" in the history of the top-level, appending and then running for-each-unique is an efficient way, instead of first checking if we already have it and then inserting new ones to maintain the uniqueness.
Makes sense.
Show 18 quoted lines
> @@ -582,14 +601,41 @@ static void find_unpushed_submodule_commits(struct commit *commit,
> diff_tree_combined_merge(commit, 1, &rev);
> }
>
> +struct collect_submodule_from_sha1s_data {
> + char *submodule_path;
> + struct string_list *needs_pushing;
> +};
> +
> +static void collect_submodules_from_sha1s(const unsigned char sha1[20],
> + void *data)
> +{
> + struct collect_submodule_from_sha1s_data *me =
> + (struct collect_submodule_from_sha1s_data *) data;
> +
> + if (submodule_needs_pushing(me->submodule_path, sha1))
> + string_list_insert(me->needs_pushing, me->submodule_path);
> +}This is called from sha1_array_for_each_unique() that iterates over the submodule commit object names for one submodule and then ends up calling submodule_needs_pushing() number of times, which smells less efficient than it could be. You can ask
rev-list <all the submodule commits to be pushed> --not --remotes
just once in the submodule repository. I imagine that is what you'll do in the next patch.
An obvious but much less efficient way to optimize this part would be to see if me->needs_pushing already has me->submodule_path and skip the check for submodule_needs_pushing(), but if you drop the call by find_unpushed_submodule to sha1_array_for_each_unique() to walk new submodule commits one by one, that would become irrelevant.
Show 48 quoted lines
> +static void free_submodules_sha1s(struct string_list *submodules)
> +{
> + int i;
> + for (i = 0; i < submodules->nr; i++) {
> + struct string_list_item *item = &submodules->items[i];
> + struct sha1_array *hashes = (struct sha1_array *) item->util;
> + sha1_array_clear(hashes);
> + }
> + string_list_clear(submodules, 1);
> +}
> +
> int find_unpushed_submodules(unsigned char new_sha1[20],
> const char *remotes_name, struct string_list *needs_pushing)
> {
> struct rev_info rev;
> struct commit *commit;
> const char *argv[] = {NULL, NULL, "--not", "NULL", NULL};
> - int argc = ARRAY_SIZE(argv) - 1;
> + int argc = ARRAY_SIZE(argv) - 1, i;
> char *sha1_copy;
> + struct string_list submodules = STRING_LIST_INIT_DUP;
>
> struct strbuf remotes_arg = STRBUF_INIT;
>
> @@ -603,12 +649,23 @@ int find_unpushed_submodules(unsigned char new_sha1[20],
> die("revision walk setup failed");
>
> while ((commit = get_revision(&rev)) != NULL)
> - find_unpushed_submodule_commits(commit, needs_pushing);
> + find_unpushed_submodule_commits(commit, &submodules);
>
> reset_revision_walk();
> free(sha1_copy);
> strbuf_release(&remotes_arg);
>
> + for (i = 0; i < submodules.nr; i++) {
> + struct string_list_item *item = &submodules.items[i];
> + struct collect_submodule_from_sha1s_data data;
> + data.submodule_path = item->string;
> + data.needs_pushing = needs_pushing;
> + sha1_array_for_each_unique((struct sha1_array *) item->util,
> + collect_submodules_from_sha1s,
> + &data);
> + }
> + free_submodules_sha1s(&submodules);
> +
> return needs_pushing->nr;
> }