builtin/submodule--helper: store update_clone information in a struct

The information that is printed for update_submodules in
'submodule--helper update-clone' and consumed by 'git submodule update'
is stored as a string per submodule. This made sense at the time of
48308681b0 (git submodule update: have a dedicated helper for cloning,
2016-02-29), but as we want to migrate the rest of the submodule update
into C, we're better off having access to the raw information in a helper
struct.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/submodule--helper.c

@@ -1446,6 +1446,12 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+struct update_clone_data {
+	const struct submodule *sub;
+	struct object_id oid;
+	unsigned just_cloned;
+};
+
 struct submodule_update_clone {
 	/* index into 'list', the list of submodules to look into for cloning */
 	int current;
@@ -1465,8 +1471,9 @@ struct submodule_update_clone {
 	const char *recursive_prefix;
 	const char *prefix;
 
-	/* Machine-readable status lines to be consumed by git-submodule.sh */
-	struct string_list projectlines;
+	/* to be consumed by git-submodule.sh */
+	struct update_clone_data *update_clone;
+	int update_clone_nr; int update_clone_alloc;
 
 	/* If we want to stop as fast as possible and return an error */
 	unsigned quickstop : 1;
@@ -1480,7 +1487,7 @@ struct submodule_update_clone {
 #define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
 	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, \
 	NULL, NULL, NULL, \
-	STRING_LIST_INIT_DUP, 0, NULL, 0, 0}
+	NULL, 0, 0, 0, NULL, 0, 0, 0}
 
 
 static void next_submodule_warn_missing(struct submodule_update_clone *suc,
@@ -1574,10 +1581,12 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 	strbuf_addf(&sb, "%s/.git", ce->name);
 	needs_cloning = !file_exists(sb.buf);
 
-	strbuf_reset(&sb);
-	strbuf_addf(&sb, "dummy %s %d\t%s\n",
-		    oid_to_hex(&ce->oid), needs_cloning, ce->name);
-	string_list_append(&suc->projectlines, sb.buf);
+	ALLOC_GROW(suc->update_clone, suc->update_clone_nr + 1,
+		   suc->update_clone_alloc);
+	oidcpy(&suc->update_clone[suc->update_clone_nr].oid, &ce->oid);
+	suc->update_clone[suc->update_clone_nr].just_cloned = needs_cloning;
+	suc->update_clone[suc->update_clone_nr].sub = sub;
+	suc->update_clone_nr++;
 
 	if (!needs_cloning)
 		goto cleanup;
@@ -1720,7 +1729,8 @@ static int git_update_clone_config(const char *var, const char *value,
 
 static int update_submodules(struct submodule_update_clone *suc)
 {
-	struct string_list_item *item;
+	int i;
+	struct strbuf sb = STRBUF_INIT;
 
 	run_processes_parallel(suc->max_jobs,
 			       update_clone_get_next_task,
@@ -1739,9 +1749,16 @@ static int update_submodules(struct submodule_update_clone *suc)
 	if (suc->quickstop)
 		return 1;
 
-	for_each_string_list_item(item, &suc->projectlines)
-		fprintf(stdout, "%s", item->string);
+	for (i = 0; i < suc->update_clone_nr; i++) {
+		strbuf_addf(&sb, "dummy %s %d\t%s\n",
+			oid_to_hex(&suc->update_clone[i].oid),
+			suc->update_clone[i].just_cloned,
+			suc->update_clone[i].sub->path);
+		fprintf(stdout, "%s", sb.buf);
+		strbuf_reset(&sb);
+	}
 
+	strbuf_release(&sb);
 	return 0;
 }