Function update_submodules

builtin/submodule--helper.c:2908–2978

}

static int update_submodules(struct update_data *update_data)
{
	int i, ret = 0;
	struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT;
	const struct run_process_parallel_opts opts = {
		.tr2_category = "submodule",
		.tr2_label = "parallel/update",

		.processes = update_data->max_jobs,

		.get_next_task = update_clone_get_next_task,
		.start_failure = update_clone_start_failure,
		.task_finished = update_clone_task_finished,
		.data = &suc,
	};

	suc.update_data = update_data;
	run_processes_parallel(&opts);

	/*
	 * We saved the output and put it out all at once now.
	 * That means:
	 * - the listener does not have to interleave their (checkout)
	 *   work with our fetching.  The writes involved in a
	 *   checkout involve more straightforward sequential I/O.
	 * - the listener can avoid doing any work if fetching failed.
	 */
	if (suc.quickstop) {
		ret = 1;
		goto cleanup;
	}

	for (i = 0; i < suc.update_clone_nr; i++) {
		struct update_clone_data ucd = suc.update_clone[i];
		int code = 128;

		oidcpy(&update_data->oid, &ucd.oid);
		update_data->just_cloned = ucd.just_cloned;
		update_data->sm_path = ucd.sub->path;

		/*
		 * Verify that the submodule path does not contain any
		 * symlinks; if it does, it might have been tampered with.
		 * TODO: allow exempting it via
		 * `safe.submodule.path` or something
		 */
		if (validate_submodule_path(update_data->sm_path) < 0)
			goto fail;

		code = ensure_core_worktree(update_data->sm_path);
		if (code)
			goto fail;

		update_data->displaypath = get_submodule_displaypath(
			update_data->sm_path, update_data->prefix,
			update_data->super_prefix);
		code = update_submodule(update_data);
		FREE_AND_NULL(update_data->displaypath);