Subject: Re: [GSoC][PATCH 4/8] submodule: port submodule subcommand 'status' from shell to C

From: Brandon Williams <[email-masked]>
Date: Mon, 10 Jul 2017 16:38:24 -0700

On 07/11, Prathamesh Chavan wrote:
> This aims to make git-submodule 'status' a built-in. Hence, the function
> cmd_status() is ported from shell to C. This is done by introducing
> three functions: module_status(), submodule_status() and print_status().
> 
> The function module_status() acts as the front-end of the subcommand.
> It parses subcommand's options and then calls the function
> module_list_compute() for computing the list of submodules. Then
> this functions calls for_each_submodule_list() looping through the
> list obtained.
> 
> Then for_each_submodule_list() calls submodule_status() for each of the
> submodule in its list. The function submodule_status() is responsible
> for generating the status each submodule it is called for, and
> then calls print_status().
> 
> Finally, the function print_status() handles the printing of submodule's
> status.
> 
> Mentored-by: Christian Couder <[email-masked]>
> Mentored-by: Stefan Beller <[email-masked]>
> Signed-off-by: Prathamesh Chavan <[email-masked]>
> ---
>  builtin/submodule--helper.c | 154 ++++++++++++++++++++++++++++++++++++++++++++
>  git-submodule.sh            |  49 +-------------
>  2 files changed, 155 insertions(+), 48 deletions(-)
> 
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 80f744407..980b8ed27 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -560,6 +560,159 @@ static int module_init(int argc, const char **argv, const char *prefix)
>  	return 0;
>  }
>  
> +struct status_cb {
> +	const char *prefix;
> +	unsigned int quiet: 1;
> +	unsigned int recursive: 1;
> +	unsigned int cached: 1;
> +};
> +#define STATUS_CB_INIT { NULL, 0, 0, 0 }
> +
> +static void print_status(struct status_cb *info, char state, const char *path,
> +			 char *sub_sha1, char *displaypath)
> +{
> +	if (info->quiet)
> +		return;
> +
> +	printf("%c%s %s", state, sub_sha1, displaypath);
> +
> +	if (state == ' ' || state == '+') {
> +		struct argv_array name_rev_args = ARGV_ARRAY_INIT;

This struct needs to be cleared to prevent a memory leak.

> +
> +		argv_array_pushl(&name_rev_args, "print-name-rev",
> +				 path, sub_sha1, NULL);
> +		print_name_rev(name_rev_args.argc, name_rev_args.argv,
> +			       info->prefix);
> +	} else {
> +		printf("\n");
> +	}
> +}
> +
> +static void status_submodule(const struct cache_entry *list_item, void *cb_data)
> +{
> +	struct status_cb *info = cb_data;
> +	char *sub_sha1 = xstrdup(oid_to_hex(&list_item->oid));
> +	char *displaypath;
> +	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
> +
> +	if (!submodule_from_path(null_sha1, list_item->name))
> +		die(_("no submodule mapping found in .gitmodules for path '%s'"),
> +		      list_item->name);
> +
> +	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
> +
> +	if (list_item->ce_flags) {
> +		print_status(info, 'U', list_item->name,
> +			     sha1_to_hex(null_sha1), displaypath);
> +		goto cleanup;
> +	}
> +
> +	if (!is_submodule_active(the_repository, list_item->name)) {
> +		print_status(info, '-', list_item->name, sub_sha1, displaypath);
> +		goto cleanup;
> +	}
> +
> +	argv_array_pushl(&diff_files_args, "diff-files",
> +			 "--ignore-submodules=dirty", "--quiet", "--",
> +			 list_item->name, NULL);
> +
> +	/* NEEDSWORK: future optimization possible */

What sort of optimization? maybe you could document that?

> +	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
> +			    info->prefix)) {
> +		print_status(info, ' ', list_item->name, sub_sha1, displaypath);
> +	} else {
> +		if (!info->cached) {
> +			struct child_process cp = CHILD_PROCESS_INIT;
> +			struct strbuf sb = STRBUF_INIT;
> +
> +			prepare_submodule_repo_env(&cp.env_array);
> +			cp.git_cmd = 1;
> +			cp.dir = list_item->name;
> +
> +			argv_array_pushl(&cp.args, "rev-parse",
> +					 "--verify", "HEAD", NULL);
> +
> +			/* NEEDSWORK: future optimization possible */

Same here.

> +			if (capture_command(&cp, &sb, 0))
> +				die(_("could not run 'git rev-parse --verify"
> +				      "HEAD' in submodule %s"),
> +				      list_item->name);
> +
> +			strbuf_strip_suffix(&sb, "\n");
> +			print_status(info, '+', list_item->name, sb.buf,
> +				     displaypath);
> +			strbuf_release(&sb);
> +		} else {
> +			print_status(info, '+', list_item->name, sub_sha1,
> +				     displaypath);
> +		}
> +	}
> +
> +	if (info->recursive) {
> +		struct child_process cpr = CHILD_PROCESS_INIT;
> +
> +		cpr.git_cmd = 1;
> +		cpr.dir = list_item->name;
> +		prepare_submodule_repo_env(&cpr.env_array);
> +
> +		argv_array_pushl(&cpr.args, "--super-prefix", displaypath,
> +				 "submodule--helper", "status", "--recursive",
> +				 NULL);
> +
> +		if (info->cached)
> +			argv_array_push(&cpr.args, "--cached");
> +
> +		if (info->quiet)
> +			argv_array_push(&cpr.args, "--quiet");
> +
> +		if (run_command(&cpr))
> +			die(_("failed to recurse into submodule '%s'"),
> +			      list_item->name);
> +	}
> +
> +cleanup:
> +	free(displaypath);
> +	free(sub_sha1);
> +}
> +
> +static int module_status(int argc, const char **argv, const char *prefix)
> +{
> +	struct status_cb info = STATUS_CB_INIT;
> +	struct pathspec pathspec;
> +	struct module_list list = MODULE_LIST_INIT;
> +	int quiet = 0;
> +	int cached = 0;
> +	int recursive = 0;
> +
> +	struct option module_status_options[] = {
> +		OPT__QUIET(&quiet, N_("Suppress submodule status output")),
> +		OPT_BOOL(0, "cached", &cached, N_("Use commit stored in the index instead of the one stored in the submodule HEAD")),
> +		OPT_BOOL(0, "recursive", &recursive, N_("Recurse into nested submodules")),
> +		OPT_END()
> +	};
> +
> +	const char *const git_submodule_helper_usage[] = {
> +		N_("git submodule status [--quiet] [--cached] [--recursive] [<path>]"),
> +		NULL
> +	};
> +
> +	argc = parse_options(argc, argv, prefix, module_status_options,
> +			     git_submodule_helper_usage, 0);
> +
> +	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
> +		return 1;
> +
> +	info.prefix = prefix;
> +	info.quiet = !!quiet;
> +	info.recursive = !!recursive;
> +	info.cached = !!cached;
> +
> +	gitmodules_config();
> +	for_each_submodule_list(list, status_submodule, &info);
> +
> +	return 0;
> +}
> +
>  static int module_name(int argc, const char **argv, const char *prefix)
>  {
>  	const struct submodule *sub;
> @@ -1306,6 +1459,7 @@ static struct cmd_struct commands[] = {
>  	{"resolve-relative-url-test", resolve_relative_url_test, 0},
>  	{"print-name-rev", print_name_rev, 0},
>  	{"init", module_init, SUPPORT_SUPER_PREFIX},
> +	{"status", module_status, SUPPORT_SUPER_PREFIX},
>  	{"remote-branch", resolve_remote_submodule_branch, 0},
>  	{"push-check", push_check, 0},
>  	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
> diff --git a/git-submodule.sh b/git-submodule.sh
> index e988167e0..51b057d82 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -1005,54 +1005,7 @@ cmd_status()
>  		shift
>  	done
>  
> -	{
> -		git submodule--helper list --prefix "$wt_prefix" "$@" ||
> -		echo "#unmatched" $?
> -	} |
> -	while read -r mode sha1 stage sm_path
> -	do
> -		die_if_unmatched "$mode" "$sha1"
> -		name=$(git submodule--helper name "$sm_path") || exit
> -		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
> -		if test "$stage" = U
> -		then
> -			say "U$sha1 $displaypath"
> -			continue
> -		fi
> -		if ! git submodule--helper is-active "$sm_path" ||
> -		{
> -			! test -d "$sm_path"/.git &&
> -			! test -f "$sm_path"/.git
> -		}
> -		then
> -			say "-$sha1 $displaypath"
> -			continue;
> -		fi
> -		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
> -		then
> -			revname=$(git submodule--helper print-name-rev "$sm_path" "$sha1")
> -			say " $sha1 $displaypath$revname"
> -		else
> -			if test -z "$cached"
> -			then
> -				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
> -			fi
> -			revname=$(git submodule--helper print-name-rev "$sm_path" "$sha1")
> -			say "+$sha1 $displaypath$revname"
> -		fi
> -
> -		if test -n "$recursive"
> -		then
> -			(
> -				prefix="$displaypath/"
> -				sanitize_submodule_env
> -				wt_prefix=
> -				cd "$sm_path" &&
> -				eval cmd_status
> -			) ||
> -			die "$(eval_gettext "Failed to recurse into submodule path '\$sm_path'")"
> -		fi
> -	done
> +	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper status ${GIT_QUIET:+--quiet} ${cached:+--cached} ${recursive:+--recursive} "$@"
>  }
>  #
>  # Sync remote urls for submodules
> -- 
> 2.13.0
> 

-- 
Brandon Williams