[GSoC][PATCH 1/4] submodule--helper: introduce get_submodule_displaypath()

[GSoC][PATCH 1/4] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
As said in the previous update,
a short patch series is floated for the maintainer's review,
and is consisting of the following changes:
* introduce function get_submodule_displaypath()
* introduce function for_each_submodule_list()
* port function set_name_rev() from shell to C
* port submodule subcommand 'status' from shell to C

The complete build report for the above series of patches is available
at:
https://travis-ci.org/pratham-pc/git/builds
Branch: week-14-1
Build #158
The above changes are also push on github and are available at:
https://github.com/pratham-pc/git/commits/week-14-1

The above changes were based on master branch.
But along with the above changes, the same series was also applied
to a separate branch based on the 'next' branch. The changes were
applicable without any additional changes to the patches.
Complete build report of that is also available at:
https://travis-ci.org/pratham-pc/git/builds
Branch: week-14-1-next
Build #159
The above changes are also push on github and are available at:
https://github.com/pratham-pc/git/commits/week-14-1-next

 builtin/submodule--helper.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 84562ec83..dcdbde963 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -220,6 +220,27 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		int len = strlen(super_prefix);
+		const char *format = is_dir_sep(super_prefix[len - 1]) ? "%s%s" : "%s/%s";
+		return xstrfmt(format, super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -339,16 +360,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 	/* Only loads from .gitmodules, no overlay with .git/config */
 	gitmodules_config();
-
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -363,7 +375,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 	}
-- 
2.13.0

[GSoC][PATCH 2/4] submodule--helper: introduce for_each_submodule_list()

[Prathamesh Chavan]

Introduce function for_each_submodule_list() and
replace a loop in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index dcdbde963..7803457ba 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,9 @@
 #include "refs.h"
 #include "connect.h"
 
+typedef void (*submodule_list_func_t)(const struct cache_entry *list_item,
+				      void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -352,17 +355,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_submodule_list(const struct module_list list,
+				    submodule_list_func_t fn, void *cb_data)
 {
+	int i;
+	for (i = 0; i < list.nr; i++)
+		fn(list.entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+};
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct init_cb *info = cb_data;
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	/* Only loads from .gitmodules, no overlay with .git/config */
-	gitmodules_config();
-	displaypath = get_submodule_displaypath(path, prefix);
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(&null_oid, list_item->name);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -374,7 +390,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 *
 	 * Set active flag for the submodule being initialized
 	 */
-	if (!is_submodule_active(the_repository, path)) {
+	if (!is_submodule_active(the_repository, list_item->name)) {
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 	}
@@ -416,7 +432,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!info->quiet)
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -445,10 +461,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -473,8 +489,11 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	info.quiet = !!quiet;
+
+	gitmodules_config();
+	for_each_submodule_list(list, init_submodule, &info);
 
 	return 0;
 }
-- 
2.13.0

[GSoC][PATCH 3/4] submodule: port set_name_rev() from shell to C

[Prathamesh Chavan]

Function set_name_rev() is ported from git-submodule to the
submodule--helper builtin. The function get_name_rev() generates the
value of the revision name as required, and the function
print_name_rev() handles the formating and printing of the obtained
revision name.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            | 16 ++----------
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 7803457ba..a4bff3f38 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -244,6 +244,68 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *get_name_rev(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = {
+		NULL
+	};
+
+	static const char *describe_tags[] = {
+		"--tags", NULL
+	};
+
+	static const char *describe_contains[] = {
+		"--contains", NULL
+	};
+
+	static const char *describe_all_always[] = {
+		"--all", "--always", NULL
+	};
+
+	static const char **describe_argv[] = {
+		describe_bare, describe_tags, describe_contains,
+		describe_all_always, NULL
+	};
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0) && sb.len) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
+static int print_name_rev(int argc, const char **argv, const char *prefix)
+{
+	char *namerev;
+	if (argc != 3)
+		die("print-name-rev only accepts two arguments: <path> <sha1>");
+
+	namerev = get_name_rev(argv[1], argv[2]);
+	if (namerev && namerev[0])
+		printf(" (%s)", namerev);
+	printf("\n");
+
+	free(namerev);
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -1242,6 +1304,7 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
+	{"print-name-rev", print_name_rev, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"push-check", push_check, 0},
diff --git a/git-submodule.sh b/git-submodule.sh
index e131760ee..e988167e0 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -759,18 +759,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1042,14 +1030,14 @@ cmd_status()
 		fi
 		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
 		then
-			set_name_rev "$sm_path" "$sha1"
+			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 "$sm_path" && git rev-parse --verify HEAD)
 			fi
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper print-name-rev "$sm_path" "$sha1")
 			say "+$sha1 $displaypath$revname"
 		fi
 
-- 
2.13.0

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

[Prathamesh Chavan]

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 <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
The patch below underwent some changes after its previous version.

In the shell script, the submodules, which had merge-conflicts are
identified by checking if the $stage variable has the value 'U'
Till the last patch series, this was done by checking if ce_flags have
a non-zero value. In this new patch series, this was changed and
instead ce_stage() was called on the list_item(cache_entry), and then
we check whether it has a non-zero value.

 builtin/submodule--helper.c | 156 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  49 +-------------
 2 files changed, 157 insertions(+), 48 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index a4bff3f38..831370d6e 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -560,6 +560,161 @@ 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,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (info->quiet)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+') {
+		struct argv_array name_rev_args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&name_rev_args, "print-name-rev",
+				 path, oid_to_hex(oid), NULL);
+		print_name_rev(name_rev_args.argc, name_rev_args.argv,
+			       info->prefix);
+
+		argv_array_clear(&name_rev_args);
+	} else {
+		printf("\n");
+	}
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+
+	if (!submodule_from_path(&null_oid, 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 (ce_stage(list_item)) {
+		print_status(info, 'U', list_item->name,
+			     &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, list_item->name)) {
+		print_status(info, '-', list_item->name, &list_item->oid,
+			     displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 list_item->name, NULL);
+
+	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
+			    info->prefix)) {
+		print_status(info, ' ', list_item->name, &list_item->oid,
+			     displaypath);
+	} else {
+		if (!info->cached) {
+			struct object_id oid;
+
+			if (head_ref_submodule(list_item->name,
+					       handle_submodule_head_ref, &oid))
+				die(_("could not resolve HEAD ref inside the"
+				      "submodule '%s'"), list_item->name);
+
+			print_status(info, '+', list_item->name, &oid,
+				     displaypath);
+		} else {
+			print_status(info, '+', list_item->name,
+				     &list_item->oid, 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:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+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 +1461,7 @@ 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

Re: [GSoC][PATCH 3/4] submodule: port set_name_rev() from shell to C

[Heiko Voigt]

On Mon, Aug 21, 2017 at 09:45:14PM +0530, Prathamesh Chavan wrote:
> Function set_name_rev() is ported from git-submodule to the
> submodule--helper builtin. The function get_name_rev() generates the
> value of the revision name as required, and the function
> print_name_rev() handles the formating and printing of the obtained
> revision name.
> 
> Mentored-by: Christian Couder <christian.couder@gmail.com>
> Mentored-by: Stefan Beller <sbeller@google.com>
> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
>  builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
>  git-submodule.sh            | 16 ++----------
>  2 files changed, 65 insertions(+), 14 deletions(-)
> 
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 7803457ba..a4bff3f38 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c

[...]

> @@ -1242,6 +1304,7 @@ static struct cmd_struct commands[] = {
>  	{"relative-path", resolve_relative_path, 0},
>  	{"resolve-relative-url", resolve_relative_url, 0},
>  	{"resolve-relative-url-test", resolve_relative_url_test, 0},
> +	{"print-name-rev", print_name_rev, 0},

I see the function in git-submodule.sh was named kind of reverse. How
about we do it more naturally here and call this 'rev-name' instead?
That makes is more clear to me and is also similar to the used variable
name 'revname'.

I would also prefix it differently like 'get' or 'calculate' instead of
'print' since it tries to find a name and is not just a simple lookup.

So in summary I would prefer something like 'get-rev-name' as a name for
the subcommand here.

>  	{"init", module_init, SUPPORT_SUPER_PREFIX},
>  	{"remote-branch", resolve_remote_submodule_branch, 0},
>  	{"push-check", push_check, 0},
> diff --git a/git-submodule.sh b/git-submodule.sh
> index e131760ee..e988167e0 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -759,18 +759,6 @@ cmd_update()
>  	}
>  }
>  
> -set_name_rev () {
> -	revname=$( (
> -		sanitize_submodule_env
> -		cd "$1" && {
> -			git describe "$2" 2>/dev/null ||
> -			git describe --tags "$2" 2>/dev/null ||
> -			git describe --contains "$2" 2>/dev/null ||
> -			git describe --all --always "$2"
> -		}
> -	) )
> -	test -z "$revname" || revname=" ($revname)"
> -}
>  #
>  # Show commit summary for submodules in index or working tree
>  #
> @@ -1042,14 +1030,14 @@ cmd_status()
>  		fi
>  		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
>  		then
> -			set_name_rev "$sm_path" "$sha1"
> +			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 "$sm_path" && git rev-parse --verify HEAD)
>  			fi
> -			set_name_rev "$sm_path" "$sha1"
> +			revname=$(git submodule--helper print-name-rev "$sm_path" "$sha1")
>  			say "+$sha1 $displaypath$revname"
>  		fi
>  
> -- 
> 2.13.0
> 

Re: [GSoC][PATCH 3/4] submodule: port set_name_rev() from shell to C

[Prathamesh Chavan]

On Mon, Aug 21, 2017 at 10:17 PM, Heiko Voigt <hvoigt@hvoigt.net> wrote:
> On Mon, Aug 21, 2017 at 09:45:14PM +0530, Prathamesh Chavan wrote:
>> Function set_name_rev() is ported from git-submodule to the
>> submodule--helper builtin. The function get_name_rev() generates the
>> value of the revision name as required, and the function
>> print_name_rev() handles the formating and printing of the obtained
>> revision name.
>>
>> Mentored-by: Christian Couder <christian.couder@gmail.com>
>> Mentored-by: Stefan Beller <sbeller@google.com>
>> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
>> ---
>>  builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
>>  git-submodule.sh            | 16 ++----------
>>  2 files changed, 65 insertions(+), 14 deletions(-)
>>
>> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
>> index 7803457ba..a4bff3f38 100644
>> --- a/builtin/submodule--helper.c
>> +++ b/builtin/submodule--helper.c
>
> [...]
>
>> @@ -1242,6 +1304,7 @@ static struct cmd_struct commands[] = {
>>       {"relative-path", resolve_relative_path, 0},
>>       {"resolve-relative-url", resolve_relative_url, 0},
>>       {"resolve-relative-url-test", resolve_relative_url_test, 0},
>> +     {"print-name-rev", print_name_rev, 0},
>
> I see the function in git-submodule.sh was named kind of reverse. How
> about we do it more naturally here and call this 'rev-name' instead?
> That makes is more clear to me and is also similar to the used variable
> name 'revname'.

The functions 'print_name_rev()' and 'get_name_rev()' are the ported
C functions of the function 'set_name_rev()'
Their names were assigned so due to the existing function's name,
and hence to faithfully port the functions.

But, thanks for the above suggestion, and also for reviewing
the patch. I will update the names as print_rev_name() and
get_rev_name() respectively.
>
> I would also prefix it differently like 'get' or 'calculate' instead of
> 'print' since it tries to find a name and is not just a simple lookup.

The former function from the shell script, 'set_name_rev()' is split
into two functions, namely: 'print_name_rev()' and 'get_name_rev()'
The function print_name_rev() is just the front_end of the function,
and exists to printf the return value of the get_name_rev() function
is the required format.
Calculation of the value is actually done by the function
get_name_rev().
Hence, I named the functions the way they are.

Thanks,
Prathamesh Chavan

Re: [GSoC][PATCH 1/4] submodule--helper: introduce get_submodule_displaypath()

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> Introduce function get_submodule_displaypath() to replace the code
> occurring in submodule_init() for generating displaypath of the
> submodule with a call to it.

Looks like a quite straight-forward refactoring.

> +static char *get_submodule_displaypath(const char *path, const char *prefix)
> +{
> +	const char *super_prefix = get_super_prefix();
> +
> +	if (prefix && super_prefix) {
> +		BUG("cannot have prefix '%s' and superprefix '%s'",
> +		    prefix, super_prefix);
> +	} else if (prefix) {
> +		struct strbuf sb = STRBUF_INIT;
> +		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
> +		strbuf_release(&sb);
> +		return displaypath;

Use of xstrdup() would waste one extra allocation and copy, no?  In
other words, wouldn't this do the same thing?

	... {
		struct strbuf sb = STRBUF_INIT;

		relative_path(path, prefix, &sb);
	        return strbuf_detach(&sb, NULL);

> @@ -363,7 +375,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  	 * Set active flag for the submodule being initialized
>  	 */
>  	if (!is_submodule_active(the_repository, path)) {
> -		strbuf_reset(&sb);
>  		strbuf_addf(&sb, "submodule.%s.active", sub->name);
>  		git_config_set_gently(sb.buf, "true");
>  	}

This is because sb will stay untouched with the use of the new
helper.  With the way this single strbuf is reused throughout this
function, I cannot help wondering if the prevailing pattern of
resetting and then using is a mistake.  If the strbuf is mostly used
as a scratchpad, wouldn't it make more sense to use it and then
clean up when you are done with it?

I.e. something along this line that shows only two uses...

 builtin/submodule--helper.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 0ff9dd0b85..84ded4b2e9 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -363,9 +363,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -373,7 +373,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -410,9 +409,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {

Re: [GSoC][PATCH 2/4] submodule--helper: introduce for_each_submodule_list()

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> -static void init_submodule(const char *path, const char *prefix, int quiet)
> +static void for_each_submodule_list(const struct module_list list,
> +				    submodule_list_func_t fn, void *cb_data)

It may not be wrong per-se, but can't this just be for_each_submodule()?

Your "justification" may be that this makes it clear that you are
iterating over module_list and not other kind of group of
submodules, but I would say the design of the subsystem is broken if
some places use a list of submodules while some other places use an
array of submodules to represent a group of submodules.  Especially
when there is a dedicated type to hold a group of submodules,
i.e. struct module-list, that type should be used consistently
throughout the subsystem and API, no?

>  {
> +	int i;
> +	for (i = 0; i < list.nr; i++)
> +		fn(list.entries[i], cb_data);
> +}

Also, did you really want to pass the structure by value?  At least
in C, it is more customary to pass these things by pointer, i.e.

	for_each_submodule(struct module_list *list,
			   for_each_submodule_fn fn,
			   void *cb_data)
	{
		for (i = 0; i < list->nr; i++)
			...

Otherwise you'd be making a copy on stack unnecessarily (ok, "const"
might hint a smart compiler to turn this inefficient code to pass it
by pointer, but I do not think it is a particulary good to rely on
such things).

[GSoC][PATCH v2 0/4] submodule: Incremental rewrite of git-submodules

[Prathamesh Chavan]

Changes in v2:

* In the function get_submodule_displaypath(), I tried avoiding the extra
  memory allocation, but it rather invoked test 5 from
  t7406-submodule-update. The details of the test failiure can be seen
  in the build report as well. (Build #162)
  This failure occured as even though the function relative_path(),
  returned the value correctly, NULL was stored in sb.buf
  Hence currently the function is still using the old way of
  allocating extra memory and releasing the strbuf first, and return
  the extra allocated memory.
* It was observed that strbuf_reset was being done just before the strbuf
  was being reused. It made more sense to reset them just after their use 
  instead. Hence, these function calls of strbuf_reset() were moved
  accordingly.
  (The above change was limited to the function init_submodule() only,
   since already there was a deletion of one such funciton call,
   and IMO, it won't be suitable to carryout the operation for the complete
   file in the same commit.)
* The function name for_each_submodule_list() was changed to
  for_each_submodule().
* Instead of passing the complete list to the function for_each_submodule(),
  only its pointer is passed to avoid the compiler from making copy of the
  list, and to make the code more efficient.
* The function names of print_name_rev() and get_name_rev() were changed
  to get_rev_name() and compute_rev_name(). Now the function get_rev_name()
  acts as the front end of the subcommand and calls the function
  compute_rev_name() for generating and receiving the value of revision name.
* The above change was also accompanied by the change in names of some
  variables used internally in the functions.

As before you can find this series at: 
https://github.com/pratham-pc/git/commits/week-14-1

And the build report is available at: 
https://travis-ci.org/pratham-pc/git/builds/
Branch: week-14-1
Build #163

Prathamesh Chavan (4):
  submodule--helper: introduce get_submodule_displaypath()
  submodule--helper: introduce for_each_submodule()
  submodule: port set_name_rev() from shell to C
  submodule: port submodule subcommand 'status' from shell to C

 builtin/submodule--helper.c | 294 ++++++++++++++++++++++++++++++++++++++++----
 git-submodule.sh            |  61 +--------
 2 files changed, 273 insertions(+), 82 deletions(-)

-- 
2.13.0

[GSoC][PATCH v2 1/4] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 38 +++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 84562ec83..e666f84ba 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -220,6 +220,28 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		int len = strlen(super_prefix);
+		const char *format = is_dir_sep(super_prefix[len - 1]) ? "%s%s" : "%s/%s";
+
+		return xstrfmt(format, super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -339,16 +361,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 	/* Only loads from .gitmodules, no overlay with .git/config */
 	gitmodules_config();
-
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -363,9 +376,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -373,7 +386,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -410,9 +422,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
-- 
2.13.0

[GSoC][PATCH v2 2/4] submodule--helper: introduce for_each_submodule()

[Prathamesh Chavan]

Introduce function for_each_submodule() and replace a loop
in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index e666f84ba..847fba854 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,9 @@
 #include "refs.h"
 #include "connect.h"
 
+typedef void (*submodule_list_func_t)(const struct cache_entry *list_item,
+				      void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -353,17 +356,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_submodule(const struct module_list *list,
+			       submodule_list_func_t fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+};
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const struct cache_entry *list_item, void *cb_data)
 {
+	struct init_cb *info = cb_data;
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	/* Only loads from .gitmodules, no overlay with .git/config */
-	gitmodules_config();
-	displaypath = get_submodule_displaypath(path, prefix);
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(&null_oid, list_item->name);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -375,7 +391,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 *
 	 * Set active flag for the submodule being initialized
 	 */
-	if (!is_submodule_active(the_repository, path)) {
+	if (!is_submodule_active(the_repository, list_item->name)) {
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 		strbuf_reset(&sb);
@@ -417,7 +433,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!info->quiet)
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -446,10 +462,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -474,8 +490,11 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	info.quiet = !!quiet;
+
+	gitmodules_config();
+	for_each_submodule(&list, init_submodule, &info);
 
 	return 0;
 }
-- 
2.13.0

[GSoC][PATCH v2 3/4] submodule: port set_name_rev() from shell to C

[Prathamesh Chavan]

Function set_name_rev() is ported from git-submodule to the
submodule--helper builtin. The function compute_rev_name() generates the
value of the revision name as required.
The function get_rev_name() calls compute_rev_name() and receives the
revision name, and later handles its formating and printing.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            | 16 ++----------
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 847fba854..6ae93ce38 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -245,6 +245,68 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = {
+		NULL
+	};
+
+	static const char *describe_tags[] = {
+		"--tags", NULL
+	};
+
+	static const char *describe_contains[] = {
+		"--contains", NULL
+	};
+
+	static const char *describe_all_always[] = {
+		"--all", "--always", NULL
+	};
+
+	static const char **describe_argv[] = {
+		describe_bare, describe_tags, describe_contains,
+		describe_all_always, NULL
+	};
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0) && sb.len) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
+static int get_rev_name(int argc, const char **argv, const char *prefix)
+{
+	char *revname;
+	if (argc != 3)
+		die("get-rev-name only accepts two arguments: <path> <sha1>");
+
+	revname = compute_rev_name(argv[1], argv[2]);
+	if (revname && revname[0])
+		printf(" (%s)", revname);
+	printf("\n");
+
+	free(revname);
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -1243,6 +1305,7 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
+	{"get-rev-name", get_rev_name, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"push-check", push_check, 0},
diff --git a/git-submodule.sh b/git-submodule.sh
index e131760ee..91f043ec6 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -759,18 +759,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1042,14 +1030,14 @@ cmd_status()
 		fi
 		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
 		then
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say " $sha1 $displaypath$revname"
 		else
 			if test -z "$cached"
 			then
 				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
 			fi
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say "+$sha1 $displaypath$revname"
 		fi
 
-- 
2.13.0

[GSoC][PATCH v2 4/4] submodule: port submodule subcommand 'status' from shell to C

[Prathamesh Chavan]

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() looping through the
list obtained.

Then for_each_submodule() 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 <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 156 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  49 +-------------
 2 files changed, 157 insertions(+), 48 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 6ae93ce38..933073251 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -561,6 +561,161 @@ 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,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (info->quiet)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+') {
+		struct argv_array get_rev_args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&get_rev_args, "get-rev-name",
+				 path, oid_to_hex(oid), NULL);
+		get_rev_name(get_rev_args.argc, get_rev_args.argv,
+			     info->prefix);
+
+		argv_array_clear(&get_rev_args);
+	} else {
+		printf("\n");
+	}
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+
+	if (!submodule_from_path(&null_oid, 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 (ce_stage(list_item)) {
+		print_status(info, 'U', list_item->name,
+			     &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, list_item->name)) {
+		print_status(info, '-', list_item->name, &list_item->oid,
+			     displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 list_item->name, NULL);
+
+	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
+			    info->prefix)) {
+		print_status(info, ' ', list_item->name, &list_item->oid,
+			     displaypath);
+	} else {
+		if (!info->cached) {
+			struct object_id oid;
+
+			if (head_ref_submodule(list_item->name,
+					       handle_submodule_head_ref, &oid))
+				die(_("could not resolve HEAD ref inside the"
+				      "submodule '%s'"), list_item->name);
+
+			print_status(info, '+', list_item->name, &oid,
+				     displaypath);
+		} else {
+			print_status(info, '+', list_item->name,
+				     &list_item->oid, 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:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+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, status_submodule, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1307,6 +1462,7 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"get-rev-name", get_rev_name, 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 91f043ec6..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=$(git submodule--helper get-rev-name "$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 get-rev-name "$sm_path" "$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

Re: [GSoC][PATCH v2 2/4] submodule--helper: introduce for_each_submodule()

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> +typedef void (*submodule_list_func_t)(const struct cache_entry *list_item,
> +				      void *cb_data);
> +
>  static char *get_default_remote(void)
>  {
>  	char *dest = NULL, *ret;
> @@ -353,17 +356,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
>  	return 0;
>  }
>  
> -static void init_submodule(const char *path, const char *prefix, int quiet)
> +static void for_each_submodule(const struct module_list *list,
> +			       submodule_list_func_t fn, void *cb_data)

In the output from

	$ git grep for_each \*.h

we find that the convention is that an interator over a group of X
is for_each_X, the callback function that is given to for_each_X is
of type each_X_fn.  An interator over a subset of group of X that
has trait Y, for_each_Y_X() iterates and calls back a function of
type each_X_fn (e.g. for_each_tag_ref() still calls each_ref_fn).

I do not offhand think of a reason why the above code need to
deviate from that pattern.

Re: [GSoC][PATCH v2 2/4] submodule--helper: introduce for_each_submodule()

[Stefan Beller]

On Wed, Aug 23, 2017 at 12:13 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Prathamesh Chavan <pc44800@gmail.com> writes:
>
>> +typedef void (*submodule_list_func_t)(const struct cache_entry *list_item,
>> +                                   void *cb_data);
>> +
>>  static char *get_default_remote(void)
>>  {
>>       char *dest = NULL, *ret;
>> @@ -353,17 +356,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
>>       return 0;
>>  }
>>
>> -static void init_submodule(const char *path, const char *prefix, int quiet)
>> +static void for_each_submodule(const struct module_list *list,
>> +                            submodule_list_func_t fn, void *cb_data)
>
> In the output from
>
>         $ git grep for_each \*.h
>
> we find that the convention is that an interator over a group of X
> is for_each_X,

... which this is...

> the callback function that is given to for_each_X is
> of type each_X_fn.

So you suggest s/submodule_list_func_t/each_submodule_fn/

> An interator over a subset of group of X that
> has trait Y, for_each_Y_X() iterates and calls back a function of
> type each_X_fn (e.g. for_each_tag_ref() still calls each_ref_fn).

This reads as a suggestion for for_each_listed_submodule
as the name.

> I do not offhand think of a reason why the above code need to
> deviate from that pattern.

Re: [GSoC][PATCH v2 2/4] submodule--helper: introduce for_each_submodule()

[Junio C Hamano]

Stefan Beller <sbeller@google.com> writes:

> On Wed, Aug 23, 2017 at 12:13 PM, Junio C Hamano <gitster@pobox.com> wrote:
>> Prathamesh Chavan <pc44800@gmail.com> writes:
>>
>>> +typedef void (*submodule_list_func_t)(const struct cache_entry *list_item,
>>> +                                   void *cb_data);
>>> +
>>>  static char *get_default_remote(void)
>>>  {
>>>       char *dest = NULL, *ret;
>>> @@ -353,17 +356,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
>>>       return 0;
>>>  }
>>>
>>> -static void init_submodule(const char *path, const char *prefix, int quiet)
>>> +static void for_each_submodule(const struct module_list *list,
>>> +                            submodule_list_func_t fn, void *cb_data)
>>
>> In the output from
>>
>>         $ git grep for_each \*.h
>>
>> we find that the convention is that an interator over a group of X
>> is for_each_X,
>
> ... which this is...
>
>> the callback function that is given to for_each_X is
>> of type each_X_fn.
>
> So you suggest s/submodule_list_func_t/each_submodule_fn/

It's not _I_ suggest---the remainder of the codebase screams that
the above name is wrong ;-).  Didn't it for the mentors while they
were reading this code?

>> An interator over a subset of group of X that
>> has trait Y, for_each_Y_X() iterates and calls back a function of
>> type each_X_fn (e.g. for_each_tag_ref() still calls each_ref_fn).
>
> This reads as a suggestion for for_each_listed_submodule
> as the name.

If you need to have two ways to iterate over them, i.e. (1) over all
submodules and (2) over only the listed ones (whatever that means),
then yes, for_each_listed_submodule() would be a good name for the
latter which would be a complement to for_each_submodule() that is
the former.

>
>> I do not offhand think of a reason why the above code need to
>> deviate from that pattern.

[GSoC][PATCH v3 0/4] Incremental rewrite of git-submodules

[Prathamesh Chavan]

Changes in v3:

* The name of the iterator function for_each_submodule() was changed
  to the for_each_listed_submodule(), as the function fits the naming
  pattern for_each_Y_X(), as here we iterate over group of listed
  submodules (X) which are listed (Y) by the function module_list_compute()
* The name of the call back function type for the above pattern
  for_each_Y_X() is each_X_fn. Hence, this pattern was followed and
  the name of the call back function type for for_each_listed_submodule()
  was changed from submodule_list_func_t to each_submodule_fn.

As before you can find this series at: 
https://github.com/pratham-pc/git/commits/week-14-1

And its build report is available at: 
https://travis-ci.org/pratham-pc/git/builds/
Branch: week-14-1
Build #164

Prathamesh Chavan (4):
  submodule--helper: introduce get_submodule_displaypath()
  submodule--helper: introduce for_each_listed_submodule()
  submodule: port set_name_rev() from shell to C
  submodule: port submodule subcommand 'status' from shell to C

 builtin/submodule--helper.c | 294 ++++++++++++++++++++++++++++++++++++++++----
 git-submodule.sh            |  61 +--------
 2 files changed, 273 insertions(+), 82 deletions(-)

-- 
2.13.0

[GSoC][PATCH v3 1/4] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 38 +++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 84562ec83..e666f84ba 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -220,6 +220,28 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		int len = strlen(super_prefix);
+		const char *format = is_dir_sep(super_prefix[len - 1]) ? "%s%s" : "%s/%s";
+
+		return xstrfmt(format, super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -339,16 +361,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 	/* Only loads from .gitmodules, no overlay with .git/config */
 	gitmodules_config();
-
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -363,9 +376,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -373,7 +386,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -410,9 +422,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
-- 
2.13.0

[GSoC][PATCH v3 2/4] submodule--helper: introduce for_each_listed_submodule()

[Prathamesh Chavan]

Introduce function for_each_listed_submodule() and replace a loop
in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index e666f84ba..8cd81b144 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,9 @@
 #include "refs.h"
 #include "connect.h"
 
+typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
+				  void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -353,17 +356,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_listed_submodule(const struct module_list *list,
+				      each_submodule_fn fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+};
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const struct cache_entry *list_item, void *cb_data)
 {
+	struct init_cb *info = cb_data;
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	/* Only loads from .gitmodules, no overlay with .git/config */
-	gitmodules_config();
-	displaypath = get_submodule_displaypath(path, prefix);
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(&null_oid, list_item->name);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -375,7 +391,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 *
 	 * Set active flag for the submodule being initialized
 	 */
-	if (!is_submodule_active(the_repository, path)) {
+	if (!is_submodule_active(the_repository, list_item->name)) {
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 		strbuf_reset(&sb);
@@ -417,7 +433,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!info->quiet)
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -446,10 +462,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -474,8 +490,11 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	info.quiet = !!quiet;
+
+	gitmodules_config();
+	for_each_listed_submodule(&list, init_submodule, &info);
 
 	return 0;
 }
-- 
2.13.0

[GSoC][PATCH v3 3/4] submodule: port set_name_rev() from shell to C

[Prathamesh Chavan]

Function set_name_rev() is ported from git-submodule to the
submodule--helper builtin. The function compute_rev_name() generates the
value of the revision name as required.
The function get_rev_name() calls compute_rev_name() and receives the
revision name, and later handles its formating and printing.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            | 16 ++----------
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 8cd81b144..6ea6408c2 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -245,6 +245,68 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = {
+		NULL
+	};
+
+	static const char *describe_tags[] = {
+		"--tags", NULL
+	};
+
+	static const char *describe_contains[] = {
+		"--contains", NULL
+	};
+
+	static const char *describe_all_always[] = {
+		"--all", "--always", NULL
+	};
+
+	static const char **describe_argv[] = {
+		describe_bare, describe_tags, describe_contains,
+		describe_all_always, NULL
+	};
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0) && sb.len) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
+static int get_rev_name(int argc, const char **argv, const char *prefix)
+{
+	char *revname;
+	if (argc != 3)
+		die("get-rev-name only accepts two arguments: <path> <sha1>");
+
+	revname = compute_rev_name(argv[1], argv[2]);
+	if (revname && revname[0])
+		printf(" (%s)", revname);
+	printf("\n");
+
+	free(revname);
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -1243,6 +1305,7 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
+	{"get-rev-name", get_rev_name, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"push-check", push_check, 0},
diff --git a/git-submodule.sh b/git-submodule.sh
index e131760ee..91f043ec6 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -759,18 +759,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1042,14 +1030,14 @@ cmd_status()
 		fi
 		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
 		then
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say " $sha1 $displaypath$revname"
 		else
 			if test -z "$cached"
 			then
 				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
 			fi
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say "+$sha1 $displaypath$revname"
 		fi
 
-- 
2.13.0

[GSoC][PATCH v3 4/4] submodule: port submodule subcommand 'status' from shell to C

[Prathamesh Chavan]

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_listed_submodule() looping through the
list obtained.

Then for_each_listed_submodule() 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 <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 156 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  49 +-------------
 2 files changed, 157 insertions(+), 48 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 6ea6408c2..577494e31 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -561,6 +561,161 @@ 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,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (info->quiet)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+') {
+		struct argv_array get_rev_args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&get_rev_args, "get-rev-name",
+				 path, oid_to_hex(oid), NULL);
+		get_rev_name(get_rev_args.argc, get_rev_args.argv,
+			     info->prefix);
+
+		argv_array_clear(&get_rev_args);
+	} else {
+		printf("\n");
+	}
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+
+	if (!submodule_from_path(&null_oid, 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 (ce_stage(list_item)) {
+		print_status(info, 'U', list_item->name,
+			     &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, list_item->name)) {
+		print_status(info, '-', list_item->name, &list_item->oid,
+			     displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 list_item->name, NULL);
+
+	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
+			    info->prefix)) {
+		print_status(info, ' ', list_item->name, &list_item->oid,
+			     displaypath);
+	} else {
+		if (!info->cached) {
+			struct object_id oid;
+
+			if (head_ref_submodule(list_item->name,
+					       handle_submodule_head_ref, &oid))
+				die(_("could not resolve HEAD ref inside the"
+				      "submodule '%s'"), list_item->name);
+
+			print_status(info, '+', list_item->name, &oid,
+				     displaypath);
+		} else {
+			print_status(info, '+', list_item->name,
+				     &list_item->oid, 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:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+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_listed_submodule(&list, status_submodule, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1307,6 +1462,7 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"get-rev-name", get_rev_name, 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 91f043ec6..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=$(git submodule--helper get-rev-name "$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 get-rev-name "$sm_path" "$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

Re: [GSoC][PATCH v3 0/4] Incremental rewrite of git-submodules

[Junio C Hamano]

Thanks.  I'll try to queue these before I'll go offline.

Mentors may want to help the student further in adjusting the patch
series to the more recent codebase; unfortunately the area the GSoC
project touches is a bit fluid these days.  I resolved the conflicts
with nd/pune-in-worktree and bw/submodule-config-cleanup topics so
that the result would compile, but I am not sure if the resolution
is correct (e.g. there may be a new leak I introduced while doing
so).

Thanks.

Re: [GSoC][PATCH v3 0/4] Incremental rewrite of git-submodules

[Stefan Beller]

On Fri, Aug 25, 2017 at 11:51 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Thanks.  I'll try to queue these before I'll go offline.
>
> Mentors may want to help the student further in adjusting the patch
> series to the more recent codebase; unfortunately the area the GSoC
> project touches is a bit fluid these days.  I resolved the conflicts
> with nd/pune-in-worktree and bw/submodule-config-cleanup topics so
> that the result would compile, but I am not sure if the resolution
> is correct (e.g. there may be a new leak I introduced while doing
> so).
>
> Thanks.

Ok, noted.

Presumably I'll review your dirty merge then for this series?
(And later parts might go on top of the new dirty merge)

Re: [GSoC][PATCH v3 0/4] Incremental rewrite of git-submodules

[Junio C Hamano]

Stefan Beller <sbeller@google.com> writes:

> On Fri, Aug 25, 2017 at 11:51 AM, Junio C Hamano <gitster@pobox.com> wrote:
>> Thanks.  I'll try to queue these before I'll go offline.
>>
>> Mentors may want to help the student further in adjusting the patch
>> series to the more recent codebase; unfortunately the area the GSoC
>> project touches is a bit fluid these days.  I resolved the conflicts
>> with nd/pune-in-worktree and bw/submodule-config-cleanup topics so
>> that the result would compile, but I am not sure if the resolution
>> is correct (e.g. there may be a new leak I introduced while doing
>> so).
>>
>> Thanks.
>
> Ok, noted.
>
> Presumably I'll review your dirty merge then for this series?
> (And later parts might go on top of the new dirty merge)

In my mind, GSoC mentors are there to help the student improve as a
developer, more than they are to help improving the immediate output
of the student.  So in that sense, I was hoping that you'd teach how
to work well together with other developers, when one's topic has
interactions with topics by others.  Making sure an inevitable evil
merge is made correctly is of course needed for the current topic,
but a more important skill to learn is to avoid the need to ask an
evil merge to be made by the integrator in the first place.

Re: [GSoC][PATCH v3 0/4] Incremental rewrite of git-submodules

[Prathamesh Chavan]

On Sat, Aug 26, 2017 at 12:21 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Thanks.  I'll try to queue these before I'll go offline.
>
> Mentors may want to help the student further in adjusting the patch
> series to the more recent codebase; unfortunately the area the GSoC
> project touches is a bit fluid these days.  I resolved the conflicts
> with nd/pune-in-worktree and bw/submodule-config-cleanup topics so
> that the result would compile, but I am not sure if the resolution
> is correct (e.g. there may be a new leak I introduced while doing
> so).
>

Thanks.
I'll see the dirty merges and will resend the whole series after reviewing
the dirty merge and sending a new one with/without changes as required.

Thanks,
Prathamesh Chavan

[GSoC][PATCH v4 0/4] Incremental rewrite of git-submodules

[Prathamesh Chavan]

Changes in v4:
* The patches were adjusted to recent codebase.
  Also, the gitmodules_config() was call was removed
  from the functions module_init() and module_status()
  which was essential after the merge of the branch
  bw/submodule-config-cleanup.
  Since it was mentioned earlier, I even tried basing
  the patch series on the branch nd/prune-in-worktree.
  Conflicts occured while doing so, since the later
  branch is based on the master branch with the HEAD
  pointing to the commit:  The fourth batch post 2.14
  I think there won't be any conflicts, if that is changed.

As before you can find this series at: 
https://github.com/pratham-pc/git/commits/patch-series-1

And its build report is available at: 
https://travis-ci.org/pratham-pc/git/builds/
Branch: patch-series-1
Build #167

The above changes were based on master branch.

Another branch, similar to the above, was created, but was based
on the 'next' branch.

Complete build report of that is also available at:
https://travis-ci.org/pratham-pc/git/builds
Branch: patch-series-1-next
Build #168

The above changes are also push on github and are available at:
https://github.com/pratham-pc/git/commits/patch-series-1-next

Prathamesh Chavan (4):
  submodule--helper: introduce get_submodule_displaypath()
  submodule--helper: introduce for_each_listed_submodule()
  submodule: port set_name_rev() from shell to C
  submodule: port submodule subcommand 'status' from shell to C

 builtin/submodule--helper.c | 289 +++++++++++++++++++++++++++++++++++++++++---
 git-submodule.sh            |  61 +---------
 2 files changed, 271 insertions(+), 79 deletions(-)

-- 
2.13.0

[GSoC][PATCH v4 1/4] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 818fe74f0..e25854371 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -220,6 +220,28 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		int len = strlen(super_prefix);
+		const char *format = is_dir_sep(super_prefix[len - 1]) ? "%s%s" : "%s/%s";
+
+		return xstrfmt(format, super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -335,15 +357,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -358,9 +372,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -368,7 +382,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -405,9 +418,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
-- 
2.13.0

[GSoC][PATCH v4 2/4] submodule--helper: introduce for_each_listed_submodule()

[Prathamesh Chavan]

Introduce function for_each_listed_submodule() and replace a loop
in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index e25854371..ea99d8e39 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,9 @@
 #include "refs.h"
 #include "connect.h"
 
+typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
+				  void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -351,15 +354,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_listed_submodule(const struct module_list *list,
+				      each_submodule_fn fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+};
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const struct cache_entry *list_item, void *cb_data)
 {
+	struct init_cb *info = cb_data;
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	displaypath = get_submodule_displaypath(path, prefix);
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(&null_oid, list_item->name);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -371,7 +389,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 *
 	 * Set active flag for the submodule being initialized
 	 */
-	if (!is_submodule_active(the_repository, path)) {
+	if (!is_submodule_active(the_repository, list_item->name)) {
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 		strbuf_reset(&sb);
@@ -413,7 +431,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!info->quiet)
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -442,10 +460,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -470,8 +488,10 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	info.quiet = !!quiet;
+
+	for_each_listed_submodule(&list, init_submodule, &info);
 
 	return 0;
 }
-- 
2.13.0

[GSoC][PATCH v4 3/4] submodule: port set_name_rev() from shell to C

[Prathamesh Chavan]

Function set_name_rev() is ported from git-submodule to the
submodule--helper builtin. The function compute_rev_name() generates the
value of the revision name as required.
The function get_rev_name() calls compute_rev_name() and receives the
revision name, and later handles its formating and printing.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            | 16 ++----------
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index ea99d8e39..85df11129 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -245,6 +245,68 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = {
+		NULL
+	};
+
+	static const char *describe_tags[] = {
+		"--tags", NULL
+	};
+
+	static const char *describe_contains[] = {
+		"--contains", NULL
+	};
+
+	static const char *describe_all_always[] = {
+		"--all", "--always", NULL
+	};
+
+	static const char **describe_argv[] = {
+		describe_bare, describe_tags, describe_contains,
+		describe_all_always, NULL
+	};
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0) && sb.len) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
+static int get_rev_name(int argc, const char **argv, const char *prefix)
+{
+	char *revname;
+	if (argc != 3)
+		die("get-rev-name only accepts two arguments: <path> <sha1>");
+
+	revname = compute_rev_name(argv[1], argv[2]);
+	if (revname && revname[0])
+		printf(" (%s)", revname);
+	printf("\n");
+
+	free(revname);
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -1292,6 +1354,7 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
+	{"get-rev-name", get_rev_name, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"push-check", push_check, 0},
diff --git a/git-submodule.sh b/git-submodule.sh
index 66d1ae8ef..5211361c5 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -758,18 +758,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1041,14 +1029,14 @@ cmd_status()
 		fi
 		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
 		then
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say " $sha1 $displaypath$revname"
 		else
 			if test -z "$cached"
 			then
 				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
 			fi
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say "+$sha1 $displaypath$revname"
 		fi
 
-- 
2.13.0

[GSoC][PATCH v4 4/4] submodule: port submodule subcommand 'status' from shell to C

[Prathamesh Chavan]

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_listed_submodule() looping through the
list obtained.

Then for_each_listed_submodule() 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 <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 155 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  49 +-------------
 2 files changed, 156 insertions(+), 48 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 85df11129..abf5c126a 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -558,6 +558,160 @@ 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,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (info->quiet)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+') {
+		struct argv_array get_rev_args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&get_rev_args, "get-rev-name",
+				 path, oid_to_hex(oid), NULL);
+		get_rev_name(get_rev_args.argc, get_rev_args.argv,
+			     info->prefix);
+
+		argv_array_clear(&get_rev_args);
+	} else {
+		printf("\n");
+	}
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+
+	if (!submodule_from_path(&null_oid, 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 (ce_stage(list_item)) {
+		print_status(info, 'U', list_item->name,
+			     &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, list_item->name)) {
+		print_status(info, '-', list_item->name, &list_item->oid,
+			     displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 list_item->name, NULL);
+
+	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
+			    info->prefix)) {
+		print_status(info, ' ', list_item->name, &list_item->oid,
+			     displaypath);
+	} else {
+		if (!info->cached) {
+			struct object_id oid;
+
+			if (head_ref_submodule(list_item->name,
+					       handle_submodule_head_ref, &oid))
+				die(_("could not resolve HEAD ref inside the"
+				      "submodule '%s'"), list_item->name);
+
+			print_status(info, '+', list_item->name, &oid,
+				     displaypath);
+		} else {
+			print_status(info, '+', list_item->name,
+				     &list_item->oid, 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:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+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;
+
+	for_each_listed_submodule(&list, status_submodule, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1356,6 +1510,7 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"get-rev-name", get_rev_name, 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 5211361c5..156255a9e 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1004,54 +1004,7 @@ 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=$(git submodule--helper get-rev-name "$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 get-rev-name "$sm_path" "$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

[GSoC][PATCH v4 1/4] submodule--helper: introduce get_submodule_displaypath()

[Han-Wen Nienhuys]

LGTM with nits.

+static char *get_submodule_displaypath(const char *path, const char *prefix)

this could do with a comment

  /* the result should be freed by the caller. */

+	} else if (super_prefix) {
+		int len = strlen(super_prefix);
+		const char *format = is_dir_sep(super_prefix[len - 1]) ? "%s%s" : "%s/%s";

what if len == 0? The handling of '/' looks like a change from the original.

[GSoC][PATCH v4 3/4] submodule: port set_name_rev() from shell to C

[Han-Wen Nienhuys]

LGTM with nits

commit message:

"revision name, and later handles its formating and printing."

typo: formatting

+		if (!capture_command(&cp, &sb, 0) && sb.len) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}

you discard all output if these commands fail, so if the argument is a
not a submodule, or the other is not a sha1, it will just print
nothing without error message. Maybe that is OK, though? I don't see
documentation for these commands, so maybe this is not meant to be
usable?

[GSoC][PATCH v4 4/4] submodule: port submodule subcommand 'status' from shell to C

[Han-Wen Nienhuys]

+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule status [--quiet] [--cached] [--recursive] [<path>]"),
+		NULL

the manpage over here says

  git submodule [--quiet] status [--cached] [--recursive] [--] [<path>...]

ie. multiple path arguments. Should this usage string be tweaked?

+static void print_status(struct status_cb *info, char state, const char *path,
+			 const struct object_id *oid, const char *displaypath)
+{

could do with a comment. What are the options for the `state` char?

+	if (state == ' ' || state == '+') {
+		struct argv_array get_rev_args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&get_rev_args, "get-rev-name",
+				 path, oid_to_hex(oid), NULL);
+		get_rev_name(get_rev_args.argc, get_rev_args.argv,
+			     info->prefix);

since you're not really subprocessing, can't you simply have a

  do_print_rev_name(char *path, char *sha) {
     ..
     printf("\n");
  }

and call that directly? Or call compute_rev_name directly. Then you
don't have to do argv setup here.

Also, the name get_rev_name() is a little unfortunate, since it
doesn't return a name, but rather prints it. Maybe the functions
implementing helper commands could be named like:

  command_get_rev_name

or similar.

[PATCH v5 0/4] Incremental rewrite of git-submodules

[Prathamesh Chavan]

Changes in v5:
* in print_status() function, we now call compute_rev_name() directly
  instead of doing the argv setup and calling get_rev_name() function.
* Since we no longer use the helper function get_rev_name(), we have
  removed it from the code base after porting submodule subcommand
  'status'.
* function get_submodule_displaypath() has been modified, and now handles
  the case of super_prefix being non-null and of length zero.
* I have still kept the name of the function get_rev_name() unchanged,
  since in the function cmd_status(), it is used to get the value of
  the variable revname. And in the next commit since we do not require
  the function anymore, we reomve it from the code base.

As before you can find this series at: 
https://github.com/pratham-pc/git/commits/patch-series-1

And its build report is available at: 
https://travis-ci.org/pratham-pc/git/builds/
Branch: patch-series-1
Build #179

Thanks, Han-Wen Nienhuys for reviewing the previous patch series.

Prathamesh Chavan (4):
  submodule--helper: introduce get_submodule_displaypath()
  submodule--helper: introduce for_each_listed_submodule()
  submodule: port set_name_rev() from shell to C
  submodule: port submodule subcommand 'status' from shell to C

 builtin/submodule--helper.c | 265 ++++++++++++++++++++++++++++++++++++++++----
 git-submodule.sh            |  61 +---------
 2 files changed, 247 insertions(+), 79 deletions(-)

-- 
2.13.0

[PATCH v5 1/4] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 38 ++++++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 818fe74f0..d24ac9028 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -220,6 +220,29 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+/* the result should be freed by the caller. */
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		int len = strlen(super_prefix);
+		const char *format = (len > 0 && is_dir_sep(super_prefix[len - 1])) ? "%s%s" : "%s/%s";
+
+		return xstrfmt(format, super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -335,15 +358,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -358,9 +373,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -368,7 +383,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -405,9 +419,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
-- 
2.13.0

[PATCH v5 2/4] submodule--helper: introduce for_each_listed_submodule()

[Prathamesh Chavan]

Introduce function for_each_listed_submodule() and replace a loop
in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index d24ac9028..d12790b5c 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,9 @@
 #include "refs.h"
 #include "connect.h"
 
+typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
+				  void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -352,15 +355,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_listed_submodule(const struct module_list *list,
+				      each_submodule_fn fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+};
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const struct cache_entry *list_item, void *cb_data)
 {
+	struct init_cb *info = cb_data;
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	displaypath = get_submodule_displaypath(path, prefix);
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(&null_oid, list_item->name);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -372,7 +390,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 *
 	 * Set active flag for the submodule being initialized
 	 */
-	if (!is_submodule_active(the_repository, path)) {
+	if (!is_submodule_active(the_repository, list_item->name)) {
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 		strbuf_reset(&sb);
@@ -414,7 +432,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!info->quiet)
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -443,10 +461,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -471,8 +489,10 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	info.quiet = !!quiet;
+
+	for_each_listed_submodule(&list, init_submodule, &info);
 
 	return 0;
 }
-- 
2.13.0

[PATCH v5 3/4] submodule: port set_name_rev() from shell to C

[Prathamesh Chavan]

Function set_name_rev() is ported from git-submodule to the
submodule--helper builtin. The function compute_rev_name() generates the
value of the revision name as required.
The function get_rev_name() calls compute_rev_name() and receives the
revision name, and later handles its formatting and printing.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            | 16 ++----------
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index d12790b5c..7ca8e8153 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -246,6 +246,68 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = {
+		NULL
+	};
+
+	static const char *describe_tags[] = {
+		"--tags", NULL
+	};
+
+	static const char *describe_contains[] = {
+		"--contains", NULL
+	};
+
+	static const char *describe_all_always[] = {
+		"--all", "--always", NULL
+	};
+
+	static const char **describe_argv[] = {
+		describe_bare, describe_tags, describe_contains,
+		describe_all_always, NULL
+	};
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0) && sb.len) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
+static int get_rev_name(int argc, const char **argv, const char *prefix)
+{
+	char *revname;
+	if (argc != 3)
+		die("get-rev-name only accepts two arguments: <path> <sha1>");
+
+	revname = compute_rev_name(argv[1], argv[2]);
+	if (revname && revname[0])
+		printf(" (%s)", revname);
+	printf("\n");
+
+	free(revname);
+	return 0;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -1293,6 +1355,7 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
+	{"get-rev-name", get_rev_name, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"push-check", push_check, 0},
diff --git a/git-submodule.sh b/git-submodule.sh
index 66d1ae8ef..5211361c5 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -758,18 +758,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1041,14 +1029,14 @@ cmd_status()
 		fi
 		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
 		then
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say " $sha1 $displaypath$revname"
 		else
 			if test -z "$cached"
 			then
 				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
 			fi
-			set_name_rev "$sm_path" "$sha1"
+			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
 			say "+$sha1 $displaypath$revname"
 		fi
 
-- 
2.13.0

[PATCH v5 4/4] submodule: port submodule subcommand 'status' from shell to C

[Prathamesh Chavan]

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_listed_submodule() looping through the
list obtained.

Then for_each_listed_submodule() 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.

Helper function get_rev_name() removed after porting the above subcommand
as it is no longer used.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 162 +++++++++++++++++++++++++++++++++++++++-----
 git-submodule.sh            |  49 +-------------
 2 files changed, 147 insertions(+), 64 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 7ca8e8153..8876a4a08 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -293,21 +293,6 @@ static char *compute_rev_name(const char *sub_path, const char* object_id)
 	return NULL;
 }
 
-static int get_rev_name(int argc, const char **argv, const char *prefix)
-{
-	char *revname;
-	if (argc != 3)
-		die("get-rev-name only accepts two arguments: <path> <sha1>");
-
-	revname = compute_rev_name(argv[1], argv[2]);
-	if (revname && revname[0])
-		printf(" (%s)", revname);
-	printf("\n");
-
-	free(revname);
-	return 0;
-}
-
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -559,6 +544,151 @@ 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,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (info->quiet)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+')
+		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
+
+	printf("\n");
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+
+	if (!submodule_from_path(&null_oid, 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 (ce_stage(list_item)) {
+		print_status(info, 'U', list_item->name,
+			     &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, list_item->name)) {
+		print_status(info, '-', list_item->name, &list_item->oid,
+			     displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 list_item->name, NULL);
+
+	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
+			    info->prefix)) {
+		print_status(info, ' ', list_item->name, &list_item->oid,
+			     displaypath);
+	} else {
+		if (!info->cached) {
+			struct object_id oid;
+
+			if (refs_head_ref(get_submodule_ref_store(list_item->name), handle_submodule_head_ref, &oid))
+				die(_("could not resolve HEAD ref inside the"
+				      "submodule '%s'"), list_item->name);
+
+			print_status(info, '+', list_item->name, &oid,
+				     displaypath);
+		} else {
+			print_status(info, '+', list_item->name,
+				     &list_item->oid, 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:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+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;
+
+	for_each_listed_submodule(&list, status_submodule, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1355,8 +1485,8 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path, 0},
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
-	{"get-rev-name", get_rev_name, 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 5211361c5..156255a9e 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1004,54 +1004,7 @@ 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=$(git submodule--helper get-rev-name "$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 get-rev-name "$sm_path" "$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

Re: [PATCH v5 1/4] submodule--helper: introduce get_submodule_displaypath()

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> Introduce function get_submodule_displaypath() to replace the code
> occurring in submodule_init() for generating displaypath of the
> submodule with a call to it.
>
> This new function will also be used in other parts of the system
> in later patches.
>
> Mentored-by: Christian Couder <christian.couder@gmail.com>
> Mentored-by: Stefan Beller <sbeller@google.com>
> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
>  builtin/submodule--helper.c | 38 ++++++++++++++++++++++++++------------
>  1 file changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 818fe74f0..d24ac9028 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -220,6 +220,29 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
>  	return 0;
>  }
>  
> +/* the result should be freed by the caller. */
> +static char *get_submodule_displaypath(const char *path, const char *prefix)
> +{
> +	const char *super_prefix = get_super_prefix();
> +
> +	if (prefix && super_prefix) {
> +		BUG("cannot have prefix '%s' and superprefix '%s'",
> +		    prefix, super_prefix);
> +	} else if (prefix) {
> +		struct strbuf sb = STRBUF_INIT;
> +		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
> +		strbuf_release(&sb);
> +		return displaypath;
> +	} else if (super_prefix) {
> +		int len = strlen(super_prefix);
> +		const char *format = (len > 0 && is_dir_sep(super_prefix[len - 1])) ? "%s%s" : "%s/%s";
> +
> +		return xstrfmt(format, super_prefix, path);
> +	} else {
> +		return xstrdup(path);
> +	}
> +}

Looks like a fairly faithful rewrite of the original below, with a
reasonable clean-up (e.g. use of xstrfmt() instead of addf()).

One thing I noticed is that future callers of this function, unlike
init_submodule() which is its original caller, are allowed to have
super-prefix that does not end in a slash, because the helper
automatically supplies one when it is missing.

I am not sure the added leniency is desirable [*1*], but in any
case, the added leniency deserves a mention in the log message, I
would think.


[Footnote]

*1* Often it is harder to introduce bugs when the internal rules are
stricter, e.g. "prefix must end with slash", than when they are
looser, e.g. "prefix may or may not end with slash", because
allowing different codepaths to have the same thing in different
representations would hide bugs that is only uncovered when these
codepaths eventually meet (e.g. one codepath has a path with and the
other without trailing slash and they both think that is the
prefix---then they use strcmp() to see if they have the same prefix,
which would be a bug, which may not be noticed for a long time).

>  struct module_list {
>  	const struct cache_entry **entries;
>  	int alloc, nr;
> @@ -335,15 +358,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  	struct strbuf sb = STRBUF_INIT;
>  	char *upd = NULL, *url = NULL, *displaypath;
>  
> -	if (prefix && get_super_prefix())
> -		die("BUG: cannot have prefix and superprefix");
> -	else if (prefix)
> -		displaypath = xstrdup(relative_path(path, prefix, &sb));
> -	else if (get_super_prefix()) {
> -		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
> -		displaypath = strbuf_detach(&sb, NULL);
> -	} else
> -		displaypath = xstrdup(path);
> +	displaypath = get_submodule_displaypath(path, prefix);
>  
>  	sub = submodule_from_path(&null_oid, path);
>  
> @@ -358,9 +373,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  	 * Set active flag for the submodule being initialized
>  	 */
>  	if (!is_submodule_active(the_repository, path)) {
> -		strbuf_reset(&sb);
>  		strbuf_addf(&sb, "submodule.%s.active", sub->name);
>  		git_config_set_gently(sb.buf, "true");
> +		strbuf_reset(&sb);
>  	}
>  
>  	/*
> @@ -368,7 +383,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  	 * To look up the url in .git/config, we must not fall back to
>  	 * .gitmodules, so look it up directly.
>  	 */
> -	strbuf_reset(&sb);
>  	strbuf_addf(&sb, "submodule.%s.url", sub->name);
>  	if (git_config_get_string(sb.buf, &url)) {
>  		if (!sub->url)
> @@ -405,9 +419,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  				_("Submodule '%s' (%s) registered for path '%s'\n"),
>  				sub->name, url, displaypath);
>  	}
> +	strbuf_reset(&sb);
>  
>  	/* Copy "update" setting when it is not set yet */
> -	strbuf_reset(&sb);
>  	strbuf_addf(&sb, "submodule.%s.update", sub->name);
>  	if (git_config_get_string(sb.buf, &upd) &&
>  	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {

Re: [PATCH v5 2/4] submodule--helper: introduce for_each_listed_submodule()

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> Introduce function for_each_listed_submodule() and replace a loop
> in module_init() with a call to it.
>
> The new function will also be used in other parts of the
> system in later patches.
>
> Mentored-by: Christian Couder <christian.couder@gmail.com>
> Mentored-by: Stefan Beller <sbeller@google.com>
> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
>  builtin/submodule--helper.c | 36 ++++++++++++++++++++++++++++--------
>  1 file changed, 28 insertions(+), 8 deletions(-)

This looks more or less perfectly done, but I say this basing it on
an assumption that nobody ever would want to initialize a single
submodule without going through module_init() interface.

If there will be a caller that would have made a direct call to
init_submodule() if this patch did not exist, then I think this
patch is better done by keeping the external interface to the
init_submodule() function intact, and introducing an intermediate
helper init_submodule_cb() function that is to be used as the
callback used in for_each_listed_submodule() API.  In general, we
should make sure that these callback functions that take "void
*cb_data" parameters are called _only_ by these iterators that
defined the callback (in this case, for_each_listed_submodule())
and not other functions.

> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index d24ac9028..d12790b5c 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -14,6 +14,9 @@
>  #include "refs.h"
>  #include "connect.h"
>  
> +typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
> +				  void *cb_data);
> +
>  static char *get_default_remote(void)
>  {
>  	char *dest = NULL, *ret;
> @@ -352,15 +355,30 @@ static int module_list(int argc, const char **argv, const char *prefix)
>  	return 0;
>  }
>  
> -static void init_submodule(const char *path, const char *prefix, int quiet)
> +static void for_each_listed_submodule(const struct module_list *list,
> +				      each_submodule_fn fn, void *cb_data)
> +{
> +	int i;
> +	for (i = 0; i < list->nr; i++)
> +		fn(list->entries[i], cb_data);
> +}
> +
> +struct init_cb {
> +	const char *prefix;
> +	unsigned int quiet: 1;
> +};
> +#define INIT_CB_INIT { NULL, 0 }
> +
> +static void init_submodule(const struct cache_entry *list_item, void *cb_data)
>  {
> +	struct init_cb *info = cb_data;
>  	const struct submodule *sub;
>  	struct strbuf sb = STRBUF_INIT;
>  	char *upd = NULL, *url = NULL, *displaypath;
>  
> -	displaypath = get_submodule_displaypath(path, prefix);
> +	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
>  
> -	sub = submodule_from_path(&null_oid, path);
> +	sub = submodule_from_path(&null_oid, list_item->name);
>  
>  	if (!sub)
>  		die(_("No url found for submodule path '%s' in .gitmodules"),
> @@ -372,7 +390,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  	 *
>  	 * Set active flag for the submodule being initialized
>  	 */
> -	if (!is_submodule_active(the_repository, path)) {
> +	if (!is_submodule_active(the_repository, list_item->name)) {
>  		strbuf_addf(&sb, "submodule.%s.active", sub->name);
>  		git_config_set_gently(sb.buf, "true");
>  		strbuf_reset(&sb);
> @@ -414,7 +432,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  		if (git_config_set_gently(sb.buf, url))
>  			die(_("Failed to register url for submodule path '%s'"),
>  			    displaypath);
> -		if (!quiet)
> +		if (!info->quiet)
>  			fprintf(stderr,
>  				_("Submodule '%s' (%s) registered for path '%s'\n"),
>  				sub->name, url, displaypath);
> @@ -443,10 +461,10 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>  
>  static int module_init(int argc, const char **argv, const char *prefix)
>  {
> +	struct init_cb info = INIT_CB_INIT;
>  	struct pathspec pathspec;
>  	struct module_list list = MODULE_LIST_INIT;
>  	int quiet = 0;
> -	int i;
>  
>  	struct option module_init_options[] = {
>  		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
> @@ -471,8 +489,10 @@ static int module_init(int argc, const char **argv, const char *prefix)
>  	if (!argc && git_config_get_value_multi("submodule.active"))
>  		module_list_active(&list);
>  
> -	for (i = 0; i < list.nr; i++)
> -		init_submodule(list.entries[i]->name, prefix, quiet);
> +	info.prefix = prefix;
> +	info.quiet = !!quiet;
> +
> +	for_each_listed_submodule(&list, init_submodule, &info);
>  
>  	return 0;
>  }

Re: [PATCH v5 3/4] submodule: port set_name_rev() from shell to C

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> +static char *compute_rev_name(const char *sub_path, const char* object_id)
> +{
> +	struct strbuf sb = STRBUF_INIT;
> +	const char ***d;
> +
> +	static const char *describe_bare[] = {
> +		NULL
> +	};
> +...
> +	static const char **describe_argv[] = {
> +		describe_bare, describe_tags, describe_contains,
> +		describe_all_always, NULL
> +	};
> +
> +	for (d = describe_argv; *d; d++) {
> +		struct child_process cp = CHILD_PROCESS_INIT;
> +		prepare_submodule_repo_env(&cp.env_array);
> +		cp.dir = sub_path;
> +		cp.git_cmd = 1;
> +		cp.no_stderr = 1;
> +
> +		argv_array_push(&cp.args, "describe");
> +		argv_array_pushv(&cp.args, *d);
> +		argv_array_push(&cp.args, object_id);

Nicely done.

> +		if (!capture_command(&cp, &sb, 0) && sb.len) {

Observation: even if the command did not fail, if it returned an
empty string, then you would reject that result and loop on here.
This is different from the original scripted version, but it should
be OK.

> +			strbuf_strip_suffix(&sb, "\n");
> +			return strbuf_detach(&sb, NULL);
> +		}
> +	}
> +
> +	strbuf_release(&sb);
> +	return NULL;

Observation: and if you do not find any non-empty-string answer, you
return NULL.

> +}
> +
> +static int get_rev_name(int argc, const char **argv, const char *prefix)
> +{
> +	char *revname;
> +	if (argc != 3)
> +		die("get-rev-name only accepts two arguments: <path> <sha1>");
> +
> +	revname = compute_rev_name(argv[1], argv[2]);
> +	if (revname && revname[0])
> +		printf(" (%s)", revname);

So, while it is not wrong per-se, I do not think we need to check
revname[0] here.  The helper never returns a non-NULL pointer that
points at an empty string, right?

On the other hand, if we dropped the "&& sb.len" check in the helper
function to be more faithful to the original, then we must check
revname[0] for an empty string.

> +	printf("\n");
> +
> +	free(revname);
> +	return 0;
> +}
> +
>  struct module_list {
>  	const struct cache_entry **entries;
>  	int alloc, nr;
> @@ -1293,6 +1355,7 @@ static struct cmd_struct commands[] = {
>  	{"relative-path", resolve_relative_path, 0},
>  	{"resolve-relative-url", resolve_relative_url, 0},
>  	{"resolve-relative-url-test", resolve_relative_url_test, 0},
> +	{"get-rev-name", get_rev_name, 0},
>  	{"init", module_init, SUPPORT_SUPER_PREFIX},
>  	{"remote-branch", resolve_remote_submodule_branch, 0},
>  	{"push-check", push_check, 0},
> diff --git a/git-submodule.sh b/git-submodule.sh
> index 66d1ae8ef..5211361c5 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -758,18 +758,6 @@ cmd_update()
>  	}
>  }
>  
> -set_name_rev () {
> -	revname=$( (
> -		sanitize_submodule_env
> -		cd "$1" && {
> -			git describe "$2" 2>/dev/null ||
> -			git describe --tags "$2" 2>/dev/null ||
> -			git describe --contains "$2" 2>/dev/null ||
> -			git describe --all --always "$2"
> -		}
> -	) )
> -	test -z "$revname" || revname=" ($revname)"
> -}
>  #
>  # Show commit summary for submodules in index or working tree
>  #
> @@ -1041,14 +1029,14 @@ cmd_status()
>  		fi
>  		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
>  		then
> -			set_name_rev "$sm_path" "$sha1"
> +			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
>  			say " $sha1 $displaypath$revname"
>  		else
>  			if test -z "$cached"
>  			then
>  				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
>  			fi
> -			set_name_rev "$sm_path" "$sha1"
> +			revname=$(git submodule--helper get-rev-name "$sm_path" "$sha1")
>  			say "+$sha1 $displaypath$revname"
>  		fi

Re: [PATCH v5 3/4] submodule: port set_name_rev() from shell to C

[Junio C Hamano]

Junio C Hamano <gitster@pobox.com> writes:

> Nicely done.
>
>> +		if (!capture_command(&cp, &sb, 0) && sb.len) {
> ...
> So, while it is not wrong per-se, I do not think we need to check
> revname[0] here.  The helper never returns a non-NULL pointer that
> points at an empty string, right?
>
> On the other hand, if we dropped the "&& sb.len" check in the helper
> function to be more faithful to the original, then we must check
> revname[0] for an empty string.

Ah, ignore all of the above.  This will all be discarded in the next
step [4/4], as far as I can tell.  Perhaps we should drop this step
and get directly to it, making the result a three-patch series
instead, then, no?

Re: [PATCH v5 4/4] submodule: port submodule subcommand 'status' from shell to C

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> 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().

Well then it does not just aim to, but it does, doesn't it ;-)?

> @@ -559,6 +544,151 @@ 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,
> +			 const struct object_id *oid, const char *displaypath)
> +{
> +	if (info->quiet)
> +		return;
> +
> +	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
> +
> +	if (state == ' ' || state == '+')
> +		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
> +
> +	printf("\n");
> +}
> +
> +static int handle_submodule_head_ref(const char *refname,
> +				     const struct object_id *oid, int flags,
> +				     void *cb_data)
> +{
> +	struct object_id *output = cb_data;
> +	if (oid)
> +		oidcpy(output, oid);
> +
> +	return 0;
> +}

All of the above look sensible.

> +static void status_submodule(const struct cache_entry *list_item, void *cb_data)
> +{
> +	struct status_cb *info = cb_data;
> +	char *displaypath;
> +	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
> +
> +	if (!submodule_from_path(&null_oid, 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 (ce_stage(list_item)) {
> +		print_status(info, 'U', list_item->name,
> +			     &null_oid, displaypath);
> +		goto cleanup;
> +	}
> +
> +	if (!is_submodule_active(the_repository, list_item->name)) {
> +		print_status(info, '-', list_item->name, &list_item->oid,
> +			     displaypath);
> +		goto cleanup;
> +	}
> +
> +	argv_array_pushl(&diff_files_args, "diff-files",
> +			 "--ignore-submodules=dirty", "--quiet", "--",
> +			 list_item->name, NULL);
> +
> +	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
> +			    info->prefix)) {

Calling any cmd_foo() from places other than git.c, especially if it
is done more than once, is a source of bug.  I didn't check closely
if cmd_diff_files() currently has any of the potential problems, but
these functions are free to (1) modify global or file-scope static
variables, assuming that they will not be called again, leaving
these variables in a state different from the original and making
cmd_foo() unsuitable to be called twice, and (2) exit instead of
return at the end, among other things.

The functions in diff-lib.c (I think run_diff_files() for this
application) are designed to be called multiple times as library-ish
helpers; this caller should be using them instead.

> +		print_status(info, ' ', list_item->name, &list_item->oid,
> +			     displaypath);
> +	} else {
> +		if (!info->cached) {

By using "else if (!info->cached) {" here, you can reduce the
nesting level, perhaps?

> +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;
> +
> +	for_each_listed_submodule(&list, status_submodule, &info);
> +
> +	return 0;
> +}

The same comment as [2/4] on "init_submodule()?  don't you want
init_submodule_cb() instead?" applies to "status_submodule()".  I
suspect that in the future we would want more direct calls to show
the status of one single submodule, without indirectly controlling
what is chosen via the &list interface, and if that is the case,
you'd want the interface into the leaf level helper function to be a
more direct one that is not based on "void *cb_data", with a thin
wrapper around it that is to be used as the callback function by
for_each_listed_submodule().

Other than that, looks very cleanly done.

Thanks.

[PATCH v6 0/3] Incremental rewrite of git-submodules

[Prathamesh Chavan]

changes in v6:

* The function get_submodule_displaypath() was modified for the case
  when get_super_prefix() returns a non-null value. The condition to check
  if the super-prefix ends with a '/' is removed. To accomodate this change
  appropriate value of super_prefix is passed instead in the recursive calls
  of init_submodule() and status_submodule().

* To accomodate the possiblity of a direct call to the function
  init_submodule(), a callback function init_submodule_cb() is introduced
  which takes cache_entry and init_cb structures as input params, and
  calls init_submodule() with parameters which are more appropriate
  for a direct call of this function.

* Similar changes were even done for status_submodule(). But as it was
  observed that the number of params increased a lot due to flags
  like quiet, recursive, cached, etc, and keeping in mind the future
  subcommand's ported functions as well, a single unsigned int called
  cb_flags was introduced to store all of these flags, instead of having
  parameter for each one.

* Patches [3/4] and [4/4] from the previous series were merged as a single
  step.

* Call to function cmd_diff_files was avoided in the function status_submodule()
  and instead used the function run_diff_files() for the same purpose.

Since there were many changes the patches required, I took more time on
making these changes. Thank you, Junio for the last reviews. They
helped a lot for improving the patch series.

As before you can find this series at: 
https://github.com/pratham-pc/git/commits/patch-series-1

And its build report is available at: 
https://travis-ci.org/pratham-pc/git/builds/
Branch: patch-series-1
Build #184

Prathamesh Chavan (3):
  submodule--helper: introduce get_submodule_displaypath()
  submodule--helper: introduce for_each_listed_submodule()
  submodule: port submodule subcommand 'status' from shell to C

 builtin/submodule--helper.c | 281 +++++++++++++++++++++++++++++++++++++++++---
 git-submodule.sh            |  61 +---------
 2 files changed, 265 insertions(+), 77 deletions(-)

-- 
2.13.0

[PATCH v6 1/3] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 818fe74f0..cdae54426 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -220,6 +220,26 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+/* the result should be freed by the caller. */
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		return xstrfmt("%s%s", super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -335,15 +355,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -358,9 +370,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -368,7 +380,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -405,9 +416,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
-- 
2.13.0

[PATCH v6 2/3] submodule--helper: introduce for_each_listed_submodule()

[Prathamesh Chavan]

Introduce function for_each_listed_submodule() and replace a loop
in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index cdae54426..20a1ef868 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,11 @@
 #include "refs.h"
 #include "connect.h"
 
+#define CB_OPT_QUIET		(1<<0)
+
+typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
+				  void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -349,7 +354,22 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_listed_submodule(const struct module_list *list,
+				      each_submodule_fn fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int cb_flags;
+};
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const char *path, const char *prefix,
+			   unsigned int cb_flags)
 {
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
@@ -411,7 +431,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!(cb_flags & CB_OPT_QUIET))
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -438,12 +458,18 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	free(upd);
 }
 
+static void init_submodule_cb(const struct cache_entry *list_item, void *cb_data)
+{
+	struct init_cb *info = cb_data;
+	init_submodule(list_item->name, info->prefix, info->cb_flags);
+}
+
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -468,8 +494,11 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	if (quiet)
+		info.cb_flags |= CB_OPT_QUIET;
+
+	for_each_listed_submodule(&list, init_submodule_cb, &info);
 
 	return 0;
 }
-- 
2.13.0

[PATCH v6 3/3] submodule: port submodule subcommand 'status' from shell to C

[Prathamesh Chavan]

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
four functions: module_status(), submodule_status_cb(),
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_listed_submodule() looping through the
list obtained.

Then for_each_listed_submodule() calls submodule_status_cb() for each of
the submodule in its list. The function submodule_status_cb() calls
submodule_status() after passing appropriate arguments to the funciton.
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.

Function set_name_rev() is also ported from git-submodule to the
submodule--helper builtin function compute_rev_name(), which now
generates the value of the revision name as required.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 207 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  61 +------------
 2 files changed, 208 insertions(+), 60 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 20a1ef868..50d38fc20 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -13,8 +13,13 @@
 #include "remote.h"
 #include "refs.h"
 #include "connect.h"
+#include "revision.h"
+#include "diffcore.h"
+#include "diff.h"
 
 #define CB_OPT_QUIET		(1<<0)
+#define CB_OPT_CACHED		(1<<1)
+#define CB_OPT_RECURSIVE	(1<<2)
 
 typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
 				  void *cb_data);
@@ -245,6 +250,53 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = {
+		NULL
+	};
+
+	static const char *describe_tags[] = {
+		"--tags", NULL
+	};
+
+	static const char *describe_contains[] = {
+		"--contains", NULL
+	};
+
+	static const char *describe_all_always[] = {
+		"--all", "--always", NULL
+	};
+
+	static const char **describe_argv[] = {
+		describe_bare, describe_tags, describe_contains,
+		describe_all_always, NULL
+	};
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0)) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -503,6 +555,160 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+struct status_cb {
+	const char *prefix;
+	unsigned int cb_flags;
+};
+#define STATUS_CB_INIT { NULL, 0 }
+
+static void print_status(unsigned int flags, char state, const char *path,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (flags & CB_OPT_QUIET)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+')
+		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
+
+	printf("\n");
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const char *path, const struct object_id *ce_oid,
+			     unsigned int ce_flags, const char *prefix,
+			     unsigned int cb_flags)
+{
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+	struct rev_info rev;
+	int diff_files_result;
+
+	if (!submodule_from_path(&null_oid, path))
+		die(_("no submodule mapping found in .gitmodules for path '%s'"),
+		      path);
+
+	displaypath = get_submodule_displaypath(path, prefix);
+
+	if ((CE_STAGEMASK & ce_flags) >> CE_STAGESHIFT) {
+		print_status(cb_flags, 'U', path, &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, path)) {
+		print_status(cb_flags, '-', path, ce_oid, displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 path, NULL);
+
+	git_config(git_diff_basic_config, NULL);
+	init_revisions(&rev, prefix);
+	rev.abbrev = 0;
+	precompose_argv(diff_files_args.argc, diff_files_args.argv);
+	diff_files_args.argc = setup_revisions(diff_files_args.argc,
+					       diff_files_args.argv,
+					       &rev, NULL);
+	diff_files_result = run_diff_files(&rev, 0);
+
+	if (!diff_result_code(&rev.diffopt, diff_files_result)) {
+		print_status(cb_flags, ' ', path, ce_oid,
+			     displaypath);
+	} else if (!(cb_flags & CB_OPT_CACHED)) {
+		struct object_id oid;
+
+		if (refs_head_ref(get_submodule_ref_store(path),
+				  handle_submodule_head_ref, &oid))
+			die(_("could not resolve HEAD ref inside the"
+			      "submodule '%s'"), path);
+
+		print_status(cb_flags, '+', path, &oid, displaypath);
+	} else {
+		print_status(cb_flags, '+', path, ce_oid, displaypath);
+	}
+
+	if (cb_flags & CB_OPT_RECURSIVE) {
+		struct child_process cpr = CHILD_PROCESS_INIT;
+
+		cpr.git_cmd = 1;
+		cpr.dir = path;
+		prepare_submodule_repo_env(&cpr.env_array);
+
+		argv_array_push(&cpr.args, "--super-prefix");
+		argv_array_pushf(&cpr.args, "%s/", displaypath);
+		argv_array_pushl(&cpr.args, "submodule--helper", "status",
+				 "--recursive", NULL);
+
+		if (cb_flags & CB_OPT_CACHED)
+			argv_array_push(&cpr.args, "--cached");
+
+		if (cb_flags & CB_OPT_QUIET)
+			argv_array_push(&cpr.args, "--quiet");
+
+		if (run_command(&cpr))
+			die(_("failed to recurse into submodule '%s'"), path);
+	}
+
+cleanup:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+static void status_submodule_cb(const struct cache_entry *list_item,
+				void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	status_submodule(list_item->name, &list_item->oid, list_item->ce_flags,
+			 info->prefix, info->cb_flags);
+}
+
+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;
+
+	struct option module_status_options[] = {
+		OPT__QUIET(&quiet, N_("Suppress submodule status output")),
+		OPT_BIT(0, "cached", &info.cb_flags, N_("Use commit stored in the index instead of the one stored in the submodule HEAD"), CB_OPT_CACHED),
+		OPT_BIT(0, "recursive", &info.cb_flags, N_("recurse into nested submodules"), CB_OPT_RECURSIVE),
+		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;
+	if (quiet)
+		info.cb_flags |= CB_OPT_QUIET;
+
+	for_each_listed_submodule(&list, status_submodule_cb, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1300,6 +1506,7 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 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 66d1ae8ef..156255a9e 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -758,18 +758,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1016,54 +1004,7 @@ 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
-			set_name_rev "$sm_path" "$sha1"
-			say " $sha1 $displaypath$revname"
-		else
-			if test -z "$cached"
-			then
-				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
-			fi
-			set_name_rev "$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

Re: [PATCH v6 0/3] Incremental rewrite of git-submodules

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> * The function get_submodule_displaypath() was modified for the case
>   when get_super_prefix() returns a non-null value. The condition to check
>   if the super-prefix ends with a '/' is removed. To accomodate this change
>   appropriate value of super_prefix is passed instead in the recursive calls
>   of init_submodule() and status_submodule().

OK.

> * To accomodate the possiblity of a direct call to the function
>   init_submodule(), a callback function init_submodule_cb() is introduced
>   which takes cache_entry and init_cb structures as input params, and
>   calls init_submodule() with parameters which are more appropriate
>   for a direct call of this function.

OK.

> * Similar changes were even done for status_submodule(). But as it was
>   observed that the number of params increased a lot due to flags
>   like quiet, recursive, cached, etc, and keeping in mind the future
>   subcommand's ported functions as well, a single unsigned int called
>   cb_flags was introduced to store all of these flags, instead of having
>   parameter for each one.

Use of a flag word instead of many bit parameter is a very good
idea.  I do not think it is brilliant to call a field in a structure
that is used as an interface to the callback interface cb_flags,
though, especially when it is already clear that it is about the
callback from the name the structure.  Just name them "flags".

I may or may not leave more detailed comments on individual patches.

Thanks.

Re: [PATCH v6 1/3] submodule--helper: introduce get_submodule_displaypath()

[Junio C Hamano]

This step looks good to me.  Thanks.

Re: [PATCH v6 2/3] submodule--helper: introduce for_each_listed_submodule()

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> Introduce function for_each_listed_submodule() and replace a loop
> in module_init() with a call to it.
>
> The new function will also be used in other parts of the
> system in later patches.
>
> Mentored-by: Christian Couder <christian.couder@gmail.com>
> Mentored-by: Stefan Beller <sbeller@google.com>
> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
>  builtin/submodule--helper.c | 39 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 34 insertions(+), 5 deletions(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index cdae54426..20a1ef868 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -14,6 +14,11 @@
>  #include "refs.h"
>  #include "connect.h"
>  
> +#define CB_OPT_QUIET		(1<<0)

Is the purpose of this bit to make the callback quiet?  I do not
think so.  Is there a reason why we cannot call it just OPT_QUIET or
something instead?

When the set of functions that pay attention to these flags include
both ones that are callable for a single submodule and ones meant as
callbacks for for-each interface, having to flip bit whose name
screams "CallBack!" in a caller of a single-short version feels very
wrong.

"make style" tells me to format the above like so:

	#define OPT_QUIET (1 << 0)

and I think I agree.

> @@ -349,7 +354,22 @@ static int module_list(int argc, const char **argv, const char *prefix)
>  	return 0;
>  }
>  
> -static void init_submodule(const char *path, const char *prefix, int quiet)
> +static void for_each_listed_submodule(const struct module_list *list,
> +				      each_submodule_fn fn, void *cb_data)
> +{
> +	int i;
> +	for (i = 0; i < list->nr; i++)
> +		fn(list->entries[i], cb_data);
> +}

Good.

> +struct init_cb {

I take it is a short-hand for "submodule init callback"?  As long as
the name stays inside this file, I think we are OK.

> +	const char *prefix;
> +	unsigned int cb_flags;

Call this just "flags"; call-back ness is plenty clear from the fact
that it lives in a structure meant as a callback interface already.

> +};

Blank line here?

> +#define INIT_CB_INIT { NULL, 0 }
> +
> +static void init_submodule(const char *path, const char *prefix,
> +			   unsigned int cb_flags)

Call this also "flags"; a direct caller of this function that wants
to initialize a single submodule without going thru the for-each
callback interface would not be passing "callback flags"--they are
just passing a set of flags.

Re: [PATCH v6 3/3] submodule: port submodule subcommand 'status' from shell to C

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

>  
>  #define CB_OPT_QUIET		(1<<0)
> +#define CB_OPT_CACHED		(1<<1)
> +#define CB_OPT_RECURSIVE	(1<<2)

Same comments on both naming and formatting.

> @@ -245,6 +250,53 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
>  	}
>  }
>  
> +static char *compute_rev_name(const char *sub_path, const char* object_id)
> +{
> +	struct strbuf sb = STRBUF_INIT;
> +	const char ***d;
> +
> +	static const char *describe_bare[] = {
> +		NULL
> +	};
> +
> +	static const char *describe_tags[] = {
> +		"--tags", NULL
> +	};
> +
> +	static const char *describe_contains[] = {
> +		"--contains", NULL
> +	};
> +
> +	static const char *describe_all_always[] = {
> +		"--all", "--always", NULL
> +	};
> +
> +	static const char **describe_argv[] = {
> +		describe_bare, describe_tags, describe_contains,
> +		describe_all_always, NULL
> +	};

"make style" seems to suggest a lot more compact version to be used
for the above, and I tend to agree with its diagnosis.

> @@ -503,6 +555,160 @@ static int module_init(int argc, const char **argv, const char *prefix)
>  	return 0;
>  }
>  
> +struct status_cb {
> +	const char *prefix;
> +	unsigned int cb_flags;
> +};
> +#define STATUS_CB_INIT { NULL, 0 }

Same three comments as the previous "init_cb" patch apply.

> +	argv_array_pushl(&diff_files_args, "diff-files",
> +			 "--ignore-submodules=dirty", "--quiet", "--",
> +			 path, NULL);
> +
> +	git_config(git_diff_basic_config, NULL);

Should this be called every time?  The config file is not changing,
no?

> +	init_revisions(&rev, prefix);
> +	rev.abbrev = 0;

This part looks OK.

> +	precompose_argv(diff_files_args.argc, diff_files_args.argv);

I do not think this is correct.  We certainly did not get the path
argument (i.e. args.argv) from the command line of macOS X box and
the correction for UTF-8 canonicalization should not be necessary.
Even if we did get path from the command line, I think the UTF-8
correction should have been done for us for any command (like "git
submodule--helper") that uses parse-optoins API already.

Just dropping the line should be sufficient to correct this, I think.

The remainder of the patch looked more-or-less OK, but I'd revisit
it later to make sure.

Thanks.

[PATCH v7 0/3] Incremental rewrite of git-submodules

[Prathamesh Chavan]

Changes in v7:

* Instead of using cb_flags in the callback data's struct, 'flags' is used.

* Similar changes were applied to the CB_OPT_QUIET and other bits.

* The function compute_rev_name() was formatted in accordance with the "make
  style", into a compact version.

* Call to precompose_argv() in the function status_submodule() was dropped
  as the call was unnecessary.

As before you can find this series at: 
https://github.com/pratham-pc/git/commits/patch-series-1

And its build report is available at: 
https://travis-ci.org/pratham-pc/git/builds/
Branch: patch-series-1
Build #190

The above changes were based on master branch.

Another branch, similar to the above, was created, but was based
on the 'next' branch.
Complete build report of that is also available at:
https://travis-ci.org/pratham-pc/git/builds
Branch: patch-series-1-next
Build #189
The above changes are also push on github and are available at:
https://github.com/pratham-pc/git/commits/patch-series-1-next

Prathamesh Chavan (3):
  submodule--helper: introduce get_submodule_displaypath()
  submodule--helper: introduce for_each_listed_submodule()
  submodule: port submodule subcommand 'status' from shell to C

 builtin/submodule--helper.c | 273 +++++++++++++++++++++++++++++++++++++++++---
 git-submodule.sh            |  61 +---------
 2 files changed, 257 insertions(+), 77 deletions(-)

-- 
2.14.2

[PATCH v7 1/3] submodule--helper: introduce get_submodule_displaypath()

[Prathamesh Chavan]

Introduce function get_submodule_displaypath() to replace the code
occurring in submodule_init() for generating displaypath of the
submodule with a call to it.

This new function will also be used in other parts of the system
in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 06ed02f99..56c1c52e2 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -219,6 +219,26 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
 	return 0;
 }
 
+/* the result should be freed by the caller. */
+static char *get_submodule_displaypath(const char *path, const char *prefix)
+{
+	const char *super_prefix = get_super_prefix();
+
+	if (prefix && super_prefix) {
+		BUG("cannot have prefix '%s' and superprefix '%s'",
+		    prefix, super_prefix);
+	} else if (prefix) {
+		struct strbuf sb = STRBUF_INIT;
+		char *displaypath = xstrdup(relative_path(path, prefix, &sb));
+		strbuf_release(&sb);
+		return displaypath;
+	} else if (super_prefix) {
+		return xstrfmt("%s%s", super_prefix, path);
+	} else {
+		return xstrdup(path);
+	}
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -334,15 +354,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	struct strbuf sb = STRBUF_INIT;
 	char *upd = NULL, *url = NULL, *displaypath;
 
-	if (prefix && get_super_prefix())
-		die("BUG: cannot have prefix and superprefix");
-	else if (prefix)
-		displaypath = xstrdup(relative_path(path, prefix, &sb));
-	else if (get_super_prefix()) {
-		strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
-		displaypath = strbuf_detach(&sb, NULL);
-	} else
-		displaypath = xstrdup(path);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(&null_oid, path);
 
@@ -357,9 +369,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * Set active flag for the submodule being initialized
 	 */
 	if (!is_submodule_active(the_repository, path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
+		strbuf_reset(&sb);
 	}
 
 	/*
@@ -367,7 +379,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
 	 */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
 		if (!sub->url)
@@ -404,9 +415,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
 	}
+	strbuf_reset(&sb);
 
 	/* Copy "update" setting when it is not set yet */
-	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
 	if (git_config_get_string(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
-- 
2.14.2

[PATCH v7 2/3] submodule--helper: introduce for_each_listed_submodule()

[Prathamesh Chavan]

Introduce function for_each_listed_submodule() and replace a loop
in module_init() with a call to it.

The new function will also be used in other parts of the
system in later patches.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 40 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 56c1c52e2..29e3fde16 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -14,6 +14,11 @@
 #include "refs.h"
 #include "connect.h"
 
+#define OPT_QUIET (1 << 0)
+
+typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
+				  void *cb_data);
+
 static char *get_default_remote(void)
 {
 	char *dest = NULL, *ret;
@@ -348,7 +353,23 @@ static int module_list(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void init_submodule(const char *path, const char *prefix, int quiet)
+static void for_each_listed_submodule(const struct module_list *list,
+				      each_submodule_fn fn, void *cb_data)
+{
+	int i;
+	for (i = 0; i < list->nr; i++)
+		fn(list->entries[i], cb_data);
+}
+
+struct init_cb {
+	const char *prefix;
+	unsigned int flags;
+};
+
+#define INIT_CB_INIT { NULL, 0 }
+
+static void init_submodule(const char *path, const char *prefix,
+			   unsigned int flags)
 {
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
@@ -410,7 +431,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 		if (git_config_set_gently(sb.buf, url))
 			die(_("Failed to register url for submodule path '%s'"),
 			    displaypath);
-		if (!quiet)
+		if (!(flags & OPT_QUIET))
 			fprintf(stderr,
 				_("Submodule '%s' (%s) registered for path '%s'\n"),
 				sub->name, url, displaypath);
@@ -437,12 +458,18 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	free(upd);
 }
 
+static void init_submodule_cb(const struct cache_entry *list_item, void *cb_data)
+{
+	struct init_cb *info = cb_data;
+	init_submodule(list_item->name, info->prefix, info->flags);
+}
+
 static int module_init(int argc, const char **argv, const char *prefix)
 {
+	struct init_cb info = INIT_CB_INIT;
 	struct pathspec pathspec;
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-	int i;
 
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
@@ -467,8 +494,11 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	if (!argc && git_config_get_value_multi("submodule.active"))
 		module_list_active(&list);
 
-	for (i = 0; i < list.nr; i++)
-		init_submodule(list.entries[i]->name, prefix, quiet);
+	info.prefix = prefix;
+	if (quiet)
+		info.flags |= OPT_QUIET;
+
+	for_each_listed_submodule(&list, init_submodule_cb, &info);
 
 	return 0;
 }
-- 
2.14.2

[PATCH v7 3/3] submodule: port submodule subcommand 'status' from shell to C

[Prathamesh Chavan]

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
four functions: module_status(), submodule_status_cb(),
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_listed_submodule() looping through the
list obtained.

Then for_each_listed_submodule() calls submodule_status_cb() for each of
the submodule in its list. The function submodule_status_cb() calls
submodule_status() after passing appropriate arguments to the funciton.
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.

Function set_name_rev() is also ported from git-submodule to the
submodule--helper builtin function compute_rev_name(), which now
generates the value of the revision name as required.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
---
 builtin/submodule--helper.c | 198 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  61 +-------------
 2 files changed, 199 insertions(+), 60 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 29e3fde16..d366e8e7b 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -13,8 +13,13 @@
 #include "remote.h"
 #include "refs.h"
 #include "connect.h"
+#include "revision.h"
+#include "diffcore.h"
+#include "diff.h"
 
 #define OPT_QUIET (1 << 0)
+#define OPT_CACHED (1 << 1)
+#define OPT_RECURSIVE (1 << 2)
 
 typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
 				  void *cb_data);
@@ -244,6 +249,44 @@ static char *get_submodule_displaypath(const char *path, const char *prefix)
 	}
 }
 
+static char *compute_rev_name(const char *sub_path, const char* object_id)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char ***d;
+
+	static const char *describe_bare[] = { NULL };
+
+	static const char *describe_tags[] = { "--tags", NULL };
+
+	static const char *describe_contains[] = { "--contains", NULL };
+
+	static const char *describe_all_always[] = { "--all", "--always", NULL };
+
+	static const char **describe_argv[] = { describe_bare, describe_tags,
+						describe_contains,
+						describe_all_always, NULL };
+
+	for (d = describe_argv; *d; d++) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		prepare_submodule_repo_env(&cp.env_array);
+		cp.dir = sub_path;
+		cp.git_cmd = 1;
+		cp.no_stderr = 1;
+
+		argv_array_push(&cp.args, "describe");
+		argv_array_pushv(&cp.args, *d);
+		argv_array_push(&cp.args, object_id);
+
+		if (!capture_command(&cp, &sb, 0)) {
+			strbuf_strip_suffix(&sb, "\n");
+			return strbuf_detach(&sb, NULL);
+		}
+	}
+
+	strbuf_release(&sb);
+	return NULL;
+}
+
 struct module_list {
 	const struct cache_entry **entries;
 	int alloc, nr;
@@ -503,6 +546,160 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+struct status_cb {
+	const char *prefix;
+	unsigned int flags;
+};
+
+#define STATUS_CB_INIT { NULL, 0 }
+
+static void print_status(unsigned int flags, char state, const char *path,
+			 const struct object_id *oid, const char *displaypath)
+{
+	if (flags & OPT_QUIET)
+		return;
+
+	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
+
+	if (state == ' ' || state == '+')
+		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
+
+	printf("\n");
+}
+
+static int handle_submodule_head_ref(const char *refname,
+				     const struct object_id *oid, int flags,
+				     void *cb_data)
+{
+	struct object_id *output = cb_data;
+	if (oid)
+		oidcpy(output, oid);
+
+	return 0;
+}
+
+static void status_submodule(const char *path, const struct object_id *ce_oid,
+			     unsigned int ce_flags, const char *prefix,
+			     unsigned int flags)
+{
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+	struct rev_info rev;
+	int diff_files_result;
+
+	if (!submodule_from_path(&null_oid, path))
+		die(_("no submodule mapping found in .gitmodules for path '%s'"),
+		      path);
+
+	displaypath = get_submodule_displaypath(path, prefix);
+
+	if ((CE_STAGEMASK & ce_flags) >> CE_STAGESHIFT) {
+		print_status(flags, 'U', path, &null_oid, displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_active(the_repository, path)) {
+		print_status(flags, '-', path, ce_oid, displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 path, NULL);
+
+	git_config(git_diff_basic_config, NULL);
+	init_revisions(&rev, prefix);
+	rev.abbrev = 0;
+	diff_files_args.argc = setup_revisions(diff_files_args.argc,
+					       diff_files_args.argv,
+					       &rev, NULL);
+	diff_files_result = run_diff_files(&rev, 0);
+
+	if (!diff_result_code(&rev.diffopt, diff_files_result)) {
+		print_status(flags, ' ', path, ce_oid,
+			     displaypath);
+	} else if (!(flags & OPT_CACHED)) {
+		struct object_id oid;
+
+		if (refs_head_ref(get_submodule_ref_store(path),
+				  handle_submodule_head_ref, &oid))
+			die(_("could not resolve HEAD ref inside the"
+			      "submodule '%s'"), path);
+
+		print_status(flags, '+', path, &oid, displaypath);
+	} else {
+		print_status(flags, '+', path, ce_oid, displaypath);
+	}
+
+	if (flags & OPT_RECURSIVE) {
+		struct child_process cpr = CHILD_PROCESS_INIT;
+
+		cpr.git_cmd = 1;
+		cpr.dir = path;
+		prepare_submodule_repo_env(&cpr.env_array);
+
+		argv_array_push(&cpr.args, "--super-prefix");
+		argv_array_pushf(&cpr.args, "%s/", displaypath);
+		argv_array_pushl(&cpr.args, "submodule--helper", "status",
+				 "--recursive", NULL);
+
+		if (flags & OPT_CACHED)
+			argv_array_push(&cpr.args, "--cached");
+
+		if (flags & OPT_QUIET)
+			argv_array_push(&cpr.args, "--quiet");
+
+		if (run_command(&cpr))
+			die(_("failed to recurse into submodule '%s'"), path);
+	}
+
+cleanup:
+	argv_array_clear(&diff_files_args);
+	free(displaypath);
+}
+
+static void status_submodule_cb(const struct cache_entry *list_item,
+				void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	status_submodule(list_item->name, &list_item->oid, list_item->ce_flags,
+			 info->prefix, info->flags);
+}
+
+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;
+
+	struct option module_status_options[] = {
+		OPT__QUIET(&quiet, N_("Suppress submodule status output")),
+		OPT_BIT(0, "cached", &info.flags, N_("Use commit stored in the index instead of the one stored in the submodule HEAD"), OPT_CACHED),
+		OPT_BIT(0, "recursive", &info.flags, N_("recurse into nested submodules"), OPT_RECURSIVE),
+		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;
+	if (quiet)
+		info.flags |= OPT_QUIET;
+
+	for_each_listed_submodule(&list, status_submodule_cb, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1300,6 +1497,7 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 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 66d1ae8ef..156255a9e 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -758,18 +758,6 @@ cmd_update()
 	}
 }
 
-set_name_rev () {
-	revname=$( (
-		sanitize_submodule_env
-		cd "$1" && {
-			git describe "$2" 2>/dev/null ||
-			git describe --tags "$2" 2>/dev/null ||
-			git describe --contains "$2" 2>/dev/null ||
-			git describe --all --always "$2"
-		}
-	) )
-	test -z "$revname" || revname=" ($revname)"
-}
 #
 # Show commit summary for submodules in index or working tree
 #
@@ -1016,54 +1004,7 @@ 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
-			set_name_rev "$sm_path" "$sha1"
-			say " $sha1 $displaypath$revname"
-		else
-			if test -z "$cached"
-			then
-				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
-			fi
-			set_name_rev "$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
-- 
2.14.2

Re: [PATCH v7 1/3] submodule--helper: introduce get_submodule_displaypath()

[Eric Sunshine]

I didn't find a URL in the cover letter pointing at previous
iterations of this patch series and related discussions, so forgive me
if comments below merely repeat what was said earlier...

On Fri, Oct 6, 2017 at 9:24 AM, Prathamesh Chavan <pc44800@gmail.com> wrote:
> Introduce function get_submodule_displaypath() to replace the code
> occurring in submodule_init() for generating displaypath of the
> submodule with a call to it.
>
> This new function will also be used in other parts of the system
> in later patches.
>
> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> @@ -219,6 +219,26 @@ static int resolve_relative_url_test(int argc, const char **argv, const char *pr
> +/* the result should be freed by the caller. */
> +static char *get_submodule_displaypath(const char *path, const char *prefix)
> +{
> +       const char *super_prefix = get_super_prefix();
> +
> +       if (prefix && super_prefix) {
> +               BUG("cannot have prefix '%s' and superprefix '%s'",
> +                   prefix, super_prefix);
> +       } else if (prefix) {
> +               struct strbuf sb = STRBUF_INIT;
> +               char *displaypath = xstrdup(relative_path(path, prefix, &sb));
> +               strbuf_release(&sb);
> +               return displaypath;
> +       } else if (super_prefix) {
> +               return xstrfmt("%s%s", super_prefix, path);
> +       } else {
> +               return xstrdup(path);
> +       }
> +}

At first glance, this appears to be a simple code-movement patch which
shouldn't require deep inspection by a reviewer, however, upon closer
examination, it turns out that it is doing rather more than that,
which increases reviewer burden, especially since these additional
changes are not mentioned in the commit message. At a minimum, it
includes these changes:

* factors out calls to get_super_prefix()
* adds extra context to the "BUG" message
* changes die("BUG...") to BUG(...)
* allocates/releases a strbuf
* changes assignments to returns

The final two are obvious necessary (or clarifying) changes which a
reviewer would expect to see in a patch which factors code out to its
own function; the others not so.

This isn't to say that the other changes are not reasonable -- they
are -- but if one of your goals is to make the patches easy for
reviewers to digest, then you should make the changes as obvious as
possible for reviewers to spot. One way would be to mention in the
commit message that you're taking the opportunity to also make these
particular cleanups to the code. A more common approach is to place
the various cleanups in preparatory patches before this one, with one
cleanup per patch. I'd prefer to see the latter (if my opinion carries
any weight).

More below...

> @@ -334,15 +354,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>         struct strbuf sb = STRBUF_INIT;
>         char *upd = NULL, *url = NULL, *displaypath;
>
> -       if (prefix && get_super_prefix())
> -               die("BUG: cannot have prefix and superprefix");
> -       else if (prefix)
> -               displaypath = xstrdup(relative_path(path, prefix, &sb));
> -       else if (get_super_prefix()) {
> -               strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
> -               displaypath = strbuf_detach(&sb, NULL);
> -       } else
> -               displaypath = xstrdup(path);
> +       displaypath = get_submodule_displaypath(path, prefix);
>
>         sub = submodule_from_path(&null_oid, path);
>
> @@ -357,9 +369,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>          * Set active flag for the submodule being initialized
>          */
>         if (!is_submodule_active(the_repository, path)) {
> -               strbuf_reset(&sb);
>                 strbuf_addf(&sb, "submodule.%s.active", sub->name);
>                 git_config_set_gently(sb.buf, "true");
> +               strbuf_reset(&sb);

This strbuf_reset() movement, and those below, are pretty much just
"noise" changes. They add extra burden to the review process without
really improving the code. The reason they add to reviewer burden is
that they do not seem to be related to the intention stated in the
commit message, so the reviewer must spend extra time trying to
understand their purpose and correctness.

More serious, though, is that these strbuf_reset() movements may
actually increase the burden on someone changing the code in the
future. Presumably, your reason for making these changes is that you
reviewed the code after factoring out the get_submodule_displaypath()
logic and discovered that the strbuf was no longer touched before this
point, therefore resetting it before strbuf_addf() is unnecessary.
While this may be true today, it may not be so in the future. If
someone comes along and adds code above this point which does touch
the strbuf, then these code movements either need to be reverted by
that person (more noise) or that person needs to remember to add a
strbuf_reset() at the end of the new code.

Moreover, it's somewhat easier to reason about the strbuf_reset()'s
and the corresponding strbuf_addf()'s when they are kept together, as
in the original code, so, for that reason alone, one could argue that
moving the strbuf_reset()'s does not really improve the code.

I'd suggest dropping these changes in the re-roll.

>         }
>
>         /*
> @@ -367,7 +379,6 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>          * To look up the url in .git/config, we must not fall back to
>          * .gitmodules, so look it up directly.
>          */
> -       strbuf_reset(&sb);
>         strbuf_addf(&sb, "submodule.%s.url", sub->name);
>         if (git_config_get_string(sb.buf, &url)) {
>                 if (!sub->url)
> @@ -404,9 +415,9 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>                                 _("Submodule '%s' (%s) registered for path '%s'\n"),
>                                 sub->name, url, displaypath);
>         }
> +       strbuf_reset(&sb);
>
>         /* Copy "update" setting when it is not set yet */
> -       strbuf_reset(&sb);
>         strbuf_addf(&sb, "submodule.%s.update", sub->name);
>         if (git_config_get_string(sb.buf, &upd) &&
>             sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
> --
> 2.14.2

Re: [PATCH v7 2/3] submodule--helper: introduce for_each_listed_submodule()

[Eric Sunshine]

Same disclaimer as in my review of patch 1/3: I didn't see a URL in
the cover letter pointing at discussions of earlier iterations, so
below comments may be at odds with what went on previously...

On Fri, Oct 6, 2017 at 9:24 AM, Prathamesh Chavan <pc44800@gmail.com> wrote:
> Introduce function for_each_listed_submodule() and replace a loop
> in module_init() with a call to it.
>
> The new function will also be used in other parts of the
> system in later patches.
>
> Signed-off-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> @@ -14,6 +14,11 @@
>  #include "refs.h"
>  #include "connect.h"
>
> +#define OPT_QUIET (1 << 0)
> +
> +typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
> +                                 void *cb_data);

What is the reason for having the definition of 'each_submodule_fn' so
far removed textually from its first reference by
for_each_listed_submodule() below?

>  static char *get_default_remote(void)
>  {
>         char *dest = NULL, *ret;
> @@ -348,7 +353,23 @@ static int module_list(int argc, const char **argv, const char *prefix)
>         return 0;
>  }
>
> -static void init_submodule(const char *path, const char *prefix, int quiet)
> +static void for_each_listed_submodule(const struct module_list *list,
> +                                     each_submodule_fn fn, void *cb_data)
> +{
> +       int i;
> +       for (i = 0; i < list->nr; i++)
> +               fn(list->entries[i], cb_data);
> +}

I'm very curious about the justification for introducing a for-each
function for what amounts to the simplest sort of loop possible: a
canonical for-loop with a one-line body. I could easily understand the
desire for such a function if either the loop conditions or the body
of the loop, or both, were complex, but this does not seem to be the
case. Even the callers of this new function, in this patch and in 3/3,
are as simple as possible: one-liners (simple function calls).

Although this sort of for-each function can, at times, be helpful,
there are costs: extra boilerplate and increased complexity for
clients since it requires callback functions and (optionally) callback
data. The separation of logic into a callback function can make code
more difficult to reason about than when it is simply the body of a
for-loop.

So, unless the plan for the future is that this for-each function will
have considerable additional functionality baked into it, I'm having a
difficult time understanding why this change is desirable.

> +struct init_cb {
> +       const char *prefix;
> +       unsigned int flags;
> +};
> +
> +#define INIT_CB_INIT { NULL, 0 }

Why are these definitions so far removed from init_submodule_cb() below?

> +static void init_submodule(const char *path, const char *prefix,
> +                          unsigned int flags)
>  {
>         const struct submodule *sub;
>         struct strbuf sb = STRBUF_INIT;
> @@ -410,7 +431,7 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>                 if (git_config_set_gently(sb.buf, url))
>                         die(_("Failed to register url for submodule path '%s'"),
>                             displaypath);
> -               if (!quiet)
> +               if (!(flags & OPT_QUIET))

This change of having init_submodule() accept a 'flags' argument,
rather than a single boolean, increases reviewer burden, since the
reviewer is forced to puzzle out how this change relates to the stated
intention of the patch since it is not mentioned at all by the commit
message.

It's also conceptually unrelated to the introduction of a for-each
function, thus should be instead be done by a separate preparatory
patch.

>                         fprintf(stderr,
>                                 _("Submodule '%s' (%s) registered for path '%s'\n"),
>                                 sub->name, url, displaypath);
> @@ -437,12 +458,18 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>         free(upd);
>  }
>
> +static void init_submodule_cb(const struct cache_entry *list_item, void *cb_data)
> +{
> +       struct init_cb *info = cb_data;
> +       init_submodule(list_item->name, info->prefix, info->flags);
> +}
> +
>  static int module_init(int argc, const char **argv, const char *prefix)
>  {
> +       struct init_cb info = INIT_CB_INIT;
>         struct pathspec pathspec;
>         struct module_list list = MODULE_LIST_INIT;
>         int quiet = 0;
> -       int i;
>
>         struct option module_init_options[] = {
>                 OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
> @@ -467,8 +494,11 @@ static int module_init(int argc, const char **argv, const char *prefix)
>         if (!argc && git_config_get_value_multi("submodule.active"))
>                 module_list_active(&list);
>
> -       for (i = 0; i < list.nr; i++)
> -               init_submodule(list.entries[i]->name, prefix, quiet);
> +       info.prefix = prefix;
> +       if (quiet)
> +               info.flags |= OPT_QUIET;
> +
> +       for_each_listed_submodule(&list, init_submodule_cb, &info);
>
>         return 0;
>  }
> --
> 2.14.2

Re: [PATCH v7 0/3] Incremental rewrite of git-submodules

[Junio C Hamano]

Prathamesh Chavan <pc44800@gmail.com> writes:

> Changes in v7:

FWIW, the previous one is at

    https://public-inbox.org/git/20170929094453.4499-1-pc44800@gmail.com

Alternatively, the References link can be followed back from the
cover letter to go back to quite an early iteration of the series.

Hope that helps ;-)

Re: [PATCH v7 0/3] Incremental rewrite of git-submodules

[Eric Sunshine]

On Sat, Oct 7, 2017 at 4:51 AM, Junio C Hamano <gitster@pobox.com> wrote:
> FWIW, the previous one is at
>     https://public-inbox.org/git/20170929094453.4499-1-pc44800@gmail.com
> Hope that helps ;-)

Thanks, it does help.

Having scanned discussions of previous versions, I see that some of my
comments do indeed overlap (and sometimes are at odds) with comments
from other reviewers.