[GSOC Update] Week 7

[GSOC Update] Week 7

[Pranit Bauva]

================================= SUMMARY ==================================
My public git.git is available here[1]. I regularly keep pushing my work so
anyone interested can track me there. Feel free to participate in the
discussions going on PRs with my mentors. Your comments are valuable.


=============================== INTRODUCTION  ==============================
The purpose of this project is to convert the git-bisect utility which partly
exists in the form of shell scripts to C code so as to make it more portable.
I plan to do this by converting each function to C and then calling it from
git-bisect.sh so as to use the existing test suite to test the function which
is converted.

Mentors:
Christian Couder <chriscool@tuxfamily.org>
Lars Schneider <larsxschneider@gmail.com>


================================== Updates =================================
Things which were done in this week:

 * I have converted check_and_set_terms() and have also sent an RFC[2] to the
   mailing list for discussion which hasn't yet collected any comments. It is
   kind of important to discuss this as it uses a way to set the global
   variables in the script by writing it to a file and then reading it.

 * I have also converted bisect_next_check() but this has a bug which will
   soon be fixed. This is available here[3].

 * I have converted get_terms().

 * I am on my way to convert bisect_terms() which should probably finish by
   tomorrow.

 * I also send out a patch[4] which describes the return value of
   strbuf_read_file() and is queued on the pu branch.

================================= NEXT STEPS ================================
Things which would be done in the coming week:

 * Finish off bisect_terms().

 * bisect_run().

 * bisect_replay().

 * I have my mid term evaluations this week. Hope I clear it successfully.

[1]: https://github.com/pranitbauva1997/git
[2]: http://thread.gmane.org/gmane.comp.version-control.git/297520
[3]: https://github.com/pranitbauva1997/git/pull/17
[4]: http://thread.gmane.org/gmane.comp.version-control.git/297266

Regards,
Pranit Bauva

[GSoC] Update: Week 7

[Prathamesh Chavan]

SUMMARY OF MY PROJECT:

Git submodule subcommands are currently implemented by using shell script
'git-submodule.sh'. There are several reasons why we'll prefer not to
use the shell script. My project intends to convert the subcommands into
C code, thus making them builtins. This will increase Git's portability
and hence the efficiency of working with the git-submodule commands.
Link to the complete proposal: [1]

Mentors:
Stefan Beller <sbeller@google.com>
Christian Couder <christian.couder@gmail.com>

UPDATES:

Following are the updates about my ongoing project:

1. sync and status: The patches are updates after the last
   discussion, and will be posted with this update, along
   with the patches of the function get_submodule_displaypath()
   and for_each_submodule_list().

2. deinit: The patch was discussed in the last update, and
   I still have to make the required changes to this patch.

3. summary: I'm still working on debugging this patch as
   the are still some part where the patch isn't working as
   expected.

4. foreach: Most of the time was spent in reading the repo-object
   patch series. Also, currently I'm still confused about the
   approach I have to take for carrying this out.

PLAN FOR WEEK-8 (4 July 2017 to 10 July 2017):

The main focus for this week will be to get the reviewed code merged
by sending new version after their review. Hence, I've attached
the patches which were recently review, after adding the
suggested changes, with this update. Other than that, there is still
lots of work related to porting left as follows:

1. foreach: I'll try to come up with an approach for the present
   problem in the foreach patch, and get this discussed with
   mentors as well as with Brandon Williams so that I can
   get this subcommand ported.

2. summary: Currently, I'm still on debugging the patch. There are
   parts of the patch which aren't running as expected and hence
   it is taking more time to figure it out.

3. deinit: The patch was reviewed in the last update and I'm yet to
   work on the improving the patches as suggested.

Apart from this, there still lie two submodule subcommands: 'add' and
'update' unported.
I'll try to completed as much as work related to porting but will
also, focus on improving the code completed so that it becomes good
for merging.

[1]: https://docs.google.com/document/d/1krxVLooWl--75Pot3dazhfygR3wCUUWZWzTXtK1L-xU/

Thanks,
Prathamesh Chavan

[GSoC][PATCH 1/5 v4] 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>
---
This series of patches are build over the 'mater' branch.

Complete build report is available at:
https://travis-ci.org/pratham-pc/git/builds
Branch: setnamerev
Build #119

 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 8517032b3..1bfc91bca 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_sha1, 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_initialized(path)) {
-		strbuf_reset(&sb);
 		strbuf_addf(&sb, "submodule.%s.active", sub->name);
 		git_config_set_gently(sb.buf, "true");
 	}
-- 
2.13.0

[GSoC][PATCH 2/5 v4] 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 1bfc91bca..c4286aac5 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_sha1, path);
+	sub = submodule_from_path(null_sha1, 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_initialized(path)) {
+	if (!is_submodule_initialized(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 3/5 v4] 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>
---
As suggested the unnecessary enum present was removed.

 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 c4286aac5..5884a9725 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");
+
+	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 4/5 v4] 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>
---
A NEEDSWORK tag was added at the two places where optimization
for future.

 builtin/submodule--helper.c | 154 ++++++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh            |  49 +-------------
 2 files changed, 155 insertions(+), 48 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 5884a9725..d67a97062 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -560,6 +560,159 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+struct status_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+	unsigned int recursive: 1;
+	unsigned int cached: 1;
+};
+#define STATUS_CB_INIT { NULL, 0, 0, 0 }
+
+static void print_status(struct status_cb *info, char state, const char *path,
+			 char *sub_sha1, char *displaypath)
+{
+	if (info->quiet)
+		return;
+
+	printf("%c%s %s", state, sub_sha1, displaypath);
+
+	if (state == ' ' || state == '+') {
+		struct argv_array name_rev_args = ARGV_ARRAY_INIT;
+
+		argv_array_pushl(&name_rev_args, "print-name-rev",
+				 path, sub_sha1, NULL);
+		print_name_rev(name_rev_args.argc, name_rev_args.argv,
+			       info->prefix);
+	} else {
+		printf("\n");
+	}
+}
+
+static void status_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct status_cb *info = cb_data;
+	char *sub_sha1 = xstrdup(oid_to_hex(&list_item->oid));
+	char *displaypath;
+	struct argv_array diff_files_args = ARGV_ARRAY_INIT;
+
+	if (!submodule_from_path(null_sha1, list_item->name))
+		die(_("no submodule mapping found in .gitmodules for path '%s'"),
+		      list_item->name);
+
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
+
+	if (list_item->ce_flags) {
+		print_status(info, 'U', list_item->name,
+			     sha1_to_hex(null_sha1), displaypath);
+		goto cleanup;
+	}
+
+	if (!is_submodule_initialized(list_item->name)) {
+		print_status(info, '-', list_item->name, sub_sha1, displaypath);
+		goto cleanup;
+	}
+
+	argv_array_pushl(&diff_files_args, "diff-files",
+			 "--ignore-submodules=dirty", "--quiet", "--",
+			 list_item->name, NULL);
+
+	/* NEEDSWORK: future optimization possible */
+	if (!cmd_diff_files(diff_files_args.argc, diff_files_args.argv,
+			    info->prefix)) {
+		print_status(info, ' ', list_item->name, sub_sha1, displaypath);
+	} else {
+		if (!info->cached) {
+			struct child_process cp = CHILD_PROCESS_INIT;
+			struct strbuf sb = STRBUF_INIT;
+
+			prepare_submodule_repo_env(&cp.env_array);
+			cp.git_cmd = 1;
+			cp.dir = list_item->name;
+
+			argv_array_pushl(&cp.args, "rev-parse",
+					 "--verify", "HEAD", NULL);
+
+			/* NEEDSWORK: future optimization possible */
+			if (capture_command(&cp, &sb, 0))
+				die(_("could not run 'git rev-parse --verify"
+				      "HEAD' in submodule %s"),
+				      list_item->name);
+
+			strbuf_strip_suffix(&sb, "\n");
+			print_status(info, '+', list_item->name, sb.buf,
+				     displaypath);
+			strbuf_release(&sb);
+		} else {
+			print_status(info, '+', list_item->name, sub_sha1,
+				     displaypath);
+		}
+	}
+
+	if (info->recursive) {
+		struct child_process cpr = CHILD_PROCESS_INIT;
+
+		cpr.git_cmd = 1;
+		cpr.dir = list_item->name;
+		prepare_submodule_repo_env(&cpr.env_array);
+
+		argv_array_pushl(&cpr.args, "--super-prefix", displaypath,
+				 "submodule--helper", "status", "--recursive",
+				 NULL);
+
+		if (info->cached)
+			argv_array_push(&cpr.args, "--cached");
+
+		if (info->quiet)
+			argv_array_push(&cpr.args, "--quiet");
+
+		if (run_command(&cpr))
+			die(_("failed to recurse into submodule '%s'"),
+			      list_item->name);
+	}
+
+cleanup:
+	free(displaypath);
+	free(sub_sha1);
+}
+
+static int module_status(int argc, const char **argv, const char *prefix)
+{
+	struct status_cb info = STATUS_CB_INIT;
+	struct pathspec pathspec;
+	struct module_list list = MODULE_LIST_INIT;
+	int quiet = 0;
+	int cached = 0;
+	int recursive = 0;
+
+	struct option module_status_options[] = {
+		OPT__QUIET(&quiet, N_("Suppress submodule status output")),
+		OPT_BOOL(0, "cached", &cached, N_("Use commit stored in the index instead of the one stored in the submodule HEAD")),
+		OPT_BOOL(0, "recursive", &recursive, N_("Recurse into nested submodules")),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule status [--quiet] [--cached] [--recursive] [<path>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_status_options,
+			     git_submodule_helper_usage, 0);
+
+	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
+		return 1;
+
+	info.prefix = prefix;
+	info.quiet = !!quiet;
+	info.recursive = !!recursive;
+	info.cached = !!cached;
+
+	gitmodules_config();
+	for_each_submodule_list(list, status_submodule, &info);
+
+	return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
 	const struct submodule *sub;
@@ -1306,6 +1459,7 @@ static struct cmd_struct commands[] = {
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"print-name-rev", print_name_rev, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
+	{"status", module_status, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
 	{"push-check", push_check, 0},
 	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
diff --git a/git-submodule.sh b/git-submodule.sh
index e988167e0..51b057d82 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1005,54 +1005,7 @@ cmd_status()
 		shift
 	done
 
-	{
-		git submodule--helper list --prefix "$wt_prefix" "$@" ||
-		echo "#unmatched" $?
-	} |
-	while read -r mode sha1 stage sm_path
-	do
-		die_if_unmatched "$mode" "$sha1"
-		name=$(git submodule--helper name "$sm_path") || exit
-		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
-		if test "$stage" = U
-		then
-			say "U$sha1 $displaypath"
-			continue
-		fi
-		if ! git submodule--helper is-active "$sm_path" ||
-		{
-			! test -d "$sm_path"/.git &&
-			! test -f "$sm_path"/.git
-		}
-		then
-			say "-$sha1 $displaypath"
-			continue;
-		fi
-		if git diff-files --ignore-submodules=dirty --quiet -- "$sm_path"
-		then
-			revname=$(git submodule--helper print-name-rev "$sm_path" "$sha1")
-			say " $sha1 $displaypath$revname"
-		else
-			if test -z "$cached"
-			then
-				sha1=$(sanitize_submodule_env; cd "$sm_path" && git rev-parse --verify HEAD)
-			fi
-			revname=$(git submodule--helper print-name-rev "$sm_path" "$sha1")
-			say "+$sha1 $displaypath$revname"
-		fi
-
-		if test -n "$recursive"
-		then
-			(
-				prefix="$displaypath/"
-				sanitize_submodule_env
-				wt_prefix=
-				cd "$sm_path" &&
-				eval cmd_status
-			) ||
-			die "$(eval_gettext "Failed to recurse into submodule path '\$sm_path'")"
-		fi
-	done
+	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper status ${GIT_QUIET:+--quiet} ${cached:+--cached} ${recursive:+--recursive} "$@"
 }
 #
 # Sync remote urls for submodules
-- 
2.13.0

[GSoC][PATCH 5/5 v4] submodule: port submodule subcommand 'sync' from shell to C

[Prathamesh Chavan]

Port the submodule subcommand 'sync' from shell to C using the same
mechanism as that used for porting submodule subcommand 'status'.
Hence, here the function cmd_sync() is ported from shell to C.
This is done by introducing three functions: module_sync(),
sync_submodule() and print_default_remote().

The function print_default_remote() is introduced for getting
the default remote as stdout.

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 | 181 +++++++++++++++++++++++++++++++++++++++++++-
 git-submodule.sh            |  56 +-------------
 2 files changed, 181 insertions(+), 56 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index d67a97062..f28391634 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -44,6 +44,20 @@ static char *get_default_remote(void)
 	return ret;
 }
 
+static int print_default_remote(int argc, const char **argv, const char *prefix)
+{
+	const char *remote;
+
+	if (argc != 1)
+		die(_("submodule--helper print-default-remote takes no arguments"));
+
+	remote = get_default_remote();
+	if (remote)
+		puts(remote);
+
+	return 0;
+}
+
 static int starts_with_dot_slash(const char *str)
 {
 	return str[0] == '.' && is_dir_sep(str[1]);
@@ -379,6 +393,25 @@ static void module_list_active(struct module_list *list)
 	*list = active_modules;
 }
 
+static char *get_up_path(const char *path)
+{
+	int i;
+	struct strbuf sb = STRBUF_INIT;
+
+	for (i = count_slashes(path); i; i--)
+		strbuf_addstr(&sb, "../");
+
+	/*
+	 * Check if 'path' ends with slash or not
+	 * for having the same output for dir/sub_dir
+	 * and dir/sub_dir/
+	 */
+	if (!is_dir_sep(path[strlen(path) - 1]))
+		strbuf_addstr(&sb, "../");
+
+	return strbuf_detach(&sb, NULL);
+}
+
 static int module_list(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -478,16 +511,18 @@ static void init_submodule(const struct cache_entry *list_item, void *cb_data)
 			char *remote = get_default_remote();
 			struct strbuf remotesb = STRBUF_INIT;
 			strbuf_addf(&remotesb, "remote.%s.url", remote);
-			free(remote);
 
 			if (git_config_get_string(remotesb.buf, &remoteurl)) {
 				warning(_("could not lookup configuration '%s'. Assuming this repository is its own authoritative upstream."), remotesb.buf);
 				remoteurl = xgetcwd();
 			}
 			relurl = relative_url(remoteurl, url, NULL);
+
+			free(remote);
 			strbuf_release(&remotesb);
 			free(remoteurl);
 			free(url);
+
 			url = relurl;
 		}
 
@@ -732,6 +767,148 @@ static int module_name(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+struct sync_cb {
+	const char *prefix;
+	unsigned int quiet: 1;
+	unsigned int recursive: 1;
+};
+#define SYNC_CB_INIT { NULL, 0, 0 }
+
+static void sync_submodule(const struct cache_entry *list_item, void *cb_data)
+{
+	struct sync_cb *info = cb_data;
+	const struct submodule *sub;
+	char *sub_key, *remote_key;
+	char *sub_origin_url, *super_config_url, *displaypath;
+	struct strbuf sb = STRBUF_INIT;
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	if (!is_submodule_initialized(list_item->name))
+		return;
+
+	sub = submodule_from_path(null_sha1, list_item->name);
+
+	if (!sub || !sub->url)
+		die(_("no url found for submodule path '%s' in .gitmodules"),
+		      list_item->name);
+
+	if (starts_with_dot_dot_slash(sub->url) || starts_with_dot_slash(sub->url)) {
+		char *remote_url, *up_path;
+		char *remote = get_default_remote();
+		char *remote_key = xstrfmt("remote.%s.url", remote);
+		free(remote);
+
+		if (git_config_get_string(remote_key, &remote_url))
+			remote_url = xgetcwd();
+		up_path = get_up_path(list_item->name);
+		sub_origin_url = relative_url(remote_url, sub->url, up_path);
+		super_config_url = relative_url(remote_url, sub->url, NULL);
+		free(remote_key);
+		free(up_path);
+		free(remote_url);
+	} else {
+		sub_origin_url = xstrdup(sub->url);
+		super_config_url = xstrdup(sub->url);
+	}
+
+	displaypath = get_submodule_displaypath(list_item->name, info->prefix);
+
+	if (!info->quiet)
+		printf(_("Synchronizing submodule url for '%s'\n"),
+			 displaypath);
+
+	sub_key = xstrfmt("submodule.%s.url", sub->name);
+	if (git_config_set_gently(sub_key, super_config_url))
+		die(_("failed to register url for submodule path '%s'"),
+		      displaypath);
+
+	if (!is_submodule_populated_gently(list_item->name, NULL))
+		goto cleanup;
+
+	prepare_submodule_repo_env(&cp.env_array);
+	cp.git_cmd = 1;
+	cp.dir = list_item->name;
+	argv_array_pushl(&cp.args, "submodule--helper",
+			 "print-default-remote", NULL);
+	if (capture_command(&cp, &sb, 0))
+		die(_("failed to get the default remote for submodule '%s'"),
+		      list_item->name);
+
+	strbuf_strip_suffix(&sb, "\n");
+	remote_key = xstrfmt("remote.%s.url", sb.buf);
+	strbuf_release(&sb);
+
+	child_process_init(&cp);
+	prepare_submodule_repo_env(&cp.env_array);
+	cp.git_cmd = 1;
+	cp.dir = list_item->name;
+	argv_array_pushl(&cp.args, "config", remote_key, sub_origin_url, NULL);
+	if (run_command(&cp))
+		die(_("failed to update remote for submodule '%s'"),
+		      list_item->name);
+
+	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", "sync", "--recursive",
+				 NULL);
+
+		if (info->quiet)
+			argv_array_push(&cpr.args, "--quiet");
+
+		if (run_command(&cpr))
+			die(_("failed to recurse into submodule '%s'"),
+			      list_item->name);
+	}
+
+cleanup:
+	free(sub_key);
+	free(super_config_url);
+	free(displaypath);
+	free(sub_origin_url);
+}
+
+static int module_sync(int argc, const char **argv, const char *prefix)
+{
+	struct sync_cb info = SYNC_CB_INIT;
+	struct pathspec pathspec;
+	struct module_list list = MODULE_LIST_INIT;
+	int quiet = 0;
+	int recursive = 0;
+
+	struct option module_sync_options[] = {
+		OPT__QUIET(&quiet, N_("Suppress output of synchronizing submodule url")),
+		OPT_BOOL(0, "recursive", &recursive,
+			N_("Recurse into nested submodules")),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper sync [--quiet] [--recursive] [<path>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_sync_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;
+
+	gitmodules_config();
+	for_each_submodule_list(list, sync_submodule, &info);
+
+	return 0;
+}
+
 static int clone_submodule(const char *path, const char *gitdir, const char *url,
 			   const char *depth, struct string_list *reference,
 			   int quiet, int progress)
@@ -1460,6 +1637,8 @@ static struct cmd_struct commands[] = {
 	{"print-name-rev", print_name_rev, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"status", module_status, SUPPORT_SUPER_PREFIX},
+	{"print-default-remote", print_default_remote, 0},
+	{"sync", module_sync, 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 51b057d82..6bfc5e17d 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1037,63 +1037,9 @@ cmd_sync()
 			;;
 		esac
 	done
-	cd_to_toplevel
-	{
-		git submodule--helper list --prefix "$wt_prefix" "$@" ||
-		echo "#unmatched" $?
-	} |
-	while read -r mode sha1 stage sm_path
-	do
-		die_if_unmatched "$mode" "$sha1"
-
-		# skip inactive submodules
-		if ! git submodule--helper is-active "$sm_path"
-		then
-			continue
-		fi
-
-		name=$(git submodule--helper name "$sm_path")
-		url=$(git config -f .gitmodules --get submodule."$name".url)
-
-		# Possibly a url relative to parent
-		case "$url" in
-		./*|../*)
-			# rewrite foo/bar as ../.. to find path from
-			# submodule work tree to superproject work tree
-			up_path="$(printf '%s\n' "$sm_path" | sed "s/[^/][^/]*/../g")" &&
-			# guarantee a trailing /
-			up_path=${up_path%/}/ &&
-			# path from submodule work tree to submodule origin repo
-			sub_origin_url=$(git submodule--helper resolve-relative-url "$url" "$up_path") &&
-			# path from superproject work tree to submodule origin repo
-			super_config_url=$(git submodule--helper resolve-relative-url "$url") || exit
-			;;
-		*)
-			sub_origin_url="$url"
-			super_config_url="$url"
-			;;
-		esac
 
-		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
-		say "$(eval_gettext "Synchronizing submodule url for '\$displaypath'")"
-		git config submodule."$name".url "$super_config_url"
-
-		if test -e "$sm_path"/.git
-		then
-		(
-			sanitize_submodule_env
-			cd "$sm_path"
-			remote=$(get_default_remote)
-			git config remote."$remote".url "$sub_origin_url"
+	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper sync ${GIT_QUIET:+--quiet} ${recursive:+--recursive} "$@"
 
-			if test -n "$recursive"
-			then
-				prefix="$prefix$sm_path/"
-				eval cmd_sync
-			fi
-		)
-		fi
-	done
 }
 
 cmd_absorbgitdirs()
-- 
2.13.0