submodule: rewrite `module_clone` shell function in C

This reimplements the helper function `module_clone` in shell
in C as `clone`. This functionality is needed for converting
`git submodule update` later on, which we want to add threading
to.

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

1 files changed, 132 insertions, 0 deletions

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index bc79c41b58..f4c3eff179 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -8,6 +8,7 @@
 #include "submodule.h"
 #include "submodule-config.h"
 #include "string-list.h"
+#include "run-command.h"
 
 struct module_list {
 	const struct cache_entry **entries;
@@ -123,6 +124,136 @@ static int module_name(int argc, const char **argv, const char *prefix)
 
 	return 0;
 }
+static int clone_submodule(const char *path, const char *gitdir, const char *url,
+			   const char *depth, const char *reference, int quiet)
+{
+	struct child_process cp;
+	child_process_init(&cp);
+
+	argv_array_push(&cp.args, "clone");
+	argv_array_push(&cp.args, "--no-checkout");
+	if (quiet)
+		argv_array_push(&cp.args, "--quiet");
+	if (depth && *depth)
+		argv_array_pushl(&cp.args, "--depth", depth, NULL);
+	if (reference && *reference)
+		argv_array_pushl(&cp.args, "--reference", reference, NULL);
+	if (gitdir && *gitdir)
+		argv_array_pushl(&cp.args, "--separate-git-dir", gitdir, NULL);
+
+	argv_array_push(&cp.args, url);
+	argv_array_push(&cp.args, path);
+
+	cp.git_cmd = 1;
+	cp.env = local_repo_env;
+	cp.no_stdin = 1;
+
+	return run_command(&cp);
+}
+
+static int module_clone(int argc, const char **argv, const char *prefix)
+{
+	const char *path = NULL, *name = NULL, *url = NULL;
+	const char *reference = NULL, *depth = NULL;
+	int quiet = 0;
+	FILE *submodule_dot_git;
+	char *sm_gitdir, *cwd, *p;
+	struct strbuf rel_path = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
+
+	struct option module_clone_options[] = {
+		OPT_STRING(0, "prefix", &prefix,
+			   N_("path"),
+			   N_("alternative anchor for relative paths")),
+		OPT_STRING(0, "path", &path,
+			   N_("path"),
+			   N_("where the new submodule will be cloned to")),
+		OPT_STRING(0, "name", &name,
+			   N_("string"),
+			   N_("name of the new submodule")),
+		OPT_STRING(0, "url", &url,
+			   N_("string"),
+			   N_("url where to clone the submodule from")),
+		OPT_STRING(0, "reference", &reference,
+			   N_("string"),
+			   N_("reference repository")),
+		OPT_STRING(0, "depth", &depth,
+			   N_("string"),
+			   N_("depth for shallow clones")),
+		OPT__QUIET(&quiet, "Suppress output for cloning a submodule"),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper clone [--prefix=<path>] [--quiet] "
+		   "[--reference <repository>] [--name <name>] [--url <url>]"
+		   "[--depth <depth>] [--] [<path>...]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_clone_options,
+			     git_submodule_helper_usage, 0);
+
+	strbuf_addf(&sb, "%s/modules/%s", get_git_dir(), name);
+	sm_gitdir = strbuf_detach(&sb, NULL);
+
+	if (!file_exists(sm_gitdir)) {
+		if (safe_create_leading_directories_const(sm_gitdir) < 0)
+			die(_("could not create directory '%s'"), sm_gitdir);
+		if (clone_submodule(path, sm_gitdir, url, depth, reference, quiet))
+			die(_("clone of '%s' into submodule path '%s' failed"),
+			    url, path);
+	} else {
+		if (safe_create_leading_directories_const(path) < 0)
+			die(_("could not create directory '%s'"), path);
+		strbuf_addf(&sb, "%s/index", sm_gitdir);
+		unlink_or_warn(sb.buf);
+		strbuf_reset(&sb);
+	}
+
+	/* Write a .git file in the submodule to redirect to the superproject. */
+	if (safe_create_leading_directories_const(path) < 0)
+		die(_("could not create directory '%s'"), path);
+
+	if (path && *path)
+		strbuf_addf(&sb, "%s/.git", path);
+	else
+		strbuf_addstr(&sb, ".git");
+
+	if (safe_create_leading_directories_const(sb.buf) < 0)
+		die(_("could not create leading directories of '%s'"), sb.buf);
+	submodule_dot_git = fopen(sb.buf, "w");
+	if (!submodule_dot_git)
+		die_errno(_("cannot open file '%s'"), sb.buf);
+
+	fprintf(submodule_dot_git, "gitdir: %s\n",
+		relative_path(sm_gitdir, path, &rel_path));
+	if (fclose(submodule_dot_git))
+		die(_("could not close file %s"), sb.buf);
+	strbuf_reset(&sb);
+	strbuf_reset(&rel_path);
+
+	cwd = xgetcwd();
+	/* Redirect the worktree of the submodule in the superproject's config */
+	if (!is_absolute_path(sm_gitdir)) {
+		strbuf_addf(&sb, "%s/%s", cwd, sm_gitdir);
+		free(sm_gitdir);
+		sm_gitdir = strbuf_detach(&sb, NULL);
+	}
+
+	strbuf_addf(&sb, "%s/%s", cwd, path);
+	p = git_pathdup_submodule(path, "config");
+	if (!p)
+		die(_("could not get submodule directory for '%s'"), path);
+	git_config_set_in_file(p, "core.worktree",
+			       relative_path(sb.buf, sm_gitdir, &rel_path));
+	strbuf_release(&sb);
+	strbuf_release(&rel_path);
+	free(sm_gitdir);
+	free(cwd);
+	free(p);
+	return 0;
+}
 
 struct cmd_struct {
 	const char *cmd;
@@ -132,6 +263,7 @@ struct cmd_struct {
 static struct cmd_struct commands[] = {
 	{"list", module_list},
 	{"name", module_name},
+	{"clone", module_clone},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)