maintenance: add [un]register subcommands

In preparation for launching background maintenance from the 'git
maintenance' builtin, create register/unregister subcommands. These
commands update the new 'maintenance.repos' config option in the global
config so the background maintenance job knows which repositories to
maintain.

These commands allow users to add a repository to the background
maintenance list without disrupting the actual maintenance mechanism.

For example, a user can run 'git maintenance register' when no
background maintenance is running and it will not start the background
maintenance. A later update to start running background maintenance will
then pick up this repository automatically.

The opposite example is that a user can run 'git maintenance unregister'
to remove the current repository from background maintenance without
halting maintenance for other repositories.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 54 insertions, 1 deletions

diff --git a/builtin/gc.c b/builtin/gc.c
index 03b24ea0db..edf1d35ce5 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1407,7 +1407,56 @@ static int maintenance_run(int argc, const char **argv, const char *prefix)
 	return maintenance_run_tasks(&opts);
 }
 
-static const char builtin_maintenance_usage[] = N_("git maintenance run [<options>]");
+static int maintenance_register(void)
+{
+	struct child_process config_set = CHILD_PROCESS_INIT;
+	struct child_process config_get = CHILD_PROCESS_INIT;
+
+	/* There is no current repository, so skip registering it */
+	if (!the_repository || !the_repository->gitdir)
+		return 0;
+
+	config_get.git_cmd = 1;
+	strvec_pushl(&config_get.args, "config", "--global", "--get", "maintenance.repo",
+		     the_repository->worktree ? the_repository->worktree
+					      : the_repository->gitdir,
+			 NULL);
+	config_get.out = -1;
+
+	if (start_command(&config_get))
+		return error(_("failed to run 'git config'"));
+
+	/* We already have this value in our config! */
+	if (!finish_command(&config_get))
+		return 0;
+
+	config_set.git_cmd = 1;
+	strvec_pushl(&config_set.args, "config", "--add", "--global", "maintenance.repo",
+		     the_repository->worktree ? the_repository->worktree
+					      : the_repository->gitdir,
+		     NULL);
+
+	return run_command(&config_set);
+}
+
+static int maintenance_unregister(void)
+{
+	struct child_process config_unset = CHILD_PROCESS_INIT;
+
+	if (!the_repository || !the_repository->gitdir)
+		return error(_("no current repository to unregister"));
+
+	config_unset.git_cmd = 1;
+	strvec_pushl(&config_unset.args, "config", "--global", "--unset",
+		     "maintenance.repo",
+		     the_repository->worktree ? the_repository->worktree
+					      : the_repository->gitdir,
+		     NULL);
+
+	return run_command(&config_unset);
+}
+
+static const char builtin_maintenance_usage[] =	N_("git maintenance <subcommand> [<options>]");
 
 int cmd_maintenance(int argc, const char **argv, const char *prefix)
 {
@@ -1417,6 +1466,10 @@ int cmd_maintenance(int argc, const char **argv, const char *prefix)
 
 	if (!strcmp(argv[1], "run"))
 		return maintenance_run(argc - 1, argv + 1, prefix);
+	if (!strcmp(argv[1], "register"))
+		return maintenance_register();
+	if (!strcmp(argv[1], "unregister"))
+		return maintenance_unregister();
 
 	die(_("invalid subcommand: %s"), argv[1]);
 }