check_connected: add progress flag

Connectivity checks have to traverse the entire object graph
in the worst case (e.g., a full clone or a full push). For
large repositories like linux.git, this can take 30-60
seconds, during which time git may produce little or no
output.

Let's add the option of showing progress, which is taken
care of by rev-list.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

connected.c

@@ -58,6 +58,9 @@ int check_connected(sha1_iterate_fn fn, void *cb_data,
 	argv_array_push(&rev_list.args, "--not");
 	argv_array_push(&rev_list.args, "--all");
 	argv_array_push(&rev_list.args, "--quiet");
+	if (opt->progress)
+		argv_array_pushf(&rev_list.args, "--progress=%s",
+				 _("Checking connectivity"));
 
 	rev_list.git_cmd = 1;
 	rev_list.in = -1;

connected.h

@@ -30,6 +30,9 @@ struct check_connected_options {
 	 * returns.
 	 */
 	int err_fd;
+
+	/* If non-zero, show progress as we traverse the objects. */
+	int progress;
 };
 
 #define CHECK_CONNECTED_INIT { 0 }