transport: convert pre-push to hook API

Move the pre-push hook from custom run-command invocations to
the new hook API which doesn't require a custom child_process
structure and signal toggling.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: nasamuffin

transport.c

@@ -1316,65 +1316,72 @@ static void die_with_unpushed_submodules(struct string_list *needs_pushing)
 	die(_("Aborting."));
 }
 
-static int run_pre_push_hook(struct transport *transport,
-			     struct ref *remote_refs)
-{
-	int ret = 0, x;
-	struct ref *r;
-	struct child_process proc = CHILD_PROCESS_INIT;
+struct feed_pre_push_hook_data {
 	struct strbuf buf;
-	const char *hook_path = find_hook(the_repository, "pre-push");
+	const struct ref *refs;
+};
 
-	if (!hook_path)
-		return 0;
+static int pre_push_hook_feed_stdin(int hook_stdin_fd, void *pp_cb UNUSED, void *pp_task_cb)
+{
+	struct feed_pre_push_hook_data *data = pp_task_cb;
+	const struct ref *r = data->refs;
+	int ret = 0;
 
-	strvec_push(&proc.args, hook_path);
-	strvec_push(&proc.args, transport->remote->name);
-	strvec_push(&proc.args, transport->url);
+	if (!r)
+		return 1; /* no more refs */
 
-	proc.in = -1;
-	proc.trace2_hook_name = "pre-push";
+	data->refs = r->next;
 
-	if (start_command(&proc)) {
-		finish_command(&proc);
-		return -1;
+	switch (r->status) {
+	case REF_STATUS_REJECT_NONFASTFORWARD:
+	case REF_STATUS_REJECT_REMOTE_UPDATED:
+	case REF_STATUS_REJECT_STALE:
+	case REF_STATUS_UPTODATE:
+		return 0; /* skip refs which won't be pushed */
+	default:
+		break;
 	}
 
-	sigchain_push(SIGPIPE, SIG_IGN);
+	if (!r->peer_ref)
+		return 0;
 
-	strbuf_init(&buf, 256);
+	strbuf_reset(&data->buf);
+	strbuf_addf(&data->buf, "%s %s %s %s\n",
+		    r->peer_ref->name, oid_to_hex(&r->new_oid),
+		    r->name, oid_to_hex(&r->old_oid));
 
-	for (r = remote_refs; r; r = r->next) {
-		if (!r->peer_ref) continue;
-		if (r->status == REF_STATUS_REJECT_NONFASTFORWARD) continue;
-		if (r->status == REF_STATUS_REJECT_STALE) continue;
-		if (r->status == REF_STATUS_REJECT_REMOTE_UPDATED) continue;
-		if (r->status == REF_STATUS_UPTODATE) continue;
+	ret = write_in_full(hook_stdin_fd, data->buf.buf, data->buf.len);
+	if (ret < 0 && errno != EPIPE)
+		return ret; /* We do not mind if a hook does not read all refs. */
 
-		strbuf_reset(&buf);
-		strbuf_addf( &buf, "%s %s %s %s\n",
-			 r->peer_ref->name, oid_to_hex(&r->new_oid),
-			 r->name, oid_to_hex(&r->old_oid));
+	return 0;
+}
 
-		if (write_in_full(proc.in, buf.buf, buf.len) < 0) {
-			/* We do not mind if a hook does not read all refs. */
-			if (errno != EPIPE)
-				ret = -1;
-			break;
-		}
-	}
+static int run_pre_push_hook(struct transport *transport,
+			     struct ref *remote_refs)
+{
+	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
+	struct feed_pre_push_hook_data data;
+	int ret = 0;
+
+	strvec_push(&opt.args, transport->remote->name);
+	strvec_push(&opt.args, transport->url);
 
-	strbuf_release(&buf);
+	strbuf_init(&data.buf, 0);
+	data.refs = remote_refs;
 
-	x = close(proc.in);
-	if (!ret)
-		ret = x;
+	opt.feed_pipe = pre_push_hook_feed_stdin;
+	opt.feed_pipe_cb_data = &data;
+
+	/*
+	 * pre-push hooks expect stdout & stderr to be separate, so don't merge
+	 * them to keep backwards compatibility with existing hooks.
+	 */
+	opt.stdout_to_stderr = 0;
 
-	sigchain_pop(SIGPIPE);
+	ret = run_hooks_opt(the_repository, "pre-push", &opt);
 
-	x = finish_command(&proc);
-	if (!ret)
-		ret = x;
+	strbuf_release(&data.buf);
 
 	return ret;
 }