receive-pack: convert receive hooks to hook API

This converts the last remaining hooks to the new hook API, for
the same benefits as the previous conversions (no need to toggle
signals, manage custom struct child_process, call find_hook(),
prepares for specifying hooks via configs, etc.).

See the previous three commits for a more in-depth explanation of
how this all works.

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

Author: nasamuffin

builtin/receive-pack.c

@@ -791,7 +791,7 @@ static int check_cert_push_options(const struct string_list *push_options)
 	return retval;
 }
 
-static void prepare_push_cert_sha1(struct child_process *proc)
+static void prepare_push_cert_sha1(struct run_hooks_opt *opt)
 {
 	static int already_done;
 
@@ -817,23 +817,23 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 		nonce_status = check_nonce(sigcheck.payload);
 	}
 	if (!is_null_oid(&push_cert_oid)) {
-		strvec_pushf(&proc->env, "GIT_PUSH_CERT=%s",
+		strvec_pushf(&opt->env, "GIT_PUSH_CERT=%s",
 			     oid_to_hex(&push_cert_oid));
-		strvec_pushf(&proc->env, "GIT_PUSH_CERT_SIGNER=%s",
+		strvec_pushf(&opt->env, "GIT_PUSH_CERT_SIGNER=%s",
 			     sigcheck.signer ? sigcheck.signer : "");
-		strvec_pushf(&proc->env, "GIT_PUSH_CERT_KEY=%s",
+		strvec_pushf(&opt->env, "GIT_PUSH_CERT_KEY=%s",
 			     sigcheck.key ? sigcheck.key : "");
-		strvec_pushf(&proc->env, "GIT_PUSH_CERT_STATUS=%c",
+		strvec_pushf(&opt->env, "GIT_PUSH_CERT_STATUS=%c",
 			     sigcheck.result);
 		if (push_cert_nonce) {
-			strvec_pushf(&proc->env,
+			strvec_pushf(&opt->env,
 				     "GIT_PUSH_CERT_NONCE=%s",
 				     push_cert_nonce);
-			strvec_pushf(&proc->env,
+			strvec_pushf(&opt->env,
 				     "GIT_PUSH_CERT_NONCE_STATUS=%s",
 				     nonce_status);
 			if (nonce_status == NONCE_SLOP)
-				strvec_pushf(&proc->env,
+				strvec_pushf(&opt->env,
 					     "GIT_PUSH_CERT_NONCE_SLOP=%ld",
 					     nonce_stamp_slop);
 		}
@@ -845,94 +845,25 @@ struct receive_hook_feed_state {
 	struct ref_push_report *report;
 	int skip_broken;
 	struct strbuf buf;
-	const struct string_list *push_options;
 };
 
-typedef int (*feed_fn)(void *, const char **, size_t *);
-static int run_and_feed_hook(const char *hook_name, feed_fn feed,
-			     struct receive_hook_feed_state *feed_state)
+static int feed_receive_hook_cb(int hook_stdin_fd, void *pp_cb UNUSED, void *pp_task_cb)
 {
-	struct child_process proc = CHILD_PROCESS_INIT;
-	struct async muxer;
-	int code;
-	const char *hook_path = find_hook(the_repository, hook_name);
-
-	if (!hook_path)
-		return 0;
-
-	strvec_push(&proc.args, hook_path);
-	proc.in = -1;
-	proc.stdout_to_stderr = 1;
-	proc.trace2_hook_name = hook_name;
-
-	if (feed_state->push_options) {
-		size_t i;
-		for (i = 0; i < feed_state->push_options->nr; i++)
-			strvec_pushf(&proc.env,
-				     "GIT_PUSH_OPTION_%"PRIuMAX"=%s",
-				     (uintmax_t)i,
-				     feed_state->push_options->items[i].string);
-		strvec_pushf(&proc.env, "GIT_PUSH_OPTION_COUNT=%"PRIuMAX"",
-			     (uintmax_t)feed_state->push_options->nr);
-	} else
-		strvec_pushf(&proc.env, "GIT_PUSH_OPTION_COUNT");
-
-	if (tmp_objdir)
-		strvec_pushv(&proc.env, tmp_objdir_env(tmp_objdir));
-
-	if (use_sideband) {
-		memset(&muxer, 0, sizeof(muxer));
-		muxer.proc = copy_to_sideband;
-		muxer.in = -1;
-		code = start_async(&muxer);
-		if (code)
-			return code;
-		proc.err = muxer.in;
-	}
-
-	prepare_push_cert_sha1(&proc);
-
-	code = start_command(&proc);
-	if (code) {
-		if (use_sideband)
-			finish_async(&muxer);
-		return code;
-	}
-
-	sigchain_push(SIGPIPE, SIG_IGN);
-
-	while (1) {
-		const char *buf;
-		size_t n;
-		if (feed(feed_state, &buf, &n))
-			break;
-		if (write_in_full(proc.in, buf, n) < 0)
-			break;
-	}
-	close(proc.in);
-	if (use_sideband)
-		finish_async(&muxer);
-
-	sigchain_pop(SIGPIPE);
-
-	return finish_command(&proc);
-}
-
-static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
-{
-	struct receive_hook_feed_state *state = state_;
+	struct receive_hook_feed_state *state = pp_task_cb;
 	struct command *cmd = state->cmd;
 
+	strbuf_reset(&state->buf);
+
 	while (cmd &&
 	       state->skip_broken && (cmd->error_string || cmd->did_not_exist))
 		cmd = cmd->next;
+
 	if (!cmd)
-		return -1; /* EOF */
-	if (!bufp)
-		return 0; /* OK, can feed something. */
-	strbuf_reset(&state->buf);
+		return 1;  /* no more commands left */
+
 	if (!state->report)
 		state->report = cmd->report;
+
 	if (state->report) {
 		struct object_id *old_oid;
 		struct object_id *new_oid;
@@ -941,44 +872,85 @@ static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
 		old_oid = state->report->old_oid ? state->report->old_oid : &cmd->old_oid;
 		new_oid = state->report->new_oid ? state->report->new_oid : &cmd->new_oid;
 		ref_name = state->report->ref_name ? state->report->ref_name : cmd->ref_name;
+
 		strbuf_addf(&state->buf, "%s %s %s\n",
 			    oid_to_hex(old_oid), oid_to_hex(new_oid),
 			    ref_name);
+
 		state->report = state->report->next;
 		if (!state->report)
-			state->cmd = cmd->next;
+			cmd = cmd->next;
 	} else {
 		strbuf_addf(&state->buf, "%s %s %s\n",
 			    oid_to_hex(&cmd->old_oid), oid_to_hex(&cmd->new_oid),
 			    cmd->ref_name);
-		state->cmd = cmd->next;
+		cmd = cmd->next;
 	}
-	if (bufp) {
-		*bufp = state->buf.buf;
-		*sizep = state->buf.len;
+
+	state->cmd = cmd;
+
+	if (state->buf.len > 0) {
+		int ret = write_in_full(hook_stdin_fd, state->buf.buf, state->buf.len);
+		if (ret < 0) {
+			if (errno == EPIPE)
+				return 1; /* child closed pipe */
+			return ret;
+		}
 	}
-	return 0;
+
+	return state->cmd ? 0 : 1;  /* 0 = more to come, 1 = EOF */
 }
 
 static int run_receive_hook(struct command *commands,
 			    const char *hook_name,
 			    int skip_broken,
 			    const struct string_list *push_options)
 {
-	struct receive_hook_feed_state state;
-	int status;
+	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
+	struct command *iter = commands;
+	struct receive_hook_feed_state feed_state;
+	struct async sideband_async;
+	int sideband_async_started = 0;
+	int saved_stderr = -1;
+	int ret;
 
-	strbuf_init(&state.buf, 0);
-	state.cmd = commands;
-	state.skip_broken = skip_broken;
-	state.report = NULL;
-	if (feed_receive_hook(&state, NULL, NULL))
+	/* if there are no valid commands, don't invoke the hook at all. */
+	while (iter && skip_broken && (iter->error_string || iter->did_not_exist))
+		iter = iter->next;
+	if (!iter)
 		return 0;
-	state.cmd = commands;
-	state.push_options = push_options;
-	status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
-	strbuf_release(&state.buf);
-	return status;
+
+	if (push_options) {
+		for (int i = 0; i < push_options->nr; i++)
+			strvec_pushf(&opt.env, "GIT_PUSH_OPTION_%d=%s", i,
+				     push_options->items[i].string);
+		strvec_pushf(&opt.env, "GIT_PUSH_OPTION_COUNT=%"PRIuMAX"",
+					     (uintmax_t)push_options->nr);
+	} else {
+		strvec_push(&opt.env, "GIT_PUSH_OPTION_COUNT");
+	}
+
+	if (tmp_objdir)
+		strvec_pushv(&opt.env, tmp_objdir_env(tmp_objdir));
+
+	prepare_push_cert_sha1(&opt);
+
+	prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started);
+
+	/* set up stdin callback */
+	feed_state.cmd = commands;
+	feed_state.skip_broken = skip_broken;
+	feed_state.report = NULL;
+	strbuf_init(&feed_state.buf, 0);
+	opt.feed_pipe_cb_data = &feed_state;
+	opt.feed_pipe = feed_receive_hook_cb;
+
+	ret = run_hooks_opt(the_repository, hook_name, &opt);
+
+	strbuf_release(&feed_state.buf);
+	finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started);
+
+	return ret;
 }
 
 static int run_update_hook(struct command *cmd)