[PATCH/RFC 0/6] fetch with refspec

@@ -1010,7 +1010,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (transport->smart_options && !option_depth)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
-	refs = transport_get_remote_refs(transport);
+	refs = transport_get_remote_refs(transport, NULL, 0);
 
 	if (refs) {
 		mapped_refs = wanted_peer_refs(refs, refspec);

@@ -221,7 +221,8 @@ static void find_non_local_tags(struct transport *transport,
 	struct string_list_item *item = NULL;
 
 	for_each_ref(add_existing, &existing_refs);
-	for (ref = transport_get_remote_refs(transport); ref; ref = ref->next) {
+	for (ref = transport_get_remote_refs(transport, NULL, 0);
+	     ref; ref = ref->next) {
 		if (!starts_with(ref->name, "refs/tags/"))
 			continue;
 

@@ -301,8 +302,9 @@ static struct ref *get_ref_map(struct transport *transport,
 
 	/* opportunistically-updated references: */
 	struct ref *orefs = NULL, **oref_tail = &orefs;
+	const struct ref *remote_refs;
 
-	const struct ref *remote_refs = transport_get_remote_refs(transport);
+	remote_refs = transport_get_remote_refs(transport, NULL, 0);
 
 	if (refspec_count) {
 		struct refspec *fetch_refspec;

@@ -94,7 +94,7 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 	if (uploadpack != NULL)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK, uploadpack);
 
-	ref = transport_get_remote_refs(transport);
+	ref = transport_get_remote_refs(transport, NULL, 0);
 	if (transport_disconnect(transport))
 		return 1;
 

@@ -862,7 +862,7 @@ static int get_remote_ref_states(const char *name,
 	if (query) {
 		transport = transport_get(states->remote, states->remote->url_nr > 0 ?
 			states->remote->url[0] : NULL);
-		remote_refs = transport_get_remote_refs(transport);
+		remote_refs = transport_get_remote_refs(transport, NULL, 0);
 		transport_disconnect(transport);
 
 		states->queried = 1;

@@ -99,7 +99,7 @@ static void do_take_over(struct transport *transport)
 
 static void standard_options(struct transport *t);
 
-static struct child_process *get_helper(struct transport *transport)
+static struct child_process *get_helper(struct transport *transport, const struct refspec *req_refspecs, int req_refspec_nr)
 {
 	struct helper_data *data = transport->data;
 	struct strbuf buf = STRBUF_INIT;

@@ -267,7 +267,7 @@ static int set_helper_option(struct transport *transport,
 	struct strbuf buf = STRBUF_INIT;
 	int i, ret, is_bool = 0;
 
-	get_helper(transport);
+	get_helper(transport, NULL, 0);
 
 	if (!data->option)
 		return 1;

@@ -395,7 +395,7 @@ static int fetch_with_fetch(struct transport *transport,
 
 static int get_importer(struct transport *transport, struct child_process *fastimport)
 {
-	struct child_process *helper = get_helper(transport);
+	struct child_process *helper = get_helper(transport, NULL, 0);
 	struct helper_data *data = transport->data;
 	int cat_blob_fd, code;
 	child_process_init(fastimport);

@@ -418,7 +418,7 @@ static int get_exporter(struct transport *transport,
 			struct string_list *revlist_args)
 {
 	struct helper_data *data = transport->data;
-	struct child_process *helper = get_helper(transport);
+	struct child_process *helper = get_helper(transport, NULL, 0);
 	int i;
 
 	child_process_init(fastexport);

@@ -451,7 +451,7 @@ static int fetch_with_import(struct transport *transport,
 	struct ref *posn;
 	struct strbuf buf = STRBUF_INIT;
 
-	get_helper(transport);
+	get_helper(transport, NULL, 0);
 
 	if (get_importer(transport, &fastimport))
 		die("Couldn't run fast-import");

@@ -523,7 +523,7 @@ static int process_connect_service(struct transport *transport,
 	int r, duped, ret = 0;
 	FILE *input;
 
-	helper = get_helper(transport);
+	helper = get_helper(transport, NULL, 0);
 
 	/*
 	 * Yes, dup the pipe another time, as we need unbuffered version

@@ -599,7 +599,7 @@ static int connect_helper(struct transport *transport, const char *name,
 	struct helper_data *data = transport->data;
 
 	/* Get_helper so connect is inited. */
-	get_helper(transport);
+	get_helper(transport, NULL, 0);
 	if (!data->connect)
 		die("Operation not supported by protocol.");
 

@@ -805,7 +805,7 @@ static int push_refs_with_push(struct transport *transport,
 	struct string_list cas_options = STRING_LIST_INIT_DUP;
 	struct string_list_item *cas_option;
 
-	get_helper(transport);
+	get_helper(transport, NULL, 0);
 	if (!data->push)
 		return 1;
 

@@ -888,7 +888,7 @@ static int push_refs_with_export(struct transport *transport,
 			warning("helper %s does not support 'force'", data->name);
 	}
 
-	helper = get_helper(transport);
+	helper = get_helper(transport, NULL, 0);
 
 	write_constant(helper->in, "export\n");
 

@@ -992,7 +992,7 @@ static int has_attribute(const char *attrs, const char *attr) {
 	}
 }
 
-static struct ref *get_refs_list(struct transport *transport, int for_push)
+static struct ref *get_refs_list(struct transport *transport, const struct refspec *refspecs, int refspec_count, int for_push)
 {
 	struct helper_data *data = transport->data;
 	struct child_process *helper;

@@ -1001,11 +1001,11 @@ static struct ref *get_refs_list(struct transport *transport, int for_push)
 	struct ref *posn;
 	struct strbuf buf = STRBUF_INIT;
 
-	helper = get_helper(transport);
+	helper = get_helper(transport, refspecs, refspec_count);
 
 	if (process_connect(transport, for_push)) {
 		do_take_over(transport);
-		return transport->get_refs_list(transport, for_push);
+		return transport->get_refs_list(transport, refspecs, refspec_count, for_push);
 	}
 
 	if (data->push && for_push)

@@ -70,7 +70,9 @@ struct bundle_transport_data {
 	struct bundle_header header;
 };
 
-static struct ref *get_refs_from_bundle(struct transport *transport, int for_push)
+static struct ref *get_refs_from_bundle(struct transport *transport,
+					const struct refspec *refspecs,
+					int refspec_count, int for_push)
 {
 	struct bundle_transport_data *data = transport->data;
 	struct ref *result = NULL;

@@ -177,7 +179,7 @@ static int connect_setup(struct transport *transport, int for_push)
 	return 0;
 }
 
-static struct ref *get_refs_via_connect(struct transport *transport, int for_push)
+static struct ref *get_refs_via_connect(struct transport *transport, const struct refspec *refspecs, int refspec_count, int for_push)
 {
 	struct git_transport_data *data = transport->data;
 	struct ref *refs;

@@ -870,7 +872,7 @@ int transport_push(struct transport *transport,
 		if (check_push_refs(local_refs, refspec_nr, refspec) < 0)
 			return -1;
 
-		remote_refs = transport->get_refs_list(transport, 1);
+		remote_refs = transport->get_refs_list(transport, NULL, 0, 1);
 
 		if (flags & TRANSPORT_PUSH_ALL)
 			match_flags |= MATCH_REFS_ALL;

@@ -949,10 +951,10 @@ int transport_push(struct transport *transport,
 	return 1;
 }
 
-const struct ref *transport_get_remote_refs(struct transport *transport)
+const struct ref *transport_get_remote_refs(struct transport *transport, const struct refspec *refspecs, int refspec_count)
 {
 	if (!transport->got_remote_refs) {
-		transport->remote_refs = transport->get_refs_list(transport, 0);
+		transport->remote_refs = transport->get_refs_list(transport, refspecs, refspec_count, 0);
 		transport->got_remote_refs = 1;
 	}
 

@@ -1099,7 +1101,7 @@ static int refs_from_alternate_cb(struct alternate_object_database *e,
 	other[len - 8] = '\0';
 	remote = remote_get(other);
 	transport = transport_get(remote, other);
-	for (extra = transport_get_remote_refs(transport);
+	for (extra = transport_get_remote_refs(transport, NULL, 0);
 	     extra;
 	     extra = extra->next)
 		cb->fn(extra, cb->data);

@@ -65,7 +65,7 @@ struct transport {
 	 * the ref without a huge amount of effort, it should store it
 	 * in the ref's old_sha1 field; otherwise it should be all 0.
 	 **/
-	struct ref *(*get_refs_list)(struct transport *transport, int for_push);
+	struct ref *(*get_refs_list)(struct transport *transport, const struct refspec *refspecs, int refspec_count, int for_push);
 
 	/**
 	 * Fetch the objects for the given refs. Note that this gets

@@ -207,7 +207,7 @@ int transport_push(struct transport *connection,
 		   int refspec_nr, const char **refspec, int flags,
 		   unsigned int * reject_reasons);
 
-const struct ref *transport_get_remote_refs(struct transport *transport);
+const struct ref *transport_get_remote_refs(struct transport *transport, const struct refspec *refspecs, int refspec_count);
 
 int transport_fetch_refs(struct transport *transport, struct ref *refs);
 void transport_unlock_pack(struct transport *transport);

@@ -275,3 +275,26 @@ to accept a signed push certificate, and asks the <nonce> to be
 included in the push certificate.  A send-pack client MUST NOT
 send a push-cert packet unless the receive-pack server advertises
 this capability.
+
+interesting-refs
+----------------
+
+For HTTP(S) servers only:
+
+Whether or not the upload-pack server advertises this capability,
+fetch-pack may send a "refspec" parameter in the query string of a
+fetch request.  This capability indicates that such a parameter will
+be respected, in case the client cares.
+
+Whenever the receive-pack server gets that parameter, it will not
+advertise all refs and will instead only advertise refs that match
+those listed in the header. The parameter is a space-separated list of
+refs.  A ref may optionally contain up to one wildcard.
+Advertisements will still respect hideRefs.
+
+The presence or absence of the "refspec" parameter does not affect
+what refs a client is permitted to fetch; this is still controlled in
+the normal fashion.
+
+This saves time in the presence of a large number of refs, because the
+client need not wait for the server to send the complete list of refs.

@@ -302,9 +302,27 @@ static struct ref *get_ref_map(struct transport *transport,
 
 	/* opportunistically-updated references: */
 	struct ref *orefs = NULL, **oref_tail = &orefs;
+	struct refspec *qualified_refspecs;
 	const struct ref *remote_refs;
 
-	remote_refs = transport_get_remote_refs(transport, NULL, 0);
+	qualified_refspecs = xcalloc(refspec_count, sizeof(*qualified_refspecs));
+	for (i = 0; i < refspec_count; i++) {
+		if (starts_with(refspecs[i].src, "refs/")) {
+			qualified_refspecs[i].src = xstrdup(refspecs[i].src);
+		} else {
+			struct strbuf buf = STRBUF_INIT;
+			strbuf_addf(&buf, "refs/heads/%s", refspecs[i].src);
+			qualified_refspecs[i].src = strbuf_detach(&buf, NULL);
+		}
+	}
+
+	remote_refs = transport_get_remote_refs(transport, qualified_refspecs,
+						refspec_count);
+
+	for (i = 0; i < refspec_count; i++) {
+		free(qualified_refspecs[i].src);
+	}
+	free(qualified_refspecs);
 
 	if (refspec_count) {
 		struct refspec *fetch_refspec;

@@ -20,6 +20,7 @@ static struct strbuf url = STRBUF_INIT;
 struct options {
 	int verbosity;
 	unsigned long depth;
+	char *refspec;
 	unsigned progress : 1,
 		check_self_contained_and_connected : 1,
 		cloning : 1,

@@ -43,6 +44,10 @@ static int set_option(const char *name, const char *value)
 		options.verbosity = v;
 		return 0;
 	}
+	else if (!strcmp(name, "refspec")) {
+		options.refspec = xstrdup(value);
+		return 0;
+	}
 	else if (!strcmp(name, "progress")) {
 		if (!strcmp(value, "true"))
 			options.progress = 1;

@@ -269,6 +274,8 @@ static struct discovery *discover_refs(const char *service, int for_push)
 		else
 			strbuf_addch(&refs_url, '&');
 		strbuf_addf(&refs_url, "service=%s", service);
+		if (options.refspec)
+			strbuf_addf(&refs_url, "&refspec=%s", options.refspec);
 	}
 
 	memset(&get_options, 0, sizeof(get_options));

@@ -0,0 +1,42 @@
+#!/bin/sh
+
+test_description='fetch just one branch'
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'setup repo' '
+	git init "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
+	(
+		cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
+		test_commit 1
+	)
+'
+
+test_expect_success 'clone http repository' '
+	git clone $HTTPD_URL/smart/repo.git clone
+'
+
+test_expect_success 'make some more commits' '
+	(
+		cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
+		test_commit 2 &&
+		git checkout -b another_branch &&
+		test_commit 3
+		git checkout -b a_third_branch &&
+		test_commit 4
+	)
+'
+
+test_expect_success 'fetch with refspec only fetches requested branch' '
+	test_when_finished "rm trace" &&
+	(
+		cd clone &&
+		GIT_TRACE_PACKET="$TRASH_DIRECTORY/trace" git fetch origin another_branch &&
+		! grep "refs/heads/master" ../trace
+	)
+'
+
+stop_httpd
+test_done

@@ -40,6 +40,9 @@ struct helper_data {
 	struct git_transport_options transport_options;
 };
 
+static int set_helper_option(struct transport *transport,
+			     const char *name, const char *value);
+
 static void sendline(struct helper_data *helper, struct strbuf *buffer)
 {
 	if (debug)

@@ -109,6 +112,7 @@ static struct child_process *get_helper(struct transport *transport, const struc
 	int refspec_alloc = 0;
 	int duped;
 	int code;
+	int i;
 
 	if (data->helper)
 		return data->helper;

@@ -202,7 +206,6 @@ static struct child_process *get_helper(struct transport *transport, const struc
 		}
 	}
 	if (refspecs) {
-		int i;
 		data->refspec_nr = refspec_nr;
 		data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
 		for (i = 0; i < refspec_nr; i++)

@@ -214,6 +217,9 @@ static struct child_process *get_helper(struct transport *transport, const struc
 	strbuf_release(&buf);
 	if (debug)
 		fprintf(stderr, "Debug: Capabilities complete.\n");
+
+	for (i = 0; i < req_refspec_nr; i++)
+		set_helper_option(transport, "refspec", req_refspecs[i].src);
 	standard_options(transport);
 	return data->helper;
 }

@@ -254,7 +254,7 @@ static struct discovery *discover_refs(const char *service, int for_push)
 	struct strbuf effective_url = STRBUF_INIT;
 	struct discovery *last = last_discovery;
 	int http_ret, maybe_smart = 0;
-	struct http_get_options options;
+	struct http_get_options get_options;
 
 	if (last && !strcmp(service, last->service))
 		return last;

@@ -271,15 +271,15 @@ static struct discovery *discover_refs(const char *service, int for_push)
 		strbuf_addf(&refs_url, "service=%s", service);
 	}
 
-	memset(&options, 0, sizeof(options));
-	options.content_type = &type;
-	options.charset = &charset;
-	options.effective_url = &effective_url;
-	options.base_url = &url;
-	options.no_cache = 1;
-	options.keep_error = 1;
+	memset(&get_options, 0, sizeof(get_options));
+	get_options.content_type = &type;
+	get_options.charset = &charset;
+	get_options.effective_url = &effective_url;
+	get_options.base_url = &url;
+	get_options.no_cache = 1;
+	get_options.keep_error = 1;
 
-	http_ret = http_get_strbuf(refs_url.buf, &buffer, &options);
+	http_ret = http_get_strbuf(refs_url.buf, &buffer, &get_options);
 	switch (http_ret) {
 	case HTTP_OK:
 		break;

@@ -452,6 +452,7 @@ static void get_info_refs(char *arg)
 	if (service_name) {
 		struct argv_array argv = ARGV_ARRAY_INIT;
 		struct rpc_service *svc = select_service(service_name);
+		const char *refspec;
 
 		strbuf_addf(&buf, "application/x-git-%s-advertisement",
 			svc->name);

@@ -465,6 +466,14 @@ static void get_info_refs(char *arg)
 		argv_array_push(&argv, "--stateless-rpc");
 		argv_array_push(&argv, "--advertise-refs");
 
+		refspec = get_parameter("refspec");
+		if (refspec) {
+			struct strbuf interesting_refs = STRBUF_INIT;
+			strbuf_addstr(&interesting_refs, "--interesting-refs=");
+			strbuf_addstr(&interesting_refs, refspec);
+			argv_array_push(&argv, interesting_refs.buf);
+			strbuf_release(&interesting_refs);
+		}
 		argv_array_push(&argv, ".");
 		run_service(argv.argv, 0);
 		argv_array_clear(&argv);

@@ -52,6 +52,7 @@ static int keepalive = 5;
 static int use_sideband;
 static int advertise_refs;
 static int stateless_rpc;
+static struct string_list interesting_refspecs = STRING_LIST_INIT_DUP;
 
 static void reset_timeout(void)
 {

@@ -687,16 +688,61 @@ static void receive_needs(void)
 	free(shallows.objects);
 }
 
-/* return non-zero if the ref is hidden, otherwise 0 */
+struct refspec_data {
+	int has_star;
+	size_t prefixlen;
+	size_t suffixlen;
+};
+
+static int matches_refspec(const char *refspec, struct refspec_data *data,
+		    const char *ref)
+{
+	size_t len;
+
+	if (!data->has_star)
+		return !strcmp(refspec, ref);
+
+	if (strncmp(refspec, ref, data->prefixlen))
+		return -1;
+
+	len = strlen(refspec);
+	if (len < data->prefixlen + data->suffixlen)
+		return -1;
+
+	return strcmp(ref + (len - data->suffixlen),
+		      refspec + data->prefixlen + 1);
+}
+
+/*
+ * return non-zero if the ref is hidden or outside the provided
+ * refspecs, otherwise 0
+*/
 static int mark_our_ref(const char *refname, const char *refname_full,
 			const struct object_id *oid)
 {
 	struct object *o = lookup_unknown_object(oid->hash);
+	struct string_list_item *item;
 
 	if (ref_is_hidden(refname, refname_full)) {
 		o->flags |= HIDDEN_REF;
 		return 1;
 	}
+
+	if (interesting_refspecs.nr) {
+		int found = 0;
+		/*
+		 * TODO: this could be faster for large numbers of
+		 * refspecs by using tries or a DFA.
+		 */
+		for_each_string_list_item(item, &interesting_refspecs)
+			if (matches_refspec(item->string, item->util, refname)) {
+				found = 1;
+				break;
+			}
+		if (!found)
+			return 1;
+
+	}
 	o->flags |= OUR_REF;
 	return 0;
 }

@@ -725,7 +771,7 @@ static int send_ref(const char *refname, const struct object_id *oid,
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow no-progress"
-		" include-tag multi_ack_detailed";
+		" include-tag multi_ack_detailed interesting-refs";
 	const char *refname_nons = strip_namespace(refname);
 	struct object_id peeled;
 

@@ -820,6 +866,24 @@ static int upload_pack_config(const char *var, const char *value, void *unused)
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
+static struct refspec_data *make_refspec_data(const char *refspec)
+{
+	struct refspec_data *data;
+	const char *star;
+
+	data = xmalloc(sizeof(struct refspec_data));
+	star = strchr(refspec, '*');
+	if (star) {
+		data->has_star = 1;
+		data->prefixlen = star - refspec;
+		data->suffixlen = strlen(refspec) - (data->prefixlen + 1);
+	} else {
+		data->has_star = 0;
+	}
+
+	return data;
+}
+
 int main(int argc, char **argv)
 {
 	char *dir;

@@ -841,6 +905,19 @@ int main(int argc, char **argv)
 			advertise_refs = 1;
 			continue;
 		}
+		if (starts_with(arg, "--interesting-refs=")) {
+			struct string_list_item *item;
+
+			string_list_split(&interesting_refspecs, arg + 19,
+					  ' ', -1);
+			for_each_string_list_item(item, &interesting_refspecs) {
+				if (check_refname_format(item->string,
+							 REFNAME_REFSPEC_PATTERN))
+					die("invalid refspec %s", item->string);
+				item->util = make_refspec_data(item->string);
+			}
+			continue;
+		}
 		if (!strcmp(arg, "--stateless-rpc")) {
 			stateless_rpc = 1;
 			continue;

@@ -1010,7 +1010,21 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (transport->smart_options && !option_depth)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
-	refs = transport_get_remote_refs(transport, NULL, 0);
+	if (option_single_branch && option_branch) {
+		struct refspec branch_refspec = {0};
+
+		if (starts_with(option_branch, "refs/")) {
+			branch_refspec.src = xstrdup(option_branch);
+		} else {
+			struct strbuf buf = STRBUF_INIT;
+			strbuf_addf(&buf, "refs/heads/%s", option_branch);
+			branch_refspec.src = strbuf_detach(&buf, NULL);
+		}
+		refs = transport_get_remote_refs(transport, &branch_refspec, 1);
+		free(branch_refspec.src);
+	} else {
+		refs = transport_get_remote_refs(transport, NULL, 0);
+	}
 
 	if (refs) {
 		mapped_refs = wanted_peer_refs(refs, refspec);

@@ -38,5 +38,10 @@ test_expect_success 'fetch with refspec only fetches requested branch' '
 	)
 '
 
+test_expect_success 'single-branch clone only fetches requested branch' '
+	GIT_TRACE_PACKET="$TRASH_DIRECTORY/trace" git clone --single-branch -b master $HTTPD_URL/smart/repo.git sbc &&
+	! grep "refs/heads/another_branch" trace
+'
+
 stop_httpd
 test_done

@@ -28,6 +28,7 @@ struct helper_data {
 		signed_tags : 1,
 		check_connectivity : 1,
 		no_disconnect_req : 1,
+		refspec : 1,
 		no_private_update : 1;
 	char *export_marks;
 	char *import_marks;

@@ -114,8 +115,15 @@ static struct child_process *get_helper(struct transport *transport, const struc
 	int code;
 	int i;
 
-	if (data->helper)
+	if (data->helper) {
+		if (!data->refspec && req_refspec_nr) {
+			for (i = 0; i < req_refspec_nr; i++)
+				set_helper_option(transport, "refspec",
+						  req_refspecs[i].src);
+			data->refspec = 1;
+		}
 		return data->helper;
+	}
 
 	helper = xmalloc(sizeof(*helper));
 	child_process_init(helper);

@@ -220,6 +228,8 @@ static struct child_process *get_helper(struct transport *transport, const struc
 
 	for (i = 0; i < req_refspec_nr; i++)
 		set_helper_option(transport, "refspec", req_refspecs[i].src);
+	if (req_refspec_nr)
+		data->refspec = 1;
 	standard_options(transport);
 	return data->helper;
 }

@@ -450,9 +450,7 @@ static void get_info_refs(char *arg)
 	hdr_nocache();
 
 	if (service_name) {
-		const char *argv[] = {NULL /* service name */,
-			"--stateless-rpc", "--advertise-refs",
-			".", NULL};
+		struct argv_array argv = ARGV_ARRAY_INIT;
 		struct rpc_service *svc = select_service(service_name);
 
 		strbuf_addf(&buf, "application/x-git-%s-advertisement",

@@ -463,9 +461,13 @@ static void get_info_refs(char *arg)
 		packet_write(1, "# service=git-%s\n", svc->name);
 		packet_flush(1);
 
-		argv[0] = svc->name;
-		run_service(argv, 0);
+		argv_array_push(&argv, svc->name);
+		argv_array_push(&argv, "--stateless-rpc");
+		argv_array_push(&argv, "--advertise-refs");
 
+		argv_array_push(&argv, ".");
+		run_service(argv.argv, 0);
+		argv_array_clear(&argv);
 	} else {
 		select_getanyfile();
 		for_each_namespaced_ref(show_text_ref, &buf);