ls-remote: pass ref prefixes when requesting a remote's refs

Construct an argv_array of ref prefixes based on the patterns supplied
via the command line and pass them to 'transport_get_remote_refs()' to
be used when communicating protocol v2 so that the server can limit the
ref advertisement based on those prefixes.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/ls-remote.c

@@ -2,6 +2,7 @@
 #include "cache.h"
 #include "transport.h"
 #include "remote.h"
+#include "refs.h"
 
 static const char * const ls_remote_usage[] = {
 	N_("git ls-remote [--heads] [--tags] [--refs] [--upload-pack=<exec>]\n"
@@ -43,6 +44,7 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 	int show_symref_target = 0;
 	const char *uploadpack = NULL;
 	const char **pattern = NULL;
+	struct argv_array ref_prefixes = ARGV_ARRAY_INIT;
 
 	struct remote *remote;
 	struct transport *transport;
@@ -74,8 +76,17 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 	if (argc > 1) {
 		int i;
 		pattern = xcalloc(argc, sizeof(const char *));
-		for (i = 1; i < argc; i++)
+		for (i = 1; i < argc; i++) {
+			const char *glob;
 			pattern[i - 1] = xstrfmt("*/%s", argv[i]);
+
+			glob = strchr(argv[i], '*');
+			if (glob)
+				argv_array_pushf(&ref_prefixes, "%.*s",
+						 (int)(glob - argv[i]), argv[i]);
+			else
+				expand_ref_prefix(&ref_prefixes, argv[i]);
+		}
 	}
 
 	remote = remote_get(dest);
@@ -96,7 +107,7 @@ 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, NULL);
+	ref = transport_get_remote_refs(transport, &ref_prefixes);
 	if (transport_disconnect(transport))
 		return 1;
 

refs.c

@@ -13,6 +13,7 @@
 #include "tag.h"
 #include "submodule.h"
 #include "worktree.h"
+#include "argv-array.h"
 
 /*
  * List of all available backends
@@ -501,6 +502,19 @@ int refname_match(const char *abbrev_name, const char *full_name)
 	return 0;
 }
 
+/*
+ * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
+ * the results to 'prefixes'
+ */
+void expand_ref_prefix(struct argv_array *prefixes, const char *prefix)
+{
+	const char **p;
+	int len = strlen(prefix);
+
+	for (p = ref_rev_parse_rules; *p; p++)
+		argv_array_pushf(prefixes, *p, len, prefix);
+}
+
 /*
  * *string and *len will only be substituted, and *string returned (for
  * later free()ing) if the string passed in is a magic short-hand form

refs.h

@@ -139,6 +139,13 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
  */
 int refname_match(const char *abbrev_name, const char *full_name);
 
+/*
+ * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
+ * the results to 'prefixes'
+ */
+struct argv_array;
+void expand_ref_prefix(struct argv_array *prefixes, const char *prefix);
+
 int expand_ref(const char *str, int len, struct object_id *oid, char **ref);
 int dwim_ref(const char *str, int len, struct object_id *oid, char **ref);
 int dwim_log(const char *str, int len, struct object_id *oid, char **ref);

t/t5702-protocol-v2.sh

@@ -32,6 +32,19 @@ test_expect_success 'list refs with git:// using protocol v2' '
 	test_cmp actual expect
 '
 
+test_expect_success 'ref advertisment is filtered with ls-remote using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote "$GIT_DAEMON_URL/parent" master >actual &&
+
+	cat >expect <<-EOF &&
+	$(git -C "$daemon_parent" rev-parse refs/heads/master)$(printf "\t")refs/heads/master
+	EOF
+
+	test_cmp actual expect
+'
+
 stop_git_daemon
 
 # Test protocol v2 with 'file://' transport
@@ -54,4 +67,17 @@ test_expect_success 'list refs with file:// using protocol v2' '
 	test_cmp actual expect
 '
 
+test_expect_success 'ref advertisment is filtered with ls-remote using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote "file://$(pwd)/file_parent" master >actual &&
+
+	cat >expect <<-EOF &&
+	$(git -C file_parent rev-parse refs/heads/master)$(printf "\t")refs/heads/master
+	EOF
+
+	test_cmp actual expect
+'
+
 test_done