[PATCH 05/10] serve: advertise trace2 SID in v2 capabilities

[Josh Steadmon <steadmon@google.com>]

When trace2 is enabled and trace2.advertiseSID is true, advertise the
server's trace2 session ID for all protocol v2 connections via the new
trace2-sid capability.

Signed-off-by: Josh Steadmon <steadmon@google.com>
---
 serve.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/serve.c b/serve.c
index f6341206c4..6ad73d69ab 100644
--- a/serve.c
+++ b/serve.c
@@ -7,6 +7,9 @@
 #include "ls-refs.h"
 #include "serve.h"
 #include "upload-pack.h"
+#include "trace2/tr2_sid.h"
+
+static int advertise_trace2_sid;
 
 static int always_advertise(struct repository *r,
 			    struct strbuf *value)
@@ -30,6 +33,15 @@ static int object_format_advertise(struct repository *r,
 	return 1;
 }
 
+static int trace2_advertise(struct repository *r, struct strbuf *value)
+{
+	if (!advertise_trace2_sid || !trace2_is_enabled())
+		return 0;
+	if (value)
+		strbuf_addstr(value, tr2_sid_get());
+	return 1;
+}
+
 struct protocol_capability {
 	/*
 	 * The name of the capability.  The server uses this name when
@@ -66,6 +78,7 @@ static struct protocol_capability capabilities[] = {
 	{ "fetch", upload_pack_advertise, upload_pack_v2 },
 	{ "server-option", always_advertise, NULL },
 	{ "object-format", object_format_advertise, NULL },
+	{ "trace2-sid", trace2_advertise, NULL },
 };
 
 static void advertise_capabilities(void)
@@ -261,6 +274,8 @@ static int process_request(void)
 /* Main serve loop for protocol version 2 */
 void serve(struct serve_options *options)
 {
+	git_config_get_bool("trace2.advertisesid", &advertise_trace2_sid);
+
 	if (options->advertise_capabilities || !options->stateless_rpc) {
 		/* serve by default supports v2 */
 		packet_write_fmt(1, "version 2\n");
-- 
2.29.1.341.ge80a0c044ae-goog