git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH v2 3/6] send-pack: demultiplex a sideband stream with status data

From
Shawn O. Pearce <spearce@spearce.org>
Date
Feb 5, 2010, 20:57 UTC
Message-ID
<1265403462-20572-4-git-send-email-spearce@spearce.org>
In-Reply-To
<1265403462-20572-1-git-send-email-spearce@spearce.org>

If the server advertises side-band-64k capability, we request it and pull the status report data out of side band #1, and let side band #2 go to our stderr. The latter channel be used by the remote side to send our user messages. This basically mirrors the side-band-64k capability in upload-pack.

Servers may choose to use side band #2 to send error messages from hook scripts that are meant for the push end user.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 builtin-send-pack.c |   66 ++++++++++++++++++++++++++++++++++++++------------
 1 files changed, 50 insertions(+), 16 deletions(-)
diff --git a/builtin-send-pack.c b/builtin-send-pack.c
index 8fffdbf..2478e18 100644
--- a/builtin-send-pack.c
+++ b/builtin-send-pack.c
@@ -372,6 +372,14 @@ static void print_helper_status(struct ref *ref)
 	strbuf_release(&buf);
 }
 
+static int sideband_demux(int in, int out, void *data)
+{
+	int *fd = data;
+	int ret = recv_sideband("send-pack", fd[0], out);
+	close(out);
+	return ret;
+}
+
 int send_pack(struct send_pack_args *args,
 	      int fd[], struct child_process *conn,
 	      struct ref *remote_refs,
@@ -382,18 +390,22 @@ int send_pack(struct send_pack_args *args,
 	struct strbuf req_buf = STRBUF_INIT;
 	struct ref *ref;
 	int new_refs;
-	int ask_for_status_report = 0;
 	int allow_deleting_refs = 0;
-	int expect_status_report = 0;
+	int status_report = 0;
+	int use_sideband = 0;
+	unsigned cmds_sent = 0;
 	int ret;
+	struct async demux;
 
 	/* Does the other end support the reporting? */
 	if (server_supports("report-status"))
-		ask_for_status_report = 1;
+		status_report = 1;
 	if (server_supports("delete-refs"))
 		allow_deleting_refs = 1;
 	if (server_supports("ofs-delta"))
 		args->use_ofs_delta = 1;
+	if (server_supports("side-band-64k"))
+		use_sideband = 1;
 
 	if (!remote_refs) {
 		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
@@ -456,28 +468,30 @@ int send_pack(struct send_pack_args *args,
 		if (!ref->deletion)
 			new_refs++;
 
-		if (!args->dry_run) {
+		if (args->dry_run) {
+			ref->status = REF_STATUS_OK;
+		} else {
 			char *old_hex = sha1_to_hex(ref->old_sha1);
 			char *new_hex = sha1_to_hex(ref->new_sha1);
 
-			if (ask_for_status_report) {
-				packet_buf_write(&req_buf, "%s %s %s%c%s",
+			if (!cmds_sent && (status_report || use_sideband)) {
+				packet_buf_write(&req_buf, "%s %s %s%c%s%s",
 					old_hex, new_hex, ref->name, 0,
-					"report-status");
-				ask_for_status_report = 0;
-				expect_status_report = 1;
+					status_report ? " report-status" : "",
+					use_sideband ? " side-band-64k" : "");
 			}
 			else
 				packet_buf_write(&req_buf, "%s %s %s",
 					old_hex, new_hex, ref->name);
+			ref->status = status_report ?
+				REF_STATUS_EXPECTING_REPORT :
+				REF_STATUS_OK;
+			cmds_sent++;
 		}
-		ref->status = expect_status_report ?
-			REF_STATUS_EXPECTING_REPORT :
-			REF_STATUS_OK;
 	}
 
 	if (args->stateless_rpc) {
-		if (!args->dry_run) {
+		if (!args->dry_run && cmds_sent) {
 			packet_buf_flush(&req_buf);
 			send_sideband(out, -1, req_buf.buf, req_buf.len, LARGE_PACKET_MAX);
 		}
@@ -487,23 +501,43 @@ int send_pack(struct send_pack_args *args,
 	}
 	strbuf_release(&req_buf);
 
-	if (new_refs && !args->dry_run) {
+	if (use_sideband && cmds_sent) {
+		memset(&demux, 0, sizeof(demux));
+		demux.proc = sideband_demux;
+		demux.data = fd;
+		demux.out = -1;
+		if (start_async(&demux))
+			die("receive-pack: unable to fork off sideband demultiplexer");
+		in = demux.out;
+	}
+
+	if (new_refs && cmds_sent) {
 		if (pack_objects(out, remote_refs, extra_have, args) < 0) {
 			for (ref = remote_refs; ref; ref = ref->next)
 				ref->status = REF_STATUS_NONE;
+			if (use_sideband)
+				finish_async(&demux);
 			return -1;
 		}
 	}
-	if (args->stateless_rpc && !args->dry_run)
+	if (args->stateless_rpc && cmds_sent)
 		packet_flush(out);
 
-	if (expect_status_report)
+	if (status_report && cmds_sent)
 		ret = receive_status(in, remote_refs);
 	else
 		ret = 0;
 	if (args->stateless_rpc)
 		packet_flush(out);
 
+	if (use_sideband && cmds_sent) {
+		if (finish_async(&demux)) {
+			error("error in sideband demultiplexer");
+			ret = -1;
+		}
+		close(demux.out);
+	}
+
 	if (ret < 0)
 		return ret;
 	for (ref = remote_refs; ref; ref = ref->next) {
-- 
1.7.0.rc1.199.g9253ab
Previous: Shawn O. PearceNext: Shawn O. Pearce
Message 4 of 14 in “receive-pack hooks over sideband”
  1. 0/6 receive-pack hooks over sidebandShawn O. Pearce, Feb 5, 2010
  2. 1/6 run-command: Allow stderr to be a caller supplied pipeShawn O. Pearce, Feb 5, 2010
  3. 2/6 run-command: support custom fd-set in asyncShawn O. Pearce, Feb 5, 2010
  4. 3/6 send-pack: demultiplex a sideband stream with status dataShawn O. Pearce, Feb 5, 2010
  5. 4/6 receive-pack: Refactor how capabilities are shown to the clientShawn O. Pearce, Feb 5, 2010
  6. 5/6 receive-pack: Wrap status reports inside side-band-64kShawn O. Pearce, Feb 5, 2010
  7. Junio C HamanoFeb 5, 2010
  8. Shawn O. PearceFeb 5, 2010
  9. Junio C HamanoFeb 5, 2010
  10. 6/6 receive-pack: Send hook output over side band #2Shawn O. Pearce, Feb 5, 2010
  11. Larry D'AnnaFeb 9, 2010
  12. Shawn O. PearceFeb 9, 2010
  13. Larry D'AnnaFeb 9, 2010
  14. Larry D'AnnaFeb 9, 2010

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.