From 738489f2bb6bc28b6375c367b8313e376b2de5b1 Mon Sep 17 00:00:00 2001
From: Tiago Cunha <tcunha@gmx.com>
Date: Mon, 2 Nov 2009 21:32:52 +0000
Subject: [PATCH] Sync OpenBSD patchset 472:

If any client currently displaying a window pane has more than 1 KB of output
buffered, don't accept any further data from the process running in the pane.

This makes tmux much more responsive when flooded with output, although other
buffers can still have an impact when running remotely.

Prompted by a query from Ranganathan Sankaralingam.
---
 server-window.c | 29 +++++++++++++++++++++++++++--
 tmux.h          |  5 ++++-
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/server-window.c b/server-window.c
index 0c57b990..91b91bce 100644
--- a/server-window.c
+++ b/server-window.c
@@ -1,4 +1,4 @@
-/* $Id: server-window.c,v 1.2 2009-10-28 23:14:15 tcunha Exp $ */
+/* $Id: server-window.c,v 1.3 2009-11-02 21:32:51 tcunha Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -22,6 +22,7 @@
 
 #include "tmux.h"
 
+int	server_window_backoff(struct window_pane *);
 int	server_window_check_bell(struct session *, struct window *);
 int	server_window_check_activity(struct session *, struct window *);
 int	server_window_check_content(
@@ -44,7 +45,9 @@ server_window_prepare(void)
 		TAILQ_FOREACH(wp, &w->panes, entry) {	
 			if (wp->fd == -1)
 				continue;
-			events = POLLIN;
+			events = 0;
+			if (!server_window_backoff(wp))
+				events |= POLLIN;
 			if (BUFFER_USED(wp->out) > 0)
 				events |= POLLOUT;
 			server_poll_add(
@@ -61,6 +64,28 @@ server_window_prepare(void)
 	}
 }
 
+/* Check if this window should suspend reading. */
+int
+server_window_backoff(struct window_pane *wp)
+{
+	struct client	*c;
+	u_int		 i;
+
+	if (!window_pane_visible(wp))
+		return (0);
+
+	for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
+		c = ARRAY_ITEM(&clients, i);
+		if (c == NULL || c->session == NULL)
+			continue;
+		if (c->session->curw->window != wp->window)
+			continue;
+		if (BUFFER_USED(c->tty.out) > BACKOFF_THRESHOLD)
+			return (1);
+	}
+	return (0);
+}
+
 /* Process a single window pane event. */
 void
 server_window_callback(int fd, int events, void *data)
diff --git a/tmux.h b/tmux.h
index d54ee216..01fc1bb8 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1,4 +1,4 @@
-/* $Id: tmux.h,v 1.489 2009-10-28 23:14:15 tcunha Exp $ */
+/* $Id: tmux.h,v 1.490 2009-11-02 21:32:52 tcunha Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -63,6 +63,9 @@ extern char   **environ;
 /* Maximum poll timeout (when attached). */
 #define POLL_TIMEOUT 50
 
+/* Maximum data to buffer for output before suspending reading from panes. */
+#define BACKOFF_THRESHOLD 1024
+
 /*
  * Maximum sizes of strings in message data. Don't forget to bump
  * PROTOCOL_VERSION if any of these change!