If timing between keys is less than (by default) 1 millisecond, assume

the text is being pasted. assume-paste-time option changes the value (0
disables). Based on a diff from Marcin Kulik.

options-table.c

@@ -91,6 +91,13 @@ const struct options_table_entry server_options_table[] = {
 
 /* Session options. */
 const struct options_table_entry session_options_table[] = {
+	{ .name = "assume-paste-time",
+	  .type = OPTIONS_TABLE_NUMBER,
+	  .minimum = 0,
+	  .maximum = INT_MAX,
+	  .default_num = 1,
+	},
+
 	{ .name = "base-index",
 	  .type = OPTIONS_TABLE_NUMBER,
 	  .minimum = 0,

server-client.c

@@ -34,6 +34,7 @@ void	server_client_check_exit(struct client *);
 void	server_client_check_redraw(struct client *);
 void	server_client_set_title(struct client *);
 void	server_client_reset_state(struct client *);
+int	server_client_assume_paste(struct session *);
 
 int	server_client_msg_dispatch(struct client *);
 void	server_client_msg_command(struct client *, struct msg_command_data *);
@@ -325,6 +326,22 @@ server_client_check_mouse(struct client *c, struct window_pane *wp)
 	window_pane_mouse(wp, c->session, m);
 }
 
+/* Is this fast enough to probably be a paste? */
+int
+server_client_assume_paste(struct session *s)
+{
+	struct timeval	tv;
+	u_int		t;
+
+	if ((t = options_get_number(&s->options, "assume-paste-time")) == 0)
+		return 0;
+
+	timersub(&s->activity_time, &s->last_activity_time, &tv);
+	if (tv.tv_sec == 0 && tv.tv_usec < t * 1000)
+		return 1;
+	return 0;
+}
+
 /* Handle data key input from client. */
 void
 server_client_handle_key(struct client *c, int key)
@@ -334,7 +351,7 @@ server_client_handle_key(struct client *c, int key)
 	struct window_pane	*wp;
 	struct timeval		 tv;
 	struct key_binding	*bd;
-	int		      	 xtimeout, isprefix;
+	int		      	 xtimeout, isprefix, ispaste;
 
 	/* Check the client is good to accept input. */
 	if ((c->flags & (CLIENT_DEAD|CLIENT_SUSPENDED)) != 0)
@@ -346,6 +363,9 @@ server_client_handle_key(struct client *c, int key)
 	/* Update the activity timer. */
 	if (gettimeofday(&c->activity_time, NULL) != 0)
 		fatal("gettimeofday failed");
+
+	memcpy(&s->last_activity_time, &s->activity_time,
+	    sizeof s->last_activity_time);
 	memcpy(&s->activity_time, &c->activity_time, sizeof s->activity_time);
 
 	w = c->session->curw->window;
@@ -382,25 +402,31 @@ server_client_handle_key(struct client *c, int key)
 	}
 
 	/* Is this a prefix key? */
-	if (key == options_get_number(&c->session->options, "prefix"))
+	if (key == options_get_number(&s->options, "prefix"))
 		isprefix = 1;
-	else if (key == options_get_number(&c->session->options, "prefix2"))
+	else if (key == options_get_number(&s->options, "prefix2"))
 		isprefix = 1;
 	else
 		isprefix = 0;
 
+	/* Treat prefix as a regular key when pasting is detected. */
+	ispaste = server_client_assume_paste(s);
+	if (ispaste)
+		isprefix = 0;
+
 	/* No previous prefix key. */
 	if (!(c->flags & CLIENT_PREFIX)) {
-		if (isprefix)
+		if (isprefix) {
 			c->flags |= CLIENT_PREFIX;
-		else {
+			return;
-			/* Try as a non-prefix key binding. */
-			if ((bd = key_bindings_lookup(key)) == NULL) {
-				if (!(c->flags & CLIENT_READONLY))
-					window_pane_key(wp, c->session, key);
-			} else
-				key_bindings_dispatch(bd, c);
 		}
+
+		/* Try as a non-prefix key binding. */
+		if (ispaste || (bd = key_bindings_lookup(key)) == NULL) {
+			if (!(c->flags & CLIENT_READONLY))
+				window_pane_key(wp, s, key);
+		} else
+			key_bindings_dispatch(bd, c);
 		return;
 	}
 
@@ -413,7 +439,7 @@ server_client_handle_key(struct client *c, int key)
 			if (isprefix)
 				c->flags |= CLIENT_PREFIX;
 			else if (!(c->flags & CLIENT_READONLY))
-				window_pane_key(wp, c->session, key);
+				window_pane_key(wp, s, key);
 		}
 		return;
 	}
@@ -424,12 +450,12 @@ server_client_handle_key(struct client *c, int key)
 		if (isprefix)
 			c->flags |= CLIENT_PREFIX;
 		else if (!(c->flags & CLIENT_READONLY))
-			window_pane_key(wp, c->session, key);
+			window_pane_key(wp, s, key);
 		return;
 	}
 
 	/* If this key can repeat, reset the repeat flags and timer. */
-	xtimeout = options_get_number(&c->session->options, "repeat-time");
+	xtimeout = options_get_number(&s->options, "repeat-time");
 	if (xtimeout != 0 && bd->can_repeat) {
 		c->flags |= CLIENT_PREFIX|CLIENT_REPEAT;
 

tmux.1

@@ -2044,6 +2044,13 @@ interactive menu when required.
 .Pp
 Available session options are:
 .Bl -tag -width Ds
+.It Ic assume-paste-time Ar milliseconds
+If keys are entered faster than one in
+.Ar milliseconds ,
+they are assumed to have been pasted rather than typed and
+.Nm
+key bindings are not processed.
+The default is one millisecond and zero disables.
 .It Ic base-index Ar index
 Set the base index from which an unused index should be searched when a new
 window is created.

tmux.h

@@ -1095,6 +1095,7 @@ struct session {
 
 	struct timeval	 creation_time;
 	struct timeval	 activity_time;
+	struct timeval	 last_activity_time;
 
 	u_int		 sx;
 	u_int		 sy;
@@ -1707,7 +1708,6 @@ char		*paste_print(struct paste_buffer *, size_t);
 void		 paste_send_pane(struct paste_buffer *, struct window_pane *,
 		     const char *, int);
 
-
 /* clock.c */
 extern const char clock_table[14][5][5];
 void		 clock_draw(struct screen_write_ctx *, int, int);