Track the last session for a client and add a flag to switch-client and

a key binding (L) to move a client back to its last session.

cmd-new-session.c

@@ -279,9 +279,17 @@ cmd_new_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 	if (!detached) {
 		if (ctx->cmdclient != NULL) {
 			server_write_client(ctx->cmdclient, MSG_READY, NULL, 0);
+			if (ctx->cmdclient->session != NULL) {
+				session_index(ctx->cmdclient->session,
+				    &ctx->cmdclient->last_session);
+			}
 			ctx->cmdclient->session = s;
 			server_redraw_client(ctx->cmdclient);
 		} else {
+			if (ctx->curclient->session != NULL) {
+				session_index(ctx->curclient->session,
+				    &ctx->curclient->last_session);
+			}
 			ctx->curclient->session = s;
 			server_redraw_client(ctx->curclient);
 		}

cmd-switch-client.c

@@ -36,13 +36,14 @@ size_t	cmd_switch_client_print(struct cmd *, char *, size_t);
 struct cmd_switch_client_data {
 	char	*name;
 	char	*target;
+	int      flag_last;
 	int	 flag_next;
 	int	 flag_previous;
 };
 
 const struct cmd_entry cmd_switch_client_entry = {
 	"switch-client", "switchc",
-	"[-np] [-c target-client] [-t target-session]",
+	"[-lnp] [-c target-client] [-t target-session]",
 	0, "",
 	cmd_switch_client_init,
 	cmd_switch_client_parse,
@@ -59,6 +60,7 @@ cmd_switch_client_init(struct cmd *self, int key)
 	self->data = data = xmalloc(sizeof *data);
 	data->name = NULL;
 	data->target = NULL;
+	data->flag_last = 0;
 	data->flag_next = 0;
 	data->flag_previous = 0;
 
@@ -69,6 +71,9 @@ cmd_switch_client_init(struct cmd *self, int key)
 	case ')':
 		data->flag_next = 1;
 		break;
+	case 'L':
+		data->flag_last = 1;
+		break;
 	}
 }
 
@@ -81,28 +86,36 @@ cmd_switch_client_parse(struct cmd *self, int argc, char **argv, char **cause)
 	self->entry->init(self, KEYC_NONE);
 	data = self->data;
 
-	while ((opt = getopt(argc, argv, "c:t:")) != -1) {
+	while ((opt = getopt(argc, argv, "c:lnpt:")) != -1) {
 		switch (opt) {
 		case 'c':
 			if (data->name == NULL)
 				data->name = xstrdup(optarg);
 			break;
+		case 'l':
+			if (data->flag_next || data->flag_previous ||
+			    data->target != NULL)
+				goto usage;
+			data->flag_last = 1;
+			break;
+		case 'n':
+			if (data->flag_previous || data->flag_last ||
+			    data->target != NULL)
+				goto usage;
+			data->flag_next = 1;
+			break;
+		case 'p':
+			if (data->flag_next || data->flag_last ||
+			    data->target != NULL)
+				goto usage;
+			data->flag_next = 1;
+			break;
 		case 't':
 			if (data->flag_next || data->flag_previous)
 				goto usage;
 			if (data->target == NULL)
 				data->target = xstrdup(optarg);
 			break;
-		case 'n':
-			if (data->flag_previous || data->target != NULL)
-				goto usage;
-			data->flag_next = 1;
-			break;
-		case 'p':
-			if (data->flag_next || data->target != NULL)
-				goto usage;
-			data->flag_next = 1;
-			break;
 		default:
 			goto usage;
 		}
@@ -134,6 +147,7 @@ cmd_switch_client_exec(struct cmd *self, struct cmd_ctx *ctx)
 	if ((c = cmd_find_client(ctx, data->name)) == NULL)
 		return (-1);
 
+	s = NULL;
 	if (data->flag_next) {
 		if ((s = session_next_session(c->session)) == NULL) {
 			ctx->error(ctx, "can't find next session");
@@ -144,11 +158,21 @@ cmd_switch_client_exec(struct cmd *self, struct cmd_ctx *ctx)
 			ctx->error(ctx, "can't find previous session");
 			return (-1);
 		}
+	} else if (data->flag_last) {
+		if (c->last_session != UINT_MAX &&
+		    c->last_session < ARRAY_LENGTH(&sessions))
+			s = ARRAY_ITEM(&sessions, c->last_session);
+		if (s == NULL) {
+			ctx->error(ctx, "can't find last session");
+			return (-1);
+		}
 	} else
 		s = cmd_find_session(ctx, data->target);
-
 	if (s == NULL)
 		return (-1);
+
+	if (c->session != NULL)
+		session_index(c->session, &c->last_session);
 	c->session = s;
 
 	recalculate_sizes();
@@ -179,6 +203,8 @@ cmd_switch_client_print(struct cmd *self, char *buf, size_t len)
 	off += xsnprintf(buf, len, "%s", self->entry->name);
 	if (data == NULL)
 		return (off);
+	if (off < len && data->flag_last)
+		off += xsnprintf(buf + off, len - off, "%s", " -l");
 	if (off < len && data->flag_next)
 		off += xsnprintf(buf + off, len - off, "%s", " -n");
 	if (off < len && data->flag_previous)

key-bindings.c

@@ -128,6 +128,7 @@ key_bindings_init(void)
 		{ '=', 			  0, &cmd_choose_buffer_entry },
 		{ '?', 			  0, &cmd_list_keys_entry },
 		{ 'D',			  0, &cmd_choose_client_entry },
+		{ 'L',			  0, &cmd_switch_client_entry },
 		{ '[', 			  0, &cmd_copy_mode_entry },
 		{ '\'',			  0, &cmd_command_prompt_entry },
 		{ '\002', /* C-b */	  0, &cmd_send_prefix_entry },

server-client.c

@@ -78,6 +78,7 @@ server_client_create(int fd)
 	c->title = NULL;
 
 	c->session = NULL;
+	c->last_session = UINT_MAX;
 	c->tty.sx = 80;
 	c->tty.sy = 24;
 

server-fn.c

@@ -399,6 +399,7 @@ server_destroy_session(struct session *s)
 			c->session = NULL;
 			c->flags |= CLIENT_EXIT;
 		} else {
+			c->last_session = UINT_MAX;
 			c->session = s_new;
 			server_redraw_client(c);
 		}

tmux.1

@@ -282,6 +282,8 @@ Briefly display pane indexes.
 Force redraw of the attached client.
 .It s
 Select a new session for the attached client interactively.
+.It L
+Switch the attached client back to the last session.
 .It t
 Show the time.
 .It w
@@ -662,7 +664,7 @@ Suspend a client by sending
 .Dv SIGTSTP
 (tty stop).
 .It Xo Ic switch-client
-.Op Fl np
+.Op Fl lnp
 .Op Fl c Ar target-client
 .Op Fl t Ar target-session
 .Xc
@@ -672,10 +674,12 @@ Switch the current session for client
 to
 .Ar target-session .
 If
+.Fl l,
 .Fl n
 or
 .Fl p
-is used, the client is moved to the next or previous session respectively.
+is used, the client is moved to the last, next or previous session
+respectively.
 .El
 .Sh WINDOWS AND PANES
 A

tmux.h

@@ -1155,6 +1155,7 @@ struct client {
 	struct mode_key_data prompt_mdata;
 
 	struct session	*session;
+	u_int            last_session;
 
 	int		 references;
 };