Add a flag to move-window to renumber the windows in a session (closing

any gaps) and add an option to do this automatically each time a window
is killed. From Thomas Adam.

cmd-move-window.c

@@ -30,8 +30,8 @@ int	cmd_move_window_exec(struct cmd *, struct cmd_ctx *);
 
 const struct cmd_entry cmd_move_window_entry = {
 	"move-window", "movew",
-	"dks:t:", 0, 0,
-	"[-dk] " CMD_SRCDST_WINDOW_USAGE,
+	"dkrs:t:", 0, 0,
+	"[-dkr] " CMD_SRCDST_WINDOW_USAGE,
 	0,
 	NULL,
 	NULL,
@@ -42,11 +42,22 @@ int
 cmd_move_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 {
 	struct args	*args = self->args;
-	struct session	*src, *dst;
+	struct session	*src, *dst, *s;
 	struct winlink	*wl;
 	char		*cause;
 	int		 idx, kflag, dflag;
 
+	if ((s = ctx->curclient->session) == NULL)
+		return (-1);
+
+	if (args_has(args, 'r'))
+	{
+		session_renumber_windows(s);
+		recalculate_sizes();
+
+		return (0);
+	}
+
 	if ((wl = cmd_find_window(ctx, args_get(args, 's'), &src)) == NULL)
 		return (-1);
 	if ((idx = cmd_find_index(ctx, args_get(args, 't'), &dst)) == -2)

options-table.c

@@ -274,6 +274,11 @@ const struct options_table_entry session_options_table[] = {
 	  .default_num = KEYC_NONE,
 	},
 
+	{ .name = "renumber-windows",
+	  .type = OPTIONS_TABLE_FLAG,
+	  .default_num = 0
+	},
+
 	{ .name = "repeat-time",
 	  .type = OPTIONS_TABLE_NUMBER,
 	  .minimum = 0,

server-fn.c

@@ -263,6 +263,9 @@ server_kill_window(struct window *w)
 			} else
 				server_redraw_session_group(s);
 		}
+
+		if (options_get_number(&s->options, "renumber-windows"))
+			session_renumber_windows(s);
 	}
 }
 

session.c

@@ -591,3 +591,49 @@ session_group_synchronize1(struct session *target, struct session *s)
 		winlink_remove(&old_windows, wl);
 	}
 }
+
+/* Renumber the windows across winlinks attached to a specific session. */
+void
+session_renumber_windows(struct session *s)
+{
+	struct winlink		*wl, *wl1, *wl_new;
+	struct winlinks		 old_wins;
+	struct winlink_stack	 old_lastw;
+	int			 new_idx, new_curw_idx;
+
+	/* Save and replace old window list. */
+	memcpy(&old_wins, &s->windows, sizeof old_wins);
+	RB_INIT(&s->windows);
+
+	/* Start renumbering from the base-index if it's set. */
+	new_idx = options_get_number(&s->options, "base-index");
+	new_curw_idx = 0;
+
+	/* Go through the winlinks and assign new indexes. */
+	RB_FOREACH(wl, winlinks, &old_wins) {
+		wl_new = winlink_add(&s->windows, new_idx);
+		winlink_set_window(wl_new, wl->window);
+		wl_new->flags |= wl->flags & WINLINK_ALERTFLAGS;
+
+		if (wl == s->curw)
+			new_curw_idx = wl_new->idx;
+
+		new_idx++;
+	}
+
+	/* Fix the stack of last windows now. */
+	memcpy(&old_lastw, &s->lastw, sizeof old_lastw);
+	TAILQ_INIT(&s->lastw);
+	TAILQ_FOREACH(wl, &old_lastw, sentry) {
+		wl_new = winlink_find_by_index(&s->windows, wl->idx);
+		if (wl_new != NULL)
+			TAILQ_INSERT_TAIL(&s->lastw, wl_new, sentry);
+	}
+
+	/* Set the current window. */
+	s->curw = winlink_find_by_index(&s->windows, new_curw_idx);
+
+	/* Free the old winlinks (reducing window references too). */
+	RB_FOREACH_SAFE(wl, winlinks, &old_wins, wl1)
+		winlink_remove(&old_wins, wl);
+}

tmux.1

@@ -1258,7 +1258,7 @@ and
 .Ar dst-pane
 may belong to the same window.
 .It Xo Ic move-window
-.Op Fl dk
+.Op Fl rdk
 .Op Fl s Ar src-window
 .Op Fl t Ar dst-window
 .Xc
@@ -1269,6 +1269,12 @@ except the window at
 .Ar src-window
 is moved to
 .Ar dst-window .
+With
+.Fl r ,
+all windows in the session are renumbered in sequential order, respecting
+the
+.Ic base-index
+option.
 .It Xo Ic new-window
 .Op Fl adkP
 .Op Fl c Ar start-directory
@@ -2122,6 +2128,15 @@ Set the pane border colour for panes aside from the active pane.
 Set the key accepted as a prefix key.
 .It Ic prefix2 Ar key
 Set a secondary key accepted as a prefix key.
+.It Xo Ic renumber-windows
+.Op Ic on | off
+.Xc
+If on, when a window is closed in a session, automatically renumber the other
+windows in numerical order.
+This respects the
+.Ic base-index
+option if it has been set.
+If off, do not renumber the windows.
 .It Ic repeat-time Ar time
 Allow multiple commands to be entered without pressing the prefix-key again
 in the specified

tmux.h

@@ -2116,6 +2116,7 @@ void		 session_group_remove(struct session *);
 void		 session_group_synchronize_to(struct session *);
 void		 session_group_synchronize_from(struct session *);
 void		 session_group_synchronize1(struct session *, struct session *);
+void		 session_renumber_windows(struct session *);
 
 /* utf8.c */
 void	utf8_build(void);