Add support for the xterm(1) title stack, from Brad Town, GitHub issue

1075.

input.c

@@ -1693,12 +1693,33 @@ input_csi_dispatch_winops(struct input_ctx *ictx)
 			/* FALLTHROUGH */
 		case 9:
 		case 10:
-		case 22:
-		case 23:
 			m++;
 			if (input_get(ictx, m, 0, -1) == -1)
 				return;
 			break;
+		case 22:
+			m++;
+			switch (input_get(ictx, m, 0, -1)) {
+			case -1:
+				return;
+			case 0:
+			case 2:
+				screen_push_title(ictx->ctx.s);
+				break;
+			}
+			break;
+		case 23:
+			m++;
+			switch (input_get(ictx, m, 0, -1)) {
+			case -1:
+				return;
+			case 0:
+			case 2:
+				screen_pop_title(ictx->ctx.s);
+				server_status_window(ictx->wp->window);
+				break;
+			}
+			break;
 		case 18:
 			input_reply(ictx, "\033[8;%u;%ut", wp->sy, wp->sx);
 			break;

screen.c

@@ -25,17 +25,44 @@
 
 #include "tmux.h"
 
+struct screen_title_entry {
+	char				*text;
+
+	TAILQ_ENTRY(screen_title_entry)	 entry;
+};
+TAILQ_HEAD(screen_titles, screen_title_entry);
+
 static void	screen_resize_x(struct screen *, u_int);
 static void	screen_resize_y(struct screen *, u_int);
 
 static void	screen_reflow(struct screen *, u_int);
 
+/* Free titles stack. */
+static void
+screen_free_titles(struct screen *s)
+{
+	struct screen_title_entry	*title_entry;
+
+	if (s->titles == NULL)
+		return;
+
+	while ((title_entry = TAILQ_FIRST(s->titles)) != NULL) {
+		TAILQ_REMOVE(s->titles, title_entry, entry);
+		free(title_entry->text);
+		free(title_entry);
+	}
+
+	free(s->titles);
+	s->titles = NULL;
+}
+
 /* Create a new screen. */
 void
 screen_init(struct screen *s, u_int sx, u_int sy, u_int hlimit)
 {
 	s->grid = grid_create(sx, sy, hlimit);
 	s->title = xstrdup("");
+	s->titles = NULL;
 
 	s->cstyle = 0;
 	s->ccolour = xstrdup("");
@@ -61,6 +88,7 @@ screen_reinit(struct screen *s)
 	grid_clear_lines(s->grid, s->grid->hsize, s->grid->sy, 8);
 
 	screen_clear_selection(s);
+	screen_free_titles(s);
 }
 
 /* Destroy a screen. */
@@ -70,7 +98,10 @@ screen_free(struct screen *s)
 	free(s->tabs);
 	free(s->title);
 	free(s->ccolour);
+
 	grid_destroy(s->grid);
+
+	screen_free_titles(s);
 }
 
 /* Reset tabs to default, eight spaces apart. */
@@ -111,6 +142,43 @@ screen_set_title(struct screen *s, const char *title)
 	utf8_stravis(&s->title, title, VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL);
 }
 
+/* Push the current title onto the stack. */
+void
+screen_push_title(struct screen *s)
+{
+	struct screen_title_entry *title_entry;
+
+	if (s->titles == NULL) {
+		s->titles = xmalloc(sizeof *s->titles);
+		TAILQ_INIT(s->titles);
+	}
+	title_entry = xmalloc(sizeof *title_entry);
+	title_entry->text = xstrdup(s->title);
+	TAILQ_INSERT_HEAD(s->titles, title_entry, entry);
+}
+
+/*
+ * Pop a title from the stack and set it as the screen title. If the stack is
+ * empty, do nothing.
+ */
+void
+screen_pop_title(struct screen *s)
+{
+	struct screen_title_entry *title_entry;
+
+	if (s->titles == NULL)
+		return;
+
+	title_entry = TAILQ_FIRST(s->titles);
+	if (title_entry != NULL) {
+		screen_set_title(s, title_entry->text);
+
+		TAILQ_REMOVE(s->titles, title_entry, entry);
+		free(title_entry->text);
+		free(title_entry);
+	}
+}
+
 /* Resize screen. */
 void
 screen_resize(struct screen *s, u_int sx, u_int sy, int reflow)

tmux.h

@@ -660,8 +660,10 @@ struct screen_sel {
 };
 
 /* Virtual screen. */
+struct screen_titles;
 struct screen {
 	char			*title;
+	struct screen_titles	*titles;
 
 	struct grid		*grid;		/* grid data */
 
@@ -2082,6 +2084,8 @@ void	 screen_reset_tabs(struct screen *);
 void	 screen_set_cursor_style(struct screen *, u_int);
 void	 screen_set_cursor_colour(struct screen *, const char *);
 void	 screen_set_title(struct screen *, const char *);
+void	 screen_push_title(struct screen *);
+void	 screen_pop_title(struct screen *);
 void	 screen_resize(struct screen *, u_int, u_int, int);
 void	 screen_set_selection(struct screen *,
 	     u_int, u_int, u_int, u_int, u_int, struct grid_cell *);