Add push-default and pop-default in styles to change the default colours

and attributes and use them to restore the previous behaviour of
window-status-style being the default for window-status-format in the
status line. From John Drouhard in GitHub issue 1912.

format-draw.c

@@ -513,8 +513,8 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 	int			 focus_start = -1, focus_end = -1;
 	int			 list_state = -1, fill = -1;
 	enum style_align	 list_align = STYLE_ALIGN_DEFAULT;
-	struct grid_cell	 gc;
-	struct style		 sy;
+	struct grid_cell	 gc, current_default;
+	struct style		 sy, saved_sy;
 	struct utf8_data	*ud = &sy.gc.data;
 	const char		*cp, *end;
 	enum utf8_state		 more;
@@ -523,7 +523,8 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 	struct format_ranges	 frs;
 	struct style_range	*sr;
 
-	style_set(&sy, base);
+	memcpy(&current_default, base, sizeof current_default);
+	style_set(&sy, &current_default);
 	TAILQ_INIT(&frs);
 	log_debug("%s: %s", __func__, expanded);
 
@@ -535,7 +536,7 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 	for (i = 0; i < TOTAL; i++) {
 		screen_init(&s[i], size, 1, 0);
 		screen_write_start(&ctx[i], NULL, &s[i]);
-		screen_write_clearendofline(&ctx[i], base->bg);
+		screen_write_clearendofline(&ctx[i], current_default.bg);
 		width[i] = 0;
 	}
 
@@ -581,7 +582,8 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 			goto out;
 		}
 		tmp = xstrndup(cp + 2, end - (cp + 2));
-		if (style_parse(&sy, base, tmp) != 0) {
+		style_copy(&saved_sy, &sy);
+		if (style_parse(&sy, &current_default, tmp) != 0) {
 			log_debug("%s: invalid style '%s'", __func__, tmp);
 			free(tmp);
 			cp = end + 1;
@@ -595,6 +597,15 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 		if (sy.fill != 8)
 			fill = sy.fill;
 
+		/* If this style pushed or popped the default, update it. */
+		if (sy.default_type == STYLE_DEFAULT_PUSH) {
+			memcpy(&current_default, &saved_sy.gc, sizeof current_default);
+			sy.default_type = STYLE_DEFAULT_BASE;
+		} else if (sy.default_type == STYLE_DEFAULT_POP) {
+			memcpy(&current_default, base, sizeof current_default);
+			sy.default_type = STYLE_DEFAULT_BASE;
+		}
+
 		/* Check the list state. */
 		switch (sy.list) {
 		case STYLE_LIST_ON:

options-table.c

@@ -92,7 +92,9 @@ static const char *options_table_window_size_list[] = {
 				"}" \
 			"}" \
 		"]" \
+		"#[push-default]" \
 		"#{T:window-status-format}" \
+		"#[pop-default]" \
 		"#[norange default]" \
 		"#{?window_end_flag,,#{window-status-separator}}" \
 	"," \
@@ -117,7 +119,9 @@ static const char *options_table_window_size_list[] = {
 				"}" \
 			"}" \
 		"]" \
+		"#[push-default]" \
 		"#{T:window-status-current-format}" \
+		"#[pop-default]" \
 		"#[norange list=on default]" \
 		"#{?window_end_flag,,#{window-status-separator}}" \
 	"}" \

style.c

@@ -36,13 +36,15 @@ static struct style style_default = {
 	STYLE_ALIGN_DEFAULT,
 	STYLE_LIST_OFF,
 
-	STYLE_RANGE_NONE, 0
+	STYLE_RANGE_NONE, 0,
+
+	STYLE_DEFAULT_BASE
 };
 
 /*
- * Parse an embedded style of the form "fg=colour,bg=colour,bright,...".
- * Note that this adds onto the given style, so it must have been initialized
- * alredy.
+ * Parse an embedded style of the form "fg=colour,bg=colour,bright,...".  Note
+ * that this adds onto the given style, so it must have been initialized
+ * already.
  */
 int
 style_parse(struct style *sy, const struct grid_cell *base, const char *in)
@@ -74,7 +76,11 @@ style_parse(struct style *sy, const struct grid_cell *base, const char *in)
 			sy->gc.bg = base->bg;
 			sy->gc.attr = base->attr;
 			sy->gc.flags = base->flags;
-		} else if (strcasecmp(tmp, "nolist") == 0)
+		} else if (strcasecmp(tmp, "push-default") == 0)
+			sy->default_type = STYLE_DEFAULT_PUSH;
+		else if (strcasecmp(tmp, "pop-default") == 0)
+			sy->default_type = STYLE_DEFAULT_POP;
+		else if (strcasecmp(tmp, "nolist") == 0)
 			sy->list = STYLE_LIST_OFF;
 		else if (strncasecmp(tmp, "list=", 5) == 0) {
 			if (strcasecmp(tmp + 5, "on") == 0)
@@ -218,6 +224,14 @@ style_tostring(struct style *sy)
 		    tmp);
 		comma = ",";
 	}
+	if (sy->default_type != STYLE_DEFAULT_BASE) {
+		if (sy->default_type == STYLE_DEFAULT_PUSH)
+			tmp = "push-default";
+		else if (sy->default_type == STYLE_DEFAULT_POP)
+			tmp = "pop-default";
+		off += xsnprintf(s + off, sizeof s - off, "%s%s", comma, tmp);
+		comma = ",";
+	}
 	if (sy->fill != 8) {
 		off += xsnprintf(s + off, sizeof s - off, "%sfill=%s", comma,
 		    colour_tostring(sy->fill));
@@ -257,21 +271,6 @@ style_apply(struct grid_cell *gc, struct options *oo, const char *name)
 	gc->attr |= sy->gc.attr;
 }
 
-/* Apply a style, updating if default. */
-void
-style_apply_update(struct grid_cell *gc, struct options *oo, const char *name)
-{
-	struct style	*sy;
-
-	sy = options_get_style(oo, name);
-	if (sy->gc.fg != 8)
-		gc->fg = sy->gc.fg;
-	if (sy->gc.bg != 8)
-		gc->bg = sy->gc.bg;
-	if (sy->gc.attr != 0)
-		gc->attr |= sy->gc.attr;
-}
-
 /* Initialize style from cell. */
 void
 style_set(struct style *sy, const struct grid_cell *gc)

tmux.1

@@ -4333,7 +4333,9 @@ and
 .Pp
 A style may be the single term
 .Ql default
-to specify the default style (which may inherit from another option) or a space
+to specify the default style (which may come from an option, for example
+.Ic status-style
+in the status line) or a space
 or comma separated list of the following:
 .Bl -tag -width Ds
 .It Ic fg=colour
@@ -4412,6 +4414,20 @@ and
 .Ic list=right-marker
 mark the text to be used to mark that text has been trimmed from the left or
 right of the list if there is not enough space.
+.It Xo Ic push-default ,
+.Ic pop-default
+.Xc
+Store the current colours and attributes as the default or reset to the previous
+default.
+A
+.Ic push-default
+affects any subsequent use of the
+.Ic default
+term until a
+.Ic pop-default .
+Only one default may be pushed (each
+.Ic push-default
+replaces the previous saved default).
 .It Xo Ic range=left ,
 .Ic range=right ,
 .Ic range=window|X ,

tmux.h

@@ -680,6 +680,13 @@ struct style_range {
 };
 TAILQ_HEAD(style_ranges, style_range);
 
+/* Style default. */
+enum style_default_type {
+	STYLE_DEFAULT_BASE,
+	STYLE_DEFAULT_PUSH,
+	STYLE_DEFAULT_POP
+};
+
 /* Style option. */
 struct style {
 	struct grid_cell	gc;
@@ -690,6 +697,8 @@ struct style {
 
 	enum style_range_type	range_type;
 	u_int			range_argument;
+
+	enum style_default_type	default_type;
 };
 
 /* Virtual screen. */
@@ -2648,8 +2657,6 @@ int		 style_parse(struct style *,const struct grid_cell *,
 const char	*style_tostring(struct style *);
 void		 style_apply(struct grid_cell *, struct options *,
 		     const char *);
-void		 style_apply_update(struct grid_cell *, struct options *,
-		     const char *);
 int		 style_equal(struct style *, struct style *);
 void		 style_set(struct style *, const struct grid_cell *);
 void		 style_copy(struct style *, struct style *);