New session option, status-utf8, to control the interpretation of top-bit-set

characters in status-left and status-right (if on, they are treated as UTF-8;
otherwise passed through).

cmd-set-option.c

@@ -73,6 +73,7 @@ const struct set_option_entry set_option_table[NSETOPTION] = {
 	{ "status-left-length", SET_OPTION_NUMBER, 0, SHRT_MAX, NULL },
 	{ "status-right", SET_OPTION_STRING, 0, 0, NULL },
 	{ "status-right-length", SET_OPTION_NUMBER, 0, SHRT_MAX, NULL },
+	{ "status-utf8", SET_OPTION_FLAG, 0, 0, NULL },
 };
 
 int

screen-write.c

@@ -53,8 +53,8 @@ screen_write_putc(
 }
 
 /* Calculate string length. */
-size_t printflike1
-screen_write_strlen(const char *fmt, ...)
+size_t printflike2
+screen_write_strlen(int utf8flag, const char *fmt, ...)
 {
 	va_list	ap;
 	char   *msg;
@@ -67,7 +67,7 @@ screen_write_strlen(const char *fmt, ...)
 
 	ptr = msg;
 	while (*ptr != '\0') {
-		if (*ptr > 0x7f) {	/* Assume this is UTF-8. */
+		if (utf8flag && *ptr > 0x7f) {
 			memset(utf8buf, 0xff, sizeof utf8buf);
 
 			left = strlen(ptr);
@@ -94,7 +94,7 @@ screen_write_strlen(const char *fmt, ...)
 	return (size);
 }
 
-/* Write string. */
+/* Write simple string (no UTF-8 or maximum length). */
 void printflike3
 screen_write_puts(
     struct screen_write_ctx *ctx, struct grid_cell *gc, const char *fmt, ...)
@@ -102,25 +102,25 @@ screen_write_puts(
 	va_list	ap;
 
 	va_start(ap, fmt);
-	screen_write_vnputs(ctx, -1, gc, fmt, ap);
+	screen_write_vnputs(ctx, -1, gc, 0, fmt, ap);
 	va_end(ap);
 }
 
 /* Write string with length limit (-1 for unlimited). */
-void printflike4
+void printflike5
 screen_write_nputs(struct screen_write_ctx *ctx,
-    ssize_t maxlen, struct grid_cell *gc, const char *fmt, ...)
+    ssize_t maxlen, struct grid_cell *gc, int utf8flag, const char *fmt, ...)
 {
 	va_list	ap;
 
 	va_start(ap, fmt);
-	screen_write_vnputs(ctx, maxlen, gc, fmt, ap);
+	screen_write_vnputs(ctx, maxlen, gc, utf8flag, fmt, ap);
 	va_end(ap);
 }
 
 void
-screen_write_vnputs(struct screen_write_ctx *ctx,
-    ssize_t maxlen, struct grid_cell *gc, const char *fmt, va_list ap)
+screen_write_vnputs(struct screen_write_ctx *ctx, ssize_t maxlen,
+    struct grid_cell *gc, int utf8flag, const char *fmt, va_list ap)
 {
 	char   *msg;
 	u_char *ptr, utf8buf[4];
@@ -131,7 +131,7 @@ screen_write_vnputs(struct screen_write_ctx *ctx,
 
 	ptr = msg;
 	while (*ptr != '\0') {
-		if (*ptr > 0x7f) {	/* Assume this is UTF-8. */
+		if (utf8flag && *ptr > 0x7f) {
 			memset(utf8buf, 0xff, sizeof utf8buf);
 
 			left = strlen(ptr);

status.c

@@ -50,7 +50,7 @@ status_redraw(struct client *c)
 	size_t				llen, llen2, rlen, rlen2, offset;
 	size_t				xx, yy, sy, size, start, width;
 	struct grid_cell	        stdgc, gc;
-	int				larrow, rarrow;
+	int				larrow, rarrow, utf8flag;
 
 	left = right = NULL;
 
@@ -74,18 +74,21 @@ status_redraw(struct client *c)
 	if (yy == 0)
 		goto blank;
 
+	/* Caring about UTF-8 in status line? */
+	utf8flag = options_get_number(&s->options, "status-utf8");
+
 	/* Work out the left and right strings. */
 	left = status_replace(s, options_get_string(
 	    &s->options, "status-left"), c->status_timer.tv_sec);
 	llen = options_get_number(&s->options, "status-left-length");
-	llen2 = screen_write_strlen("%s", left);
+	llen2 = screen_write_strlen(utf8flag, "%s", left);
 	if (llen2 < llen)
 		llen = llen2;
 
 	right = status_replace(s, options_get_string(
 	    &s->options, "status-right"), c->status_timer.tv_sec);
 	rlen = options_get_number(&s->options, "status-right-length");
-	rlen2 = screen_write_strlen("%s", right);
+	rlen2 = screen_write_strlen(utf8flag, "%s", right);
 	if (rlen2 < rlen)
 		rlen = rlen2;
 	right[rlen] = '\0';
@@ -164,7 +167,8 @@ draw:
 	screen_write_start(&ctx, NULL, &c->status);
 	if (llen != 0) {
  		screen_write_cursormove(&ctx, 0, yy);
-		screen_write_nputs(&ctx, llen + 1, &stdgc, "%s ", left);
+		screen_write_nputs(
+		    &ctx, llen + 1, &stdgc, utf8flag, "%s ", left);
 		if (larrow)
 			screen_write_putc(&ctx, &stdgc, ' ');
 	} else {
@@ -221,7 +225,8 @@ draw:
 	/* Draw the last item. */
 	if (rlen != 0) {
 		screen_write_cursormove(&ctx, c->tty.sx - rlen - 1, yy);
-		screen_write_nputs(&ctx, rlen + 1, &stdgc, " %s", right);
+		screen_write_nputs(
+		    &ctx, rlen + 1, &stdgc, utf8flag, " %s", right);
 	}
 
 	/* Draw the arrows. */

tmux.1

@@ -1133,6 +1133,12 @@ may contain any of the following special character pairs:
 Where appropriate, these may be prefixed with a number to specify the maximum
 length, for example
 .Ql #24T .
+.Pp
+By default, UTF-8 in 
+.Ar string
+is not interpreted, to enable UTF-8, use the
+.Ic status-utf8
+option.
 .It Ic status-left-length Ar length
 Set the maximum
 .Ar length
@@ -1147,13 +1153,27 @@ As with
 .Ic status-left ,
 .Ar string
 will be passed to
-.Xr strftime 3
-and character pairs are replaced.
+.Xr strftime 3 ,
+character pairs are replaced, and UTF-8 is dependent on the
+.Ic status-utf8
+option.
 .It Ic status-right-length Ar length
 Set the maximum
 .Ar length
 of the right component of the status bar.
 The default is 40.
+.Pp
+.It Xo Ic status-utf8
+.Op Ic on | Ic off
+.Xc
+Instruct
+.Nm
+to treat top-bit-set characters in the
+.Ic status-left
+and
+.Ic status-right
+strings as UTF-8; notably, this is important for wide characters.
+This option defaults to off.
 .El
 .It Xo Ic set-password
 .Op Fl c

tmux.c

@@ -299,6 +299,7 @@ main(int argc, char **argv)
 	options_set_string(&global_options, "status-left", "[#S]");
 	options_set_string(
 	    &global_options, "status-right", "\"#24T\" %%H:%%M %%d-%%b-%%y");
+	options_set_number(&global_options, "status-utf8", 0);
 
 	options_init(&global_window_options, NULL);
 	options_set_number(&global_window_options, "aggressive-resize", 0);

tmux.h

@@ -69,6 +69,7 @@ extern const char    *__progname;
 #define printflike2 __attribute__ ((format (printf, 2, 3)))
 #define printflike3 __attribute__ ((format (printf, 3, 4)))
 #define printflike4 __attribute__ ((format (printf, 4, 5)))
+#define printflike5 __attribute__ ((format (printf, 5, 6)))
 
 /* Number of items in array. */
 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
@@ -928,7 +929,7 @@ struct set_option_entry {
 };
 extern const struct set_option_entry set_option_table[];
 extern const struct set_option_entry set_window_option_table[];
-#define NSETOPTION 24
+#define NSETOPTION 25
 #define NSETWINDOWOPTION 19
 
 /* tmux.c */
@@ -1347,13 +1348,13 @@ void	 grid_view_delete_cells(struct grid *, u_int, u_int, u_int);
 void	 screen_write_start(
     	     struct screen_write_ctx *, struct window_pane *, struct screen *);
 void	 screen_write_stop(struct screen_write_ctx *);
-size_t printflike1 screen_write_strlen(const char *, ...);
+size_t printflike2 screen_write_strlen(int, const char *, ...);
 void printflike3 screen_write_puts(struct screen_write_ctx *,
     	     struct grid_cell *, const char *, ...);
-void printflike4 screen_write_nputs(struct screen_write_ctx *,
-    	     ssize_t, struct grid_cell *, const char *, ...);
+void printflike5 screen_write_nputs(struct screen_write_ctx *,
+    ssize_t, struct grid_cell *, int, const char *, ...);
 void	 screen_write_vnputs(struct screen_write_ctx *,
-    	     ssize_t, struct grid_cell *, const char *, va_list);
+	     ssize_t, struct grid_cell *, int, const char *, va_list);
 void	 screen_write_putc(
     	     struct screen_write_ctx *, struct grid_cell *, u_char);
 void	 screen_write_copy(struct screen_write_ctx *,