Try to guess if the window is UTF-8 by outputting a three-byte UTF-8 wide character and seeing how much the cursor moves. Currently tries to figure out if this works by some stupid checks on the terminal, these need to be rethought. Also might be better using a width 1 character rather than width 2.

1 files changed, 86 insertions, 3 deletions

diff --git a/tty.c b/tty.c
index 72224039..9920b4a1 100644
--- a/tty.c
+++ b/tty.c
@@ -1,4 +1,4 @@
-/* $Id: tty.c,v 1.98 2009-05-14 16:21:55 nicm Exp $ */
+/* $Id: tty.c,v 1.99 2009-05-19 16:08:35 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -136,6 +136,8 @@ tty_start_tty(struct tty *tty)
 	int		 what;
 #endif
 
+	tty_detect_utf8(tty);
+
 	if (tcgetattr(tty->fd, &tty->tio) != 0)
 		fatal("tcgetattr failed");
 	memcpy(&tio, &tty->tio, sizeof tio);
@@ -197,16 +199,97 @@ tty_stop_tty(struct tty *tty)
 	tty_raw(tty, tty_term_string2(tty->term, TTYC_CSR, 0, ws.ws_row - 1));
 	tty_raw(tty, tty_term_string(tty->term, TTYC_RMACS));
 	tty_raw(tty, tty_term_string(tty->term, TTYC_SGR0));
-	tty_raw(tty, tty_term_string(tty->term, TTYC_CLEAR));
 	tty_raw(tty, tty_term_string(tty->term, TTYC_RMKX));
 	tty_raw(tty, tty_term_string(tty->term, TTYC_RMCUP));
-
+	tty_raw(tty, tty_term_string(tty->term, TTYC_CLEAR));
+	
 	tty_raw(tty, tty_term_string(tty->term, TTYC_CNORM));
 	if (tty_term_has(tty->term, TTYC_KMOUS))
 		tty_raw(tty, "\033[?1000l");
 }
 
 void
+tty_detect_utf8(struct tty *tty)
+{
+	struct pollfd	pfd;
+	char	      	buf[7];
+	size_t		len;
+	ssize_t		n;
+	int		nfds;
+	struct termios	tio, old_tio;
+#ifdef TIOCFLUSH
+	int		 what;
+#endif
+
+	if (tty->flags & TTY_UTF8)
+		return;
+
+	/*
+	 * If the terminal looks reasonably likely to support this, try to
+	 * write a three-byte UTF-8 wide character to the terminal, then read
+	 * the cursor position.
+	 *
+	 * XXX This entire function is a hack.
+	 */
+
+	/* Check if the terminal looks sort of vt100. */
+	if (strstr(tty_term_string(tty->term, TTYC_CLEAR), "[2J") == NULL ||
+	    strstr(tty_term_string(tty->term, TTYC_CUP), "H") == NULL)
+		return;
+
+	if (tcgetattr(tty->fd, &old_tio) != 0)
+		fatal("tcgetattr failed");
+	cfmakeraw(&tio);
+	if (tcsetattr(tty->fd, TCSANOW, &tio) != 0)
+		fatal("tcsetattr failed");
+
+#ifdef TIOCFLUSH
+	what = 0;
+	if (ioctl(tty->fd, TIOCFLUSH, &what) != 0)
+		fatal("ioctl(TIOCFLUSH)");
+#endif
+
+#define UTF8_TEST_DATA "\033[H\357\277\246\033[6n"
+	if (write(tty->fd, UTF8_TEST_DATA, (sizeof UTF8_TEST_DATA) - 1) == -1)
+		fatal("write failed");
+#undef UTF8_TEST_DATA
+
+	len = 0;
+	for (;;) {
+		pfd.fd = tty->fd;
+		pfd.events = POLLIN;
+
+		nfds = poll(&pfd, 1, 500);
+		if (nfds == -1) {
+			if (errno == EAGAIN || errno == EINTR)
+				continue;
+			fatal("poll failed");
+		}
+		if (nfds == 0)
+			break;
+#ifdef HAVE_POLL
+		if (pfd.revents & (POLLERR|POLLNVAL|POLLHUP))
+			break;
+#endif
+		if (!(pfd.revents & POLLIN))
+			continue;
+
+		if ((n = read(tty->fd, buf + len, 1)) != 1)
+			break;
+		buf[++len] = '\0';
+
+		if (len == (sizeof buf) - 1) {
+			if (strcmp(buf, "\033[1;3R") == 0)
+				tty->flags |= TTY_UTF8;
+			break;
+		}
+	}
+
+	if (tcsetattr(tty->fd, TCSANOW, &old_tio) != 0)
+		fatal("tcsetattr failed");
+}
+
+void
 tty_fill_acs(struct tty *tty)
 {
 	const char *ptr;