Allow experimental libteken features to be tested without changing code.

The teken library already supports UTF-8 handling and xterm emulation,
but we have reasons to disable this right now. Because we should make it
easy and interesting for people to experiment with these features, allow
them to be set in kernel configuration files.

Before this commit we had a flag called `TEKEN_CONS25' to enable
cons25-style emulation. I'm calling it the opposite now, `TEKEN_XTERM',
because we want to enable it in kernel configuration files explicitly.

Requested by:	kib

sys/conf/NOTES

@@ -1370,6 +1370,10 @@ options 	SC_NO_SUSPEND_VTYSWITCH
 #	0x80	Put the video card in the VESA 800x600 dots, 16 color mode
 #	0x100	Probe for a keyboard device periodically if one is not present
 
+# Enable experimental features of the syscons terminal emulator (teken).
+options		TEKEN_UTF8		# UTF-8 output handling
+options		TEKEN_XTERM		# xterm-style terminal emulation
+
 #
 # Optional devices:
 #

sys/conf/options

@@ -726,6 +726,10 @@ SC_PIXEL_MODE		opt_syscons.h
 SC_RENDER_DEBUG		opt_syscons.h
 SC_TWOBUTTON_MOUSE	opt_syscons.h
 
+# teken terminal emulator options
+TEKEN_UTF8		opt_teken.h
+TEKEN_XTERM		opt_teken.h
+
 # options for printf
 PRINTF_BUFR_SIZE	opt_printf.h
 

sys/dev/syscons/teken/teken.c

@@ -56,11 +56,11 @@ static inline int
 teken_wcwidth(teken_char_t c __unused)
 {
 
-#ifdef TEKEN_CONS25
-	return (1);
-#else /* !TEKEN_CONS25 */
+#ifdef TEKEN_XTERM
 	return (c <= 0x1B) ? -1 : 1;
-#endif /* TEKEN_CONS25 */
+#else /* !TEKEN_XTERM */
+	return (1);
+#endif /* TEKEN_XTERM */
 }
 #endif /* TEKEN_UTF8 */
 
@@ -72,11 +72,11 @@ teken_wcwidth(teken_char_t c __unused)
 #define	TS_INSERT	0x02	/* Insert mode. */
 #define	TS_AUTOWRAP	0x04	/* Autowrap. */
 #define	TS_ORIGIN	0x08	/* Origin mode. */
-#ifdef TEKEN_CONS25
-#define	TS_WRAPPED	0x00	/* Simple line wrapping. */
-#else /* !TEKEN_CONS25 */
+#ifdef TEKEN_XTERM
 #define	TS_WRAPPED	0x10	/* Next character should be printed on col 0. */
-#endif /* TEKEN_CONS25 */
+#else /* !TEKEN_XTERM */
+#define	TS_WRAPPED	0x00	/* Simple line wrapping. */
+#endif /* TEKEN_XTERM */
 
 /* Character that blanks a cell. */
 #define	BLANK	' '

sys/dev/syscons/teken/teken.h

@@ -33,18 +33,16 @@
  * libteken: terminal emulation library.
  *
  * This library converts an UTF-8 stream of bytes to terminal drawing
- * commands. It implements commands similar to xterm-color.
+ * commands.
+ *
+ * Configuration switches:
+ * - TEKEN_UTF8: Enable/disable UTF-8 handling.
+ * - TEKEN_XTERM: Enable xterm-style emulation, instead of cons25.
  */
 
-#if 0
-/*
- * XXX: Disable UTF-8 support for now. It requires UTF-8 keyboard input
- * and rendering, which we do not yet support.
- */
-#define	TEKEN_UTF8
-#endif
-/* Emulate cons25-like behaviour. */
-#define	TEKEN_CONS25
+#if defined(__FreeBSD__) && defined(_KERNEL)
+#include "opt_teken.h"
+#endif /* __FreeBSD__ && _KERNEL */
 
 #ifdef TEKEN_UTF8
 typedef uint32_t teken_char_t;

sys/dev/syscons/teken/teken_demo.c

@@ -279,11 +279,11 @@ main(int argc __unused, char *argv[] __unused)
 		perror("forkpty");
 		exit(1);
 	case 0:
-#ifdef TEKEN_CONS25
-		setenv("TERM", "cons25", 1);
-#else /* !TEKEN_CONS25 */
+#ifdef TEKEN_XTERM
 		setenv("TERM", "xterm", 1);
-#endif /* TEKEN_CONS25 */
+#else /* !TEKEN_XTERM */
+		setenv("TERM", "cons25", 1);
+#endif /* TEKEN_XTERM */
 #ifdef TEKEN_UTF8
 		setenv("LC_CTYPE", "UTF-8", 0);
 #endif /* TEKEN_UTF8 */

sys/dev/syscons/teken/teken_subr.h

@@ -198,7 +198,13 @@ static void
 teken_subr_backspace(teken_t *t)
 {
 
-#ifdef TEKEN_CONS25
+#ifdef TEKEN_XTERM
+	if (t->t_cursor.tp_col == 0)
+		return;
+
+	t->t_cursor.tp_col--;
+	t->t_stateflags &= ~TS_WRAPPED;
+#else /* !TEKEN_XTERM */
 	if (t->t_cursor.tp_col == 0) {
 		if (t->t_cursor.tp_row == t->t_originreg.ts_begin)
 			return;
@@ -207,13 +213,7 @@ teken_subr_backspace(teken_t *t)
 	} else {
 		t->t_cursor.tp_col--;
 	}
-#else /* !TEKEN_CONS25 */
-	if (t->t_cursor.tp_col == 0)
-		return;
-
-	t->t_cursor.tp_col--;
-	t->t_stateflags &= ~TS_WRAPPED;
-#endif /* TEKEN_CONS25 */
+#endif /* TEKEN_XTERM */
 
 	teken_funcs_cursor(t);
 }
@@ -542,10 +542,7 @@ teken_subr_horizontal_position_absolute(teken_t *t, unsigned int col)
 static void
 teken_subr_horizontal_tab(teken_t *t)
 {
-#ifdef TEKEN_CONS25
-
-	teken_subr_cursor_forward_tabulation(t, 1);
-#else /* !TEKEN_CONS25 */
+#ifdef TEKEN_XTERM
 	teken_rect_t tr;
 
 	tr.tr_begin = t->t_cursor;
@@ -556,7 +553,10 @@ teken_subr_horizontal_tab(teken_t *t)
 	/* Blank region that we skipped. */
 	if (tr.tr_end.tp_col > tr.tr_begin.tp_col)
 		teken_funcs_fill(t, &tr, BLANK, &t->t_curattr);
-#endif /* TEKEN_CONS25 */
+#else /* !TEKEN_XTERM */
+
+	teken_subr_cursor_forward_tabulation(t, 1);
+#endif /* TEKEN_XTERM */
 }
 
 static void
@@ -664,7 +664,10 @@ teken_subr_newline(teken_t *t)
 static void
 teken_subr_newpage(teken_t *t)
 {
-#ifdef TEKEN_CONS25
+#ifdef TEKEN_XTERM
+
+	teken_subr_newline(t);
+#else /* !TEKEN_XTERM */
 	teken_rect_t tr;
 
 	tr.tr_begin.tp_row = tr.tr_begin.tp_col = 0;
@@ -673,10 +676,7 @@ teken_subr_newpage(teken_t *t)
 
 	t->t_cursor.tp_row = t->t_cursor.tp_col = 0;
 	teken_funcs_cursor(t);
-#else /* !TEKEN_CONS25 */
-
-	teken_subr_newline(t);
-#endif /* TEKEN_CONS25 */
+#endif /* TEKEN_XTERM */
 }
 
 static void
@@ -746,22 +746,7 @@ teken_subr_regular_character(teken_t *t, teken_char_t c)
 	if (width <= 0)
 		return;
 
-#ifdef TEKEN_CONS25
-	teken_subr_do_putchar(t, &t->t_cursor, c, width);
-	t->t_cursor.tp_col += width;
-
-	if (t->t_cursor.tp_col >= t->t_winsize.tp_col) {
-		if (t->t_cursor.tp_row == t->t_scrollreg.ts_end - 1) {
-			/* Perform scrolling. */
-			teken_subr_do_scroll(t, 1);
-		} else {
-			/* No scrolling needed. */
-			if (t->t_cursor.tp_row < t->t_winsize.tp_row - 1)
-				t->t_cursor.tp_row++;
-		}
-		t->t_cursor.tp_col = 0;
-	}
-#else /* !TEKEN_CONS25 */
+#ifdef TEKEN_XTERM
 	if (t->t_cursor.tp_col == t->t_winsize.tp_col - 1 &&
 	    (t->t_stateflags & (TS_WRAPPED|TS_AUTOWRAP)) ==
 	    (TS_WRAPPED|TS_AUTOWRAP)) {
@@ -806,7 +791,22 @@ teken_subr_regular_character(teken_t *t, teken_char_t c)
 			t->t_stateflags &= ~TS_WRAPPED;
 		}
 	}
-#endif /* TEKEN_CONS25 */
+#else /* !TEKEN_XTERM */
+	teken_subr_do_putchar(t, &t->t_cursor, c, width);
+	t->t_cursor.tp_col += width;
+
+	if (t->t_cursor.tp_col >= t->t_winsize.tp_col) {
+		if (t->t_cursor.tp_row == t->t_scrollreg.ts_end - 1) {
+			/* Perform scrolling. */
+			teken_subr_do_scroll(t, 1);
+		} else {
+			/* No scrolling needed. */
+			if (t->t_cursor.tp_row < t->t_winsize.tp_row - 1)
+				t->t_cursor.tp_row++;
+		}
+		t->t_cursor.tp_col = 0;
+	}
+#endif /* TEKEN_XTERM */
 
 	teken_funcs_cursor(t);
 }