nano

commit be203832408da8076da555cab8e9f4690a6da2ff
parent cf769bbd2f4c5a76e62bcab4be80d45ac559cb40
Author: Benno Schulenberg <bensberg@telfort.nl>
Date:   Mon, 10 Aug 2020 09:24:22 +0200

verbatim: report and ignore an invalid keystroke for Unicode input

When Unicode Input has started (by typing 0 or 1 at the Verbatim Input
"prompt"), and something is typed that is not a hexadecimal digit, then
don't try to enter this character into the buffer but simply report it
as invalid and ignore it.  Because most likely the user mistyped and
actually meant to enter a valid hex digit.

This fixes https://savannah.gnu.org/bugs/?58927.

The bug was old -- it existed since at least version 2.0.6.

Diffstat:
M
src/winio.c
 | 
11
+++++++++--

1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/src/winio.c b/src/winio.c
@@ -1278,6 +1278,8 @@ int get_kbinput(WINDOW *win, bool showcursor)
 }
 
 #ifdef ENABLE_UTF8
+#define INVALID_DIGIT  -77
+
 /* If the given symbol is a valid hexadecimal digit, multiply it by factor
  * and add the result to the given unicode, and return PROCEED to signify
  * okay.  When not a hexadecimal digit, return the symbol itself. */
@@ -1288,7 +1290,7 @@ long add_unicode_digit(int symbol, long factor, long *unicode)
 	else if ('a' <= tolower(symbol) && tolower(symbol) <= 'f')
 		*unicode += (tolower(symbol) - 'a' + 10) * factor;
 	else
-		return (long)symbol;
+		return INVALID_DIGIT;
 
 	return PROCEED;
 }
@@ -1312,7 +1314,7 @@ long assemble_unicode(int symbol)
 			if (symbol == '0' || unicode == 0)
 				retval = add_unicode_digit(symbol, 0x10000, &unicode);
 			else
-				retval = symbol;
+				retval = INVALID_DIGIT;
 			break;
 		case 3:
 			/* Later digits may be any hexadecimal value. */
@@ -1395,6 +1397,11 @@ int *parse_verbatim_kbinput(WINDOW *win, size_t *count)
 			unicode = assemble_unicode(keycode);
 		}
 
+		/* For an invalid digit, discard its possible continuation bytes. */
+		if (unicode == INVALID_DIGIT)
+			while (key_buffer_len > 0 && 0x7F < *key_buffer && *key_buffer < 0xC0)
+				get_input(NULL);
+
 		/* Convert the Unicode value to a multibyte sequence. */
 		multibyte = make_mbchar(unicode, (int *)count);