[PATCH v3] cli: Consume invalid escape sequences early

[Yurii Monakov]

Unexpected 'Esc' key presses are accumulated internally, even if it is
already clear that the current escape sequence is invalid. This results
in weird behaviour. For example, the next character after 'Esc' key
simply disappears from input and 'Unknown command' is printed
after 'Enter'.

This commit fixes some issues with extra 'Esc' keys entered by user:

1. Sequence <Esc><Esc><Enter> right after autoboot stop gives:
=>
nknown command 'ry 'help'
=>
2. Sequence <Esc><p><r><i><Enter> gives:
=> ri
Unknown command 'ri' - try 'help'
=>
3. Extra 'Esc' key presses break backspace functionality.

Signed-off-by: Yurii Monakov <monakov.y at gmail.com>
---
Changes for v2:
- add tests and reword commit message
Changes for v3:
- fix indentation

 common/cli_getch.c  |  2 ++
 test/common/cread.c | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/common/cli_getch.c b/common/cli_getch.c
index 61d4cb261b..0ee7908777 100644
--- a/common/cli_getch.c
+++ b/common/cli_getch.c
@@ -46,6 +46,8 @@ static int cli_ch_esc(struct cli_ch_state *cch, int
ichar,
 	case 1:
 		if (ichar == '[' || ichar == 'O')
 			act = ESC_SAVE;
+		else
+			act = ESC_CONVERTED;
 		break;
 	case 2:
 		switch (ichar) {
diff --git a/test/common/cread.c b/test/common/cread.c
index 2fdd29a265..4edc773960 100644
--- a/test/common/cread.c
+++ b/test/common/cread.c
@@ -43,6 +43,12 @@ static int cli_ch_test(struct unit_test_state *uts)
 	ut_asserteq('a', cli_ch_process(cch, 'a'));
 	ut_asserteq(0, cli_ch_process(cch, 0));
 
+	/* unexpected 'Esc' */
+	ut_asserteq('a', cli_ch_process(cch, 'a'));
+	ut_asserteq(0, cli_ch_process(cch, '\e'));
+	ut_asserteq('b', cli_ch_process(cch, 'b'));
+	ut_asserteq(0, cli_ch_process(cch, 0));
+
 	return 0;
 }
 COMMON_TEST(cli_ch_test, 0);
@@ -80,6 +86,12 @@ static int cread_test(struct unit_test_state *uts)
 	ut_asserteq(7, cli_readline_into_buffer("-> ", buf, 1));
 	ut_asserteq_str("abc\e[Xx", buf);
 
+	/* unexpected 'Esc' */
+	*buf = '\0';
+	ut_asserteq(7, console_in_puts("abc\eXx\n"));
+	ut_asserteq(5, cli_readline_into_buffer("-> ", buf, 1));
+	ut_asserteq_str("abcXx", buf);
+
 	/* check timeout, should be between 1000 and 1050ms */
 	start = get_timer(0);
 	*buf = '\0';
-- 
2.34.1