0001-nanocat-process-escape-codes-in-raw-mode.patch

From 84824d1a83cd600b63cef42f63f79225500992ae Mon Sep 17 00:00:00 2001
From: Bruce Ashfield <bruce.ashfield@windriver.com>
Date: Thu, 19 Oct 2017 21:59:51 -0400
Subject: [PATCH] nanocat: process escape codes in raw mode

Escape codes (like arrow keys) were not being picked up by the
rawmode configured console as pending data. As such, we only sent
the first part of the code (i.e. ^), but not the second and
third parts (i.e. '[A') until more 'normal' data was input.

When that data triggered the read, the two remaining characters
were read and the full escape sequence processed by the other end
.. but with a lagg/offset that makes it unusable.

We can detect the escape code starting sequence ^ (aka 27) and then
prime our stdin check with two more characters. This lets us send
the entire code and we have full ansi escape sequences working

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
---
 tools/nanocat.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/nanocat.c b/tools/nanocat.c
index 747e06a50ea5..2891db05c7c7 100644
--- a/tools/nanocat.c
+++ b/tools/nanocat.c
@@ -732,12 +732,18 @@ void nn_resp_loop (nn_options_t *options, int sock)
     }
 }
 
+static int stdin_primed_data = 0;
 int stdin_data_avail()
 {
    struct timeval tv = { 0L, 0L };
    fd_set fds;
    FD_ZERO(&fds);
    FD_SET(0, &fds);
+
+   if ( stdin_primed_data > 0 ) {
+      stdin_primed_data--;
+      return 1;
+   }
    return select(1, &fds, NULL, NULL, &tv);
 }
 
@@ -864,12 +870,21 @@ void nn_stdin_loop (nn_options_t *options, int sock)
 		    while ( count < PIPE_BUF && rcount < PIPE_BUF ) {
 		       if (stdin_data_avail()) {
 			  c = getchar();
-
 			  if ( c == EOF || c == '\n' ) {
 			     /* kept around for cooked / unbuffered mode emulation */
 			     //printf( "The length of the line is %u\n", count );
 			     //count = 0;
 			  }
+			  if ( c == 27 ) {
+			     /* we are getting an escape code. The stdin check for data doesn't
+				return true for pending data .. but it is there. So we do two
+				more reads to get the rest. i.e., for arrow keys:
+				  '\033'
+				  '['
+				  'A', 'B', 'C' or 'D'
+			     */
+			     stdin_primed_data = 2;
+			  }
 			  if ( c == -1 ) {
 			     if ( rcount == 0 ) {
 				if ( exit_pending == 0 ) {
-- 
2.4.0.53.g8440f74