From 0687d7ff7be3fea2f1ebd9dd78eb89eacc44d209 Mon Sep 17 00:00:00 2001
From: Martin Lund <martin.lund@keep-it-simple.com>
Date: Tue, 17 May 2016 11:53:57 +0200
Subject: [PATCH] Further simplification of key handling

Changed so that the "ctrl-t ctrl-t" sequence is now simply "ctrl-t t" to
send the ctrl-t key code. This is inspired by screen which does similar
to send its command key code (ctrl-a a).

This change also allows to easier add new key commands if needed.

Updated man page accordingly.
---
 man/tio.1               |  9 +++++--
 src/include/tio/print.h |  4 ++++
 src/include/tio/tty.h   |  1 +
 src/tty.c               | 52 +++++++++++++++++++++++++++++------------
 4 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/man/tio.1 b/man/tio.1
index c744961..5e4e1d7 100644
--- a/man/tio.1
+++ b/man/tio.1
@@ -58,8 +58,13 @@ Display program version.
 Display help.
 
 .SH "KEYS"
-.TP
-In session, press ctrl-t + q to quit.
+.PP
+.TP 16n
+In session, the following key sequences are intercepted as tio commands:
+.IP "\fBctrl-t q"
+Quit
+.IP "\fBctrl-t t"
+Send ctrl-t key code
 
 .SH "EXAMPLES"
 .TP
diff --git a/src/include/tio/print.h b/src/include/tio/print.h
index 7eb06cb..7254174 100644
--- a/src/include/tio/print.h
+++ b/src/include/tio/print.h
@@ -36,6 +36,10 @@
    fprintf (stdout, "\r" ANSI_COLOR_YELLOW format ANSI_COLOR_RESET "\r\n", ## args); \
    fflush(stdout);
 
+#define warning_printf(format, args...) \
+   fprintf (stdout, "\rWarning: " format "\r\n", ## args); \
+   fflush(stdout);
+
 #ifdef DEBUG
 #define debug_printf(format, args...) \
    fprintf (stdout, "[debug] " format, ## args)
diff --git a/src/include/tio/tty.h b/src/include/tio/tty.h
index 3ada24f..9324dfd 100644
--- a/src/include/tio/tty.h
+++ b/src/include/tio/tty.h
@@ -24,6 +24,7 @@
 
 #define KEY_CTRL_T 0x14
 #define KEY_Q 0x71
+#define KEY_T 0x74
 
 void configure_stdout(void);
 void restore_stdout(void);
diff --git a/src/tty.c b/src/tty.c
index 9e4d99d..845334f 100644
--- a/src/tty.c
+++ b/src/tty.c
@@ -166,8 +166,9 @@ int connect_tty(void)
 {
     fd_set rdfs;           /* Read file descriptor set */
     int    maxfd;          /* Maximum file descriptor used */
+    char   input_char, output_char;
+    static char previous_char = 0;
     static bool first = true;
-    static char input_char, previous_char = 0;
     int    status;
 
     /* Open tty device */
@@ -261,6 +262,8 @@ int connect_tty(void)
             }
             if (FD_ISSET(STDIN_FILENO, &rdfs))
             {
+                char forward = true;
+
                 /* Input from stdin ready */
                 status = read(STDIN_FILENO, &input_char, 1);
                 if (status <= 0)
@@ -269,25 +272,44 @@ int connect_tty(void)
                     goto error_read;
                 }
 
-                /* Exit upon ctrl-t + q sequence */
-                if ((input_char == KEY_Q) && (previous_char == KEY_CTRL_T))
-                    exit(EXIT_SUCCESS);
+                /* Forward input to output except ctrl-t key */
+                output_char = input_char;
+                if (input_char == KEY_CTRL_T)
+                    forward = false;
 
-                /* Ignore ctrl-t except when repeated */
-                if ((input_char != KEY_CTRL_T) ||
-                        ((input_char == KEY_CTRL_T) && (previous_char == KEY_CTRL_T)))
+                /* Handle escape key commands */
+                if (previous_char == KEY_CTRL_T)
                 {
-                    /* Forward input to tty device */
-                    status = write(fd, &input_char, 1);
-                    if (status < 0)
-                        printf("Warning: Could not write to tty device\r\n");
+                    switch (input_char)
+                    {
+                        case KEY_Q:
+                            /* Exit upon ctrl-t q sequence */
+                            exit(EXIT_SUCCESS);
+                        case KEY_T:
+                            /* Send ctrl-t key code upon ctrl-t t sequence */
+                            output_char = KEY_CTRL_T;
+                            break;
+                        default:
+                            /* Ignore unknown ctrl-t escaped keys */
+                            forward = false;
+                            break;
+                    }
                 }
 
-                previous_char = input_char;
+                if (forward)
+                {
+                    /* Send output to tty device */
+                    status = write(fd, &output_char, 1);
+                    if (status < 0)
+                        warning_printf("Could not write to tty device");
 
-                /* Write to log */
-                if (option.log)
-                    log_write(input_char);
+                    /* Write to log */
+                    if (option.log)
+                        log_write(output_char);
+                }
+
+                /* Save previous key */
+                previous_char = input_char;
 
                 /* Insert output delay */
                 if (option.output_delay)