Add support for Kitty Keyboard Protocol

Signed-off-by: Jakub Horký <jakub.github@horky.net>

Author: horkykuba

doc/man/mc.1.in

@@ -4190,6 +4190,13 @@ For example:
 .nf
 autodetect_codeset=russian
 .fi
+.TP
+.I kitty_keyboard_protocol
+By default, Midnight Commander sends an escape sequence that enables the Kitty
+Keyboard Protocol, which allows precise keyboard handling (including key
+combinations such as C-Enter or C-Alt-Enter) when connected from terminals that
+support this protocol. If set to false, Midnight Commander will not attempt to
+enable this protocol.
 .\"NODE "Parameters for external editor or viewer"
 .SH "Parameters for external editor or viewer"
 Midnight Commander provides a way for specify an options for external editors

lib/global.c

@@ -103,7 +103,8 @@ mc_global_t mc_global =
         .disable_colors = FALSE,
         .ugly_line_drawing = FALSE,
         .old_mouse = FALSE,
-        .alternate_plus_minus = FALSE
+        .alternate_plus_minus = FALSE,
+        .kitty_keyboard_protocol = TRUE
     },
 
     .vfs =

lib/global.h

@@ -206,6 +206,10 @@ typedef struct
         /* If true, use + and \ keys normally and select/unselect do if M-+ / M-\.
            and M-- and keypad + / - */
         gboolean alternate_plus_minus;
+
+        // If true, send Kitty Keyboard Protocol initialization string to the terminal
+        // Defaults to true, because terminals that don't support it simply do nothing
+        gboolean kitty_keyboard_protocol;
     } tty;
 
     struct

lib/tty/key.c

@@ -263,6 +263,7 @@ tty_init (gboolean mouse_enable, gboolean is_xterm)
     noecho ();
     keypad (stdscr, TRUE);
     nodelay (stdscr, FALSE);
+    tty_kitty (TRUE);
 
     tty_setup_sigwinch (sigwinch_handler);
 }
@@ -273,6 +274,7 @@ void
 tty_shutdown (void)
 {
     tty_destroy_winch_pipe ();
+    tty_kitty (FALSE);
     tty_reset_shell_mode ();
     tty_noraw_mode ();
     tty_keypad (FALSE);

lib/tty/tty-ncurses.c

@@ -334,6 +334,7 @@ tty_init (gboolean mouse_enable, gboolean is_xterm)
     tty_enter_ca_mode ();
     tty_keypad (TRUE);
     tty_nodelay (FALSE);
+    tty_kitty (TRUE);
 
     tty_setup_sigwinch (sigwinch_handler);
 }
@@ -346,6 +347,7 @@ tty_shutdown (void)
     char *op_cap;
 
     tty_destroy_winch_pipe ();
+    tty_kitty (FALSE);
     tty_reset_shell_mode ();
     tty_noraw_mode ();
     tty_keypad (FALSE);

lib/tty/tty-slang.c

@@ -426,3 +426,24 @@ tty_init_xterm_support (gboolean is_xterm)
 }
 
 /* --------------------------------------------------------------------------------------------- */
+
+/** Enable or disable Kitty Keyboard Protocol */
+void
+tty_kitty (gboolean set)
+{
+    if (!mc_global.tty.kitty_keyboard_protocol)
+        return;
+
+    if (set)
+    {
+        // 1 = Disambiguate escape codes
+        // 4 = Report alternate keys (required for detecting Ctrl+Alt+key)
+        // 8 = Report all keys as escape codes (required for distinguishing keypad keys [+-*])
+        SLtt_write_string ((char*) ESC_STR "[>13u");
+    }
+    else
+        SLtt_write_string ((char*) ESC_STR "[<u");
+}
+
+/* --------------------------------------------------------------------------------------------- */
+

lib/tty/tty.c

@@ -95,6 +95,7 @@ extern int tty_flush_input (void);
 extern void tty_keypad (gboolean set);
 extern void tty_nodelay (gboolean set);
 extern int tty_baudrate (void);
+extern void tty_kitty (gboolean set);
 
 /* {{{ Output }}} */
 

lib/tty/tty.h

@@ -87,6 +87,7 @@ edition_post_exec (void)
     tty_flush_input ();
 
     tty_keypad (TRUE);
+    tty_kitty (TRUE);
     tty_raw_mode ();
     channels_up ();
     enable_mouse ();
@@ -113,6 +114,7 @@ edition_pre_exec (void)
     disable_bracketed_paste ();
 
     tty_reset_shell_mode ();
+    tty_kitty (FALSE);
     tty_keypad (FALSE);
     tty_reset_screen ();
 
@@ -485,6 +487,7 @@ toggle_subshell (void)
     tty_reset_shell_mode ();
 #endif
     tty_noecho ();
+    tty_kitty (FALSE);
     tty_keypad (FALSE);
     tty_reset_screen ();
     tty_exit_ca_mode ();
@@ -521,6 +524,7 @@ toggle_subshell (void)
 
     tty_reset_prog_mode ();
     tty_keypad (TRUE);
+    tty_kitty (TRUE);
 
     /* Prevent screen flash when user did 'exit' or 'logout' within
        subshell */

src/execute.c

@@ -367,6 +367,7 @@ static const struct
 #ifdef ENABLE_EXT2FS_ATTR
     { "copymove_persistent_ext2_attr", &copymove_persistent_ext2_attr },
 #endif
+    { "kitty_keyboard_protocol", &mc_global.tty.kitty_keyboard_protocol },
     {
         NULL,
         NULL,