shell: add option to toggle logs output

When logging through shell is enabled, it is inconvenient to use
the shell when there are logs coming in. Having a mechanism for
easy disabling/re-enabling the shell logs is a nice quality of life
feature.

To toggle the logs, `CTRL+T` combination can be used. This is
available only when meta key feature is enabled.

Signed-off-by: Heghedus Razvan <[email protected]>

Author: heghe

doc/services/shell/index.rst

@@ -664,6 +664,8 @@ The shell module supports the following meta keys:
      - Moves in history to next entry.
    * - :kbd:`Ctrl+p`
      - Moves in history to previous entry.
+   * - :kbd:`Ctrl+t`
+     - Toggles logs output on the shell when :kconfig:option:`CONFIG_SHELL_LOG_BACKEND` is set.
    * - :kbd:`Ctrl+u`
      - Clears the currently typed command.
    * - :kbd:`Ctrl+w`

subsys/shell/shell.c

@@ -812,6 +812,21 @@ static int execute(const struct shell *sh)
 			&argv[cmd_with_handler_lvl], &help_entry);
 }
 
+static void toggle_logs_output(const struct shell *sh)
+{
+	const struct shell_log_backend *backend = sh->log_backend;
+
+	if (!IS_ENABLED(CONFIG_SHELL_LOG_BACKEND)) {
+		return;
+	}
+
+	if (backend->control_block->state == SHELL_LOG_BACKEND_ENABLED) {
+		z_shell_log_backend_disable(backend);
+	} else if (backend->control_block->state == SHELL_LOG_BACKEND_DISABLED) {
+		z_shell_log_backend_enable(backend, (void *)sh, sh->ctx->log_level);
+	}
+}
+
 static void tab_handle(const struct shell *sh)
 {
 	const char *__argv[CONFIG_SHELL_ARGC_MAX + 1];
@@ -926,6 +941,10 @@ static void ctrl_metakeys_handle(const struct shell *sh, char data)
 		history_handle(sh, true);
 		break;
 
+	case SHELL_VT100_ASCII_CTRL_T: /* CTRL + T */
+		toggle_logs_output(sh);
+		break;
+
 	case SHELL_VT100_ASCII_CTRL_U: /* CTRL + U */
 		z_shell_op_cursor_home_move(sh);
 		cmd_buffer_clear(sh);
@@ -1840,7 +1859,7 @@ static int cmd_help(const struct shell *sh, size_t argc, char **argv)
 #if defined(CONFIG_SHELL_METAKEYS)
 	shell_print(sh,
 		"\nShell supports following meta-keys:\n"
-		"  Ctrl + (a key from: abcdefklnpuw)\n"
+		"  Ctrl + (a key from: abcdefklnptuw)\n"
 		"  Alt  + (a key from: bf)\n"
 		"Please refer to shell documentation for more details.");
 #endif

subsys/shell/shell_vt100.h

@@ -20,6 +20,7 @@
 #define SHELL_VT100_ASCII_CTRL_L	(0x0C)
 #define SHELL_VT100_ASCII_CTRL_N	(0x0E)
 #define SHELL_VT100_ASCII_CTRL_P	(0x10)
+#define SHELL_VT100_ASCII_CTRL_T	(0x14)
 #define SHELL_VT100_ASCII_CTRL_U	(0x15)
 #define SHELL_VT100_ASCII_CTRL_W	(0x17)
 #define SHELL_VT100_ASCII_ALT_B		(0x62)