[U-Boot] [PATCH v2] common: cli_readline: Improve command line editing

[Tom Rini]

On Sun, Jul 31, 2016 at 10:58:15PM +0100, James Byrne wrote:

> This improves the cread_line() function so that it will correctly
> process the 'Home', 'End', 'Delete' and arrow key escape sequences
> produced by various terminal emulators. This makes command line editing
> a more pleasant experience.
> 
> The previous code only supported the cursor keys and the 'Home' key, and
> only for certain terminal emulator configurations. This adds support for
> the 'End and 'Delete' keys, and recognises a wider range of escape
> sequences. For example, the left arrow key can be 'ESC O D' instead of
> 'ESC [ D', and the 'Home' key can be 'ESC [ H', 'ESC O H', 'ESC 1 ~' or
> 'ESC 7 ~', depending on what terminal emulator you use and how it is
> configured.
> 
> Signed-off-by: James Byrne <james.byrne at origamienergy.com>
> ---
> Changes for v2
>    - Explicitly initialize variable to avoid spurious compiler warning.

Thanks.  But now:

> 
>  common/cli_readline.c | 108 ++++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 78 insertions(+), 30 deletions(-)
> 
> diff --git a/common/cli_readline.c b/common/cli_readline.c
> index c1476e4..6690c13 100644
> --- a/common/cli_readline.c
> +++ b/common/cli_readline.c
> @@ -283,46 +283,94 @@ static int cread_line(const char *const prompt, char *buf, unsigned int *len,
>  		 * handle standard linux xterm esc sequences for arrow key, etc.
>  		 */
>  		if (esc_len != 0) {
> +			enum { ESC_REJECT, ESC_SAVE, ESC_CONVERTED } act = ESC_REJECT;
> +
>  			if (esc_len == 1) {
> -				if (ichar == '[') {
> -					esc_save[esc_len] = ichar;
> -					esc_len = 2;
> +				if (ichar == '[' || ichar == 'O')
> +					act = ESC_SAVE;
> +				else
> +					act = ESC_REJECT;

Since act is ESC_REJECT to start with, we can kill the else.

> +			} else if (esc_len == 2) {
> +				switch (ichar) {
> +				case 'D':	/* <- key */
> +					ichar = CTL_CH('b');
> +					act = ESC_CONVERTED;
> +					break;	/* pass off to ^B handler */
> +				case 'C':	/* -> key */
> +					ichar = CTL_CH('f');
> +					act = ESC_CONVERTED;
> +					break;	/* pass off to ^F handler */
> +				case 'H':	/* Home key */
> +					ichar = CTL_CH('a');
> +					act = ESC_CONVERTED;
> +					break;	/* pass off to ^A handler */
> +				case 'F':	/* End key */
> +					ichar = CTL_CH('e');
> +					act = ESC_CONVERTED;
> +					break;	/* pass off to ^E handler */
> +				case 'A':	/* up arrow */
> +					ichar = CTL_CH('p');
> +					act = ESC_CONVERTED;
> +					break;	/* pass off to ^P handler */
> +				case 'B':	/* down arrow */
> +					ichar = CTL_CH('n');
> +					act = ESC_CONVERTED;
> +					break;	/* pass off to ^N handler */
> +				case '1':
> +				case '3':
> +				case '4':
> +				case '7':
> +				case '8':
> +					if (esc_save[1] == '[') {
> +						/* see if next character is ~ */
> +						act = ESC_SAVE;
> +					} else {
> +						act = ESC_REJECT;
> +					}

And here too.

> +					break;
> +				default:
> +					act = ESC_REJECT;
> +					break;

And then we can drop the default case too.

> +				}
> +			} else if (esc_len == 3) {
> +				if (ichar == '~') {
> +					switch (esc_save[2]) {
> +					case '3':	/* Delete key */
> +						ichar = CTL_CH('d');
> +						act = ESC_CONVERTED;
> +						break;	/* pass to ^D handler */
> +					case '1':	/* Home key */
> +					case '7':
> +						ichar = CTL_CH('a');
> +						act = ESC_CONVERTED;
> +						break;	/* pass to ^A handler */
> +					case '4':	/* End key */
> +					case '8':
> +						ichar = CTL_CH('e');
> +						act = ESC_CONVERTED;
> +						break;	/* pass to ^E handler */
> +					default:
> +						act = ESC_REJECT;
> +						break;

Same.

> +					}
>  				} else {
> -					cread_add_str(esc_save, esc_len,
> -						      insert, &num, &eol_num,
> -						      buf, *len);
> -					esc_len = 0;
> +					act = ESC_REJECT;
>  				}

And this is also redundant.

Thanks!

-- 
Tom
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