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

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@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!