cli: Move readline character-processing to a state machine

The current cread_line() function is very long. It handles the escape
processing inline. The menu command does similar processing but at the
character level, so there is some duplication.

Split the character processing into a new function cli_ch_process() which
processes individual characters and returns the resulting input character,
taking account of escape sequences. It requires the caller to set up and
maintain its state.

Update cread_line() to use this new function.

The only intended functional change is that an invalid escape sequence
does not add invalid/control characters into the input buffer, but instead
discards these.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 22 insertions, 128 deletions

diff --git a/common/cli_readline.c b/common/cli_readline.c
index d6444f5fc1..709e9c3d38 100644
--- a/common/cli_readline.c
+++ b/common/cli_readline.c
@@ -62,7 +62,6 @@ static char *delete_char (char *buffer, char *p, int *colp, int *np, int plen)
 
 #define putnstr(str, n)	printf("%.*s", (int)n, str)
 
-#define CTL_CH(c)		((c) - 'a' + 1)
 #define CTL_BACKSPACE		('\b')
 #define DEL			((char)255)
 #define DEL7			((char)127)
@@ -252,156 +251,53 @@ static void cread_add_str(char *str, int strsize, int insert,
 static int cread_line(const char *const prompt, char *buf, unsigned int *len,
 		int timeout)
 {
+	struct cli_ch_state s_cch, *cch = &s_cch;
 	unsigned long num = 0;
 	unsigned long eol_num = 0;
 	unsigned long wlen;
 	char ichar;
 	int insert = 1;
-	int esc_len = 0;
-	char esc_save[8];
 	int init_len = strlen(buf);
 	int first = 1;
 
+	cli_ch_init(cch);
+
 	if (init_len)
 		cread_add_str(buf, init_len, 1, &num, &eol_num, buf, *len);
 
 	while (1) {
-		if (bootretry_tstc_timeout())
-			return -2;	/* timed out */
-		if (first && timeout) {
-			uint64_t etime = endtick(timeout);
-
-			while (!tstc()) {	/* while no incoming data */
-				if (get_ticks() >= etime)
-					return -2;	/* timed out */
-				schedule();
+		/* Check for saved characters */
+		ichar = cli_ch_process(cch, 0);
+
+		if (!ichar) {
+			if (bootretry_tstc_timeout())
+				return -2;	/* timed out */
+			if (first && timeout) {
+				u64 etime = endtick(timeout);
+
+				while (!tstc()) {	/* while no incoming data */
+					if (get_ticks() >= etime)
+						return -2;	/* timed out */
+					schedule();
+				}
+				first = 0;
 			}
-			first = 0;
+
+			ichar = getcmd_getch();
 		}
 
-		ichar = getcmd_getch();
+		ichar = cli_ch_process(cch, ichar);
 
 		/* ichar=0x0 when error occurs in U-Boot getc */
 		if (!ichar)
 			continue;
 
-		if ((ichar == '\n') || (ichar == '\r')) {
+		if (ichar == '\n') {
 			putc('\n');
 			break;
 		}
 
-		/*
-		 * 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 == '[' || ichar == 'O')
-					act = ESC_SAVE;
-			} 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 '2':
-				case '3':
-				case '4':
-				case '7':
-				case '8':
-					if (esc_save[1] == '[') {
-						/* see if next character is ~ */
-						act = ESC_SAVE;
-					}
-					break;
-				}
-			} else if (esc_len == 3) {
-				switch (ichar) {
-				case '~':
-					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 */
-					}
-					break;
-				case '0':
-					if (esc_save[2] == '2')
-						act = ESC_SAVE;
-					break;
-				}
-			} else if (esc_len == 4) {
-				switch (ichar) {
-				case '0':
-				case '1':
-					act = ESC_SAVE;
-					break;		/* bracketed paste */
-				}
-			} else if (esc_len == 5) {
-				if (ichar == '~') {	/* bracketed paste */
-					ichar = 0;
-					act = ESC_CONVERTED;
-				}
-			}
-			switch (act) {
-			case ESC_SAVE:
-				esc_save[esc_len++] = ichar;
-				continue;
-			case ESC_REJECT:
-				esc_save[esc_len++] = ichar;
-				cread_add_str(esc_save, esc_len, insert,
-					      &num, &eol_num, buf, *len);
-				esc_len = 0;
-				continue;
-			case ESC_CONVERTED:
-				esc_len = 0;
-				break;
-			}
-		}
-
 		switch (ichar) {
-		case 0x1b:
-			if (esc_len == 0) {
-				esc_save[esc_len] = ichar;
-				esc_len = 1;
-			} else {
-				puts("impossible condition #876\n");
-				esc_len = 0;
-			}
-			break;
-
 		case CTL_CH('a'):
 			BEGINNING_OF_LINE();
 			break;
@@ -470,8 +366,6 @@ static int cread_line(const char *const prompt, char *buf, unsigned int *len,
 		{
 			char *hline;
 
-			esc_len = 0;
-
 			if (ichar == CTL_CH('p'))
 				hline = hist_prev();
 			else