Merge branch '2023-10-12-expo-add-support-for-edting-lines-of-text'

To quote the author:
So far expo only supports menus. These are quite flexible for various
kinds of settings, but cannot deal with free-form input, such as a
serial number or a machine name.

This series adds support for a textline object, which is a single line
of text. It has a maximum length and its value is stored within the expo
structure.

U-Boot already has a command-line editor which provides most of the
features needed by expo. But the code runs in its own loop and only
returns when the line is finished. This is not suitable for expo, which
must handle a keypress at a time, returning to its caller after each
one.

In order to use the CLI code, some significant refactoring is included
here. This mostly involves moving the internal loop of the CLI to a
separate function and recording its state in a struct, just as was done
for single keypresses some time back. A minor addition is support for
Ctrl-W to delete a word, since strangely this is currently only present
in the simple version.

The video-console system provides most of the features needed by
testline, but a few things are missing. This series provides:

- primitive cursor support so the user can see where he is typing
- saving and restoring of the text-entry context, so that expo can allow
  the user to continue where he left off, including deleting previously
  entered characters correctly (for Truetype)
- obtaining the nominal width of a string of n characters, so that a
  suitable width can be chosen for the textline object

Note that no support is provided for clearing the cursor. This was
addressed in a previous series[1] which could perhaps be rebased. For
this implementation, the cursor is therefore not enabled for the normal
command line, only for expo.

Reading and writing textline objects is supported for FDT and
environment, but not for CMOS RAM, since it would likely use too much
RAM to store a string.

In terms of code size, the overall size increase is 180 bytes for
Thumb02 boards, 160 of whcih is the addition of Ctrl-W to delete a word.

[1] https://patchwork.ozlabs.org/project/uboot/list/?series=280178&state=*

1 files changed, 292 insertions, 206 deletions

diff --git a/common/cli_readline.c b/common/cli_readline.c
index e83743e90c9..06b8d465044 100644
--- a/common/cli_readline.c
+++ b/common/cli_readline.c
@@ -89,6 +89,14 @@ static char hist_lines[HIST_MAX][HIST_SIZE + 1];	/* Save room for NULL */
 
 #define add_idx_minus_one() ((hist_add_idx == 0) ? hist_max : hist_add_idx-1)
 
+static void getcmd_putchars(int count, int ch)
+{
+	int i;
+
+	for (i = 0; i < count; i++)
+		getcmd_putch(ch);
+}
+
 static void hist_init(void)
 {
 	int i;
@@ -160,11 +168,10 @@ static char *hist_next(void)
 	return ret;
 }
 
-#ifndef CONFIG_CMDLINE_EDITING
-static void cread_print_hist_list(void)
+void cread_print_hist_list(void)
 {
 	int i;
-	unsigned long n;
+	uint n;
 
 	n = hist_num - hist_max;
 
@@ -179,36 +186,35 @@ static void cread_print_hist_list(void)
 		i++;
 	}
 }
-#endif /* CONFIG_CMDLINE_EDITING */
 
 #define BEGINNING_OF_LINE() {			\
-	while (num) {				\
+	while (cls->num) {			\
 		getcmd_putch(CTL_BACKSPACE);	\
-		num--;				\
+		cls->num--;			\
 	}					\
 }
 
 #define ERASE_TO_EOL() {				\
-	if (num < eol_num) {				\
-		printf("%*s", (int)(eol_num - num), ""); \
+	if (cls->num < cls->eol_num) {		\
+		printf("%*s", (int)(cls->eol_num - cls->num), ""); \
 		do {					\
 			getcmd_putch(CTL_BACKSPACE);	\
-		} while (--eol_num > num);		\
+		} while (--cls->eol_num > cls->num);	\
 	}						\
 }
 
-#define REFRESH_TO_EOL() {			\
-	if (num < eol_num) {			\
-		wlen = eol_num - num;		\
-		putnstr(buf + num, wlen);	\
-		num = eol_num;			\
-	}					\
+#define REFRESH_TO_EOL() {				\
+	if (cls->num < cls->eol_num) {			\
+		uint wlen = cls->eol_num - cls->num;	\
+		putnstr(buf + cls->num, wlen);		\
+		cls->num = cls->eol_num;		\
+	}						\
 }
 
-static void cread_add_char(char ichar, int insert, unsigned long *num,
-	       unsigned long *eol_num, char *buf, unsigned long len)
+static void cread_add_char(char ichar, int insert, uint *num,
+			   uint *eol_num, char *buf, uint len)
 {
-	unsigned long wlen;
+	uint wlen;
 
 	/* room ??? */
 	if (insert || *num == *eol_num) {
@@ -239,8 +245,7 @@ static void cread_add_char(char ichar, int insert, unsigned long *num,
 }
 
 static void cread_add_str(char *str, int strsize, int insert,
-			  unsigned long *num, unsigned long *eol_num,
-			  char *buf, unsigned long len)
+			  uint *num, uint *eol_num, char *buf, uint len)
 {
 	while (strsize--) {
 		cread_add_char(*str, insert, num, eol_num, buf, len);
@@ -248,121 +253,115 @@ 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)
+int cread_line_process_ch(struct cli_line_state *cls, char ichar)
 {
-	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 init_len = strlen(buf);
-	int first = 1;
+	char *buf = cls->buf;
 
-	cli_ch_init(cch);
-
-	if (init_len)
-		cread_add_str(buf, init_len, 1, &num, &eol_num, buf, *len);
-
-	while (1) {
-		/* Check for saved characters */
-		ichar = cli_ch_process(cch, 0);
+	/* ichar=0x0 when error occurs in U-Boot getc */
+	if (!ichar)
+		return -EAGAIN;
 
-		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;
-			}
+	if (ichar == '\n') {
+		putc('\n');
+		buf[cls->eol_num] = '\0';	/* terminate the string */
+		return 0;
+	}
 
-			ichar = getcmd_getch();
-			ichar = cli_ch_process(cch, ichar);
+	switch (ichar) {
+	case CTL_CH('a'):
+		BEGINNING_OF_LINE();
+		break;
+	case CTL_CH('c'):	/* ^C - break */
+		*buf = '\0';	/* discard input */
+		return -EINTR;
+	case CTL_CH('f'):
+		if (cls->num < cls->eol_num) {
+			getcmd_putch(buf[cls->num]);
+			cls->num++;
 		}
-
-		/* ichar=0x0 when error occurs in U-Boot getc */
-		if (!ichar)
-			continue;
-
-		if (ichar == '\n') {
-			putc('\n');
-			break;
+		break;
+	case CTL_CH('b'):
+		if (cls->num) {
+			getcmd_putch(CTL_BACKSPACE);
+			cls->num--;
 		}
-
-		switch (ichar) {
-		case CTL_CH('a'):
-			BEGINNING_OF_LINE();
-			break;
-		case CTL_CH('c'):	/* ^C - break */
-			*buf = '\0';	/* discard input */
-			return -1;
-		case CTL_CH('f'):
-			if (num < eol_num) {
-				getcmd_putch(buf[num]);
-				num++;
-			}
-			break;
-		case CTL_CH('b'):
-			if (num) {
-				getcmd_putch(CTL_BACKSPACE);
-				num--;
+		break;
+	case CTL_CH('d'):
+		if (cls->num < cls->eol_num) {
+			uint wlen;
+
+			wlen = cls->eol_num - cls->num - 1;
+			if (wlen) {
+				memmove(&buf[cls->num], &buf[cls->num + 1],
+					wlen);
+				putnstr(buf + cls->num, wlen);
 			}
-			break;
-		case CTL_CH('d'):
-			if (num < eol_num) {
-				wlen = eol_num - num - 1;
-				if (wlen) {
-					memmove(&buf[num], &buf[num+1], wlen);
-					putnstr(buf + num, wlen);
-				}
 
-				getcmd_putch(' ');
-				do {
-					getcmd_putch(CTL_BACKSPACE);
-				} while (wlen--);
-				eol_num--;
-			}
-			break;
-		case CTL_CH('k'):
-			ERASE_TO_EOL();
-			break;
-		case CTL_CH('e'):
-			REFRESH_TO_EOL();
-			break;
-		case CTL_CH('o'):
-			insert = !insert;
-			break;
-		case CTL_CH('x'):
-		case CTL_CH('u'):
-			BEGINNING_OF_LINE();
-			ERASE_TO_EOL();
-			break;
-		case DEL:
-		case DEL7:
-		case 8:
-			if (num) {
-				wlen = eol_num - num;
-				num--;
-				memmove(&buf[num], &buf[num+1], wlen);
+			getcmd_putch(' ');
+			do {
 				getcmd_putch(CTL_BACKSPACE);
-				putnstr(buf + num, wlen);
-				getcmd_putch(' ');
-				do {
-					getcmd_putch(CTL_BACKSPACE);
-				} while (wlen--);
-				eol_num--;
-			}
-			break;
-		case CTL_CH('p'):
-		case CTL_CH('n'):
-		{
+			} while (wlen--);
+			cls->eol_num--;
+		}
+		break;
+	case CTL_CH('k'):
+		ERASE_TO_EOL();
+		break;
+	case CTL_CH('e'):
+		REFRESH_TO_EOL();
+		break;
+	case CTL_CH('o'):
+		cls->insert = !cls->insert;
+		break;
+	case CTL_CH('w'):
+		if (cls->num) {
+			uint base, wlen;
+
+			for (base = cls->num - 1;
+			     base >= 0 && buf[base] == ' ';)
+				base--;
+			for (; base > 0 && buf[base - 1] != ' ';)
+				base--;
+
+			/* now delete chars from base to cls->num */
+			wlen = cls->num - base;
+			cls->eol_num -= wlen;
+			memmove(&buf[base], &buf[cls->num],
+				cls->eol_num - base + 1);
+			cls->num = base;
+			getcmd_putchars(wlen, CTL_BACKSPACE);
+			puts(buf + base);
+			getcmd_putchars(wlen, ' ');
+			getcmd_putchars(wlen + cls->eol_num - cls->num,
+					CTL_BACKSPACE);
+		}
+		break;
+	case CTL_CH('x'):
+	case CTL_CH('u'):
+		BEGINNING_OF_LINE();
+		ERASE_TO_EOL();
+		break;
+	case DEL:
+	case DEL7:
+	case 8:
+		if (cls->num) {
+			uint wlen;
+
+			wlen = cls->eol_num - cls->num;
+			cls->num--;
+			memmove(&buf[cls->num], &buf[cls->num + 1], wlen);
+			getcmd_putch(CTL_BACKSPACE);
+			putnstr(buf + cls->num, wlen);
+			getcmd_putch(' ');
+			do {
+				getcmd_putch(CTL_BACKSPACE);
+			} while (wlen--);
+			cls->eol_num--;
+		}
+		break;
+	case CTL_CH('p'):
+	case CTL_CH('n'):
+		if (cls->history) {
 			char *hline;
 
 			if (ichar == CTL_CH('p'))
@@ -372,7 +371,7 @@ static int cread_line(const char *const prompt, char *buf, unsigned int *len,
 
 			if (!hline) {
 				getcmd_cbeep();
-				continue;
+				break;
 			}
 
 			/* nuke the current line */
@@ -384,39 +383,106 @@ static int cread_line(const char *const prompt, char *buf, unsigned int *len,
 
 			/* copy new line into place and display */
 			strcpy(buf, hline);
-			eol_num = strlen(buf);
+			cls->eol_num = strlen(buf);
 			REFRESH_TO_EOL();
-			continue;
+			break;
 		}
-#ifdef CONFIG_AUTO_COMPLETE
-		case '\t': {
+		break;
+	case '\t':
+		if (IS_ENABLED(CONFIG_AUTO_COMPLETE) && cls->cmd_complete) {
 			int num2, col;
 
 			/* do not autocomplete when in the middle */
-			if (num < eol_num) {
+			if (cls->num < cls->eol_num) {
 				getcmd_cbeep();
 				break;
 			}
 
-			buf[num] = '\0';
-			col = strlen(prompt) + eol_num;
-			num2 = num;
-			if (cmd_auto_complete(prompt, buf, &num2, &col)) {
-				col = num2 - num;
-				num += col;
-				eol_num += col;
+			buf[cls->num] = '\0';
+			col = strlen(cls->prompt) + cls->eol_num;
+			num2 = cls->num;
+			if (cmd_auto_complete(cls->prompt, buf, &num2, &col)) {
+				col = num2 - cls->num;
+				cls->num += col;
+				cls->eol_num += col;
 			}
 			break;
 		}
-#endif
-		default:
-			cread_add_char(ichar, insert, &num, &eol_num, buf,
-				       *len);
-			break;
+		fallthrough;
+	default:
+		cread_add_char(ichar, cls->insert, &cls->num, &cls->eol_num,
+			       buf, cls->len);
+		break;
+	}
+
+	/*
+	 * keep the string terminated...if we added a char at the end then we
+	 * want a \0 after it
+	 */
+	buf[cls->eol_num] = '\0';
+
+	return -EAGAIN;
+}
+
+void cli_cread_init(struct cli_line_state *cls, char *buf, uint buf_size)
+{
+	int init_len = strlen(buf);
+
+	memset(cls, '\0', sizeof(struct cli_line_state));
+	cls->insert = true;
+	cls->buf = buf;
+	cls->len = buf_size;
+
+	if (init_len)
+		cread_add_str(buf, init_len, 0, &cls->num, &cls->eol_num, buf,
+			      buf_size);
+}
+
+static int cread_line(const char *const prompt, char *buf, unsigned int *len,
+		      int timeout)
+{
+	struct cli_ch_state s_cch, *cch = &s_cch;
+	struct cli_line_state s_cls, *cls = &s_cls;
+	char ichar;
+	int first = 1;
+
+	cli_ch_init(cch);
+	cli_cread_init(cls, buf, *len);
+	cls->prompt = prompt;
+	cls->history = true;
+	cls->cmd_complete = true;
+
+	while (1) {
+		int ret;
+
+		/* 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;
+			}
+
+			ichar = getcmd_getch();
+			ichar = cli_ch_process(cch, ichar);
 		}
+
+		ret = cread_line_process_ch(cls, ichar);
+		if (ret == -EINTR)
+			return -1;
+		else if (!ret)
+			break;
 	}
-	*len = eol_num;
-	buf[eol_num] = '\0';	/* lose the newline */
+	*len = cls->eol_num;
 
 	if (buf[0] && buf[0] != CREAD_HIST_CHAR)
 		cread_add_to_hist(buf);
@@ -425,6 +491,18 @@ static int cread_line(const char *const prompt, char *buf, unsigned int *len,
 	return 0;
 }
 
+#else /* !CONFIG_CMDLINE_EDITING */
+
+static inline void hist_init(void)
+{
+}
+
+static int cread_line(const char *const prompt, char *buf, unsigned int *len,
+		      int timeout)
+{
+	return 0;
+}
+
 #endif /* CONFIG_CMDLINE_EDITING */
 
 /****************************************************************************/
@@ -440,41 +518,22 @@ int cli_readline(const char *const prompt)
 	return cli_readline_into_buffer(prompt, console_buffer, 0);
 }
 
-
-int cli_readline_into_buffer(const char *const prompt, char *buffer,
-			     int timeout)
+/**
+ * cread_line_simple() - Simple (small) command-line reader
+ *
+ * This supports only basic editing, with no cursor movement
+ *
+ * @prompt: Prompt to display
+ * @p: Text buffer to edit
+ * Return: length of text buffer, or -1 if input was cannncelled (Ctrl-C)
+ */
+static int cread_line_simple(const char *const prompt, char *p)
 {
-	char *p = buffer;
-#ifdef CONFIG_CMDLINE_EDITING
-	unsigned int len = CONFIG_SYS_CBSIZE;
-	int rc;
-	static int initted;
-
-	/*
-	 * History uses a global array which is not
-	 * writable until after relocation to RAM.
-	 * Revert to non-history version if still
-	 * running from flash.
-	 */
-	if (gd->flags & GD_FLG_RELOC) {
-		if (!initted) {
-			hist_init();
-			initted = 1;
-		}
-
-		if (prompt)
-			puts(prompt);
-
-		rc = cread_line(prompt, p, &len, timeout);
-		return rc < 0 ? rc : len;
-
-	} else {
-#endif	/* CONFIG_CMDLINE_EDITING */
 	char *p_buf = p;
-	int	n = 0;				/* buffer index		*/
-	int	plen = 0;			/* prompt length	*/
-	int	col;				/* output column cnt	*/
-	char	c;
+	int n = 0;		/* buffer index */
+	int plen = 0;		/* prompt length */
+	int col;		/* output column cnt */
+	char c;
 
 	/* print prompt */
 	if (prompt) {
@@ -528,14 +587,15 @@ int cli_readline_into_buffer(const char *const prompt, char *buffer,
 			continue;
 
 		default:
-			/*
-			 * Must be a normal character then
-			 */
-			if (n < CONFIG_SYS_CBSIZE-2) {
-				if (c == '\t') {	/* expand TABs */
-#ifdef CONFIG_AUTO_COMPLETE
+			/* Must be a normal character then */
+			if (n >= CONFIG_SYS_CBSIZE - 2) { /* Buffer full */
+				putc('\a');
+				break;
+			}
+			if (c == '\t') {	/* expand TABs */
+				if (IS_ENABLED(CONFIG_AUTO_COMPLETE)) {
 					/*
-					 * if auto completion triggered just
+					 * if auto-completion triggered just
 					 * continue
 					 */
 					*p = '\0';
@@ -545,29 +605,55 @@ int cli_readline_into_buffer(const char *const prompt, char *buffer,
 						p = p_buf + n;	/* reset */
 						continue;
 					}
-#endif
-					puts(tab_seq + (col & 07));
-					col += 8 - (col & 07);
-				} else {
-					char __maybe_unused buf[2];
-
-					/*
-					 * Echo input using puts() to force an
-					 * LCD flush if we are using an LCD
-					 */
-					++col;
-					buf[0] = c;
-					buf[1] = '\0';
-					puts(buf);
 				}
-				*p++ = c;
-				++n;
-			} else {			/* Buffer full */
-				putc('\a');
+				puts(tab_seq + (col & 07));
+				col += 8 - (col & 07);
+			} else {
+				char __maybe_unused buf[2];
+
+				/*
+				 * Echo input using puts() to force an LCD
+				 * flush if we are using an LCD
+				 */
+				++col;
+				buf[0] = c;
+				buf[1] = '\0';
+				puts(buf);
 			}
+			*p++ = c;
+			++n;
+			break;
 		}
 	}
-#ifdef CONFIG_CMDLINE_EDITING
+}
+
+int cli_readline_into_buffer(const char *const prompt, char *buffer,
+			     int timeout)
+{
+	char *p = buffer;
+	uint len = CONFIG_SYS_CBSIZE;
+	int rc;
+	static int initted;
+
+	/*
+	 * History uses a global array which is not
+	 * writable until after relocation to RAM.
+	 * Revert to non-history version if still
+	 * running from flash.
+	 */
+	if (IS_ENABLED(CONFIG_CMDLINE_EDITING) && (gd->flags & GD_FLG_RELOC)) {
+		if (!initted) {
+			hist_init();
+			initted = 1;
+		}
+
+		if (prompt)
+			puts(prompt);
+
+		rc = cread_line(prompt, p, &len, timeout);
+		return rc < 0 ? rc : len;
+
+	} else {
+		return cread_line_simple(prompt, p);
 	}
-#endif
 }