• Completely overhaul prompt length calculation and

prompt display routines; make Emacs and Vi share
  code, permitting reducing of duplication and code
  removal as well as more consistent behaviour; put
  some common code into shared helper functions, too
• New x_adjust() logic (Emacs mode): when determining
  what portion of a line to render use a much more
  sophisticated algorithm and try to fill up ⅔ of the
  total screen width (with line and prompt both) also
  as wished from Steffen Daode Nurpmeso

check.t

@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.624 2013/07/25 18:07:44 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.625 2013/07/26 20:33:35 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -31,7 +31,7 @@
 # http://www.freebsd.org/cgi/cvsweb.cgi/src/tools/regression/bin/test/regress.sh?rev=HEAD
 
 expected-stdout:
-	@(#)MIRBSD KSH R47 2013/07/25
+	@(#)MIRBSD KSH R47 2013/07/26
 description:
 	Check version of shell.
 stdin:
@@ -40,7 +40,7 @@ name: KSH_VERSION
 category: shell:legacy-no
 ---
 expected-stdout:
-	@(#)LEGACY KSH R47 2013/07/25
+	@(#)LEGACY KSH R47 2013/07/26
 description:
 	Check version of legacy shell.
 stdin:

edit.c

@@ -28,7 +28,7 @@
 
 #ifndef MKSH_NO_CMDLINE_EDITING
 
-__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.267 2013/06/03 22:27:42 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.268 2013/07/26 20:33:37 tg Exp $");
 
 /*
  * in later versions we might use libtermcap for this, but since external
@@ -919,7 +919,6 @@ static bool x_adj_ok;
  */
 static int x_adj_done;		/* is incremented by x_adjust() */
 
-static int x_col;
 static int x_displen;
 static int x_arg;		/* general purpose arg */
 static bool x_arg_defaulted;	/* x_arg not explicitly set; defaulted to 1 */
@@ -944,9 +943,6 @@ static int x_curprefix;
 static char *macroptr;		/* bind key macro active? */
 #endif
 #if !MKSH_S_NOVI
-static int cur_col;		/* current column on line */
-static int pwidth;		/* width of prompt */
-static int prompt_trunc;	/* how much of prompt to truncate */
 static int winwidth;		/* width of window */
 static char *wbuf[2];		/* window buffers */
 static int wbuf_len;		/* length of window buffers (x_cols - 3) */
@@ -955,13 +951,16 @@ static char morec;		/* more character at right of window */
 static int lastref;		/* argument to last refresh() */
 static int holdlen;		/* length of holdbuf */
 #endif
-static bool prompt_redraw;	/* false if newline forced after prompt */
+static int pwidth;		/* width of prompt */
+static int prompt_trunc;	/* how much of prompt to truncate or -1 */
+static int x_col;		/* current column on line */
 
 static int x_ins(const char *);
 static void x_delete(size_t, bool);
 static size_t x_bword(void);
 static size_t x_fword(bool);
 static void x_goto(char *);
+static char *x_bs0(char *, char *);
 static void x_bs3(char **);
 static int x_size_str(char *);
 static int x_size2(char *, char **);
@@ -1170,20 +1169,14 @@ x_e_getmbc(char *sbuf)
 static void
 x_init_prompt(void)
 {
-	x_col = promptlen(prompt);
+	prompt_trunc = pprompt(prompt, 0);
-	x_adj_ok = true;
+	pwidth = prompt_trunc % x_cols;
-	prompt_redraw = true;
+	prompt_trunc -= pwidth;
-	if (x_col >= xx_cols)
+	if ((mksh_uari_t)pwidth > ((mksh_uari_t)x_cols - 3 - MIN_EDIT_SPACE)) {
-		x_col %= xx_cols;
+		/* force newline after prompt */
-	x_displen = xx_cols - 2 - x_col;
+		prompt_trunc = -1;
-	x_adj_done = 0;
+		pwidth = 0;
-
-	pprompt(prompt, 0);
-	if (x_displen < 1) {
-		x_col = 0;
-		x_displen = xx_cols - 2;
 		x_e_putc2('\n');
-		prompt_redraw = false;
 	}
 }
 
@@ -1202,8 +1195,10 @@ x_emacs(char *buf, size_t len)
 	x_histp = histptr + 1;
 	x_last_command = XFUNC_error;
 
-	xx_cols = x_cols;
 	x_init_prompt();
+	x_displen = (xx_cols = x_cols) - 2 - (x_col = pwidth);
+	x_adj_done = 0;
+	x_adj_ok = true;
 
 	x_histncp = NULL;
 	if (x_nextcmd >= 0) {
@@ -1561,11 +1556,7 @@ x_fword(bool move)
 static void
 x_goto(char *cp)
 {
-	if (cp >= xep)
+	cp = cp >= xep ? xep : x_bs0(cp, xbuf);
-		cp = xep;
-	else if (UTFMODE)
-		while ((cp > xbuf) && ((*cp & 0xC0) == 0x80))
-			--cp;
 	if (cp < xbp || cp >= utf_skipcols(xbp, x_displen)) {
 		/* we are heading off screen */
 		xcp = cp;
@@ -1581,16 +1572,22 @@ x_goto(char *cp)
 	}
 }
 
+static char *
+x_bs0(char *cp, char *lower_bound)
+{
+	if (UTFMODE)
+		while ((!lower_bound || (cp > lower_bound)) &&
+		    ((*(unsigned char *)cp & 0xC0) == 0x80))
+			--cp;
+	return (cp);
+}
+
 static void
 x_bs3(char **p)
 {
 	int i;
 
-	(*p)--;
+	*p = x_bs0((*p) - 1, NULL);
-	if (UTFMODE)
-		while (((unsigned char)**p & 0xC0) == 0x80)
-			(*p)--;
-
 	i = x_size2(*p, NULL);
 	while (i--)
 		x_e_putc2('\b');
@@ -2080,7 +2077,7 @@ x_cls(int c MKSH_A_UNUSED)
 static void
 x_redraw(int limit)
 {
-	int i, j, x_trunc = 0;
+	int i, j;
 	char *cp;
 
 	x_adj_ok = false;
@@ -2090,19 +2087,11 @@ x_redraw(int limit)
 		x_e_putc2('\r');
 	x_flush();
 	if (xbp == xbuf) {
-		x_col = promptlen(prompt);
+		if (prompt_trunc != -1)
-		if (x_col >= xx_cols)
+			pprompt(prompt, prompt_trunc);
-			x_trunc = (x_col / xx_cols) * xx_cols;
+		x_col = pwidth;
-		if (prompt_redraw)
-			pprompt(prompt, x_trunc);
 	}
-	if (x_col >= xx_cols)
-		x_col %= xx_cols;
 	x_displen = xx_cols - 2 - x_col;
-	if (x_displen < 1) {
-		x_col = 0;
-		x_displen = xx_cols - 2;
-	}
 	xlp_valid = false;
 	x_zots(xbp);
 	if (xbp != xbuf || xep > xlp)
@@ -2816,16 +2805,42 @@ do_complete(
 static void
 x_adjust(void)
 {
-	/* flag the fact that we were called. */
+	int col_left, n;
+
+	/* flag the fact that we were called */
 	x_adj_done++;
+
 	/*
-	 * we had a problem if the prompt length > xx_cols / 2
+	 * calculate the amount of columns we need to "go back"
+	 * from xcp to set xbp to (but never < xbuf) to 2/3 of
+	 * the display width; take care of pwidth though
 	 */
-	if ((xbp = xcp - (x_displen / 2)) < xbuf)
+	if ((col_left = xx_cols * 2 / 3) < MIN_EDIT_SPACE) {
-		xbp = xbuf;
+		/*
-	if (UTFMODE)
+		 * cowardly refuse to do anything
-		while ((xbp > xbuf) && ((*xbp & 0xC0) == 0x80))
+		 * if the available space is too small;
-			--xbp;
+		 * fall back to dumb pdksh code
+		 */
+		if ((xbp = xcp - (x_displen / 2)) < xbuf)
+			xbp = xbuf;
+		/* elide UTF-8 fixup as penalty */
+		goto x_adjust_out;
+	}
+
+	/* fix up xbp to character begin first */
+	xbp = x_bs0(xcp, xbuf);
+	/* walk backwards */
+	while (xbp > xbuf && col_left > 0) {
+		xbp = x_bs0(xbp - 1, xbuf);
+		col_left -= (n = x_size2(xbp, NULL));
+	}
+	/* check if we hit the prompt */
+	if (xbp == xbuf && xcp != xbuf && col_left > 0 && col_left < pwidth) {
+		/* so we did; force scrolling occurs */
+		xbp += utf_ptradj(xbp);
+	}
+
+ x_adjust_out:
 	xlp_valid = false;
 	x_redraw(xx_cols);
 	x_flush();
@@ -3517,18 +3532,8 @@ x_vi(char *buf, size_t len)
 	es->cursor = undo->cursor = 0;
 	es->winleft = undo->winleft = 0;
 
-	cur_col = promptlen(prompt);
+	x_init_prompt();
-	prompt_trunc = (cur_col / x_cols) * x_cols;
+	x_col = pwidth;
-	cur_col -= prompt_trunc;
-
-	pprompt(prompt, 0);
-	if ((mksh_uari_t)cur_col > (mksh_uari_t)x_cols - 3 - MIN_EDIT_SPACE) {
-		prompt_redraw = false;
-		cur_col = 0;
-		x_putc('\n');
-	} else
-		prompt_redraw = true;
-	pwidth = cur_col;
 
 	if (!wbuf_len || wbuf_len != x_cols - 3) {
 		wbuf_len = x_cols - 3;
@@ -5057,9 +5062,9 @@ redraw_line(bool newl)
 		x_putc('\r');
 		x_putc('\n');
 	}
-	if (prompt_redraw)
+	if (prompt_trunc != -1)
 		pprompt(prompt, prompt_trunc);
-	cur_col = pwidth;
+	x_col = pwidth;
 	morec = ' ';
 }
 
@@ -5177,10 +5182,10 @@ display(char *wb1, char *wb2, int leftside)
 	twb2 = wb2;
 	while (cnt--) {
 		if (*twb1 != *twb2) {
-			if (cur_col != col)
+			if (x_col != col)
 				ed_mov_opt(col, wb1);
 			x_putc(*twb1);
-			cur_col++;
+			x_col++;
 		}
 		twb1++;
 		twb2++;
@@ -5201,34 +5206,34 @@ display(char *wb1, char *wb2, int leftside)
 	if (mc != morec) {
 		ed_mov_opt(pwidth + winwidth + 1, wb1);
 		x_putc(mc);
-		cur_col++;
+		x_col++;
 		morec = mc;
 	}
-	if (cur_col != ncol)
+	if (x_col != ncol)
 		ed_mov_opt(ncol, wb1);
 }
 
 static void
 ed_mov_opt(int col, char *wb)
 {
-	if (col < cur_col) {
+	if (col < x_col) {
-		if (col + 1 < cur_col - col) {
+		if (col + 1 < x_col - col) {
 			x_putc('\r');
-			if (prompt_redraw)
+			if (prompt_trunc != -1)
 				pprompt(prompt, prompt_trunc);
-			cur_col = pwidth;
+			x_col = pwidth;
-			while (cur_col++ < col)
+			while (x_col++ < col)
 				x_putcf(*wb++);
 		} else {
-			while (cur_col-- > col)
+			while (x_col-- > col)
 				x_putc('\b');
 		}
 	} else {
-		wb = &wb[cur_col - pwidth];
+		wb = &wb[x_col - pwidth];
-		while (cur_col++ < col)
+		while (x_col++ < col)
 			x_putcf(*wb++);
 	}
-	cur_col = col;
+	x_col = col;
 }
 
 

lex.c

@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/lex.c,v 1.186 2013/06/01 00:15:57 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/lex.c,v 1.187 2013/07/26 20:33:38 tg Exp $");
 
 /*
  * states while lexing word
@@ -102,8 +102,6 @@ static void gethere(bool);
 static Lex_state *push_state_i(State_info *, Lex_state *);
 static Lex_state *pop_state_i(State_info *, Lex_state *);
 
-static int dopprompt(const char *, int, bool);
-
 static int backslash_skip;
 static int ignore_backslash_newline;
 
@@ -1520,8 +1518,8 @@ set_prompt(int to, Source *s)
 	}
 }
 
-static int
+int
-dopprompt(const char *cp, int ntruncate, bool doprint)
+pprompt(const char *cp, int ntruncate)
 {
 	int columns = 0, lines = 0;
 	bool indelimit = false;
@@ -1554,35 +1552,21 @@ dopprompt(const char *cp, int ntruncate, bool doprint)
 		else if (UTFMODE && ((unsigned char)*cp > 0x7F)) {
 			const char *cp2;
 			columns += utf_widthadj(cp, &cp2);
-			if (doprint && (indelimit ||
+			if (indelimit ||
-			    (ntruncate < (x_cols * lines + columns))))
+			    (ntruncate < (x_cols * lines + columns)))
 				shf_write(cp, cp2 - cp, shl_out);
 			cp = cp2 - /* loop increment */ 1;
 			continue;
 		} else
 			columns++;
-		if (doprint && (*cp != delimiter) &&
+		if ((*cp != delimiter) &&
 		    (indelimit || (ntruncate < (x_cols * lines + columns))))
 			shf_putc(*cp, shl_out);
 	}
-	if (doprint)
+	shf_flush(shl_out);
-		shf_flush(shl_out);
 	return (x_cols * lines + columns);
 }
 
-
-void
-pprompt(const char *cp, int ntruncate)
-{
-	dopprompt(cp, ntruncate, true);
-}
-
-int
-promptlen(const char *cp)
-{
-	return (dopprompt(cp, 0, false));
-}
-
 /*
  * Read the variable part of a ${...} expression (i.e. up to but not
  * including the :[-+?=#%] or close-brace).

sh.h

@@ -164,9 +164,9 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.662 2013/07/25 18:07:47 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.663 2013/07/26 20:33:39 tg Exp $");
 #endif
-#define MKSH_VERSION "R47 2013/07/25"
+#define MKSH_VERSION "R47 2013/07/26"
 
 /* arithmetic types: C implementation */
 #if !HAVE_CAN_INTTYPES
@@ -444,8 +444,6 @@ extern int wcwidth(__WCHAR_TYPE__);
 #define MAGIC		(7)	/* prefix for *?[!{,} during expand */
 #define ISMAGIC(c)	((unsigned char)(c) == MAGIC)
 
-#define LINE		4096	/* input line size */
-
 EXTERN const char *safe_prompt; /* safe prompt if PS1 substitution fails */
 
 #ifdef MKSH_LEGACY_MODE
@@ -992,6 +990,8 @@ EXTERN uint32_t builtin_flag;
 /* current working directory */
 EXTERN char	*current_wd;
 
+/* input line size */
+#define LINE		4096
 /*
  * Minimum required space to work with on a line - if the prompt leaves
  * less space than this on a line, the prompt is truncated.
@@ -1837,8 +1837,7 @@ void yyerror(const char *, ...)
     MKSH_A_FORMAT(__printf__, 1, 2);
 Source *pushs(int, Area *);
 void set_prompt(int, Source *);
-void pprompt(const char *, int);
+int pprompt(const char *, int);
-int promptlen(const char *);
 /* main.c */
 int include(const char *, int, const char **, bool);
 int command(const char *, int);