Apply scrollback patch

.suckless/st/config.h

@@ -191,6 +191,8 @@ static Shortcut shortcuts[] = {
 	{ TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+	{ MODKEY|ShiftMask,     XK_K,           kscrollup,      {.i = -1} },
+	{ MODKEY|ShiftMask,     XK_J,           kscrolldown,    {.i = -1} },
 };
 
 /*

.suckless/st/hb.c

@@ -0,0 +1,136 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <X11/Xft/Xft.h>
+#include <hb.h>
+#include <hb-ft.h>
+
+#include "st.h"
+
+void hbtransformsegment(XftFont *xfont, const Glyph *string, hb_codepoint_t *codepoints, int start, int length);
+hb_font_t *hbfindfont(XftFont *match);
+
+typedef struct {
+	XftFont *match;
+	hb_font_t *font;
+} HbFontMatch;
+
+static int hbfontslen = 0;
+static HbFontMatch *hbfontcache = NULL;
+
+void
+hbunloadfonts()
+{
+	for (int i = 0; i < hbfontslen; i++) {
+		hb_font_destroy(hbfontcache[i].font);
+		XftUnlockFace(hbfontcache[i].match);
+	}
+
+	if (hbfontcache != NULL) {
+		free(hbfontcache);
+		hbfontcache = NULL;
+	}
+	hbfontslen = 0;
+}
+
+hb_font_t *
+hbfindfont(XftFont *match)
+{
+	for (int i = 0; i < hbfontslen; i++) {
+		if (hbfontcache[i].match == match)
+			return hbfontcache[i].font;
+	}
+
+	/* Font not found in cache, caching it now. */
+	hbfontcache = realloc(hbfontcache, sizeof(HbFontMatch) * (hbfontslen + 1));
+	FT_Face face = XftLockFace(match);
+	hb_font_t *font = hb_ft_font_create(face, NULL);
+	if (font == NULL)
+		die("Failed to load Harfbuzz font.");
+
+	hbfontcache[hbfontslen].match = match;
+	hbfontcache[hbfontslen].font = font;
+	hbfontslen += 1;
+
+	return font;
+}
+
+void
+hbtransform(XftGlyphFontSpec *specs, const Glyph *glyphs, size_t len, int x, int y)
+{
+	int start = 0, length = 1, gstart = 0;
+	hb_codepoint_t *codepoints = calloc(len, sizeof(hb_codepoint_t));
+
+	for (int idx = 1, specidx = 1; idx < len; idx++) {
+		if (glyphs[idx].mode & ATTR_WDUMMY) {
+			length += 1;
+			continue;
+		}
+
+		if (specs[specidx].font != specs[start].font || ATTRCMP(glyphs[gstart], glyphs[idx]) || selected(x + idx, y) != selected(x + gstart, y)) {
+			hbtransformsegment(specs[start].font, glyphs, codepoints, gstart, length);
+
+			/* Reset the sequence. */
+			length = 1;
+			start = specidx;
+			gstart = idx;
+		} else {
+			length += 1;
+		}
+
+		specidx++;
+	}
+
+	/* EOL. */
+	hbtransformsegment(specs[start].font, glyphs, codepoints, gstart, length);
+
+	/* Apply the transformation to glyph specs. */
+	for (int i = 0, specidx = 0; i < len; i++) {
+		if (glyphs[i].mode & ATTR_WDUMMY)
+			continue;
+
+		if (codepoints[i] != specs[specidx].glyph)
+			((Glyph *)glyphs)[i].mode |= ATTR_LIGA;
+
+		specs[specidx++].glyph = codepoints[i];
+	}
+
+	free(codepoints);
+}
+
+void
+hbtransformsegment(XftFont *xfont, const Glyph *string, hb_codepoint_t *codepoints, int start, int length)
+{
+	hb_font_t *font = hbfindfont(xfont);
+	if (font == NULL)
+		return;
+
+	Rune rune;
+	ushort mode = USHRT_MAX;
+	hb_buffer_t *buffer = hb_buffer_create();
+	hb_buffer_set_direction(buffer, HB_DIRECTION_LTR);
+
+	/* Fill buffer with codepoints. */
+	for (int i = start; i < (start+length); i++) {
+		rune = string[i].u;
+		mode = string[i].mode;
+		if (mode & ATTR_WDUMMY)
+			rune = 0x0020;
+		hb_buffer_add_codepoints(buffer, &rune, 1, 0, 1);
+	}
+
+	/* Shape the segment. */
+	hb_shape(font, buffer, NULL, 0);
+
+	/* Get new glyph info. */
+	hb_glyph_info_t *info = hb_buffer_get_glyph_infos(buffer, NULL);
+
+	/* Write new codepoints. */
+	for (int i = 0; i < length; i++) {
+		hb_codepoint_t gid = info[i].codepoint;
+		codepoints[start+i] = gid;
+	}
+
+	/* Cleanup. */
+	hb_buffer_destroy(buffer);
+}

.suckless/st/hb.h

@@ -0,0 +1,7 @@
+#include <X11/Xft/Xft.h>
+#include <hb.h>
+#include <hb-ft.h>
+
+void hbunloadfonts();
+void hbtransform(XftGlyphFontSpec *, const Glyph *, size_t, int, int);
+

.suckless/st/st.c

@@ -35,6 +35,7 @@
 #define ESC_ARG_SIZ   16
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
+#define HISTSIZE      2000
 
 /* macros */
 #define IS_SET(flag)		((term.mode & (flag)) != 0)
@@ -42,6 +43,9 @@
 #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
 #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
 #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
+#define TLINE(y)		((y) < term.scr ? term.hist[((y) + term.histi - \
+				term.scr + HISTSIZE + 1) % HISTSIZE] : \
+				term.line[(y) - term.scr])
 
 enum term_mode {
 	MODE_WRAP        = 1 << 0,
@@ -115,6 +119,9 @@ typedef struct {
 	int col;      /* nb col */
 	Line *line;   /* screen */
 	Line *alt;    /* alternate screen */
+	Line hist[HISTSIZE]; /* history buffer */
+	int histi;    /* history index */
+	int scr;      /* scroll back */
 	int *dirty;   /* dirtyness of lines */
 	TCursor c;    /* cursor */
 	int ocx;      /* old cursor col */
@@ -184,8 +191,8 @@ static void tnewline(int);
 static void tputtab(int);
 static void tputc(Rune);
 static void treset(void);
-static void tscrollup(int, int);
+static void tscrollup(int, int, int);
-static void tscrolldown(int, int);
+static void tscrolldown(int, int, int);
 static void tsetattr(int *, int);
 static void tsetchar(Rune, Glyph *, int, int);
 static void tsetdirt(int, int);
@@ -414,10 +421,10 @@ tlinelen(int y)
 {
 	int i = term.col;
 
-	if (term.line[y][i - 1].mode & ATTR_WRAP)
+	if (TLINE(y)[i - 1].mode & ATTR_WRAP)
 		return i;
 
-	while (i > 0 && term.line[y][i - 1].u == ' ')
+	while (i > 0 && TLINE(y)[i - 1].u == ' ')
 		--i;
 
 	return i;
@@ -526,7 +533,7 @@ selsnap(int *x, int *y, int direction)
 		 * Snap around if the word wraps around at the end or
 		 * beginning of a line.
 		 */
-		prevgp = &term.line[*y][*x];
+		prevgp = &TLINE(*y)[*x];
 		prevdelim = ISDELIM(prevgp->u);
 		for (;;) {
 			newx = *x + direction;
@@ -541,14 +548,14 @@ selsnap(int *x, int *y, int direction)
 					yt = *y, xt = *x;
 				else
 					yt = newy, xt = newx;
-				if (!(term.line[yt][xt].mode & ATTR_WRAP))
+				if (!(TLINE(yt)[xt].mode & ATTR_WRAP))
 					break;
 			}
 
 			if (newx >= tlinelen(newy))
 				break;
 
-			gp = &term.line[newy][newx];
+			gp = &TLINE(newy)[newx];
 			delim = ISDELIM(gp->u);
 			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
 					|| (delim && gp->u != prevgp->u)))
@@ -569,14 +576,14 @@ selsnap(int *x, int *y, int direction)
 		*x = (direction < 0) ? 0 : term.col - 1;
 		if (direction < 0) {
 			for (; *y > 0; *y += direction) {
-				if (!(term.line[*y-1][term.col-1].mode
+				if (!(TLINE(*y-1)[term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
 			}
 		} else if (direction > 0) {
 			for (; *y < term.row-1; *y += direction) {
-				if (!(term.line[*y][term.col-1].mode
+				if (!(TLINE(*y)[term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
@@ -607,13 +614,13 @@ getsel(void)
 		}
 
 		if (sel.type == SEL_RECTANGULAR) {
-			gp = &term.line[y][sel.nb.x];
+			gp = &TLINE(y)[sel.nb.x];
 			lastx = sel.ne.x;
 		} else {
-			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
+			gp = &TLINE(y)[sel.nb.y == y ? sel.nb.x : 0];
 			lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
 		}
-		last = &term.line[y][MIN(lastx, linelen-1)];
+		last = &TLINE(y)[MIN(lastx, linelen-1)];
 		while (last >= gp && last->u == ' ')
 			--last;
 
@@ -848,6 +855,9 @@ void
 ttywrite(const char *s, size_t n, int may_echo)
 {
 	const char *next;
+	Arg arg = (Arg) { .i = term.scr };
+
+	kscrolldown(&arg);
 
 	if (may_echo && IS_SET(MODE_ECHO))
 		twrite(s, n, 1);
@@ -1059,13 +1069,53 @@ tswapscreen(void)
 }
 
 void
-tscrolldown(int orig, int n)
+kscrolldown(const Arg* a)
+{
+	int n = a->i;
+
+	if (n < 0)
+		n = term.row + n;
+
+	if (n > term.scr)
+		n = term.scr;
+
+	if (term.scr > 0) {
+		term.scr -= n;
+		selscroll(0, -n);
+		tfulldirt();
+	}
+}
+
+void
+kscrollup(const Arg* a)
+{
+	int n = a->i;
+
+	if (n < 0)
+		n = term.row + n;
+
+	if (term.scr <= HISTSIZE-n) {
+		term.scr += n;
+		selscroll(0, n);
+		tfulldirt();
+	}
+}
+
+void
+tscrolldown(int orig, int n, int copyhist)
 {
 	int i;
 	Line temp;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
+	if (copyhist) {
+		term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
+		temp = term.hist[term.histi];
+		term.hist[term.histi] = term.line[term.bot];
+		term.line[term.bot] = temp;
+	}
+
 	tsetdirt(orig, term.bot-n);
 	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
@@ -1075,17 +1125,28 @@ tscrolldown(int orig, int n)
 		term.line[i-n] = temp;
 	}
 
+	if (term.scr == 0)
 		selscroll(orig, n);
 }
 
 void
-tscrollup(int orig, int n)
+tscrollup(int orig, int n, int copyhist)
 {
 	int i;
 	Line temp;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
+	if (copyhist) {
+		term.histi = (term.histi + 1) % HISTSIZE;
+		temp = term.hist[term.histi];
+		term.hist[term.histi] = term.line[orig];
+		term.line[orig] = temp;
+	}
+
+	if (term.scr > 0 && term.scr < HISTSIZE)
+		term.scr = MIN(term.scr + n, HISTSIZE-1);
+
 	tclearregion(0, orig, term.col-1, orig+n-1);
 	tsetdirt(orig+n, term.bot);
 
@@ -1095,6 +1156,7 @@ tscrollup(int orig, int n)
 		term.line[i+n] = temp;
 	}
 
+	if (term.scr == 0)
 		selscroll(orig, -n);
 }
 
@@ -1124,7 +1186,7 @@ tnewline(int first_col)
 	int y = term.c.y;
 
 	if (y == term.bot) {
-		tscrollup(term.top, 1);
+		tscrollup(term.top, 1, 1);
 	} else {
 		y++;
 	}
@@ -1289,14 +1351,14 @@ void
 tinsertblankline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrolldown(term.c.y, n);
+		tscrolldown(term.c.y, n, 0);
 }
 
 void
 tdeleteline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrollup(term.c.y, n);
+		tscrollup(term.c.y, n, 0);
 }
 
 int32_t
@@ -1733,11 +1795,11 @@ csihandle(void)
 		break;
 	case 'S': /* SU -- Scroll <n> line up */
 		DEFAULT(csiescseq.arg[0], 1);
-		tscrollup(term.top, csiescseq.arg[0]);
+		tscrollup(term.top, csiescseq.arg[0], 0);
 		break;
 	case 'T': /* SD -- Scroll <n> line down */
 		DEFAULT(csiescseq.arg[0], 1);
-		tscrolldown(term.top, csiescseq.arg[0]);
+		tscrolldown(term.top, csiescseq.arg[0], 0);
 		break;
 	case 'L': /* IL -- Insert <n> blank lines */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2249,7 +2311,7 @@ eschandle(uchar ascii)
 		return 0;
 	case 'D': /* IND -- Linefeed */
 		if (term.c.y == term.bot) {
-			tscrollup(term.top, 1);
+			tscrollup(term.top, 1, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y+1);
 		}
@@ -2262,7 +2324,7 @@ eschandle(uchar ascii)
 		break;
 	case 'M': /* RI -- Reverse index */
 		if (term.c.y == term.top) {
-			tscrolldown(term.top, 1);
+			tscrolldown(term.top, 1, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y-1);
 		}
@@ -2472,7 +2534,7 @@ twrite(const char *buf, int buflen, int show_ctrl)
 void
 tresize(int col, int row)
 {
-	int i;
+	int i, j;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
 	int *bp;
@@ -2509,6 +2571,14 @@ tresize(int col, int row)
 	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
 	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
 
+	for (i = 0; i < HISTSIZE; i++) {
+		term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyph));
+		for (j = mincol; j < col; j++) {
+			term.hist[i][j] = term.c.attr;
+			term.hist[i][j].u = ' ';
+		}
+	}
+
 	/* resize each row to new width, zero-pad if needed */
 	for (i = 0; i < minrow; i++) {
 		term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
@@ -2567,7 +2637,7 @@ drawregion(int x1, int y1, int x2, int y2)
 			continue;
 
 		term.dirty[y] = 0;
-		xdrawline(term.line[y], x1, y, x2);
+		xdrawline(TLINE(y), x1, y, x2);
 	}
 }
 
@@ -2588,6 +2658,7 @@ draw(void)
 		cx--;
 
 	drawregion(0, 0, term.col, term.row);
+	if (term.scr == 0)
 		xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
 				term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
 	term.ocx = cx;

.suckless/st/st.h

@@ -81,6 +81,8 @@ void die(const char *, ...);
 void redraw(void);
 void draw(void);
 
+void kscrolldown(const Arg *);
+void kscrollup(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);