path: root/st-scrollback.diff

From 8bae501586ed77a624170937c8bd111153433f64 Mon Sep 17 00:00:00 2001
From: Jochen Sprickerhof <jochen@sprickerhof.de>
Date: Thu, 3 Oct 2013 09:35:32 +0200
Subject: [PATCH] Add scrollback buffer

Default keyboard shortcuts:
{ ShiftMask,		XK_Page_Up,	kscrollup,	{.i = -1} },
{ ShiftMask,		XK_Page_Down,	kscrolldown,	{.i = -1} },

Negative numbers scroll back by $LINES - i
---
 config.def.h |   3 ++
 st.c         | 116 ++++++++++++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 95 insertions(+), 24 deletions(-)

diff --git a/config.def.h b/config.def.h
index def6c9e..35cd624 100644
--- a/config.def.h
+++ b/config.def.h
@@ -7,6 +7,7 @@
  */
 static char font[] = "Liberation Mono:pixelsize=12:antialias=false:autohint=false";
 static int borderpx = 2;
+static int histsize = 2000;
 static char shell[] = "/bin/sh";
 
 /* Kerning / character bounding-box mutlipliers */
@@ -112,6 +113,8 @@ static Shortcut shortcuts[] = {
 	{ ShiftMask,		XK_Insert,	selpaste,	{.i =  0} },
 	{ MODKEY|ShiftMask,	XK_Insert,	clippaste,	{.i =  0} },
 	{ MODKEY,		XK_Num_Lock,	numlock,	{.i =  0} },
+	{ ShiftMask,		XK_Page_Up,	kscrollup,	{.i = -1} },
+	{ ShiftMask,		XK_Page_Down,	kscrolldown,	{.i = -1} },
 };
 
 /*
diff --git a/st.c b/st.c
index 50b58a7..7408fe4 100644
--- a/st.c
+++ b/st.c
@@ -84,6 +84,8 @@ char *argv0;
 #define TRUERED(x)       (((x) & 0xff0000) >> 8)
 #define TRUEGREEN(x)     (((x) & 0xff00))
 #define TRUEBLUE(x)      (((x) & 0xff) << 8)
+#define TLINE(y)         ((y) < term.scr ? term.hist[((y) + term.histi - term.scr \
+			+ histsize + 1) % histsize] : term.line[(y) - term.scr])
 
 
 #define VT102ID "\033[?6c"
@@ -220,6 +222,9 @@ typedef struct {
 	int col;      /* nb col */
 	Line *line;   /* screen */
 	Line *alt;    /* alternate screen */
+	Line *hist;   /* history buffer */
+	int histi;    /* history index */
+	int scr;      /* scroll back */
 	bool *dirty;  /* dirtyness of lines */
 	TCursor c;    /* cursor */
 	int top;      /* top    scroll limit */
@@ -309,6 +314,8 @@ typedef struct {
 
 /* function definitions used in config.h */
 static void clippaste(const Arg *);
+static void kscrolldown(const Arg *);
+static void kscrollup(const Arg *);
 static void numlock(const Arg *);
 static void selpaste(const Arg *);
 static void xzoom(const Arg *);
@@ -368,8 +375,8 @@ static void tputtab(bool);
 static void tputc(char *, int);
 static void treset(void);
 static int tresize(int, int);
-static void tscrollup(int, int);
-static void tscrolldown(int, int);
+static void tscrollup(int, int, bool);
+static void tscrolldown(int, int, bool);
 static void tsetattr(int*, int);
 static void tsetchar(char *, Glyph *, int, int);
 static void tsetscroll(int, int);
@@ -721,7 +728,7 @@ selsnap(int mode, int *x, int *y, int direction) {
 		 */
 		for(;;) {
 			if(direction < 0 && *x <= 0) {
-				if(*y > 0 && term.line[*y - 1][term.col-1].mode
+				if(*y > 0 && TLINE(*y - 1)[term.col-1].mode
 						& ATTR_WRAP) {
 					*y -= 1;
 					*x = term.col-1;
@@ -730,7 +737,7 @@ selsnap(int mode, int *x, int *y, int direction) {
 				}
 			}
 			if(direction > 0 && *x >= term.col-1) {
-				if(*y < term.row-1 && term.line[*y][*x].mode
+				if(*y < term.row-1 && TLINE(*y)[*x].mode
 						& ATTR_WRAP) {
 					*y += 1;
 					*x = 0;
@@ -739,13 +746,13 @@ selsnap(int mode, int *x, int *y, int direction) {
 				}
 			}
 
-			if(term.line[*y][*x+direction].mode & ATTR_WDUMMY) {
+			if(TLINE(*y)[*x+direction].mode & ATTR_WDUMMY) {
 				*x += direction;
 				continue;
 			}
 
 			if(strchr(worddelimiters,
-					term.line[*y][*x+direction].c[0])) {
+					TLINE(*y)[*x+direction].c[0])) {
 				break;
 			}
 
@@ -761,14 +768,14 @@ selsnap(int mode, int *x, int *y, int direction) {
 		*x = (direction < 0) ? 0 : term.col - 1;
 		if(direction < 0 && *y > 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 && *y < term.row-1) {
 			for(; *y < term.row; *y += direction) {
-				if(!(term.line[*y][term.col-1].mode
+				if(!(TLINE(*y)[term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
@@ -781,7 +788,7 @@ selsnap(int mode, int *x, int *y, int direction) {
 		 */
 		if(direction > 0) {
 			i = term.col;
-			while(--i > 0 && term.line[*y][i].c[0] == ' ')
+			while(--i > 0 && TLINE(*y)[i].c[0] == ' ')
 				/* nothing */;
 			if(i > 0 && i < *x)
 				*x = term.col - 1;
@@ -951,7 +958,7 @@ selcopy(void) {
 
 		/* append every set & selected glyph to the selection */
 		for(y = sel.nb.y; y < sel.ne.y + 1; y++) {
-			gp = &term.line[y][0];
+			gp = &TLINE(y)[0];
 			last = gp + term.col;
 
 			while(--last >= gp && !(selected(last - gp, y) && \
@@ -985,7 +992,7 @@ selcopy(void) {
 			 */
 			if(y == sel.ne.y) {
 				i = term.col;
-				while(--i > 0 && term.line[y][i].c[0] == ' ')
+				while(--i > 0 && TLINE(y)[i].c[0] == ' ')
 					/* nothing */;
 				ex = sel.ne.x;
 				if(sel.nb.y == sel.ne.y && sel.ne.x < sel.nb.x)
@@ -1290,10 +1297,16 @@ ttyread(void) {
 
 	/* keep any uncomplete utf8 char for the next call */
 	memmove(buf, ptr, buflen);
+	if(term.scr > 0 && term.scr < histsize-1)
+		term.scr++;
 }
 
 void
 ttywrite(const char *s, size_t n) {
+	Arg arg = (Arg){ .i = term.scr };
+
+	kscrolldown(&arg);
+
 	if(write(cmdfd, s, n) == -1)
 		die("write error on tty: %s\n", SERRNO);
 }
@@ -1418,12 +1431,50 @@ 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, bool 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;
+	}
+
 	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
 	for(i = term.bot; i >= orig+n; i--) {
@@ -1439,11 +1490,18 @@ tscrolldown(int orig, int n) {
 }
 
 void
-tscrollup(int orig, int n) {
+tscrollup(int orig, int n, bool 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;
+	}
+
 	tclearregion(0, orig, term.col-1, orig+n-1);
 
 	for(i = orig; i <= term.bot-n; i++) {
@@ -1492,7 +1550,7 @@ tnewline(int first_col) {
 	int y = term.c.y;
 
 	if(y == term.bot) {
-		tscrollup(term.top, 1);
+		tscrollup(term.top, 1, true);
 	} else {
 		y++;
 	}
@@ -1655,7 +1713,7 @@ tinsertblankline(int n) {
 	if(term.c.y < term.top || term.c.y > term.bot)
 		return;
 
-	tscrolldown(term.c.y, n);
+	tscrolldown(term.c.y, n, false);
 }
 
 void
@@ -1663,7 +1721,7 @@ tdeleteline(int n) {
 	if(term.c.y < term.top || term.c.y > term.bot)
 		return;
 
-	tscrollup(term.c.y, n);
+	tscrollup(term.c.y, n, false);
 }
 
 long
@@ -2053,11 +2111,11 @@ 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], false);
 		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], false);
 		break;
 	case 'L': /* IL -- Insert <n> blank lines */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2474,7 +2532,7 @@ tputc(char *c, int len) {
 				break;
 			case 'D': /* IND -- Linefeed */
 				if(term.c.y == term.bot) {
-					tscrollup(term.top, 1);
+					tscrollup(term.top, 1, true);
 				} else {
 					tmoveto(term.c.x, term.c.y+1);
 				}
@@ -2490,7 +2548,7 @@ tputc(char *c, int len) {
 				break;
 			case 'M': /* RI -- Reverse index */
 				if(term.c.y == term.top) {
-					tscrolldown(term.top, 1);
+					tscrolldown(term.top, 1, true);
 				} else {
 					tmoveto(term.c.x, term.c.y-1);
 				}
@@ -2576,7 +2634,7 @@ tputc(char *c, int len) {
 
 int
 tresize(int col, int row) {
-	int i;
+	int i, j;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
 	int slide = term.c.y - row + 1;
@@ -2609,9 +2667,18 @@ tresize(int col, int row) {
 	/* resize to new height */
 	term.line = xrealloc(term.line, row * sizeof(Line));
 	term.alt  = xrealloc(term.alt,  row * sizeof(Line));
+	term.hist  = xrealloc(term.hist,  histsize * sizeof(Line));
 	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;
+			memcpy(term.hist[i][j].c, " ", 2);
+		}
+	}
+
 	/* resize each row to new width, zero-pad if needed */
 	for(i = 0; i < minrow; i++) {
 		term.dirty[i] = 1;
@@ -3406,10 +3473,10 @@ drawregion(int x1, int y1, int x2, int y2) {
 
 		xtermclear(0, y, term.col, y);
 		term.dirty[y] = 0;
-		base = term.line[y][0];
+		base = TLINE(y)[0];
 		ic = ib = ox = 0;
 		for(x = x1; x < x2; x++) {
-			new = term.line[y][x];
+			new = TLINE(y)[x];
 			if(new.mode == ATTR_WDUMMY)
 				continue;
 			if(ena_sel && selected(x, y))
@@ -3432,7 +3499,8 @@ drawregion(int x1, int y1, int x2, int y2) {
 		if(ib > 0)
 			xdraws(buf, base, ox, y, ic, ib);
 	}
-	xdrawcursor();
+	if(term.scr == 0)
+		xdrawcursor();
 }
 
 void
-- 
1.8.4.rc3