From 427819910184a7174391c2e688da6b89634045ec Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicm@openbsd.org>
Date: Tue, 15 Sep 2009 15:14:09 +0000
Subject: [PATCH] Stick line length to what is actually used (removing an
 optimization that allowed it to be bigger), and use clear line/EOL sequences
 rather than spaces in copy/scroll mode.

This fixes xterm copy/paste from tmux which treats trailing spaces differently
from clearing a line with the escape sequences. Reported by martynas@.
---
 grid.c         | 24 ++++++++++--------------
 screen-write.c | 43 ++++++++++++++++++++++++++++++-------------
 2 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/grid.c b/grid.c
index b79e8843..6e01aa7c 100644
--- a/grid.c
+++ b/grid.c
@@ -189,22 +189,15 @@ grid_scroll_line(struct grid *gd)
 
 /* Expand line to fit to cell. */
 void
-grid_expand_line(struct grid *gd, u_int py, u_int wantx)
+grid_expand_line(struct grid *gd, u_int py, u_int sx)
 {
 	struct grid_line	*gl;
-	u_int			 xx, sx;
+	u_int			 xx;
 
 	gl = &gd->linedata[py];
-	if (wantx <= gl->cellsize)
+	if (sx <= gl->cellsize)
 		return;
 
-	if (gl->cellsize > gd->sx / 2)
-		sx = gd->sx;
-	else {
-		sx = gl->cellsize + 1;
-		while (sx < wantx)
-			sx *= 2;
-	}
 	gl->celldata = xrealloc(gl->celldata, sx, sizeof *gl->celldata);
 	for (xx = gl->cellsize; xx < sx; xx++)
 		grid_put_cell(gd, xx, py, &grid_default_cell);
@@ -307,10 +300,7 @@ grid_set_utf8(
 	grid_put_utf8(gd, px, py, gc);
 }
 
-/*
- * Clear area. Note this is different from a fill as it just omits unallocated
- * cells.
- */
+/* Clear area. */
 void
 grid_clear(struct grid *gd, u_int px, u_int py, u_int nx, u_int ny)
 {
@@ -336,6 +326,12 @@ grid_clear(struct grid *gd, u_int px, u_int py, u_int nx, u_int ny)
 		return;
 
 	for (yy = py; yy < py + ny; yy++) {
+		if (px >= gd->linedata[yy].cellsize)
+			continue;
+		if (px + nx >= gd->linedata[yy].cellsize) {
+			gd->linedata[yy].cellsize = px;
+			continue;
+		}
 		for (xx = px; xx < px + nx; xx++) {
 			if (xx >= gd->linedata[yy].cellsize)
 				break;
diff --git a/screen-write.c b/screen-write.c
index dba5f708..507c527b 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -371,25 +371,42 @@ screen_write_copy(struct screen_write_ctx *ctx,
 	struct grid_line	*gl;
 	const struct grid_cell	*gc;
 	u_char			*udata;
-	u_int		 	 xx, yy, cx, cy;
+	u_int		 	 xx, yy, cx, cy, ax, bx;
 
 	cx = s->cx;
 	cy = s->cy;
 	for (yy = py; yy < py + ny; yy++) {
 		gl = &gd->linedata[yy];
-		for (xx = px; xx < px + nx; xx++) {
- 			udata = NULL;
-
-			if (xx >= gl->cellsize || yy >= gd->hsize + gd->sy)
-				gc = &grid_default_cell;
-			else {
-				gc = &gl->celldata[xx];
-				if (gc->flags & GRID_FLAG_UTF8)
-					udata = gl->utf8data[xx].data;
+		if (yy < gd->hsize + gd->sy) {
+			/*
+			 * Find start and end position and copy between
+			 * them. Limit to the real end of the line then use a
+			 * clear EOL only if copying to the end, otherwise
+			 * could overwrite whatever is there already.
+			 */
+			if (px > gl->cellsize)
+				ax = gl->cellsize;
+			else
+				ax = px;
+			if (px + nx == gd->sx && px + nx > gl->cellsize)
+				bx = gl->cellsize;
+			else
+				bx = px + nx;
+			for (xx = ax; xx < bx; xx++) {
+				udata = NULL;
+				if (xx >= gl->cellsize)
+					gc = &grid_default_cell;
+				else {
+					gc = &gl->celldata[xx];
+					if (gc->flags & GRID_FLAG_UTF8)
+						udata = gl->utf8data[xx].data;
+				}
+				screen_write_cell(ctx, gc, udata);
 			}
-
-			screen_write_cell(ctx, gc, udata);
-		}
+			if (px + nx == gd->sx && px + nx > gl->cellsize)
+				screen_write_clearendofline(ctx);
+		} else
+ 			screen_write_clearline(ctx);
 		cy++;
 		screen_write_cursormove(ctx, cx, cy);
 	}