Collect up line clears like text within the available data so we don't

need to flush everything.

screen-write.c

@@ -25,6 +25,10 @@
 
 static void	screen_write_collect_clear(struct screen_write_ctx *, u_int,
 		    u_int);
+static int	screen_write_collect_clear_end(struct screen_write_ctx *, u_int,
+		    u_int, u_int);
+static int	screen_write_collect_clear_start(struct screen_write_ctx *, u_int,
+		    u_int, u_int);
 static void	screen_write_collect_scroll(struct screen_write_ctx *);
 static void	screen_write_collect_flush(struct screen_write_ctx *, int,
 		    const char *);
@@ -42,8 +46,12 @@ struct screen_write_collect_item {
 	u_int			 x;
 	int			 wrapped;
 
+	enum { TEXT, CLEAR, CLEAR_END, CLEAR_START } type;
 	u_int			 used;
+	union {
+		u_int		 bg;
 		char		 data[256];
+	};
 
 	struct grid_cell	 gc;
 
@@ -926,21 +934,21 @@ screen_write_clearline(struct screen_write_ctx *ctx, u_int bg)
 {
 	struct screen			 *s = ctx->s;
 	struct grid_line		 *gl;
-	struct tty_ctx		 ttyctx;
 	u_int				  sx = screen_size_x(s);
+	struct screen_write_collect_item *ci = ctx->item;
 
 	gl = grid_get_line(s->grid, s->grid->hsize + s->cy);
 	if (gl->cellsize == 0 && COLOUR_DEFAULT(bg))
 		return;
 
-	screen_write_initctx(ctx, &ttyctx, 1);
-	ttyctx.bg = bg;
-
 	grid_view_clear(s->grid, 0, s->cy, sx, 1, bg);
 
 	screen_write_collect_clear(ctx, s->cy, 1);
-	screen_write_collect_flush(ctx, 0, __func__);
-	tty_write(tty_cmd_clearline, &ttyctx);
+	ci->x = 0;
+	ci->type = CLEAR;
+	ci->bg = bg;
+	TAILQ_INSERT_TAIL(&ctx->list[s->cy].items, ci, entry);
+	ctx->item = xcalloc(1, sizeof *ctx->item);
 }
 
 /* Clear to end of line from cursor. */
@@ -951,6 +959,12 @@ screen_write_clearendofline(struct screen_write_ctx *ctx, u_int bg)
 	struct grid_line		 *gl;
 	struct tty_ctx			  ttyctx;
 	u_int				  sx = screen_size_x(s);
+	struct screen_write_collect_item *ci = ctx->item;
+
+	if (s->cx == 0) {
+		screen_write_clearline(ctx, bg);
+		return;
+	}
 
 	gl = grid_get_line(s->grid, s->grid->hsize + s->cy);
 	if (s->cx > sx - 1 || (s->cx >= gl->cellsize && COLOUR_DEFAULT(bg)))
@@ -961,10 +975,13 @@ screen_write_clearendofline(struct screen_write_ctx *ctx, u_int bg)
 
 	grid_view_clear(s->grid, s->cx, s->cy, sx - s->cx, 1, bg);
 
-	if (s->cx == 0)
-		screen_write_collect_clear(ctx, s->cy, 1);
-	screen_write_collect_flush(ctx, 0, __func__);
-	tty_write(tty_cmd_clearendofline, &ttyctx);
+	if (!screen_write_collect_clear_end(ctx, s->cy, s->cx, bg)) {
+		ci->x = s->cx;
+		ci->type = CLEAR_END;
+		ci->bg = bg;
+		TAILQ_INSERT_TAIL(&ctx->list[s->cy].items, ci, entry);
+		ctx->item = xcalloc(1, sizeof *ctx->item);
+	}
 }
 
 /* Clear to start of line from cursor. */
@@ -974,6 +991,12 @@ screen_write_clearstartofline(struct screen_write_ctx *ctx, u_int bg)
 	struct screen			 *s = ctx->s;
 	struct tty_ctx			  ttyctx;
 	u_int				  sx = screen_size_x(s);
+	struct screen_write_collect_item *ci = ctx->item;
+
+	if (s->cx >= sx - 1) {
+		screen_write_clearline(ctx, bg);
+		return;
+	}
 
 	screen_write_initctx(ctx, &ttyctx, 1);
 	ttyctx.bg = bg;
@@ -983,10 +1006,13 @@ screen_write_clearstartofline(struct screen_write_ctx *ctx, u_int bg)
 	else
 		grid_view_clear(s->grid, 0, s->cy, s->cx + 1, 1, bg);
 
-	if (s->cx > sx - 1)
-		screen_write_collect_clear(ctx, s->cy, 1);
-	screen_write_collect_flush(ctx, 0, __func__);
-	tty_write(tty_cmd_clearstartofline, &ttyctx);
+	if (!screen_write_collect_clear_start(ctx, s->cy, s->cx, bg)) {
+		ci->x = s->cx;
+		ci->type = CLEAR_START;
+		ci->bg = bg;
+		TAILQ_INSERT_TAIL(&ctx->list[s->cy].items, ci, entry);
+		ctx->item = xcalloc(1, sizeof *ctx->item);
+	}
 }
 
 /* Move cursor to px,py. */
@@ -1018,16 +1044,17 @@ screen_write_reverseindex(struct screen_write_ctx *ctx, u_int bg)
 	struct screen	*s = ctx->s;
 	struct tty_ctx	 ttyctx;
 
+	if (s->cy == s->rupper) {
+		grid_view_scroll_region_down(s->grid, s->rupper, s->rlower, bg);
+		screen_write_collect_flush(ctx, 0, __func__);
+
 		screen_write_initctx(ctx, &ttyctx, 1);
 		ttyctx.bg = bg;
 
-	if (s->cy == s->rupper)
-		grid_view_scroll_region_down(s->grid, s->rupper, s->rlower, bg);
-	else if (s->cy > 0)
+		tty_write(tty_cmd_reverseindex, &ttyctx);
+	} else if (s->cy > 0)
 		screen_write_set_cursor(ctx, -1, s->cy - 1);
 
-	screen_write_collect_flush(ctx, 0, __func__);
-	tty_write(tty_cmd_reverseindex, &ttyctx);
 }
 
 /* Set scroll region. */
@@ -1217,25 +1244,114 @@ screen_write_clearhistory(struct screen_write_ctx *ctx)
 	grid_clear_history(ctx->s->grid);
 }
 
-/* Clear a collected line. */
+/* Clear to start of a collected line. */
+static int
+screen_write_collect_clear_start(struct screen_write_ctx *ctx, u_int y, u_int x,
+    u_int bg)
+{
+	struct screen_write_collect_item	*ci, *tmp;
+	size_t					 size = 0;
+	u_int					 items = 0;
+	int					 redundant = 0;
+
+	if (TAILQ_EMPTY(&ctx->list[y].items))
+		return (0);
+	TAILQ_FOREACH_SAFE(ci, &ctx->list[y].items, entry, tmp) {
+		switch (ci->type) {
+		case CLEAR:
+			continue;
+		case CLEAR_START:
+			if (ci->x >= x) {
+				if (ci->bg == bg)
+					redundant = 1;
+				continue;
+			}
+			break;
+		case CLEAR_END:
+			if (ci->x <= x)
+				ci->x = x;
+			continue;
+		case TEXT:
+			if (ci->x > x)
+				continue;
+			break;
+		}
+		items++;
+		size += ci->used;
+		TAILQ_REMOVE(&ctx->list[y].items, ci, entry);
+		free(ci);
+	}
+	ctx->skipped += size;
+	log_debug("%s: dropped %u items (%zu bytes) (line %u)", __func__, items,
+	    size, y);
+	return (redundant);
+}
+
+/* Clear to end of a collected line. */
+static int
+screen_write_collect_clear_end(struct screen_write_ctx *ctx, u_int y, u_int x,
+    u_int bg)
+{
+	struct screen_write_collect_item	*ci, *tmp;
+	size_t					 size = 0;
+	int					 redundant = 0;
+	u_int					 items = 0;
+
+	if (TAILQ_EMPTY(&ctx->list[y].items))
+		return (0);
+	TAILQ_FOREACH_SAFE(ci, &ctx->list[y].items, entry, tmp) {
+		switch (ci->type) {
+		case CLEAR:
+			continue;
+		case CLEAR_START:
+			if (ci->x >= x)
+				ci->x = x;
+			continue;
+		case CLEAR_END:
+			if (ci->x <= x) {
+				if (ci->bg == bg)
+					redundant = 1;
+				continue;
+			}
+			break;
+		case TEXT:
+			if (ci->x < x)
+				continue;
+			break;
+		}
+		items++;
+		size += ci->used;
+		TAILQ_REMOVE(&ctx->list[y].items, ci, entry);
+		free(ci);
+	}
+	ctx->skipped += size;
+	log_debug("%s: dropped %u items (%zu bytes) (line %u)", __func__, items,
+	    size, y);
+	return (redundant);
+}
+
+/* Clear part of a collected line. */
 static void
 screen_write_collect_clear(struct screen_write_ctx *ctx, u_int y, u_int n)
 {
 	struct screen_write_collect_item	*ci, *tmp;
-	u_int					 i;
+	u_int					 i, items;
 	size_t					 size;
 
 	for (i = y; i < y + n; i++) {
 		if (TAILQ_EMPTY(&ctx->list[i].items))
 			continue;
+		items = 0;
 		size = 0;
 		TAILQ_FOREACH_SAFE(ci, &ctx->list[i].items, entry, tmp) {
+			items++;
 			size += ci->used;
 			TAILQ_REMOVE(&ctx->list[i].items, ci, entry);
 			free(ci);
 		}
 		ctx->skipped += size;
-		log_debug("%s: dropped %zu bytes (line %u)", __func__, size, i);
+		log_debug("%s: dropped %u items (%zu bytes) (line %u)",
+		    __func__, items, size, y);
 	}
 }
 
@@ -1290,11 +1406,22 @@ screen_write_collect_flush(struct screen_write_ctx *ctx, int scroll_only,
 		TAILQ_FOREACH_SAFE(ci, &ctx->list[y].items, entry, tmp) {
 			screen_write_set_cursor(ctx, ci->x, y);
 			screen_write_initctx(ctx, &ttyctx, 0);
+			if (ci->type == CLEAR) {
+				ttyctx.bg = ci->bg;
+				tty_write(tty_cmd_clearline, &ttyctx);
+			} else if (ci->type == CLEAR_END) {
+				ttyctx.bg = ci->bg;
+				tty_write(tty_cmd_clearendofline, &ttyctx);
+			} else if (ci->type == CLEAR_START) {
+				ttyctx.bg = ci->bg;
+				tty_write(tty_cmd_clearstartofline, &ttyctx);
+			} else {
 				ttyctx.cell = &ci->gc;
 				ttyctx.wrapped = ci->wrapped;
 				ttyctx.ptr = ci->data;
 				ttyctx.num = ci->used;
 				tty_write(tty_cmd_cells, &ttyctx);
+			}
 
 			items++;
 			written += ci->used;