screen: implement trivial ageing

To fully support the new ageing API, we now implement trivial ageing. On
each modification, we simply increase the screen-age (which overwrites any
line or cell age). This basically invalidates the whole screen on each
change, but at least makes the ageing API work.

Note that for cursor movements we actually age only both changed cells.
Same for flag-changes. But these are the only non-trivial ageing
implementations so far.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

1 files changed, 226 insertions, 31 deletions

diff --git a/src/tsm_screen.c b/src/tsm_screen.c
index 18d877e..5a48b78 100644
--- a/src/tsm_screen.c
+++ b/src/tsm_screen.c
@@ -138,6 +138,46 @@ struct tsm_screen {
 	struct selection_pos sel_end;
 };
 
+static void inc_age(struct tsm_screen *con)
+{
+	if (!++con->age_cnt) {
+		con->age_reset = 1;
+		++con->age_cnt;
+	}
+}
+
+static struct cell *get_cursor_cell(struct tsm_screen *con)
+{
+	unsigned int cur_x, cur_y;
+
+	cur_x = con->cursor_x;
+	if (cur_x >= con->size_x)
+		cur_x = con->size_x - 1;
+
+	cur_y = con->cursor_y;
+	if (cur_y >= con->size_y)
+		cur_y = con->size_y - 1;
+
+	return &con->lines[cur_y]->cells[cur_x];
+}
+
+static void move_cursor(struct tsm_screen *con, unsigned int x, unsigned int y)
+{
+	struct cell *c;
+
+	if (con->cursor_x == x && con->cursor_y == y)
+		return;
+
+	c = get_cursor_cell(con);
+	c->age = con->age_cnt;
+
+	con->cursor_x = x;
+	con->cursor_y = y;
+
+	c = get_cursor_cell(con);
+	c->age = con->age_cnt;
+}
+
 static void cell_init(struct tsm_screen *con, struct cell *cell)
 {
 	cell->ch = 0;
@@ -211,6 +251,9 @@ static void link_to_scrollback(struct tsm_screen *con, struct line *line)
 {
 	struct line *tmp;
 
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	if (con->sb_max == 0) {
 		if (con->sel_active) {
 			if (con->sel_start.line == line) {
@@ -288,6 +331,9 @@ static void screen_scroll_up(struct tsm_screen *con, unsigned int num)
 	if (!num)
 		return;
 
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	max = con->margin_bottom + 1 - con->margin_top;
 	if (num > max)
 		num = max;
@@ -357,6 +403,9 @@ static void screen_scroll_down(struct tsm_screen *con, unsigned int num)
 	if (!num)
 		return;
 
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	max = con->margin_bottom + 1 - con->margin_top;
 	if (num > max)
 		num = max;
@@ -406,6 +455,9 @@ static void screen_write(struct tsm_screen *con, unsigned int x,
 		return;
 	}
 
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	line = con->lines[y];
 
 	if ((con->flags & TSM_SCREEN_INSERT_MODE) &&
@@ -431,6 +483,9 @@ static void screen_erase_region(struct tsm_screen *con,
 	unsigned int to;
 	struct line *line;
 
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	if (y_to >= con->size_y)
 		y_to = con->size_y - 1;
 	if (x_to >= con->size_x)
@@ -676,6 +731,10 @@ int tsm_screen_resize(struct tsm_screen *con, unsigned int x,
 		}
 	}
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	/* clear expansion/padding area */
 	for (j = 0; j < con->line_num; ++j) {
 		i = 0;
@@ -773,6 +832,10 @@ void tsm_screen_set_max_sb(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	while (con->sb_count > max) {
 		line = con->sb_first;
 		con->sb_first = line->next;
@@ -812,6 +875,10 @@ void tsm_screen_clear_sb(struct tsm_screen *con)
 	if (!con)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	for (iter = con->sb_first; iter; ) {
 		tmp = iter;
 		iter = iter->next;
@@ -841,6 +908,10 @@ void tsm_screen_sb_up(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	while (num--) {
 		if (con->sb_pos) {
 			if (!con->sb_pos->prev)
@@ -861,6 +932,10 @@ void tsm_screen_sb_down(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	while (num--) {
 		if (con->sb_pos)
 			con->sb_pos = con->sb_pos->next;
@@ -875,6 +950,7 @@ void tsm_screen_sb_page_up(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
 	tsm_screen_sb_up(con, num * con->size_y);
 }
 
@@ -884,6 +960,7 @@ void tsm_screen_sb_page_down(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
 	tsm_screen_sb_down(con, num * con->size_y);
 }
 
@@ -893,6 +970,10 @@ void tsm_screen_sb_reset(struct tsm_screen *con)
 	if (!con)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	con->sb_pos = NULL;
 }
 
@@ -914,6 +995,9 @@ void tsm_screen_reset(struct tsm_screen *con)
 	if (!con)
 		return;
 
+	inc_age(con);
+	con->age = con->age_cnt;
+
 	con->flags = 0;
 	con->margin_top = 0;
 	con->margin_bottom = con->size_y - 1;
@@ -931,30 +1015,58 @@ SHL_EXPORT
 void tsm_screen_set_flags(struct tsm_screen *con, unsigned int flags)
 {
 	unsigned int old;
+	struct cell *c;
 
 	if (!con || !flags)
 		return;
 
+	inc_age(con);
+
 	old = con->flags;
 	con->flags |= flags;
 
-	if (!(old & TSM_SCREEN_ALTERNATE) && (flags & TSM_SCREEN_ALTERNATE))
+	if (!(old & TSM_SCREEN_ALTERNATE) && (flags & TSM_SCREEN_ALTERNATE)) {
+		con->age = con->age_cnt;
 		con->lines = con->alt_lines;
+	}
+
+	if (!(old & TSM_SCREEN_HIDE_CURSOR) &&
+	    (flags & TSM_SCREEN_HIDE_CURSOR)) {
+		c = get_cursor_cell(con);
+		c->age = con->age_cnt;
+	}
+
+	if (!(old & TSM_SCREEN_INVERSE) && (flags & TSM_SCREEN_INVERSE))
+		con->age = con->age_cnt;
 }
 
 SHL_EXPORT
 void tsm_screen_reset_flags(struct tsm_screen *con, unsigned int flags)
 {
 	unsigned int old;
+	struct cell *c;
 
 	if (!con || !flags)
 		return;
 
+	inc_age(con);
+
 	old = con->flags;
 	con->flags &= ~flags;
 
-	if ((old & TSM_SCREEN_ALTERNATE) && (flags & TSM_SCREEN_ALTERNATE))
+	if ((old & TSM_SCREEN_ALTERNATE) && (flags & TSM_SCREEN_ALTERNATE)) {
+		con->age = con->age_cnt;
 		con->lines = con->main_lines;
+	}
+
+	if ((old & TSM_SCREEN_HIDE_CURSOR) &&
+	    (flags & TSM_SCREEN_HIDE_CURSOR)) {
+		c = get_cursor_cell(con);
+		c->age = con->age_cnt;
+	}
+
+	if ((old & TSM_SCREEN_INVERSE) && (flags & TSM_SCREEN_INVERSE))
+		con->age = con->age_cnt;
 }
 
 SHL_EXPORT
@@ -1027,6 +1139,10 @@ void tsm_screen_write(struct tsm_screen *con, tsm_symbol_t ch,
 	if (!len)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	if (con->cursor_y <= con->margin_bottom ||
 	    con->cursor_y >= con->size_y)
 		last = con->margin_bottom;
@@ -1057,6 +1173,8 @@ void tsm_screen_newline(struct tsm_screen *con)
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	tsm_screen_move_down(con, 1, true);
 	tsm_screen_move_line_home(con);
 }
@@ -1067,6 +1185,8 @@ void tsm_screen_scroll_up(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	screen_scroll_up(con, num);
 }
 
@@ -1076,6 +1196,8 @@ void tsm_screen_scroll_down(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	screen_scroll_down(con, num);
 }
 
@@ -1088,18 +1210,22 @@ void tsm_screen_move_to(struct tsm_screen *con, unsigned int x,
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	if (con->flags & TSM_SCREEN_REL_ORIGIN)
 		last = con->margin_bottom;
 	else
 		last = con->size_y - 1;
 
-	con->cursor_x = to_abs_x(con, x);
-	if (con->cursor_x >= con->size_x)
-		con->cursor_x = con->size_x - 1;
+	x = to_abs_x(con, x);
+	if (x >= con->size_x)
+		x = con->size_x - 1;
 
-	con->cursor_y = to_abs_y(con, y);
-	if (con->cursor_y > last)
-		con->cursor_y = last;
+	y = to_abs_y(con, y);
+	if (y > last)
+		y = last;
+
+	move_cursor(con, x, y);
 }
 
 SHL_EXPORT
@@ -1111,6 +1237,8 @@ void tsm_screen_move_up(struct tsm_screen *con, unsigned int num,
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	if (con->cursor_y >= con->margin_top)
 		size = con->margin_top;
 	else
@@ -1121,9 +1249,9 @@ void tsm_screen_move_up(struct tsm_screen *con, unsigned int num,
 		num -= diff;
 		if (scroll)
 			screen_scroll_down(con, num);
-		con->cursor_y = size;
+		move_cursor(con, con->cursor_x, size);
 	} else {
-		con->cursor_y -= num;
+		move_cursor(con, con->cursor_x, con->cursor_y - num);
 	}
 }
 
@@ -1136,6 +1264,8 @@ void tsm_screen_move_down(struct tsm_screen *con, unsigned int num,
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	if (con->cursor_y <= con->margin_bottom)
 		size = con->margin_bottom + 1;
 	else
@@ -1146,28 +1276,33 @@ void tsm_screen_move_down(struct tsm_screen *con, unsigned int num,
 		num -= diff;
 		if (scroll)
 			screen_scroll_up(con, num);
-		con->cursor_y = size - 1;
+		move_cursor(con, con->cursor_x, size - 1);
 	} else {
-		con->cursor_y += num;
+		move_cursor(con, con->cursor_x, con->cursor_y + num);
 	}
 }
 
 SHL_EXPORT
 void tsm_screen_move_left(struct tsm_screen *con, unsigned int num)
 {
+	unsigned int x;
+
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	if (num > con->size_x)
 		num = con->size_x;
 
-	if (con->cursor_x >= con->size_x)
-		con->cursor_x = con->size_x - 1;
+	x = con->cursor_x;
+	if (x >= con->size_x)
+		x = con->size_x - 1;
 
-	if (num > con->cursor_x)
-		con->cursor_x = 0;
+	if (num > x)
+		move_cursor(con, 0, con->cursor_y);
 	else
-		con->cursor_x -= num;
+		move_cursor(con, x - num, con->cursor_y);
 }
 
 SHL_EXPORT
@@ -1176,13 +1311,15 @@ void tsm_screen_move_right(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	if (num > con->size_x)
 		num = con->size_x;
 
 	if (num + con->cursor_x >= con->size_x)
-		con->cursor_x = con->size_x - 1;
+		move_cursor(con, con->size_x - 1, con->cursor_y);
 	else
-		con->cursor_x += num;
+		move_cursor(con, con->cursor_x + num, con->cursor_y);
 }
 
 SHL_EXPORT
@@ -1191,7 +1328,9 @@ void tsm_screen_move_line_end(struct tsm_screen *con)
 	if (!con)
 		return;
 
-	con->cursor_x = con->size_x - 1;
+	inc_age(con);
+
+	move_cursor(con, con->size_x - 1, con->cursor_y);
 }
 
 SHL_EXPORT
@@ -1200,54 +1339,66 @@ void tsm_screen_move_line_home(struct tsm_screen *con)
 	if (!con)
 		return;
 
-	con->cursor_x = 0;
+	inc_age(con);
+
+	move_cursor(con, 0, con->cursor_y);
 }
 
 SHL_EXPORT
 void tsm_screen_tab_right(struct tsm_screen *con, unsigned int num)
 {
-	unsigned int i, j;
+	unsigned int i, j, x;
 
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
+	x = con->cursor_x;
 	for (i = 0; i < num; ++i) {
-		for (j = con->cursor_x + 1; j < con->size_x; ++j) {
+		for (j = x + 1; j < con->size_x; ++j) {
 			if (con->tab_ruler[j])
 				break;
 		}
 
-		con->cursor_x = j;
-		if (con->cursor_x + 1 >= con->size_x)
+		x = j;
+		if (x + 1 >= con->size_x)
 			break;
 	}
 
 	/* tabs never cause pending new-lines */
-	if (con->cursor_x >= con->size_x)
-		con->cursor_x = con->size_x - 1;
+	if (x >= con->size_x)
+		x = con->size_x - 1;
+
+	move_cursor(con, x, con->cursor_y);
 }
 
 SHL_EXPORT
 void tsm_screen_tab_left(struct tsm_screen *con, unsigned int num)
 {
-	unsigned int i;
+	unsigned int i, x;
 	int j;
 
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
+	x = con->cursor_x;
 	for (i = 0; i < num; ++i) {
-		for (j = con->cursor_x - 1; j > 0; --j) {
+		for (j = x - 1; j > 0; --j) {
 			if (con->tab_ruler[j])
 				break;
 		}
 
 		if (j <= 0) {
-			con->cursor_x = 0;
+			x = 0;
 			break;
 		}
-		con->cursor_x = j;
+		x = j;
 	}
+
+	move_cursor(con, x, con->cursor_y);
 }
 
 SHL_EXPORT
@@ -1262,6 +1413,10 @@ void tsm_screen_insert_lines(struct tsm_screen *con, unsigned int num)
 	    con->cursor_y > con->margin_bottom)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	max = con->margin_bottom - con->cursor_y + 1;
 	if (num > max)
 		num = max;
@@ -1298,6 +1453,10 @@ void tsm_screen_delete_lines(struct tsm_screen *con, unsigned int num)
 	    con->cursor_y > con->margin_bottom)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	max = con->margin_bottom - con->cursor_y + 1;
 	if (num > max)
 		num = max;
@@ -1331,6 +1490,10 @@ void tsm_screen_insert_chars(struct tsm_screen *con, unsigned int num)
 	if (!con || !num || !con->size_y || !con->size_x)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	if (con->cursor_x >= con->size_x)
 		con->cursor_x = con->size_x - 1;
 	if (con->cursor_y >= con->size_y)
@@ -1360,6 +1523,10 @@ void tsm_screen_delete_chars(struct tsm_screen *con, unsigned int num)
 	if (!con || !num || !con->size_y || !con->size_x)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	if (con->cursor_x >= con->size_x)
 		con->cursor_x = con->size_x - 1;
 	if (con->cursor_y >= con->size_y)
@@ -1388,6 +1555,8 @@ void tsm_screen_erase_cursor(struct tsm_screen *con)
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	if (con->cursor_x >= con->size_x)
 		x = con->size_x - 1;
 	else
@@ -1404,6 +1573,8 @@ void tsm_screen_erase_chars(struct tsm_screen *con, unsigned int num)
 	if (!con || !num)
 		return;
 
+	inc_age(con);
+
 	if (con->cursor_x >= con->size_x)
 		x = con->size_x - 1;
 	else
@@ -1422,6 +1593,8 @@ void tsm_screen_erase_cursor_to_end(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	if (con->cursor_x >= con->size_x)
 		x = con->size_x - 1;
 	else
@@ -1438,6 +1611,8 @@ void tsm_screen_erase_home_to_cursor(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	screen_erase_region(con, 0, con->cursor_y, con->cursor_x,
 			     con->cursor_y, protect);
 }
@@ -1449,6 +1624,8 @@ void tsm_screen_erase_current_line(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	screen_erase_region(con, 0, con->cursor_y, con->size_x - 1,
 			     con->cursor_y, protect);
 }
@@ -1460,6 +1637,8 @@ void tsm_screen_erase_screen_to_cursor(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	screen_erase_region(con, 0, 0, con->cursor_x, con->cursor_y, protect);
 }
 
@@ -1472,6 +1651,8 @@ void tsm_screen_erase_cursor_to_screen(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	if (con->cursor_x >= con->size_x)
 		x = con->size_x - 1;
 	else
@@ -1487,6 +1668,8 @@ void tsm_screen_erase_screen(struct tsm_screen *con, bool protect)
 	if (!con)
 		return;
 
+	inc_age(con);
+
 	screen_erase_region(con, 0, 0, con->size_x - 1, con->size_y - 1,
 			     protect);
 }
@@ -1544,6 +1727,10 @@ void tsm_screen_selection_reset(struct tsm_screen *con)
 	if (!con)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	con->sel_active = false;
 }
 
@@ -1555,6 +1742,10 @@ void tsm_screen_selection_start(struct tsm_screen *con,
 	if (!con)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	con->sel_active = true;
 	selection_set(con, &con->sel_start, posx, posy);
 	memcpy(&con->sel_end, &con->sel_start, sizeof(con->sel_end));
@@ -1568,6 +1759,10 @@ void tsm_screen_selection_target(struct tsm_screen *con,
 	if (!con || !con->sel_active)
 		return;
 
+	inc_age(con);
+	/* TODO: more sophisticated ageing */
+	con->age = con->age_cnt;
+
 	selection_set(con, &con->sel_end, posx, posy);
 }