[PATCH xwayland] xwayland: Just send the bounding box of the damage

[Adam Jackson]

... instead of every rect.  Most window updates are going to be CopyArea
in from offscreen, with plenty of time to get back around to
BlockHandler in between, so this is no change there.  However for
pathological apps like x11perf that draw complicated primitives directly
to the window you can end up with massive numbers of damage rects, and
you can run out of space in the write buffer and crash.

This obviously isn't a complete fix, and it would be nice to handle this
more gracefully in the wayland client code, but this at least lets
x11perf -all run to completion.

While we're in the area, rearrange attach to be before damage, not
after, since the spec says that's the correct order.

Signed-off-by: Adam Jackson <ajax at redhat.com>
---
 hw/xfree86/xwayland/xwayland.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/hw/xfree86/xwayland/xwayland.c b/hw/xfree86/xwayland/xwayland.c
index c70a52d..c10a213 100644
--- a/hw/xfree86/xwayland/xwayland.c
+++ b/hw/xfree86/xwayland/xwayland.c
@@ -333,22 +333,18 @@ void xwl_screen_post_damage(struct xwl_screen *xwl_screen)
     struct xwl_window *xwl_window;
     RegionPtr region;
     BoxPtr box;
-    int count, i;
 
     xorg_list_for_each_entry(xwl_window, &xwl_screen->damage_window_list,
 			     link_damage) {
 	region = DamageRegion(xwl_window->damage);
-	count = RegionNumRects(region);
-	for (i = 0; i < count; i++) {
-	    box = &RegionRects(region)[i];
-	    wl_surface_damage(xwl_window->surface,
-			      box->x1, box->y1,
-			      box->x2 - box->x1,
-			      box->y2 - box->y1);
-	}
 	wl_surface_attach(xwl_window->surface,
 			  xwl_window->buffer,
 			  0, 0);
+	box = &region->extents;
+	wl_surface_damage(xwl_window->surface,
+			  box->x1, box->y1,
+			  box->x2 - box->x1,
+			  box->y2 - box->y1);
 	wl_surface_commit(xwl_window->surface);
 	DamageEmpty(xwl_window->damage);
     }
-- 
1.8.3.1