[PATCH weston 3/5] compositor: Fix crash when surface is map'd and unmap'd before repaint

[Ander Conselvan de Oliveira]

---
For the record, I ran into this issue while doing the cursor surfaces
patches, but I could also reproduce it with this patch. I looked into
writing this as test but it wasn't obvious to me how I would do that
with the current test framework, so I just gave up.


 clients/simple-shm.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/clients/simple-shm.c b/clients/simple-shm.c
index 252e040..dc966a3 100644
--- a/clients/simple-shm.c
+++ b/clients/simple-shm.c
@@ -201,18 +201,29 @@ paint_pixels(void *image, int width, int height, uint32_t time)
 	}
 }
 
+static int needs_remap;
+static uint32_t last_time;
+
 static const struct wl_callback_listener frame_listener;
 
 static void
 redraw(void *data, struct wl_callback *callback, uint32_t time)
 {
 	struct window *window = data;
+	static int count;
+
+	last_time = time;
 
 	paint_pixels(window->shm_data, window->width, window->height, time);
 	wl_surface_attach(window->surface, window->buffer, 0, 0);
 	wl_surface_damage(window->surface,
 			  0, 0, window->width, window->height);
 
+	if (count++ % 20 == 19) {
+		wl_surface_attach(window->surface, NULL, 0, 0);
+		needs_remap = 1;
+	}
+
 	if (callback)
 		wl_callback_destroy(callback);
 
@@ -332,8 +343,13 @@ main(int argc, char **argv)
 
 	redraw(window, NULL, 0);
 
-	while (running)
+	while (running) {
+		if (needs_remap) {
+			redraw(window, NULL, last_time);
+			needs_remap = 0;
+		}
 		wl_display_iterate(display->display, display->mask);
+	}
 
 	fprintf(stderr, "simple-shm exiting\n");
 	destroy_window(window);
-- 
1.7.4.1