[PATCH wayland] client: Don't cancel a roundtrip when any event is received

[Jonas Ådahl]

Since wl_display_dispatch() returns the number of processed events or -1
on error, only cancel the roundtrip if an -1 is returned.

This also fixes a potential memory corruption bug happening when
wl_display_roundtrip() does an early return and the callback later
writes to the then out of scope stack allocated `done' parameter.

Introduced by 33b7637b4500a682018b503837b8aca9afae36f2.

Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
---
 src/wayland-client.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/wayland-client.c b/src/wayland-client.c
index 5fecc01..5ba2c45 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -649,9 +649,12 @@ wl_display_roundtrip(struct wl_display *display)
 	done = 0;
 	callback = wl_display_sync(display);
 	wl_callback_add_listener(callback, &sync_listener, &done);
-	while (!done && !ret)
+	while (!done && ret >= 0)
 		ret = wl_display_dispatch(display);
 
+	if (ret == -1 && !done)
+		wl_callback_destroy(callback);
+
 	return ret;
 }
 
-- 
1.7.10.4