From 217bbc3e940ee8886fc851ec46a90439e6c96431 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Wed, 22 Jan 2020 09:21:10 +0200
Subject: [PATCH] bus: Take the mutex before popping messages for the bus
 stream

Otherwise a message might arrive between popping, getting None and
locking the mutex for storing the waker. In that case we would never
be woken up.
---
 gstreamer/src/bus.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gstreamer/src/bus.rs b/gstreamer/src/bus.rs
index c5db1f30e..14bd54db7 100644
--- a/gstreamer/src/bus.rs
+++ b/gstreamer/src/bus.rs
@@ -269,11 +269,11 @@ impl Stream for BusStream {
     fn poll_next(self: Pin<&mut Self>, ctx: &mut Context) -> Poll<Option<Self::Item>> {
         let BusStream(ref bus, ref waker) = *self;
 
+        let mut waker = waker.lock().unwrap();
         let msg = bus.pop();
         if let Some(msg) = msg {
             Poll::Ready(Some(msg))
         } else {
-            let mut waker = waker.lock().unwrap();
             *waker = Some(ctx.waker().clone());
             Poll::Pending
         }