Allow retrieving the queue signal in a sink when using crossbeam-channel feature

src/conversions/sample.rs

@@ -67,7 +67,7 @@ where
 /// - For `u16`, silence corresponds to the value `u16::max_value() / 2`. The minimum and maximum
 ///   amplitudes are represented by `0` and `u16::max_value()` respectively.
 /// - For `f32`, silence corresponds to the value `0.0`. The minimum and maximum amplitudes are
-///  represented by `-1.0` and `1.0` respectively.
+///   represented by `-1.0` and `1.0` respectively.
 ///
 /// You can implement this trait on your own type as well if you wish so.
 ///

src/sink.rs

@@ -102,6 +102,19 @@ impl Sink {
     /// Appends a sound to the queue of sounds to play.
     #[inline]
     pub fn append<S>(&self, source: S)
+    where
+        S: Source + Send + 'static,
+        f32: FromSample<S::Item>,
+        S::Item: Sample + Send,
+    {
+        self.append_with_signal(source);
+    }
+
+    /// Appends a sound to the queue of sounds to play
+    ///
+    /// When using the feature flag `crossbeam-channel` in rodio the `crossbeam_channel::Receiver` will be returned when the sound has finished playing.
+    #[inline]
+    pub fn append_with_signal<S>(&self, source: S) -> Option<Receiver<()>>
     where
         S: Source + Send + 'static,
         f32: FromSample<S::Item>,
@@ -159,7 +172,19 @@ impl Sink {
             .convert_samples();
         self.sound_count.fetch_add(1, Ordering::Relaxed);
         let source = Done::new(source, self.sound_count.clone());
-        *self.sleep_until_end.lock().unwrap() = Some(self.queue_tx.append_with_signal(source));
+        let rx = self.queue_tx.append_with_signal(source);
+
+        #[cfg(not(feature = "crossbeam-channel"))]
+        {
+            *self.sleep_until_end.lock().unwrap() = Some(rx);
+            None
+        }
+
+        #[cfg(feature = "crossbeam-channel")]
+        {
+            *self.sleep_until_end.lock().unwrap() = Some(rx.clone());
+            Some(rx)
+        }
     }
 
     /// Gets the volume of the sound.