OfflineAudioContext should set state to suspended when suspending

Fixes #416

Author: orottier

src/context/offline.rs

@@ -135,7 +135,11 @@ impl OfflineAudioContext {
             ..
         } = renderer;
 
-        renderer.render_audiobuffer_sync(self.length, suspend_callbacks, self)
+        self.base.set_state(AudioContextState::Running);
+        let result = renderer.render_audiobuffer_sync(self.length, suspend_callbacks, self);
+        self.base.set_state(AudioContextState::Closed);
+
+        result
     }
 
     /// Given the current connections and scheduled changes, starts rendering audio.
@@ -163,9 +167,15 @@ impl OfflineAudioContext {
             ..
         } = renderer;
 
-        renderer
+        self.base.set_state(AudioContextState::Running);
+
+        let result = renderer
             .render_audiobuffer(self.length, suspend_promises, resume_receiver)
-            .await
+            .await;
+
+        self.base.set_state(AudioContextState::Closed);
+
+        result
     }
 
     /// get the length of rendering audio buffer
@@ -257,7 +267,8 @@ impl OfflineAudioContext {
                 .insert(insert_pos, (quantum, sender));
         } // lock is dropped
 
-        receiver.await.unwrap()
+        receiver.await.unwrap();
+        self.base().set_state(AudioContextState::Suspended);
     }
 
     /// Schedules a suspension of the time progression in the audio context at the specified time
@@ -317,9 +328,15 @@ impl OfflineAudioContext {
                 "InvalidStateError: cannot suspend multiple times at the same render quantum",
             );
 
+        let boxed_callback = Box::new(|ctx: &mut OfflineAudioContext| {
+            ctx.base().set_state(AudioContextState::Suspended);
+            (callback)(ctx);
+            ctx.base().set_state(AudioContextState::Running);
+        });
+
         renderer
             .suspend_callbacks
-            .insert(insert_pos, (quantum, Box::new(callback)));
+            .insert(insert_pos, (quantum, boxed_callback));
     }
 
     /// Resumes the progression of the OfflineAudioContext's currentTime when it has been suspended
@@ -328,6 +345,7 @@ impl OfflineAudioContext {
     ///
     /// Panics when the context is closed or rendering has not started
     pub async fn resume(&self) {
+        self.base().set_state(AudioContextState::Running);
         self.resume_sender.clone().send(()).await.unwrap()
     }
 }
@@ -343,6 +361,7 @@ mod tests {
     #[test]
     fn render_empty_graph() {
         let mut context = OfflineAudioContext::new(2, 555, 44_100.);
+        assert_eq!(context.state(), AudioContextState::Suspended);
         let buffer = context.start_rendering_sync();
 
         assert_eq!(context.length(), 555);
@@ -351,6 +370,8 @@ mod tests {
         assert_eq!(buffer.length(), 555);
         assert_float_eq!(buffer.get_channel_data(0), &[0.; 555][..], abs_all <= 0.);
         assert_float_eq!(buffer.get_channel_data(1), &[0.; 555][..], abs_all <= 0.);
+
+        assert_eq!(context.state(), AudioContextState::Closed);
     }
 
     #[test]
@@ -369,12 +390,14 @@ mod tests {
         let mut context = OfflineAudioContext::new(1, len, sample_rate as f32);
 
         context.suspend_sync(RENDER_QUANTUM_SIZE as f64 / sample_rate, |context| {
+            assert_eq!(context.state(), AudioContextState::Suspended);
             let mut src = context.create_constant_source();
             src.connect(&context.destination());
             src.start();
         });
 
         context.suspend_sync((3 * RENDER_QUANTUM_SIZE) as f64 / sample_rate, |context| {
+            assert_eq!(context.state(), AudioContextState::Suspended);
             context.destination().disconnect();
         });