Merge pull request #370 from orottier/bugfix/369

Fix #369 - AudioListener would have a connection to a dropped PannerNode

Author: orottier

src/render/graph.rs

@@ -453,12 +453,16 @@ impl Graph {
                 // Nodes are only dropped when they do not have incoming connections.
                 // But they may have AudioParams feeding into them, these can de dropped too.
                 nodes.retain(|id, n| {
-                    id.0 < 2 // never drop Listener and Destination node
-                        || !n
-                            .borrow()
-                            .outgoing_edges
-                            .iter()
-                            .any(|e| e.other_id == *index)
+                    // Check if this node was connected to the dropped node. In that case, it is
+                    // either an AudioParam (which can be dropped), or the AudioListener that feeds
+                    // into a PannerNode (which can be disconnected).
+                    let outgoing_edges = &mut n.borrow_mut().outgoing_edges;
+                    let prev_len = outgoing_edges.len();
+                    outgoing_edges.retain(|e| e.other_id != *index);
+                    let was_connected = outgoing_edges.len() != prev_len;
+
+                    let special = id.0 < 2; // never drop Listener and Destination node
+                    special || !was_connected
                 });
             }
         });

tests/online.rs

@@ -121,3 +121,30 @@ fn test_channels() {
     context.destination().set_channel_count(5);
     assert_eq!(context.destination().channel_count(), 5);
 }
+
+#[test]
+fn test_panner_node_drop_panic() {
+    // https://github.com/orottier/web-audio-api-rs/issues/369
+    let options = AudioContextOptions {
+        sink_id: "none".into(),
+        ..AudioContextOptions::default()
+    };
+    let context = AudioContext::new(options);
+
+    // create a new panner and drop it
+    let panner = context.create_panner();
+    drop(panner);
+
+    // allow the audio render thread to boot and handle adding and dropping the panner
+    std::thread::sleep(std::time::Duration::from_millis(200));
+
+    // creating a new panner node should not crash the render thread
+    let mut _panner = context.create_panner();
+
+    // A crashed thread will not fail the test (only if the main thread panics).
+    // Instead inspect if there is progression of time in the audio context.
+
+    let time = context.current_time();
+    std::thread::sleep(std::time::Duration::from_millis(200));
+    assert!(context.current_time() >= time + 0.15);
+}