Auto merge of #58 - paulrouget:shutdown, r=Manishearth

More shutdown event processing

This fixes 2 different crashes at shutdown.

The initial approach of checking if session was running, then call RAF would fail as we would call `is_running()` before processing the event.

I got rid of the `is_running()` mechanic and instead made `wait_for_animation_frame` return an Option. Assuming that returning None mean the session has ended.

Fix #47

webxr-api/device.rs

@@ -48,13 +48,9 @@ pub trait Device: 'static {
         Size2D::new(viewport.max_x(), viewport.max_y())
     }
 
-    /// This method checks if the session has exited since last
-    /// wait_for_animation_frame call.
-    fn is_running(&self) -> bool;
-
     /// This method should block waiting for the next frame,
     /// and return the information for it.
-    fn wait_for_animation_frame(&mut self) -> Frame;
+    fn wait_for_animation_frame(&mut self) -> Option<Frame>;
 
     /// This method should render a GL texture to the device.
     /// While this method is being called, the device has unique access

webxr-api/session.rs

@@ -205,12 +205,14 @@ impl<D: Device> SessionThread<D> {
             }
             SessionMsg::RequestAnimationFrame(dest) => {
                 let timestamp = self.timestamp;
-                if self.device.is_running() {
-                    let frame = self.device.wait_for_animation_frame();
-                    let _ = dest.send((timestamp, frame));
-                } else {
-                    return false;
-                }
+                match self.device.wait_for_animation_frame() {
+                    Some(frame) => {
+                        let _ = dest.send((timestamp, frame));
+                    }
+                    None => {
+                        return false;
+                    }
+                };
             }
             SessionMsg::UpdateClipPlanes(near, far) => self.device.update_clip_planes(near, far),
             SessionMsg::RenderAnimationFrame => {

webxr/glwindow/mod.rs

@@ -89,7 +89,6 @@ pub struct GlWindowDevice {
     read_fbo: GLuint,
     events: EventBuffer,
     clip_planes: ClipPlanes,
-    is_running: bool,
 }
 
 impl Device for GlWindowDevice {
@@ -104,7 +103,7 @@ impl Device for GlWindowDevice {
         Views::Stereo(left, right)
     }
 
-    fn wait_for_animation_frame(&mut self) -> Frame {
+    fn wait_for_animation_frame(&mut self) -> Option<Frame> {
         self.window.swap_buffers();
         let translation = Vector3D::new(0.0, 0.0, -5.0);
         let transform = RigidTransform3D::from_translation(translation);
@@ -113,11 +112,11 @@ impl Device for GlWindowDevice {
         } else {
             vec![]
         };
-        Frame {
+        Some(Frame {
             transform,
             inputs: vec![],
             events,
-        }
+        })
     }
 
     fn render_animation_frame(
@@ -178,12 +177,7 @@ impl Device for GlWindowDevice {
         self.events.upgrade(dest)
     }
 
-    fn is_running(&self) -> bool {
-        self.is_running
-    }
-
     fn quit(&mut self) {
-        self.is_running = false;
         self.events.callback(Event::SessionEnd);
     }
 
@@ -210,7 +204,6 @@ impl GlWindowDevice {
             read_fbo,
             events: Default::default(),
             clip_planes: Default::default(),
-            is_running: true,
         })
     }
 

webxr/googlevr/device.rs

@@ -63,7 +63,6 @@ pub(crate) struct GoogleVRDevice {
     depth: bool,
     clip_planes: ClipPlanes,
     input: Option<GoogleVRController>,
-    is_running: bool,
 
     #[cfg(target_os = "android")]
     java_class: ndk::jclass,
@@ -99,7 +98,6 @@ impl GoogleVRDevice {
             depth: false,
             clip_planes: Default::default(),
             input: None,
-            is_running: true,
 
             ctx: ctx.get(),
             controller_ctx: controller_ctx.get(),
@@ -141,7 +139,6 @@ impl GoogleVRDevice {
             depth: false,
             clip_planes: Default::default(),
             input: None,
-            is_running: true,
 
             ctx: ctx.get(),
             controller_ctx: controller_ctx.get(),
@@ -532,7 +529,7 @@ impl Device for GoogleVRDevice {
         }
     }
 
-    fn wait_for_animation_frame(&mut self) -> Frame {
+    fn wait_for_animation_frame(&mut self) -> Option<Frame> {
         unsafe {
             self.acquire_frame();
         }
@@ -542,11 +539,11 @@ impl Device for GoogleVRDevice {
             vec![]
         };
         // Predict head matrix
-        Frame {
+        Some(Frame {
             transform: self.fetch_head_matrix(),
             inputs: self.input_state(),
             events,
-        }
+        })
     }
 
     fn render_animation_frame(
@@ -582,14 +579,9 @@ impl Device for GoogleVRDevice {
         self.events.upgrade(dest);
     }
 
-    fn is_running(&self) -> bool {
-        self.is_running
-    }
-
     fn quit(&mut self) {
         self.stop_present();
         self.events.callback(Event::SessionEnd);
-        self.is_running = false;
     }
 
     fn set_quitter(&mut self, _: Quitter) {

webxr/headless/mod.rs

@@ -58,7 +58,6 @@ struct InputInfo {
 struct HeadlessDevice {
     gl: Rc<dyn Gl>,
     data: Arc<Mutex<HeadlessDeviceData>>,
-    is_running: bool,
 }
 
 struct HeadlessDeviceData {
@@ -120,13 +119,7 @@ impl Discovery for HeadlessDiscovery {
         }
         let gl = self.gl.clone();
         let data = self.data.clone();
-        xr.run_on_main_thread(move || {
-            Ok(HeadlessDevice {
-                gl,
-                data,
-                is_running: true,
-            })
-        })
+        xr.run_on_main_thread(move || Ok(HeadlessDevice { gl, data }))
     }
 
     fn supports_session(&self, mode: SessionMode) -> bool {
@@ -143,7 +136,7 @@ impl Device for HeadlessDevice {
         self.data.lock().unwrap().views.clone()
     }
 
-    fn wait_for_animation_frame(&mut self) -> Frame {
+    fn wait_for_animation_frame(&mut self) -> Option<Frame> {
         let mut data = self.data.lock().unwrap();
         let transform = data.viewer_origin;
         let inputs = data
@@ -162,11 +155,11 @@ impl Device for HeadlessDevice {
         } else {
             vec![]
         };
-        Frame {
+        Some(Frame {
             transform,
             inputs,
             events,
-        }
+        })
     }
 
     fn render_animation_frame(&mut self, _: GLuint, _: Size2D<i32>, sync: Option<GLsync>) {
@@ -184,12 +177,7 @@ impl Device for HeadlessDevice {
         self.data.lock().unwrap().events.upgrade(dest)
     }
 
-    fn is_running(&self) -> bool {
-        self.is_running
-    }
-
     fn quit(&mut self) {
-        self.is_running = false;
         self.data.lock().unwrap().events.callback(Event::SessionEnd);
     }
 

webxr/magicleap/mod.rs

@@ -98,7 +98,6 @@ pub struct MagicLeapDevice {
     frame_handle: MLHandle,
     cameras: MLGraphicsVirtualCameraInfoArray,
     view_update_needed: bool,
-    is_running: bool,
 }
 
 impl MagicLeapDiscovery {
@@ -165,7 +164,6 @@ impl MagicLeapDevice {
             frame_handle,
             cameras,
             view_update_needed: false,
-            is_running: true,
         };
 
         // Rather annoyingly, in order for the views to be available, we have to
@@ -444,12 +442,7 @@ impl Device for MagicLeapDevice {
         // TODO: handle events
     }
 
-    fn is_running(&self) -> bool {
-        self.is_running
-    }
-
     fn quit(&mut self) {
-        self.is_running = false;
         // TODO: handle quit
     }
 

webxr/openxr/mod.rs

@@ -122,7 +122,6 @@ struct OpenXrDevice {
     resource: ComPtr<dxgi::IDXGIResource>,
     device_context: ComPtr<d3d11::ID3D11DeviceContext>,
     device: ComPtr<d3d11::ID3D11Device>,
-    is_running: bool,
 }
 
 impl OpenXrDevice {
@@ -261,11 +260,10 @@ impl OpenXrDevice {
             resource,
             device_context,
             device,
-            is_running: true,
         })
     }
 
-    fn handle_openxr_events(&mut self) {
+    fn handle_openxr_events(&mut self) -> bool {
         use openxr::Event::*;
         loop {
             let mut buffer = openxr::EventDataBuffer::new();
@@ -275,12 +273,18 @@ impl OpenXrDevice {
                     openxr::SessionState::STOPPING => {
                         self.events.callback(Event::SessionEnd);
                         self.session.end().unwrap();
-                        self.is_running = false;
+                        return false;
+                    }
+                    openxr::SessionState::EXITING | openxr::SessionState::LOSS_PENDING => {
+                        break;
                     }
                     _ => {
                         // FIXME: Handle other states
                     }
                 },
+                Some(InstanceLossPending(_)) => {
+                    break;
+                }
                 Some(_) => {
                     // FIXME: Handle other events
                 }
@@ -290,6 +294,7 @@ impl OpenXrDevice {
                 }
             }
         }
+        true
     }
 }
 
@@ -336,12 +341,11 @@ impl Device for OpenXrDevice {
         Views::Stereo(left_view, right_view)
     }
 
-    fn is_running(&self) -> bool {
-        self.is_running
-    }
-
-    fn wait_for_animation_frame(&mut self) -> Frame {
-        self.handle_openxr_events();
+    fn wait_for_animation_frame(&mut self) -> Option<Frame> {
+        if !self.handle_openxr_events() {
+            // Session is not running anymore.
+            return None;
+        }
         self.frame_state = self.frame_waiter.wait().expect("error waiting for frame");
         // XXXManishearth should we check frame_state.should_render?
         let (_view_flags, views) = self
@@ -361,11 +365,11 @@ impl Device for OpenXrDevice {
         } else {
             vec![]
         };
-        Frame {
+        Some(Frame {
             transform,
             inputs: vec![],
             events,
-        }
+        })
     }
 
     fn render_animation_frame(