Merge pull request #183 from Schmarni-Dev/better_oxr_events

make OpenXR event handlers completely safe! (no unsafe!)

crates/bevy_openxr/src/openxr/features/overlay.rs

@@ -7,7 +7,7 @@ use crate::{
     next_chain::{OxrNextChainStructBase, OxrNextChainStructProvider},
     openxr::exts::OxrEnabledExtensions,
     openxr_session_available,
-    poll_events::{OxrEvent, OxrEventHandlerExt},
+    poll_events::{OxrEventHandlerExt, OxrEventIn},
     session::{OxrSessionCreateNextChain, OxrSessionCreateNextProvider},
 };
 
@@ -25,9 +25,8 @@ impl Plugin for OxrOverlayPlugin {
     }
 }
 
-fn handle_overlay_event(event: In<OxrEvent>, mut writer: EventWriter<OxrOverlaySessionEvent>) {
-    // this unwrap will never panic since we are in a valid scope
-    if let Event::MainSessionVisibilityChangedEXTX(event) = unsafe { event.get() }.unwrap() {
+fn handle_overlay_event(event: OxrEventIn, mut writer: EventWriter<OxrOverlaySessionEvent>) {
+    if let Event::MainSessionVisibilityChangedEXTX(event) = *event {
         writer.send(OxrOverlaySessionEvent::MainSessionVisibilityChanged {
             visible: event.visible(),
             flags: event.flags(),

crates/bevy_openxr/src/openxr/init.rs

@@ -27,7 +27,7 @@ use crate::session::OxrSessionCreateNextChain;
 use crate::types::*;
 
 use super::exts::OxrEnabledExtensions;
-use super::poll_events::OxrEvent;
+use super::poll_events::OxrEventIn;
 use super::poll_events::OxrEventHandlerExt;
 
 pub fn session_started(started: Option<Res<OxrSessionStarted>>) -> bool {
@@ -297,14 +297,13 @@ impl OxrInitPlugin {
 pub struct OxrInteractionProfileChanged;
 
 pub fn handle_events(
-    event: In<OxrEvent>,
+    event: OxrEventIn,
     mut status: ResMut<XrState>,
     mut changed_event: EventWriter<XrStateChanged>,
     mut interaction_profile_changed_event: EventWriter<OxrInteractionProfileChanged>,
 ) {
     use openxr::Event::*;
-    // this unwrap will never panic since we are in a valid scope
-    match unsafe { event.get() }.unwrap() {
+    match *event {
         SessionStateChanged(state) => {
             use openxr::SessionState;
 

crates/bevy_openxr/src/openxr/poll_events.rs

@@ -1,5 +1,3 @@
-use std::{cell::RefCell, mem, ops::Deref, rc::Rc};
-
 use bevy::{ecs::system::SystemId, prelude::*};
 use bevy_mod_xr::session::{XrFirst, XrHandleEvents};
 use openxr::{Event, EventDataBuffer};
@@ -27,63 +25,51 @@ pub fn poll_events(world: &mut World) {
         .poll_event(&mut buffer)
         .expect("Failed to poll event")
     {
-        let event = Rc::new(RefCell::new(Some(event)));
-        for handler in handlers.handlers.iter() {
-            if let Err(err) =
-                world.run_system_with_input::<_, ()>(*handler, OxrEvent::new(event.clone()))
+        for handler in handlers
+            .0
+            .iter()
+            .map(|v| SystemId::<OxrEventIn, ()>::from_entity(*v))
         {
+            if let Err(err) = world.run_system_with_input(handler, event) {
                 error!("error when running oxr event handler: {err}");
             };
         }
-        event.deref().take();
     }
     world.insert_resource(handlers);
 }
 
 use super::{openxr_session_available, resources::OxrInstance};
 #[derive(Resource, Debug, Default)]
-pub struct OxrEventHandlers {
-    pub handlers: Vec<OxrEventHandler>,
-}
-pub type OxrEventHandler = SystemId<In<OxrEvent>, ()>;
-
-pub struct OxrEvent {
-    event: Rc<RefCell<Option<Event<'static>>>>,
-}
-
-impl OxrEvent {
-    pub(crate) fn new(event: Rc<RefCell<Option<Event<'_>>>>) -> Self {
-        Self {
-            #[allow(clippy::missing_transmute_annotations)]
-            event: unsafe { mem::transmute(event) },
-        }
-    }
-    /// always returns [Some] if called in a valid scope
-    /// # Safety
-    /// The event is only valid for the duration of the poll event callback,
-    /// don't Store the [Event] anywhere!!
-    #[allow(clippy::needless_lifetimes)]
-    pub unsafe fn get<'a>(&'a self) -> Option<Event<'a>> {
-        *self.event.borrow()
-    }
-}
+pub struct OxrEventHandlers(Vec<Entity>);
 pub trait OxrEventHandlerExt {
     fn add_oxr_event_handler<M>(
         &mut self,
-        system: impl IntoSystem<In<OxrEvent>, (), M> + 'static,
+        system: impl IntoSystem<OxrEventIn<'static>, (), M> + 'static,
     ) -> &mut Self;
 }
 impl OxrEventHandlerExt for App {
     fn add_oxr_event_handler<M>(
         &mut self,
-        system: impl IntoSystem<In<OxrEvent>, (), M> + 'static,
+        system: impl IntoSystem<OxrEventIn<'static>, (), M> + 'static,
     ) -> &mut Self {
         self.init_resource::<OxrEventHandlers>();
         let id = self.register_system(system);
         self.world_mut()
             .resource_mut::<OxrEventHandlers>()
-            .handlers
-            .push(id);
+            .0
+            .push(id.entity());
         self
     }
 }
+
+#[derive(Deref)]
+pub struct OxrEventIn<'a>(pub Event<'a>);
+impl SystemInput for OxrEventIn<'_> {
+    type Param<'i> = OxrEventIn<'i>;
+
+    type Inner<'i> = Event<'i>;
+
+    fn wrap(this: Self::Inner<'_>) -> Self::Param<'_> {
+        OxrEventIn(this)
+    }
+}