move world pointers to thread locals

crates/bevy_mod_scripting_core/src/bindings/world.rs

@@ -24,6 +24,7 @@ use bevy::{
 };
 use std::{
     any::TypeId,
+    cell::RefCell,
     fmt::Debug,
     sync::{Arc, Weak},
     time::Duration,
@@ -946,6 +947,51 @@ impl WorldAccessGuard<'_> {
     }
 }
 
+/// Utility type for accessing the world in a callback
+pub trait WorldContainer {
+    type Error: Debug;
+    /// Sets the world to the given value
+    fn set_world(&mut self, world: WorldCallbackAccess) -> Result<(), Self::Error>;
+
+    /// Gets the world, use [`WorldContainer::try_get_world`] if you want to handle errors with retrieving the world
+    /// # Panics
+    /// - if the world has not been set
+    /// - if the world has been dropped
+    fn get_world(&self) -> WorldGuard<'static> {
+        self.try_get_world().expect("World not set, or expired")
+    }
+
+    /// Tries to get the world
+    fn try_get_world(&self) -> Result<Arc<WorldAccessGuard<'static>>, Self::Error>;
+}
+
+/// A world container that stores the world in a thread local
+pub struct ThreadWorldContainer;
+
+thread_local! {
+    static WORLD_CALLBACK_ACCESS: RefCell<Option<WorldCallbackAccess>> = const { RefCell::new(None) };
+}
+
+impl WorldContainer for ThreadWorldContainer {
+    type Error = InteropError;
+
+    fn set_world(&mut self, world: WorldCallbackAccess) -> Result<(), Self::Error> {
+        WORLD_CALLBACK_ACCESS.with(|w| {
+            w.replace(Some(world));
+        });
+        Ok(())
+    }
+
+    fn try_get_world(&self) -> Result<Arc<WorldAccessGuard<'static>>, Self::Error> {
+        WORLD_CALLBACK_ACCESS.with(|w| {
+            w.borrow()
+                .as_ref()
+                .map(|w| w.try_read())
+                .ok_or_else(InteropError::missing_world)
+        })?
+    }
+}
+
 // #[cfg(test)]
 // mod test {
 //     use crate::bindings::ScriptTypeRegistration;

crates/bevy_mod_scripting_core/src/lib.rs

@@ -36,7 +36,6 @@ pub mod reflection_extensions;
 pub mod runtime;
 pub mod script;
 pub mod systems;
-pub mod world;
 
 /// Types which act like scripting plugins, by selecting a context and runtime
 /// Each individual combination of context and runtime has specific infrastructure built for it and does not interact with other scripting plugins