task_local context over context objects

- interner impls logically separate from API in orchid-base (default host interner still in base for testing)
- error reporting, logging, and a variety of other features passed down via context in extension, not yet in host to maintain library-ish profile, should consider options
- no global spawn mechanic, the host has a spawn function but extensions only get a stash for enqueuing async work in sync callbacks which is then explicitly, manually, and with strict order popped and awaited
- still deadlocks nondeterministically for some ungodly reason

orchid-base/src/stash.rs

@@ -1,16 +1,21 @@
 //! A pattern for running async code from sync destructors and other
 //! unfortunately sync callbacks
 //!
-//! We create a task_local
+//! We create a task_local vecdeque which is moved into a thread_local whenever
+//! the task is being polled. A call to [stash] pushes the future onto this
+//! deque. Before [with_stash] returns, it pops everything from the deque
+//! individually and awaits each of them, pushing any additionally stashed
+//! futures onto the back of the same deque.
 
+use std::cell::RefCell;
 use std::collections::VecDeque;
 use std::pin::Pin;
 
-use some_executor::task_local;
+use task_local::task_local;
 
 #[derive(Default)]
 struct StashedFutures {
-	queue: VecDeque<Pin<Box<dyn Future<Output = ()>>>>,
+	queue: RefCell<VecDeque<Pin<Box<dyn Future<Output = ()>>>>>,
 }
 
 task_local! {
@@ -23,7 +28,7 @@ pub async fn with_stash<F: Future>(fut: F) -> F::Output {
 	STASHED_FUTURES
 		.scope(StashedFutures::default(), async {
 			let val = fut.await;
-			while let Some(fut) = STASHED_FUTURES.with_mut(|sf| sf.unwrap().queue.pop_front()) {
+			while let Some(fut) = STASHED_FUTURES.with(|sf| sf.queue.borrow_mut().pop_front()) {
 				fut.await;
 			}
 			val
@@ -33,10 +38,7 @@ pub async fn with_stash<F: Future>(fut: F) -> F::Output {
 
 /// Schedule a future to be run before the next [with_stash] guard ends. This is
 /// most useful for sending messages from destructors.
-pub fn stash<F: Future + 'static>(fut: F) {
-	STASHED_FUTURES.with_mut(|sf| {
-		sf.expect("No stash! Timely completion cannot be guaranteed").queue.push_back(Box::pin(async {
-			fut.await;
-		}))
-	})
+pub fn stash<F: Future<Output = ()> + 'static>(fut: F) {
+	(STASHED_FUTURES.try_with(|sf| sf.queue.borrow_mut().push_back(Box::pin(fut))))
+		.expect("No stash! Timely completion cannot be guaranteed")
 }