From 9c145b513dce0ca0e71e3a35c99dda8af98f8b05 Mon Sep 17 00:00:00 2001
From: Gus Wynn <guswynn@gmail.com>
Date: Tue, 20 Apr 2021 13:01:44 -0700
Subject: [PATCH] potential async-std support

---
 .github/workflows/ci.yml |  2 ++
 Cargo.toml               |  6 ++++-
 src/adaptive/core.rs     |  9 +++++++
 src/lib.rs               | 56 ++++++++++++++++++++++++++++++++++++----
 4 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 569dd13..4963c8d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,6 +9,8 @@ jobs:
         run: rustup update stable
       - name: cargo test
         run: cargo test
+      - name: cargo test async_std
+        run: cargo test --no-default-features --features async-std-futures
   bench:
     name: Bench on nightly
     runs-on: ubuntu-latest
diff --git a/Cargo.toml b/Cargo.toml
index e32ae99..6699b0a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "impedance"
-version = "0.2.3"
+version = "0.2.4"
 authors = ["Gus Wynn <guswynn@gmail.com>"]
 edition = "2018"
 description = "Tools to mix blocking and async code"
@@ -11,8 +11,11 @@ license = "MIT OR Apache-2.0"
 
 [features]
 default = ["tokio"]
+async-std-futures = ["async-std", "futures"]
 
 [dependencies]
+async-std = { version = "1.9.0", features = ["unstable"], optional = true }
+futures = { version = "0.3.14", optional = true }
 once_cell = "1.7.2"
 parking_lot = "0.11.1"
 pin-project = "1.0.7"
@@ -22,3 +25,4 @@ tokio = { version = "1.5.0", features = ["rt", "sync"], optional = true }
 futures = "0.3.14"
 serde_json = "1.0.64"
 tokio = { version = "1.5.0", features = ["rt-multi-thread", "macros", "sync"] }
+async-std = { version = "1.9.0", features = ["unstable", "attributes"] }
diff --git a/src/adaptive/core.rs b/src/adaptive/core.rs
index b462ecd..3c8238b 100644
--- a/src/adaptive/core.rs
+++ b/src/adaptive/core.rs
@@ -9,6 +9,10 @@ use std::{
     time::{Duration, Instant},
 };
 // TODO(azw): support more executors
+#[cfg(feature = "async-std-futures")]
+use async_std::task::{spawn_blocking, JoinHandle};
+#[cfg(feature = "async-std-futures")]
+use futures::channel::oneshot::{channel, Receiver};
 #[cfg(feature = "tokio")]
 use tokio::{
     sync::oneshot::{channel, Receiver},
@@ -142,8 +146,13 @@ impl<O: Send + 'static, F: FnOnce() -> O + Send + 'static> Future for TimedBlock
                         _ => false,
                     };
 
+                    println!("GUS");
                     match Pin::new(jh).poll(cx) {
+                        #[cfg(feature = "async-std-futures")]
+                        Poll::Ready(val) => return Poll::Ready(val),
+                        #[cfg(feature = "tokio")]
                         Poll::Ready(Ok(val)) => return Poll::Ready(val),
+                        #[cfg(feature = "tokio")]
                         Poll::Ready(Err(e)) => match e.try_into_panic() {
                             Ok(panic) => {
                                 std::panic::resume_unwind(panic);
diff --git a/src/lib.rs b/src/lib.rs
index 274cdb5..d608775 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,12 +33,20 @@
 //!
 //! ## Features
 //! This library should be design in a way such that any executor that has a
-//! `spawn_blocking` method can be used. However, currently it only implements it for
-//! [`tokio`](tokio) which is in its `default_features`.
+//! `spawn_blocking` method can be used:
 //!
+// TODO(guswynn): can rustdoc auto make these links for me?
+//! - `tokio`: Currently this library tries to provide good support
+//! for [`tokio`](tokio) which is in its `default_features`.
+//! - `async-std-futures`: This library has experimental support for using [`async-std`](https://docs.rs/async-std) (as well as
+//! [`futures`](https://docs.rs/futures) internally for a oneshot channel). You will need to use `default-features
+//! = false`
+//! and there are caveats: First and foremost, panic payloads's are NOT ALWAYS propagated
+//! correctly, they have a default failed task message when the work was moved to a thread.
+//!   - TODO: consider [`async_executors`](https://docs.rs/async_executors) for this abstraction
 pub mod adaptive;
 
-#[cfg(test)]
+#[cfg(all(test, feature = "tokio"))]
 mod tests {
     use super::*;
     use adaptive::{AdaptiveFuture, Token};
@@ -69,7 +77,7 @@ mod tests {
     }
 
     #[tokio::test]
-    #[should_panic]
+    #[should_panic(expected = "gus")]
     async fn test_panic_adaptive() {
         let thing = AdaptiveFuture::new(Token::new(), || {
             if false {
@@ -82,7 +90,45 @@ mod tests {
     }
 
     #[tokio::test]
-    #[should_panic]
+    #[should_panic(expected = "gus")]
+    async fn test_panic_spawning() {
+        let thing = AdaptiveFuture::new(Token::always_spawn(), || {
+            if false {
+                1_isize
+            } else {
+                panic!("gus");
+            }
+        });
+        assert_eq!(1, thing.await);
+    }
+}
+
+#[cfg(all(test, feature = "async-std-futures"))]
+mod async_std_tests {
+    use super::*;
+    use adaptive::{AdaptiveFuture, Token};
+
+    #[async_std::test]
+    async fn test_basic() {
+        let thing = AdaptiveFuture::new(Token::new(), || 1);
+        assert_eq!(1, thing.await);
+    }
+
+    #[async_std::test]
+    #[should_panic(expected = "gus")]
+    async fn test_panic_adaptive() {
+        let thing = AdaptiveFuture::new(Token::new(), || {
+            if false {
+                1_isize
+            } else {
+                panic!("gus");
+            }
+        });
+        assert_eq!(1, thing.await);
+    }
+
+    #[async_std::test]
+    #[should_panic(expected = "task has failed")]
     async fn test_panic_spawning() {
         let thing = AdaptiveFuture::new(Token::always_spawn(), || {
             if false {