Replacing threadpool with futures::executor for runtime-polyfill

.ci/lints-stage.yml

@@ -21,6 +21,7 @@ stages:
 
                 - script: |
                       rustup component add clippy --toolchain nightly
-                      cargo +nightly clippy --all-targets --all-features -- -D warnings
+                      cargo +nightly clippy --all-targets --no-default-features--features runtime-polyfill -- -D warnings
+                      cargo +nightly clippy --all-targets --no-default-features--features runtime-tokio -- -D warnings
                   displayName: Run clippy
                   continueOnError: true

heim-runtime/Cargo.toml

@@ -14,7 +14,6 @@ heim-common = { version = "0.0.6", path = "../heim-common" }
 cfg-if = "0.1.9"
 
 # `runtime-polyfill` feature dependencies
-threadpool = { version = "1.7.1", optional = true }
 lazy_static = { version = "1.3.0", optional = true }
 futures-preview = { version = "0.3.0-alpha.17", optional = true }
 
@@ -28,5 +27,5 @@ version-sync = "0.8"
 
 [features]
 default = ["runtime-polyfill"]
-runtime-polyfill = ["threadpool", "lazy_static", "futures-preview"]
+runtime-polyfill = ["lazy_static", "futures-preview"]
 runtime-tokio = ["tokio", "tokio-fs"]

heim-runtime/src/shims/sync/pool.rs

@@ -1,9 +1,10 @@
 use std::fmt::Debug;
 use std::sync::Mutex;
 
+use futures::executor::ThreadPool;
 use futures::channel::oneshot;
-use futures::future::Future;
-use threadpool::ThreadPool;
+use futures::future::{self, Future};
+use futures::task::Spawn;
 
 use heim_common::prelude::*;
 
@@ -16,20 +17,31 @@ pub struct FuturePool(Mutex<ThreadPool>);
 
 impl FuturePool {
     pub fn new() -> FuturePool {
-        FuturePool(Mutex::new(ThreadPool::default()))
+        let inner = ThreadPool::builder()
+            .name_prefix("heim-")
+            .create()
+            .expect("Misconfigured thread pool");
+
+        FuturePool(Mutex::new(inner))
     }
 
     pub fn spawn<F, T>(&self, f: F) -> impl Future<Output = T>
     where
         F: FnOnce() -> T + Send + 'static,
         T: Send + Debug + 'static,
     {
-        let pool = self.0.lock().expect("Thread pool mutex is poisoned");
 
         let (tx, rx) = oneshot::channel();
-        pool.execute(move || {
-            let _ = tx.send(f());
-        });
+        let fut: future::FutureObj<()> = future::lazy(|_| {
+                let _ = tx.send(f());
+            })
+            .boxed()
+            .into();
+
+        {
+            let mut pool = self.0.lock().expect("Futures pool mutex is poisoned");
+            let _ = pool.spawn_obj(fut);
+        }
 
         rx.map(|res| res.expect("Runtime future was canceled"))
     }