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-rw-r--r--examples/spawn-on-thread.rs55
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diff --git a/examples/spawn-on-thread.rs b/examples/spawn-on-thread.rs
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+//! A function that runs a future to completion on a dedicated thread.
+
+#![feature(async_await)]
+
+use std::future::Future;
+use std::sync::Arc;
+use std::thread;
+
+use crossbeam::channel;
+use futures::executor;
+
+/// Spawns a future on a new dedicated thread.
+///
+/// The returned handle can be used to await the output of the future.
+fn spawn_on_thread<F, R>(future: F) -> async_task::JoinHandle<R, ()>
+where
+ F: Future<Output = R> + Send + 'static,
+ R: Send + 'static,
+{
+ // Create a channel that holds the task when it is scheduled for running.
+ let (sender, receiver) = channel::unbounded();
+ let sender = Arc::new(sender);
+ let s = Arc::downgrade(&sender);
+
+ // Wrap the future into one that disconnects the channel on completion.
+ let future = async move {
+ // When the inner future completes, the sender gets dropped and disconnects the channel.
+ let _sender = sender;
+ future.await
+ };
+
+ // Create a task that is scheduled by sending itself into the channel.
+ let schedule = move |t| s.upgrade().unwrap().send(t).unwrap();
+ let (task, handle) = async_task::spawn(future, schedule, ());
+
+ // Schedule the task by sending it into the channel.
+ task.schedule();
+
+ // Spawn a thread running the task to completion.
+ thread::spawn(move || {
+ // Keep taking the task from the channel and running it until completion.
+ for task in receiver {
+ task.run();
+ }
+ });
+
+ handle
+}
+
+fn main() {
+ // Spawn a future on a dedicated thread.
+ executor::block_on(spawn_on_thread(async {
+ println!("Hello, world!");
+ }));
+}