1 files changed, 74 insertions, 0 deletions
diff --git a/examples/panic-result.rs b/examples/panic-result.rs
new file mode 100644
index 0000000..b1200a3
--- /dev/null
+++ b/examples/panic-result.rs
@@ -0,0 +1,74 @@
+//! A single-threaded executor where join handles catch panics inside tasks.
+
+#![feature(async_await)]
+
+use std::future::Future;
+use std::panic::AssertUnwindSafe;
+use std::thread;
+
+use crossbeam::channel::{unbounded, Sender};
+use futures::executor;
+use futures::future::FutureExt;
+use lazy_static::lazy_static;
+
+/// Spawns a future on the executor.
+fn spawn<F, R>(future: F) -> async_task::JoinHandle<thread::Result<R>, ()>
+where
+    F: Future<Output = R> + Send + 'static,
+    R: Send + 'static,
+{
+    lazy_static! {
+        // A channel that holds scheduled tasks.
+        static ref QUEUE: Sender<async_task::Task<()>> = {
+            let (sender, receiver) = unbounded::<async_task::Task<()>>();
+
+            // Start the executor thread.
+            thread::spawn(|| {
+                for task in receiver {
+                    // No need for `catch_unwind()` here because panics are already caught.
+                    task.run();
+                }
+            });
+
+            sender
+        };
+    }
+
+    // Create a future that catches panics within itself.
+    let future = AssertUnwindSafe(future).catch_unwind();
+
+    // Create a task that is scheduled by sending itself into the channel.
+    let schedule = |t| QUEUE.send(t).unwrap();
+    let (task, handle) = async_task::spawn(future, schedule, ());
+
+    // Schedule the task by sending it into the channel.
+    task.schedule();
+
+    handle
+}
+
+fn main() {
+    // Spawn a future that completes succesfully.
+    let handle = spawn(async {
+        println!("Hello, world!");
+    });
+
+    // Block on the future and report its result.
+    match executor::block_on(handle) {
+        None => println!("The task was cancelled."),
+        Some(Ok(val)) => println!("The task completed with {:?}", val),
+        Some(Err(_)) => println!("The task has panicked"),
+    }
+
+    // Spawn a future that panics.
+    let handle = spawn(async {
+        panic!("Ooops!");
+    });
+
+    // Block on the future and report its result.
+    match executor::block_on(handle) {
+        None => println!("The task was cancelled."),
+        Some(Ok(val)) => println!("The task completed with {:?}", val),
+        Some(Err(_)) => println!("The task has panicked"),
+    }
+}