1 files changed, 44 insertions, 0 deletions
diff --git a/tokio/src/runtime/blocking/shutdown.rs b/tokio/src/runtime/blocking/shutdown.rs
new file mode 100644
index 00000000..d9f5eb0f
--- /dev/null
+++ b/tokio/src/runtime/blocking/shutdown.rs
@@ -0,0 +1,44 @@
+//! A shutdown channel.
+//!
+//! Each worker holds the `Sender` half. When all the `Sender` halves are
+//! dropped, the `Receiver` receives a notification.
+
+use crate::loom::sync::Arc;
+use crate::sync::oneshot;
+
+#[derive(Debug, Clone)]
+pub(super) struct Sender {
+    tx: Arc<oneshot::Sender<()>>,
+}
+
+#[derive(Debug)]
+pub(super) struct Receiver {
+    rx: oneshot::Receiver<()>,
+}
+
+pub(super) fn channel() -> (Sender, Receiver) {
+    let (tx, rx) = oneshot::channel();
+    let tx = Sender { tx: Arc::new(tx) };
+    let rx = Receiver { rx };
+
+    (tx, rx)
+}
+
+impl Receiver {
+    /// Block the current thread until all `Sender` handles drop.
+    pub(crate) fn wait(&mut self) {
+        use crate::runtime::enter::{enter, try_enter};
+
+        let mut e = if std::thread::panicking() {
+            match try_enter() {
+                Some(enter) => enter,
+                _ => return,
+            }
+        } else {
+            enter()
+        };
+
+        // The oneshot completes with an Err
+        let _ = e.block_on(&mut self.rx);
+    }
+}