task -> thread

components/util/thread.rs

@@ -0,0 +1,66 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use ipc_channel::ipc::IpcSender;
+use serde::Serialize;
+use std::borrow::ToOwned;
+use std::sync::mpsc::Sender;
+use std::thread;
+use std::thread::Builder;
+use thread_state;
+
+pub fn spawn_named<F>(name: String, f: F)
+    where F: FnOnce() + Send + 'static
+{
+    let builder = thread::Builder::new().name(name);
+    builder.spawn(f).unwrap();
+}
+
+/// An abstraction over `Sender<T>` and `IpcSender<T>`, for use in
+/// `spawn_named_with_send_on_failure`.
+pub trait SendOnFailure {
+    type Value;
+    fn send_on_failure(&mut self, value: Self::Value);
+}
+
+impl<T> SendOnFailure for Sender<T> where T: Send + 'static {
+    type Value = T;
+    fn send_on_failure(&mut self, value: T) {
+        self.send(value).unwrap();
+    }
+}
+
+impl<T> SendOnFailure for IpcSender<T> where T: Send + Serialize + 'static {
+    type Value = T;
+    fn send_on_failure(&mut self, value: T) {
+        self.send(value).unwrap();
+    }
+}
+
+/// Arrange to send a particular message to a channel if the thread fails.
+pub fn spawn_named_with_send_on_failure<F, T, S>(name: String,
+                                                 state: thread_state::ThreadState,
+                                                 f: F,
+                                                 msg: T,
+                                                 mut dest: S)
+                                                 where F: FnOnce() + Send + 'static,
+                                                       T: Send + 'static,
+                                                       S: Send + SendOnFailure<Value=T> + 'static {
+    let future_handle = thread::Builder::new().name(name.to_owned()).spawn(move || {
+        thread_state::initialize(state);
+        f()
+    }).unwrap();
+
+    let watcher_name = format!("{}Watcher", name);
+    Builder::new().name(watcher_name).spawn(move || {
+        match future_handle.join() {
+            Ok(()) => (),
+            Err(..) => {
+                debug!("{} failed, notifying constellation", name);
+                dest.send_on_failure(msg);
+            }
+        }
+    }).unwrap();
+}
+