Switch build_scoped to std::thread::scope (Rust 1.63)

(cherry picked from commit e39b730)

Author: cuviper

rayon-core/src/lib.rs

@@ -309,12 +309,12 @@ where
 impl ThreadPoolBuilder {
     /// Creates a scoped `ThreadPool` initialized using this configuration.
     ///
-    /// This is a convenience function for building a pool using [`crossbeam::scope`]
+    /// This is a convenience function for building a pool using [`std::thread::scope`]
     /// to spawn threads in a [`spawn_handler`](#method.spawn_handler).
     /// The threads in this pool will start by calling `wrapper`, which should
     /// do initialization and continue by calling `ThreadBuilder::run()`.
     ///
-    /// [`crossbeam::scope`]: https://docs.rs/crossbeam/0.8/crossbeam/fn.scope.html
+    /// [`std::thread::scope`]: https://doc.rust-lang.org/std/thread/fn.scope.html
     ///
     /// # Examples
     ///
@@ -349,18 +349,17 @@ impl ThreadPoolBuilder {
         W: Fn(ThreadBuilder) + Sync, // expected to call `run()`
         F: FnOnce(&ThreadPool) -> R,
     {
-        let result = crossbeam_utils::thread::scope(|scope| {
-            let wrapper = &wrapper;
+        std::thread::scope(|scope| {
             let pool = self
                 .spawn_handler(|thread| {
-                    let mut builder = scope.builder();
+                    let mut builder = std::thread::Builder::new();
                     if let Some(name) = thread.name() {
                         builder = builder.name(name.to_string());
                     }
                     if let Some(size) = thread.stack_size() {
                         builder = builder.stack_size(size);
                     }
-                    builder.spawn(move |_| wrapper(thread))?;
+                    builder.spawn_scoped(scope, || wrapper(thread))?;
                     Ok(())
                 })
                 .build()?;
@@ -370,12 +369,7 @@ impl ThreadPoolBuilder {
                 Ok(result) => Ok(result),
                 Err(err) => unwind::resume_unwinding(err),
             }
-        });
-
-        match result {
-            Ok(result) => result,
-            Err(err) => unwind::resume_unwinding(err),
-        }
+        })
     }
 }
 
@@ -384,13 +378,11 @@ impl<S> ThreadPoolBuilder<S> {
     ///
     /// Note that the threads will not exit until after the pool is dropped. It
     /// is up to the caller to wait for thread termination if that is important
-    /// for any invariants. For instance, threads created in [`crossbeam::scope`]
+    /// for any invariants. For instance, threads created in [`std::thread::scope`]
     /// will be joined before that scope returns, and this will block indefinitely
     /// if the pool is leaked. Furthermore, the global thread pool doesn't terminate
     /// until the entire process exits!
     ///
-    /// [`crossbeam::scope`]: https://docs.rs/crossbeam/0.8/crossbeam/fn.scope.html
-    ///
     /// # Examples
     ///
     /// A minimal spawn handler just needs to call `run()` from an independent thread.
@@ -439,6 +431,7 @@ impl<S> ThreadPoolBuilder<S> {
     /// or [`std::thread::scope`] introduced in Rust 1.63, which is encapsulated in
     /// [`build_scoped`](#method.build_scoped).
     ///
+    /// [`crossbeam::scope`]: https://docs.rs/crossbeam/0.8/crossbeam/fn.scope.html
     /// [`std::thread::scope`]: https://doc.rust-lang.org/std/thread/fn.scope.html
     ///
     /// ```

rayon-core/tests/scoped_threadpool.rs

@@ -93,7 +93,7 @@ fn build_scoped_tls_threadpool() {
                     },
                 )
                 .expect("thread pool created");
-            // Internally, `crossbeam::scope` will wait for the threads to exit before returning.
+            // Internally, `std::thread::scope` will wait for the threads to exit before returning.
         });
     });
 }