diff --git a/rayon-core/Cargo.toml b/rayon-core/Cargo.toml index db7818899..0667f9504 100644 --- a/rayon-core/Cargo.toml +++ b/rayon-core/Cargo.toml @@ -55,3 +55,7 @@ path = "tests/simple_panic.rs" [[test]] name = "scoped_threadpool" path = "tests/scoped_threadpool.rs" + +[[test]] +name = "use_current_thread" +path = "tests/use_current_thread.rs" diff --git a/rayon-core/tests/use_current_thread.rs b/rayon-core/tests/use_current_thread.rs new file mode 100644 index 000000000..d72d3b235 --- /dev/null +++ b/rayon-core/tests/use_current_thread.rs @@ -0,0 +1,47 @@ +use rayon_core::ThreadPoolBuilder; +use std::sync::{Arc, Condvar, Mutex}; +use std::thread::{self, JoinHandle}; + +#[test] +fn use_current_thread_basic() { + static JOIN_HANDLES: Mutex>> = Mutex::new(Vec::new()); + let pool = ThreadPoolBuilder::new() + .num_threads(2) + .use_current_thread() + .spawn_handler(|builder| { + let handle = thread::Builder::new().spawn(|| builder.run())?; + JOIN_HANDLES.lock().unwrap().push(handle); + Ok(()) + }) + .build() + .unwrap(); + assert_eq!(rayon_core::current_thread_index(), Some(0)); + assert_eq!( + JOIN_HANDLES.lock().unwrap().len(), + 1, + "Should only spawn one extra thread" + ); + + let pair = Arc::new((Mutex::new(false), Condvar::new())); + let pair2 = Arc::clone(&pair); + pool.spawn(move || { + assert_ne!(rayon_core::current_thread_index(), Some(0)); + // This should execute even if the current thread is blocked, since we have two threads in + // the pool. + let &(ref started, ref condvar) = &*pair2; + *started.lock().unwrap() = true; + condvar.notify_one(); + }); + + let _guard = pair + .1 + .wait_while(pair.0.lock().unwrap(), |ran| !*ran) + .unwrap(); + std::mem::drop(pool); // Drop the pool. + + // Wait until all threads have actually exited. This is not really needed, other than to + // reduce noise of leak-checking tools. + for handle in std::mem::take(&mut *JOIN_HANDLES.lock().unwrap()) { + let _ = handle.join(); + } +}