| use crate::{ |
| panic, |
| sync::OnceLock, |
| sync::{ |
| atomic::{AtomicUsize, Ordering::SeqCst}, |
| mpsc::channel, |
| }, |
| thread, |
| }; |
| |
| fn spawn_and_wait<R: Send + 'static>(f: impl FnOnce() -> R + Send + 'static) -> R { |
| thread::spawn(f).join().unwrap() |
| } |
| |
| #[test] |
| #[cfg_attr(target_os = "emscripten", ignore)] |
| fn sync_once_cell() { |
| static ONCE_CELL: OnceLock<i32> = OnceLock::new(); |
| |
| assert!(ONCE_CELL.get().is_none()); |
| |
| spawn_and_wait(|| { |
| ONCE_CELL.get_or_init(|| 92); |
| assert_eq!(ONCE_CELL.get(), Some(&92)); |
| }); |
| |
| ONCE_CELL.get_or_init(|| panic!("Kabom!")); |
| assert_eq!(ONCE_CELL.get(), Some(&92)); |
| } |
| |
| #[test] |
| fn sync_once_cell_get_mut() { |
| let mut c = OnceLock::new(); |
| assert!(c.get_mut().is_none()); |
| c.set(90).unwrap(); |
| *c.get_mut().unwrap() += 2; |
| assert_eq!(c.get_mut(), Some(&mut 92)); |
| } |
| |
| #[test] |
| fn sync_once_cell_get_unchecked() { |
| let c = OnceLock::new(); |
| c.set(92).unwrap(); |
| unsafe { |
| assert_eq!(c.get_unchecked(), &92); |
| } |
| } |
| |
| #[test] |
| #[cfg_attr(target_os = "emscripten", ignore)] |
| fn sync_once_cell_drop() { |
| static DROP_CNT: AtomicUsize = AtomicUsize::new(0); |
| struct Dropper; |
| impl Drop for Dropper { |
| fn drop(&mut self) { |
| DROP_CNT.fetch_add(1, SeqCst); |
| } |
| } |
| |
| let x = OnceLock::new(); |
| spawn_and_wait(move || { |
| x.get_or_init(|| Dropper); |
| assert_eq!(DROP_CNT.load(SeqCst), 0); |
| drop(x); |
| }); |
| |
| assert_eq!(DROP_CNT.load(SeqCst), 1); |
| } |
| |
| #[test] |
| fn sync_once_cell_drop_empty() { |
| let x = OnceLock::<String>::new(); |
| drop(x); |
| } |
| |
| #[test] |
| fn clone() { |
| let s = OnceLock::new(); |
| let c = s.clone(); |
| assert!(c.get().is_none()); |
| |
| s.set("hello".to_string()).unwrap(); |
| let c = s.clone(); |
| assert_eq!(c.get().map(String::as_str), Some("hello")); |
| } |
| |
| #[test] |
| fn get_or_try_init() { |
| let cell: OnceLock<String> = OnceLock::new(); |
| assert!(cell.get().is_none()); |
| |
| let res = panic::catch_unwind(|| cell.get_or_try_init(|| -> Result<_, ()> { panic!() })); |
| assert!(res.is_err()); |
| assert!(!cell.is_initialized()); |
| assert!(cell.get().is_none()); |
| |
| assert_eq!(cell.get_or_try_init(|| Err(())), Err(())); |
| |
| assert_eq!(cell.get_or_try_init(|| Ok::<_, ()>("hello".to_string())), Ok(&"hello".to_string())); |
| assert_eq!(cell.get(), Some(&"hello".to_string())); |
| } |
| |
| #[test] |
| fn from_impl() { |
| assert_eq!(OnceLock::from("value").get(), Some(&"value")); |
| assert_ne!(OnceLock::from("foo").get(), Some(&"bar")); |
| } |
| |
| #[test] |
| fn partialeq_impl() { |
| assert!(OnceLock::from("value") == OnceLock::from("value")); |
| assert!(OnceLock::from("foo") != OnceLock::from("bar")); |
| |
| assert!(OnceLock::<String>::new() == OnceLock::new()); |
| assert!(OnceLock::<String>::new() != OnceLock::from("value".to_owned())); |
| } |
| |
| #[test] |
| fn into_inner() { |
| let cell: OnceLock<String> = OnceLock::new(); |
| assert_eq!(cell.into_inner(), None); |
| let cell = OnceLock::new(); |
| cell.set("hello".to_string()).unwrap(); |
| assert_eq!(cell.into_inner(), Some("hello".to_string())); |
| } |
| |
| #[test] |
| fn is_sync_send() { |
| fn assert_traits<T: Send + Sync>() {} |
| assert_traits::<OnceLock<String>>(); |
| } |
| |
| #[test] |
| fn eval_once_macro() { |
| macro_rules! eval_once { |
| (|| -> $ty:ty { |
| $($body:tt)* |
| }) => {{ |
| static ONCE_CELL: OnceLock<$ty> = OnceLock::new(); |
| fn init() -> $ty { |
| $($body)* |
| } |
| ONCE_CELL.get_or_init(init) |
| }}; |
| } |
| |
| let fib: &'static Vec<i32> = eval_once! { |
| || -> Vec<i32> { |
| let mut res = vec![1, 1]; |
| for i in 0..10 { |
| let next = res[i] + res[i + 1]; |
| res.push(next); |
| } |
| res |
| } |
| }; |
| assert_eq!(fib[5], 8) |
| } |
| |
| #[test] |
| #[cfg_attr(target_os = "emscripten", ignore)] |
| fn sync_once_cell_does_not_leak_partially_constructed_boxes() { |
| static ONCE_CELL: OnceLock<String> = OnceLock::new(); |
| |
| let n_readers = 10; |
| let n_writers = 3; |
| const MSG: &str = "Hello, World"; |
| |
| let (tx, rx) = channel(); |
| |
| for _ in 0..n_readers { |
| let tx = tx.clone(); |
| thread::spawn(move || { |
| loop { |
| if let Some(msg) = ONCE_CELL.get() { |
| tx.send(msg).unwrap(); |
| break; |
| } |
| #[cfg(target_env = "sgx")] |
| crate::thread::yield_now(); |
| } |
| }); |
| } |
| for _ in 0..n_writers { |
| thread::spawn(move || { |
| let _ = ONCE_CELL.set(MSG.to_owned()); |
| }); |
| } |
| |
| for _ in 0..n_readers { |
| let msg = rx.recv().unwrap(); |
| assert_eq!(msg, MSG); |
| } |
| } |
| |
| #[test] |
| fn dropck() { |
| let cell = OnceLock::new(); |
| { |
| let s = String::new(); |
| cell.set(&s).unwrap(); |
| } |
| } |