mirror of
https://git.proxmox.com/git/rustc
synced 2025-08-16 23:31:07 +00:00
522 lines
14 KiB
Rust
522 lines
14 KiB
Rust
mod unsync {
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use core::{
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cell::Cell,
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sync::atomic::{AtomicUsize, Ordering::SeqCst},
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};
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use once_cell::unsync::{Lazy, OnceCell};
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#[test]
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fn once_cell() {
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let c = OnceCell::new();
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assert!(c.get().is_none());
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c.get_or_init(|| 92);
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assert_eq!(c.get(), Some(&92));
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c.get_or_init(|| panic!("Kabom!"));
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assert_eq!(c.get(), Some(&92));
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}
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#[test]
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fn once_cell_get_mut() {
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let mut c = OnceCell::new();
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assert!(c.get_mut().is_none());
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c.set(90).unwrap();
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*c.get_mut().unwrap() += 2;
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assert_eq!(c.get_mut(), Some(&mut 92));
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}
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#[test]
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fn once_cell_drop() {
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static DROP_CNT: AtomicUsize = AtomicUsize::new(0);
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struct Dropper;
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impl Drop for Dropper {
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fn drop(&mut self) {
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DROP_CNT.fetch_add(1, SeqCst);
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}
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}
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let x = OnceCell::new();
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x.get_or_init(|| Dropper);
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assert_eq!(DROP_CNT.load(SeqCst), 0);
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drop(x);
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assert_eq!(DROP_CNT.load(SeqCst), 1);
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}
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#[test]
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fn unsync_once_cell_drop_empty() {
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let x = OnceCell::<String>::new();
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drop(x);
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}
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#[test]
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fn clone() {
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let s = OnceCell::new();
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let c = s.clone();
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assert!(c.get().is_none());
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s.set("hello".to_string()).unwrap();
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let c = s.clone();
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assert_eq!(c.get().map(String::as_str), Some("hello"));
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}
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#[test]
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fn from_impl() {
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assert_eq!(OnceCell::from("value").get(), Some(&"value"));
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assert_ne!(OnceCell::from("foo").get(), Some(&"bar"));
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}
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#[test]
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fn partialeq_impl() {
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assert!(OnceCell::from("value") == OnceCell::from("value"));
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assert!(OnceCell::from("foo") != OnceCell::from("bar"));
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assert!(OnceCell::<String>::new() == OnceCell::new());
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assert!(OnceCell::<String>::new() != OnceCell::from("value".to_owned()));
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}
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#[test]
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fn into_inner() {
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let cell: OnceCell<String> = OnceCell::new();
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assert_eq!(cell.into_inner(), None);
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let cell = OnceCell::new();
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cell.set("hello".to_string()).unwrap();
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assert_eq!(cell.into_inner(), Some("hello".to_string()));
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}
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#[test]
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fn debug_impl() {
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let cell = OnceCell::new();
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assert_eq!(format!("{:?}", cell), "OnceCell(Uninit)");
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cell.set("hello".to_string()).unwrap();
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assert_eq!(format!("{:?}", cell), "OnceCell(\"hello\")");
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}
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#[test]
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fn lazy_new() {
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let called = Cell::new(0);
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let x = Lazy::new(|| {
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called.set(called.get() + 1);
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92
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});
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assert_eq!(called.get(), 0);
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let y = *x - 30;
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assert_eq!(y, 62);
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assert_eq!(called.get(), 1);
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let y = *x - 30;
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assert_eq!(y, 62);
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assert_eq!(called.get(), 1);
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}
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#[test]
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fn lazy_default() {
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static CALLED: AtomicUsize = AtomicUsize::new(0);
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struct Foo(u8);
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impl Default for Foo {
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fn default() -> Self {
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CALLED.fetch_add(1, SeqCst);
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Foo(42)
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}
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}
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let lazy: Lazy<std::sync::Mutex<Foo>> = <_>::default();
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assert_eq!(CALLED.load(SeqCst), 0);
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assert_eq!(lazy.lock().unwrap().0, 42);
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assert_eq!(CALLED.load(SeqCst), 1);
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lazy.lock().unwrap().0 = 21;
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assert_eq!(lazy.lock().unwrap().0, 21);
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assert_eq!(CALLED.load(SeqCst), 1);
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}
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#[test]
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#[cfg(not(miri))] // miri doesn't support panics
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#[cfg(feature = "std")]
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fn lazy_poisoning() {
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let x: Lazy<String> = Lazy::new(|| panic!("kaboom"));
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for _ in 0..2 {
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let res = std::panic::catch_unwind(|| x.len());
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assert!(res.is_err());
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}
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}
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#[test]
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fn aliasing_in_get() {
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let x = once_cell::unsync::OnceCell::new();
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x.set(42).unwrap();
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let at_x = x.get().unwrap(); // --- (shared) borrow of inner `Option<T>` --+
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let _ = x.set(27); // <-- temporary (unique) borrow of inner `Option<T>` |
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println!("{}", at_x); // <------- up until here ---------------------------+
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}
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}
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#[cfg(feature = "std")]
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mod sync {
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use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
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use once_cell::sync::{Lazy, OnceCell};
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#[cfg(not(miri))] // miri doesn't support threads
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mod scope {
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pub(super) use crossbeam_utils::thread::scope;
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}
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#[cfg(miri)]
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mod scope {
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pub(super) struct Scope;
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#[cfg(miri)]
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impl Scope {
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pub(super) fn spawn(&self, f: impl FnOnce(())) {
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f(());
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}
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}
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#[cfg(miri)]
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pub(super) fn scope(f: impl FnOnce(&Scope)) -> Result<(), ()> {
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f(&Scope);
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Ok(())
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}
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}
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use scope::scope;
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#[test]
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fn once_cell() {
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let c = OnceCell::new();
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assert!(c.get().is_none());
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scope(|s| {
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s.spawn(|_| {
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c.get_or_init(|| 92);
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assert_eq!(c.get(), Some(&92));
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});
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})
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.unwrap();
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c.get_or_init(|| panic!("Kabom!"));
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assert_eq!(c.get(), Some(&92));
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}
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#[test]
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fn once_cell_get_mut() {
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let mut c = OnceCell::new();
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assert!(c.get_mut().is_none());
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c.set(90).unwrap();
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*c.get_mut().unwrap() += 2;
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assert_eq!(c.get_mut(), Some(&mut 92));
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}
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#[test]
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fn once_cell_drop() {
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static DROP_CNT: AtomicUsize = AtomicUsize::new(0);
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struct Dropper;
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impl Drop for Dropper {
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fn drop(&mut self) {
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DROP_CNT.fetch_add(1, SeqCst);
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}
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}
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let x = OnceCell::new();
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scope(|s| {
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s.spawn(|_| {
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x.get_or_init(|| Dropper);
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assert_eq!(DROP_CNT.load(SeqCst), 0);
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drop(x);
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});
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})
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.unwrap();
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assert_eq!(DROP_CNT.load(SeqCst), 1);
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}
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#[test]
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fn once_cell_drop_empty() {
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let x = OnceCell::<String>::new();
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drop(x);
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}
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#[test]
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fn clone() {
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let s = OnceCell::new();
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let c = s.clone();
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assert!(c.get().is_none());
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s.set("hello".to_string()).unwrap();
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let c = s.clone();
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assert_eq!(c.get().map(String::as_str), Some("hello"));
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}
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#[test]
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#[cfg(not(miri))] // miri doesn't support panics
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fn get_or_try_init() {
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let cell: OnceCell<String> = OnceCell::new();
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assert!(cell.get().is_none());
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let res =
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std::panic::catch_unwind(|| cell.get_or_try_init(|| -> Result<_, ()> { panic!() }));
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assert!(res.is_err());
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assert!(cell.get().is_none());
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assert_eq!(cell.get_or_try_init(|| Err(())), Err(()));
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assert_eq!(
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cell.get_or_try_init(|| Ok::<_, ()>("hello".to_string())),
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Ok(&"hello".to_string())
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);
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assert_eq!(cell.get(), Some(&"hello".to_string()));
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}
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#[test]
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fn from_impl() {
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assert_eq!(OnceCell::from("value").get(), Some(&"value"));
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assert_ne!(OnceCell::from("foo").get(), Some(&"bar"));
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}
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#[test]
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fn partialeq_impl() {
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assert!(OnceCell::from("value") == OnceCell::from("value"));
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assert!(OnceCell::from("foo") != OnceCell::from("bar"));
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assert!(OnceCell::<String>::new() == OnceCell::new());
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assert!(OnceCell::<String>::new() != OnceCell::from("value".to_owned()));
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}
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#[test]
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fn into_inner() {
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let cell: OnceCell<String> = OnceCell::new();
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assert_eq!(cell.into_inner(), None);
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let cell = OnceCell::new();
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cell.set("hello".to_string()).unwrap();
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assert_eq!(cell.into_inner(), Some("hello".to_string()));
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}
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#[test]
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fn debug_impl() {
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let cell = OnceCell::new();
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assert_eq!(format!("{:#?}", cell), "OnceCell(Uninit)");
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cell.set(vec!["hello", "world"]).unwrap();
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assert_eq!(
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format!("{:#?}", cell),
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r#"OnceCell(
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[
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"hello",
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"world",
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],
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)"#
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);
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}
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#[test]
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#[cfg(not(miri))] // miri doesn't support processes
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fn reentrant_init() {
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let examples_dir = {
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let mut exe = std::env::current_exe().unwrap();
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exe.pop();
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exe.pop();
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exe.push("examples");
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exe
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};
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let bin = examples_dir
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.join("reentrant_init_deadlocks")
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.with_extension(std::env::consts::EXE_EXTENSION);
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let mut guard = Guard { child: std::process::Command::new(bin).spawn().unwrap() };
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std::thread::sleep(std::time::Duration::from_secs(2));
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let status = guard.child.try_wait().unwrap();
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assert!(status.is_none());
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struct Guard {
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child: std::process::Child,
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}
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impl Drop for Guard {
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fn drop(&mut self) {
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let _ = self.child.kill();
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}
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}
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}
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#[test]
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fn lazy_new() {
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let called = AtomicUsize::new(0);
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let x = Lazy::new(|| {
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called.fetch_add(1, SeqCst);
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92
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});
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assert_eq!(called.load(SeqCst), 0);
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scope(|s| {
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s.spawn(|_| {
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let y = *x - 30;
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assert_eq!(y, 62);
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assert_eq!(called.load(SeqCst), 1);
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});
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})
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.unwrap();
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let y = *x - 30;
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assert_eq!(y, 62);
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assert_eq!(called.load(SeqCst), 1);
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}
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#[test]
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fn lazy_default() {
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static CALLED: AtomicUsize = AtomicUsize::new(0);
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struct Foo(u8);
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impl Default for Foo {
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fn default() -> Self {
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CALLED.fetch_add(1, SeqCst);
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Foo(42)
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}
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}
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let lazy: Lazy<std::sync::Mutex<Foo>> = <_>::default();
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assert_eq!(CALLED.load(SeqCst), 0);
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assert_eq!(lazy.lock().unwrap().0, 42);
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assert_eq!(CALLED.load(SeqCst), 1);
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lazy.lock().unwrap().0 = 21;
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assert_eq!(lazy.lock().unwrap().0, 21);
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assert_eq!(CALLED.load(SeqCst), 1);
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}
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#[test]
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#[cfg(not(miri))] // leaks memory
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fn static_lazy() {
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static XS: Lazy<Vec<i32>> = Lazy::new(|| {
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let mut xs = Vec::new();
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xs.push(1);
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xs.push(2);
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xs.push(3);
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xs
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});
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scope(|s| {
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s.spawn(|_| {
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assert_eq!(&*XS, &vec![1, 2, 3]);
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});
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})
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.unwrap();
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assert_eq!(&*XS, &vec![1, 2, 3]);
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}
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#[test]
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#[cfg(not(miri))] // leaks memory
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fn static_lazy_via_fn() {
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fn xs() -> &'static Vec<i32> {
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static XS: OnceCell<Vec<i32>> = OnceCell::new();
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XS.get_or_init(|| {
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let mut xs = Vec::new();
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xs.push(1);
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xs.push(2);
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xs.push(3);
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xs
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})
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}
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assert_eq!(xs(), &vec![1, 2, 3]);
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}
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#[test]
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#[cfg(not(miri))] // miri doesn't support panics
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fn lazy_poisoning() {
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let x: Lazy<String> = Lazy::new(|| panic!("kaboom"));
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for _ in 0..2 {
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let res = std::panic::catch_unwind(|| x.len());
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assert!(res.is_err());
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}
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}
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#[test]
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fn once_cell_is_sync_send() {
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fn assert_traits<T: Send + Sync>() {}
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assert_traits::<OnceCell<String>>();
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assert_traits::<Lazy<String>>();
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}
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#[test]
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#[cfg(not(miri))] // leaks memory
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fn eval_once_macro() {
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macro_rules! eval_once {
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(|| -> $ty:ty {
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$($body:tt)*
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}) => {{
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static ONCE_CELL: OnceCell<$ty> = OnceCell::new();
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fn init() -> $ty {
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$($body)*
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}
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ONCE_CELL.get_or_init(init)
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}};
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}
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let fib: &'static Vec<i32> = eval_once! {
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|| -> Vec<i32> {
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let mut res = vec![1, 1];
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for i in 0..10 {
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let next = res[i] + res[i + 1];
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res.push(next);
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}
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res
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}
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};
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assert_eq!(fib[5], 8)
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}
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#[test]
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#[cfg(not(miri))] // deadlocks without real threads
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fn once_cell_does_not_leak_partially_constructed_boxes() {
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let n_tries = 100;
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let n_readers = 10;
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let n_writers = 3;
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const MSG: &str = "Hello, World";
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for _ in 0..n_tries {
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let cell: OnceCell<String> = OnceCell::new();
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scope(|scope| {
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for _ in 0..n_readers {
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scope.spawn(|_| loop {
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if let Some(msg) = cell.get() {
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assert_eq!(msg, MSG);
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break;
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}
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});
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}
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for _ in 0..n_writers {
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scope.spawn(|_| cell.set(MSG.to_owned()));
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}
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})
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.unwrap()
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}
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}
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#[test]
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#[cfg(not(miri))] // miri doesn't support Barrier
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fn get_does_not_block() {
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use std::sync::Barrier;
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let cell = OnceCell::new();
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let barrier = Barrier::new(2);
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scope(|scope| {
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scope.spawn(|_| {
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cell.get_or_init(|| {
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barrier.wait();
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barrier.wait();
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"hello".to_string()
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});
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});
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barrier.wait();
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assert_eq!(cell.get(), None);
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barrier.wait();
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})
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.unwrap();
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assert_eq!(cell.get(), Some(&"hello".to_string()));
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}
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}
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