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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /library/core/tests/lazy.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/core/tests/lazy.rs')
-rw-r--r--library/core/tests/lazy.rs138
1 files changed, 138 insertions, 0 deletions
diff --git a/library/core/tests/lazy.rs b/library/core/tests/lazy.rs
new file mode 100644
index 000000000..70fcc6d2d
--- /dev/null
+++ b/library/core/tests/lazy.rs
@@ -0,0 +1,138 @@
+use core::{
+ cell::{Cell, LazyCell, OnceCell},
+ sync::atomic::{AtomicUsize, Ordering::SeqCst},
+};
+
+#[test]
+fn once_cell() {
+ let c = OnceCell::new();
+ assert!(c.get().is_none());
+ c.get_or_init(|| 92);
+ assert_eq!(c.get(), Some(&92));
+
+ c.get_or_init(|| panic!("Kabom!"));
+ assert_eq!(c.get(), Some(&92));
+}
+
+#[test]
+fn once_cell_get_mut() {
+ let mut c = OnceCell::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 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 = OnceCell::new();
+ x.get_or_init(|| Dropper);
+ assert_eq!(DROP_CNT.load(SeqCst), 0);
+ drop(x);
+ assert_eq!(DROP_CNT.load(SeqCst), 1);
+}
+
+#[test]
+fn unsync_once_cell_drop_empty() {
+ let x = OnceCell::<&'static str>::new();
+ drop(x);
+}
+
+#[test]
+const fn once_cell_const() {
+ let _once_cell: OnceCell<u32> = OnceCell::new();
+ let _once_cell: OnceCell<u32> = OnceCell::from(32);
+}
+
+#[test]
+fn clone() {
+ let s = OnceCell::new();
+ let c = s.clone();
+ assert!(c.get().is_none());
+
+ s.set("hello").unwrap();
+ let c = s.clone();
+ assert_eq!(c.get().map(|c| *c), Some("hello"));
+}
+
+#[test]
+fn from_impl() {
+ assert_eq!(OnceCell::from("value").get(), Some(&"value"));
+ assert_ne!(OnceCell::from("foo").get(), Some(&"bar"));
+}
+
+#[test]
+fn partialeq_impl() {
+ assert!(OnceCell::from("value") == OnceCell::from("value"));
+ assert!(OnceCell::from("foo") != OnceCell::from("bar"));
+
+ assert!(OnceCell::<&'static str>::new() == OnceCell::new());
+ assert!(OnceCell::<&'static str>::new() != OnceCell::from("value"));
+}
+
+#[test]
+fn into_inner() {
+ let cell: OnceCell<&'static str> = OnceCell::new();
+ assert_eq!(cell.into_inner(), None);
+ let cell = OnceCell::new();
+ cell.set("hello").unwrap();
+ assert_eq!(cell.into_inner(), Some("hello"));
+}
+
+#[test]
+fn lazy_new() {
+ let called = Cell::new(0);
+ let x = LazyCell::new(|| {
+ called.set(called.get() + 1);
+ 92
+ });
+
+ assert_eq!(called.get(), 0);
+
+ let y = *x - 30;
+ assert_eq!(y, 62);
+ assert_eq!(called.get(), 1);
+
+ let y = *x - 30;
+ assert_eq!(y, 62);
+ assert_eq!(called.get(), 1);
+}
+
+#[test]
+fn aliasing_in_get() {
+ let x = OnceCell::new();
+ x.set(42).unwrap();
+ let at_x = x.get().unwrap(); // --- (shared) borrow of inner `Option<T>` --+
+ let _ = x.set(27); // <-- temporary (unique) borrow of inner `Option<T>` |
+ println!("{at_x}"); // <------- up until here ---------------------------+
+}
+
+#[test]
+#[should_panic(expected = "reentrant init")]
+fn reentrant_init() {
+ let x: OnceCell<Box<i32>> = OnceCell::new();
+ let dangling_ref: Cell<Option<&i32>> = Cell::new(None);
+ x.get_or_init(|| {
+ let r = x.get_or_init(|| Box::new(92));
+ dangling_ref.set(Some(r));
+ Box::new(62)
+ });
+ eprintln!("use after free: {:?}", dangling_ref.get().unwrap());
+}
+
+#[test]
+fn dropck() {
+ let cell = OnceCell::new();
+ {
+ let s = String::new();
+ cell.set(&s).unwrap();
+ }
+}