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use std::cell::Cell;
use std::mem;
use crossbeam_utils::CachePadded;
#[test]
fn default() {
let x: CachePadded<u64> = Default::default();
assert_eq!(*x, 0);
}
#[test]
fn store_u64() {
let x: CachePadded<u64> = CachePadded::new(17);
assert_eq!(*x, 17);
}
#[test]
fn store_pair() {
let x: CachePadded<(u64, u64)> = CachePadded::new((17, 37));
assert_eq!(x.0, 17);
assert_eq!(x.1, 37);
}
#[test]
fn distance() {
let arr = [CachePadded::new(17u8), CachePadded::new(37u8)];
let a = &*arr[0] as *const u8;
let b = &*arr[1] as *const u8;
let align = mem::align_of::<CachePadded<()>>();
assert!(align >= 32);
assert_eq!(unsafe { a.add(align) }, b);
}
#[test]
fn different_sizes() {
CachePadded::new(17u8);
CachePadded::new(17u16);
CachePadded::new(17u32);
CachePadded::new([17u64; 0]);
CachePadded::new([17u64; 1]);
CachePadded::new([17u64; 2]);
CachePadded::new([17u64; 3]);
CachePadded::new([17u64; 4]);
CachePadded::new([17u64; 5]);
CachePadded::new([17u64; 6]);
CachePadded::new([17u64; 7]);
CachePadded::new([17u64; 8]);
}
#[test]
fn large() {
let a = [17u64; 9];
let b = CachePadded::new(a);
assert!(mem::size_of_val(&a) <= mem::size_of_val(&b));
}
#[test]
fn debug() {
assert_eq!(
format!("{:?}", CachePadded::new(17u64)),
"CachePadded { value: 17 }"
);
}
#[test]
fn drops() {
let count = Cell::new(0);
struct Foo<'a>(&'a Cell<usize>);
impl<'a> Drop for Foo<'a> {
fn drop(&mut self) {
self.0.set(self.0.get() + 1);
}
}
let a = CachePadded::new(Foo(&count));
let b = CachePadded::new(Foo(&count));
assert_eq!(count.get(), 0);
drop(a);
assert_eq!(count.get(), 1);
drop(b);
assert_eq!(count.get(), 2);
}
#[allow(clippy::clone_on_copy)] // This is intentional.
#[test]
fn clone() {
let a = CachePadded::new(17);
let b = a.clone();
assert_eq!(*a, *b);
}
#[test]
fn runs_custom_clone() {
let count = Cell::new(0);
struct Foo<'a>(&'a Cell<usize>);
impl<'a> Clone for Foo<'a> {
fn clone(&self) -> Foo<'a> {
self.0.set(self.0.get() + 1);
Foo::<'a>(self.0)
}
}
let a = CachePadded::new(Foo(&count));
let _ = a.clone();
assert_eq!(count.get(), 1);
}