rust/library/core/tests/cell.rs

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use core::cell::*;
use core::default::Default;
use std::mem::drop;
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#[test]
fn smoketest_unsafe_cell() {
let mut x = UnsafeCell::new(10);
let ref_mut = &mut x;
unsafe {
// The asserts are repeated in order to ensure that `get()`
// is non-mutating.
assert_eq!(*ref_mut.get(), 10);
assert_eq!(*ref_mut.get(), 10);
*ref_mut.get_mut() += 5;
assert_eq!(*ref_mut.get(), 15);
assert_eq!(*ref_mut.get(), 15);
assert_eq!(x.into_inner(), 15);
}
}
#[test]
fn unsafe_cell_raw_get() {
let x = UnsafeCell::new(10);
let ptr = &x as *const UnsafeCell<i32>;
unsafe {
// The asserts are repeated in order to ensure that `raw_get()`
// is non-mutating.
assert_eq!(*UnsafeCell::raw_get(ptr), 10);
assert_eq!(*UnsafeCell::raw_get(ptr), 10);
*UnsafeCell::raw_get(ptr) += 5;
assert_eq!(*UnsafeCell::raw_get(ptr), 15);
assert_eq!(*UnsafeCell::raw_get(ptr), 15);
assert_eq!(x.into_inner(), 15);
}
}
#[test]
fn smoketest_cell() {
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let x = Cell::new(10);
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assert_eq!(x, Cell::new(10));
assert_eq!(x.get(), 10);
x.set(20);
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assert_eq!(x, Cell::new(20));
assert_eq!(x.get(), 20);
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let y = Cell::new((30, 40));
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assert_eq!(y, Cell::new((30, 40)));
assert_eq!(y.get(), (30, 40));
}
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#[test]
fn cell_update() {
let x = Cell::new(10);
assert_eq!(x.update(|x| x + 5), 15);
assert_eq!(x.get(), 15);
assert_eq!(x.update(|x| x / 3), 5);
assert_eq!(x.get(), 5);
}
#[test]
fn cell_has_sensible_show() {
let x = Cell::new("foo bar");
assert!(format!("{x:?}").contains(x.get()));
x.set("baz qux");
assert!(format!("{x:?}").contains(x.get()));
}
#[test]
fn ref_and_refmut_have_sensible_show() {
let refcell = RefCell::new("foo");
let refcell_refmut = refcell.borrow_mut();
assert_eq!(format!("{refcell_refmut}"), "foo"); // Display
assert!(format!("{refcell_refmut:?}").contains("foo")); // Debug
drop(refcell_refmut);
let refcell_ref = refcell.borrow();
assert_eq!(format!("{refcell_ref}"), "foo"); // Display
assert!(format!("{refcell_ref:?}").contains("foo")); // Debug
drop(refcell_ref);
}
#[test]
fn double_imm_borrow() {
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let x = RefCell::new(0);
let _b1 = x.borrow();
x.borrow();
}
#[test]
fn no_mut_then_imm_borrow() {
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let x = RefCell::new(0);
let _b1 = x.borrow_mut();
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assert!(x.try_borrow().is_err());
}
#[test]
fn no_imm_then_borrow_mut() {
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let x = RefCell::new(0);
let _b1 = x.borrow();
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assert!(x.try_borrow_mut().is_err());
}
#[test]
fn no_double_borrow_mut() {
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let x = RefCell::new(0);
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assert!(x.try_borrow().is_ok());
let _b1 = x.borrow_mut();
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assert!(x.try_borrow().is_err());
}
#[test]
fn imm_release_borrow_mut() {
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let x = RefCell::new(0);
{
let _b1 = x.borrow();
}
x.borrow_mut();
}
#[test]
fn mut_release_borrow_mut() {
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let x = RefCell::new(0);
{
let _b1 = x.borrow_mut();
}
x.borrow();
}
#[test]
fn double_borrow_single_release_no_borrow_mut() {
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let x = RefCell::new(0);
let _b1 = x.borrow();
{
let _b2 = x.borrow();
}
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
}
#[test]
#[should_panic]
fn discard_doesnt_unborrow() {
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let x = RefCell::new(0);
let _b = x.borrow();
let _ = _b;
let _b = x.borrow_mut();
}
#[test]
fn ref_clone_updates_flag() {
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let x = RefCell::new(0);
{
let b1 = x.borrow();
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
{
let _b2 = Ref::clone(&b1);
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
}
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
}
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
}
#[test]
fn ref_map_does_not_update_flag() {
let x = RefCell::new(Some(5));
{
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let b1: Ref<'_, Option<u32>> = x.borrow();
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
{
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let b2: Ref<'_, u32> = Ref::map(b1, |o| o.as_ref().unwrap());
assert_eq!(*b2, 5);
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
}
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
}
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assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
}
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#[test]
fn ref_map_split_updates_flag() {
let x = RefCell::new([1, 2]);
{
let b1 = x.borrow();
assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
{
let (_b2, _b3) = Ref::map_split(b1, |slc| slc.split_at(1));
assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_err());
}
assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
}
assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
{
let b1 = x.borrow_mut();
assert!(x.try_borrow().is_err());
assert!(x.try_borrow_mut().is_err());
{
let (_b2, _b3) = RefMut::map_split(b1, |slc| slc.split_at_mut(1));
assert!(x.try_borrow().is_err());
assert!(x.try_borrow_mut().is_err());
drop(_b2);
assert!(x.try_borrow().is_err());
assert!(x.try_borrow_mut().is_err());
}
assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
}
assert!(x.try_borrow().is_ok());
assert!(x.try_borrow_mut().is_ok());
}
#[test]
fn ref_map_split() {
let x = RefCell::new([1, 2]);
let (b1, b2) = Ref::map_split(x.borrow(), |slc| slc.split_at(1));
assert_eq!(*b1, [1]);
assert_eq!(*b2, [2]);
}
#[test]
fn ref_mut_map_split() {
let x = RefCell::new([1, 2]);
{
let (mut b1, mut b2) = RefMut::map_split(x.borrow_mut(), |slc| slc.split_at_mut(1));
assert_eq!(*b1, [1]);
assert_eq!(*b2, [2]);
b1[0] = 2;
b2[0] = 1;
}
assert_eq!(*x.borrow(), [2, 1]);
}
#[test]
fn ref_map_accessor() {
struct X(RefCell<(u32, char)>);
impl X {
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fn accessor(&self) -> Ref<'_, u32> {
Ref::map(self.0.borrow(), |tuple| &tuple.0)
}
}
let x = X(RefCell::new((7, 'z')));
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let d: Ref<'_, u32> = x.accessor();
assert_eq!(*d, 7);
}
#[test]
fn ref_mut_map_accessor() {
struct X(RefCell<(u32, char)>);
impl X {
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fn accessor(&self) -> RefMut<'_, u32> {
RefMut::map(self.0.borrow_mut(), |tuple| &mut tuple.0)
}
}
let x = X(RefCell::new((7, 'z')));
{
let mut d: RefMut<'_, u32> = x.accessor();
assert_eq!(*d, 7);
*d += 1;
}
assert_eq!(*x.0.borrow(), (8, 'z'));
}
#[test]
fn as_ptr() {
let c1: Cell<usize> = Cell::new(0);
c1.set(1);
assert_eq!(1, unsafe { *c1.as_ptr() });
let c2: Cell<usize> = Cell::new(0);
unsafe {
*c2.as_ptr() = 1;
}
assert_eq!(1, c2.get());
let r1: RefCell<usize> = RefCell::new(0);
*r1.borrow_mut() = 1;
assert_eq!(1, unsafe { *r1.as_ptr() });
let r2: RefCell<usize> = RefCell::new(0);
unsafe {
*r2.as_ptr() = 1;
}
assert_eq!(1, *r2.borrow());
}
#[test]
fn cell_default() {
let cell: Cell<u32> = Default::default();
assert_eq!(0, cell.get());
}
#[test]
fn cell_set() {
let cell = Cell::new(10);
cell.set(20);
assert_eq!(20, cell.get());
let cell = Cell::new("Hello".to_owned());
cell.set("World".to_owned());
assert_eq!("World".to_owned(), cell.into_inner());
}
#[test]
fn cell_replace() {
let cell = Cell::new(10);
assert_eq!(10, cell.replace(20));
assert_eq!(20, cell.get());
let cell = Cell::new("Hello".to_owned());
assert_eq!("Hello".to_owned(), cell.replace("World".to_owned()));
assert_eq!("World".to_owned(), cell.into_inner());
}
#[test]
fn cell_into_inner() {
let cell = Cell::new(10);
assert_eq!(10, cell.into_inner());
let cell = Cell::new("Hello world".to_owned());
assert_eq!("Hello world".to_owned(), cell.into_inner());
}
#[test]
fn cell_exterior() {
#[derive(Copy, Clone)]
#[allow(dead_code)]
struct Point {
x: isize,
y: isize,
z: isize,
}
fn f(p: &Cell<Point>) {
assert_eq!(p.get().z, 12);
p.set(Point { x: 10, y: 11, z: 13 });
assert_eq!(p.get().z, 13);
}
let a = Point { x: 10, y: 11, z: 12 };
let b = &Cell::new(a);
assert_eq!(b.get().z, 12);
f(b);
assert_eq!(a.z, 12);
assert_eq!(b.get().z, 13);
}
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#[test]
fn cell_does_not_clone() {
#[derive(Copy)]
#[allow(dead_code)]
struct Foo {
x: isize,
}
impl Clone for Foo {
fn clone(&self) -> Foo {
// Using Cell in any way should never cause clone() to be
// invoked -- after all, that would permit evil user code to
// abuse `Cell` and trigger crashes.
panic!();
}
}
let x = Cell::new(Foo { x: 22 });
let _y = x.get();
let _z = x.clone();
}
#[test]
fn refcell_default() {
let cell: RefCell<u64> = Default::default();
assert_eq!(0, *cell.borrow());
}
#[test]
fn unsafe_cell_unsized() {
let cell: &UnsafeCell<[i32]> = &UnsafeCell::new([1, 2, 3]);
{
let val: &mut [i32] = unsafe { &mut *cell.get() };
val[0] = 4;
val[2] = 5;
}
let comp: &mut [i32] = &mut [4, 2, 5];
assert_eq!(unsafe { &mut *cell.get() }, comp);
}
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#[test]
fn refcell_unsized() {
let cell: &RefCell<[i32]> = &RefCell::new([1, 2, 3]);
{
let b = &mut *cell.borrow_mut();
b[0] = 4;
b[2] = 5;
}
let comp: &mut [i32] = &mut [4, 2, 5];
assert_eq!(&*cell.borrow(), comp);
}
#[test]
fn refcell_ref_coercion() {
let cell: RefCell<[i32; 3]> = RefCell::new([1, 2, 3]);
{
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let mut cellref: RefMut<'_, [i32; 3]> = cell.borrow_mut();
cellref[0] = 4;
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let mut coerced: RefMut<'_, [i32]> = cellref;
coerced[2] = 5;
}
{
let comp: &mut [i32] = &mut [4, 2, 5];
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let cellref: Ref<'_, [i32; 3]> = cell.borrow();
assert_eq!(&*cellref, comp);
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let coerced: Ref<'_, [i32]> = cellref;
assert_eq!(&*coerced, comp);
}
}
#[test]
#[should_panic]
fn refcell_swap_borrows() {
let x = RefCell::new(0);
let _b = x.borrow();
let y = RefCell::new(1);
x.swap(&y);
}
#[test]
#[should_panic]
fn refcell_replace_borrows() {
let x = RefCell::new(0);
let _b = x.borrow();
x.replace(1);
}
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#[test]
fn refcell_format() {
let name = RefCell::new("rust");
let what = RefCell::new("rocks");
let msg = format!("{name} {}", &*what.borrow(), name = &*name.borrow());
assert_eq!(msg, "rust rocks".to_string());
}
#[allow(dead_code)]
fn const_cells() {
const UNSAFE_CELL: UnsafeCell<i32> = UnsafeCell::new(3);
const _: i32 = UNSAFE_CELL.into_inner();
const REF_CELL: RefCell<i32> = RefCell::new(3);
const _: i32 = REF_CELL.into_inner();
const CELL: Cell<i32> = Cell::new(3);
const _: i32 = CELL.into_inner();
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/* FIXME(#110395)
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const UNSAFE_CELL_FROM: UnsafeCell<i32> = UnsafeCell::from(3);
const _: i32 = UNSAFE_CELL.into_inner();
const REF_CELL_FROM: RefCell<i32> = RefCell::from(3);
const _: i32 = REF_CELL.into_inner();
const CELL_FROM: Cell<i32> = Cell::from(3);
const _: i32 = CELL.into_inner();
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*/
}