#[repr(transparent)]pub struct Cell<T> where T: ?Sized, { /* fields omitted */ }
A mutable memory location.
In this example, you can see that Cell<T> enables mutation inside an immutable struct. In other words, it enables "interior mutability".
use std::cell::Cell;
struct SomeStruct {
regular_field: u8,
special_field: Cell<u8>,
}
let my_struct = SomeStruct {
regular_field: 0,
special_field: Cell::new(1),
};
let new_value = 100;
// ERROR: `my_struct` is immutable
// my_struct.regular_field = new_value;
// WORKS: although `my_struct` is immutable, `special_field` is a `Cell`,
// which can always be mutated
my_struct.special_field.set(new_value);
assert_eq!(my_struct.special_field.get(), new_value);See the module-level documentation for more.
impl<T> Cell<T>[src]
pub const fn new(value: T) -> Cell<T>[src]
Creates a new Cell containing the given value.
use std::cell::Cell; let c = Cell::new(5);
pub fn set(&self, val: T)[src]
Sets the contained value.
use std::cell::Cell; let c = Cell::new(5); c.set(10);
pub fn swap(&self, other: &Cell<T>)[src]1.17.0
Swaps the values of two Cells. Difference with std::mem::swap is that this function doesn't require &mut reference.
use std::cell::Cell; let c1 = Cell::new(5i32); let c2 = Cell::new(10i32); c1.swap(&c2); assert_eq!(10, c1.get()); assert_eq!(5, c2.get());
pub fn replace(&self, val: T) -> T[src]1.17.0
Replaces the contained value, and returns it.
use std::cell::Cell; let cell = Cell::new(5); assert_eq!(cell.get(), 5); assert_eq!(cell.replace(10), 5); assert_eq!(cell.get(), 10);
pub fn into_inner(self) -> T[src]1.17.0
Unwraps the value.
use std::cell::Cell; let c = Cell::new(5); let five = c.into_inner(); assert_eq!(five, 5);
impl<T> Cell<T> where
T: Copy, [src]
pub fn get(&self) -> T[src]
Returns a copy of the contained value.
use std::cell::Cell; let c = Cell::new(5); let five = c.get();
pub fn update<F>(&self, f: F) -> T where
F: FnOnce(T) -> T, [src]
Updates the contained value using a function and returns the new value.
#![feature(cell_update)] use std::cell::Cell; let c = Cell::new(5); let new = c.update(|x| x + 1); assert_eq!(new, 6); assert_eq!(c.get(), 6);
impl<T> Cell<T> where
T: ?Sized, [src]
pub const fn as_ptr(&self) -> *mut T[src]1.12.0
Returns a raw pointer to the underlying data in this cell.
use std::cell::Cell; let c = Cell::new(5); let ptr = c.as_ptr();
pub fn get_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized,
type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized,
type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W
[src]1.11.0
Returns a mutable reference to the underlying data.
This call borrows Cell mutably (at compile-time) which guarantees that we possess the only reference.
use std::cell::Cell; let mut c = Cell::new(5); *c.get_mut() += 1; assert_eq!(c.get(), 6);
pub fn from_mut(t: &mut T) -> &Cell<T>[src]1.37.0
Returns a &Cell<T> from a &mut T
use std::cell::Cell; let slice: &mut [i32] = &mut [1, 2, 3]; let cell_slice: &Cell<[i32]> = Cell::from_mut(slice); let slice_cell: &[Cell<i32>] = cell_slice.as_slice_of_cells(); assert_eq!(slice_cell.len(), 3);
impl<T> Cell<T> where
T: Default, [src]
pub fn take(&self) -> T[src]1.17.0
Takes the value of the cell, leaving Default::default() in its place.
use std::cell::Cell; let c = Cell::new(5); let five = c.take(); assert_eq!(five, 5); assert_eq!(c.into_inner(), 0);
impl<T> Cell<[T]>[src]
pub fn as_slice_of_cells(&self) -> &[Cell<T>]ⓘNotable traits for &'_ [u8]
impl<'_> Read for &'_ [u8]
impl<'_> Write for &'_ mut [u8]
[src]1.37.0
Returns a &[Cell<T>] from a &Cell<[T]>
use std::cell::Cell; let slice: &mut [i32] = &mut [1, 2, 3]; let cell_slice: &Cell<[i32]> = Cell::from_mut(slice); let slice_cell: &[Cell<i32>] = cell_slice.as_slice_of_cells(); assert_eq!(slice_cell.len(), 3);
impl<T> Clone for Cell<T> where
T: Copy, [src]
impl<T, U> CoerceUnsized<Cell<U>> for Cell<T> where
T: CoerceUnsized<U>, [src]
impl<T> Debug for Cell<T> where
T: Copy + Debug, [src]
impl<T> Default for Cell<T> where
T: Default, [src]
impl<T> Eq for Cell<T> where
T: Eq + Copy, [src]1.2.0
impl<T> From<T> for Cell<T>[src]1.12.0
impl<T> Ord for Cell<T> where
T: Ord + Copy, [src]1.10.0
fn cmp(&self, other: &Cell<T>) -> Ordering[src]
fn max(self, other: Self) -> Self[src]1.21.0
fn min(self, other: Self) -> Self[src]1.21.0
fn clamp(self, min: Self, max: Self) -> Self[src]
impl<T> PartialEq<Cell<T>> for Cell<T> where
T: PartialEq<T> + Copy, [src]
impl<T> PartialOrd<Cell<T>> for Cell<T> where
T: PartialOrd<T> + Copy, [src]1.10.0
fn partial_cmp(&self, other: &Cell<T>) -> Option<Ordering>[src]
fn lt(&self, other: &Cell<T>) -> bool[src]
fn le(&self, other: &Cell<T>) -> bool[src]
fn gt(&self, other: &Cell<T>) -> bool[src]
fn ge(&self, other: &Cell<T>) -> bool[src]
impl<T> Send for Cell<T> where
T: Send + ?Sized, [src]
impl<T> !Sync for Cell<T> where
T: ?Sized, [src]
impl<T> !RefUnwindSafe for Cell<T>impl<T: ?Sized> Unpin for Cell<T> where
T: Unpin, impl<T: ?Sized> UnwindSafe for Cell<T> where
T: UnwindSafe, impl<T> Any for T where
T: 'static + ?Sized, [src]
impl<T> Borrow<T> for T where
T: ?Sized, [src]
fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized,
type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized,
type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W
[src]
impl<T> BorrowMut<T> for T where
T: ?Sized, [src]
fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized,
type Output = <F as Future>::Output;
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized,
type Item = <I as Iterator>::Item;
impl<R: Read + ?Sized, '_> Read for &'_ mut R
impl<W: Write + ?Sized, '_> Write for &'_ mut W
[src]
impl<T> From<!> for T[src]
impl<T> From<T> for T[src]
impl<T, U> Into<U> for T where
U: From<T>, [src]
impl<T> ToOwned for T where
T: Clone, [src]
type Owned = TThe resulting type after obtaining ownership.
fn to_owned(&self) -> T[src]
fn clone_into(&self, target: &mut T)[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>, [src]
type Error = InfallibleThe type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>, [src]
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/cell/struct.Cell.html