Struct toks::prelude::RefCell

pub struct RefCell<T> where
    T: ?Sized,  { /* fields omitted */ }

A mutable memory location with dynamically checked borrow rules

See the module-level documentation for more.

Methods

impl<T> RefCell<T>

const fn new(value: T) -> RefCell<T>

Creates a new RefCell containing value.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

fn into_inner(self) -> T

Consumes the RefCell, returning the wrapped value.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

let five = c.into_inner();

fn replace(&self, t: T) -> T

🔬 This is a nightly-only experimental API. (refcell_replace_swap)

Replaces the wrapped value with a new one, returning the old value, without deinitializing either one.

This function corresponds to std::mem::replace.

Examples

#![feature(refcell_replace_swap)]
use std::cell::RefCell;
let c = RefCell::new(5);
let u = c.replace(6);
assert_eq!(u, 5);
assert_eq!(c, RefCell::new(6));

Panics

This function will panic if the RefCell has any outstanding borrows, whether or not they are full mutable borrows.

fn swap(&self, other: &RefCell<T>)

🔬 This is a nightly-only experimental API. (refcell_replace_swap)

Swaps the wrapped value of self with the wrapped value of other, without deinitializing either one.

This function corresponds to std::mem::swap.

Examples

#![feature(refcell_replace_swap)]
use std::cell::RefCell;
let c = RefCell::new(5);
let d = RefCell::new(6);
c.swap(&d);
assert_eq!(c, RefCell::new(6));
assert_eq!(d, RefCell::new(5));

Panics

This function will panic if either RefCell has any outstanding borrows, whether or not they are full mutable borrows.

impl<T> RefCell<T> where
    T: ?Sized, 

fn borrow(&self) -> Ref<T>

Immutably borrows the wrapped value.

The borrow lasts until the returned Ref exits scope. Multiple immutable borrows can be taken out at the same time.

Panics

Panics if the value is currently mutably borrowed. For a non-panicking variant, use try_borrow.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

let borrowed_five = c.borrow();
let borrowed_five2 = c.borrow();

An example of panic:

use std::cell::RefCell;
use std::thread;

let result = thread::spawn(move || {
   let c = RefCell::new(5);
   let m = c.borrow_mut();

   let b = c.borrow(); // this causes a panic
}).join();

assert!(result.is_err());

fn try_borrow(&self) -> Result<Ref<T>, BorrowError>

Immutably borrows the wrapped value, returning an error if the value is currently mutably borrowed.

The borrow lasts until the returned Ref exits scope. Multiple immutable borrows can be taken out at the same time.

This is the non-panicking variant of borrow.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

{
    let m = c.borrow_mut();
    assert!(c.try_borrow().is_err());
}

{
    let m = c.borrow();
    assert!(c.try_borrow().is_ok());
}

fn borrow_mut(&self) -> RefMut<T>

Mutably borrows the wrapped value.

The borrow lasts until the returned RefMut exits scope. The value cannot be borrowed while this borrow is active.

Panics

Panics if the value is currently borrowed. For a non-panicking variant, use try_borrow_mut.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

*c.borrow_mut() = 7;

assert_eq!(*c.borrow(), 7);

An example of panic:

use std::cell::RefCell;
use std::thread;

let result = thread::spawn(move || {
   let c = RefCell::new(5);
   let m = c.borrow();

   let b = c.borrow_mut(); // this causes a panic
}).join();

assert!(result.is_err());

fn try_borrow_mut(&self) -> Result<RefMut<T>, BorrowMutError>

Mutably borrows the wrapped value, returning an error if the value is currently borrowed.

The borrow lasts until the returned RefMut exits scope. The value cannot be borrowed while this borrow is active.

This is the non-panicking variant of borrow_mut.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

{
    let m = c.borrow();
    assert!(c.try_borrow_mut().is_err());
}

assert!(c.try_borrow_mut().is_ok());

fn as_ptr(&self) -> *mut T

Returns a raw pointer to the underlying data in this cell.

Examples

use std::cell::RefCell;

let c = RefCell::new(5);

let ptr = c.as_ptr();

fn get_mut(&mut self) -> &mut T

Returns a mutable reference to the underlying data.

This call borrows RefCell mutably (at compile-time) so there is no need for dynamic checks.

However be cautious: this method expects self to be mutable, which is generally not the case when using a RefCell. Take a look at the borrow_mut method instead if self isn't mutable.

Also, please be aware that this method is only for special circumstances and is usually not what you want. In case of doubt, use borrow_mut instead.

Examples

use std::cell::RefCell;

let mut c = RefCell::new(5);
*c.get_mut() += 1;

assert_eq!(c, RefCell::new(6));

Trait Implementations

impl<'de, T> Deserialize<'de> for RefCell<T> where
    T: Deserialize<'de>, 

fn deserialize<D>(
    deserializer: D
) -> Result<RefCell<T>, <D as Deserializer<'de>>::Error> where
    D: Deserializer<'de>, 

impl<T> Serialize for RefCell<T> where
    T: Serialize, 

fn serialize<S>(
    &self,
    serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
    S: Serializer, 

impl<T> From<T> for RefCell<T>

fn from(t: T) -> RefCell<T>

impl<T> Debug for RefCell<T> where
    T: Debug + ?Sized, 

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

impl<T> Default for RefCell<T> where
    T: Default, 

fn default() -> RefCell<T>

Creates a RefCell<T>, with the Default value for T.

impl<T> Clone for RefCell<T> where
    T: Clone, 

fn clone(&self) -> RefCell<T>

impl<T> PartialOrd<RefCell<T>> for RefCell<T> where
    T: PartialOrd<T> + ?Sized, 

fn partial_cmp(&self, other: &RefCell<T>) -> Option<Ordering>

fn lt(&self, other: &RefCell<T>) -> bool

fn le(&self, other: &RefCell<T>) -> bool

fn gt(&self, other: &RefCell<T>) -> bool

fn ge(&self, other: &RefCell<T>) -> bool

impl<T> Eq for RefCell<T> where
    T: Eq + ?Sized, 

impl<T> Send for RefCell<T> where
    T: Send + ?Sized, 

impl<T, U> CoerceUnsized<RefCell<U>> for RefCell<T> where
    T: CoerceUnsized<U>, 

impl<T> !Sync for RefCell<T> where
    T: ?Sized, 

impl<T> Ord for RefCell<T> where
    T: Ord + ?Sized, 

fn cmp(&self, other: &RefCell<T>) -> Ordering

impl<T> PartialEq<RefCell<T>> for RefCell<T> where
    T: PartialEq<T> + ?Sized, 

fn eq(&self, other: &RefCell<T>) -> bool