Struct core::cell::RefCell 1.0.0
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pub struct RefCell<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>[src]
pub const fn new(value: T) -> RefCell<T>[src]
Creates a new RefCell containing value.
Examples
use std::cell::RefCell; let c = RefCell::new(5);Run
pub fn into_inner(self) -> T[src]
Consumes the RefCell, returning the wrapped value.
Examples
use std::cell::RefCell; let c = RefCell::new(5); let five = c.into_inner();Run
pub fn replace(&self, t: T) -> T1.24.0[src]
Replaces the wrapped value with a new one, returning the old value, without deinitializing either one.
This function corresponds to std::mem::replace.
Panics
Panics if the value is currently borrowed.
Examples
use std::cell::RefCell; let cell = RefCell::new(5); let old_value = cell.replace(6); assert_eq!(old_value, 5); assert_eq!(cell, RefCell::new(6));Run
pub fn replace_with<F: FnOnce(&mut T) -> T>(&self, f: F) -> T[src]
Replaces the wrapped value with a new one computed from f, returning
the old value, without deinitializing either one.
This function corresponds to std::mem::replace.
Panics
Panics if the value is currently borrowed.
Examples
#![feature(refcell_replace_swap)] use std::cell::RefCell; let cell = RefCell::new(5); let old_value = cell.replace_with(|&mut old| old + 1); assert_eq!(old_value, 5); assert_eq!(cell, RefCell::new(6));Run
pub fn swap(&self, other: &Self)1.24.0[src]
Swaps the wrapped value of self with the wrapped value of other,
without deinitializing either one.
This function corresponds to std::mem::swap.
Panics
Panics if the value in either RefCell is currently borrowed.
Examples
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));Run
impl<T: ?Sized> RefCell<T>[src]
pub fn borrow(&self) -> Ref<T>[src]
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();Run
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());Run
pub fn try_borrow(&self) -> Result<Ref<T>, BorrowError>1.13.0[src]
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()); }Run
pub fn borrow_mut(&self) -> RefMut<T>[src]
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);Run
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());Run
pub fn try_borrow_mut(&self) -> Result<RefMut<T>, BorrowMutError>1.13.0[src]
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());Run
pub fn as_ptr(&self) -> *mut T1.12.0[src]
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();Run
pub fn get_mut(&mut self) -> &mut T1.11.0[src]
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));Run
Trait Implementations
impl<T: ?Sized> Send for RefCell<T> where
T: Send, [src]
T: Send,
impl<T: ?Sized> !Sync for RefCell<T>[src]
impl<T: Clone> Clone for RefCell<T>[src]
fn clone(&self) -> RefCell<T>[src]
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)[src]
Performs copy-assignment from source. Read more
impl<T: Default> Default for RefCell<T>[src]
impl<T: ?Sized + PartialEq> PartialEq for RefCell<T>[src]
fn eq(&self, other: &RefCell<T>) -> bool[src]
This method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, other: &Rhs) -> bool[src]
This method tests for !=.
impl<T: ?Sized + Eq> Eq for RefCell<T>1.2.0[src]
impl<T: ?Sized + PartialOrd> PartialOrd for RefCell<T>1.10.0[src]
fn partial_cmp(&self, other: &RefCell<T>) -> Option<Ordering>[src]
This method returns an ordering between self and other values if one exists. Read more
fn lt(&self, other: &RefCell<T>) -> bool[src]
This method tests less than (for self and other) and is used by the < operator. Read more
fn le(&self, other: &RefCell<T>) -> bool[src]
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
fn gt(&self, other: &RefCell<T>) -> bool[src]
This method tests greater than (for self and other) and is used by the > operator. Read more
fn ge(&self, other: &RefCell<T>) -> bool[src]
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
impl<T: ?Sized + Ord> Ord for RefCell<T>1.10.0[src]
fn cmp(&self, other: &RefCell<T>) -> Ordering[src]
This method returns an Ordering between self and other. Read more
fn max(self, other: Self) -> Self where
Self: Sized, 1.21.0[src]
Self: Sized,
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self where
Self: Sized, 1.21.0[src]
Self: Sized,
Compares and returns the minimum of two values. Read more