Struct thread_isolated::RefMut

pub struct RefMut<'b, T> where
    T: 'b + ?Sized,  { /* fields omitted */ }

A wrapper type for a mutably borrowed value from a RefCell<T>.

See the module-level documentation for more.

Methods

impl<'b, T> RefMut<'b, T> where
    T: ?Sized, 

fn map<U, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where
    F: FnOnce(&mut T) -> &mut U,
    U: ?Sized, 

Make a new RefMut for a component of the borrowed data, e.g. an enum variant.

The RefCell is already mutably borrowed, so this cannot fail.

This is an associated function that needs to be used as RefMut::map(...). A method would interfere with methods of the same name on the contents of a RefCell used through Deref.

Example

use std::cell::{RefCell, RefMut};

let c = RefCell::new((5, 'b'));
{
    let b1: RefMut<(u32, char)> = c.borrow_mut();
    let mut b2: RefMut<u32> = RefMut::map(b1, |t| &mut t.0);
    assert_eq!(*b2, 5);
    *b2 = 42;
}
assert_eq!(*c.borrow(), (42, 'b'));

Trait Implementations

impl<'b, T, U> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> where
    T: Unsize<U> + ?Sized,
    U: ?Sized, 

impl<'b, T> DerefMut for RefMut<'b, T> where
    T: ?Sized, 

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

impl<'b, T> Deref for RefMut<'b, T> where
    T: ?Sized, 

type Target = T

fn deref(&self) -> &T

impl<'b, T> Debug for RefMut<'b, T> where
    T: Debug + ?Sized, 

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