Struct rustc_data_structures::sync::LockGuard

pub struct LockGuard<'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,

pub 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.

Examples

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<'a, T> Display for RefMut<'a, T> where     T: Display + ?Sized,

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

Formats the value using the given formatter.

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

Important traits for &'a mut R

impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

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

Mutably dereferences the value.

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

type Target = T

The resulting type after dereferencing.

Important traits for &'a mut R

impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn deref(&self) -> &T

Dereferences the value.

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

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

Formats the value using the given formatter.

impl<'a, T> StableDeref for RefMut<'a, T> where     T: ?Sized,