Struct std::cell::RefMut 1.0.0[−][src]
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.
Implementations
impl<'b, T> RefMut<'b, T> where
T: ?Sized, [src]
impl<'b, T> RefMut<'b, T> where
T: ?Sized, [src]pub fn map<U, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized, 1.8.0[src]
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
Makes 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'));Run
pub fn filter_map<U, F>(
orig: RefMut<'b, T>,
f: F
) -> Result<RefMut<'b, U>, RefMut<'b, T>> where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized, [src]
orig: RefMut<'b, T>,
f: F
) -> Result<RefMut<'b, U>, RefMut<'b, T>> where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
🔬 This is a nightly-only experimental API. (cell_filter_map #81061)
recently added
Makes a new RefMut for an optional component of the borrowed data. The
original guard is returned as an Err(..) if the closure returns
None.
The RefCell is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as
RefMut::filter_map(...). A method would interfere with methods of the
same name on the contents of a RefCell used through Deref.
Examples
#![feature(cell_filter_map)] use std::cell::{RefCell, RefMut}; let c = RefCell::new(vec![1, 2, 3]); { let b1: RefMut<Vec<u32>> = c.borrow_mut(); let mut b2: Result<RefMut<u32>, _> = RefMut::filter_map(b1, |v| v.get_mut(1)); if let Ok(mut b2) = b2 { *b2 += 2; } } assert_eq!(*c.borrow(), vec![1, 4, 3]);Run
pub fn map_split<U, V, F>(
orig: RefMut<'b, T>,
f: F
) -> (RefMut<'b, U>, RefMut<'b, V>) where
F: FnOnce(&mut T) -> (&mut U, &mut V),
V: ?Sized,
U: ?Sized, 1.35.0[src]
orig: RefMut<'b, T>,
f: F
) -> (RefMut<'b, U>, RefMut<'b, V>) where
F: FnOnce(&mut T) -> (&mut U, &mut V),
V: ?Sized,
U: ?Sized,
Splits a RefMut into multiple RefMuts for different components of the
borrowed data.
The underlying RefCell will remain mutably borrowed until both
returned RefMuts go out of scope.
The RefCell is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as
RefMut::map_split(...). 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 cell = RefCell::new([1, 2, 3, 4]); let borrow = cell.borrow_mut(); let (mut begin, mut end) = RefMut::map_split(borrow, |slice| slice.split_at_mut(2)); assert_eq!(*begin, [1, 2]); assert_eq!(*end, [3, 4]); begin.copy_from_slice(&[4, 3]); end.copy_from_slice(&[2, 1]);Run
pub fn leak(orig: RefMut<'b, T>) -> &'b mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut W[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut WConvert into a mutable reference to the underlying data.
The underlying RefCell can not be borrowed from again and will always appear already
mutably borrowed, making the returned reference the only to the interior.
This is an associated function that needs to be used as
RefMut::leak(...). A method would interfere with methods of the
same name on the contents of a RefCell used through Deref.
Examples
#![feature(cell_leak)] use std::cell::{RefCell, RefMut}; let cell = RefCell::new(0); let value = RefMut::leak(cell.borrow_mut()); assert_eq!(*value, 0); *value = 1; assert!(cell.try_borrow_mut().is_err());Run
Trait Implementations
impl<'_, T> Deref for RefMut<'_, T> where
T: ?Sized, [src]
impl<'_, T> Deref for RefMut<'_, T> where
T: ?Sized, [src]type Target = T
The resulting type after dereferencing.
pub fn deref(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut W[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut Wimpl<'_, T> DerefMut for RefMut<'_, T> where
T: ?Sized, [src]
impl<'_, T> DerefMut for RefMut<'_, T> where
T: ?Sized, [src]pub fn deref_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut W[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut Wimpl<'b, T, U> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> where
T: Unsize<U> + ?Sized,
U: ?Sized, [src]
T: Unsize<U> + ?Sized,
U: ?Sized,
Auto Trait Implementations
impl<'b, T> !RefUnwindSafe for RefMut<'b, T>
impl<'b, T> !Send for RefMut<'b, T>
impl<'b, T> !Sync for RefMut<'b, T>
impl<'b, T: ?Sized> Unpin for RefMut<'b, T>
impl<'b, T> !UnwindSafe for RefMut<'b, T>
Blanket Implementations
impl<T> Borrow<T> for T where
T: ?Sized, [src]
impl<T> Borrow<T> for T where
T: ?Sized, [src]pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut W[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut Wimpl<T> BorrowMut<T> for T where
T: ?Sized, [src]
impl<T> BorrowMut<T> for T where
T: ?Sized, [src]pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut W[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?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 Rimpl<W: Write + ?Sized> Write for &mut W