1.0.0[][src]Struct rustc_data_structures::sync::MappedReadGuard

pub struct MappedReadGuard<'b, T> where
    T: 'b + 'b + ?Sized
{ value: &'b T, borrow: BorrowRef<'b>, }

Wraps a borrowed reference to a value in a RefCell box. A wrapper type for an immutably borrowed value from a RefCell<T>.

See the module-level documentation for more.

Fields

Methods

impl<'b, T> Ref<'b, T> where
    T: ?Sized
[src]

Copies a Ref.

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

This is an associated function that needs to be used as Ref::clone(...). A Clone implementation or a method would interfere with the widespread use of r.borrow().clone() to clone the contents of a RefCell.

Make a new Ref for a component of the borrowed data.

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

This is an associated function that needs to be used as Ref::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, Ref};

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

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

Split a Ref into multiple Refs for different components of the borrowed data.

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

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

Examples

#![feature(refcell_map_split)]
use std::cell::{Ref, RefCell};

let cell = RefCell::new([1, 2, 3, 4]);
let borrow = cell.borrow();
let (begin, end) = Ref::map_split(borrow, |slice| slice.split_at(2));
assert_eq!(*begin, [1, 2]);
assert_eq!(*end, [3, 4]);

Trait Implementations

impl<'b, T> Debug for Ref<'b, T> where
    T: Debug + ?Sized
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Formats the value using the given formatter. Read more

impl<'b, T, U> CoerceUnsized<Ref<'b, U>> for Ref<'b, T> where
    T: Unsize<U> + ?Sized,
    U: ?Sized
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impl<'b, T> Deref for Ref<'b, T> where
    T: ?Sized
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The resulting type after dereferencing.

Important traits for &'a mut R

Dereferences the value.

impl<'a, T> Display for Ref<'a, T> where
    T: Display + ?Sized
1.20.0
[src]

Formats the value using the given formatter. Read more

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

Auto Trait Implementations

impl<'b, T> !Send for Ref<'b, T>

impl<'b, T> !Sync for Ref<'b, T>

Blanket Implementations

impl<T> Erased for T
[src]

impl<T> Send for T where
    T: ?Sized
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impl<T> Sync for T where
    T: ?Sized
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impl<T> From for T
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Performs the conversion.

impl<T> ToString for T where
    T: Display + ?Sized
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Converts the given value to a String. Read more

impl<T, U> Into for T where
    U: From<T>, 
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Performs the conversion.

impl<T, U> TryFrom for T where
    T: From<U>, 
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🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

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

Performs the conversion.

impl<T> Borrow for T where
    T: ?Sized
[src]

Important traits for &'a mut R

Immutably borrows from an owned value. Read more

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
[src]

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

The type returned in the event of a conversion error.

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

Performs the conversion.

impl<T> BorrowMut for T where
    T: ?Sized
[src]

Important traits for &'a mut R

Mutably borrows from an owned value. Read more

impl<T> Any for T where
    T: 'static + ?Sized
[src]

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

this method will likely be replaced by an associated static

Gets the TypeId of self. Read more

impl<E> SpecializationError for E
[src]

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

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Create an error for a missing method specialization. Defaults to panicking with type, trait & method names. S is the encoder/decoder state type, T is the type being encoded/decoded, and the arguments are the names of the trait and method that should've been overridden. Read more

impl<T> Erased for T