Struct elysees::ArcBox

#[repr(transparent)]pub struct ArcBox<T: ?Sized>(_);

An Arc that is known to be uniquely owned

When Arcs are constructed, they are known to be uniquely owned. In such a case it is safe to mutate the contents of the Arc. Normally, one would just handle this by mutating the data on the stack before allocating the Arc, however it's possible the data is large or unsized and you need to heap-allocate it earlier in such a way that it can be freely converted into a regular Arc once you're done.

ArcBox exists for this purpose, when constructed it performs the same allocations necessary for an Arc, however it allows mutable access. Once the mutation is finished, you can call .shareable() and get a regular Arc out of it. You can also attempt to cast an Arc back into a ArcBox, which will succeed if the Arc is unique

let data = [1, 2, 3, 4, 5];
let mut x = ArcBox::new(data);
let x_ptr = x.deref() as *const _;

x[4] = 7; // mutate!

// The allocation has been modified, but not moved
assert_eq!(x.deref(), &[1, 2, 3, 4, 7]);
assert_eq!(x_ptr, x.deref() as *const _);

let y = x.shareable(); // y is an Arc<T>

// The allocation has not been modified or moved
assert_eq!(y.deref(), &[1, 2, 3, 4, 7]);
assert_eq!(x_ptr, y.deref() as *const _);

Implementations

impl<T> ArcBox<T>

pub fn new(data: T) -> Self

Construct a new ArcBox

impl<T: ?Sized> ArcBox<T>

pub fn shareable(self) -> Arc<T>

Convert to a shareable Arc once we're done mutating it

Trait Implementations

impl<S: ?Sized + SliceDst> AllocSliceDst<S> for ArcBox<S>

unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self where
    I: FnOnce(NonNull<S>), 

Create a new custom slice DST.

impl<T: ?Sized> AsMut<T> for ArcBox<T>

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

Performs the conversion.

impl<T: ?Sized> AsRef<*const T> for ArcBox<T>

fn as_ref(&self) -> &*const T

Performs the conversion.

impl<T: ?Sized> AsRef<*mut T> for ArcBox<T>

fn as_ref(&self) -> &*mut T

Performs the conversion.

impl<T: ?Sized> AsRef<NonNull<T>> for ArcBox<T>

fn as_ref(&self) -> &NonNull<T>

Performs the conversion.

impl<T: ?Sized> AsRef<T> for ArcBox<T>

fn as_ref(&self) -> &T

Performs the conversion.

impl<T: ?Sized> Borrow<T> for ArcBox<T>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T: ?Sized> BorrowMut<T> for ArcBox<T>

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

Mutably borrows from an owned value.

impl<T: Clone> Clone for ArcBox<T>

fn clone(&self) -> ArcBox<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug + ?Sized> Debug for ArcBox<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for ArcBox<T>

fn default() -> ArcBox<T>

Returns the "default value" for a type.

impl<T: ?Sized> Deref for ArcBox<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T: ?Sized> DerefMut for ArcBox<T>

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

Mutably dereferences the value.

impl<T: Eq + ?Sized> Eq for ArcBox<T>

impl<T: ?Sized + Erasable> ErasablePtr for ArcBox<T>

fn erase(this: Self) -> ErasedPtr

Turn this erasable pointer into an erased pointer.

unsafe fn unerase(this: ErasedPtr) -> Self

Unerase this erased pointer.

impl<T: Hash + ?Sized> Hash for ArcBox<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl<T: Ord + ?Sized> Ord for ArcBox<T>

fn cmp(&self, other: &ArcBox<T>) -> Ordering

This method returns an Ordering between self and other.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

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

Restrict a value to a certain interval.

impl<T: PartialEq + ?Sized> PartialEq<ArcBox<T>> for ArcBox<T>

fn eq(&self, other: &ArcBox<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &ArcBox<T>) -> bool

This method tests for !=.

impl<T: PartialOrd + ?Sized> PartialOrd<ArcBox<T>> for ArcBox<T>

fn partial_cmp(&self, other: &ArcBox<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &ArcBox<T>) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &ArcBox<T>) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &ArcBox<T>) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &ArcBox<T>) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: ?Sized> StableDeref for ArcBox<T>

impl<T> Stowable for ArcBox<T>

impl<T: ?Sized> StructuralEq for ArcBox<T>

impl<T: ?Sized> StructuralPartialEq for ArcBox<T>

impl<S: ?Sized + SliceDst> TryAllocSliceDst<S> for ArcBox<S>

unsafe fn try_new_slice_dst<I, E>(len: usize, init: I) -> Result<Self, E> where
    I: FnOnce(NonNull<S>) -> Result<(), E>, 

Create a new custom slice DST with a fallible initialization function.

impl<T: ?Sized> UnionAlign for ArcBox<T> where
    ArcBox<T>: ErasablePtr, 

fn left<B: UnionAlign>(this: Self) -> Union2<Self, B>

fn right<A: UnionAlign>(this: Self) -> Union2<A, Self>

fn a<B: UnionAlign, C: UnionAlign, D: UnionAlign>(
    this: Self
) -> Union4<Self, B, C, D>

fn b<A: UnionAlign, C: UnionAlign, D: UnionAlign>(
    this: Self
) -> Union4<A, Self, C, D>

fn c<A: UnionAlign, B: UnionAlign, D: UnionAlign>(
    this: Self
) -> Union4<A, B, Self, D>

fn d<A: UnionAlign, B: UnionAlign, C: UnionAlign>(
    this: Self
) -> Union4<A, B, C, Self>