Struct ArcUnion 

pub struct ArcUnion<A, B> { /* private fields */ }

A tagged union that can represent Arc<A> or Arc<B> while only consuming a single word. The type is also NonNull, and thus can be stored in an Option without increasing size.

This is functionally equivalent to enum ArcUnion<A, B> { First(Arc<A>), Second(Arc<B>) but only takes up up a single word of stack space.

This could probably be extended to support four types if necessary.

Implementations

impl<A, B> ArcUnion<A, B>

pub fn ptr_eq(this: &Self, other: &Self) -> bool

Returns true if the two values are pointer-equal.

pub fn strong_count(this: &Self) -> usize

Reference count.

pub fn borrow(&self) -> ArcUnionBorrow<'_, A, B>

Returns an enum representing a borrow of either A or B.

pub fn from_first(other: Arc<A>) -> Self

Creates an ArcUnion from an instance of the first type.

pub fn from_second(other: Arc<B>) -> Self

Creates an ArcUnion from an instance of the second type.

pub fn is_first(&self) -> bool

Returns true if this ArcUnion contains the first type.

pub fn is_second(&self) -> bool

Returns true if this ArcUnion contains the second type.

pub fn as_first(&self) -> Option<ArcBorrow<'_, A>>

Returns a borrow of the first type if applicable, otherwise None.

pub fn as_second(&self) -> Option<ArcBorrow<'_, B>>

Returns a borrow of the second type if applicable, otherwise None.

Trait Implementations

impl<A, B> Clone for ArcUnion<A, B>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<A: Debug, B: Debug> Debug for ArcUnion<A, B>

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

Formats the value using the given formatter.

impl<A, B> Drop for ArcUnion<A, B>

fn drop(&mut self)

Executes the destructor for this type.

impl<A: PartialEq, B: PartialEq> PartialEq for ArcUnion<A, B>

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<A: Sync + Send, B: Send + Sync> Send for ArcUnion<A, B>

impl<A: Sync + Send, B: Send + Sync> Sync for ArcUnion<A, B>

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes