Trait IndependentClone

Source

pub trait IndependentClone<S: Speed>: Sized {
    // Required method
    fn independent_clone(&self) -> Self;
}

Expand description

Get deep clones of a value, which do not share any semantically-important mutable state.

The goal is that the independent clone and its source appear to act completely independently, at least from their public interfaces; mutating or dropping one clone (among possible actions) should have no potentially-observable effect on any other independent clone.

Note also that an independent clone and its source may reference the same immutable data, even if the public interface of the type could be used to confirm that two independent clones are (or were) associated. (However, there should not be a way for either the source or any independent clone to affect that data’s value or address in memory.)

Side-channel attacks should be ignored in implementing this trait. The point is to provide deep clones, not cryptographic-quality guarantees about how those deep clones are performed.

§Exceptions

A type implementing IndependentClone may specify that certain methods or accesses are not subject to these guarantees.
Debug should be assumed to be an exception. Intentionally worsening the life of someone debugging your type is not a goal.
Shared mutable data which is written to but never read, or is read with effects that can only be publicly observed through exceptions, is acceptable.

§Other edge cases

A user calling as_ptr() and friends on references, to do address comparisons: if the address returned could change, then even if the underlying value at a new address would be the same, “the address of the data” should be considered mutable state. If that mutable state can be affected by the actions of the source of the independent clone or by other clones, then the address of the data must not be publicly exposed by the type’s interface.
Copy-on-write data: while likely permissible if properly encapsulated, presumably the source, the independent clone, or both are going to be mutated; it’d be best to give the independent clone a unique owned copy of the data. Further, if some sort of reference-counted copy-on-write scheme is used where the last clone to refer to the data doesn’t need to copy it, then the reference count used to determine that is shared mutable state. This can be avoided by simply giving the new independent clone an unique owned copy of the data, as should likely be done anyway.

Required Methods§

Source

fn independent_clone(&self) -> Self

Get a deep clone of a value, which does not share any semantically-important mutable state.

The goal is that the independent clone and its source appear to act completely independently, at least from their public interfaces; mutating or dropping one clone (among possible actions) should have no potentially-observable effect on any other independent clone.

Read IndependentClone for more.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Trait IndependentCloneCopy item path

§Exceptions

§Other edge cases

Required Methods§

fn independent_clone(&self) -> Self

Dyn Compatibility§

Implementations on Foreign Types§

impl IndependentClone<AnySpeed> for Box<str>

fn independent_clone(&self) -> Self

impl IndependentClone<AnySpeed> for Pin<Box<str>>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for Ordering

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for Infallible

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for Ordering

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for bool

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for char

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for f32

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for f64

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for i8

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for i16

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for i32

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for i64

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for i128

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for isize

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for u8

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for u16

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for u32

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for u64

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for u128

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for ()

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for usize

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for Layout

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for TypeId

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for PhantomPinned

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<i8>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<i16>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<i32>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<i64>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<i128>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<isize>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<u8>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<u16>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<u32>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<u64>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<u128>

fn independent_clone(&self) -> Self

impl IndependentClone<NearInstant> for NonZero<usize>

Trait IndependentClone

impl<K, V> IndependentClone<AnySpeed> for BTreeMap<K, V>
where K: IndependentClone<AnySpeed> + Ord, V: IndependentClone<AnySpeed>,

impl<K, V, S> IndependentClone<AnySpeed> for HashMap<K, V, S>
where K: IndependentClone<AnySpeed> + Eq + Hash, V: IndependentClone<AnySpeed>, S: BuildHasher + Default,