Trait evmap::shallow_copy::ShallowCopy

pub trait ShallowCopy {
    pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>;
}

Types that implement this trait can be cheaply copied by (potentially) aliasing the data they contain. Only the last shallow copy will be dropped -- all others will be silently leaked (with mem::forget).

To implement this trait for your own Copy type, write:

use std::mem::ManuallyDrop;

#[derive(Copy, Clone)]
struct T;

impl ShallowCopy for T {
    unsafe fn shallow_copy(&self) -> ManuallyDrop<Self> {
        ManuallyDrop::new(*self)
    }
}

If you have a non-Copy type, the value returned by shallow_copy should point to the same data as the &mut self, and it should be safe to mem::forget either of the copies as long as the other is dropped normally afterwards.

For complex, non-Copy types, you can place the type behind a wrapper that implements ShallowCopy such as Box or Arc. Alternatively, if your type is made up of types that all implement ShallowCopy, consider using the evmap-derive crate, which contains a derive macro for ShallowCopy. See that crate's documentation for details.

Required methods

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

Perform an aliasing copy of this value.

Safety

The use of this method is only safe if the values involved are never mutated, and only one of the copies is dropped; the remaining copies must be forgotten with mem::forget.

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Implementations on Foreign Types

impl<T> ShallowCopy for Arc<T> where
    T: ?Sized, 

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<T> ShallowCopy for Rc<T> where
    T: ?Sized, 

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<T> ShallowCopy for Box<T> where
    T: ?Sized, 

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<T> ShallowCopy for Option<T> where
    T: ShallowCopy, 

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for String

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<T> ShallowCopy for Vec<T>

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<'a, T> ShallowCopy for &'a T where
    T: ?Sized, 

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for ()

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for bool

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for char

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for usize

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for u8

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for u16

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for u32

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for u64

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for u128

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for isize

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for i8

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for i16

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for i32

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for i64

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for i128

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for f32

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl ShallowCopy for f64

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy> ShallowCopy for (A,)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy> ShallowCopy for (A, B)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy> ShallowCopy for (A, B, C)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy> ShallowCopy for (A, B, C, D)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy> ShallowCopy for (A, B, C, D, E)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy> ShallowCopy for (A, B, C, D, E, F)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy, G: ShallowCopy> ShallowCopy for (A, B, C, D, E, F, G)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy, G: ShallowCopy, H: ShallowCopy> ShallowCopy for (A, B, C, D, E, F, G, H)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy, G: ShallowCopy, H: ShallowCopy, I: ShallowCopy> ShallowCopy for (A, B, C, D, E, F, G, H, I)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy, G: ShallowCopy, H: ShallowCopy, I: ShallowCopy, J: ShallowCopy> ShallowCopy for (A, B, C, D, E, F, G, H, I, J)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy, G: ShallowCopy, H: ShallowCopy, I: ShallowCopy, J: ShallowCopy, K: ShallowCopy> ShallowCopy for (A, B, C, D, E, F, G, H, I, J, K)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

impl<A: ShallowCopy, B: ShallowCopy, C: ShallowCopy, D: ShallowCopy, E: ShallowCopy, F: ShallowCopy, G: ShallowCopy, H: ShallowCopy, I: ShallowCopy, J: ShallowCopy, K: ShallowCopy, L: ShallowCopy> ShallowCopy for (A, B, C, D, E, F, G, H, I, J, K, L)

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

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Implementors

impl<T> ShallowCopy for CopyValue<T> where
    T: Copy, 

pub unsafe fn shallow_copy(&self) -> ManuallyDrop<Self>

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