Trait ontio_std::prelude::Unpin

#[lang = "unpin"]
pub auto trait Unpin { }

Types that can be safely moved after being pinned.

Since Rust itself has no notion of immovable types, and considers moves (e.g., through assignment or mem::replace) to always be safe, this trait cannot prevent types from moving by itself.

Instead it is used to prevent moves through the type system, by controlling the behavior of pointers P wrapped in the Pin<P> wrapper, which "pin" the type in place by not allowing it to be moved out of them. See the pin module documentation for more information on pinning.

Implementing this trait lifts the restrictions of pinning off a type, which then allows it to move out with functions such as mem::replace.

Unpin has no consequence at all for non-pinned data. In particular, mem::replace happily moves !Unpin data (it works for any &mut T, not just when T: Unpin). However, you cannot use mem::replace on data wrapped inside a Pin<P> because you cannot get the &mut T you need for that, and that is what makes this system work.

So this, for example, can only be done on types implementing Unpin:

use std::mem;
use std::pin::Pin;

let mut string = "this".to_string();
let mut pinned_string = Pin::new(&mut string);

// We need a mutable reference to call `mem::replace`.
// We can obtain such a reference by (implicitly) invoking `Pin::deref_mut`,
// but that is only possible because `String` implements `Unpin`.
mem::replace(&mut *pinned_string, "other".to_string());

This trait is automatically implemented for almost every type.

Implementations on Foreign Types

impl Unpin for Waker

impl !Unpin for PhantomPinned

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

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

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Implementors

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

impl<'a, T> Unpin for &'a mut T where
    T: 'a + ?Sized, 

impl<T> Unpin for *const T where
    T: ?Sized, 

impl<T> Unpin for *mut T where
    T: ?Sized, 

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

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Auto implementors

impl Unpin for Error

impl Unpin for Ordering

impl Unpin for SearchStep

impl Unpin for EventBuilder

impl Unpin for Sink

impl Unpin for TransferParam

impl Unpin for ParseBoolError

impl Unpin for Utf8Error

impl Unpin for FromUtf16Error

impl Unpin for FromUtf8Error

impl Unpin for String

impl Unpin for H160

impl Unpin for H256

impl Unpin for [u8]

impl Unpin for bool

impl Unpin for char

impl Unpin for f32

impl Unpin for f64

impl Unpin for i8

impl Unpin for i16

impl Unpin for i32

impl Unpin for i64

impl Unpin for i128

impl Unpin for isize

impl Unpin for str

impl Unpin for u8

impl Unpin for u16

impl Unpin for u32

impl Unpin for u64

impl Unpin for u128

impl Unpin for usize

impl<'a> Unpin for Source<'a>

impl<'a> Unpin for CharSearcher<'a>

impl<'a> Unpin for Bytes<'a>

impl<'a> Unpin for CharIndices<'a>

impl<'a> Unpin for Chars<'a>

impl<'a> Unpin for EncodeUtf16<'a>

impl<'a> Unpin for EscapeDebug<'a>

impl<'a> Unpin for EscapeDefault<'a>

impl<'a> Unpin for EscapeUnicode<'a>

impl<'a> Unpin for Lines<'a>

impl<'a> Unpin for LinesAny<'a>

impl<'a> Unpin for SplitAsciiWhitespace<'a>

impl<'a> Unpin for SplitWhitespace<'a>

impl<'a> Unpin for ontio_std::prelude::string::Drain<'a>

impl<'a, 'b> Unpin for CharSliceSearcher<'a, 'b>

impl<'a, 'b> Unpin for StrSearcher<'a, 'b>

impl<'a, F> Unpin for CharPredicateSearcher<'a, F> where
    F: MultiCharEq + Unpin, 

impl<'a, I> Unpin for Splice<'a, I> where
    I: Unpin, 

impl<'a, P> Unpin for MatchIndices<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for Matches<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for RMatchIndices<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for RMatches<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for RSplit<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for RSplitN<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for RSplitTerminator<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for Split<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for SplitN<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, P> Unpin for SplitTerminator<'a, P> where
    <P as Pattern<'a>>::Searcher: Unpin, 

impl<'a, T> Unpin for ontio_std::prelude::vec::Drain<'a, T>

impl<'a, T, F> Unpin for DrainFilter<'a, T, F> where
    F: Unpin, 

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

impl<T> Unpin for ListStore<T> where
    T: Unpin, 

impl<T> Unpin for Reverse<T> where
    T: Unpin, 

impl<T> Unpin for IntoIter<T> where
    T: Unpin, 

impl<T> Unpin for Vec<T> where
    T: Unpin, 

impl<T> Unpin for [T] where
    T: Unpin, 

impl<T, E> Unpin for Result<T, E> where
    E: Unpin,
    T: Unpin, 

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