Struct SemiSticky 

pub struct SemiSticky<T: 'static> { /* private fields */ }

A SemiSticky<T> keeps a value T stored in a thread if it has a drop.

This is a combined version of Fragile and Sticky. If the type does not have a drop it will effectively be a Fragile, otherwise it will be internally behave like a Sticky.

This type requires T: 'static for the same reasons as Sticky and exposes the value only through scoped callbacks. Like Sticky, it is Unpin only if T is Unpin.

Implementations

impl<T> SemiSticky<T>

pub fn new(value: T) -> Self

Creates a new SemiSticky wrapping a value.

The value that is moved into the SemiSticky can be non Send and will be anchored to the thread that created the object. If the sticky wrapper type ends up being send from thread to thread only the original thread can interact with the value. In case the value does not have Drop it will be stored in the Fragile instead.

pub fn is_valid(&self) -> bool

Returns true if the access is valid.

This will be false if the value was sent to another thread. For values stored in Sticky, it is also false once their registry starts being destroyed. Values without drop glue do not depend on the registry.

pub fn into_inner(self) -> T

Consumes the SemiSticky, returning the wrapped value.

Panics

Panics if called from a different thread than the one where the original value was created.

pub fn try_into_inner(self) -> Result<T, Self>

Consumes the SemiSticky, returning the wrapped value if successful.

The wrapped value is returned if this is called from the same thread as the one where the original value was created, otherwise the SemiSticky is returned as Err(self).

pub fn with<R, F>(&self, f: F) -> R

where F: for<'a> FnOnce(&'a T) -> R,

Invokes a callback with a shared reference to the wrapped value.

The callback may return owned data, but it cannot return a reference derived from the wrapped value.

use fragile::SemiSticky;

let value = SemiSticky::new(String::from("hello"));
let length = value.with(String::len);
assert_eq!(length, 5);

Panics

Panics if the calling thread is not the one that wrapped the value, or if its thread-local registry has been destroyed. For a non-panicking variant, use try_with.

pub fn with_mut<R, F>(&mut self, f: F) -> R

where F: for<'a> FnOnce(&'a mut T) -> R,

Invokes a callback with an exclusive reference to the wrapped value.

The callback may return owned data, but it cannot return a reference derived from the wrapped value.

Panics

Panics if the calling thread is not the one that wrapped the value, or if its thread-local registry has been destroyed. For a non-panicking variant, use try_with_mut.

pub fn try_with<R, F>(&self, f: F) -> Result<R, InvalidThreadAccess>

where F: for<'a> FnOnce(&'a T) -> R,

Invokes a callback with a shared reference to the wrapped value.

As with with, the callback cannot return a reference derived from the wrapped value.

Returns InvalidThreadAccess without invoking the callback if is_valid is false.

pub fn try_with_mut<R, F>(&mut self, f: F) -> Result<R, InvalidThreadAccess>

where F: for<'a> FnOnce(&'a mut T) -> R,

Invokes a callback with an exclusive reference to the wrapped value.

As with with_mut, the callback cannot return a reference derived from the wrapped value.

Returns InvalidThreadAccess without invoking the callback if is_valid is false.

Trait Implementations

impl<T: Clone> Clone for SemiSticky<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for SemiSticky<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for SemiSticky<T>

fn default() -> SemiSticky<T>

Returns the “default value” for a type.

impl<T: Display> Display for SemiSticky<T>

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

Formats the value using the given formatter.

impl<T: Eq> Eq for SemiSticky<T>

impl<T> From<T> for SemiSticky<T>

fn from(t: T) -> SemiSticky<T>

Converts to this type from the input type.

impl<F: Future> Future for SemiSticky<F>

type Output = <F as Future>::Output

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

impl<T: Ord> Ord for SemiSticky<T>

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

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

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

Restrict a value to a certain range.

impl<T: PartialEq> PartialEq for SemiSticky<T>

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

Equality operator ==.

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

Inequality operator !=.

impl<T: PartialOrd> PartialOrd for SemiSticky<T>

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

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

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

Tests less than (for self and other) and is used by the < operator.

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

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

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

Tests greater than (for self and other) and is used by the > operator.

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

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

impl<S: Stream> Stream for SemiSticky<S>

type Item = <S as Stream>::Item

Values yielded by the stream.

fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.