Enum holochain::prelude::dependencies::kitsune_p2p_types::dependencies::futures::task::Poll
1.36.0 · source · pub enum Poll<T> {
Ready(T),
Pending,
}
Expand description
Indicates whether a value is available or if the current task has been scheduled to receive a wakeup instead.
Variants§
Ready(T)
Represents that a value is immediately ready.
Pending
Represents that a value is not ready yet.
When a function returns Pending
, the function must also
ensure that the current task is scheduled to be awoken when
progress can be made.
Implementations§
source§impl<T> Poll<T>
impl<T> Poll<T>
sourcepub fn map<U, F>(self, f: F) -> Poll<U>where
F: FnOnce(T) -> U,
pub fn map<U, F>(self, f: F) -> Poll<U>where
F: FnOnce(T) -> U,
Maps a Poll<T>
to Poll<U>
by applying a function to a contained value.
Examples
Converts a Poll<String>
into a Poll<usize>
, consuming
the original:
let poll_some_string = Poll::Ready(String::from("Hello, World!"));
// `Poll::map` takes self *by value*, consuming `poll_some_string`
let poll_some_len = poll_some_string.map(|s| s.len());
assert_eq!(poll_some_len, Poll::Ready(13));
const: 1.49.0 · sourcepub const fn is_ready(&self) -> bool
pub const fn is_ready(&self) -> bool
Returns true
if the poll is a Poll::Ready
value.
Examples
let x: Poll<u32> = Poll::Ready(2);
assert_eq!(x.is_ready(), true);
let x: Poll<u32> = Poll::Pending;
assert_eq!(x.is_ready(), false);
const: 1.49.0 · sourcepub const fn is_pending(&self) -> bool
pub const fn is_pending(&self) -> bool
sourcepub fn ready(self) -> Ready<T>
🔬This is a nightly-only experimental API. (poll_ready
)
pub fn ready(self) -> Ready<T>
poll_ready
)Extracts the successful type of a Poll<T>
.
When combined with the ?
operator, this function will
propagate any Poll::Pending
values to the caller, and
extract the T
from Poll::Ready
.
Examples
#![feature(poll_ready)]
use std::task::{Context, Poll};
use std::future::{self, Future};
use std::pin::Pin;
pub fn do_poll(cx: &mut Context<'_>) -> Poll<()> {
let mut fut = future::ready(42);
let fut = Pin::new(&mut fut);
let num = fut.poll(cx).ready()?;
// ... use num
Poll::Ready(())
}
source§impl<T, E> Poll<Result<T, E>>
impl<T, E> Poll<Result<T, E>>
sourcepub fn map_ok<U, F>(self, f: F) -> Poll<Result<U, E>>where
F: FnOnce(T) -> U,
pub fn map_ok<U, F>(self, f: F) -> Poll<Result<U, E>>where
F: FnOnce(T) -> U,
Maps a Poll<Result<T, E>>
to Poll<Result<U, E>>
by applying a
function to a contained Poll::Ready(Ok)
value, leaving all other
variants untouched.
This function can be used to compose the results of two functions.
Examples
let res: Poll<Result<u8, _>> = Poll::Ready("12".parse());
let squared = res.map_ok(|n| n * n);
assert_eq!(squared, Poll::Ready(Ok(144)));
sourcepub fn map_err<U, F>(self, f: F) -> Poll<Result<T, U>>where
F: FnOnce(E) -> U,
pub fn map_err<U, F>(self, f: F) -> Poll<Result<T, U>>where
F: FnOnce(E) -> U,
Maps a Poll::Ready<Result<T, E>>
to Poll::Ready<Result<T, F>>
by
applying a function to a contained Poll::Ready(Err)
value, leaving all other
variants untouched.
This function can be used to pass through a successful result while handling an error.
Examples
let res: Poll<Result<u8, _>> = Poll::Ready("oops".parse());
let res = res.map_err(|_| 0_u8);
assert_eq!(res, Poll::Ready(Err(0)));
source§impl<T, E> Poll<Option<Result<T, E>>>
impl<T, E> Poll<Option<Result<T, E>>>
1.51.0 · sourcepub fn map_ok<U, F>(self, f: F) -> Poll<Option<Result<U, E>>>where
F: FnOnce(T) -> U,
pub fn map_ok<U, F>(self, f: F) -> Poll<Option<Result<U, E>>>where
F: FnOnce(T) -> U,
Maps a Poll<Option<Result<T, E>>>
to Poll<Option<Result<U, E>>>
by
applying a function to a contained Poll::Ready(Some(Ok))
value,
leaving all other variants untouched.
This function can be used to compose the results of two functions.
Examples
let res: Poll<Option<Result<u8, _>>> = Poll::Ready(Some("12".parse()));
let squared = res.map_ok(|n| n * n);
assert_eq!(squared, Poll::Ready(Some(Ok(144))));
1.51.0 · sourcepub fn map_err<U, F>(self, f: F) -> Poll<Option<Result<T, U>>>where
F: FnOnce(E) -> U,
pub fn map_err<U, F>(self, f: F) -> Poll<Option<Result<T, U>>>where
F: FnOnce(E) -> U,
Maps a Poll::Ready<Option<Result<T, E>>>
to
Poll::Ready<Option<Result<T, F>>>
by applying a function to a
contained Poll::Ready(Some(Err))
value, leaving all other variants
untouched.
This function can be used to pass through a successful result while handling an error.
Examples
let res: Poll<Option<Result<u8, _>>> = Poll::Ready(Some("oops".parse()));
let res = res.map_err(|_| 0_u8);
assert_eq!(res, Poll::Ready(Some(Err(0))));
Trait Implementations§
source§impl<T> FromResidual<Ready<Infallible>> for Poll<T>
impl<T> FromResidual<Ready<Infallible>> for Poll<T>
source§fn from_residual(residual: Ready<Infallible>) -> Poll<T>
fn from_residual(residual: Ready<Infallible>) -> Poll<T>
try_trait_v2
)Residual
type. Read moresource§impl<T, E, F> FromResidual<Result<Infallible, E>> for Poll<Option<Result<T, F>>>where
F: From<E>,
impl<T, E, F> FromResidual<Result<Infallible, E>> for Poll<Option<Result<T, F>>>where
F: From<E>,
source§fn from_residual(x: Result<Infallible, E>) -> Poll<Option<Result<T, F>>>
fn from_residual(x: Result<Infallible, E>) -> Poll<Option<Result<T, F>>>
try_trait_v2
)Residual
type. Read moresource§impl<T, E, F> FromResidual<Result<Infallible, E>> for Poll<Result<T, F>>where
F: From<E>,
impl<T, E, F> FromResidual<Result<Infallible, E>> for Poll<Result<T, F>>where
F: From<E>,
source§fn from_residual(x: Result<Infallible, E>) -> Poll<Result<T, F>>
fn from_residual(x: Result<Infallible, E>) -> Poll<Result<T, F>>
try_trait_v2
)Residual
type. Read moresource§impl<T> Ord for Poll<T>where
T: Ord,
impl<T> Ord for Poll<T>where
T: Ord,
source§impl<T> PartialEq<Poll<T>> for Poll<T>where
T: PartialEq<T>,
impl<T> PartialEq<Poll<T>> for Poll<T>where
T: PartialEq<T>,
source§impl<T> PartialOrd<Poll<T>> for Poll<T>where
T: PartialOrd<T>,
impl<T> PartialOrd<Poll<T>> for Poll<T>where
T: PartialOrd<T>,
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresource§impl<T, E> Try for Poll<Option<Result<T, E>>>
impl<T, E> Try for Poll<Option<Result<T, E>>>
§type Output = Poll<Option<T>>
type Output = Poll<Option<T>>
try_trait_v2
)?
when not short-circuiting.§type Residual = Result<Infallible, E>
type Residual = Result<Infallible, E>
try_trait_v2
)FromResidual::from_residual
as part of ?
when short-circuiting. Read moresource§fn from_output(
c: <Poll<Option<Result<T, E>>> as Try>::Output
) -> Poll<Option<Result<T, E>>>
fn from_output(
c: <Poll<Option<Result<T, E>>> as Try>::Output
) -> Poll<Option<Result<T, E>>>
try_trait_v2
)Output
type. Read moresource§fn branch(
self
) -> ControlFlow<<Poll<Option<Result<T, E>>> as Try>::Residual, <Poll<Option<Result<T, E>>> as Try>::Output>
fn branch(
self
) -> ControlFlow<<Poll<Option<Result<T, E>>> as Try>::Residual, <Poll<Option<Result<T, E>>> as Try>::Output>
try_trait_v2
)?
to decide whether the operator should produce a value
(because this returned ControlFlow::Continue
)
or propagate a value back to the caller
(because this returned ControlFlow::Break
). Read moresource§impl<T, E> Try for Poll<Result<T, E>>
impl<T, E> Try for Poll<Result<T, E>>
§type Output = Poll<T>
type Output = Poll<T>
try_trait_v2
)?
when not short-circuiting.§type Residual = Result<Infallible, E>
type Residual = Result<Infallible, E>
try_trait_v2
)FromResidual::from_residual
as part of ?
when short-circuiting. Read moresource§fn from_output(c: <Poll<Result<T, E>> as Try>::Output) -> Poll<Result<T, E>>
fn from_output(c: <Poll<Result<T, E>> as Try>::Output) -> Poll<Result<T, E>>
try_trait_v2
)Output
type. Read moresource§fn branch(
self
) -> ControlFlow<<Poll<Result<T, E>> as Try>::Residual, <Poll<Result<T, E>> as Try>::Output>
fn branch(
self
) -> ControlFlow<<Poll<Result<T, E>> as Try>::Residual, <Poll<Result<T, E>> as Try>::Output>
try_trait_v2
)?
to decide whether the operator should produce a value
(because this returned ControlFlow::Continue
)
or propagate a value back to the caller
(because this returned ControlFlow::Break
). Read moreimpl<T> Copy for Poll<T>where
T: Copy,
impl<T> Eq for Poll<T>where
T: Eq,
impl<T> StructuralEq for Poll<T>
impl<T> StructuralPartialEq for Poll<T>
Auto Trait Implementations§
impl<T> RefUnwindSafe for Poll<T>where
T: RefUnwindSafe,
impl<T> Send for Poll<T>where
T: Send,
impl<T> Sync for Poll<T>where
T: Sync,
impl<T> Unpin for Poll<T>where
T: Unpin,
impl<T> UnwindSafe for Poll<T>where
T: UnwindSafe,
Blanket Implementations§
§impl<T> Any for Twhere
T: Any + ?Sized,
impl<T> Any for Twhere
T: Any + ?Sized,
§fn type_id_compat(&self) -> TypeId
fn type_id_compat(&self) -> TypeId
§impl<T> ArchivePointee for T
impl<T> ArchivePointee for T
§type ArchivedMetadata = ()
type ArchivedMetadata = ()
§fn pointer_metadata(
_: &<T as ArchivePointee>::ArchivedMetadata
) -> <T as Pointee>::Metadata
fn pointer_metadata(
_: &<T as ArchivePointee>::ArchivedMetadata
) -> <T as Pointee>::Metadata
§impl<F, W, T, D> Deserialize<With<T, W>, D> for Fwhere
W: DeserializeWith<F, T, D>,
D: Fallible + ?Sized,
F: ?Sized,
impl<F, W, T, D> Deserialize<With<T, W>, D> for Fwhere
W: DeserializeWith<F, T, D>,
D: Fallible + ?Sized,
F: ?Sized,
§fn deserialize(
&self,
deserializer: &mut D
) -> Result<With<T, W>, <D as Fallible>::Error>
fn deserialize(
&self,
deserializer: &mut D
) -> Result<With<T, W>, <D as Fallible>::Error>
source§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.§impl<T> FutureExt for T
impl<T> FutureExt for T
§fn with_context(self, otel_cx: Context) -> WithContext<Self> ⓘ
fn with_context(self, otel_cx: Context) -> WithContext<Self> ⓘ
§fn with_current_context(self) -> WithContext<Self> ⓘ
fn with_current_context(self) -> WithContext<Self> ⓘ
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
source§fn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
source§fn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
§impl<T> Pointable for T
impl<T> Pointable for T
§impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
§fn to_subset(&self) -> Option<SS>
fn to_subset(&self) -> Option<SS>
self
from the equivalent element of its
superset. Read more§fn is_in_subset(&self) -> bool
fn is_in_subset(&self) -> bool
self
is actually part of its subset T
(and can be converted to it).§fn to_subset_unchecked(&self) -> SS
fn to_subset_unchecked(&self) -> SS
self.to_subset
but without any property checks. Always succeeds.§fn from_subset(element: &SS) -> SP
fn from_subset(element: &SS) -> SP
self
to the equivalent element of its superset.