Struct holochain::prelude::dependencies::kitsune_p2p_types::dependencies::lair_keystore_api::dependencies::tokio::task::LocalKey
source · pub struct LocalKey<T>where
T: 'static,{ /* private fields */ }
Expand description
A key for task-local data.
This type is generated by the task_local!
macro.
Unlike std::thread::LocalKey
, tokio::task::LocalKey
will
not lazily initialize the value on first access. Instead, the
value is first initialized when the future containing
the task-local is first polled by a futures executor, like Tokio.
Examples
tokio::task_local! {
static NUMBER: u32;
}
NUMBER.scope(1, async move {
assert_eq!(NUMBER.get(), 1);
}).await;
NUMBER.scope(2, async move {
assert_eq!(NUMBER.get(), 2);
NUMBER.scope(3, async move {
assert_eq!(NUMBER.get(), 3);
}).await;
}).await;
Implementations
sourceimpl<T> LocalKey<T>where
T: 'static,
impl<T> LocalKey<T>where
T: 'static,
sourcepub fn scope<F>(&'static self, value: T, f: F) -> TaskLocalFuture<T, F> ⓘwhere
F: Future,
pub fn scope<F>(&'static self, value: T, f: F) -> TaskLocalFuture<T, F> ⓘwhere
F: Future,
Sets a value T
as the task-local value for the future F
.
On completion of scope
, the task-local will be dropped.
Panics
If you poll the returned future inside a call to with
or
try_with
on the same LocalKey
, then the call to poll
will panic.
Examples
tokio::task_local! {
static NUMBER: u32;
}
NUMBER.scope(1, async move {
println!("task local value: {}", NUMBER.get());
}).await;
sourcepub fn sync_scope<F, R>(&'static self, value: T, f: F) -> Rwhere
F: FnOnce() -> R,
pub fn sync_scope<F, R>(&'static self, value: T, f: F) -> Rwhere
F: FnOnce() -> R,
Sets a value T
as the task-local value for the closure F
.
On completion of scope
, the task-local will be dropped.
Panics
This method panics if called inside a call to with
or try_with
on the same LocalKey
.
Examples
tokio::task_local! {
static NUMBER: u32;
}
NUMBER.sync_scope(1, || {
println!("task local value: {}", NUMBER.get());
});
Trait Implementations
Auto Trait Implementations
impl<T> RefUnwindSafe for LocalKey<T>
impl<T> Send for LocalKey<T>
impl<T> Sync for LocalKey<T>
impl<T> Unpin for LocalKey<T>
impl<T> UnwindSafe for LocalKey<T>
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
TODO: once 1.33.0 is the minimum supported compiler version, remove
Any::type_id_compat and use StdAny::type_id instead.
https://github.com/rust-lang/rust/issues/27745 Read more
impl<T> ArchivePointee for T
impl<T> ArchivePointee for T
type ArchivedMetadata = ()
type ArchivedMetadata = ()
The archived version of the pointer metadata for this type.
fn pointer_metadata(
_: &<T as ArchivePointee>::ArchivedMetadata
) -> <T as Pointee>::Metadata
fn pointer_metadata(
_: &<T as ArchivePointee>::ArchivedMetadata
) -> <T as Pointee>::Metadata
Converts some archived metadata to the pointer metadata for itself.
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
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>
Deserializes using the given deserializer
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> ⓘ
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
sourcefn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
sourcefn 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>
The inverse inclusion map: attempts to construct
self
from the equivalent element of its
superset. Read morefn is_in_subset(&self) -> bool
fn is_in_subset(&self) -> bool
Checks if
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
Use with care! Same as
self.to_subset
but without any property checks. Always succeeds.fn from_subset(element: &SS) -> SP
fn from_subset(element: &SS) -> SP
The inclusion map: converts
self
to the equivalent element of its superset.impl<T> Upcastable for Twhere
T: 'static + Any + Send + Sync,
impl<T> Upcastable for Twhere
T: 'static + Any + Send + Sync,
fn upcast_any_ref(&self) -> &(dyn Any + 'static)
fn upcast_any_ref(&self) -> &(dyn Any + 'static)
upcast ref
fn upcast_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn upcast_any_mut(&mut self) -> &mut (dyn Any + 'static)
upcast mut ref