Struct holochain::prelude::dependencies::kitsune_p2p_types::dependencies::lair_keystore_api::dependencies::once_cell::race::OnceBox
source · pub struct OnceBox<T> { /* private fields */ }
Expand description
A thread-safe cell which can be written to only once.
Implementations
sourceimpl<T> OnceBox<T>
impl<T> OnceBox<T>
sourcepub fn set(&self, value: Box<T, Global>) -> Result<(), Box<T, Global>>
pub fn set(&self, value: Box<T, Global>) -> Result<(), Box<T, Global>>
Sets the contents of this cell to value
.
Returns Ok(())
if the cell was empty and Err(value)
if it was
full.
sourcepub fn get_or_init<F>(&self, f: F) -> &Twhere
F: FnOnce() -> Box<T, Global>,
pub fn get_or_init<F>(&self, f: F) -> &Twhere
F: FnOnce() -> Box<T, Global>,
Gets the contents of the cell, initializing it with f
if the cell was
empty.
If several threads concurrently run get_or_init
, more than one f
can
be called. However, all threads will return the same value, produced by
some f
.
sourcepub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>where
F: FnOnce() -> Result<Box<T, Global>, E>,
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E>where
F: FnOnce() -> Result<Box<T, Global>, E>,
Gets the contents of the cell, initializing it with f
if
the cell was empty. If the cell was empty and f
failed, an
error is returned.
If several threads concurrently run get_or_init
, more than one f
can
be called. However, all threads will return the same value, produced by
some f
.
Trait Implementations
impl<T> Sync for OnceBox<T>where
T: Sync + Send,
Auto Trait Implementations
impl<T> RefUnwindSafe for OnceBox<T>where
T: RefUnwindSafe,
impl<T> Send for OnceBox<T>where
T: Send,
impl<T> Unpin for OnceBox<T>
impl<T> UnwindSafe for OnceBox<T>where
T: UnwindSafe + RefUnwindSafe,
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