Struct holochain::prelude::kitsune_p2p::dependencies::kitsune_p2p_types::dependencies::lair_keystore_api::dependencies::tokio::sync::RwLockWriteGuard
source · pub struct RwLockWriteGuard<'a, T>where
T: ?Sized,{ /* private fields */ }
Expand description
Implementations
sourceimpl<'a, T> RwLockWriteGuard<'a, T>where
T: ?Sized,
impl<'a, T> RwLockWriteGuard<'a, T>where
T: ?Sized,
sourcepub fn map<F, U>(
this: RwLockWriteGuard<'a, T>,
f: F
) -> RwLockMappedWriteGuard<'a, U>where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
pub fn map<F, U>(
this: RwLockWriteGuard<'a, T>,
f: F
) -> RwLockMappedWriteGuard<'a, U>where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
Makes a new RwLockMappedWriteGuard
for a component of the locked data.
This operation cannot fail as the RwLockWriteGuard
passed in already
locked the data.
This is an associated function that needs to be used as
RwLockWriteGuard::map(..)
. A method would interfere with methods of
the same name on the contents of the locked data.
This is an asynchronous version of RwLockWriteGuard::map
from the
parking_lot
crate.
Examples
use tokio::sync::{RwLock, RwLockWriteGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let lock = RwLock::new(Foo(1));
{
let mut mapped = RwLockWriteGuard::map(lock.write().await, |f| &mut f.0);
*mapped = 2;
}
assert_eq!(Foo(2), *lock.read().await);
sourcepub fn try_map<F, U>(
this: RwLockWriteGuard<'a, T>,
f: F
) -> Result<RwLockMappedWriteGuard<'a, U>, RwLockWriteGuard<'a, T>>where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
pub fn try_map<F, U>(
this: RwLockWriteGuard<'a, T>,
f: F
) -> Result<RwLockMappedWriteGuard<'a, U>, RwLockWriteGuard<'a, T>>where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
Attempts to make a new RwLockMappedWriteGuard
for a component of
the locked data. The original guard is returned if the closure returns
None
.
This operation cannot fail as the RwLockWriteGuard
passed in already
locked the data.
This is an associated function that needs to be
used as RwLockWriteGuard::try_map(...)
. A method would interfere with
methods of the same name on the contents of the locked data.
This is an asynchronous version of RwLockWriteGuard::try_map
from
the parking_lot
crate.
Examples
use tokio::sync::{RwLock, RwLockWriteGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let lock = RwLock::new(Foo(1));
{
let guard = lock.write().await;
let mut guard = RwLockWriteGuard::try_map(guard, |f| Some(&mut f.0)).expect("should not fail");
*guard = 2;
}
assert_eq!(Foo(2), *lock.read().await);
sourcepub fn into_mapped(
this: RwLockWriteGuard<'a, T>
) -> RwLockMappedWriteGuard<'a, T>
pub fn into_mapped(
this: RwLockWriteGuard<'a, T>
) -> RwLockMappedWriteGuard<'a, T>
Converts this RwLockWriteGuard
into an RwLockMappedWriteGuard
. This
method can be used to store a non-mapped guard in a struct field that
expects a mapped guard.
This is equivalent to calling RwLockWriteGuard::map(guard, |me| me)
.
sourcepub fn downgrade(self) -> RwLockReadGuard<'a, T>
pub fn downgrade(self) -> RwLockReadGuard<'a, T>
Atomically downgrades a write lock into a read lock without allowing any writers to take exclusive access of the lock in the meantime.
Note: This won’t necessarily allow any additional readers to acquire
locks, since RwLock
is fair and it is possible that a writer is next
in line.
Returns an RAII guard which will drop this read access of the RwLock
when dropped.
Examples
let lock = Arc::new(RwLock::new(1));
let n = lock.write().await;
let cloned_lock = lock.clone();
let handle = tokio::spawn(async move {
*cloned_lock.write().await = 2;
});
let n = n.downgrade();
assert_eq!(*n, 1, "downgrade is atomic");
drop(n);
handle.await.unwrap();
assert_eq!(*lock.read().await, 2, "second writer obtained write lock");
Trait Implementations
sourceimpl<'a, T> Debug for RwLockWriteGuard<'a, T>where
T: Debug + ?Sized,
impl<'a, T> Debug for RwLockWriteGuard<'a, T>where
T: Debug + ?Sized,
sourceimpl<T> Deref for RwLockWriteGuard<'_, T>where
T: ?Sized,
impl<T> Deref for RwLockWriteGuard<'_, T>where
T: ?Sized,
sourceimpl<T> DerefMut for RwLockWriteGuard<'_, T>where
T: ?Sized,
impl<T> DerefMut for RwLockWriteGuard<'_, T>where
T: ?Sized,
sourceimpl<'a, T> Display for RwLockWriteGuard<'a, T>where
T: Display + ?Sized,
impl<'a, T> Display for RwLockWriteGuard<'a, T>where
T: Display + ?Sized,
sourceimpl<'a, T> Drop for RwLockWriteGuard<'a, T>where
T: ?Sized,
impl<'a, T> Drop for RwLockWriteGuard<'a, T>where
T: ?Sized,
impl<T> Send for RwLockWriteGuard<'_, T>where
T: Send + Sync + ?Sized,
impl<T> Sync for RwLockWriteGuard<'_, T>where
T: Send + Sync + ?Sized,
Auto Trait Implementations
impl<'a, T> !RefUnwindSafe for RwLockWriteGuard<'a, T>
impl<'a, T: ?Sized> Unpin for RwLockWriteGuard<'a, T>
impl<'a, T> !UnwindSafe for RwLockWriteGuard<'a, 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
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
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
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>
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>
self
from the equivalent element of its
superset. Read morefn 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.