Struct holochain::prelude::dependencies::kitsune_p2p_types::dependencies::lair_keystore_api::dependencies::tokio::sync::MutexGuard
source · pub struct MutexGuard<'a, T>where
T: ?Sized,{ /* private fields */ }
Expand description
A handle to a held Mutex
. The guard can be held across any .await
point
as it is Send
.
As long as you have this guard, you have exclusive access to the underlying
T
. The guard internally borrows the Mutex
, so the mutex will not be
dropped while a guard exists.
The lock is automatically released whenever the guard is dropped, at which
point lock
will succeed yet again.
Implementations§
source§impl<'a, T> MutexGuard<'a, T>where
T: ?Sized,
impl<'a, T> MutexGuard<'a, T>where
T: ?Sized,
sourcepub fn map<U, F>(this: MutexGuard<'a, T>, f: F) -> MappedMutexGuard<'a, U>where
F: FnOnce(&mut T) -> &mut U,
pub fn map<U, F>(this: MutexGuard<'a, T>, f: F) -> MappedMutexGuard<'a, U>where
F: FnOnce(&mut T) -> &mut U,
Makes a new MappedMutexGuard
for a component of the locked data.
This operation cannot fail as the MutexGuard
passed in already locked the mutex.
This is an associated function that needs to be used as MutexGuard::map(...)
. A method
would interfere with methods of the same name on the contents of the locked data.
Examples
use tokio::sync::{Mutex, MutexGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let foo = Mutex::new(Foo(1));
{
let mut mapped = MutexGuard::map(foo.lock().await, |f| &mut f.0);
*mapped = 2;
}
assert_eq!(Foo(2), *foo.lock().await);
sourcepub fn try_map<U, F>(
this: MutexGuard<'a, T>,
f: F
) -> Result<MappedMutexGuard<'a, U>, MutexGuard<'a, T>>where
F: FnOnce(&mut T) -> Option<&mut U>,
pub fn try_map<U, F>(
this: MutexGuard<'a, T>,
f: F
) -> Result<MappedMutexGuard<'a, U>, MutexGuard<'a, T>>where
F: FnOnce(&mut T) -> Option<&mut U>,
Attempts to make a new MappedMutexGuard
for a component of the locked data. The
original guard is returned if the closure returns None
.
This operation cannot fail as the MutexGuard
passed in already locked the mutex.
This is an associated function that needs to be used as MutexGuard::try_map(...)
. A
method would interfere with methods of the same name on the contents of the locked data.
Examples
use tokio::sync::{Mutex, MutexGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let foo = Mutex::new(Foo(1));
{
let mut mapped = MutexGuard::try_map(foo.lock().await, |f| Some(&mut f.0))
.expect("should not fail");
*mapped = 2;
}
assert_eq!(Foo(2), *foo.lock().await);
sourcepub fn mutex(this: &MutexGuard<'a, T>) -> &'a Mutex<T>
pub fn mutex(this: &MutexGuard<'a, T>) -> &'a Mutex<T>
Returns a reference to the original Mutex
.
use tokio::sync::{Mutex, MutexGuard};
async fn unlock_and_relock<'l>(guard: MutexGuard<'l, u32>) -> MutexGuard<'l, u32> {
println!("1. contains: {:?}", *guard);
let mutex = MutexGuard::mutex(&guard);
drop(guard);
let guard = mutex.lock().await;
println!("2. contains: {:?}", *guard);
guard
}
Trait Implementations§
source§impl<T> Deref for MutexGuard<'_, T>where
T: ?Sized,
impl<T> Deref for MutexGuard<'_, T>where
T: ?Sized,
source§impl<T> DerefMut for MutexGuard<'_, T>where
T: ?Sized,
impl<T> DerefMut for MutexGuard<'_, T>where
T: ?Sized,
source§impl<T> Drop for MutexGuard<'_, T>where
T: ?Sized,
impl<T> Drop for MutexGuard<'_, T>where
T: ?Sized,
impl<T> Sync for MutexGuard<'_, T>where
T: Send + Sync + ?Sized,
Auto Trait Implementations§
impl<'a, T> !RefUnwindSafe for MutexGuard<'a, T>
impl<'a, T: ?Sized> Send for MutexGuard<'a, T>where
T: Send,
impl<'a, T: ?Sized> Unpin for MutexGuard<'a, T>
impl<'a, T> !UnwindSafe for MutexGuard<'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
§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> ⓘ
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.