Struct MutexGuard
pub struct MutexGuard<'a, T: ?Sized> { /* private fields */ }sync only.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
impl<'a, T: ?Sized> MutexGuard<'a, T>
pub fn map<U, F>(this: Self, f: F) -> MappedMutexGuard<'a, 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);pub fn try_map<U, F>(this: Self, f: F) -> Result<MappedMutexGuard<'a, U>, Self>
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);pub fn mutex(this: &Self) -> &'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
impl<T: ?Sized + Debug> Debug for MutexGuard<'_, T>
impl<T: ?Sized> Deref for MutexGuard<'_, T>
impl<T: ?Sized> DerefMut for MutexGuard<'_, T>
impl<T: ?Sized + Display> Display for MutexGuard<'_, T>
impl<T: ?Sized> Drop for MutexGuard<'_, T>
impl<T> Sync for MutexGuard<'_, T>
Auto Trait Implementations
impl<'a, T> !RefUnwindSafe for MutexGuard<'a, T>
impl<'a, T> !UnwindSafe for MutexGuard<'a, T>
impl<'a, T> Freeze for MutexGuard<'a, T>where T: ?Sized,
impl<'a, T> Send for MutexGuard<'a, T>
impl<'a, T> Unpin for MutexGuard<'a, T>where T: ?Sized,
impl<'a, T> UnsafeUnpin for MutexGuard<'a, T>where T: ?Sized,
Blanket Implementations
impl<T> BorrowMut<T> for Twhere T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
impl<T> Instrument for T
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
impl<P, T> Receiver for P
type Target = T
arbitrary_self_types)
impl<T> ToString for T
impl<T> WithSubscriber for T
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> ⓘ
fn with_current_subscriber(self) -> WithDispatch<Self> ⓘ
MIT License
Copyright © Tokio Contributors
https://docs.rs/tokio/1.53.1/tokio/sync/struct.MutexGuard.html
