Struct tokio::sync::OwnedRwLockReadGuard
source · [−]Expand description
Owned RAII structure used to release the shared read access of a lock when dropped.
This structure is created by the read_owned
method on
RwLock
.
Implementations
sourceimpl<T: ?Sized, U: ?Sized> OwnedRwLockReadGuard<T, U>
impl<T: ?Sized, U: ?Sized> OwnedRwLockReadGuard<T, U>
sourcepub fn map<F, V: ?Sized>(this: Self, f: F) -> OwnedRwLockReadGuard<T, V> where
F: FnOnce(&U) -> &V,
pub fn map<F, V: ?Sized>(this: Self, f: F) -> OwnedRwLockReadGuard<T, V> where
F: FnOnce(&U) -> &V,
Makes a new OwnedRwLockReadGuard
for a component of the locked data.
This operation cannot fail as the OwnedRwLockReadGuard
passed in
already locked the data.
This is an associated function that needs to be
used as OwnedRwLockReadGuard::map(...)
. A method would interfere with
methods of the same name on the contents of the locked data.
Examples
use std::sync::Arc;
use tokio::sync::{RwLock, OwnedRwLockReadGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let lock = Arc::new(RwLock::new(Foo(1)));
let guard = lock.read_owned().await;
let guard = OwnedRwLockReadGuard::map(guard, |f| &f.0);
assert_eq!(1, *guard);
sourcepub fn try_map<F, V: ?Sized>(
this: Self,
f: F
) -> Result<OwnedRwLockReadGuard<T, V>, Self> where
F: FnOnce(&U) -> Option<&V>,
pub fn try_map<F, V: ?Sized>(
this: Self,
f: F
) -> Result<OwnedRwLockReadGuard<T, V>, Self> where
F: FnOnce(&U) -> Option<&V>,
Attempts to make a new OwnedRwLockReadGuard
for a component of the
locked data. The original guard is returned if the closure returns
None
.
This operation cannot fail as the OwnedRwLockReadGuard
passed in
already locked the data.
This is an associated function that needs to be used as
OwnedRwLockReadGuard::try_map(..)
. A method would interfere with
methods of the same name on the contents of the locked data.
Examples
use std::sync::Arc;
use tokio::sync::{RwLock, OwnedRwLockReadGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let lock = Arc::new(RwLock::new(Foo(1)));
let guard = lock.read_owned().await;
let guard = OwnedRwLockReadGuard::try_map(guard, |f| Some(&f.0)).expect("should not fail");
assert_eq!(1, *guard);
Trait Implementations
sourceimpl<T: ?Sized, U: ?Sized> Deref for OwnedRwLockReadGuard<T, U>
impl<T: ?Sized, U: ?Sized> Deref for OwnedRwLockReadGuard<T, U>
sourceimpl<T: ?Sized, U: ?Sized> Drop for OwnedRwLockReadGuard<T, U>
impl<T: ?Sized, U: ?Sized> Drop for OwnedRwLockReadGuard<T, U>
impl<T, U> Send for OwnedRwLockReadGuard<T, U> where
T: ?Sized + Send + Sync,
U: ?Sized + Sync,
impl<T, U> Sync for OwnedRwLockReadGuard<T, U> where
T: ?Sized + Send + Sync,
U: ?Sized + Send + Sync,
Auto Trait Implementations
impl<T, U = T> !RefUnwindSafe for OwnedRwLockReadGuard<T, U>
impl<T: ?Sized, U: ?Sized> Unpin for OwnedRwLockReadGuard<T, U> where
T: Unpin,
impl<T, U = T> !UnwindSafe for OwnedRwLockReadGuard<T, U>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
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