Struct tokio::sync::RwLockMappedWriteGuard [−][src]
pub struct RwLockMappedWriteGuard<'a, T: ?Sized> { /* fields omitted */ }
sync
only.Expand description
RAII structure used to release the exclusive write access of a lock when dropped.
This structure is created by mapping an RwLockWriteGuard
. It is a
separate type from RwLockWriteGuard
to disallow downgrading a mapped
guard, since doing so can cause undefined behavior.
Implementations
Make a new RwLockMappedWriteGuard
for a component of the locked data.
This operation cannot fail as the RwLockMappedWriteGuard
passed in already
locked the data.
This is an associated function that needs to be used as
RwLockMappedWriteGuard::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);
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 RwLockMappedWriteGuard
passed in already
locked the data.
This is an associated function that needs to be
used as RwLockMappedWriteGuard::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);
Trait Implementations
Auto Trait Implementations
impl<'a, T> !RefUnwindSafe for RwLockMappedWriteGuard<'a, T>
impl<'a, T: ?Sized> Unpin for RwLockMappedWriteGuard<'a, T>
impl<'a, T> !UnwindSafe for RwLockMappedWriteGuard<'a, T>