Struct tokio::sync::RwLockReadGuard
source · pub struct RwLockReadGuard<'a, T: ?Sized> { /* private fields */ }
Expand description
Implementations§
source§impl<'a, T: ?Sized> RwLockReadGuard<'a, T>
impl<'a, T: ?Sized> RwLockReadGuard<'a, T>
sourcepub fn map<F, U: ?Sized>(this: Self, f: F) -> RwLockReadGuard<'a, U>
pub fn map<F, U: ?Sized>(this: Self, f: F) -> RwLockReadGuard<'a, U>
Makes a new RwLockReadGuard
for a component of the locked data.
This operation cannot fail as the RwLockReadGuard
passed in already
locked the data.
This is an associated function that needs to be
used as RwLockReadGuard::map(...)
. A method would interfere with
methods of the same name on the contents of the locked data.
This is an asynchronous version of RwLockReadGuard::map
from the
parking_lot
crate.
§Examples
use tokio::sync::{RwLock, RwLockReadGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let lock = RwLock::new(Foo(1));
let guard = lock.read().await;
let guard = RwLockReadGuard::map(guard, |f| &f.0);
assert_eq!(1, *guard);
sourcepub fn try_map<F, U: ?Sized>(
this: Self,
f: F,
) -> Result<RwLockReadGuard<'a, U>, Self>
pub fn try_map<F, U: ?Sized>( this: Self, f: F, ) -> Result<RwLockReadGuard<'a, U>, Self>
Attempts to make a new RwLockReadGuard
for a component of the
locked data. The original guard is returned if the closure returns
None
.
This operation cannot fail as the RwLockReadGuard
passed in already
locked the data.
This is an associated function that needs to be used as
RwLockReadGuard::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 RwLockReadGuard::try_map
from the
parking_lot
crate.
§Examples
use tokio::sync::{RwLock, RwLockReadGuard};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);
let lock = RwLock::new(Foo(1));
let guard = lock.read().await;
let guard = RwLockReadGuard::try_map(guard, |f| Some(&f.0)).expect("should not fail");
assert_eq!(1, *guard);