pub struct OwnedRwLockMappedWriteGuard<T: ?Sized, U: ?Sized = T> { /* private fields */ }
Expand description

Owned RAII structure used to release the exclusive write access of a lock when dropped.

This structure is created by mapping an OwnedRwLockWriteGuard. It is a separate type from OwnedRwLockWriteGuard to disallow downgrading a mapped guard, since doing so can cause undefined behavior.

Implementations

Makes a new OwnedRwLockMappedWriteGuard for a component of the locked data.

This operation cannot fail as the OwnedRwLockMappedWriteGuard passed in already locked the data.

This is an associated function that needs to be used as OwnedRwLockWriteGuard::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, OwnedRwLockWriteGuard};

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);

let lock = Arc::new(RwLock::new(Foo(1)));

{
    let lock = Arc::clone(&lock);
    let mut mapped = OwnedRwLockWriteGuard::map(lock.write_owned().await, |f| &mut f.0);
    *mapped = 2;
}

assert_eq!(Foo(2), *lock.read().await);

Attempts to make a new OwnedRwLockMappedWriteGuard for a component of the locked data. The original guard is returned if the closure returns None.

This operation cannot fail as the OwnedRwLockMappedWriteGuard passed in already locked the data.

This is an associated function that needs to be used as OwnedRwLockMappedWriteGuard::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, OwnedRwLockWriteGuard};

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct Foo(u32);

let lock = Arc::new(RwLock::new(Foo(1)));

{
    let guard = Arc::clone(&lock).write_owned().await;
    let mut guard = OwnedRwLockWriteGuard::try_map(guard, |f| Some(&mut f.0)).expect("should not fail");
    *guard = 2;
}

assert_eq!(Foo(2), *lock.read().await);

Trait Implementations

Formats the value using the given formatter. Read more
The resulting type after dereferencing.
Dereferences the value.
Mutably dereferences the value.
Formats the value using the given formatter. Read more
Executes the destructor for this type. Read more

Auto Trait Implementations

Blanket Implementations

A guard object containing the value and keeping it alive. Read more
The loading method. Read more
Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
The equivalent of Access::load.

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.