Struct RwLockWriteGuard 

pub struct RwLockWriteGuard<'a, T: ?Sized> { /* private fields */ }

Exclusive access to a RwLock’s value; releases on drop. The release makes the progress RwLockReadGuard’s does.

Implementations

impl<'a, T: ?Sized> RwLockWriteGuard<'a, T>

pub fn map<F, U>(this: Self, f: F) -> RwLockMappedWriteGuard<'a, U>

where U: ?Sized, F: FnOnce(&mut T) -> &mut U,

A guard for a component of the locked data. It cannot fail: this guard already holds the write.

An associated function, RwLockWriteGuard::map(guard, f): a method would shadow methods of the locked data.

pub fn downgrade_map<F, U>(this: Self, f: F) -> RwLockReadGuard<'a, U>

where U: ?Sized, F: FnOnce(&T) -> &U,

A read guard for a component of the locked data, made while the write is turned into a read in one step, as downgrade does. Inside f the write is still held, yet f is given only a &T: a &mut T could be kept past the downgrade through interior mutability.

pub fn try_map<F, U>( this: Self, f: F, ) -> Result<RwLockMappedWriteGuard<'a, U>, Self>

where U: ?Sized, F: FnOnce(&mut T) -> Option<&mut U>,

map that gives the guard back when f finds no component, with the write still held.

pub fn try_downgrade_map<F, U>( this: Self, f: F, ) -> Result<RwLockReadGuard<'a, U>, Self>

where U: ?Sized, F: FnOnce(&T) -> Option<&U>,

downgrade_map that gives the guard back when f finds no component: the lock is then neither released nor downgraded.

pub fn into_mapped(this: Self) -> RwLockMappedWriteGuard<'a, T>

This guard as a RwLockMappedWriteGuard, for a struct field that holds one. The same as RwLockWriteGuard::map(guard, |me| me).

pub fn downgrade(self) -> RwLockReadGuard<'a, T>

Turns the write into a read in one step, so no writer gets in between.

This does not necessarily let more readers in: a writer may be next in line. The readers queued behind a writer-free front share the lock now, and are woken to do so.

It makes the progress a release does (see RwLockReadGuard).

use nuclei::sync::RwLock;

let lock = RwLock::new(1);
let mut write = lock.try_write().expect("free");
*write += 1;
let read = write.downgrade();
assert_eq!(*read, 2);
assert!(lock.try_write().is_err(), "the read is still held");
assert!(lock.try_read().is_ok(), "readers share it");

Trait Implementations

impl<T: ?Sized + Debug> Debug for RwLockWriteGuard<'_, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: ?Sized> Deref for RwLockWriteGuard<'_, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T: ?Sized> DerefMut for RwLockWriteGuard<'_, T>

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<T: ?Sized + Display> Display for RwLockWriteGuard<'_, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: ?Sized> Drop for RwLockWriteGuard<'_, T>

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl<T: ?Sized + Send + Sync> Send for RwLockWriteGuard<'_, T>

impl<T: ?Sized + Send + Sync> Sync for RwLockWriteGuard<'_, T>