Struct MappedRwLockWriteGuard 

pub struct MappedRwLockWriteGuard<'rwlock, T: ?Sized + 'rwlock> {
    data: NonNull<T>,
    _variance: PhantomData<&'rwlock mut T>,
    inner_lock: &'rwlock RwLock,
}

🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

RAII structure used to release the exclusive write access of a lock when dropped, which can point to a subfield of the protected data.

This structure is created by the map and filter_map methods on RwLockWriteGuard.

Fields

data: NonNull<T>

🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

A pointer to the data protected by the RwLock. Note that we use a pointer here instead of &'rwlock T to avoid noalias violations, because a MappedRwLockWriteGuard instance only holds uniquneness until it drops, not for its whole scope. NonNull is preferable over *const T to allow for niche optimizations.

_variance: PhantomData<&'rwlock mut T>

🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

NonNull is covariant over T, so we add a PhantomData<&'rwlock mut T> field here to enforce the correct invariance over T.

inner_lock: &'rwlock RwLock

🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

A reference to the internal sys::RwLock that we have write-locked.

Implementations

impl<'rwlock, T: ?Sized> MappedRwLockWriteGuard<'rwlock, T>

pub fn map<U, F>(orig: Self, f: F) -> MappedRwLockWriteGuard<'rwlock, U>

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

🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

Makes a MappedRwLockWriteGuard for a component of the borrowed data, e.g. an enum variant.

The RwLock is already locked for writing, so this cannot fail.

This is an associated function that needs to be used as MappedRwLockWriteGuard::map(...). A method would interfere with methods of the same name on the contents of the MappedRwLockWriteGuard used through Deref.

Panics

If the closure panics, the guard will be dropped (unlocked).

pub fn filter_map<U, F>( orig: Self, f: F, ) -> Result<MappedRwLockWriteGuard<'rwlock, U>, Self>

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

🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

Makes a MappedRwLockWriteGuard for a component of the borrowed data. The original guard is returned as an Err(...) if the closure returns None.

The RwLock is already locked for writing, so this cannot fail.

This is an associated function that needs to be used as MappedRwLockWriteGuard::filter_map(...). A method would interfere with methods of the same name on the contents of the MappedRwLockWriteGuard used through Deref.

Panics

If the closure panics, the guard will be dropped (unlocked).

Trait Implementations

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

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

Formats the value using the given formatter.

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

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

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

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

Mutably dereferences the value.

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

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

Formats the value using the given formatter.

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

fn drop(&mut self)

Executes the destructor for this type.

impl<T: ?Sized> !Send for MappedRwLockWriteGuard<'_, T>

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