Struct RwLockReadGuard 

pub struct RwLockReadGuard<'rwlock, T: ?Sized + 'rwlock> {
    data: NonNull<T>,
    inner_lock: &'rwlock RwLock,
}

🔬This is a nightly-only experimental API. (nonpoison_rwlock #134645)

RAII structure used to release the shared read access of a lock when dropped.

This structure is created by the read and try_read methods on RwLock.

Fields

data: NonNull<T>

🔬This is a nightly-only experimental API. (nonpoison_rwlock #134645)

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 RwLockReadGuard instance only holds immutability until it drops, not for its whole scope. NonNull is preferable over *const T to allow for niche optimizations. NonNull is also covariant over T, just like we would have with &T.

inner_lock: &'rwlock RwLock

🔬This is a nightly-only experimental API. (nonpoison_rwlock #134645)

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

Implementations

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

unsafe fn new(lock: &'rwlock RwLock<T>) -> RwLockReadGuard<'rwlock, T>

🔬This is a nightly-only experimental API. (sync_nonpoison #134645)

Creates a new instance of RwLockReadGuard<T> from a RwLock<T>.

Safety

This function is safe if and only if the same thread has successfully and safely called lock.inner.read(), lock.inner.try_read(), or lock.inner.downgrade() before instantiating this object.

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

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

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

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

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

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 RwLockReadGuard 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<MappedRwLockReadGuard<'rwlock, U>, Self>

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

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

Makes a MappedRwLockReadGuard 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 reading, so this cannot fail.

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

Panics

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

Trait Implementations

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

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

Formats the value using the given formatter.

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

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

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

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

Formats the value using the given formatter.

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

fn drop(&mut self)

Executes the destructor for this type.

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

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