Struct MappedRwLockReadGuard 

pub struct MappedRwLockReadGuard<'a, R: RawRwLock, T: ?Sized + 'a> { /* private fields */ }

An RAII read lock guard returned by RwLockReadGuard::map, which can point to a subfield of the protected data.

The main difference between MappedRwLockReadGuard and RwLockReadGuard is that the former doesn’t support temporarily unlocking and re-locking, since that could introduce soundness issues if the locked object is modified by another thread.

This structure is created by the map and try_map, and try_map_or_err functions on RwLockReadGuard.

Implementations

impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> MappedRwLockReadGuard<'a, R, T>

pub fn map<U: ?Sized, F>(s: Self, f: F) -> MappedRwLockReadGuard<'a, R, U>

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

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

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

Panics

If f panics, the original guard is dropped.

pub fn try_map<U: ?Sized, F>( s: Self, f: F, ) -> Result<MappedRwLockReadGuard<'a, R, U>, Self>

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

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

This is an associated function that needs to be used as MappedRwLockReadGuard::try_map(...). A method would interfere with methods of the same name on the contents of the locked data.

Panics

If f panics, the original guard is dropped.

pub fn try_map_or_err<U: ?Sized, F, E>( s: Self, f: F, ) -> Result<MappedRwLockReadGuard<'a, R, U>, (Self, E)>

where F: FnOnce(&T) -> Result<&U, E>,

Attempts to make a new MappedRwLockReadGuard for a component of the locked data. The original guard is returned alongside arbitrary user data if the closure returns Err.

This is an associated function that needs to be used as MappedRwLockReadGuard::try_map_or_err(...). A method would interfere with methods of the same name on the contents of the locked data.

Panics

If f panics, the original guard is dropped.

impl<'a, R: RawRwLockFair + 'a, T: ?Sized + 'a> MappedRwLockReadGuard<'a, R, T>

pub fn unlock_fair(s: Self)

Unlocks the RwLock using a fair unlock protocol.

A fair unlock gives waiting threads priority over new acquisition attempts. This can prevent starvation, but may reduce throughput by forcing a context switch.

Trait Implementations

impl<'a, R: RawRwLock + 'a, T: Debug + ?Sized + 'a> Debug for MappedRwLockReadGuard<'a, R, T>

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

Formats the value using the given formatter.

impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Deref for MappedRwLockReadGuard<'a, R, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<'a, R: RawRwLock + 'a, T: Display + ?Sized + 'a> Display for MappedRwLockReadGuard<'a, R, T>

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

Formats the value using the given formatter.

impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Drop for MappedRwLockReadGuard<'a, R, 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.