Struct MappedMutexGuard 

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

An RAII mutex guard returned by MutexGuard::map, which can point to a subfield of the protected data.

The main difference between MappedMutexGuard and MutexGuard 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 MutexGuard.

Implementations

impl<'a, R: RawMutex + 'a, T: ?Sized + 'a> MappedMutexGuard<'a, R, T>

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

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

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

This is an associated function that needs to be used as MappedMutexGuard::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<MappedMutexGuard<'a, R, U>, Self>

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

Attempts to make a new MappedMutexGuard 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 MappedMutexGuard::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<MappedMutexGuard<'a, R, U>, (Self, E)>

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

Attempts to make a new MappedMutexGuard 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 MappedMutexGuard::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: RawMutexFair + 'a, T: ?Sized + 'a> MappedMutexGuard<'a, R, T>

pub fn unlock_fair(s: Self)

Unlocks the mutex using a fair unlock protocol.

A fair unlock hands the mutex directly to a waiting thread instead of allowing another thread to steal it. This can prevent starvation, but may reduce throughput by forcing a context switch.

Trait Implementations

impl<'a, R: RawMutex + 'a, T: Debug + ?Sized + 'a> Debug for MappedMutexGuard<'a, R, T>

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

Formats the value using the given formatter.

impl<'a, R: RawMutex + 'a, T: ?Sized + 'a> Deref for MappedMutexGuard<'a, R, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<'a, R: RawMutex + 'a, T: ?Sized + 'a> DerefMut for MappedMutexGuard<'a, R, T>

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

Mutably dereferences the value.

impl<'a, R: RawMutex + 'a, T: Display + ?Sized + 'a> Display for MappedMutexGuard<'a, R, T>

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

Formats the value using the given formatter.

impl<'a, R: RawMutex + 'a, T: ?Sized + 'a> Drop for MappedMutexGuard<'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.