Struct futures::lock::MappedMutexGuard

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

An RAII guard returned by the MutexGuard::map and MappedMutexGuard::map methods. When this structure is dropped (falls out of scope), the lock will be unlocked.

Implementations

impl<'a, T, U> MappedMutexGuard<'a, T, U>where
    T: ?Sized,
    U: ?Sized,

pub fn map<V, F>(
    this: MappedMutexGuard<'a, T, U>,
    f: F
) -> MappedMutexGuard<'a, T, V>where
    F: FnOnce(&mut U) -> &mut V,
    V: ?Sized,

Returns a locked view over a portion of the locked data.

Example

use futures::lock::{MappedMutexGuard, Mutex, MutexGuard};

let data = Mutex::new(Some("value".to_string()));
{
    let locked_str = MutexGuard::map(data.lock().await, |opt| opt.as_mut().unwrap());
    let locked_char = MappedMutexGuard::map(locked_str, |s| s.get_mut(0..1).unwrap());
    assert_eq!(&*locked_char, "v");
}

Trait Implementations

impl<T, U> Debug for MappedMutexGuard<'_, T, U>where
    U: Debug + ?Sized,
    T: ?Sized,

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

Formats the value using the given formatter.

impl<T, U> Deref for MappedMutexGuard<'_, T, U>where
    T: ?Sized,
    U: ?Sized,

type Target = U

The resulting type after dereferencing.

fn deref(&self) -> &U

Dereferences the value.

impl<T, U> DerefMut for MappedMutexGuard<'_, T, U>where
    T: ?Sized,
    U: ?Sized,

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

Mutably dereferences the value.

impl<T, U> Drop for MappedMutexGuard<'_, T, U>where
    T: ?Sized,
    U: ?Sized,

fn drop(&mut self)

Executes the destructor for this type.

impl<T, U> Send for MappedMutexGuard<'_, T, U>where
    T: Send + ?Sized,
    U: Send + ?Sized,

impl<T, U> Sync for MappedMutexGuard<'_, T, U>where
    T: Sync + ?Sized,
    U: Sync + ?Sized,