futures_util::lock

Struct MappedMutexGuard

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

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.

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

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

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§

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

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

Formats the value using the given formatter. Read more
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impl<T: ?Sized, U: ?Sized> Deref for MappedMutexGuard<'_, T, U>

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type Target = U

The resulting type after dereferencing.
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fn deref(&self) -> &U

Dereferences the value.
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impl<T: ?Sized, U: ?Sized> DerefMut for MappedMutexGuard<'_, T, U>

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

Mutably dereferences the value.
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impl<T: ?Sized, U: ?Sized> Drop for MappedMutexGuard<'_, T, U>

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl<T: ?Sized + Send, U: ?Sized + Send> Send for MappedMutexGuard<'_, T, U>

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

Auto Trait Implementations§

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

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impl<'a, T, U> !RefUnwindSafe for MappedMutexGuard<'a, T, U>

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

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impl<'a, T, U> !UnwindSafe for MappedMutexGuard<'a, T, U>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.