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Struct MappedMutexGuard 

pub struct MappedMutexGuard<'a, T: ?Sized + 'a> { /* private fields */ }
🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

An RAII mutex guard returned by MutexGuard::map, which can point to a subfield of the protected data. When this structure is dropped (falls out of scope), the lock will be unlocked.

The main difference between MappedMutexGuard and MutexGuard is that the former cannot be used with Condvar, since that could introduce soundness issues if the locked object is modified by another thread while the Mutex is unlocked.

The data protected by the mutex can be accessed through this guard via its Deref and DerefMut implementations.

This structure is created by the map and filter_map methods on MutexGuard.

Implementations

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impl<'a, T: ?Sized> MappedMutexGuard<'a, T>
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pub fn map<U, F>(orig: Self, f: F) -> MappedMutexGuard<'a, U>where
    F: FnOnce(&mut T) -> &mut U,
    U: ?Sized,
🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

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

The Mutex is already locked, so this cannot fail.

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 MutexGuard used through Deref.

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pub fn filter_map<U, F>(
    orig: Self,
    f: F,
) -> Result<MappedMutexGuard<'a, U>, Self>where
    F: FnOnce(&mut T) -> Option<&mut U>,
    U: ?Sized,
🔬This is a nightly-only experimental API. (mapped_lock_guards #117108)

Makes a MappedMutexGuard for a component of the borrowed data. The original guard is returned as an Err(...) if the closure returns None.

The Mutex is already locked, so this cannot fail.

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

Trait Implementations

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impl<T: ?Sized + Debug> Debug for MappedMutexGuard<'_, T>
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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> Deref for MappedMutexGuard<'_, T>
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type Target = T
The resulting type after dereferencing.
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fn deref(&self) -> &T
Dereferences the value.
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impl<T: ?Sized> DerefMut for MappedMutexGuard<'_, T>
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fn deref_mut(&mut self) -> &mut T
Mutably dereferences the value.
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impl<T: ?Sized + Display> Display for MappedMutexGuard<'_, T>
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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> Drop for MappedMutexGuard<'_, T>
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fn drop(&mut self)
Executes the destructor for this type. Read more
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impl<T: ?Sized> !Send for MappedMutexGuard<'_, T>
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impl<T: ?Sized + Sync> Sync for MappedMutexGuard<'_, T>

Auto Trait Implementations

impl<'a, T> Freeze for MappedMutexGuard<'a, T>where
    T: ?Sized,
impl<'a, T> RefUnwindSafe for MappedMutexGuard<'a, T>where
    T: RefUnwindSafe + ?Sized,
impl<'a, T> Unpin for MappedMutexGuard<'a, T>where
    T: ?Sized,
impl<'a, T> !UnwindSafe for MappedMutexGuard<'a, T>

Blanket Implementations

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impl<T> Any for Twhere
    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 Twhere
    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 Twhere
    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 Twhere
    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<P, T> Receiver for Pwhere
    P: Deref<Target = T> + ?Sized,
    T: ?Sized,
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type Target = T
🔬This is a nightly-only experimental API. (arbitrary_self_types #44874)
The target type on which the method may be called.
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impl<T> ToString for Twhere
    T: Display + ?Sized,
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fn to_string(&self) -> String
Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for Twhere
    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 Twhere
    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.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/sync/nonpoison/struct.MappedMutexGuard.html