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Struct MappedRwLockReadGuard 

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

RAII structure used to release the shared read access of a lock when dropped, which can point to a subfield of the protected data.

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

Implementations

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

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

The RwLock is already locked for reading, so this cannot fail.

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 MappedRwLockReadGuard used through Deref.

Panics

If the closure panics, the guard will be dropped (unlocked) and the RwLock will not be poisoned.

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

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

The RwLock is already locked for reading, so this cannot fail.

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

Panics

If the closure panics, the guard will be dropped (unlocked) and the RwLock will not be poisoned.

Trait Implementations

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impl<T: ?Sized + Debug> Debug for MappedRwLockReadGuard<'_, 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 MappedRwLockReadGuard<'_, 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 + Display> Display for MappedRwLockReadGuard<'_, 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 MappedRwLockReadGuard<'_, 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 MappedRwLockReadGuard<'_, T>
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impl<T: ?Sized + Sync> Sync for MappedRwLockReadGuard<'_, T>

Auto Trait Implementations

impl<'rwlock, T> Freeze for MappedRwLockReadGuard<'rwlock, T>where
    T: ?Sized,
impl<'rwlock, T> RefUnwindSafe for MappedRwLockReadGuard<'rwlock, T>where
    T: RefUnwindSafe + ?Sized,
impl<'rwlock, T> Unpin for MappedRwLockReadGuard<'rwlock, T>where
    T: ?Sized,
impl<'rwlock, T> UnwindSafe for MappedRwLockReadGuard<'rwlock, T>where
    T: RefUnwindSafe + ?Sized,

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/poison/struct.MappedRwLockReadGuard.html