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

A guard that releases the upgradable read lock when dropped.

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impl<'a, T> RwLockUpgradableReadGuard<'a, T>
where T: ?Sized,

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pub fn downgrade( guard: RwLockUpgradableReadGuard<'a, T> ) -> RwLockReadGuard<'a, T>

Downgrades into a regular reader guard.

Examples
use async_lock::{RwLock, RwLockUpgradableReadGuard};

let lock = RwLock::new(1);

let reader = lock.upgradable_read().await;
assert_eq!(*reader, 1);

assert!(lock.try_upgradable_read().is_none());

let reader = RwLockUpgradableReadGuard::downgrade(reader);

assert!(lock.try_upgradable_read().is_some());
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pub fn try_upgrade( guard: RwLockUpgradableReadGuard<'a, T> ) -> Result<RwLockWriteGuard<'a, T>, RwLockUpgradableReadGuard<'a, T>>

Attempts to upgrade into a write lock.

If a write lock could not be acquired at this time, then None is returned. Otherwise, an upgraded guard is returned that releases the write lock when dropped.

This function can only fail if there are other active read locks.

Examples
use async_lock::{RwLock, RwLockUpgradableReadGuard};

let lock = RwLock::new(1);

let reader = lock.upgradable_read().await;
assert_eq!(*reader, 1);

let reader2 = lock.read().await;
let reader = RwLockUpgradableReadGuard::try_upgrade(reader).unwrap_err();

drop(reader2);
let writer = RwLockUpgradableReadGuard::try_upgrade(reader).unwrap();
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pub async fn upgrade( guard: RwLockUpgradableReadGuard<'a, T> ) -> RwLockWriteGuard<'a, T>

Upgrades into a write lock.

Examples
use async_lock::{RwLock, RwLockUpgradableReadGuard};

let lock = RwLock::new(1);

let reader = lock.upgradable_read().await;
assert_eq!(*reader, 1);

let mut writer = RwLockUpgradableReadGuard::upgrade(reader).await;
*writer = 2;

Trait Implementations§

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

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

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

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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> Display for RwLockUpgradableReadGuard<'_, T>
where T: Display + ?Sized,

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

Formats the value using the given formatter. Read more
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impl<T> Send for RwLockUpgradableReadGuard<'_, T>
where T: Send + Sync + ?Sized,

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

Auto Trait Implementations§

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impl<'a, T> !RefUnwindSafe for RwLockUpgradableReadGuard<'a, T>

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impl<'a, T: ?Sized> Unpin for RwLockUpgradableReadGuard<'a, T>

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impl<'a, T> !UnwindSafe for RwLockUpgradableReadGuard<'a, T>

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> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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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.