[−][src]Struct voluntary_servitude::atomics::FillOnceAtomicOption
Atomic abstraction of a Option<Box<T>>
that can provide access to a Option<&T>
This is ideal for a iterator or some consumer that doesn't actually consume the data
To make that possible the API is heavily limited (can only write to it through try_store
)
Methods
impl<T> FillOnceAtomicOption<T>
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pub fn new<V>(data: V) -> Self where
V: Into<Option<Box<T>>>,
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V: Into<Option<Box<T>>>,
Creates new FillOnceAtomicOption
use std::sync::atomic::Ordering; let empty: FillOnceAtomicOption<()> = FillOnceAtomicOption::new(None); assert_eq!(empty.get_ref(Ordering::Relaxed), None); let filled = FillOnceAtomicOption::new(Box::new(10)); assert_eq!(filled.get_ref(Ordering::Relaxed), Some(&10));
pub fn try_store<V>(&self, data: V, order: Ordering) -> Result<(), NotEmpty> where
V: Into<Box<T>>,
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V: Into<Box<T>>,
Stores new value if FillOnceAtomicOption
was not initialized (contains a None
)
This operation is implemented as a single atomic compare_and_swap
.
use std::sync::atomic::Ordering; let option = FillOnceAtomicOption::default(); let old = option.try_store(5, Ordering::Relaxed); assert!(old.is_ok()); assert_eq!(option.get_ref(Ordering::Relaxed), Some(&5)); let failed_to_store = option.try_store(10, Ordering::Relaxed); assert!(failed_to_store.is_err()); assert_eq!(option.get_ref(Ordering::Relaxed), Some(&5));
pub fn take(&mut self, order: Ordering) -> Option<Box<T>>
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Replaces FillOnceAtomicOption
value with None
returning old value
As opposed to take
from AtomicOption
use std::sync::atomic::Ordering; let mut option = FillOnceAtomicOption::from(5); assert_eq!(option.take(Ordering::Relaxed), Some(Box::new(5))); assert_eq!(option.take(Ordering::Relaxed), None);
impl<T: Copy> FillOnceAtomicOption<T>
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pub fn load(&self, order: Ordering) -> Option<T>
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Returns a copy of the wrapped T
use std::sync::atomic::Ordering; let empty: FillOnceAtomicOption<()> = FillOnceAtomicOption::new(None); assert_eq!(empty.load(Ordering::Relaxed), None); let filled = FillOnceAtomicOption::from(10); assert_eq!(filled.load(Ordering::Relaxed), Some(10));
impl<T> FillOnceAtomicOption<T>
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pub fn get_ref<'a>(&'a self, order: Ordering) -> Option<&'a T>
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Atomically extracts a reference to the element stored
use std::sync::atomic::Ordering; let empty: FillOnceAtomicOption<()> = FillOnceAtomicOption::new(None); assert_eq!(empty.get_ref(Ordering::Relaxed), None); let filled = FillOnceAtomicOption::from(10); assert_eq!(filled.get_ref(Ordering::Relaxed), Some(&10));
pub fn into_inner(self) -> Option<Box<T>>
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Converts itself into a Option<Box<T>>
let ten = FillOnceAtomicOption::from(10); assert_eq!(ten.into_inner().map(|a| *a), Some(10));
pub unsafe fn from_raw(ptr: *mut T) -> Self
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Creates new FillOnceAtomicOption
based on a raw pointer
Safety
Unsafe because it uses a raw pointer, so it can't be sure of its origin (and ownership)
You must own the pointer to call this
use std::{sync::atomic::Ordering, ptr::null_mut}; let empty = unsafe { FillOnceAtomicOption::<()>::from_raw(null_mut()) }; assert_eq!(empty.get_ref(Ordering::Relaxed), None); let filled = unsafe { FillOnceAtomicOption::from_raw(Box::into_raw(10.into())) }; assert_eq!(filled.get_ref(Ordering::Relaxed), Some(&10));
pub fn get_raw(&self, order: Ordering) -> *mut T
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Atomically extracts the stored pointer
If pointer returned is not null it's safe to deref as long as you don't drop the FillOnceAtomicOption
Safety
To deref it you must ensure that it's not null
, the FillOnceAtomicOption
wasn't dropped
Returns null
if FillOnceAtomicOption
is empty (was not initialized)
use std::{sync::atomic::Ordering, ptr::null_mut, ops::Deref}; let empty: FillOnceAtomicOption<()> = FillOnceAtomicOption::new(None); assert_eq!(empty.get_raw(Ordering::Relaxed), null_mut()); let filled = FillOnceAtomicOption::from(10); assert_eq!(unsafe { (&*filled.get_raw(Ordering::Relaxed)).deref() }, &10);
Trait Implementations
impl<T> Default for FillOnceAtomicOption<T>
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impl<T> From<FillOnceAtomicOption<T>> for AtomicOption<T>
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fn from(atomic: FillOnceAtomicOption<T>) -> Self
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impl<T> From<T> for FillOnceAtomicOption<T>
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impl<T> From<Box<T>> for FillOnceAtomicOption<T>
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impl<T> From<Option<T>> for FillOnceAtomicOption<T>
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impl<T> From<Option<Box<T>>> for FillOnceAtomicOption<T>
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impl<T> From<AtomicOption<T>> for FillOnceAtomicOption<T>
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fn from(atomic: AtomicOption<T>) -> Self
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impl<T> From<Atomic<T>> for FillOnceAtomicOption<T>
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impl<T: Debug> Debug for FillOnceAtomicOption<T>
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impl<T> Pointer for FillOnceAtomicOption<T>
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Auto Trait Implementations
impl<T> Send for FillOnceAtomicOption<T> where
T: Send,
T: Send,
impl<T> Sync for FillOnceAtomicOption<T> where
T: Sync,
T: Sync,
Blanket Implementations
impl<T, U> Into for T where
U: From<T>,
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U: From<T>,
impl<T> From for T
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impl<T, U> TryFrom for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T> Borrow for T where
T: ?Sized,
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T: ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> BorrowMut for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T, U> TryInto for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.