[−][src]Struct reffers::aref::ARef
ARef - a reference that abstracts the owner completely.
ARef takes over where OwningRef ends, by abstracting the owner even further.
This makes it possible to return, say, an ARef<str>
and have the caller drop the owner
when done looking at it, without having to bother about whether the owner is a String
, Rc<String>
, a
Ref<String>
, or something else.
If you want an ARef that's restricted to Send types, use ARefs, and if you want an ARef that's restricted to Send + Sync types, use ARefss.
Oh, and it's repr(C), so it can be transferred over an FFI boundary (if its target is repr(C), too).
Example
use std::rc::Rc; use reffers::ARef; struct CountDown(pub Rc<String>); impl CountDown { pub fn idx_to_str(&self, idx: u32) -> ARef<str> { match idx { 0 => "Go!".into(), // We clone the Rc instead of the String // for performance, // then we map from &String to &str 1 => ARef::new(self.0.clone()).map(|s| &**s), _ => format!("{}...", idx).into(), } } } let c = CountDown(Rc::new("Ready!".into())); assert_eq!(&*c.idx_to_str(3), "3..."); assert_eq!(&*c.idx_to_str(2), "2..."); assert_eq!(&*c.idx_to_str(1), "Ready!"); assert_eq!(&*c.idx_to_str(0), "Go!");
Methods
impl<'a, U: Descend> ARef<'a, U>
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pub fn descend_from(x: Self) -> ARef<'a, <U::Inner as Deref>::Target>
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Descends from a ARef<RefCell
Example
use std::sync::{Arc, RwLock}; use reffers::ARef; let x = Arc::new(RwLock::new("Hello!")); { let aref = ARef::new(x.clone()); let hello = ARef::descend_from(aref); // The RwLock is now read locked assert_eq!(*hello, "Hello!"); assert!(x.try_write().is_err()); } // The lock is released when the ARef goes out of scope assert!(x.try_write().is_ok());
pub fn try_descend_from(
x: Self
) -> Result<ARef<'a, <U::Inner as Deref>::Target>, Self>
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x: Self
) -> Result<ARef<'a, <U::Inner as Deref>::Target>, Self>
Descends from a ARef<RefCell
Fails if the RefCell/RwLock/Mutex is busy (or poisoned).
impl<'a, U: ?Sized> ARef<'a, U>
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pub fn new<O>(owner: O) -> Self where
O: 'a + AReffic + Deref<Target = U>,
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O: 'a + AReffic + Deref<Target = U>,
Creates a new ARef from what the ARef points to.
Example
use std::rc::Rc; use reffers::ARef; let aref = ARef::new(Rc::new(43)); assert_eq!(*aref, 43);
pub fn map<V: ?Sized, F: FnOnce(&U) -> &V>(self, f: F) -> ARef<'a, V>
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Maps the ARef's target to something reachable from the target.
Example
use reffers::ARef; let aref: ARef<[u8]> = vec![0u8, 5, 7].into(); assert_eq!(*aref.map(|s| &s[1]), 5);
pub fn try_map<E, V: ?Sized, F: FnOnce(&U) -> Result<&V, E>>(
self,
f: F
) -> Result<ARef<'a, V>, E>
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self,
f: F
) -> Result<ARef<'a, V>, E>
Like map, but with Result passthrough.
Example
use reffers::ARef; let aref = ARef::<[u8]>::from(vec![0u8, 5, 7]); assert_eq!(aref.try_map(|s| s.get(9).ok_or(())), Err(()));
Trait Implementations
impl<'a, U: ?Sized> Drop for ARef<'a, U>
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impl<'a, U: ?Sized> AsRef<U> for ARef<'a, U>
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impl<'a, O: 'a + AReffic + Deref<Target = U>, U: ?Sized> From<O> for ARef<'a, U>
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impl<'a, U: ?Sized + Eq> Eq for ARef<'a, U>
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impl<'a, U: ?Sized + Ord> Ord for ARef<'a, U>
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fn cmp(&self, other: &Self) -> Ordering
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fn max(self, other: Self) -> Self
1.21.0[src]
fn min(self, other: Self) -> Self
1.21.0[src]
fn clamp(self, min: Self, max: Self) -> Self
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impl<'a, U: ?Sized + PartialEq> PartialEq<ARef<'a, U>> for ARef<'a, U>
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impl<'a, U: ?Sized + PartialOrd> PartialOrd<ARef<'a, U>> for ARef<'a, U>
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fn partial_cmp(&self, other: &Self) -> Option<Ordering>
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fn lt(&self, other: &Self) -> bool
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fn le(&self, other: &Self) -> bool
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fn gt(&self, other: &Self) -> bool
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fn ge(&self, other: &Self) -> bool
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impl<'a, U: Debug + ?Sized> Debug for ARef<'a, U>
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impl<'a, U: ?Sized> Deref for ARef<'a, U>
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impl<'a, U: ?Sized + Hash> Hash for ARef<'a, U>
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fn hash<H>(&self, state: &mut H) where
H: Hasher,
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H: Hasher,
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
impl<'a, U: ?Sized> Borrow<U> for ARef<'a, U>
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Auto Trait Implementations
impl<'a, U> !Send for ARef<'a, U>
impl<'a, U> !Sync for ARef<'a, U>
impl<'a, U: ?Sized> Unpin for ARef<'a, U>
impl<'a, U: ?Sized> UnwindSafe for ARef<'a, U> where
U: RefUnwindSafe,
U: RefUnwindSafe,
impl<'a, U> !RefUnwindSafe for ARef<'a, U>
Blanket Implementations
impl<T> Repr for T
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type Store = T
fn convert(*mut T) -> *mut T
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unsafe fn deallocate_mem<M>(&mut UnsafeCell<RCell<<T as Repr>::Store, M>>) where
M: BitMask,
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M: BitMask,
impl<T> Repr for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryFrom<U> 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, U> TryInto<U> 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.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,