Struct adapton::macros::Rc 1.0.0
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pub struct Rc<T> where
T: ?Sized, { /* fields omitted */ }
A single-threaded reference-counting pointer.
See the module-level documentation for more details.
The inherent methods of Rc
are all associated functions, which means
that you have to call them as e.g. Rc::get_mut(&value)
instead of
value.get_mut()
. This avoids conflicts with methods of the inner
type T
.
Methods
impl<T> Rc<T>
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fn new(value: T) -> Rc<T>
fn try_unwrap(this: Rc<T>) -> Result<T, Rc<T>>
1.4.0
Returns the contained value, if the Rc
has exactly one strong reference.
Otherwise, an Err
is returned with the same Rc
that was
passed in.
This will succeed even if there are outstanding weak references.
Examples
use std::rc::Rc; let x = Rc::new(3); assert_eq!(Rc::try_unwrap(x), Ok(3)); let x = Rc::new(4); let _y = x.clone(); assert_eq!(*Rc::try_unwrap(x).unwrap_err(), 4);
fn into_raw(this: Rc<T>) -> *const T
1.17.0
Consumes the Rc
, returning the wrapped pointer.
To avoid a memory leak the pointer must be converted back to an Rc
using
Rc::from_raw
.
Examples
use std::rc::Rc; let x = Rc::new(10); let x_ptr = Rc::into_raw(x); assert_eq!(unsafe { *x_ptr }, 10);
unsafe fn from_raw(ptr: *const T) -> Rc<T>
1.17.0
Constructs an Rc
from a raw pointer.
The raw pointer must have been previously returned by a call to a
Rc::into_raw
.
This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.
Examples
use std::rc::Rc; let x = Rc::new(10); let x_ptr = Rc::into_raw(x); unsafe { // Convert back to an `Rc` to prevent leak. let x = Rc::from_raw(x_ptr); assert_eq!(*x, 10); // Further calls to `Rc::from_raw(x_ptr)` would be memory unsafe. } // The memory was freed when `x` went out of scope above, so `x_ptr` is now dangling!
impl<T> Rc<T> where
T: ?Sized,
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T: ?Sized,
fn downgrade(this: &Rc<T>) -> Weak<T>
1.4.0
Creates a new Weak
pointer to this value.
Examples
use std::rc::Rc; let five = Rc::new(5); let weak_five = Rc::downgrade(&five);
fn weak_count(this: &Rc<T>) -> usize
1.15.0
Gets the number of Weak
pointers to this value.
Examples
use std::rc::Rc; let five = Rc::new(5); let _weak_five = Rc::downgrade(&five); assert_eq!(1, Rc::weak_count(&five));
fn strong_count(this: &Rc<T>) -> usize
1.15.0
Gets the number of strong (Rc
) pointers to this value.
Examples
use std::rc::Rc; let five = Rc::new(5); let _also_five = five.clone(); assert_eq!(2, Rc::strong_count(&five));
fn get_mut(this: &mut Rc<T>) -> Option<&mut T>
1.4.0
Returns a mutable reference to the inner value, if there are
no other Rc
or Weak
pointers to the same value.
Returns None
otherwise, because it is not safe to
mutate a shared value.
See also make_mut
, which will clone
the inner value when it's shared.
Examples
use std::rc::Rc; let mut x = Rc::new(3); *Rc::get_mut(&mut x).unwrap() = 4; assert_eq!(*x, 4); let _y = x.clone(); assert!(Rc::get_mut(&mut x).is_none());
fn ptr_eq(this: &Rc<T>, other: &Rc<T>) -> bool
1.17.0
Returns true if the two Rc
s point to the same value (not
just values that compare as equal).
Examples
use std::rc::Rc; let five = Rc::new(5); let same_five = five.clone(); let other_five = Rc::new(5); assert!(Rc::ptr_eq(&five, &same_five)); assert!(!Rc::ptr_eq(&five, &other_five));
impl<T> Rc<T> where
T: Clone,
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T: Clone,
fn make_mut(this: &mut Rc<T>) -> &mut T
1.4.0
Makes a mutable reference into the given Rc
.
If there are other Rc
or Weak
pointers to the same value,
then make_mut
will invoke clone
on the inner value to
ensure unique ownership. This is also referred to as clone-on-write.
See also get_mut
, which will fail rather than cloning.
Examples
use std::rc::Rc; let mut data = Rc::new(5); *Rc::make_mut(&mut data) += 1; // Won't clone anything let mut other_data = data.clone(); // Won't clone inner data *Rc::make_mut(&mut data) += 1; // Clones inner data *Rc::make_mut(&mut data) += 1; // Won't clone anything *Rc::make_mut(&mut other_data) *= 2; // Won't clone anything // Now `data` and `other_data` point to different values. assert_eq!(*data, 8); assert_eq!(*other_data, 12);
Trait Implementations
impl<T> PartialOrd<Rc<T>> for Rc<T> where
T: PartialOrd<T> + ?Sized,
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T: PartialOrd<T> + ?Sized,
fn partial_cmp(&self, other: &Rc<T>) -> Option<Ordering>
Partial comparison for two Rc
s.
The two are compared by calling partial_cmp()
on their inner values.
Examples
use std::rc::Rc; use std::cmp::Ordering; let five = Rc::new(5); assert_eq!(Some(Ordering::Less), five.partial_cmp(&Rc::new(6)));
fn lt(&self, other: &Rc<T>) -> bool
Less-than comparison for two Rc
s.
The two are compared by calling <
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five < Rc::new(6));
fn le(&self, other: &Rc<T>) -> bool
'Less than or equal to' comparison for two Rc
s.
The two are compared by calling <=
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five <= Rc::new(5));
fn gt(&self, other: &Rc<T>) -> bool
Greater-than comparison for two Rc
s.
The two are compared by calling >
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five > Rc::new(4));
fn ge(&self, other: &Rc<T>) -> bool
'Greater than or equal to' comparison for two Rc
s.
The two are compared by calling >=
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five >= Rc::new(5));
impl<T> Ord for Rc<T> where
T: Ord + ?Sized,
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T: Ord + ?Sized,
fn cmp(&self, other: &Rc<T>) -> Ordering
Comparison for two Rc
s.
The two are compared by calling cmp()
on their inner values.
Examples
use std::rc::Rc; use std::cmp::Ordering; let five = Rc::new(5); assert_eq!(Ordering::Less, five.cmp(&Rc::new(6)));
impl<T> Eq for Rc<T> where
T: Eq + ?Sized,
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T: Eq + ?Sized,
impl<T> Drop for Rc<T> where
T: ?Sized,
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T: ?Sized,
fn drop(&mut self)
Drops the Rc
.
This will decrement the strong reference count. If the strong reference
count reaches zero then the only other references (if any) are
Weak
, so we drop
the inner value.
Examples
use std::rc::Rc; struct Foo; impl Drop for Foo { fn drop(&mut self) { println!("dropped!"); } } let foo = Rc::new(Foo); let foo2 = foo.clone(); drop(foo); // Doesn't print anything drop(foo2); // Prints "dropped!"
impl<T> From<T> for Rc<T>
1.6.0[src]
impl<T, U> CoerceUnsized<Rc<U>> for Rc<T> where
T: Unsize<U> + ?Sized,
U: ?Sized,
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T: Unsize<U> + ?Sized,
U: ?Sized,
impl<T> Pointer for Rc<T> where
T: ?Sized,
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T: ?Sized,
impl<T> Hash for Rc<T> where
T: Hash + ?Sized,
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T: Hash + ?Sized,
fn hash<H>(&self, state: &mut H) where
H: Hasher,
H: Hasher,
Feeds this value into the given [Hasher
]. Read more
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more
impl<T> Debug for Rc<T> where
T: Debug + ?Sized,
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T: Debug + ?Sized,
impl<T> Deref for Rc<T> where
T: ?Sized,
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T: ?Sized,
impl<T> PartialEq<Rc<T>> for Rc<T> where
T: PartialEq<T> + ?Sized,
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T: PartialEq<T> + ?Sized,
fn eq(&self, other: &Rc<T>) -> bool
Equality for two Rc
s.
Two Rc
s are equal if their inner values are equal.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five == Rc::new(5));
fn ne(&self, other: &Rc<T>) -> bool
Inequality for two Rc
s.
Two Rc
s are unequal if their inner values are unequal.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five != Rc::new(6));
impl<T> !Send for Rc<T> where
T: ?Sized,
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T: ?Sized,
impl<T> AsRef<T> for Rc<T> where
T: ?Sized,
1.5.0[src]
T: ?Sized,
fn as_ref(&self) -> &T
impl<T> !Sync for Rc<T> where
T: ?Sized,
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T: ?Sized,
impl<T> Clone for Rc<T> where
T: ?Sized,
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T: ?Sized,
fn clone(&self) -> Rc<T>
Makes a clone of the Rc
pointer.
This creates another pointer to the same inner value, increasing the strong reference count.
Examples
use std::rc::Rc; let five = Rc::new(5); five.clone();
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl<T> Borrow<T> for Rc<T> where
T: ?Sized,
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T: ?Sized,
fn borrow(&self) -> &T
impl<T> Display for Rc<T> where
T: Display + ?Sized,
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T: Display + ?Sized,
impl<T> Default for Rc<T> where
T: Default,
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T: Default,
fn default() -> Rc<T>
Creates a new Rc<T>
, with the Default
value for T
.
Examples
use std::rc::Rc; let x: Rc<i32> = Default::default(); assert_eq!(*x, 0);
impl<T> UnwindSafe for Rc<T> where
T: RefUnwindSafe + ?Sized,
1.9.0[src]
T: RefUnwindSafe + ?Sized,