1.0.0[][src]Struct rustc_data_structures::sync::Lrc

pub struct Lrc<T> where
    T: ?Sized
{ ptr: NonNull<RcBox<T>>, phantom: PhantomData<T>, }

A single-threaded reference-counting pointer. 'Rc' stands for 'Reference Counted'.

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(&mut value) instead of value.get_mut(). This avoids conflicts with methods of the inner type T.

Fields

Methods

impl<T> Rc<T>
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Constructs a new Rc<T>.

Examples

use std::rc::Rc;

let five = Rc::new(5);

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 = Rc::clone(&x);
assert_eq!(*Rc::try_unwrap(x).unwrap_err(), 4);

impl<T> Rc<T> where
    T: ?Sized
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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);

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!

Creates a new Weak pointer to this value.

Examples

use std::rc::Rc;

let five = Rc::new(5);

let weak_five = Rc::downgrade(&five);

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));

Gets the number of strong (Rc) pointers to this value.

Examples

use std::rc::Rc;

let five = Rc::new(5);
let _also_five = Rc::clone(&five);

assert_eq!(2, Rc::strong_count(&five));

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 = Rc::clone(&x);
assert!(Rc::get_mut(&mut x).is_none());

Returns true if the two Rcs 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 = Rc::clone(&five);
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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Important traits for &'a mut R

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 = Rc::clone(&data);    // 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);

impl Rc<Any + 'static>
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Attempt to downcast the Rc<Any> to a concrete type.

Examples

use std::any::Any;
use std::rc::Rc;

fn print_if_string(value: Rc<Any>) {
    if let Ok(string) = value.downcast::<String>() {
        println!("String ({}): {}", string.len(), string);
    }
}

fn main() {
    let my_string = "Hello World".to_string();
    print_if_string(Rc::new(my_string));
    print_if_string(Rc::new(0i8));
}

impl<T> Rc<T> where
    T: ?Sized
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impl<T> Rc<[T]>
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Trait Implementations

impl<'a> From<&'a Path> for Rc<Path>
1.24.0
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Performs the conversion.

impl<'a> From<&'a OsStr> for Rc<OsStr>
1.24.0
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Performs the conversion.

impl From<PathBuf> for Rc<Path>
1.24.0
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Performs the conversion.

impl From<OsString> for Rc<OsStr>
1.24.0
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Converts a OsString into a Rc<OsStr> without copying or allocating.

impl From<CString> for Rc<CStr>
1.24.0
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Converts a CString into a Rc<CStr> without copying or allocating.

impl<'a> From<&'a CStr> for Rc<CStr>
1.24.0
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Performs the conversion.

impl<T> UnwindSafe for Rc<T> where
    T: RefUnwindSafe + ?Sized
1.9.0
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impl<T> PartialOrd<Rc<T>> for Rc<T> where
    T: PartialOrd<T> + ?Sized
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Partial comparison for two Rcs.

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)));

Less-than comparison for two Rcs.

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));

'Less than or equal to' comparison for two Rcs.

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));

Greater-than comparison for two Rcs.

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));

'Greater than or equal to' comparison for two Rcs.

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> Drop for Rc<T> where
    T: ?Sized
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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 = Rc::clone(&foo);

drop(foo);    // Doesn't print anything
drop(foo2);   // Prints "dropped!"

impl<T> AsRef<T> for Rc<T> where
    T: ?Sized
1.5.0
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Important traits for &'a mut R

Performs the conversion.

impl<T> Eq for Rc<T> where
    T: Eq + ?Sized
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impl<T> Deref for Rc<T> where
    T: ?Sized
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The resulting type after dereferencing.

Important traits for &'a mut R

Dereferences the value.

impl<T> Borrow<T> for Rc<T> where
    T: ?Sized
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Important traits for &'a mut R

Immutably borrows from an owned value. Read more

impl<T> !Sync for Rc<T> where
    T: ?Sized
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impl<T> !Send for Rc<T> where
    T: ?Sized
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impl<T> Default for Rc<T> where
    T: Default
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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> Unpin for Rc<T> where
    T: ?Sized
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impl<T> Display for Rc<T> where
    T: Display + ?Sized
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Formats the value using the given formatter. Read more

impl<T> From<Vec<T>> for Rc<[T]>
1.21.0
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Performs the conversion.

impl From<String> for Rc<str>
1.21.0
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Performs the conversion.

impl<T> From<Box<T>> for Rc<T> where
    T: ?Sized
1.21.0
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Performs the conversion.

impl<'a> From<&'a str> for Rc<str>
1.21.0
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Performs the conversion.

impl<'a, T> From<&'a [T]> for Rc<[T]> where
    T: Clone
1.21.0
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Performs the conversion.

impl<T> From<T> for Rc<T>
1.6.0
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Performs the conversion.

impl<T> Clone for Rc<T> where
    T: ?Sized
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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);

Rc::clone(&five);

Performs copy-assignment from source. Read more

impl<T> Hash for Rc<T> where
    T: Hash + ?Sized
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Feeds this value into the given [Hasher]. Read more

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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Formats the value using the given formatter. Read more

impl<T, U> CoerceUnsized<Rc<U>> for Rc<T> where
    T: Unsize<U> + ?Sized,
    U: ?Sized
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impl<T> PartialEq<Rc<T>> for Rc<T> where
    T: PartialEq<T> + ?Sized
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Equality for two Rcs.

Two Rcs are equal if their inner values are equal.

Examples

use std::rc::Rc;

let five = Rc::new(5);

assert!(five == Rc::new(5));

Inequality for two Rcs.

Two Rcs 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> Ord for Rc<T> where
    T: Ord + ?Sized
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Comparison for two Rcs.

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)));

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

impl<T> Pointer for Rc<T> where
    T: ?Sized
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Formats the value using the given formatter.

impl<T> Decodable for Rc<T> where
    T: Decodable
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<T> Decodable for Rc<[T]> where
    T: Decodable
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<T> Encodable for Rc<T> where
    T: Encodable
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<T> Encodable for Rc<[T]> where
    T: Encodable
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<'a, T> IntoErased<'a> for Rc<T> where
    T: 'a, 

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Owner with the dereference type substituted to Erased.

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Perform the type erasure.

impl<T> StableDeref for Rc<T> where
    T: ?Sized

impl<T> CloneStableDeref for Rc<T> where
    T: ?Sized

impl<'a, T: 'a> IntoErased<'a> for Rc<T>
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Owner with the dereference type substituted to Erased.

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Perform the type erasure.

impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for Rc<T>
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Blanket Implementations

impl<T> Erased for T
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impl<T> Send for T where
    T: ?Sized
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impl<T> Sync for T where
    T: ?Sized
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impl<T> ToOwned for T where
    T: Clone
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Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

impl<T> From for T
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Performs the conversion.

impl<T> ToString for T where
    T: Display + ?Sized
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Converts the given value to a String. Read more

impl<T, U> Into for T where
    U: From<T>, 
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Performs the conversion.

impl<T, U> TryFrom for T where
    T: From<U>, 
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🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from)

Performs the conversion.

impl<T> Borrow for T where
    T: ?Sized
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Important traits for &'a mut R

Immutably borrows from an owned value. Read more

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
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🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from)

Performs the conversion.

impl<T> BorrowMut for T where
    T: ?Sized
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Important traits for &'a mut R

Mutably borrows from an owned value. Read more

impl<T> Any for T where
    T: 'static + ?Sized
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🔬 This is a nightly-only experimental API. (get_type_id)

this method will likely be replaced by an associated static

Gets the TypeId of self. Read more

impl<T> Encodable for T where
    T: UseSpecializedEncodable + ?Sized
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<T> Decodable for T where
    T: UseSpecializedDecodable
[src]

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

impl<E> SpecializationError for E
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🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Create an error for a missing method specialization. Defaults to panicking with type, trait & method names. S is the encoder/decoder state type, T is the type being encoded/decoded, and the arguments are the names of the trait and method that should've been overridden. Read more

impl<T> Erased for T