Struct ArcInterner

pub struct ArcInterner<T: ?Sized>(/* private fields */);

An interner returning atomically reference-counted pointers to the interned data

Interned objects will be deallocated when there are no references to them any more and shrink_to_fit() is called on the interner

Example

use refcount_interner::ArcInterner;

let mut interner = ArcInterner::new();

let x = interner.intern(42);
let y = interner.intern(1337);

assert_eq!(*x, 42);
assert_ne!(x, y);
assert!(Arc::ptr_eq(&x, &interner.intern(42)));

Implementations

impl<T: ?Sized + Hash + Eq> ArcInterner<T>

pub fn new() -> ArcInterner<T>

Create a new, empty interner.

Example

let mut interner = ArcInterner::new();

pub fn try_intern(&self, t: &T) -> Option<Arc<T>>

Attempt to get a reference to an already interned object.

If the object has already been interned, an option containing a reference to the already interned object will be returned.

If the object has not yet been interned, None will be returned.

Example

let mut interner = ArcInterner::new();

let x = interner.intern(42);
assert_eq!(interner.try_intern(&42), Some(Arc::new(42)));
assert_eq!(interner.try_intern(&1337), None);

pub fn intern_boxed(&mut self, t: Box<T>) -> Arc<T>

Intern a boxed object

This method must be used to intern unsized types, since unsized types cannot be passed to intern(). The two most common unsized types, &[T] and &str can be interned with intern_slice() and intern_str() as well.

If the object has already been interned, the passed object will be dropped and deallocated, and a reference to the already interned object will be returned.

If the object has not yet been interned, the passed object will be moved into an Arc<T>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let x = Box::new(42);
let y = interner.intern_boxed(x);

assert_eq!(*y, 42);

pub fn shrink_to_fit(&mut self)

Deallocate all interned objects that are no longer referenced and shrink the internal storage to fit.

Example

let mut interner = ArcInterner::new();

let x = interner.intern(42);
let y = interner.intern(1337);
let z = y.clone();

drop(x);
drop(y);

interner.shrink_to_fit();
assert_eq!(interner.try_intern(&42), None);
assert_eq!(interner.try_intern(&1337), Some(Arc::new(1337)));

impl<T: Sized + Hash + Eq> ArcInterner<T>

pub fn intern(&mut self, t: T) -> Arc<T>

Intern an owned object

If the object has already been interned, the passed object will be dropped, and a reference to the already interned object will be returned.

If the object has not yet been interned, the passed object will be moved into an Arc<T>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let x = interner.intern(42);
let y = interner.intern(1337);

assert_eq!(*x, 42);
assert_ne!(x, y);
assert!(Arc::ptr_eq(&x, &interner.intern(42)));

impl<T: Sized + Hash + Eq + Clone> ArcInterner<T>

pub fn intern_cloned(&mut self, t: &T) -> Arc<T>

Intern a borrowed object, cloning if it has not yet been interned

If the object has already been interned, a reference to the already interned object will be returned.

If the object has not yet been interned, the passed object will be moved into an Arc<T>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let x = 42;
let y = interner.intern_cloned(&x);

assert_eq!(x, *y);

impl<T: Sized + Hash + Eq + Clone> ArcInterner<[T]>

pub fn intern_slice(&mut self, t: &[T]) -> Arc<[T]>

Intern a slice object

This method can be used to intern slices without boxing them.

If the slice has already been interned, a reference to the already interned slice will be returned.

If the slice has not yet been interned, the passed object will be cloned into an Arc<[T]>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let x = interner.intern_slice(&[1, 2, 3]);

assert_eq!(x.as_ref(), &[1, 2, 3]);

pub fn intern_vec(&mut self, t: Vec<T>) -> Arc<[T]>

Intern an owned vector

If the slice behind the vector has already been interned, a reference to the already / interned slice will be returned.

If the slice has not yet been interned, the passed vector will be moved into an Arc<[T]>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let v = vec![1, 2, 3];
let x = interner.intern_vec(v);

assert_eq!(x.as_ref(), &[1, 2, 3]);

impl ArcInterner<str>

pub fn intern_str(&mut self, t: &str) -> Arc<str>

Intern a string slice

This method can be used to intern string slices without boxing them.

If the string slice has already been interned, a reference to the already interned string slice will be returned.

If the string slice has not yet been interned, the passed object will be cloned into an Arc<str>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let x = interner.intern_str("hello");

assert_eq!(x.as_ref(), "hello");

pub fn intern_string(&mut self, t: String) -> Arc<str>

Intern an owned string

If the string has already been interned, a reference to the already interned string slice will be returned.

If the string has not yet been interned, the passed string will be moved into an Arc<str>, remembered for future calls to intern(), and returned.

Example

let mut interner = ArcInterner::new();

let s = String::from("hello");
let x = interner.intern_string(s);

assert_eq!(x.as_ref(), "hello");

Trait Implementations

impl<T: Debug + ?Sized> Debug for ArcInterner<T>

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

Formats the value using the given formatter.

impl<T: ?Sized> Default for ArcInterner<T>

fn default() -> ArcInterner<T>

Returns the “default value” for a type.