Struct internment::ArcIntern

pub struct ArcIntern<T: Eq + Hash + Send + Sync + 'static> { /* private fields */ }

A pointer to a reference-counted interned object.

This type requires feature “arc”. The interned object will be held in memory only until its reference count reaches zero.

Example

use internment::ArcIntern;

let x = ArcIntern::new("hello");
let y = ArcIntern::new("world");
assert_ne!(x, y);
assert_eq!(x, ArcIntern::new("hello"));
assert_eq!(*x, "hello"); // dereference an ArcIntern like a pointer

Example with owned String data

use internment::ArcIntern;

let x = ArcIntern::new("hello".to_string());
let y = ArcIntern::<String>::from("world");
assert_eq!(x, ArcIntern::from("hello"));
assert_eq!(&*x, "hello"); // dereference an ArcIntern like a pointer

Implementations

impl<T: Eq + Hash + Send + Sync + 'static> ArcIntern<T>

pub fn new(val: T) -> ArcIntern<T>

Intern a value. If this value has not previously been interned, then new will allocate a spot for the value on the heap. Otherwise, it will return a pointer to the object previously allocated.

Note that ArcIntern::new is a bit slow, since it needs to check a DashMap which is protected by internal sharded locks.

pub fn from<'a, Q: ?Sized + Eq + Hash + 'a>(val: &'a Q) -> ArcIntern<T> where
    T: Borrow<Q> + From<&'a Q>, 

Intern a value from a reference with atomic reference counting.

If this value has not previously been interned, then new will allocate a spot for the value on the heap and generate that value using T::from(val).

pub fn num_objects_interned() -> usize

See how many objects have been interned. This may be helpful in analyzing memory use.

pub fn refcount(&self) -> usize

Return the number of counts for this pointer.

Trait Implementations

impl<T: Send + Sync + Hash + Eq> AsRef<T> for ArcIntern<T>

fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.

impl<T: Eq + Hash + Send + Sync> Borrow<T> for ArcIntern<T>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T: Eq + Hash + Send + Sync + 'static> Clone for ArcIntern<T>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Eq + Hash + Send + Sync + Debug> Debug for ArcIntern<T>

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

Formats the value using the given formatter.

impl<T: Eq + Hash + Send + Sync + Default + 'static> Default for ArcIntern<T>

fn default() -> ArcIntern<T>

Returns the “default value” for a type.

impl<T: Eq + Hash + Send + Sync> Deref for ArcIntern<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T: Eq + Hash + Send + Sync + Display> Display for ArcIntern<T>

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

Formats the value using the given formatter.

impl<T: Eq + Hash + Send + Sync> Drop for ArcIntern<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T: Eq + Hash + Send + Sync + 'static> From<T> for ArcIntern<T>

fn from(t: T) -> Self

Converts to this type from the input type.

impl<T: Eq + Hash + Send + Sync> Hash for ArcIntern<T>

The hash implementation returns the hash of the pointer value, not the hash of the value pointed to. This should be irrelevant, since there is a unique pointer for every value, but it is observable, since you could compare the hash of the pointer with hash of the data itself.

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl<T: Eq + Hash + Send + Sync + Ord> Ord for ArcIntern<T>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl<T: Eq + Hash + Send + Sync> PartialEq<ArcIntern<T>> for ArcIntern<T>

fn eq(&self, other: &ArcIntern<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<T: Eq + Hash + Send + Sync + PartialOrd> PartialOrd<ArcIntern<T>> for ArcIntern<T>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Self) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Self) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Self) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Self) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: Eq + Hash + Send + Sync> Pointer for ArcIntern<T>

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

Formats the value using the given formatter.

impl<T: Eq + Hash + Send + Sync> Eq for ArcIntern<T>

impl<T: Eq + Hash + Send + Sync> Send for ArcIntern<T>

impl<T: Eq + Hash + Send + Sync> Sync for ArcIntern<T>