Struct SharedCow

pub struct SharedCow<T: Clone>(/* private fields */);

A container that transparently shares a value when possible, but clones on mutate.

Unlike Arc, this is only intended to help save memory usage and reduce the amount of effort required to clone unmodified values with easy to use copy-on-write.

This should more or less reflect the API of std::borrow::Cow as much as is sensible.

Implementations

impl<T: Clone> SharedCow<T>

pub fn new(value: T) -> SharedCow<T>

Create a new Shared value.

pub fn into_owned(self: SharedCow<T>) -> T

Take an exclusive clone of the shared value, or move and take ownership if it wasn’t shared.

pub fn to_mut(&mut self) -> &mut T

Get a mutable reference to the value inside the SharedCow. This will result in a clone being created only if the value was shared with multiple references.

pub fn into_arc(value: SharedCow<T>) -> Arc<T>

Convert the Shared value into an Arc

pub fn ref_count(value: &SharedCow<T>) -> usize

Return the number of references to the shared value.

Trait Implementations

impl<T: Clone + Clone> Clone for SharedCow<T>

fn clone(&self) -> SharedCow<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Debug for SharedCow<T>

where T: Debug + Clone,

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

Formats the value using the given formatter.

impl<T: Default + Clone> Default for SharedCow<T>

fn default() -> SharedCow<T>

Returns the “default value” for a type.

impl<T: Clone> Deref for SharedCow<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'de, T> Deserialize<'de> for SharedCow<T>

where T: Deserialize<'de> + Clone,

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> Display for SharedCow<T>

where T: Display + Clone,

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

Formats the value using the given formatter.

impl<T> From<Arc<T>> for SharedCow<T>

where T: Clone,

fn from(value: Arc<T>) -> Self

Converts to this type from the input type.

impl<T> From<T> for SharedCow<T>

where T: Clone,

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: Hash + Clone> Hash for SharedCow<T>

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, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: Ord + Clone> Ord for SharedCow<T>

fn cmp(&self, other: &SharedCow<T>) -> Ordering

This method returns an Ordering between self and other.

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

where Self: Sized,

Compares and returns the maximum of two values.

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

where Self: Sized,

Compares and returns the minimum of two values.

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

where Self: Sized,

Restrict a value to a certain interval.

impl<T: PartialEq + Clone> PartialEq for SharedCow<T>

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialOrd + Clone> PartialOrd for SharedCow<T>

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

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

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

Tests less than (for self and other) and is used by the < operator.

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

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

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

Tests greater than (for self and other) and is used by the > operator.

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

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

impl<T> Serialize for SharedCow<T>

where T: Serialize + Clone,

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<T: Eq + Clone> Eq for SharedCow<T>

impl<T: Clone> StructuralPartialEq for SharedCow<T>