Enum cervine::Cow

pub enum Cow<'a, T, R: ?Sized> {
    Owned(T),
    Borrowed(&'a R),
}

Cow is a clone-on-write smart pointer largely analogous to alloc::borrow::Cow, with one key difference:
Instead of requiring ToOwned, the owned and borrowed type are both configurable and most methods require T: Borrow<R>.

serde::Deserialize and serde::Serialize are only available with the "serde" feature.

Variants

Owned(T)

Borrowed(&'a R)

Implementations

impl<'a, T: Borrow<R>, R: ?Sized> Cow<'a, T, R>

pub fn is_borrowed(&self) -> bool

Returns whether this value is a borrowed variant.

Example

use cervine::Cow;

let borrowed: Cow<String, _> = Cow::Borrowed("borrowed");
let owned: Cow<_, str> = Cow::Owned("owned".to_string());

assert!(borrowed.is_borrowed());
assert!(!owned.is_borrowed());

pub fn is_owned(&self) -> bool

Returns whether this value is an owned variant.

Example

use cervine::Cow;

let borrowed: Cow<String, _> = Cow::Borrowed("borrowed");
let owned: Cow<_, str> = Cow::Owned("owned".to_string());

assert!(!borrowed.is_owned());
assert!(owned.is_owned());

impl<'a, T: From<&'a R>, R: ?Sized> Cow<'a, T, R>

pub fn into_owned(self) -> T

Converts this value into T.

Example

use cervine::Cow;

let borrowed = Cow::Borrowed("borrowed");
let owned: Cow<_, str> = Cow::Owned("owned".into());

let not_borrowed: String = borrowed.into_owned(); // Clones the `String`.
let owned: String = owned.into_owned(); // Moves the `String`.

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

Retrieves a mutable reference to the contained T.

If this value is a borrowed variant, it is converted in place into an owned variant first.

Example

use cervine::Cow;

let mut borrowed = Cow::Borrowed("borrowed");
let mut owned: Cow<_, str> = Cow::Owned("owned".into());

let mutable_copy: &mut String = borrowed.make_mut(); // Clones the `String`.
let mutable_borrow: &mut String = owned.make_mut();

impl<'a, T: TryFrom<&'a R>, R: ?Sized> Cow<'a, T, R>

pub fn try_into_owned(self) -> Result<T, T::Error>

Converts this value into T if possible.

Example

use cervine::Cow;

let borrowed = Cow::Borrowed("borrowed");
let owned: Cow<_, str> = Cow::Owned("owned".into());

let not_borrowed: String = borrowed.try_into_owned()?; // Clones the `String`.
let owned: String = owned.try_into_owned()?; // Moves the `String`.

Errors

• <T as TryFrom<&'a R>>::Error: Returned iff this value is a borrowed variant and conversion into T fails.

pub fn try_make_mut(&mut self) -> Result<&mut T, T::Error>

Retrieves a mutable reference to the contained T, if possible.

If this value is a borrowed variant, an attempt is made to convert it in place into an owned variant first.

Example

use cervine::Cow;

let mut borrowed = Cow::Borrowed("borrowed");
let mut owned: Cow<_, str> = Cow::Owned("owned".into());

let mutable_copy: &mut String = borrowed.try_make_mut()?; // Clones the `String`.
let mutable_borrow: &mut String = owned.try_make_mut()?; // Moves the `String`.

Errors

• <T as TryFrom<&'a R>>::Error: Returned iff this value is a borrowed variant and conversion into the owned variant fails.

Trait Implementations

impl<'a, T: AsRef<R>, R: ?Sized> AsRef<R> for Cow<'a, T, R>

fn as_ref(&self) -> &R

Performs the conversion.

impl<'a, T: Borrow<R>, R: ?Sized> Borrow<R> for Cow<'a, T, R>

fn borrow(&self) -> &R

Immutably borrows from an owned value.

impl<'a, T: Clone, R: ?Sized> Clone for Cow<'a, T, R>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a, T: Copy, R: ?Sized> Copy for Cow<'a, T, R>

impl<'a, T: Debug, R: Debug + ?Sized> Debug for Cow<'a, T, R>

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

Formats the value using the given formatter.

impl<'a, T: Default, R: ?Sized> Default for Cow<'a, T, R>

fn default() -> Self

Returns the "default value" for a type.

impl<'a, T: Deref<Target = R>, R: ?Sized> Deref for Cow<'a, T, R>

type Target = R

The resulting type after dereferencing.

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

Dereferences the value.

impl<'a, T: Borrow<R>, R: Display + ?Sized> Display for Cow<'a, T, R>

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

Formats the value using the given formatter.

impl<'a, T: Borrow<R>, R: Eq + ?Sized> Eq for Cow<'a, T, R>

impl<'a, T: Borrow<R>, R: Hash + ?Sized> Hash for Cow<'a, T, R>

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<'a, T: Borrow<R>, R: Ord + ?Sized> Ord for Cow<'a, T, R>

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

This method returns an Ordering between self and other.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

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

Restrict a value to a certain interval.

impl<'a, T: Borrow<R>, R: PartialEq + ?Sized> PartialEq<Cow<'a, T, R>> for Cow<'a, T, R>

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

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

#[must_use]fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<'a, T: Borrow<R>, R: PartialEq + ?Sized> PartialEq<R> for Cow<'a, T, R>

fn eq(&self, other: &R) -> bool

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

#[must_use]fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<'a, T: Borrow<R>, R: PartialOrd + ?Sized> PartialOrd<Cow<'a, T, R>> for Cow<'a, T, R>

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<'a, T: Borrow<R>, R: PartialOrd + ?Sized> PartialOrd<R> for Cow<'a, T, R>

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

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

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

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

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

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

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

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

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

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