Enum collections::borrow::CowStable

pub enum Cow<'a, B: ?Sized + 'a> where B: ToOwned {
    // some variants omitted
}

A clone-on-write smart pointer.

The type Cow is a smart pointer providing clone-on-write functionality: it can enclose and provide immutable access to borrowed data, and clone the data lazily when mutation or ownership is required. The type is designed to work with general borrowed data via the Borrow trait.

Cow implements both Deref, which means that you can call non-mutating methods directly on the data it encloses. If mutation is desired, to_mut will obtain a mutable references to an owned value, cloning if necessary.

Example

fn main() { use std::borrow::Cow; fn abs_all(input: &mut Cow<[int]>) { for i in 0..input.len() { let v = input[i]; if v < 0 { // clones into a vector the first time (if not already owned) input.to_mut()[i] = -v; } } } }

use std::borrow::Cow;

fn abs_all(input: &mut Cow<[int]>) {
    for i in 0..input.len() {
        let v = input[i];
        if v < 0 {
            // clones into a vector the first time (if not already owned)
            input.to_mut()[i] = -v;
        }
    }
}

Methods

impl<'a, B: ?Sized> Cow<'a, B> where B: ToOwned

fn to_mut(&mut self) -> &mut <B as ToOwned>::Owned

Acquire a mutable reference to the owned form of the data.

Copies the data if it is not already owned.

fn into_owned(self) -> <B as ToOwned>::Owned

Extract the owned data.

Copies the data if it is not already owned.

fn is_borrowed(&self) -> bool

Returns true if this Cow wraps a borrowed value

fn is_owned(&self) -> bool

Returns true if this Cow wraps an owned value

Trait Implementations

impl<'a> PartialEq<String> for Cow<'a, str>

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

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

impl<'a, 'b> PartialEq<&'b str> for Cow<'a, str>

fn eq(&self, other: &&'b str) -> bool

fn ne(&self, other: &&'b str) -> bool

impl<'a> Str for Cow<'a, str>

fn as_slice<'b>(&'b self) -> &'b str

impl<'a, A, B> PartialEq<Vec<B>> for Cow<'a, [A]> where A: PartialEq<B> + Clone

fn eq(&self, other: &Vec<B>) -> bool

fn ne(&self, other: &Vec<B>) -> bool

impl<'a, 'b, A, B> PartialEq<&'b [B]> for Cow<'a, [A]> where A: PartialEq<B> + Clone

fn eq(&self, other: &&'b [B]) -> bool

fn ne(&self, other: &&'b [B]) -> bool

impl<'a, 'b, A, B> PartialEq<&'b mut [B]> for Cow<'a, [A]> where A: PartialEq<B> + Clone

fn eq(&self, other: &&'b mut [B]) -> bool

fn ne(&self, other: &&'b mut [B]) -> bool

impl<'a, T> FromIterator<T> for Cow<'a, [T]> where T: Clone

fn from_iter<I: IntoIterator<Item=T>>(it: I) -> Cow<'a, [T]>

impl<'a, B: ?Sized> Borrow<B> for Cow<'a, B> where B: ToOwned, <B as ToOwned>::Owned: 'a

fn borrow(&self) -> &B

impl<'a, B: ?Sized> Clone for Cow<'a, B> where B: ToOwned

fn clone(&self) -> Cow<'a, B>

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

impl<'a, B: ?Sized> Deref for Cow<'a, B> where B: ToOwned

type Target = B

fn deref(&self) -> &B

impl<'a, B: ?Sized> Eq for Cow<'a, B> where B: Eq + ToOwned

fn assert_receiver_is_total_eq(&self)

impl<'a, B: ?Sized> Ord for Cow<'a, B> where B: Ord + ToOwned

fn cmp(&self, other: &Cow<'a, B>) -> Ordering

impl<'a, 'b, B: ?Sized, C: ?Sized> PartialEq<Cow<'b, C>> for Cow<'a, B> where B: PartialEq<C> + ToOwned, C: ToOwned

fn eq(&self, other: &Cow<'b, C>) -> bool

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

impl<'a, B: ?Sized> PartialOrd for Cow<'a, B> where B: PartialOrd + ToOwned

fn partial_cmp(&self, other: &Cow<'a, B>) -> Option<Ordering>

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

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

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

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

impl<'a, B: ?Sized> Debug for Cow<'a, B> where B: Debug + ToOwned, <B as ToOwned>::Owned: Debug

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

impl<'a, B: ?Sized> Display for Cow<'a, B> where B: Display + ToOwned, <B as ToOwned>::Owned: Display

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

impl<'a, B: ?Sized> Hash for Cow<'a, B> where B: Hash + ToOwned

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

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

impl<'a, B: ?Sized> IntoCow<'a, B> for Cow<'a, B> where B: ToOwned

fn into_cow(self) -> Cow<'a, B>