pub enum Cow<'a, B> where
B: 'a + ToOwned + ?Sized, {
Borrowed(&'a B),
Owned(<B as ToOwned>::Owned),
}
Expand description
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 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 reference to an owned
value, cloning if necessary.
If you need reference-counting pointers, note that
Rc::make_mut
and
Arc::make_mut
can provide clone-on-write
functionality as well.
Examples
use std::borrow::Cow;
fn abs_all(input: &mut Cow<[i32]>) {
for i in 0..input.len() {
let v = input[i];
if v < 0 {
// Clones into a vector if not already owned.
input.to_mut()[i] = -v;
}
}
}
// No clone occurs because `input` doesn't need to be mutated.
let slice = [0, 1, 2];
let mut input = Cow::from(&slice[..]);
abs_all(&mut input);
// Clone occurs because `input` needs to be mutated.
let slice = [-1, 0, 1];
let mut input = Cow::from(&slice[..]);
abs_all(&mut input);
// No clone occurs because `input` is already owned.
let mut input = Cow::from(vec![-1, 0, 1]);
abs_all(&mut input);
Another example showing how to keep Cow
in a struct:
use std::borrow::Cow;
struct Items<'a, X: 'a> where [X]: ToOwned<Owned = Vec<X>> {
values: Cow<'a, [X]>,
}
impl<'a, X: Clone + 'a> Items<'a, X> where [X]: ToOwned<Owned = Vec<X>> {
fn new(v: Cow<'a, [X]>) -> Self {
Items { values: v }
}
}
// Creates a container from borrowed values of a slice
let readonly = [1, 2];
let borrowed = Items::new((&readonly[..]).into());
match borrowed {
Items { values: Cow::Borrowed(b) } => println!("borrowed {:?}", b),
_ => panic!("expect borrowed value"),
}
let mut clone_on_write = borrowed;
// Mutates the data from slice into owned vec and pushes a new value on top
clone_on_write.values.to_mut().push(3);
println!("clone_on_write = {:?}", clone_on_write.values);
// The data was mutated. Let's check it out.
match clone_on_write {
Items { values: Cow::Owned(_) } => println!("clone_on_write contains owned data"),
_ => panic!("expect owned data"),
}
Variants
Borrowed(&'a B)
Borrowed data.
Owned(<B as ToOwned>::Owned)
Owned data.
Implementations
🔬 This is a nightly-only experimental API. (cow_is_borrowed
)
cow_is_borrowed
)Returns true if the data is borrowed, i.e. if to_mut
would require additional work.
Examples
#![feature(cow_is_borrowed)]
use std::borrow::Cow;
let cow = Cow::Borrowed("moo");
assert!(cow.is_borrowed());
let bull: Cow<'_, str> = Cow::Owned("...moo?".to_string());
assert!(!bull.is_borrowed());
🔬 This is a nightly-only experimental API. (cow_is_borrowed
)
cow_is_borrowed
)Returns true if the data is owned, i.e. if to_mut
would be a no-op.
Examples
#![feature(cow_is_borrowed)]
use std::borrow::Cow;
let cow: Cow<'_, str> = Cow::Owned("moo".to_string());
assert!(cow.is_owned());
let bull = Cow::Borrowed("...moo?");
assert!(!bull.is_owned());
Acquires a mutable reference to the owned form of the data.
Clones the data if it is not already owned.
Examples
use std::borrow::Cow;
let mut cow = Cow::Borrowed("foo");
cow.to_mut().make_ascii_uppercase();
assert_eq!(
cow,
Cow::Owned(String::from("FOO")) as Cow<str>
);
Extracts the owned data.
Clones the data if it is not already owned.
Examples
Calling into_owned
on a Cow::Borrowed
clones the underlying data
and becomes a Cow::Owned
:
use std::borrow::Cow;
let s = "Hello world!";
let cow = Cow::Borrowed(s);
assert_eq!(
cow.into_owned(),
String::from(s)
);
Calling into_owned
on a Cow::Owned
is a no-op:
use std::borrow::Cow;
let s = "Hello world!";
let cow: Cow<str> = Cow::Owned(String::from(s));
assert_eq!(
cow.into_owned(),
String::from(s)
);
Trait Implementations
Performs the +=
operation. Read more
Performs the +=
operation. Read more
impl<'de, 'a, T> Deserialize<'de> for Cow<'a, T> where
T: ToOwned + ?Sized,
<T as ToOwned>::Owned: Deserialize<'de>,
impl<'de, 'a, T> Deserialize<'de> for Cow<'a, T> where
T: ToOwned + ?Sized,
<T as ToOwned>::Owned: Deserialize<'de>,
pub fn deserialize<D>(
deserializer: D
) -> Result<Cow<'a, T>, <D as Deserializer<'de>>::Error> where
D: Deserializer<'de>,
pub fn deserialize<D>(
deserializer: D
) -> Result<Cow<'a, T>, <D as Deserializer<'de>>::Error> where
D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
Extends a collection with the contents of an iterator. Read more
extend_one
)Extends a collection with exactly one element.
extend_one
)Reserves capacity in a collection for the given number of additional elements. Read more
pub fn from(cow: Cow<'_, [T]>) -> Box<[T], Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(cow: Cow<'_, [T]>) -> Box<[T], Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Converts a Cow<'_, [T]>
into a Box<[T]>
When cow
is the Cow::Borrowed
variant, this
conversion allocates on the heap and copies the
underlying slice. Otherwise, it will try to reuse the owned
Vec
’s allocation.
pub fn from(cow: Cow<'_, CStr>) -> Box<CStr, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(cow: Cow<'_, CStr>) -> Box<CStr, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Performs the conversion.
pub fn from(cow: Cow<'_, OsStr>) -> Box<OsStr, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(cow: Cow<'_, OsStr>) -> Box<OsStr, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Performs the conversion.
pub fn from(cow: Cow<'_, Path>) -> Box<Path, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(cow: Cow<'_, Path>) -> Box<Path, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Creates a boxed Path
from a clone-on-write pointer.
Converting from a Cow::Owned
does not clone or allocate.
pub fn from(cow: Cow<'_, str>) -> Box<str, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(cow: Cow<'_, str>) -> Box<str, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Converts a Cow<'_, str>
into a Box<str>
When cow
is the Cow::Borrowed
variant, this
conversion allocates on the heap and copies the
underlying str
. Otherwise, it will try to reuse the owned
String
’s allocation.
Examples
use std::borrow::Cow;
let unboxed = Cow::Borrowed("hello");
let boxed: Box<str> = Box::from(unboxed);
println!("{}", boxed);
let unboxed = Cow::Owned("hello".to_string());
let boxed: Box<str> = Box::from(unboxed);
println!("{}", boxed);
Convert a clone-on-write slice into a vector.
If s
already owns a Vec<T>
, it will be returned directly.
If s
is borrowing a slice, a new Vec<T>
will be allocated and
filled by cloning s
’s items into it.
Examples
let o: Cow<[i32]> = Cow::Owned(vec![1, 2, 3]);
let b: Cow<[i32]> = Cow::Borrowed(&[1, 2, 3]);
assert_eq!(Vec::from(o), Vec::from(b));
pub fn from(err: Cow<'a, str>) -> Box<dyn Error + 'static, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(err: Cow<'a, str>) -> Box<dyn Error + 'static, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Converts a clone-on-write string to an owned
instance of String
.
This extracts the owned string, clones the string if it is not already owned.
Example
// If the string is not owned...
let cow: Cow<str> = Cow::Borrowed("eggplant");
// It will allocate on the heap and copy the string.
let owned: String = String::from(cow);
assert_eq!(&owned[..], "eggplant");
pub fn from(err: Cow<'b, str>) -> Box<dyn Error + Sync + Send + 'a, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
pub fn from(err: Cow<'b, str>) -> Box<dyn Error + Sync + Send + 'a, Global>ⓘimpl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;
Converts a Cow
into a box of dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error;
use std::mem;
use std::borrow::Cow;
let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
type Deserializer = CowStrDeserializer<'a, E>
type Deserializer = CowStrDeserializer<'a, E>
The type of the deserializer being converted into.
Convert this value into a deserializer.
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
pub fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
S: Serializer,
pub fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
S: Serializer,
Serialize this value into the given Serde serializer. Read more
Auto Trait Implementations
impl<'a, B: ?Sized> RefUnwindSafe for Cow<'a, B> where
B: RefUnwindSafe,
<B as ToOwned>::Owned: RefUnwindSafe,
impl<'a, B: ?Sized> UnwindSafe for Cow<'a, B> where
B: RefUnwindSafe,
<B as ToOwned>::Owned: UnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more
Causes self
to use its Binary
implementation when Debug
-formatted.
Causes self
to use its Display
implementation when
Debug
-formatted. Read more
Causes self
to use its LowerExp
implementation when
Debug
-formatted. Read more
Causes self
to use its LowerHex
implementation when
Debug
-formatted. Read more
Causes self
to use its Octal
implementation when Debug
-formatted.
Causes self
to use its Pointer
implementation when
Debug
-formatted. Read more
Causes self
to use its UpperExp
implementation when
Debug
-formatted. Read more
Causes self
to use its UpperHex
implementation when
Debug
-formatted. Read more
Pipes by value. This is generally the method you want to use. Read more
Borrows self
and passes that borrow into the pipe function. Read more
Mutably borrows self
and passes that borrow into the pipe function. Read more
Borrows self
, then passes self.borrow()
into the pipe function. Read more
Mutably borrows self
, then passes self.borrow_mut()
into the pipe
function. Read more
Borrows self
, then passes self.as_ref()
into the pipe function.
Mutably borrows self
, then passes self.as_mut()
into the pipe
function. Read more
Borrows self
, then passes self.deref()
into the pipe function.
fn pipe_as_ref<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R where
Self: AsRef<T>,
T: 'a,
R: 'a,
fn pipe_as_ref<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R where
Self: AsRef<T>,
T: 'a,
R: 'a,
Pipes a trait borrow into a function that cannot normally be called in suffix position. Read more
fn pipe_borrow<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R where
Self: Borrow<T>,
T: 'a,
R: 'a,
fn pipe_borrow<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R where
Self: Borrow<T>,
T: 'a,
R: 'a,
Pipes a trait borrow into a function that cannot normally be called in suffix position. Read more
fn pipe_deref<'a, R>(&'a self, func: impl FnOnce(&'a Self::Target) -> R) -> R where
Self: Deref,
R: 'a,
fn pipe_deref<'a, R>(&'a self, func: impl FnOnce(&'a Self::Target) -> R) -> R where
Self: Deref,
R: 'a,
Pipes a dereference into a function that cannot normally be called in suffix position. Read more
Pipes a reference into a function that cannot ordinarily be called in suffix position. Read more
Immutable access to the Borrow<B>
of a value. Read more
Mutable access to the BorrowMut<B>
of a value. Read more
Immutable access to the AsRef<R>
view of a value. Read more
Mutable access to the AsMut<R>
view of a value. Read more
Immutable access to the Deref::Target
of a value. Read more
Mutable access to the Deref::Target
of a value. Read more
Calls .tap()
only in debug builds, and is erased in release builds.
Calls .tap_mut()
only in debug builds, and is erased in release
builds. Read more
Calls .tap_borrow()
only in debug builds, and is erased in release
builds. Read more
Calls .tap_borrow_mut()
only in debug builds, and is erased in release
builds. Read more
Calls .tap_ref()
only in debug builds, and is erased in release
builds. Read more
Calls .tap_ref_mut()
only in debug builds, and is erased in release
builds. Read more
Calls .tap_deref()
only in debug builds, and is erased in release
builds. Read more
Provides immutable access to the reference for inspection.
Calls tap_ref
in debug builds, and does nothing in release builds.
Provides mutable access to the reference for modification.
Calls tap_ref_mut
in debug builds, and does nothing in release builds.
Provides immutable access to the borrow for inspection. Read more
Calls tap_borrow
in debug builds, and does nothing in release builds.
fn tap_borrow_mut<F, R>(self, func: F) -> Self where
Self: BorrowMut<T>,
F: FnOnce(&mut T) -> R,
fn tap_borrow_mut<F, R>(self, func: F) -> Self where
Self: BorrowMut<T>,
F: FnOnce(&mut T) -> R,
Provides mutable access to the borrow for modification.
Immutably dereferences self
for inspection.
fn tap_deref_dbg<F, R>(self, func: F) -> Self where
Self: Deref,
F: FnOnce(&Self::Target) -> R,
fn tap_deref_dbg<F, R>(self, func: F) -> Self where
Self: Deref,
F: FnOnce(&Self::Target) -> R,
Calls tap_deref
in debug builds, and does nothing in release builds.
fn tap_deref_mut<F, R>(self, func: F) -> Self where
Self: DerefMut,
F: FnOnce(&mut Self::Target) -> R,
fn tap_deref_mut<F, R>(self, func: F) -> Self where
Self: DerefMut,
F: FnOnce(&mut Self::Target) -> R,
Mutably dereferences self
for modification.