Enum Option

pub enum Option<T> {
    None,
    Some(T),
}

Available on crate feature mtls only.

The Option type. See the module level documentation for more.

Variants

None

No value.

Some(T)

Some value of type T.

Implementations

impl<T> Option<T>

pub const fn is_some(&self) -> bool

Returns true if the option is a Some value.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_some(), true);

let x: Option<u32> = None;
assert_eq!(x.is_some(), false);

pub fn is_some_and(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the option is a Some and the value inside of it matches a predicate.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_some_and(|x| x > 1), true);

let x: Option<u32> = Some(0);
assert_eq!(x.is_some_and(|x| x > 1), false);

let x: Option<u32> = None;
assert_eq!(x.is_some_and(|x| x > 1), false);

pub const fn is_none(&self) -> bool

Returns true if the option is a None value.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_none(), false);

let x: Option<u32> = None;
assert_eq!(x.is_none(), true);

pub fn is_none_or(self, f: impl FnOnce(T) -> bool) -> bool

Returns true if the option is a None or the value inside of it matches a predicate.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_none_or(|x| x > 1), true);

let x: Option<u32> = Some(0);
assert_eq!(x.is_none_or(|x| x > 1), false);

let x: Option<u32> = None;
assert_eq!(x.is_none_or(|x| x > 1), true);

pub const fn as_ref(&self) -> Option<&T>

Converts from &Option<T> to Option<&T>.

Examples

Calculates the length of an Option<String> as an Option<usize> without moving the String. The map method takes the self argument by value, consuming the original, so this technique uses as_ref to first take an Option to a reference to the value inside the original.

let text: Option<String> = Some("Hello, world!".to_string());
// First, cast `Option<String>` to `Option<&String>` with `as_ref`,
// then consume *that* with `map`, leaving `text` on the stack.
let text_length: Option<usize> = text.as_ref().map(|s| s.len());
println!("still can print text: {text:?}");

pub const fn as_mut(&mut self) -> Option<&mut T>

Converts from &mut Option<T> to Option<&mut T>.

Examples

let mut x = Some(2);
match x.as_mut() {
    Some(v) => *v = 42,
    None => {},
}
assert_eq!(x, Some(42));

pub const fn as_pin_ref(self: Pin<&Option<T>>) -> Option<Pin<&T>>

Converts from Pin<&Option<T>> to Option<Pin<&T>>.

pub const fn as_pin_mut(self: Pin<&mut Option<T>>) -> Option<Pin<&mut T>>

Converts from Pin<&mut Option<T>> to Option<Pin<&mut T>>.

pub const fn as_slice(&self) -> &[T]

Returns a slice of the contained value, if any. If this is None, an empty slice is returned. This can be useful to have a single type of iterator over an Option or slice.

Note: Should you have an Option<&T> and wish to get a slice of T, you can unpack it via opt.map_or(&[], std::slice::from_ref).

Examples

assert_eq!(
    [Some(1234).as_slice(), None.as_slice()],
    [&[1234][..], &[][..]],
);

The inverse of this function is (discounting borrowing) [_]::first:

for i in [Some(1234_u16), None] {
    assert_eq!(i.as_ref(), i.as_slice().first());
}

pub const fn as_mut_slice(&mut self) -> &mut [T]

Returns a mutable slice of the contained value, if any. If this is None, an empty slice is returned. This can be useful to have a single type of iterator over an Option or slice.

Note: Should you have an Option<&mut T> instead of a &mut Option<T>, which this method takes, you can obtain a mutable slice via opt.map_or(&mut [], std::slice::from_mut).

Examples

assert_eq!(
    [Some(1234).as_mut_slice(), None.as_mut_slice()],
    [&mut [1234][..], &mut [][..]],
);

The result is a mutable slice of zero or one items that points into our original Option:

let mut x = Some(1234);
x.as_mut_slice()[0] += 1;
assert_eq!(x, Some(1235));

The inverse of this method (discounting borrowing) is [_]::first_mut:

assert_eq!(Some(123).as_mut_slice().first_mut(), Some(&mut 123))

pub const fn expect(self, msg: &str) -> T

Returns the contained Some value, consuming the self value.

Panics

Panics if the value is a None with a custom panic message provided by msg.

Examples

let x = Some("value");
assert_eq!(x.expect("fruits are healthy"), "value");

let x: Option<&str> = None;
x.expect("fruits are healthy"); // panics with `fruits are healthy`

Recommended Message Style

We recommend that expect messages are used to describe the reason you expect the Option should be Some.

let item = slice.get(0)
    .expect("slice should not be empty");

Hint: If you’re having trouble remembering how to phrase expect error messages remember to focus on the word “should” as in “env variable should be set by blah” or “the given binary should be available and executable by the current user”.

For more detail on expect message styles and the reasoning behind our recommendation please refer to the section on “Common Message Styles” in the std::error module docs.

pub const fn unwrap(self) -> T

Returns the contained Some value, consuming the self value.

Because this function may panic, its use is generally discouraged. Instead, prefer to use pattern matching and handle the None case explicitly, or call unwrap_or, unwrap_or_else, or unwrap_or_default.

Panics

Panics if the self value equals None.

Examples

let x = Some("air");
assert_eq!(x.unwrap(), "air");

let x: Option<&str> = None;
assert_eq!(x.unwrap(), "air"); // fails

pub fn unwrap_or(self, default: T) -> T

Returns the contained Some value or a provided default.

Arguments passed to unwrap_or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use unwrap_or_else, which is lazily evaluated.

Examples

assert_eq!(Some("car").unwrap_or("bike"), "car");
assert_eq!(None.unwrap_or("bike"), "bike");

pub fn unwrap_or_else<F>(self, f: F) -> T

where F: FnOnce() -> T,

Returns the contained Some value or computes it from a closure.

Examples

let k = 10;
assert_eq!(Some(4).unwrap_or_else(|| 2 * k), 4);
assert_eq!(None.unwrap_or_else(|| 2 * k), 20);

pub fn unwrap_or_default(self) -> T

where T: Default,

Returns the contained Some value or a default.

Consumes the self argument then, if Some, returns the contained value, otherwise if None, returns the default value for that type.

Examples

let x: Option<u32> = None;
let y: Option<u32> = Some(12);

assert_eq!(x.unwrap_or_default(), 0);
assert_eq!(y.unwrap_or_default(), 12);

pub const unsafe fn unwrap_unchecked(self) -> T

Returns the contained Some value, consuming the self value, without checking that the value is not None.

Safety

Calling this method on None is undefined behavior.

Examples

let x = Some("air");
assert_eq!(unsafe { x.unwrap_unchecked() }, "air");

let x: Option<&str> = None;
assert_eq!(unsafe { x.unwrap_unchecked() }, "air"); // Undefined behavior!

pub fn map<U, F>(self, f: F) -> Option<U>

where F: FnOnce(T) -> U,

Maps an Option<T> to Option<U> by applying a function to a contained value (if Some) or returns None (if None).

Examples

Calculates the length of an Option<String> as an Option<usize>, consuming the original:

let maybe_some_string = Some(String::from("Hello, World!"));
// `Option::map` takes self *by value*, consuming `maybe_some_string`
let maybe_some_len = maybe_some_string.map(|s| s.len());
assert_eq!(maybe_some_len, Some(13));

let x: Option<&str> = None;
assert_eq!(x.map(|s| s.len()), None);

pub fn inspect<F>(self, f: F) -> Option<T>

where F: FnOnce(&T),

Calls a function with a reference to the contained value if Some.

Returns the original option.

Examples

let list = vec![1, 2, 3];

// prints "got: 2"
let x = list
    .get(1)
    .inspect(|x| println!("got: {x}"))
    .expect("list should be long enough");

// prints nothing
list.get(5).inspect(|x| println!("got: {x}"));

pub fn map_or<U, F>(self, default: U, f: F) -> U

where F: FnOnce(T) -> U,

Returns the provided default result (if none), or applies a function to the contained value (if any).

Arguments passed to map_or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use map_or_else, which is lazily evaluated.

Examples

let x = Some("foo");
assert_eq!(x.map_or(42, |v| v.len()), 3);

let x: Option<&str> = None;
assert_eq!(x.map_or(42, |v| v.len()), 42);

pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U

where D: FnOnce() -> U, F: FnOnce(T) -> U,

Computes a default function result (if none), or applies a different function to the contained value (if any).

Basic examples

let k = 21;

let x = Some("foo");
assert_eq!(x.map_or_else(|| 2 * k, |v| v.len()), 3);

let x: Option<&str> = None;
assert_eq!(x.map_or_else(|| 2 * k, |v| v.len()), 42);

Handling a Result-based fallback

A somewhat common occurrence when dealing with optional values in combination with Result<T, E> is the case where one wants to invoke a fallible fallback if the option is not present. This example parses a command line argument (if present), or the contents of a file to an integer. However, unlike accessing the command line argument, reading the file is fallible, so it must be wrapped with Ok.

let v: u64 = std::env::args()
   .nth(1)
   .map_or_else(|| std::fs::read_to_string("/etc/someconfig.conf"), Ok)?
   .parse()?;

pub fn ok_or<E>(self, err: E) -> Result<T, E>

Transforms the Option<T> into a Result<T, E>, mapping Some(v) to Ok(v) and None to Err(err).

Arguments passed to ok_or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use ok_or_else, which is lazily evaluated.

Examples

let x = Some("foo");
assert_eq!(x.ok_or(0), Ok("foo"));

let x: Option<&str> = None;
assert_eq!(x.ok_or(0), Err(0));

pub fn ok_or_else<E, F>(self, err: F) -> Result<T, E>

where F: FnOnce() -> E,

Transforms the Option<T> into a Result<T, E>, mapping Some(v) to Ok(v) and None to Err(err()).

Examples

let x = Some("foo");
assert_eq!(x.ok_or_else(|| 0), Ok("foo"));

let x: Option<&str> = None;
assert_eq!(x.ok_or_else(|| 0), Err(0));

pub fn as_deref(&self) -> Option<&<T as Deref>::Target>

where T: Deref,

Converts from Option<T> (or &Option<T>) to Option<&T::Target>.

Leaves the original Option in-place, creating a new one with a reference to the original one, additionally coercing the contents via Deref.

Examples

let x: Option<String> = Some("hey".to_owned());
assert_eq!(x.as_deref(), Some("hey"));

let x: Option<String> = None;
assert_eq!(x.as_deref(), None);

pub fn as_deref_mut(&mut self) -> Option<&mut <T as Deref>::Target>

where T: DerefMut,

Converts from Option<T> (or &mut Option<T>) to Option<&mut T::Target>.

Leaves the original Option in-place, creating a new one containing a mutable reference to the inner type’s Deref::Target type.

Examples

let mut x: Option<String> = Some("hey".to_owned());
assert_eq!(x.as_deref_mut().map(|x| {
    x.make_ascii_uppercase();
    x
}), Some("HEY".to_owned().as_mut_str()));

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

Examples

let x = Some(4);
assert_eq!(x.iter().next(), Some(&4));

let x: Option<u32> = None;
assert_eq!(x.iter().next(), None);

pub fn iter_mut(&mut self) -> IterMut<'_, T>

Returns a mutable iterator over the possibly contained value.

Examples

let mut x = Some(4);
match x.iter_mut().next() {
    Some(v) => *v = 42,
    None => {},
}
assert_eq!(x, Some(42));

let mut x: Option<u32> = None;
assert_eq!(x.iter_mut().next(), None);

pub fn and<U>(self, optb: Option<U>) -> Option<U>

Returns None if the option is None, otherwise returns optb.

Arguments passed to and are eagerly evaluated; if you are passing the result of a function call, it is recommended to use and_then, which is lazily evaluated.

Examples

let x = Some(2);
let y: Option<&str> = None;
assert_eq!(x.and(y), None);

let x: Option<u32> = None;
let y = Some("foo");
assert_eq!(x.and(y), None);

let x = Some(2);
let y = Some("foo");
assert_eq!(x.and(y), Some("foo"));

let x: Option<u32> = None;
let y: Option<&str> = None;
assert_eq!(x.and(y), None);

pub fn and_then<U, F>(self, f: F) -> Option<U>

where F: FnOnce(T) -> Option<U>,

Returns None if the option is None, otherwise calls f with the wrapped value and returns the result.

Some languages call this operation flatmap.

Examples

fn sq_then_to_string(x: u32) -> Option<String> {
    x.checked_mul(x).map(|sq| sq.to_string())
}

assert_eq!(Some(2).and_then(sq_then_to_string), Some(4.to_string()));
assert_eq!(Some(1_000_000).and_then(sq_then_to_string), None); // overflowed!
assert_eq!(None.and_then(sq_then_to_string), None);

Often used to chain fallible operations that may return None.

let arr_2d = [["A0", "A1"], ["B0", "B1"]];

let item_0_1 = arr_2d.get(0).and_then(|row| row.get(1));
assert_eq!(item_0_1, Some(&"A1"));

let item_2_0 = arr_2d.get(2).and_then(|row| row.get(0));
assert_eq!(item_2_0, None);

pub fn filter<P>(self, predicate: P) -> Option<T>

where P: FnOnce(&T) -> bool,

Returns None if the option is None, otherwise calls predicate with the wrapped value and returns:

• Some(t) if predicate returns true (where t is the wrapped value), and
• None if predicate returns false.

This function works similar to Iterator::filter(). You can imagine the Option<T> being an iterator over one or zero elements. filter() lets you decide which elements to keep.

Examples

fn is_even(n: &i32) -> bool {
    n % 2 == 0
}

assert_eq!(None.filter(is_even), None);
assert_eq!(Some(3).filter(is_even), None);
assert_eq!(Some(4).filter(is_even), Some(4));

pub fn or(self, optb: Option<T>) -> Option<T>

Returns the option if it contains a value, otherwise returns optb.

Arguments passed to or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use or_else, which is lazily evaluated.

Examples

let x = Some(2);
let y = None;
assert_eq!(x.or(y), Some(2));

let x = None;
let y = Some(100);
assert_eq!(x.or(y), Some(100));

let x = Some(2);
let y = Some(100);
assert_eq!(x.or(y), Some(2));

let x: Option<u32> = None;
let y = None;
assert_eq!(x.or(y), None);

pub fn or_else<F>(self, f: F) -> Option<T>

where F: FnOnce() -> Option<T>,

Returns the option if it contains a value, otherwise calls f and returns the result.

Examples

fn nobody() -> Option<&'static str> { None }
fn vikings() -> Option<&'static str> { Some("vikings") }

assert_eq!(Some("barbarians").or_else(vikings), Some("barbarians"));
assert_eq!(None.or_else(vikings), Some("vikings"));
assert_eq!(None.or_else(nobody), None);

pub fn xor(self, optb: Option<T>) -> Option<T>

Returns Some if exactly one of self, optb is Some, otherwise returns None.

Examples

let x = Some(2);
let y: Option<u32> = None;
assert_eq!(x.xor(y), Some(2));

let x: Option<u32> = None;
let y = Some(2);
assert_eq!(x.xor(y), Some(2));

let x = Some(2);
let y = Some(2);
assert_eq!(x.xor(y), None);

let x: Option<u32> = None;
let y: Option<u32> = None;
assert_eq!(x.xor(y), None);

pub fn insert(&mut self, value: T) -> &mut T

Inserts value into the option, then returns a mutable reference to it.

If the option already contains a value, the old value is dropped.

See also Option::get_or_insert, which doesn’t update the value if the option already contains Some.

Example

let mut opt = None;
let val = opt.insert(1);
assert_eq!(*val, 1);
assert_eq!(opt.unwrap(), 1);
let val = opt.insert(2);
assert_eq!(*val, 2);
*val = 3;
assert_eq!(opt.unwrap(), 3);

pub fn get_or_insert(&mut self, value: T) -> &mut T

Inserts value into the option if it is None, then returns a mutable reference to the contained value.

See also Option::insert, which updates the value even if the option already contains Some.

Examples

let mut x = None;

{
    let y: &mut u32 = x.get_or_insert(5);
    assert_eq!(y, &5);

    *y = 7;
}

assert_eq!(x, Some(7));

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

where T: Default,

Inserts the default value into the option if it is None, then returns a mutable reference to the contained value.

Examples

let mut x = None;

{
    let y: &mut u32 = x.get_or_insert_default();
    assert_eq!(y, &0);

    *y = 7;
}

assert_eq!(x, Some(7));

pub fn get_or_insert_with<F>(&mut self, f: F) -> &mut T

where F: FnOnce() -> T,

Inserts a value computed from f into the option if it is None, then returns a mutable reference to the contained value.

Examples

let mut x = None;

{
    let y: &mut u32 = x.get_or_insert_with(|| 5);
    assert_eq!(y, &5);

    *y = 7;
}

assert_eq!(x, Some(7));

pub const fn take(&mut self) -> Option<T>

Takes the value out of the option, leaving a None in its place.

Examples

let mut x = Some(2);
let y = x.take();
assert_eq!(x, None);
assert_eq!(y, Some(2));

let mut x: Option<u32> = None;
let y = x.take();
assert_eq!(x, None);
assert_eq!(y, None);

pub fn take_if<P>(&mut self, predicate: P) -> Option<T>

where P: FnOnce(&mut T) -> bool,

Takes the value out of the option, but only if the predicate evaluates to true on a mutable reference to the value.

In other words, replaces self with None if the predicate returns true. This method operates similar to Option::take but conditional.

Examples

let mut x = Some(42);

let prev = x.take_if(|v| if *v == 42 {
    *v += 1;
    false
} else {
    false
});
assert_eq!(x, Some(43));
assert_eq!(prev, None);

let prev = x.take_if(|v| *v == 43);
assert_eq!(x, None);
assert_eq!(prev, Some(43));

pub const fn replace(&mut self, value: T) -> Option<T>

Replaces the actual value in the option by the value given in parameter, returning the old value if present, leaving a Some in its place without deinitializing either one.

Examples

let mut x = Some(2);
let old = x.replace(5);
assert_eq!(x, Some(5));
assert_eq!(old, Some(2));

let mut x = None;
let old = x.replace(3);
assert_eq!(x, Some(3));
assert_eq!(old, None);

pub fn zip<U>(self, other: Option<U>) -> Option<(T, U)>

Zips self with another Option.

If self is Some(s) and other is Some(o), this method returns Some((s, o)). Otherwise, None is returned.

Examples

let x = Some(1);
let y = Some("hi");
let z = None::<u8>;

assert_eq!(x.zip(y), Some((1, "hi")));
assert_eq!(x.zip(z), None);

pub fn zip_with<U, F, R>(self, other: Option<U>, f: F) -> Option<R>

where F: FnOnce(T, U) -> R,

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

Zips self and another Option with function f.

If self is Some(s) and other is Some(o), this method returns Some(f(s, o)). Otherwise, None is returned.

Examples

#![feature(option_zip)]

#[derive(Debug, PartialEq)]
struct Point {
    x: f64,
    y: f64,
}

impl Point {
    fn new(x: f64, y: f64) -> Self {
        Self { x, y }
    }
}

let x = Some(17.5);
let y = Some(42.7);

assert_eq!(x.zip_with(y, Point::new), Some(Point { x: 17.5, y: 42.7 }));
assert_eq!(x.zip_with(None, Point::new), None);

impl<T, U> Option<(T, U)>

pub fn unzip(self) -> (Option<T>, Option<U>)

Unzips an option containing a tuple of two options.

If self is Some((a, b)) this method returns (Some(a), Some(b)). Otherwise, (None, None) is returned.

Examples

let x = Some((1, "hi"));
let y = None::<(u8, u32)>;

assert_eq!(x.unzip(), (Some(1), Some("hi")));
assert_eq!(y.unzip(), (None, None));

impl<T> Option<&T>

pub const fn copied(self) -> Option<T>

where T: Copy,

Maps an Option<&T> to an Option<T> by copying the contents of the option.

Examples

let x = 12;
let opt_x = Some(&x);
assert_eq!(opt_x, Some(&12));
let copied = opt_x.copied();
assert_eq!(copied, Some(12));

pub fn cloned(self) -> Option<T>

where T: Clone,

Maps an Option<&T> to an Option<T> by cloning the contents of the option.

Examples

let x = 12;
let opt_x = Some(&x);
assert_eq!(opt_x, Some(&12));
let cloned = opt_x.cloned();
assert_eq!(cloned, Some(12));

impl<T> Option<&mut T>

pub const fn copied(self) -> Option<T>

where T: Copy,

Maps an Option<&mut T> to an Option<T> by copying the contents of the option.

Examples

let mut x = 12;
let opt_x = Some(&mut x);
assert_eq!(opt_x, Some(&mut 12));
let copied = opt_x.copied();
assert_eq!(copied, Some(12));

pub fn cloned(self) -> Option<T>

where T: Clone,

Maps an Option<&mut T> to an Option<T> by cloning the contents of the option.

Examples

let mut x = 12;
let opt_x = Some(&mut x);
assert_eq!(opt_x, Some(&mut 12));
let cloned = opt_x.cloned();
assert_eq!(cloned, Some(12));

impl<T, E> Option<Result<T, E>>

pub const fn transpose(self) -> Result<Option<T>, E>

Transposes an Option of a Result into a Result of an Option.

None will be mapped to Ok(None). Some(Ok(_)) and Some(Err(_)) will be mapped to Ok(Some(_)) and Err(_).

Examples

#[derive(Debug, Eq, PartialEq)]
struct SomeErr;

let x: Result<Option<i32>, SomeErr> = Ok(Some(5));
let y: Option<Result<i32, SomeErr>> = Some(Ok(5));
assert_eq!(x, y.transpose());

impl<T> Option<Option<T>>

pub const fn flatten(self) -> Option<T>

Converts from Option<Option<T>> to Option<T>.

Examples

Basic usage:

let x: Option<Option<u32>> = Some(Some(6));
assert_eq!(Some(6), x.flatten());

let x: Option<Option<u32>> = Some(None);
assert_eq!(None, x.flatten());

let x: Option<Option<u32>> = None;
assert_eq!(None, x.flatten());

Flattening only removes one level of nesting at a time:

let x: Option<Option<Option<u32>>> = Some(Some(Some(6)));
assert_eq!(Some(Some(6)), x.flatten());
assert_eq!(Some(6), x.flatten().flatten());

Trait Implementations

impl AsBytes for Option<NonZero<i128>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<i16>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<i32>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<i64>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<i8>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<isize>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<u128>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<u16>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<u32>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<u64>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<u8>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl AsBytes for Option<NonZero<usize>>

fn as_bytes(&self) -> &[u8]

Gets the bytes of this value.

fn as_bytes_mut(&mut self) -> &mut [u8]

where Self: FromBytes,

Gets the bytes of this value mutably.

fn write_to(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to bytes.

fn write_to_prefix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the prefix of bytes.

fn write_to_suffix(&self, bytes: &mut [u8]) -> Option<()>

Writes a copy of self to the suffix of bytes.

impl<A> BoolRecorder for Option<A>

where A: BoolRecorder,

fn record(&self, info: &'static Info, value: bool)

impl<T> CheckDerConstraints for Option<T>

where T: CheckDerConstraints,

fn check_constraints(any: &Any<'_>) -> Result<(), Error>

impl<T> Clear for Option<T>

fn clear(&mut self)

Clear all data in self, retaining the allocated capacithy.

impl<T> Clone for Option<T>

where T: Clone,

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

Returns a copy of the value.

fn clone_from(&mut self, source: &Option<T>)

Performs copy-assignment from source.

impl<I, T: Contains<I>> Contains<I> for Option<T>

fn contains(&self, item: I) -> bool

Returns true if self contains item.

impl<T> Debug for Option<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<'a, T> DecoderValue<'a> for Option<T>

where T: DecoderValue<'a>,

fn decode( buffer: DecoderBuffer<'a>, ) -> Result<(Option<T>, DecoderBuffer<'a>), DecoderError>

impl<'a, T> DecoderValueMut<'a> for Option<T>

where T: DecoderValueMut<'a>,

fn decode_mut( buffer: DecoderBufferMut<'a>, ) -> Result<(Option<T>, DecoderBufferMut<'a>), DecoderError>

impl<T> Default for Option<T>

fn default() -> Option<T>

Returns None.

Examples

let opt: Option<u32> = Option::default();
assert!(opt.is_none());

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

where T: Deserialize<'de>,

fn deserialize<D>( deserializer: D, ) -> Result<Option<T>, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> DynTagged for Option<T>

where T: DynTagged,

fn tag(&self) -> Tag

impl<T> EncoderValue for Option<T>

where T: EncoderValue,

fn encode<E>(&self, buffer: &mut E)

where E: Encoder,

Encodes the value into the encoder

fn encode_mut<E>(&mut self, buffer: &mut E)

where E: Encoder,

Encodes the value into the encoder, while potentially mutating the value itself

fn encoding_size(&self) -> usize

Returns the encoding size with no buffer constrains

fn encoding_size_for_encoder<E>(&self, encoder: &E) -> usize

where E: Encoder,

Returns the encoding size for the given encoder’s capacity

fn encode_with_len_prefix<Len, E>(&self, encoder: &mut E)

where Len: TryFrom<usize> + EncoderValue, E: Encoder, Self: Sized, <Len as TryFrom<usize>>::Error: Debug,

Encodes the value into the encoder with a prefix of Len

fn encode_to_vec(&self) -> Vec<u8>

impl<F, S> Filter<S> for Option<F>

where F: Filter<S>,

fn enabled(&self, meta: &Metadata<'_>, ctx: &Context<'_, S>) -> bool

Returns true if this layer is interested in a span or event with the given Metadata in the current Context, similarly to Subscriber::enabled.

fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest

Returns an Interest indicating whether this layer will always, sometimes, or never be interested in the given Metadata.

fn max_level_hint(&self) -> Option<LevelFilter>

Returns an optional hint of the highest verbosity level that this Filter will enable.

fn event_enabled(&self, event: &Event<'_>, ctx: &Context<'_, S>) -> bool

Called before the filtered [Layer]'s [on_event], to determine if on_event` should be called.

fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)

Notifies this filter that a new span was constructed with the given Attributes and Id.

fn on_record(&self, id: &Id, values: &Record<'_>, ctx: Context<'_, S>)

Notifies this filter that a span with the given Id recorded the given values.

fn on_enter(&self, id: &Id, ctx: Context<'_, S>)

Notifies this filter that a span with the given ID was entered.

fn on_exit(&self, id: &Id, ctx: Context<'_, S>)

Notifies this filter that a span with the given ID was exited.

fn on_close(&self, id: Id, ctx: Context<'_, S>)

Notifies this filter that a span with the given ID has been closed.

impl<'a> From<&'a Current> for Option<&'a Id>

fn from(cur: &'a Current) -> Option<&'a Id>

Converts to this type from the input type.

impl<'a> From<&'a Current> for Option<&'static Metadata<'static>>

fn from(cur: &'a Current) -> Option<&'static Metadata<'static>>

Converts to this type from the input type.

impl<'a> From<&'a Current> for Option<Id>

fn from(cur: &'a Current) -> Option<Id>

Converts to this type from the input type.

impl<'a> From<&'a EnteredSpan> for Option<&'a Id>

fn from(span: &'a EnteredSpan) -> Option<&'a Id>

Converts to this type from the input type.

impl<'a> From<&'a EnteredSpan> for Option<Id>

fn from(span: &'a EnteredSpan) -> Option<Id>

Converts to this type from the input type.

impl<'a> From<&'a Id> for Option<Id>

fn from(id: &'a Id) -> Option<Id>

Converts to this type from the input type.

impl<'a, T> From<&'a Option<T>> for Option<&'a T>

fn from(o: &'a Option<T>) -> Option<&'a T>

Converts from &Option<T> to Option<&T>.

Examples

Converts an Option<String> into an Option<usize>, preserving the original. The map method takes the self argument by value, consuming the original, so this technique uses from to first take an Option to a reference to the value inside the original.

let s: Option<String> = Some(String::from("Hello, Rustaceans!"));
let o: Option<usize> = Option::from(&s).map(|ss: &String| ss.len());

println!("Can still print s: {s:?}");

assert_eq!(o, Some(18));

impl<'a> From<&'a Span> for Option<&'a Id>

fn from(span: &'a Span) -> Option<&'a Id>

Converts to this type from the input type.

impl<'a> From<&'a Span> for Option<Id>

fn from(span: &'a Span) -> Option<Id>

Converts to this type from the input type.

impl<'a, T> From<&'a mut Option<T>> for Option<&'a mut T>

fn from(o: &'a mut Option<T>) -> Option<&'a mut T>

Converts from &mut Option<T> to Option<&mut T>

Examples

let mut s = Some(String::from("Hello"));
let o: Option<&mut String> = Option::from(&mut s);

match o {
    Some(t) => *t = String::from("Hello, Rustaceans!"),
    None => (),
}

assert_eq!(s, Some(String::from("Hello, Rustaceans!")));

impl<T> From<CtOption<T>> for Option<T>

fn from(source: CtOption<T>) -> Option<T>

Convert the CtOption<T> wrapper into an Option<T>, depending on whether the underlying is_some Choice was a 0 or a 1 once unwrapped.

Note

This function exists to avoid ending up with ugly, verbose and/or bad handled conversions from the CtOption<T> wraps to an Option<T> or Result<T, E>. This implementation doesn’t intend to be constant-time nor try to protect the leakage of the T since the Option<T> will do it anyways.

impl From<Current> for Option<Id>

fn from(cur: Current) -> Option<Id>

Converts to this type from the input type.

impl From<LevelFilter> for Option<Level>

fn from(filter: LevelFilter) -> Option<Level>

Converts to this type from the input type.

impl From<Option<Level>> for LevelFilter

fn from(level: Option<Level>) -> LevelFilter

Converts to this type from the input type.

impl<const MIN: i128, const MAX: i128> From<Option<RangedI128<MIN, MAX>>> for OptionRangedI128<MIN, MAX>

fn from(value: Option<RangedI128<MIN, MAX>>) -> OptionRangedI128<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: i16, const MAX: i16> From<Option<RangedI16<MIN, MAX>>> for OptionRangedI16<MIN, MAX>

fn from(value: Option<RangedI16<MIN, MAX>>) -> OptionRangedI16<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: i32, const MAX: i32> From<Option<RangedI32<MIN, MAX>>> for OptionRangedI32<MIN, MAX>

fn from(value: Option<RangedI32<MIN, MAX>>) -> OptionRangedI32<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: i64, const MAX: i64> From<Option<RangedI64<MIN, MAX>>> for OptionRangedI64<MIN, MAX>

fn from(value: Option<RangedI64<MIN, MAX>>) -> OptionRangedI64<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: i8, const MAX: i8> From<Option<RangedI8<MIN, MAX>>> for OptionRangedI8<MIN, MAX>

fn from(value: Option<RangedI8<MIN, MAX>>) -> OptionRangedI8<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: isize, const MAX: isize> From<Option<RangedIsize<MIN, MAX>>> for OptionRangedIsize<MIN, MAX>

fn from(value: Option<RangedIsize<MIN, MAX>>) -> OptionRangedIsize<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: u128, const MAX: u128> From<Option<RangedU128<MIN, MAX>>> for OptionRangedU128<MIN, MAX>

fn from(value: Option<RangedU128<MIN, MAX>>) -> OptionRangedU128<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: u16, const MAX: u16> From<Option<RangedU16<MIN, MAX>>> for OptionRangedU16<MIN, MAX>

fn from(value: Option<RangedU16<MIN, MAX>>) -> OptionRangedU16<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: u32, const MAX: u32> From<Option<RangedU32<MIN, MAX>>> for OptionRangedU32<MIN, MAX>

fn from(value: Option<RangedU32<MIN, MAX>>) -> OptionRangedU32<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: u64, const MAX: u64> From<Option<RangedU64<MIN, MAX>>> for OptionRangedU64<MIN, MAX>

fn from(value: Option<RangedU64<MIN, MAX>>) -> OptionRangedU64<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: u8, const MAX: u8> From<Option<RangedU8<MIN, MAX>>> for OptionRangedU8<MIN, MAX>

fn from(value: Option<RangedU8<MIN, MAX>>) -> OptionRangedU8<MIN, MAX>

Converts to this type from the input type.

impl<const MIN: usize, const MAX: usize> From<Option<RangedUsize<MIN, MAX>>> for OptionRangedUsize<MIN, MAX>

fn from(value: Option<RangedUsize<MIN, MAX>>) -> OptionRangedUsize<MIN, MAX>

Converts to this type from the input type.

impl<T> From<Option<T>> for EitherWriter<T, Sink>

fn from(opt: Option<T>) -> EitherWriter<T, Sink>

Converts to this type from the input type.

impl<T> From<Option<T>> for OptionFuture<T>

fn from(option: Option<T>) -> OptionFuture<T>

Converts to this type from the input type.

impl<T> From<Option<T>> for Value

where T: Into<Value>,

fn from(opt: Option<T>) -> Value

Converts to this type from the input type.

impl From<Option<Timestamp>> for Timer

fn from(expiration: Option<Timestamp>) -> Timer

Converts to this type from the input type.

impl<const MIN: i128, const MAX: i128> From<OptionRangedI128<MIN, MAX>> for Option<RangedI128<MIN, MAX>>

fn from(value: OptionRangedI128<MIN, MAX>) -> Option<RangedI128<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: i16, const MAX: i16> From<OptionRangedI16<MIN, MAX>> for Option<RangedI16<MIN, MAX>>

fn from(value: OptionRangedI16<MIN, MAX>) -> Option<RangedI16<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: i32, const MAX: i32> From<OptionRangedI32<MIN, MAX>> for Option<RangedI32<MIN, MAX>>

fn from(value: OptionRangedI32<MIN, MAX>) -> Option<RangedI32<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: i64, const MAX: i64> From<OptionRangedI64<MIN, MAX>> for Option<RangedI64<MIN, MAX>>

fn from(value: OptionRangedI64<MIN, MAX>) -> Option<RangedI64<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: i8, const MAX: i8> From<OptionRangedI8<MIN, MAX>> for Option<RangedI8<MIN, MAX>>

fn from(value: OptionRangedI8<MIN, MAX>) -> Option<RangedI8<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: isize, const MAX: isize> From<OptionRangedIsize<MIN, MAX>> for Option<RangedIsize<MIN, MAX>>

fn from(value: OptionRangedIsize<MIN, MAX>) -> Option<RangedIsize<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: u128, const MAX: u128> From<OptionRangedU128<MIN, MAX>> for Option<RangedU128<MIN, MAX>>

fn from(value: OptionRangedU128<MIN, MAX>) -> Option<RangedU128<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: u16, const MAX: u16> From<OptionRangedU16<MIN, MAX>> for Option<RangedU16<MIN, MAX>>

fn from(value: OptionRangedU16<MIN, MAX>) -> Option<RangedU16<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: u32, const MAX: u32> From<OptionRangedU32<MIN, MAX>> for Option<RangedU32<MIN, MAX>>

fn from(value: OptionRangedU32<MIN, MAX>) -> Option<RangedU32<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: u64, const MAX: u64> From<OptionRangedU64<MIN, MAX>> for Option<RangedU64<MIN, MAX>>

fn from(value: OptionRangedU64<MIN, MAX>) -> Option<RangedU64<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: u8, const MAX: u8> From<OptionRangedU8<MIN, MAX>> for Option<RangedU8<MIN, MAX>>

fn from(value: OptionRangedU8<MIN, MAX>) -> Option<RangedU8<MIN, MAX>>

Converts to this type from the input type.

impl<const MIN: usize, const MAX: usize> From<OptionRangedUsize<MIN, MAX>> for Option<RangedUsize<MIN, MAX>>

fn from(value: OptionRangedUsize<MIN, MAX>) -> Option<RangedUsize<MIN, MAX>>

Converts to this type from the input type.

impl From<ProfileTag> for Option<Profile>

fn from(tag: ProfileTag) -> Option<Profile>

Converts to this type from the input type.

impl From<Span> for Option<Id>

fn from(span: Span) -> Option<Id>

Converts to this type from the input type.

impl<T> From<T> for Option<T>

fn from(val: T) -> Option<T>

Moves val into a new Some.

Examples

let o: Option<u8> = Option::from(67);

assert_eq!(Some(67), o);

impl<'a> FromBer<'a> for Option<Any<'a>>

fn from_ber(bytes: &'a [u8]) -> Result<(&'a [u8], Option<Any<'a>>), Err<Error>>

Attempt to parse input bytes into a BER object

impl<'a, T> FromBer<'a> for Option<T>

where T: FromBer<'a> + Tagged,

fn from_ber(bytes: &'a [u8]) -> Result<(&'a [u8], Option<T>), Err<Error>>

Attempt to parse input bytes into a BER object

impl FromBytes for Option<NonZero<i128>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<i16>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<i32>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<i64>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<i8>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<isize>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<u128>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<u16>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<u32>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<u64>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<u8>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl FromBytes for Option<NonZero<usize>>

fn ref_from(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the given bytes as a &Self without copying.

fn ref_from_prefix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the prefix of the given bytes as a &Self without copying.

fn ref_from_suffix(bytes: &[u8]) -> Option<&Self>

where Self: Sized,

Interprets the suffix of the given bytes as a &Self without copying.

fn mut_from(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut Self without copying.

fn mut_from_prefix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut Self without copying.

fn mut_from_suffix(bytes: &mut [u8]) -> Option<&mut Self>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut Self without copying.

fn slice_from(bytes: &[u8]) -> Option<&[Self]>

where Self: Sized,

Interprets the given bytes as a &[Self] without copying.

fn slice_from_prefix(bytes: &[u8], count: usize) -> Option<(&[Self], &[u8])>

where Self: Sized,

Interprets the prefix of the given bytes as a &[Self] with length equal to count without copying.

fn slice_from_suffix(bytes: &[u8], count: usize) -> Option<(&[u8], &[Self])>

where Self: Sized,

Interprets the suffix of the given bytes as a &[Self] with length equal to count without copying.

fn mut_slice_from(bytes: &mut [u8]) -> Option<&mut [Self]>

where Self: Sized + AsBytes,

Interprets the given bytes as a &mut [Self] without copying.

fn mut_slice_from_prefix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [Self], &mut [u8])>

where Self: Sized + AsBytes,

Interprets the prefix of the given bytes as a &mut [Self] with length equal to count without copying.

fn mut_slice_from_suffix( bytes: &mut [u8], count: usize, ) -> Option<(&mut [u8], &mut [Self])>

where Self: Sized + AsBytes,

Interprets the suffix of the given bytes as a &mut [Self] with length equal to count without copying.

fn read_from(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from bytes.

fn read_from_prefix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the prefix of bytes.

fn read_from_suffix(bytes: &[u8]) -> Option<Self>

where Self: Sized,

Reads a copy of Self from the suffix of bytes.

impl<'r, T: FromData<'r>> FromData<'r> for Option<T>

type Error = Infallible

The associated error to be returned when the guard fails.

fn from_data<'life0, 'async_trait>( req: &'r Request<'life0>, data: Data<'r>, ) -> Pin<Box<dyn Future<Output = Outcome<'r, Self>> + Send + 'async_trait>>

where Self: 'async_trait, 'r: 'async_trait, 'life0: 'async_trait,

Asynchronously validates, parses, and converts an instance of Self from the incoming request body data.

impl<'a> FromDer<'a> for Option<Any<'a>>

fn from_der(bytes: &'a [u8]) -> Result<(&'a [u8], Option<Any<'a>>), Err<Error>>

Attempt to parse input bytes into a DER object (enforcing constraints)

impl<'a, T> FromDer<'a> for Option<T>

where T: FromDer<'a> + Tagged,

fn from_der(bytes: &'a [u8]) -> Result<(&'a [u8], Option<T>), Err<Error>>

Attempt to parse input bytes into a DER object (enforcing constraints)

impl<'v, T: FromForm<'v>> FromForm<'v> for Option<T>

type Context = <T as FromForm<'v>>::Context

The form guard’s parsing context.

fn init(_: Options) -> Self::Context

Initializes and returns the parsing context for Self.

fn push_value(ctxt: &mut Self::Context, field: ValueField<'v>)

Processes the value field field.

fn push_data<'life0, 'life1, 'async_trait>( ctxt: &'life0 mut Self::Context, field: DataField<'v, 'life1>, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where Self: 'async_trait, 'v: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Processes the data field field.

fn finalize(this: Self::Context) -> Result<'v, Self>

Finalizes parsing. Returns the parsed value when successful or collection of Errors otherwise.

fn push_error(_ctxt: &mut Self::Context, _error: Error<'r>)

Processes the external form or field error _error.

fn default(opts: Options) -> Option<Self>

Returns a default value, if any, to use when a value is desired and parsing fails.

impl<A, V> FromIterator<Option<A>> for Option<V>

where V: FromIterator<A>,

fn from_iter<I>(iter: I) -> Option<V>

where I: IntoIterator<Item = Option<A>>,

Takes each element in the Iterator: if it is None, no further elements are taken, and the None is returned. Should no None occur, a container of type V containing the values of each Option is returned.

Examples

Here is an example which increments every integer in a vector. We use the checked variant of add that returns None when the calculation would result in an overflow.

let items = vec![0_u16, 1, 2];

let res: Option<Vec<u16>> = items
    .iter()
    .map(|x| x.checked_add(1))
    .collect();

assert_eq!(res, Some(vec![1, 2, 3]));

As you can see, this will return the expected, valid items.

Here is another example that tries to subtract one from another list of integers, this time checking for underflow:

let items = vec![2_u16, 1, 0];

let res: Option<Vec<u16>> = items
    .iter()
    .map(|x| x.checked_sub(1))
    .collect();

assert_eq!(res, None);

Since the last element is zero, it would underflow. Thus, the resulting value is None.

Here is a variation on the previous example, showing that no further elements are taken from iter after the first None.

let items = vec![3_u16, 2, 1, 10];

let mut shared = 0;

let res: Option<Vec<u16>> = items
    .iter()
    .map(|x| { shared += x; x.checked_sub(2) })
    .collect();

assert_eq!(res, None);
assert_eq!(shared, 6);

Since the third element caused an underflow, no further elements were taken, so the final value of shared is 6 (= 3 + 2 + 1), not 16.

impl<'a, T: FromParam<'a>> FromParam<'a> for Option<T>

type Error = Infallible

The associated error to be returned if parsing/validation fails.

fn from_param(param: &'a str) -> Result<Self, Self::Error>

Parses and validates an instance of Self from a path parameter string or returns an Error if parsing or validation fails.

impl<'r, T: FromRequest<'r>> FromRequest<'r> for Option<T>

type Error = Infallible

The associated error to be returned if derivation fails.

fn from_request<'life0, 'async_trait>( request: &'r Request<'life0>, ) -> Pin<Box<dyn Future<Output = Outcome<Self, Infallible>> + Send + 'async_trait>>

where Self: 'async_trait, 'r: 'async_trait, 'life0: 'async_trait,

Derives an instance of Self from the incoming request metadata.

impl<T> FromResidual<Option<Infallible>> for Option<T>

fn from_residual(residual: Option<Infallible>) -> Option<T>

🔬This is a nightly-only experimental API. (try_trait_v2)

Constructs the type from a compatible Residual type.

impl<T> FromResidual<Yeet<()>> for Option<T>

fn from_residual(_: Yeet<()>) -> Option<T>

🔬This is a nightly-only experimental API. (try_trait_v2)

Constructs the type from a compatible Residual type.

impl<'r, T: FromSegments<'r>> FromSegments<'r> for Option<T>

type Error = Infallible

The associated error to be returned when parsing fails.

fn from_segments(segments: Segments<'r, Path>) -> Result<Option<T>, Self::Error>

Parses an instance of Self from many dynamic path parameter strings or returns an Error if one cannot be parsed.

impl<A, T> FromUriParam<Path, A> for Option<T>

where T: FromUriParam<Path, A>,

A no cost conversion allowing any T to be used in place of an Option<T>.

type Target = <T as FromUriParam<Path, A>>::Target

The resulting type of this conversion.

fn from_uri_param(param: A) -> <Option<T> as FromUriParam<Path, A>>::Target

Converts a value of type T into a value of type Self::Target. The resulting value of type Self::Target will be rendered into a URI using its UriDisplay implementation.

impl<A, T> FromUriParam<Query, Option<A>> for Option<T>

where T: FromUriParam<Query, A>,

type Target = Option<<T as FromUriParam<Query, A>>::Target>

The resulting type of this conversion.

fn from_uri_param( param: Option<A>, ) -> <Option<T> as FromUriParam<Query, Option<A>>>::Target

Converts a value of type T into a value of type Self::Target. The resulting value of type Self::Target will be rendered into a URI using its UriDisplay implementation.

impl<A, E, T> FromUriParam<Query, Option<A>> for Result<T, E>

where T: FromUriParam<Query, A>,

type Target = Option<<T as FromUriParam<Query, A>>::Target>

The resulting type of this conversion.

fn from_uri_param( param: Option<A>, ) -> <Result<T, E> as FromUriParam<Query, Option<A>>>::Target

Converts a value of type T into a value of type Self::Target. The resulting value of type Self::Target will be rendered into a URI using its UriDisplay implementation.

impl<A, E, T> FromUriParam<Query, Result<A, E>> for Option<T>

where T: FromUriParam<Query, A>,

type Target = Result<<T as FromUriParam<Query, A>>::Target, E>

The resulting type of this conversion.

fn from_uri_param( param: Result<A, E>, ) -> <Option<T> as FromUriParam<Query, Result<A, E>>>::Target

Converts a value of type T into a value of type Self::Target. The resulting value of type Self::Target will be rendered into a URI using its UriDisplay implementation.

impl<T> FromZeroes for Option<&T>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<T> FromZeroes for Option<&mut T>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<T> FromZeroes for Option<NonNull<T>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<i128>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<i16>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<i32>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<i64>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<i8>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<isize>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<u128>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<u16>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<u32>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<u64>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<u8>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl FromZeroes for Option<NonZero<usize>>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<M> FromZeroes for Option<extern "C" fn() -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<A, B, C, D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<B, C, D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<C, D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<E, F, G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<F, G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<G, H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<H, I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<I, J, K, L, M> FromZeroes for Option<extern "C" fn(_: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<J, K, L, M> FromZeroes for Option<extern "C" fn(_: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<K, L, M> FromZeroes for Option<extern "C" fn(_: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<L, M> FromZeroes for Option<extern "C" fn(_: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<M> FromZeroes for Option<fn() -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<A, B, C, D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<B, C, D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<fn(_: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<C, D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<fn(_: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<D, E, F, G, H, I, J, K, L, M> FromZeroes for Option<fn(_: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<E, F, G, H, I, J, K, L, M> FromZeroes for Option<fn(_: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<F, G, H, I, J, K, L, M> FromZeroes for Option<fn(_: F, _: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<G, H, I, J, K, L, M> FromZeroes for Option<fn(_: G, _: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<H, I, J, K, L, M> FromZeroes for Option<fn(_: H, _: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<I, J, K, L, M> FromZeroes for Option<fn(_: I, _: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<J, K, L, M> FromZeroes for Option<fn(_: J, _: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<K, L, M> FromZeroes for Option<fn(_: K, _: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<L, M> FromZeroes for Option<fn(_: L) -> M>

fn zero(&mut self)

Overwrites self with zeroes.

fn new_zeroed() -> Self

where Self: Sized,

Creates an instance of Self from zeroed bytes.

impl<T> Hash for Option<T>

where T: Hash,

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

where __H: Hasher,

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> Interceptor for Option<T>

where T: Interceptor,

fn intercept_rx_remote_port(&mut self, subject: &Subject, port: &mut u16)

fn intercept_rx_payload<'a>( &mut self, subject: &Subject, packet: &Packet, payload: DecoderBufferMut<'a>, ) -> DecoderBufferMut<'a>

fn intercept_tx_payload( &mut self, subject: &Subject, packet: &Packet, payload: &mut Buffer<'_>, )

fn intercept_rx_ack<A>(&mut self, subject: &Subject, ack: &mut A)

where A: Ack,

fn intercept_rx_datagram<'a>( &mut self, subject: &Subject, datagram: &Datagram<'_>, payload: DecoderBufferMut<'a>, ) -> DecoderBufferMut<'a>

fn intercept_tx_datagram( &mut self, subject: &Subject, datagram: &Datagram<'_>, payload: &mut EncoderBuffer<'_>, )

impl<T, U> IntoEvent<Option<U>> for Option<T>

where T: IntoEvent<U>,

fn into_event(self) -> Option<U>

impl<'a, T> IntoIterator for &'a Option<T>

type Item = &'a T

The type of the elements being iterated over.

type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a, T>

Creates an iterator from a value.

impl<'a, T> IntoIterator for &'a mut Option<T>

type Item = &'a mut T

The type of the elements being iterated over.

type IntoIter = IterMut<'a, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> IterMut<'a, T>

Creates an iterator from a value.

impl<T> IntoIterator for Option<T>

fn into_iter(self) -> IntoIter<T>

Returns a consuming iterator over the possibly contained value.

Examples

let x = Some("string");
let v: Vec<&str> = x.into_iter().collect();
assert_eq!(v, ["string"]);

let x = None;
let v: Vec<&str> = x.into_iter().collect();
assert!(v.is_empty());

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

impl<S, E, F> IntoOutcome<Outcome<S, E, F>> for Option<S>

type Error = E

The type to use when returning an Outcome::Error.

type Forward = F

The type to use when returning an Outcome::Forward.

fn or_error(self, error: E) -> Outcome<S, E, F>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Error is returned with error as the inner value.

fn or_forward(self, forward: F) -> Outcome<S, E, F>

Converts self into an Outcome. If self represents a success, an Outcome::Success is returned. Otherwise, an Outcome::Forward is returned with forward as the inner value.

impl<T> IntoOwned for Option<T>

where T: IntoOwned,

type Owned = Option<<T as IntoOwned>::Owned>

The owned version of the type.

fn into_owned(self) -> <Option<T> as IntoOwned>::Owned

Converts self into an owned version of itself.

impl<L, S> Layer<S> for Option<L>

where L: Layer<S>, S: Subscriber,

fn on_layer(&mut self, subscriber: &mut S)

Performs late initialization when attaching a Layer to a Subscriber.

fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)

Notifies this layer that a new span was constructed with the given Attributes and Id.

fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest

Registers a new callsite with this layer, returning whether or not the layer is interested in being notified about the callsite, similarly to Subscriber::register_callsite.

fn enabled(&self, metadata: &Metadata<'_>, ctx: Context<'_, S>) -> bool

Returns true if this layer is interested in a span or event with the given metadata in the current Context, similarly to Subscriber::enabled.

fn on_record(&self, span: &Id, values: &Record<'_>, ctx: Context<'_, S>)

Notifies this layer that a span with the given Id recorded the given values.

fn on_follows_from(&self, span: &Id, follows: &Id, ctx: Context<'_, S>)

Notifies this layer that a span with the ID span recorded that it follows from the span with the ID follows.

fn event_enabled(&self, event: &Event<'_>, ctx: Context<'_, S>) -> bool

Called before on_event, to determine if on_event should be called.

fn on_event(&self, event: &Event<'_>, ctx: Context<'_, S>)

Notifies this layer that an event has occurred.

fn on_enter(&self, id: &Id, ctx: Context<'_, S>)

Notifies this layer that a span with the given ID was entered.

fn on_exit(&self, id: &Id, ctx: Context<'_, S>)

Notifies this layer that the span with the given ID was exited.

fn on_close(&self, id: Id, ctx: Context<'_, S>)

Notifies this layer that the span with the given ID has been closed.

fn on_id_change(&self, old: &Id, new: &Id, ctx: Context<'_, S>)

Notifies this layer that a span ID has been cloned, and that the subscriber returned a different ID.

fn on_register_dispatch(&self, subscriber: &Dispatch)

Performs late initialization when installing this layer as a Subscriber.

fn and_then<L>(self, layer: L) -> Layered<L, Self, S>

where L: Layer<S>, Self: Sized,

Composes this layer around the given Layer, returning a Layered struct implementing Layer.

fn with_subscriber(self, inner: S) -> Layered<Self, S>

where Self: Sized,

Composes this Layer with the given Subscriber, returning a Layered struct that implements Subscriber.

fn with_filter<F>(self, filter: F) -> Filtered<Self, F, S>

where Self: Sized, F: Filter<S>,

Combines self with a Filter, returning a Filtered layer.

fn boxed(self) -> Box<dyn Layer<S> + Send + Sync>

where Self: Sized + Layer<S> + Send + Sync + 'static, S: Subscriber,

Erases the type of this Layer, returning a Boxed dyn Layer trait object.

impl<L, T: Len<L>> Len<L> for Option<T>

fn len(&self) -> L

The length of the value.

fn len_into_u64(len: L) -> u64

Convert len into u64.

fn zero_len() -> L

The zero value for L.

impl<R> NominalRecorder for Option<R>

where R: NominalRecorder,

fn record<T>(&self, info: &'static Info, variant: &'static Variant, value: T)

where T: Metric,

impl<T> Ord for Option<T>

where T: Ord,

fn cmp(&self, other: &Option<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 for Option<T>

where T: PartialEq,

fn eq(&self, other: &Option<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 for Option<T>

where T: PartialOrd,

fn partial_cmp(&self, other: &Option<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<P> Path for Option<P>

where P: Path,

fn on_path_secrets_ready( &mut self, session: &impl TlsSession, ) -> Result<Vec<Token>, Error>

Called when path secrets are ready to be derived from the given TlsSession

fn on_peer_stateless_reset_tokens<'a>( &mut self, stateless_reset_tokens: impl Iterator<Item = &'a Token>, )

Called when a DC_STATELESS_RESET_TOKENS frame has been received from the peer

fn on_dc_handshake_complete(&mut self)

Called when the peer has confirmed receipt of DC_STATELESS_RESET_TOKENS, either by the server sending back its own DC_STATELESS_RESET_TOKENS or by the client acknowledging the DC_STATELESS_RESET_TOKENS frame was received.

fn on_mtu_updated(&mut self, max_datagram_size: u16)

Called when the MTU has been updated for the path

impl<T, U> Product<Option<U>> for Option<T>

where T: Product<U>,

fn product<I>(iter: I) -> Option<T>

where I: Iterator<Item = Option<U>>,

Takes each element in the Iterator: if it is a None, no further elements are taken, and the None is returned. Should no None occur, the product of all elements is returned.

Examples

This multiplies each number in a vector of strings, if a string could not be parsed the operation returns None:

let nums = vec!["5", "10", "1", "2"];
let total: Option<usize> = nums.iter().map(|w| w.parse::<usize>().ok()).product();
assert_eq!(total, Some(100));
let nums = vec!["5", "10", "one", "2"];
let total: Option<usize> = nums.iter().map(|w| w.parse::<usize>().ok()).product();
assert_eq!(total, None);

impl<T> Provider for Option<T>

where T: Provider,

fn timers<Q>(&self, query: &mut Q) -> Result<(), QueryBreak>

where Q: Query,

Notifies the query of any timers owned by the provider

fn next_expiration(&self) -> Option<Timestamp>

Returns the next Timestamp at which the earliest timer is armed in the provider

fn is_armed(&self) -> bool

Returns true if there are any timers armed

fn armed_timer_count(&self) -> usize

Counts the number of armed timers in the provider

fn for_each_timer<F>(&self, f: F)

where F: FnMut(&Timer) -> Result<(), QueryBreak>,

Iterates over each timer in the provider and calls the provided function

impl Query for Option<Timestamp>

Implement Query for Option<Timestamp> to make it easy to get the earliest armed timestamp

fn on_timer(&mut self, timer: &Timer) -> Result<(), QueryBreak>

Called for each timer owned by the provider

impl<R> Recorder for Option<R>

where R: Recorder,

fn record<T>(&self, info: &'static Info, value: T)

where T: Metric,

impl<T> Residual<T> for Option<Infallible>

type TryType = Option<T>

🔬This is a nightly-only experimental API. (try_trait_v2_residual)

The “return” type of this meta-function.

impl<'r, 'o: 'r, R: Responder<'r, 'o>> Responder<'r, 'o> for Option<R>

If self is Some, responds with the wrapped Responder. Otherwise prints a warning message and returns an Err of Status::NotFound.

fn respond_to(self, req: &'r Request<'_>) -> Result<'o>

Returns Ok if a Response could be generated successfully. Otherwise, returns an Err with a failing Status.

impl<T: Sentinel> Sentinel for Option<T>

fn abort(rocket: &Rocket<Ignite>) -> bool

Returns true if launch should be aborted and false otherwise.

impl<T> Serialize for Option<T>

where T: Serialize,

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.

impl<T> Show for Option<T>

where T: Show,

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

impl<T> Strategy for Option<T>

where T: Strategy,

fn havoc<R>(&mut self, rand: &mut R, buffer: &mut EncoderBuffer<'_>)

where R: Random,

Applies the havoc strategy to the supplied buffer

fn havoc_slice<R>(&mut self, rand: &mut R, buffer: &mut [u8]) -> usize

where R: Random,

Applies the havoc strategy to the supplied buffer slice and returns the new buffer length

fn havoc_u16<R>(&mut self, rand: &mut R, input: u16) -> u16

where R: Random,

Applies the havoc strategy to the given u16 value and returns the new u16 result

fn alternate<B>(self, b: B, period: Range<usize>) -> Alternate<Self, B>

where B: Strategy,

Alternate between two strategies with the supplied period

fn repeat(self, count: Range<usize>) -> Repeat<Self>

Apply the strategy count times

fn randomly(self) -> Randomly<Self>

Randomly apply the strategy

fn toggle(self, period: Range<usize>) -> Toggle<Self>

Toggle the strategy on and off for the supplied period

fn and_then<B>(self, b: B) -> AndThen<Self, B>

where B: Strategy,

Applies two strategies in order

fn while_has_capacity(self) -> WhileHasCapacity<Self>

Repeatedly applies the strategy as long as the buffer has capacity

fn hold(self, count: Range<usize>) -> Hold<Self>

Applies the strategy and holds the result count times

impl<T, U> Sum<Option<U>> for Option<T>

where T: Sum<U>,

fn sum<I>(iter: I) -> Option<T>

where I: Iterator<Item = Option<U>>,

Takes each element in the Iterator: if it is a None, no further elements are taken, and the None is returned. Should no None occur, the sum of all elements is returned.

Examples

This sums up the position of the character ‘a’ in a vector of strings, if a word did not have the character ‘a’ the operation returns None:

let words = vec!["have", "a", "great", "day"];
let total: Option<usize> = words.iter().map(|w| w.find('a')).sum();
assert_eq!(total, Some(5));
let words = vec!["have", "a", "good", "day"];
let total: Option<usize> = words.iter().map(|w| w.find('a')).sum();
assert_eq!(total, None);

impl<T> ToDer for Option<T>

where T: ToDer,

fn to_der_len(&self) -> Result<usize, Error>

Get the length of the object (including the header), when encoded

fn write_der_header( &self, writer: &mut dyn Write, ) -> Result<usize, SerializeError>

Attempt to write the DER header to this writer.

fn write_der_content( &self, writer: &mut dyn Write, ) -> Result<usize, SerializeError>

Attempt to write the DER content (all except header) to this writer.

fn to_der_vec(&self) -> Result<Vec<u8>, SerializeError>

Write the DER encoded representation to a newly allocated Vec<u8>.

fn to_der_vec_raw(&self) -> Result<Vec<u8>, SerializeError>

Similar to using to_vec, but uses provided values without changes. This can generate an invalid encoding for a DER object.

fn write_der(&self, writer: &mut dyn Write) -> Result<usize, SerializeError>

Attempt to write the DER encoded representation (header and content) into this writer.

fn write_der_raw(&self, writer: &mut dyn Write) -> Result<usize, SerializeError>

Similar to using to_der, but uses provided values without changes. This can generate an invalid encoding for a DER object.

impl TransportParameter for Option<InitialSourceConnectionId>

const ID: VarInt = <InitialSourceConnectionId as TransportParameter>::ID

The ID or tag for the TransportParameter

type CodecValue = InitialSourceConnectionId

Associated type for decoding/encoding the TransportParameter

fn from_codec_value( value: <Option<InitialSourceConnectionId> as TransportParameter>::CodecValue, ) -> Option<InitialSourceConnectionId>

Create a TransportParameter from the CodecValue

fn try_into_codec_value( &self, ) -> Option<&<Option<InitialSourceConnectionId> as TransportParameter>::CodecValue>

Attempts to convert the TransportParameter into the CodecValue

fn default_value() -> Option<InitialSourceConnectionId>

Returns the default value for the TransportParameter This is used instead of Default::default so it is easily overridable

const ENABLED: bool = true

Enables/disables the TransportParameter in a certain context

fn append_to_buffer(&self, buffer: &mut Vec<u8>)

Appends this TransportParameter to the given buffer containing already encoded TransportParameters

impl TransportParameter for Option<OriginalDestinationConnectionId>

const ID: VarInt = <OriginalDestinationConnectionId as TransportParameter>::ID

The ID or tag for the TransportParameter

type CodecValue = OriginalDestinationConnectionId

Associated type for decoding/encoding the TransportParameter

fn from_codec_value( value: <Option<OriginalDestinationConnectionId> as TransportParameter>::CodecValue, ) -> Option<OriginalDestinationConnectionId>

Create a TransportParameter from the CodecValue

fn try_into_codec_value( &self, ) -> Option<&<Option<OriginalDestinationConnectionId> as TransportParameter>::CodecValue>

Attempts to convert the TransportParameter into the CodecValue

fn default_value() -> Option<OriginalDestinationConnectionId>

Returns the default value for the TransportParameter This is used instead of Default::default so it is easily overridable

const ENABLED: bool = true

Enables/disables the TransportParameter in a certain context

fn append_to_buffer(&self, buffer: &mut Vec<u8>)

Appends this TransportParameter to the given buffer containing already encoded TransportParameters

impl TransportParameter for Option<PreferredAddress>

const ID: VarInt = <PreferredAddress as TransportParameter>::ID

The ID or tag for the TransportParameter

type CodecValue = PreferredAddress

Associated type for decoding/encoding the TransportParameter

fn from_codec_value( value: <Option<PreferredAddress> as TransportParameter>::CodecValue, ) -> Option<PreferredAddress>

Create a TransportParameter from the CodecValue

fn try_into_codec_value( &self, ) -> Option<&<Option<PreferredAddress> as TransportParameter>::CodecValue>

Attempts to convert the TransportParameter into the CodecValue

fn default_value() -> Option<PreferredAddress>

Returns the default value for the TransportParameter This is used instead of Default::default so it is easily overridable

const ENABLED: bool = true

Enables/disables the TransportParameter in a certain context

fn append_to_buffer(&self, buffer: &mut Vec<u8>)

Appends this TransportParameter to the given buffer containing already encoded TransportParameters

impl TransportParameter for Option<RetrySourceConnectionId>

const ID: VarInt = <RetrySourceConnectionId as TransportParameter>::ID

The ID or tag for the TransportParameter

type CodecValue = RetrySourceConnectionId

Associated type for decoding/encoding the TransportParameter

fn from_codec_value( value: <Option<RetrySourceConnectionId> as TransportParameter>::CodecValue, ) -> Option<RetrySourceConnectionId>

Create a TransportParameter from the CodecValue

fn try_into_codec_value( &self, ) -> Option<&<Option<RetrySourceConnectionId> as TransportParameter>::CodecValue>

Attempts to convert the TransportParameter into the CodecValue

fn default_value() -> Option<RetrySourceConnectionId>

Returns the default value for the TransportParameter This is used instead of Default::default so it is easily overridable

const ENABLED: bool = true

Enables/disables the TransportParameter in a certain context

fn append_to_buffer(&self, buffer: &mut Vec<u8>)

Appends this TransportParameter to the given buffer containing already encoded TransportParameters

impl TransportParameter for Option<Token>

const ID: VarInt = <stateless_reset::Token as TransportParameter>::ID

The ID or tag for the TransportParameter

type CodecValue = Token

Associated type for decoding/encoding the TransportParameter

fn from_codec_value( value: <Option<Token> as TransportParameter>::CodecValue, ) -> Option<Token>

Create a TransportParameter from the CodecValue

fn try_into_codec_value( &self, ) -> Option<&<Option<Token> as TransportParameter>::CodecValue>

Attempts to convert the TransportParameter into the CodecValue

fn default_value() -> Option<Token>

Returns the default value for the TransportParameter This is used instead of Default::default so it is easily overridable

const ENABLED: bool = true

Enables/disables the TransportParameter in a certain context

fn append_to_buffer(&self, buffer: &mut Vec<u8>)

Appends this TransportParameter to the given buffer containing already encoded TransportParameters

impl TransportParameterValidator for Option<InitialSourceConnectionId>

fn validate(self) -> Result<Option<InitialSourceConnectionId>, DecoderError>

Validates that the transport parameter is in a valid state

impl TransportParameterValidator for Option<OriginalDestinationConnectionId>

fn validate( self, ) -> Result<Option<OriginalDestinationConnectionId>, DecoderError>

Validates that the transport parameter is in a valid state

impl TransportParameterValidator for Option<PreferredAddress>

fn validate(self) -> Result<Option<PreferredAddress>, DecoderError>

Validates that the transport parameter is in a valid state

impl TransportParameterValidator for Option<RetrySourceConnectionId>

fn validate(self) -> Result<Option<RetrySourceConnectionId>, DecoderError>

Validates that the transport parameter is in a valid state

impl TransportParameterValidator for Option<Token>

fn validate(self) -> Result<Option<Token>, DecoderError>

Validates that the transport parameter is in a valid state

impl<T> Try for Option<T>

type Output = T

🔬This is a nightly-only experimental API. (try_trait_v2)

The type of the value produced by ? when not short-circuiting.

type Residual = Option<Infallible>

🔬This is a nightly-only experimental API. (try_trait_v2)

The type of the value passed to FromResidual::from_residual as part of ? when short-circuiting.

fn from_output(output: <Option<T> as Try>::Output) -> Option<T>

🔬This is a nightly-only experimental API. (try_trait_v2)

Constructs the type from its Output type.

fn branch( self, ) -> ControlFlow<<Option<T> as Try>::Residual, <Option<T> as Try>::Output>

🔬This is a nightly-only experimental API. (try_trait_v2)

Used in ? to decide whether the operator should produce a value (because this returned ControlFlow::Continue) or propagate a value back to the caller (because this returned ControlFlow::Break).

impl<T> UriDisplay<Query> for Option<T>

where T: UriDisplay<Query>,

Defers to the UriDisplay<Query> implementation for T.

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

Formats self in a URI-safe manner using the given formatter.

impl<T> Value for Option<T>

where T: Value,

fn record(&self, key: &Field, visitor: &mut dyn Visit)

Visits this value with the given Visitor.

impl<Z> Zeroize for Option<Z>

where Z: Zeroize,

fn zeroize(&mut self)

Zero out this object from memory using Rust intrinsics which ensure the zeroization operation is not “optimized away” by the compiler.

impl<T> Copy for Option<T>

where T: Copy,

impl<T> Eq for Option<T>

where T: Eq,

impl<T> Ignorable<Query> for Option<T>

impl<T> StructuralPartialEq for Option<T>

impl Unaligned for Option<NonZero<i8>>

impl Unaligned for Option<NonZero<u8>>

impl<Z> ZeroizeOnDrop for Option<Z>

where Z: ZeroizeOnDrop,