Struct gclient :: ext :: sp_core :: bounded :: alloc :: boxed :: Box Copy item path

impl<T> Box<T>

1.0.0 · source

pub fn new(x: T) -> Box<T>

Allocates memory on the heap and then places x into it.

This doesn’t actually allocate if T is zero-sized.

§Examples

let five = Box::new(5);

pub fn new_uninit() -> Box<MaybeUninit<T>>

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

Constructs a new box with uninitialized contents.

§Examples

#![feature(new_uninit)]

let mut five = Box::<u32>::new_uninit();

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

pub fn new_zeroed() -> Box<MaybeUninit<T>>

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

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(new_uninit)]

let zero = Box::<u32>::new_zeroed();
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0)

1.33.0 · source

pub fn pin(x: T) -> Pin<Box<T>>

Constructs a new Pin<Box<T>>. If T does not implement Unpin, then x will be pinned in memory and unable to be moved.

Constructing and pinning of the Box can also be done in two steps: Box::pin(x) does the same as Box::into_pin(Box::new(x)). Consider using into_pin if you already have a Box<T>, or if you want to construct a (pinned) Box in a different way than with Box::new.

pub fn try_new(x: T) -> Result<Box<T>, AllocError>

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

Allocates memory on the heap then places x into it, returning an error if the allocation fails

This doesn’t actually allocate if T is zero-sized.

§Examples

#![feature(allocator_api)]

let five = Box::try_new(5)?;

pub fn try_new_uninit() -> Result<Box<MaybeUninit<T>>, AllocError>

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

Constructs a new box with uninitialized contents on the heap, returning an error if the allocation fails

§Examples

#![feature(allocator_api, new_uninit)]

let mut five = Box::<u32>::try_new_uninit()?;

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5);

pub fn try_new_zeroed() -> Result<Box<MaybeUninit<T>>, AllocError>

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

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes on the heap

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(allocator_api, new_uninit)]

let zero = Box::<u32>::try_new_zeroed()?;
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0);

impl<T, A> Box<T, A>
where A: Allocator,

pub fn new_in(x: T, alloc: A) -> Box<T, A>
where A: Allocator,

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

Allocates memory in the given allocator then places x into it.

This doesn’t actually allocate if T is zero-sized.

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let five = Box::new_in(5, System);

pub fn try_new_in(x: T, alloc: A) -> Result<Box<T, A>, AllocError>
where A: Allocator,

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

Allocates memory in the given allocator then places x into it, returning an error if the allocation fails

This doesn’t actually allocate if T is zero-sized.

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let five = Box::try_new_in(5, System)?;

pub fn new_uninit_in(alloc: A) -> Box<MaybeUninit<T>, A>
where A: Allocator,

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

Constructs a new box with uninitialized contents in the provided allocator.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let mut five = Box::<u32, _>::new_uninit_in(System);

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

pub fn try_new_uninit_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>
where A: Allocator,

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

Constructs a new box with uninitialized contents in the provided allocator, returning an error if the allocation fails

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let mut five = Box::<u32, _>::try_new_uninit_in(System)?;

let five = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5);

pub fn new_zeroed_in(alloc: A) -> Box<MaybeUninit<T>, A>
where A: Allocator,

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

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes in the provided allocator.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let zero = Box::<u32, _>::new_zeroed_in(System);
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0)

pub fn try_new_zeroed_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>
where A: Allocator,

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

Constructs a new Box with uninitialized contents, with the memory being filled with 0 bytes in the provided allocator, returning an error if the allocation fails,

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let zero = Box::<u32, _>::try_new_zeroed_in(System)?;
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0);

pub fn pin_in(x: T, alloc: A) -> Pin<Box<T, A>>
where A: 'static + Allocator,

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

Constructs a new Pin<Box<T, A>>. If T does not implement Unpin, then x will be pinned in memory and unable to be moved.

Constructing and pinning of the Box can also be done in two steps: Box::pin_in(x, alloc) does the same as Box::into_pin(Box::new_in(x, alloc)). Consider using into_pin if you already have a Box<T, A>, or if you want to construct a (pinned) Box in a different way than with Box::new_in.

pub fn into_boxed_slice(boxed: Box<T, A>) -> Box<[T], A>

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

Converts a Box<T> into a Box<[T]>

This conversion does not allocate on the heap and happens in place.

pub fn into_inner(boxed: Box<T, A>) -> T

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

Consumes the Box, returning the wrapped value.

§Examples

#![feature(box_into_inner)]

let c = Box::new(5);

assert_eq!(Box::into_inner(c), 5);

impl<T> Box<[T]>

pub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>]>

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

Constructs a new boxed slice with uninitialized contents.

§Examples

#![feature(new_uninit)]

let mut values = Box::<[u32]>::new_uninit_slice(3);

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3])

pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>]>

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

Constructs a new boxed slice with uninitialized contents, with the memory being filled with 0 bytes.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(new_uninit)]

let values = Box::<[u32]>::new_zeroed_slice(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0])

pub fn try_new_uninit_slice( len: usize, ) -> Result<Box<[MaybeUninit<T>]>, AllocError>

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

Constructs a new boxed slice with uninitialized contents. Returns an error if the allocation fails.

§Examples

#![feature(allocator_api, new_uninit)]

let mut values = Box::<[u32]>::try_new_uninit_slice(3)?;
let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);
    values.assume_init()
};

assert_eq!(*values, [1, 2, 3]);

pub fn try_new_zeroed_slice( len: usize, ) -> Result<Box<[MaybeUninit<T>]>, AllocError>

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

Constructs a new boxed slice with uninitialized contents, with the memory being filled with 0 bytes. Returns an error if the allocation fails.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(allocator_api, new_uninit)]

let values = Box::<[u32]>::try_new_zeroed_slice(3)?;
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0]);

impl<T, A> Box<[T], A>
where A: Allocator,

pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>

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

Constructs a new boxed slice with uninitialized contents in the provided allocator.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System);

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3])

pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>

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

Constructs a new boxed slice with uninitialized contents in the provided allocator, with the memory being filled with 0 bytes.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let values = Box::<[u32], _>::new_zeroed_slice_in(3, System);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0])

pub fn try_new_uninit_slice_in( len: usize, alloc: A, ) -> Result<Box<[MaybeUninit<T>], A>, AllocError>

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

Constructs a new boxed slice with uninitialized contents in the provided allocator. Returns an error if the allocation fails.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let mut values = Box::<[u32], _>::try_new_uninit_slice_in(3, System)?;
let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);
    values.assume_init()
};

assert_eq!(*values, [1, 2, 3]);

pub fn try_new_zeroed_slice_in( len: usize, alloc: A, ) -> Result<Box<[MaybeUninit<T>], A>, AllocError>

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

Constructs a new boxed slice with uninitialized contents in the provided allocator, with the memory being filled with 0 bytes. Returns an error if the allocation fails.

See MaybeUninit::zeroed for examples of correct and incorrect usage of this method.

§Examples

#![feature(allocator_api, new_uninit)]

use std::alloc::System;

let values = Box::<[u32], _>::try_new_zeroed_slice_in(3, System)?;
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0]);

impl<T, A> Box<MaybeUninit<T>, A>
where A: Allocator,

pub unsafe fn assume_init(self) -> Box<T, A>

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

Converts to Box<T, A>.

§Safety

As with MaybeUninit::assume_init, it is up to the caller to guarantee that the value really is in an initialized state. Calling this when the content is not yet fully initialized causes immediate undefined behavior.

§Examples

#![feature(new_uninit)]

let mut five = Box::<u32>::new_uninit();

let five: Box<u32> = unsafe {
    // Deferred initialization:
    five.as_mut_ptr().write(5);

    five.assume_init()
};

assert_eq!(*five, 5)

pub fn write(boxed: Box<MaybeUninit<T>, A>, value: T) -> Box<T, A>

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

Writes the value and converts to Box<T, A>.

This method converts the box similarly to Box::assume_init but writes value into it before conversion thus guaranteeing safety. In some scenarios use of this method may improve performance because the compiler may be able to optimize copying from stack.

§Examples

#![feature(new_uninit)]

let big_box = Box::<[usize; 1024]>::new_uninit();

let mut array = [0; 1024];
for (i, place) in array.iter_mut().enumerate() {
    *place = i;
}

// The optimizer may be able to elide this copy, so previous code writes
// to heap directly.
let big_box = Box::write(big_box, array);

for (i, x) in big_box.iter().enumerate() {
    assert_eq!(*x, i);
}

impl<T, A> Box<[MaybeUninit<T>], A>
where A: Allocator,

pub unsafe fn assume_init(self) -> Box<[T], A>

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

Converts to Box<[T], A>.

§Safety

As with MaybeUninit::assume_init, it is up to the caller to guarantee that the values really are in an initialized state. Calling this when the content is not yet fully initialized causes immediate undefined behavior.

§Examples

#![feature(new_uninit)]

let mut values = Box::<[u32]>::new_uninit_slice(3);

let values = unsafe {
    // Deferred initialization:
    values[0].as_mut_ptr().write(1);
    values[1].as_mut_ptr().write(2);
    values[2].as_mut_ptr().write(3);

    values.assume_init()
};

assert_eq!(*values, [1, 2, 3])

impl<T> Box<T>
where T: ?Sized,

1.4.0 · source

pub unsafe fn from_raw(raw: *mut T) -> Box<T>

Constructs a box from a raw pointer.

After calling this function, the raw pointer is owned by the resulting Box. Specifically, the Box destructor will call the destructor of T and free the allocated memory. For this to be safe, the memory must have been allocated in accordance with the memory layout used by Box .

§Safety

This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.

The safety conditions are described in the memory layout section.

§Examples

Recreate a Box which was previously converted to a raw pointer using Box::into_raw:

let x = Box::new(5);
let ptr = Box::into_raw(x);
let x = unsafe { Box::from_raw(ptr) };

Manually create a Box from scratch by using the global allocator:

use std::alloc::{alloc, Layout};

unsafe {
    let ptr = alloc(Layout::new::<i32>()) as *mut i32;
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `ptr`, though for this
    // simple example `*ptr = 5` would have worked as well.
    ptr.write(5);
    let x = Box::from_raw(ptr);
}

impl<T, A> Box<T, A>
where A: Allocator, T: ?Sized,

pub const unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Box<T, A>

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

Constructs a box from a raw pointer in the given allocator.

After calling this function, the raw pointer is owned by the resulting Box. Specifically, the Box destructor will call the destructor of T and free the allocated memory. For this to be safe, the memory must have been allocated in accordance with the memory layout used by Box .

§Safety

This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.

§Examples

Recreate a Box which was previously converted to a raw pointer using Box::into_raw_with_allocator:

#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(5, System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };

Manually create a Box from scratch by using the system allocator:

#![feature(allocator_api, slice_ptr_get)]

use std::alloc::{Allocator, Layout, System};

unsafe {
    let ptr = System.allocate(Layout::new::<i32>())?.as_mut_ptr() as *mut i32;
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `ptr`, though for this
    // simple example `*ptr = 5` would have worked as well.
    ptr.write(5);
    let x = Box::from_raw_in(ptr, System);
}

1.4.0 · source

pub fn into_raw(b: Box<T, A>) -> *mut T

Consumes the Box, returning a wrapped raw pointer.

The pointer will be properly aligned and non-null.

After calling this function, the caller is responsible for the memory previously managed by the Box. In particular, the caller should properly destroy T and release the memory, taking into account the memory layout used by Box. The easiest way to do this is to convert the raw pointer back into a Box with the Box::from_raw function, allowing the Box destructor to perform the cleanup.

Note: this is an associated function, which means that you have to call it as Box::into_raw(b) instead of b.into_raw(). This is so that there is no conflict with a method on the inner type.

§Examples

Converting the raw pointer back into a Box with Box::from_raw for automatic cleanup:

let x = Box::new(String::from("Hello"));
let ptr = Box::into_raw(x);
let x = unsafe { Box::from_raw(ptr) };

Manual cleanup by explicitly running the destructor and deallocating the memory:

use std::alloc::{dealloc, Layout};
use std::ptr;

let x = Box::new(String::from("Hello"));
let ptr = Box::into_raw(x);
unsafe {
    ptr::drop_in_place(ptr);
    dealloc(ptr as *mut u8, Layout::new::<String>());
}

Note: This is equivalent to the following:

let x = Box::new(String::from("Hello"));
let ptr = Box::into_raw(x);
unsafe {
    drop(Box::from_raw(ptr));
}

pub fn into_raw_with_allocator(b: Box<T, A>) -> (*mut T, A)

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

Consumes the Box, returning a wrapped raw pointer and the allocator.

The pointer will be properly aligned and non-null.

After calling this function, the caller is responsible for the memory previously managed by the Box. In particular, the caller should properly destroy T and release the memory, taking into account the memory layout used by Box. The easiest way to do this is to convert the raw pointer back into a Box with the Box::from_raw_in function, allowing the Box destructor to perform the cleanup.

Note: this is an associated function, which means that you have to call it as Box::into_raw_with_allocator(b) instead of b.into_raw_with_allocator(). This is so that there is no conflict with a method on the inner type.

§Examples

Converting the raw pointer back into a Box with Box::from_raw_in for automatic cleanup:

#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };

Manual cleanup by explicitly running the destructor and deallocating the memory:

#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};
use std::ptr::{self, NonNull};

let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
unsafe {
    ptr::drop_in_place(ptr);
    let non_null = NonNull::new_unchecked(ptr);
    alloc.deallocate(non_null.cast(), Layout::new::<String>());
}

pub const fn allocator(b: &Box<T, A>) -> &A

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

Returns a reference to the underlying allocator.

Note: this is an associated function, which means that you have to call it as Box::allocator(&b) instead of b.allocator(). This is so that there is no conflict with a method on the inner type.

1.26.0 · source

pub fn leak<'a>(b: Box<T, A>) -> &'a mut T
where A: 'a,

Consumes and leaks the Box, returning a mutable reference, &'a mut T.

Note that the type T must outlive the chosen lifetime 'a. If the type has only static references, or none at all, then this may be chosen to be 'static.

This function is mainly useful for data that lives for the remainder of the program’s life. Dropping the returned reference will cause a memory leak. If this is not acceptable, the reference should first be wrapped with the Box::from_raw function producing a Box. This Box can then be dropped which will properly destroy T and release the allocated memory.

Note: this is an associated function, which means that you have to call it as Box::leak(b) instead of b.leak(). This is so that there is no conflict with a method on the inner type.

§Examples

Simple usage:

let x = Box::new(41);
let static_ref: &'static mut usize = Box::leak(x);
*static_ref += 1;
assert_eq!(*static_ref, 42);

Unsized data:

let x = vec![1, 2, 3].into_boxed_slice();
let static_ref = Box::leak(x);
static_ref[0] = 4;
assert_eq!(*static_ref, [4, 2, 3]);

1.63.0 (const: unstable) · source

pub fn into_pin(boxed: Box<T, A>) -> Pin<Box<T, A>>
where A: 'static,

Converts a Box<T> into a Pin<Box<T>>. If T does not implement Unpin, then *boxed will be pinned in memory and unable to be moved.

This conversion does not allocate on the heap and happens in place.

This is also available via From.

Constructing and pinning a Box with Box::into_pin(Box::new(x)) can also be written more concisely using Box::pin(x). This into_pin method is useful if you already have a Box<T>, or you are constructing a (pinned) Box in a different way than with Box::new.

§Notes

It’s not recommended that crates add an impl like From<Box<T>> for Pin<T>, as it’ll introduce an ambiguity when calling Pin::from. A demonstration of such a poor impl is shown below.

struct Foo; // A type defined in this crate.
impl From<Box<()>> for Pin<Foo> {
    fn from(_: Box<()>) -> Pin<Foo> {
        Pin::new(Foo)
    }
}

let foo = Box::new(());
let bar = Pin::from(foo);

impl<A> Box<dyn Any, A>
where A: Allocator,

1.0.0 · source

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any, A>>
where T: Any,

Attempts to downcast the box to a concrete type.

§Examples

use std::any::Any;

fn print_if_string(value: Box<dyn Any>) {
    if let Ok(string) = value.downcast::<String>() {
        println!("String ({}): {}", string.len(), string);
    }
}

let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));

pub unsafe fn downcast_unchecked<T>(self) -> Box<T, A>
where T: Any,

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

Downcasts the box to a concrete type.

For a safe alternative see downcast.

§Examples

#![feature(downcast_unchecked)]

use std::any::Any;

let x: Box<dyn Any> = Box::new(1_usize);

unsafe {
    assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}

§Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

impl<A> Box<dyn Any + Send, A>
where A: Allocator,

1.0.0 · source

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any + Send, A>>
where T: Any,

Attempts to downcast the box to a concrete type.

§Examples

use std::any::Any;

fn print_if_string(value: Box<dyn Any + Send>) {
    if let Ok(string) = value.downcast::<String>() {
        println!("String ({}): {}", string.len(), string);
    }
}

let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));

pub unsafe fn downcast_unchecked<T>(self) -> Box<T, A>
where T: Any,

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

Downcasts the box to a concrete type.

For a safe alternative see downcast.

§Examples

#![feature(downcast_unchecked)]

use std::any::Any;

let x: Box<dyn Any + Send> = Box::new(1_usize);

unsafe {
    assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}

§Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

impl<A> Box<dyn Any + Send + Sync, A>
where A: Allocator,

1.51.0 · source

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any + Send + Sync, A>>
where T: Any,

Attempts to downcast the box to a concrete type.

§Examples

use std::any::Any;

fn print_if_string(value: Box<dyn Any + Send + Sync>) {
    if let Ok(string) = value.downcast::<String>() {
        println!("String ({}): {}", string.len(), string);
    }
}

let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));

pub unsafe fn downcast_unchecked<T>(self) -> Box<T, A>
where T: Any,

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

Downcasts the box to a concrete type.

For a safe alternative see downcast.

§Examples

#![feature(downcast_unchecked)]

use std::any::Any;

let x: Box<dyn Any + Send + Sync> = Box::new(1_usize);

unsafe {
    assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}

§Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

Trait Implementations§

1.64.0 · source§

impl<T> AsFd for Box<T>
where T: AsFd + ?Sized,

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor. Read more

1.5.0 · source§

impl<T, A> AsMut<T> for Box<T, A>
where A: Allocator, T: ?Sized,

fn as_mut(&mut self) -> &mut T

Converts this type into a mutable reference of the (usually inferred) input type.

1.63.0 · source§

impl<T> AsRawFd for Box<T>
where T: AsRawFd,

fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor. Read more

1.5.0 · source§

impl<Args, F, A> AsyncFnOnce<Args> for Box<F, A>
where Args: Tuple, F: AsyncFnOnce<Args> + ?Sized, A: Allocator,

type Output = <F as AsyncFnOnce<Args>>::Output

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

Output type of the called closure’s future.

type CallOnceFuture = <F as AsyncFnOnce<Args>>::CallOnceFuture

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

Future returned by AsyncFnOnce::async_call_once.

extern "rust-call" fn async_call_once( self, args: Args, ) -> <Box<F, A> as AsyncFnOnce<Args>>::CallOnceFuture

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

Call the AsyncFnOnce, returning a future which may move out of the called closure.

impl<S> AsyncIterator for Box<S>
where S: AsyncIterator + Unpin + ?Sized,

type Item = <S as AsyncIterator>::Item

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

The type of items yielded by the async iterator.

fn poll_next( self: Pin<&mut Box<S>>, cx: &mut Context<'_>, ) -> Poll<Option<<Box<S> as AsyncIterator>::Item>>

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

Attempts to pull out the next value of this async iterator, registering the current task for wakeup if the value is not yet available, and returning None if the async iterator is exhausted. Read more

fn size_hint(&self) -> (usize, Option<usize>)

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

Returns the bounds on the remaining length of the async iterator. Read more

impl<T> AsyncRead for Box<T>
where T: AsyncRead + Unpin + ?Sized,

fn poll_read( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, buf: &mut [u8], ) -> Poll<Result<usize, Error>>

Attempt to read from the AsyncRead into buf. Read more

Waits for a seek operation to complete. Read more

impl<T> AsyncWrite for Box<T>
where T: AsyncWrite + Unpin + ?Sized,

fn poll_write( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from buf into the object. Read more

fn poll_write_vectored( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from bufs into the object using vectored IO operations. Read more

fn poll_flush( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

fn poll_close( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>

Attempt to close the object. Read more

type Data = <T as Body>::Data

Values yielded by the Body.

type Error = <T as Body>::Error

The error type this Body might generate.

fn poll_frame( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, ) -> Poll<Option<Result<Frame<<Box<T> as Body>::Data>, <Box<T> as Body>::Error>>>

Attempt to pull out the next data buffer of this stream.

fn is_end_stream(&self) -> bool

Returns true when the end of stream has been reached. Read more

Creates an adaptor which implements the Read trait for self. Read more

Creates an adapter which will chain this buffer with another. Read more

1.0.0 · source§

impl BufRead for Box
where B: BufRead + ?Sized,

fn fill_buf(&mut self) -> Result<&[u8], Error>

Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more

fn consume(&mut self, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to read. Read more

fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes into buf until the delimiter byte or EOF is reached. Read more

fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until a newline (the 0xA byte) is reached, and append them to the provided String buffer. Read more

fn has_data_left(&mut self) -> Result<bool, Error>

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

Checks if the underlying Read has any data left to be read. Read more

fn skip_until(&mut self, byte: u8) -> Result<usize, Error>

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

Skips all bytes until the delimiter byte or EOF is reached. Read more

1.0.0 · source§

fn split(self, byte: u8) -> Split<Self> ⓘ
where Self: Sized,

Returns an iterator over the contents of this reader split on the byte byte. Read more

1.0.0 · source§

fn lines(self) -> Lines<Self> ⓘ
where Self: Sized,

Returns an iterator over the lines of this reader. Read more

§Examples

let x = Box::new(5);
let y = x.clone();

// The value is the same
assert_eq!(x, y);

// But they are unique objects
assert_ne!(&*x as *const i32, &*y as *const i32);

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

Copies source’s contents into self without creating a new allocation.

§Examples

let x = Box::new(5);
let mut y = Box::new(10);
let yp: *const i32 = &*y;

y.clone_from(&x);

// The value is the same
assert_eq!(x, y);

// And no allocation occurred
assert_eq!(yp, &*y);

impl<G, R, A> Coroutine<R> for Box<G, A>
where G: Coroutine<R> + Unpin + ?Sized, A: Allocator,

type Yield = <G as Coroutine<R>>::Yield

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

The type of value this coroutine yields. Read more

type Return = <G as Coroutine<R>>::Return

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

The type of value this coroutine returns. Read more

fn resume( self: Pin<&mut Box<G, A>>, arg: R, ) -> CoroutineState<<Box<G, A> as Coroutine<R>>::Yield, <Box<G, A> as Coroutine<R>>::Return>

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

Resumes the execution of this coroutine. Read more

impl<G, R, A> Coroutine<R> for Pin<Box<G, A>>
where G: Coroutine<R> + ?Sized, A: Allocator + 'static,

type Yield = <G as Coroutine<R>>::Yield

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

The type of value this coroutine yields. Read more

type Return = <G as Coroutine<R>>::Return

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

The type of value this coroutine returns. Read more

fn resume( self: Pin<&mut Pin<Box<G, A>>>, arg: R, ) -> CoroutineState<<Pin<Box<G, A>> as Coroutine<R>>::Yield, <Pin<Box<G, A>> as Coroutine<R>>::Return>

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

Resumes the execution of this coroutine. Read more

impl<T> DbExternalities for Box<T>
where T: DbExternalities + ?Sized,

fn local_storage_set(&mut self, kind: StorageKind, key: &[u8], value: &[u8])

Sets a value in the local storage. Read more

fn local_storage_clear(&mut self, kind: StorageKind, key: &[u8])

Removes a value in the local storage. Read more

fn local_storage_compare_and_set( &mut self, kind: StorageKind, key: &[u8], old_value: Option<&[u8]>, new_value: &[u8], ) -> bool

fn try_rfold<B, E, F>(&mut self, init: B, f: F) -> Result<B, E>
where Self: Sized, E: From<Self::Error>, F: FnMut(B, Self::Item) -> Result<B, E>,

Applies a function over the elements of the iterator in reverse, producing a single final value. Read more

1.0.0 · source§

impl<I, A> DoubleEndedIterator for Box<I, A>
where I: DoubleEndedIterator + ?Sized, A: Allocator,

fn next_back(&mut self) -> Option<::Item>

Removes and returns an element from the end of the iterator. Read more

fn nth_back(&mut self, n: usize) -> Option<::Item>

Returns the nth element from the end of the iterator. Read more

fn advance_back_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

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

Advances the iterator from the back by n elements. Read more

1.27.0 · source§

fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R
where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

This is the reverse version of Iterator::try_fold(): it takes elements starting from the back of the iterator. Read more

1.27.0 · source§

fn rfold<B, F>(self, init: B, f: F) -> B
where Self: Sized, F: FnMut(B, Self::Item) -> B,

An iterator method that reduces the iterator’s elements to a single, final value, starting from the back. Read more

This is a helper function which internally calls [EncodeAsFields::encode_as_fields_to]. Prefer to implement that instead.

impl<T> EncodeAsType for Box<T>
where T: EncodeAsType,

fn encode_as_type_to<R>( &self, type_id: <R as TypeResolver>::TypeId, types: &R, out: &mut Vec<u8>, ) -> Result<(), Error>
where R: TypeResolver,

Given some type_id, types, a context and some output target for the SCALE encoded bytes, attempt to SCALE encode the current value into the type given by type_id.

fn encode_as_type<R>( &self, type_id: <R as TypeResolver>::TypeId, types: &R, ) -> Result<Vec<u8>, Error>
where R: TypeResolver,

This is a helper function which internally calls [EncodeAsType::encode_as_type_to]. Prefer to implement that instead.

Raised when a Deserialize struct type received more than one of the same field.

fn provide<'b>(&'b self, request: &mut Request<'b>)

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

Provides type-based access to context intended for error reports. Read more

1.0.0 · source§

impl<I, A> ExactSizeIterator for Box<I, A>
where I: ExactSizeIterator + ?Sized, A: Allocator,

fn len(&self) -> usize

Returns the exact remaining length of the iterator. Read more

fn is_empty(&self) -> bool

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

Returns true if the iterator is empty. Read more

1.45.0 · source§

impl<A> Extend<Box<str, A>> for String
where A: Allocator,

fn extend(&mut self, iter: I)
where I: IntoIterator<Item = Box<str, A>>,

Extends a collection with the contents of an iterator. Read more

fn extend_one(&mut self, item: A)

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

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

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

Reserves capacity in a collection for the given number of additional elements. Read more

fn as_mut_any(&mut self) -> &mut (dyn Any + 'static)

Return the extension as &mut dyn Any. Read more

fn type_id(&self) -> TypeId

Get the TypeId of this Extension.

Set the authorized nodes from runtime. Read more

extern "rust-call" fn call( &self, args: Args, ) -> <Box<F, A> as FnOnce<Args>>::Output

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

Performs the call operation.

1.35.0 · source§

impl<Args, F, A> FnMut<Args> for Box<F, A>
where Args: Tuple, F: FnMut<Args> + ?Sized, A: Allocator,

extern "rust-call" fn call_mut( &mut self, args: Args, ) -> <Box<F, A> as FnOnce<Args>>::Output

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

Performs the call operation.

1.35.0 · source§

impl<Args, F, A> FnOnce<Args> for Box<F, A>
where Args: Tuple, F: FnOnce<Args> + ?Sized, A: Allocator,

type Output = <F as FnOnce<Args>>::Output

The returned type after the call operator is used.

extern "rust-call" fn call_once( self, args: Args, ) -> <Box<F, A> as FnOnce<Args>>::Output

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

Performs the call operation.

1.17.0 · source§

impl<T> From<&[T]> for Box<[T]>
where T: Clone,

fn from(slice: &[T]) -> Box<[T]>

Converts a &[T] into a Box<[T]>

This conversion allocates on the heap and performs a copy of slice and its contents.

§Examples

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice: Box<[u8]> = Box::from(slice);

println!("{boxed_slice:?}");

1.17.0 · source§

impl From<&CStr> for Box<CStr>

fn from(s: &CStr) -> Box<CStr>

Converts a &CStr into a Box<CStr>, by copying the contents into a newly allocated Box.

1.17.0 · source§

impl From<&OsStr> for Box<OsStr>

fn from(s: &OsStr) -> Box<OsStr>

Copies the string into a newly allocated Box<OsStr>.

fn from(s: &str) -> Box<str>

Converts a &str into a Box<str>

This conversion allocates on the heap and performs a copy of s.

§Examples

let boxed: Box<str> = Box::from("hello");
println!("{boxed}");

1.45.0 · source§

impl<T, const N: usize> From<[T; N]> for Box<[T]>

fn from(array: [T; N]) -> Box<[T]>

Converts a [T; N] into a Box<[T]>

This conversion moves the array to newly heap-allocated memory.

§Examples

let boxed: Box<[u8]> = Box::from([4, 2]);
println!("{boxed:?}");

§Examples

let b: Box<[i32]> = vec![1, 2, 3].into_boxed_slice();
assert_eq!(Vec::from(b), vec![1, 2, 3]);

impl<T, O> From<Box<T>> for BitBox<T, O>
where T: BitStore, O: BitOrder,

fn from(elem: Box<T>) -> BitBox<T, O>

Converts to this type from the input type.

1.21.0 · source§

impl<T, A> From<Box<T, A>> for Arc<T, A>
where A: Allocator, T: ?Sized,

fn from(v: Box<T, A>) -> Arc<T, A>

Move a boxed object to a new, reference-counted allocation.

§Example

let unique: Box<str> = Box::from("eggplant");
let shared: Arc<str> = Arc::from(unique);
assert_eq!("eggplant", &shared[..]);

1.33.0 · source§

impl<T, A> From<Box<T, A>> for Pin<Box<T, A>>
where A: Allocator + 'static, T: ?Sized,

fn from(boxed: Box<T, A>) -> Pin<Box<T, A>>

Converts a Box<T> into a Pin<Box<T>>. If T does not implement Unpin, then *boxed will be pinned in memory and unable to be moved.

This conversion does not allocate on the heap and happens in place.

This is also available via Box::into_pin.

Constructing and pinning a Box with <Pin<Box<T>>>::from(Box::new(x)) can also be written more concisely using Box::pin(x). This From implementation is useful if you already have a Box<T>, or you are constructing a (pinned) Box in a different way than with Box::new.

1.21.0 · source§

Converts the given boxed str slice to a String. It is notable that the str slice is owned.

§Examples

let s1: String = String::from("hello world");
let s2: Box<str> = s1.into_boxed_str();
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

1.19.0 · source§

impl<A> From<Box<str, A>> for Box<[u8], A>
where A: Allocator,

fn from(s: Box<str, A>) -> Box<[u8], A>

Converts a Box<str> into a Box<[u8]>

This conversion does not allocate on the heap and happens in place.

§Examples

// create a Box<str> which will be used to create a Box<[u8]>
let boxed: Box<str> = Box::from("hello");
let boxed_str: Box<[u8]> = Box::from(boxed);

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice = Box::from(slice);

assert_eq!(boxed_slice, boxed_str);

1.20.0 · source§

impl From<CString> for Box<CStr>

fn from(s: CString) -> Box<CStr>

Converts a CString into a Box<CStr> without copying or allocating.

impl From<ColoredString> for Box<dyn Error>

fn from(cs: ColoredString) -> Box<dyn Error>

Converts to this type from the input type.

impl From<Cow<'_, OsStr>> for Box<OsStr>

fn from(cow: Cow<'_, OsStr>) -> Box<OsStr>

Converts a Cow<'a, OsStr> into a Box<OsStr>, by copying the contents if they are borrowed.

1.45.0 · source§

impl From<Cow<'_, Path>> for Box<Path>

fn from(cow: Cow<'_, Path>) -> Box<Path>

Creates a boxed Path from a clone-on-write pointer.

Converting from a Cow::Owned does not clone or allocate.

1.45.0 · source§

impl From<Cow<'_, str>> for Box<str>

fn from(cow: Cow<'_, str>) -> Box<str>

Converts a Cow<'_, str> into a Box<str>

When cow is the Cow::Borrowed variant, this conversion allocates on the heap and copies the underlying str. Otherwise, it will try to reuse the owned String’s allocation.

§Examples

use std::borrow::Cow;

let unboxed = Cow::Borrowed("hello");
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");

let unboxed = Cow::Owned("hello".to_string());
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");

1.22.0 · source§

impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + 'a>

fn from(err: Cow<'b, str>) -> Box<dyn Error + 'a>

Converts a Cow into a box of dyn Error.

§Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

1.22.0 · source§

impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a>

fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>

Converts a Cow into a box of dyn Error + Send + Sync.

§Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

1.0.0 · source§

impl<'a, E> From<E> for Box<dyn Error + 'a>
where E: Error + 'a,

fn from(err: E) -> Box<dyn Error + 'a>

Converts a type of Error into a box of dyn Error.

§Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "An error")
    }
}

impl Error for AnError {}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error>::from(an_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

1.0.0 · source§

Converts a PathBuf into a Box<Path>.

let s1: String = String::from("hello world");
let s2: Box<str> = Box::from(s1);
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

1.6.0 · source§

impl<T> From<T> for Box<T>

fn from(t: T) -> Box<T>

Converts a T into a Box<T>

The conversion allocates on the heap and moves t from the stack into it.

§Examples

let x = 5;
let boxed = Box::new(5);

assert_eq!(Box::from(x), boxed);

1.20.0 · source§

impl<T, A> From<Vec<T, A>> for Box<[T], A>
where A: Allocator,

fn from(v: Vec<T, A>) -> Box<[T], A>

Converts a vector into a boxed slice.

Before doing the conversion, this method discards excess capacity like Vec::shrink_to_fit.

§Examples

assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());

Any excess capacity is removed:

let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3]);

assert_eq!(Box::from(vec), vec![1, 2, 3].into_boxed_slice());

fn poll( self: Pin<&mut Box<F, A>>, cx: &mut Context<'_>, ) -> Poll<<Box<F, A> as Future>::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available. Read more

1.0.0 · source§

impl<T, A> Hash for Box<T, A>
where T: Hash + ?Sized, A: Allocator,

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

Feeds this value into the given Hasher. Read more

1.3.0 · source§

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

Feeds a slice of this type into the given Hasher. Read more

1.22.0 · source§

Writes a single isize into this hasher.

fn write_length_prefix(&mut self, len: usize)

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

Writes a length prefix into this hasher, as part of being prefix-free. Read more

fn write_str(&mut self, s: &str)

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

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

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source§

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more

1.0.0 · source§

fn count(self) -> usize
where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

1.0.0 · source§

fn last(self) -> Option<Self::Item>
where Self: Sized,

Consumes the iterator, returning the last element. Read more

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

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

1.0.0 · source§

fn fuse(self) -> Fuse<Self> ⓘ
where Self: Sized,

Creates an iterator which ends after the first None. Read more

1.0.0 · source§

fn inspect<F>(self, f: F) -> Inspect<Self, F> ⓘ
where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more

1.0.0 · source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Borrows an iterator, rather than consuming it. Read more

1.0.0 · source§

fn collect(self) -> B
where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection. Read more

fn collect_into<E>(self, collection: &mut E) -> &mut E
where E: Extend<Self::Item>, Self: Sized,

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

Collects all the items from an iterator into a collection. Read more

1.0.0 · source§

fn partition<B, F>(self, f: F) -> (B, B)
where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

fn is_partitioned(self, predicate: P) -> bool
where Self: Sized, P: FnMut(Self::Item) -> bool,

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

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false. Read more

1.27.0 · source§

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more

1.27.0 · source§

fn try_for_each<F, R>(&mut self, f: F) -> R
where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more

1.0.0 · source§

fn fold<B, F>(self, init: B, f: F) -> B
where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result. Read more

1.51.0 · source§

fn reduce<F>(self, f: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType
where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source§

fn all<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source§

fn any<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source§

fn find(&mut self, predicate: P) -> Option<Self::Item>
where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source§

fn find_map<B, F>(&mut self, f: F) -> Option
where Self: Sized, F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns the first non-none result. Read more

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType
where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Applies function to the elements of iterator and returns the first true result or the first error. Read more

1.0.0 · source§

fn position(&mut self, predicate: P) -> Option<usize>
where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more

1.6.0 · source§

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>
where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function. Read more

1.15.0 · source§

fn max_by<F>(self, compare: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function. Read more

1.6.0 · source§

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>
where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function. Read more

1.15.0 · source§

fn min_by<F>(self, compare: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function. Read more

1.0.0 · source§

fn cycle(self) -> Cycle<Self> ⓘ
where Self: Sized + Clone,

Repeats an iterator endlessly. Read more

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N> ⓘ
where Self: Sized,

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

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source§

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

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source§

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more

1.0.0 · source§

fn count(self) -> usize
where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

1.0.0 · source§

fn last(self) -> Option<Self::Item>
where Self: Sized,

Consumes the iterator, returning the last element. Read more

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

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

1.0.0 · source§

fn fuse(self) -> Fuse<Self> ⓘ
where Self: Sized,

Creates an iterator which ends after the first None. Read more

1.0.0 · source§

fn inspect<F>(self, f: F) -> Inspect<Self, F> ⓘ
where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more

1.0.0 · source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Borrows an iterator, rather than consuming it. Read more

1.0.0 · source§

fn collect(self) -> B
where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection. Read more

fn collect_into<E>(self, collection: &mut E) -> &mut E
where E: Extend<Self::Item>, Self: Sized,

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

Collects all the items from an iterator into a collection. Read more

1.0.0 · source§

fn partition<B, F>(self, f: F) -> (B, B)
where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

fn is_partitioned(self, predicate: P) -> bool
where Self: Sized, P: FnMut(Self::Item) -> bool,

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

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false. Read more

1.27.0 · source§

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more

1.27.0 · source§

fn try_for_each<F, R>(&mut self, f: F) -> R
where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more

1.0.0 · source§

fn fold<B, F>(self, init: B, f: F) -> B
where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result. Read more

1.51.0 · source§

fn reduce<F>(self, f: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType
where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source§

fn all<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source§

fn any<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source§

fn find(&mut self, predicate: P) -> Option<Self::Item>
where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source§

fn find_map<B, F>(&mut self, f: F) -> Option
where Self: Sized, F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns the first non-none result. Read more

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType
where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Applies function to the elements of iterator and returns the first true result or the first error. Read more

1.0.0 · source§

fn position(&mut self, predicate: P) -> Option<usize>
where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more

1.6.0 · source§

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>
where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function. Read more

1.15.0 · source§

fn max_by<F>(self, compare: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function. Read more

1.6.0 · source§

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>
where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function. Read more

1.15.0 · source§

fn min_by<F>(self, compare: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function. Read more

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N> ⓘ
where Self: Sized,

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

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source§

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

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source§

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more

1.0.0 · source§

fn count(self) -> usize
where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

1.0.0 · source§

fn last(self) -> Option<Self::Item>
where Self: Sized,

Consumes the iterator, returning the last element. Read more

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

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

1.0.0 · source§

fn fuse(self) -> Fuse<Self> ⓘ
where Self: Sized,

Creates an iterator which ends after the first None. Read more

1.0.0 · source§

fn inspect<F>(self, f: F) -> Inspect<Self, F> ⓘ
where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more

1.0.0 · source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Borrows an iterator, rather than consuming it. Read more

1.0.0 · source§

fn collect(self) -> B
where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection. Read more

fn collect_into<E>(self, collection: &mut E) -> &mut E
where E: Extend<Self::Item>, Self: Sized,

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

Collects all the items from an iterator into a collection. Read more

1.0.0 · source§

fn partition<B, F>(self, f: F) -> (B, B)
where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

fn is_partitioned(self, predicate: P) -> bool
where Self: Sized, P: FnMut(Self::Item) -> bool,

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

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false. Read more

1.27.0 · source§

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more

1.27.0 · source§

fn try_for_each<F, R>(&mut self, f: F) -> R
where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more

1.0.0 · source§

fn fold<B, F>(self, init: B, f: F) -> B
where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result. Read more

1.51.0 · source§

fn reduce<F>(self, f: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType
where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source§

fn all<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source§

fn any<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source§

fn find(&mut self, predicate: P) -> Option<Self::Item>
where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source§

fn find_map<B, F>(&mut self, f: F) -> Option
where Self: Sized, F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns the first non-none result. Read more

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType
where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Applies function to the elements of iterator and returns the first true result or the first error. Read more

1.0.0 · source§

fn position(&mut self, predicate: P) -> Option<usize>
where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more

1.6.0 · source§

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>
where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function. Read more

1.15.0 · source§

fn max_by<F>(self, compare: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function. Read more

1.6.0 · source§

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>
where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function. Read more

1.15.0 · source§

fn min_by<F>(self, compare: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function. Read more

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N> ⓘ
where Self: Sized,

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

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source§

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source§

fn count(self) -> usize
where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

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

Advances the iterator by n elements. Read more

1.28.0 · source§

fn step_by(self, step: usize) -> StepBy<Self> ⓘ
where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration. Read more

1.0.0 · source§

fn chain(self, other: U) -> Chain<Self, ::IntoIter> ⓘ
where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence. Read more

1.0.0 · source§

fn zip(self, other: U) -> Zip<Self, ::IntoIter> ⓘ
where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs. Read more

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G> ⓘ
where Self: Sized, G: FnMut() -> Self::Item,

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

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

fn partition<B, F>(self, f: F) -> (B, B)
where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

fn is_partitioned(self, predicate: P) -> bool
where Self: Sized, P: FnMut(Self::Item) -> bool,

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

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false. Read more

1.27.0 · source§

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more

1.27.0 · source§

fn try_for_each<F, R>(&mut self, f: F) -> R
where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more

1.0.0 · source§

fn fold<B, F>(self, init: B, f: F) -> B
where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result. Read more

1.51.0 · source§

fn reduce<F>(self, f: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType
where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

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

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source§

fn all<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source§

fn any<F>(&mut self, f: F) -> bool
where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source§

fn find(&mut self, predicate: P) -> Option<Self::Item>
where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source§

fn find_map<B, F>(&mut self, f: F) -> Option
where Self: Sized, F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns the first non-none result. Read more

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType
where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N> ⓘ
where Self: Sized,

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

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source§

fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more

1.0.0 · source§

impl<T, A> PartialEq for Box<T, A>
where T: PartialEq + ?Sized, A: Allocator,

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

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

fn ne(&self, other: &Box<T, A>) -> bool

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

1.0.0 · source§

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

Pull some bytes from this source into the specified buffer. Read more

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers. Read more

fn is_read_vectored(&self) -> bool

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

Determines if this Reader has an efficient read_vectored implementation. Read more

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf. Read more

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf. Read more

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf. Read more

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

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

Reads the exact number of bytes required to fill cursor. Read more

1.0.0 · source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adaptor for this instance of Read. Read more

1.0.0 · source§

fn bytes(self) -> Bytes<Self> ⓘ
where Self: Sized,

Transforms this Read instance to an Iterator over its bytes. Read more

1.0.0 · source§

fn chain<R>(self, next: R) -> Chain<Self, R>
where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another. Read more

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream. Read more

fn stream_len(&mut self) -> Result<u64, Error>

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

Returns the length of this stream (in bytes). Read more

Errors produced by the service.

type Future = <S as Service<Request>>::Future

The future response value.

fn call(&self, req: Request) -> <Box<S> as Service<Request>>::Future

Process the request and return the response asynchronously. call takes &self instead of mut &self because: Read more

fn register( &mut self, registry: &Registry, token: Token, interests: Interest, ) -> Result<(), Error>

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream. Read more

Notifies the subscriber that a span ID has been dropped, and returns true if there are now 0 IDs that refer to that span. Read more

fn drop_span(&self, id: Id)

👎Deprecated since 0.1.2: use Subscriber::try_close instead

This method is deprecated. Read more

fn current_span(&self) -> Current

type Error = Box<[T]>

The type returned in the event of a conversion error.

1.66.0 · source§

impl<T, const N: usize> TryFrom<Vec<T>> for Box<[T; N]>

fn try_from( vec: Vec<T>, ) -> Result<Box<[T; N]>, <Box<[T; N]> as TryFrom<Vec<T>>>::Error>

Attempts to convert a Vec<T> into a Box<[T; N]>.

Like Vec::into_boxed_slice, this is in-place if vec.capacity() == N, but will require a reallocation otherwise.

§Errors

Returns the original Vec<T> in the Err variant if boxed_slice.len() does not equal N.

§Examples

This can be used with vec! to create an array on the heap:

let state: Box<[f32; 100]> = vec![1.0; 100].try_into().unwrap();
assert_eq!(state.len(), 100);

Visits the [Operator] op using the given offset. Read more

fn visit_operator( &mut self, op: &Operator<'a>, ) -> <Box<V> as VisitOperator<'a>>::Output

Visits the [Operator] op using the given offset. Read more

A wrapped type.

fn write(&mut self, buf: &[u8]) -> Result<usize, Error>

Writes a buffer into this writer, returning how many bytes were written. Read more

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers. Read more

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation. Read more

fn flush(&mut self) -> Result<(), Error>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer. Read more

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

Writes a formatted string into this writer, returning any error encountered. Read more

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

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

Attempts to write multiple buffers into this writer. Read more

1.0.0 · source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more

impl<T> WriteColor for Box<T>
where T: WriteColor + ?Sized,

fn supports_color(&self) -> bool

Returns true if and only if the underlying writer supports colors.

fn set_color(&mut self, spec: &ColorSpec) -> Result<(), Error>

Set the color settings of the writer. Read more

fn reset(&mut self) -> Result<(), Error>

Reset the current color settings to their original settings. Read more

impl<Z> ZeroizeOnDrop for Box<[Z]>
where Z: ZeroizeOnDrop,

impl<T> Any for T
where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

fn as_filelike(&self) -> BorrowedFd<'_>

Borrows the reference. Read more

fn as_filelike_view<Target>(&self) -> FilelikeView<'_, Target>
where Target: FilelikeViewType,

Return a borrowing view of a resource which dereferences to a &Target. Read more

impl<A, T> AsMutBits<T> for A
where A: AsMut<[T]>, T: BitStore,

fn as_mut_bits<O>(&mut self) -> &mut BitSlice<T, O> ⓘ
where O: BitOrder,

Views self as a mutable bit-slice region with the O ordering.

fn try_as_mut_bits<O>(&mut self) -> Result<&mut BitSlice<T, O>, BitSpanError<T>>
where O: BitOrder,

Attempts to view self as a mutable bit-slice region with the O ordering. Read more

Returns the raw value.

impl<T> AsRawSocketlike for T
where T: AsRawFd,

fn as_raw_socketlike(&self) -> i32

Returns the raw value.

impl AsSliceOf for U
where U: AsRef<[u8]> + ?Sized,

fn as_slice_of<T>(&self) -> Result<&[T], Error>
where T: FromByteSlice,

impl<T> AsSocketlike for T
where T: AsFd,

fn as_socketlike(&self) -> BorrowedFd<'_>

Borrows the reference.

fn as_socketlike_view<Target>(&self) -> SocketlikeView<'_, Target>
where Target: SocketlikeViewType,

Return a borrowing view of a resource which dereferences to a &Target. Read more

Creates an AsyncRead adapter which will read at most limit bytes from the underlying reader. Read more

fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>
where Self: Unpin,

Creates a future which will seek an IO object, and then yield the new position in the object and the object itself. Read more

fn stream_position(&mut self) -> Seek<'_, Self>
where Self: Unpin,

Creates a future which will return the current seek position from the start of the stream. Read more

impl<S> AsyncSeekExt for S
where S: AsyncSeek + ?Sized,

fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>
where Self: Unpin,

Creates a future which will seek an IO object, and then yield the new position in the object and the object itself. Read more

fn rewind(&mut self) -> Seek<'_, Self>
where Self: Unpin,

Creates a future which will rewind to the beginning of the stream. Read more

fn stream_position(&mut self) -> Seek<'_, Self>
where Self: Unpin,

Creates a future which will return the current seek position from the start of the stream. Read more

Allow using an [AsyncWrite] as a Sink<Item: AsRef<[u8]>>. Read more

default fn get_hash<H, B>(value: &H, build_hasher: &B) -> u64
where H: Hash + ?Sized, B: BuildHasher,

impl<T> CheckedConversion for T

fn checked_from<T>(t: T) -> Option<Self>
where Self: TryFrom<T>,

Convert from a value of T into an equivalent instance of Option<Self>. Read more

fn checked_into<T>(self) -> Option<T>
where Self: TryInto<T>,

Consume self to return Some equivalent value of Option<T>. Read more

impl<T> Clear for T
where T: Default + Eq + PartialEq,

fn is_clear(&self) -> bool

True iff no bits are set.

fn clear() -> T

Return the value of Self that is clear.

fn decode_into( input: &mut I, dst: &mut MaybeUninit<Self>, ) -> Result<DecodeFinished, Error>
where I: Input,

Attempt to deserialize the value from input into a pre-allocated piece of memory. Read more

fn skip(input: &mut I) -> Result<(), Error>
where I: Input,

Attempt to skip the encoded value from input. Read more

fn encoded_fixed_size() -> Option<usize>

Returns the fixed encoded size of the type. Read more

impl<T> DecodeAll for T
where T: Decode,

fn decode_all(input: &mut &[u8]) -> Result<T, Error>

Decode Self and consume all of the given input data. Read more

impl<T> DecodeAsType for T
where T: IntoVisitor,

fn decode_as_type_maybe_compact<R>( input: &mut &[u8], type_id: <R as TypeResolver>::TypeId, types: &R, is_compact: bool, ) -> Result<T, Error>
where R: TypeResolver,

fn decode_as_type<R>( input: &mut &[u8], type_id: <R as TypeResolver>::TypeId, types: &R, ) -> Result<Self, Error>
where R: TypeResolver,

Given some input bytes, a type_id, and type registry, attempt to decode said bytes into Self. Implementations should modify the &mut reference to the bytes such that any bytes not used in the course of decoding are still pointed to after decoding is complete.

impl<T> DecodeLimit for T
where T: Decode,

fn decode_all_with_depth_limit( limit: u32, input: &mut &[u8], ) -> Result<T, Error>

Decode Self and consume all of the given input data. Read more

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.

impl<T> DowncastSync for T
where T: Any + Send + Sync,

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Send + Sync>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.

impl<T> DynClone for T
where T: Clone,

fn __clone_box(&self, _: Private) -> *mut ()

Check whether processing batch of messages identified by corresponding message_ids resulted in errors or has been successful. Read more

impl<F, S> FilterExt<S> for F
where F: Filter<S>,

fn and(self, other: B) -> And<Self, B, S>
where Self: Sized, B: Filter<S>,

Combines this Filter with another Filter s so that spans and events are enabled if and only if both filters return true. Read more

fn or(self, other: B) -> Or<Self, B, S>
where Self: Sized, B: Filter<S>,

Combines two Filters so that spans and events are enabled if either filter returns true. Read more

fn not(self) -> Not<Self, S>
where Self: Sized,

Inverts self, returning a filter that enables spans and events only if self would not enable them. Read more

fn boxed(self) -> Box<dyn Filter<S> + Send + Sync>
where Self: Sized + Send + Sync + 'static,

Boxes self, erasing its concrete type. Read more

The error type that can occur within this Service. Read more

type Future = <T as Service<Request<B1>>>::Future

The Future returned by this Service.

fn call(&mut self, req: Request<B1>) -> <T as HttpService<B1>>::Future

impl<T> Instrument for T

fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more

fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self> ⓘ
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more

impl IntoFallibleIterator for I
where I: FallibleIterator,

type Item = ::Item

The elements of the iterator.

type Error = ::Error

The error value of the iterator.

type IntoFallibleIter = I

The iterator.

fn into_fallible_iter(self) -> I

Creates a fallible iterator from a value.

The output that the future will produce on completion.

type IntoFuture = F

fn choose_multiple<R>(self, rng: &mut R, amount: usize) -> Vec<Self::Item>
where R: Rng + ?Sized,

Collects amount values at random from the iterator into a vector. Read more

👎Deprecated since 0.8.0: Use std .step_by() instead

Return an iterator adaptor that steps n elements in the base iterator for each iteration. Read more

fn map_into<R>(self) -> MapSpecialCase<Self, MapSpecialCaseFnInto<R>>
where Self: Sized, Self::Item: Into<R>,

Convert each item of the iterator using the Into trait. Read more

fn map_results<F, T, U, E>( self, f: F, ) -> MapSpecialCase<Self, MapSpecialCaseFnOk<F>>
where Self: Sized + Iterator<Item = Result<T, E>>, F: FnMut(T) -> U,

👎Deprecated since 0.10.0: Use .map_ok() instead

👎Deprecated since 0.8.0: Use .for_each() instead

👎Deprecated since 0.10.0: Use .fold_ok() instead

See .fold_ok().

fn fold_ok<A, E, B, F>(&mut self, start: B, f: F) -> Result<B, E>
where Self: Iterator<Item = Result<A, E>>, F: FnMut(B, A) -> B,

Fold Result values from an iterator. Read more

fn fold_options<A, B, F>(&mut self, start: B, f: F) -> Option
where Self: Iterator<Item = Option<A>>, F: FnMut(B, A) -> B,

Fold Option values from an iterator. Read more

fn fold1<F>(self, f: F) -> Option<Self::Item>
where F: FnMut(Self::Item, Self::Item) -> Self::Item, Self: Sized,

👎Deprecated since 0.10.2: Use Iterator::reduce instead

Spawns a task that polls the given future to completion and returns a future that resolves to the spawned future’s output. Read more

impl<T, M> MakeExt<T> for M
where M: MakeVisitor<T> + Sealed<MakeExtMarker<T>>,

fn debug_alt(self) -> Alt<Self>

Wraps self so that any fmt::Debug fields are recorded using the alternate formatter ({:#?}).

fn display_messages(self) -> Messages<Self>

Wraps self so that any string fields named “message” are recorded using fmt::Display.

fn delimited<D>(self, delimiter: D) -> Delimited<D, Self>
where D: AsRef<str> + Clone, Self::Visitor: VisitFmt,

Wraps self so that when fields are formatted to a writer, they are separated by the provided delimiter.

type Visitor = V

The visitor type produced by this MakeVisitor.

fn make_visitor(&self, target: T) -> <F as MakeVisitor<T>>::Visitor

Make a new visitor for the provided target.

impl<'a, F, W> MakeWriter<'a> for F
where F: Fn() -> W, W: Write,

type Writer = W

The concrete io::Write implementation returned by make_writer.

fn make_writer(&'a self) -> <F as MakeWriter<'a>>::Writer

Returns an instance of Writer. Read more

fn make_writer_for(&'a self, meta: &Metadata<'_>) -> Self::Writer

Returns a Writer for writing data from the span or event described by the provided Metadata. Read more

Write a single byte to the output.

impl<S> ParseFormatted for S
where S: AsRef<str>,

fn parse_formatted<F, N>(&self, format: &F) -> Result<N, Error>
where F: Format, N: FromFormattedStr,

Converts self (typically a formatted string) into a number (see Examples above).

type Item = T

Output item.

fn decode(self, value: &[u8]) -> T

Decode a byte-slice into the desired item.

Reads a sequence of IEEE754 single-precision (4 bytes) floating point numbers from the underlying reader. Read more

fn read_f32_into_unchecked<T>(&mut self, dst: &mut [f32]) -> Result<(), Error>
where T: ByteOrder,

👎Deprecated since 1.2.0: please use read_f32_into instead

DEPRECATED. Read more

fn read_f64_into<T>(&mut self, dst: &mut [f64]) -> Result<(), Error>
where T: ByteOrder,

Reads a sequence of IEEE754 double-precision (8 bytes) floating point numbers from the underlying reader. Read more

fn read_f64_into_unchecked<T>(&mut self, dst: &mut [f64]) -> Result<(), Error>
where T: ByteOrder,

👎Deprecated since 1.2.0: please use read_f64_into instead

DEPRECATED. Read more

impl<F, T> Replacer for F
where F: FnMut(&Captures<'_>) -> T, T: AsRef<[u8]>,

fn replace_append(&mut self, caps: &Captures<'_>, dst: &mut Vec<u8>)

Appends possibly empty data to dst to replace the current match. Read more

fn no_expansion<'r>(&'r mut self) -> Option<Cow<'r, [u8]>>

Return a fixed unchanging replacement byte string. Read more

fn by_ref<'r>(&'r mut self) -> ReplacerRef<'r, Self>

Returns a type that implements Replacer, but that borrows and wraps this Replacer. Read more

impl<F, T> Replacer for F
where F: FnMut(&Captures<'_>) -> T, T: AsRef<str>,

fn replace_append(&mut self, caps: &Captures<'_>, dst: &mut String)

Appends possibly empty data to dst to replace the current match. Read more

fn no_expansion<'r>(&'r mut self) -> Option<Cow<'r, str>>

Return a fixed unchanging replacement string. Read more

Consume self to return an equivalent value of T. Read more

impl<T, Request> ServiceExt<Request> for T
where T: Service<Request> + ?Sized,

fn ready(&mut self) -> Ready<'_, Self, Request>
where Self: Sized,

Yields a mutable reference to the service when it is ready to accept a request.

fn ready_and(&mut self) -> Ready<'_, Self, Request>
where Self: Sized,

👎Deprecated since 0.4.6: please use the ServiceExt::ready method instead

Convert the service into a Service + Clone + Send trait object. Read more

fn spawn<Fut>(&self, future: Fut) -> Result<(), SpawnError>
where Fut: Future<Output = ()> + Send + 'static,

Spawns a task that polls the given future with output () to completion. Read more

fn spawn_with_handle<Fut>( &self, future: Fut, ) -> Result<RemoteHandle<<Fut as Future>::Output>, SpawnError>
where Fut: Future + Send + 'static, <Fut as Future>::Output: Send,

Spawns a task that polls the given future to completion and returns a future that resolves to the spawned future’s output. Read more

Attempts to set self as the global default subscriber in the current scope, returning an error if one is already set. Read more

fn init(self)

Attempts to set self as the global default subscriber in the current scope, panicking if this fails. Read more

Calls .tap_deref_mut() only in debug builds, and is erased in release builds.

impl<T> ToHex for T
where T: AsRef<[u8]>,

fn encode_hex(&self) -> U
where U: FromIterator<char>,

Encode the hex strict representing self into the result. Lower case letters are used (e.g. f9b4ca)

fn encode_hex_upper(&self) -> U
where U: FromIterator<char>,

Encode the hex strict representing self into the result. Upper case letters are used (e.g. F9B4CA)

impl<T> ToOwned for T
where T: Clone,

type Owned = T

The resulting type after obtaining ownership.

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

Consume self and try to collect the results into C. Read more

impl<I, T, Bound> TryCollect<BoundedBTreeSet<T, Bound>> for I
where T: Ord, I: ExactSizeIterator<Item = T> + Iterator, Bound: Get<u32>,

type Error = &'static str

The error type that gets returned when a collection can’t be made from self.

fn try_collect( self, ) -> Result<BoundedBTreeSet<T, Bound>, >>::Error>

Consume self and try to collect the results into C. Read more

impl<I, T, Bound> TryCollect<BoundedVec<T, Bound>> for I
where I: ExactSizeIterator<Item = T> + Iterator, Bound: Get<u32>,

type Error = &'static str

The error type that gets returned when a collection can’t be made from self.

Performs the conversion.

impl<F, T, E> TryFuture for F
where F: Future<Output = Result<T, E>> + ?Sized,

type Ok = T

The type of successful values yielded by this future

type Error = E

The type of failures yielded by this future

fn try_poll( self: Pin<&mut F>, cx: &mut Context<'_>, ) -> Poll<<F as Future>::Output>

Poll this TryFuture as if it were a Future. Read more

type Error = >::Error

The type returned in the event of a conversion error.

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

impl<S, T, E> TryStream for S
where S: Stream<Item = Result<T, E>> + ?Sized,

type Ok = T

The type of successful values yielded by this future

type Error = E

The type of failures yielded by this future

fn try_poll_next( self: Pin<&mut S>, cx: &mut Context<'_>, ) -> Poll<Option<Result<<S as TryStream>::Ok, <S as TryStream>::Error>>>

Poll this TryStream as if it were a Stream. Read more

Returns an iterator over the string in Unicode Normalization Form KD (compatibility decomposition).

fn nfc(self) -> Recompositions ⓘ

An Iterator over the string in Unicode Normalization Form C (canonical decomposition followed by canonical composition).

fn nfkc(self) -> Recompositions ⓘ

An Iterator over the string in Unicode Normalization Form KC (compatibility decomposition followed by canonical composition).

fn cjk_compat_variants(self) -> Replacements ⓘ

A transformation which replaces CJK Compatibility Ideograph codepoints with normal forms using Standardized Variation Sequences. This is not part of the canonical or compatibility decomposition algorithms, but performing it before those algorithms produces normalized output which better preserves the intent of the original text. Read more

fn stream_safe(self) -> StreamSafe ⓘ

An Iterator over the string with Conjoining Grapheme Joiner characters inserted according to the Stream-Safe Text Process (UAX15-D4)

impl<T, S> UniqueSaturatedInto<T> for S
where T: Bounded, S: TryInto<T>,

fn unique_saturated_into(self) -> T

Consume self to return an equivalent value of T.

impl<V, T> VZip<V> for T
where V: MultiLane<T>,

fn vzip(self) -> V

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a [WithDispatch] wrapper. Read more

fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a [WithDispatch] wrapper. Read more