Rollup merge of #132233 - WaffleLapkin:box-module-split, r=workingjubilee

Split `boxed.rs` into a few modules

I wanted to add an impl for `Box<_>`, but was quickly discouraged by the 3K file. This splits off a couple bits, making it at least a bit more manageable.

r? ````@workingjubilee```` (I think you are not bothered by refactorings like this?)
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Jubilee 2024-10-29 03:11:42 -07:00 committed by GitHub
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use core::any::Any;
use core::error::Error;
use core::mem;
use core::pin::Pin;
#[cfg(not(no_global_oom_handling))]
use core::{fmt, ptr};
use crate::alloc::Allocator;
#[cfg(not(no_global_oom_handling))]
use crate::borrow::Cow;
use crate::boxed::Box;
#[cfg(not(no_global_oom_handling))]
use crate::raw_vec::RawVec;
#[cfg(not(no_global_oom_handling))]
use crate::str::from_boxed_utf8_unchecked;
#[cfg(not(no_global_oom_handling))]
use crate::string::String;
#[cfg(not(no_global_oom_handling))]
use crate::vec::Vec;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "from_for_ptrs", since = "1.6.0")]
impl<T> From<T> for Box<T> {
/// Converts a `T` into a `Box<T>`
///
/// The conversion allocates on the heap and moves `t`
/// from the stack into it.
///
/// # Examples
///
/// ```rust
/// let x = 5;
/// let boxed = Box::new(5);
///
/// assert_eq!(Box::from(x), boxed);
/// ```
fn from(t: T) -> Self {
Box::new(t)
}
}
#[stable(feature = "pin", since = "1.33.0")]
impl<T: ?Sized, A: Allocator> From<Box<T, A>> for 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 [`Box::into_pin`].
///
/// Constructing and pinning a `Box` with <code><Pin<Box\<T>>>::from([Box::new]\(x))</code>
/// can also be written more concisely using <code>[Box::pin]\(x)</code>.
/// 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`].
fn from(boxed: Box<T, A>) -> Self {
Box::into_pin(boxed)
}
}
/// Specialization trait used for `From<&[T]>`.
#[cfg(not(no_global_oom_handling))]
trait BoxFromSlice<T> {
fn from_slice(slice: &[T]) -> Self;
}
#[cfg(not(no_global_oom_handling))]
impl<T: Clone> BoxFromSlice<T> for Box<[T]> {
#[inline]
default fn from_slice(slice: &[T]) -> Self {
slice.to_vec().into_boxed_slice()
}
}
#[cfg(not(no_global_oom_handling))]
impl<T: Copy> BoxFromSlice<T> for Box<[T]> {
#[inline]
fn from_slice(slice: &[T]) -> Self {
let len = slice.len();
let buf = RawVec::with_capacity(len);
unsafe {
ptr::copy_nonoverlapping(slice.as_ptr(), buf.ptr(), len);
buf.into_box(slice.len()).assume_init()
}
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "box_from_slice", since = "1.17.0")]
impl<T: Clone> From<&[T]> for 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
/// ```rust
/// // 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:?}");
/// ```
#[inline]
fn from(slice: &[T]) -> Box<[T]> {
<Self as BoxFromSlice<T>>::from_slice(slice)
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "box_from_cow", since = "1.45.0")]
impl<T: Clone> From<Cow<'_, [T]>> for Box<[T]> {
/// Converts a `Cow<'_, [T]>` into a `Box<[T]>`
///
/// When `cow` is the `Cow::Borrowed` variant, this
/// conversion allocates on the heap and copies the
/// underlying slice. Otherwise, it will try to reuse the owned
/// `Vec`'s allocation.
#[inline]
fn from(cow: Cow<'_, [T]>) -> Box<[T]> {
match cow {
Cow::Borrowed(slice) => Box::from(slice),
Cow::Owned(slice) => Box::from(slice),
}
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "box_from_slice", since = "1.17.0")]
impl From<&str> for Box<str> {
/// Converts a `&str` into a `Box<str>`
///
/// This conversion allocates on the heap
/// and performs a copy of `s`.
///
/// # Examples
///
/// ```rust
/// let boxed: Box<str> = Box::from("hello");
/// println!("{boxed}");
/// ```
#[inline]
fn from(s: &str) -> Box<str> {
unsafe { from_boxed_utf8_unchecked(Box::from(s.as_bytes())) }
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "box_from_cow", since = "1.45.0")]
impl From<Cow<'_, str>> for 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
///
/// ```rust
/// use std::borrow::Cow;
///
/// let unboxed = Cow::Borrowed("hello");
/// let boxed: Box<str> = Box::from(unboxed);
/// println!("{boxed}");
/// ```
///
/// ```rust
/// # use std::borrow::Cow;
/// let unboxed = Cow::Owned("hello".to_string());
/// let boxed: Box<str> = Box::from(unboxed);
/// println!("{boxed}");
/// ```
#[inline]
fn from(cow: Cow<'_, str>) -> Box<str> {
match cow {
Cow::Borrowed(s) => Box::from(s),
Cow::Owned(s) => Box::from(s),
}
}
}
#[stable(feature = "boxed_str_conv", since = "1.19.0")]
impl<A: Allocator> From<Box<str, A>> for Box<[u8], A> {
/// Converts a `Box<str>` into a `Box<[u8]>`
///
/// This conversion does not allocate on the heap and happens in place.
///
/// # Examples
/// ```rust
/// // 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);
/// ```
#[inline]
fn from(s: Box<str, A>) -> Self {
let (raw, alloc) = Box::into_raw_with_allocator(s);
unsafe { Box::from_raw_in(raw as *mut [u8], alloc) }
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "box_from_array", since = "1.45.0")]
impl<T, const N: usize> From<[T; N]> for Box<[T]> {
/// Converts a `[T; N]` into a `Box<[T]>`
///
/// This conversion moves the array to newly heap-allocated memory.
///
/// # Examples
///
/// ```rust
/// let boxed: Box<[u8]> = Box::from([4, 2]);
/// println!("{boxed:?}");
/// ```
fn from(array: [T; N]) -> Box<[T]> {
Box::new(array)
}
}
/// Casts a boxed slice to a boxed array.
///
/// # Safety
///
/// `boxed_slice.len()` must be exactly `N`.
unsafe fn boxed_slice_as_array_unchecked<T, A: Allocator, const N: usize>(
boxed_slice: Box<[T], A>,
) -> Box<[T; N], A> {
debug_assert_eq!(boxed_slice.len(), N);
let (ptr, alloc) = Box::into_raw_with_allocator(boxed_slice);
// SAFETY: Pointer and allocator came from an existing box,
// and our safety condition requires that the length is exactly `N`
unsafe { Box::from_raw_in(ptr as *mut [T; N], alloc) }
}
#[stable(feature = "boxed_slice_try_from", since = "1.43.0")]
impl<T, const N: usize> TryFrom<Box<[T]>> for Box<[T; N]> {
type Error = Box<[T]>;
/// Attempts to convert a `Box<[T]>` into a `Box<[T; N]>`.
///
/// The conversion occurs in-place and does not require a
/// new memory allocation.
///
/// # Errors
///
/// Returns the old `Box<[T]>` in the `Err` variant if
/// `boxed_slice.len()` does not equal `N`.
fn try_from(boxed_slice: Box<[T]>) -> Result<Self, Self::Error> {
if boxed_slice.len() == N {
Ok(unsafe { boxed_slice_as_array_unchecked(boxed_slice) })
} else {
Err(boxed_slice)
}
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_array_try_from_vec", since = "1.66.0")]
impl<T, const N: usize> TryFrom<Vec<T>> for Box<[T; N]> {
type Error = Vec<T>;
/// 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);
/// ```
fn try_from(vec: Vec<T>) -> Result<Self, Self::Error> {
if vec.len() == N {
let boxed_slice = vec.into_boxed_slice();
Ok(unsafe { boxed_slice_as_array_unchecked(boxed_slice) })
} else {
Err(vec)
}
}
}
impl<A: Allocator> Box<dyn Any, A> {
/// 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));
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
}
/// 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*.
///
/// [`downcast`]: Self::downcast
#[inline]
#[unstable(feature = "downcast_unchecked", issue = "90850")]
pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
debug_assert!(self.is::<T>());
unsafe {
let (raw, alloc): (*mut dyn Any, _) = Box::into_raw_with_allocator(self);
Box::from_raw_in(raw as *mut T, alloc)
}
}
}
impl<A: Allocator> Box<dyn Any + Send, A> {
/// 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));
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
}
/// 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*.
///
/// [`downcast`]: Self::downcast
#[inline]
#[unstable(feature = "downcast_unchecked", issue = "90850")]
pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
debug_assert!(self.is::<T>());
unsafe {
let (raw, alloc): (*mut (dyn Any + Send), _) = Box::into_raw_with_allocator(self);
Box::from_raw_in(raw as *mut T, alloc)
}
}
}
impl<A: Allocator> Box<dyn Any + Send + Sync, A> {
/// 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));
/// ```
#[inline]
#[stable(feature = "box_send_sync_any_downcast", since = "1.51.0")]
pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
}
/// 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*.
///
/// [`downcast`]: Self::downcast
#[inline]
#[unstable(feature = "downcast_unchecked", issue = "90850")]
pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
debug_assert!(self.is::<T>());
unsafe {
let (raw, alloc): (*mut (dyn Any + Send + Sync), _) =
Box::into_raw_with_allocator(self);
Box::from_raw_in(raw as *mut T, alloc)
}
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a, E: Error + 'a> From<E> for 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))
/// ```
fn from(err: E) -> Box<dyn Error + 'a> {
Box::new(err)
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> {
/// Converts a type of [`Error`] + [`Send`] + [`Sync`] into a box of
/// dyn [`Error`] + [`Send`] + [`Sync`].
///
/// # 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 {}
///
/// unsafe impl Send for AnError {}
///
/// unsafe impl Sync for AnError {}
///
/// let an_error = AnError;
/// assert!(0 == mem::size_of_val(&an_error));
/// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
/// assert!(
/// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
/// ```
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a> {
Box::new(err)
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a> From<String> for Box<dyn Error + Send + Sync + 'a> {
/// Converts a [`String`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
///
/// # Examples
///
/// ```
/// use std::error::Error;
/// use std::mem;
///
/// let a_string_error = "a string error".to_string();
/// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
/// assert!(
/// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
/// ```
#[inline]
fn from(err: String) -> Box<dyn Error + Send + Sync + 'a> {
struct StringError(String);
impl Error for StringError {
#[allow(deprecated)]
fn description(&self) -> &str {
&self.0
}
}
impl fmt::Display for StringError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&self.0, f)
}
}
// Purposefully skip printing "StringError(..)"
impl fmt::Debug for StringError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.0, f)
}
}
Box::new(StringError(err))
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "string_box_error", since = "1.6.0")]
impl<'a> From<String> for Box<dyn Error + 'a> {
/// Converts a [`String`] into a box of dyn [`Error`].
///
/// # Examples
///
/// ```
/// use std::error::Error;
/// use std::mem;
///
/// let a_string_error = "a string error".to_string();
/// let a_boxed_error = Box::<dyn Error>::from(a_string_error);
/// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
/// ```
fn from(str_err: String) -> Box<dyn Error + 'a> {
let err1: Box<dyn Error + Send + Sync> = From::from(str_err);
let err2: Box<dyn Error> = err1;
err2
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
/// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
///
/// [`str`]: prim@str
///
/// # Examples
///
/// ```
/// use std::error::Error;
/// use std::mem;
///
/// let a_str_error = "a str error";
/// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
/// assert!(
/// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
/// ```
#[inline]
fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a> {
From::from(String::from(err))
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "string_box_error", since = "1.6.0")]
impl<'a> From<&str> for Box<dyn Error + 'a> {
/// Converts a [`str`] into a box of dyn [`Error`].
///
/// [`str`]: prim@str
///
/// # Examples
///
/// ```
/// use std::error::Error;
/// use std::mem;
///
/// let a_str_error = "a str error";
/// let a_boxed_error = Box::<dyn Error>::from(a_str_error);
/// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
/// ```
fn from(err: &str) -> Box<dyn Error + 'a> {
From::from(String::from(err))
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "cow_box_error", since = "1.22.0")]
impl<'a, 'b> From<Cow<'b, str>> for 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))
/// ```
fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a> {
From::from(String::from(err))
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "cow_box_error", since = "1.22.0")]
impl<'a, 'b> From<Cow<'b, str>> for 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))
/// ```
fn from(err: Cow<'b, str>) -> Box<dyn Error + 'a> {
From::from(String::from(err))
}
}
impl dyn Error {
/// Attempts to downcast the box to a concrete type.
#[inline]
#[stable(feature = "error_downcast", since = "1.3.0")]
#[rustc_allow_incoherent_impl]
pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error>> {
if self.is::<T>() {
unsafe {
let raw: *mut dyn Error = Box::into_raw(self);
Ok(Box::from_raw(raw as *mut T))
}
} else {
Err(self)
}
}
}
impl dyn Error + Send {
/// Attempts to downcast the box to a concrete type.
#[inline]
#[stable(feature = "error_downcast", since = "1.3.0")]
#[rustc_allow_incoherent_impl]
pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error + Send>> {
let err: Box<dyn Error> = self;
<dyn Error>::downcast(err).map_err(|s| unsafe {
// Reapply the `Send` marker.
mem::transmute::<Box<dyn Error>, Box<dyn Error + Send>>(s)
})
}
}
impl dyn Error + Send + Sync {
/// Attempts to downcast the box to a concrete type.
#[inline]
#[stable(feature = "error_downcast", since = "1.3.0")]
#[rustc_allow_incoherent_impl]
pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
let err: Box<dyn Error> = self;
<dyn Error>::downcast(err).map_err(|s| unsafe {
// Reapply the `Send + Sync` markers.
mem::transmute::<Box<dyn Error>, Box<dyn Error + Send + Sync>>(s)
})
}
}

View File

@ -0,0 +1,194 @@
use core::async_iter::AsyncIterator;
use core::iter::FusedIterator;
use core::pin::Pin;
use core::slice;
use core::task::{Context, Poll};
use crate::alloc::Allocator;
#[cfg(not(no_global_oom_handling))]
use crate::borrow::Cow;
use crate::boxed::Box;
#[cfg(not(no_global_oom_handling))]
use crate::string::String;
use crate::vec;
#[cfg(not(no_global_oom_handling))]
use crate::vec::Vec;
#[stable(feature = "rust1", since = "1.0.0")]
impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> {
type Item = I::Item;
fn next(&mut self) -> Option<I::Item> {
(**self).next()
}
fn size_hint(&self) -> (usize, Option<usize>) {
(**self).size_hint()
}
fn nth(&mut self, n: usize) -> Option<I::Item> {
(**self).nth(n)
}
fn last(self) -> Option<I::Item> {
BoxIter::last(self)
}
}
trait BoxIter {
type Item;
fn last(self) -> Option<Self::Item>;
}
impl<I: Iterator + ?Sized, A: Allocator> BoxIter for Box<I, A> {
type Item = I::Item;
default fn last(self) -> Option<I::Item> {
#[inline]
fn some<T>(_: Option<T>, x: T) -> Option<T> {
Some(x)
}
self.fold(None, some)
}
}
/// Specialization for sized `I`s that uses `I`s implementation of `last()`
/// instead of the default.
#[stable(feature = "rust1", since = "1.0.0")]
impl<I: Iterator, A: Allocator> BoxIter for Box<I, A> {
fn last(self) -> Option<I::Item> {
(*self).last()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<I: DoubleEndedIterator + ?Sized, A: Allocator> DoubleEndedIterator for Box<I, A> {
fn next_back(&mut self) -> Option<I::Item> {
(**self).next_back()
}
fn nth_back(&mut self, n: usize) -> Option<I::Item> {
(**self).nth_back(n)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<I: ExactSizeIterator + ?Sized, A: Allocator> ExactSizeIterator for Box<I, A> {
fn len(&self) -> usize {
(**self).len()
}
fn is_empty(&self) -> bool {
(**self).is_empty()
}
}
#[stable(feature = "fused", since = "1.26.0")]
impl<I: FusedIterator + ?Sized, A: Allocator> FusedIterator for Box<I, A> {}
#[unstable(feature = "async_iterator", issue = "79024")]
impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S> {
type Item = S::Item;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
Pin::new(&mut **self).poll_next(cx)
}
fn size_hint(&self) -> (usize, Option<usize>) {
(**self).size_hint()
}
}
/// This implementation is required to make sure that the `Box<[I]>: IntoIterator`
/// implementation doesn't overlap with `IntoIterator for T where T: Iterator` blanket.
#[stable(feature = "boxed_slice_into_iter", since = "1.80.0")]
impl<I, A: Allocator> !Iterator for Box<[I], A> {}
/// This implementation is required to make sure that the `&Box<[I]>: IntoIterator`
/// implementation doesn't overlap with `IntoIterator for T where T: Iterator` blanket.
#[stable(feature = "boxed_slice_into_iter", since = "1.80.0")]
impl<'a, I, A: Allocator> !Iterator for &'a Box<[I], A> {}
/// This implementation is required to make sure that the `&mut Box<[I]>: IntoIterator`
/// implementation doesn't overlap with `IntoIterator for T where T: Iterator` blanket.
#[stable(feature = "boxed_slice_into_iter", since = "1.80.0")]
impl<'a, I, A: Allocator> !Iterator for &'a mut Box<[I], A> {}
// Note: the `#[rustc_skip_during_method_dispatch(boxed_slice)]` on `trait IntoIterator`
// hides this implementation from explicit `.into_iter()` calls on editions < 2024,
// so those calls will still resolve to the slice implementation, by reference.
#[stable(feature = "boxed_slice_into_iter", since = "1.80.0")]
impl<I, A: Allocator> IntoIterator for Box<[I], A> {
type IntoIter = vec::IntoIter<I, A>;
type Item = I;
fn into_iter(self) -> vec::IntoIter<I, A> {
self.into_vec().into_iter()
}
}
#[stable(feature = "boxed_slice_into_iter", since = "1.80.0")]
impl<'a, I, A: Allocator> IntoIterator for &'a Box<[I], A> {
type IntoIter = slice::Iter<'a, I>;
type Item = &'a I;
fn into_iter(self) -> slice::Iter<'a, I> {
self.iter()
}
}
#[stable(feature = "boxed_slice_into_iter", since = "1.80.0")]
impl<'a, I, A: Allocator> IntoIterator for &'a mut Box<[I], A> {
type IntoIter = slice::IterMut<'a, I>;
type Item = &'a mut I;
fn into_iter(self) -> slice::IterMut<'a, I> {
self.iter_mut()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_slice_from_iter", since = "1.32.0")]
impl<I> FromIterator<I> for Box<[I]> {
fn from_iter<T: IntoIterator<Item = I>>(iter: T) -> Self {
iter.into_iter().collect::<Vec<_>>().into_boxed_slice()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_str_from_iter", since = "1.80.0")]
impl FromIterator<char> for Box<str> {
fn from_iter<T: IntoIterator<Item = char>>(iter: T) -> Self {
String::from_iter(iter).into_boxed_str()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_str_from_iter", since = "1.80.0")]
impl<'a> FromIterator<&'a char> for Box<str> {
fn from_iter<T: IntoIterator<Item = &'a char>>(iter: T) -> Self {
String::from_iter(iter).into_boxed_str()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_str_from_iter", since = "1.80.0")]
impl<'a> FromIterator<&'a str> for Box<str> {
fn from_iter<T: IntoIterator<Item = &'a str>>(iter: T) -> Self {
String::from_iter(iter).into_boxed_str()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_str_from_iter", since = "1.80.0")]
impl FromIterator<String> for Box<str> {
fn from_iter<T: IntoIterator<Item = String>>(iter: T) -> Self {
String::from_iter(iter).into_boxed_str()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_str_from_iter", since = "1.80.0")]
impl<A: Allocator> FromIterator<Box<str, A>> for Box<str> {
fn from_iter<T: IntoIterator<Item = Box<str, A>>>(iter: T) -> Self {
String::from_iter(iter).into_boxed_str()
}
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "boxed_str_from_iter", since = "1.80.0")]
impl<'a> FromIterator<Cow<'a, str>> for Box<str> {
fn from_iter<T: IntoIterator<Item = Cow<'a, str>>>(iter: T) -> Self {
String::from_iter(iter).into_boxed_str()
}
}

View File

@ -23,7 +23,7 @@ note: inside `<CoroutineIteratorAdapter<{static coroutine@tests/fail/coroutine-p
| |
LL | match me.resume(()) { LL | match me.resume(()) {
| ^^^^^^^^^^^^^ | ^^^^^^^^^^^^^
= note: inside `<std::boxed::Box<CoroutineIteratorAdapter<{static coroutine@tests/fail/coroutine-pinned-moved.rs:LL:CC}>> as std::iter::Iterator>::next` at RUSTLIB/alloc/src/boxed.rs:LL:CC = note: inside `std::boxed::iter::<impl std::iter::Iterator for std::boxed::Box<CoroutineIteratorAdapter<{static coroutine@tests/fail/coroutine-pinned-moved.rs:LL:CC}>>>::next` at RUSTLIB/alloc/src/boxed/iter.rs:LL:CC
note: inside `main` note: inside `main`
--> tests/fail/coroutine-pinned-moved.rs:LL:CC --> tests/fail/coroutine-pinned-moved.rs:LL:CC
| |