Split boxed.rs into a few modules
+ some minor style changes
This commit is contained in:
Maybe Lapkin
Jubilee Young
parent
17f8215394
commit
b2f335ea99
File diff suppressed because it is too large
Load Diff
747
library/alloc/src/boxed/convert.rs
Normal file
747
library/alloc/src/boxed/convert.rs
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@ -0,0 +1,747 @@
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use core::any::Any;
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use core::error::Error;
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use core::mem;
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use core::pin::Pin;
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#[cfg(not(no_global_oom_handling))]
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use core::{fmt, ptr};
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use crate::alloc::Allocator;
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#[cfg(not(no_global_oom_handling))]
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use crate::borrow::Cow;
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use crate::boxed::Box;
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#[cfg(not(no_global_oom_handling))]
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use crate::raw_vec::RawVec;
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#[cfg(not(no_global_oom_handling))]
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use crate::str::from_boxed_utf8_unchecked;
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#[cfg(not(no_global_oom_handling))]
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use crate::string::String;
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#[cfg(not(no_global_oom_handling))]
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use crate::vec::Vec;
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "from_for_ptrs", since = "1.6.0")]
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impl<T> From<T> for Box<T> {
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/// Converts a `T` into a `Box<T>`
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///
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/// The conversion allocates on the heap and moves `t`
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/// from the stack into it.
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///
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/// # Examples
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///
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/// ```rust
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/// let x = 5;
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/// let boxed = Box::new(5);
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///
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/// assert_eq!(Box::from(x), boxed);
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/// ```
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fn from(t: T) -> Self {
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Box::new(t)
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}
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}
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#[stable(feature = "pin", since = "1.33.0")]
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impl<T: ?Sized, A: Allocator> From<Box<T, A>> for Pin<Box<T, A>>
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where
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A: 'static,
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{
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/// Converts a `Box<T>` into a `Pin<Box<T>>`. If `T` does not implement [`Unpin`], then
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/// `*boxed` will be pinned in memory and unable to be moved.
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///
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/// This conversion does not allocate on the heap and happens in place.
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///
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/// This is also available via [`Box::into_pin`].
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///
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/// Constructing and pinning a `Box` with <code><Pin<Box\<T>>>::from([Box::new]\(x))</code>
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/// can also be written more concisely using <code>[Box::pin]\(x)</code>.
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/// This `From` implementation is useful if you already have a `Box<T>`, or you are
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/// constructing a (pinned) `Box` in a different way than with [`Box::new`].
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fn from(boxed: Box<T, A>) -> Self {
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Box::into_pin(boxed)
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}
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}
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/// Specialization trait used for `From<&[T]>`.
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#[cfg(not(no_global_oom_handling))]
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trait BoxFromSlice<T> {
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fn from_slice(slice: &[T]) -> Self;
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}
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#[cfg(not(no_global_oom_handling))]
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impl<T: Clone> BoxFromSlice<T> for Box<[T]> {
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#[inline]
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default fn from_slice(slice: &[T]) -> Self {
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slice.to_vec().into_boxed_slice()
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}
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}
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#[cfg(not(no_global_oom_handling))]
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impl<T: Copy> BoxFromSlice<T> for Box<[T]> {
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#[inline]
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fn from_slice(slice: &[T]) -> Self {
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let len = slice.len();
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let buf = RawVec::with_capacity(len);
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unsafe {
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ptr::copy_nonoverlapping(slice.as_ptr(), buf.ptr(), len);
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buf.into_box(slice.len()).assume_init()
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}
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "box_from_slice", since = "1.17.0")]
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impl<T: Clone> From<&[T]> for Box<[T]> {
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/// Converts a `&[T]` into a `Box<[T]>`
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///
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/// This conversion allocates on the heap
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/// and performs a copy of `slice` and its contents.
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///
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/// # Examples
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/// ```rust
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/// // create a &[u8] which will be used to create a Box<[u8]>
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/// let slice: &[u8] = &[104, 101, 108, 108, 111];
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/// let boxed_slice: Box<[u8]> = Box::from(slice);
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///
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/// println!("{boxed_slice:?}");
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/// ```
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#[inline]
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fn from(slice: &[T]) -> Box<[T]> {
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<Self as BoxFromSlice<T>>::from_slice(slice)
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "box_from_cow", since = "1.45.0")]
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impl<T: Clone> From<Cow<'_, [T]>> for Box<[T]> {
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/// Converts a `Cow<'_, [T]>` into a `Box<[T]>`
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///
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/// When `cow` is the `Cow::Borrowed` variant, this
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/// conversion allocates on the heap and copies the
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/// underlying slice. Otherwise, it will try to reuse the owned
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/// `Vec`'s allocation.
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#[inline]
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fn from(cow: Cow<'_, [T]>) -> Box<[T]> {
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match cow {
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Cow::Borrowed(slice) => Box::from(slice),
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Cow::Owned(slice) => Box::from(slice),
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}
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "box_from_slice", since = "1.17.0")]
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impl From<&str> for Box<str> {
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/// Converts a `&str` into a `Box<str>`
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///
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/// This conversion allocates on the heap
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/// and performs a copy of `s`.
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///
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/// # Examples
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///
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/// ```rust
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/// let boxed: Box<str> = Box::from("hello");
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/// println!("{boxed}");
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/// ```
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#[inline]
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fn from(s: &str) -> Box<str> {
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unsafe { from_boxed_utf8_unchecked(Box::from(s.as_bytes())) }
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "box_from_cow", since = "1.45.0")]
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impl From<Cow<'_, str>> for Box<str> {
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/// Converts a `Cow<'_, str>` into a `Box<str>`
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///
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/// When `cow` is the `Cow::Borrowed` variant, this
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/// conversion allocates on the heap and copies the
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/// underlying `str`. Otherwise, it will try to reuse the owned
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/// `String`'s allocation.
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///
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/// # Examples
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///
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/// ```rust
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/// use std::borrow::Cow;
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///
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/// let unboxed = Cow::Borrowed("hello");
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/// let boxed: Box<str> = Box::from(unboxed);
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/// println!("{boxed}");
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/// ```
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///
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/// ```rust
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/// # use std::borrow::Cow;
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/// let unboxed = Cow::Owned("hello".to_string());
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/// let boxed: Box<str> = Box::from(unboxed);
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/// println!("{boxed}");
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/// ```
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#[inline]
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fn from(cow: Cow<'_, str>) -> Box<str> {
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match cow {
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Cow::Borrowed(s) => Box::from(s),
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Cow::Owned(s) => Box::from(s),
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}
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}
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}
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#[stable(feature = "boxed_str_conv", since = "1.19.0")]
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impl<A: Allocator> From<Box<str, A>> for Box<[u8], A> {
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/// Converts a `Box<str>` into a `Box<[u8]>`
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///
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/// This conversion does not allocate on the heap and happens in place.
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///
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/// # Examples
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/// ```rust
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/// // create a Box<str> which will be used to create a Box<[u8]>
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/// let boxed: Box<str> = Box::from("hello");
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/// let boxed_str: Box<[u8]> = Box::from(boxed);
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///
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/// // create a &[u8] which will be used to create a Box<[u8]>
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/// let slice: &[u8] = &[104, 101, 108, 108, 111];
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/// let boxed_slice = Box::from(slice);
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///
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/// assert_eq!(boxed_slice, boxed_str);
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/// ```
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#[inline]
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fn from(s: Box<str, A>) -> Self {
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let (raw, alloc) = Box::into_raw_with_allocator(s);
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unsafe { Box::from_raw_in(raw as *mut [u8], alloc) }
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "box_from_array", since = "1.45.0")]
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impl<T, const N: usize> From<[T; N]> for Box<[T]> {
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/// Converts a `[T; N]` into a `Box<[T]>`
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///
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/// This conversion moves the array to newly heap-allocated memory.
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///
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/// # Examples
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///
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/// ```rust
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/// let boxed: Box<[u8]> = Box::from([4, 2]);
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/// println!("{boxed:?}");
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/// ```
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fn from(array: [T; N]) -> Box<[T]> {
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Box::new(array)
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}
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}
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/// Casts a boxed slice to a boxed array.
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///
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/// # Safety
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///
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/// `boxed_slice.len()` must be exactly `N`.
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unsafe fn boxed_slice_as_array_unchecked<T, A: Allocator, const N: usize>(
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boxed_slice: Box<[T], A>,
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) -> Box<[T; N], A> {
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debug_assert_eq!(boxed_slice.len(), N);
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let (ptr, alloc) = Box::into_raw_with_allocator(boxed_slice);
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// SAFETY: Pointer and allocator came from an existing box,
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// and our safety condition requires that the length is exactly `N`
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unsafe { Box::from_raw_in(ptr as *mut [T; N], alloc) }
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}
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#[stable(feature = "boxed_slice_try_from", since = "1.43.0")]
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impl<T, const N: usize> TryFrom<Box<[T]>> for Box<[T; N]> {
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type Error = Box<[T]>;
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/// Attempts to convert a `Box<[T]>` into a `Box<[T; N]>`.
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///
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/// The conversion occurs in-place and does not require a
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/// new memory allocation.
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///
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/// # Errors
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///
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/// Returns the old `Box<[T]>` in the `Err` variant if
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/// `boxed_slice.len()` does not equal `N`.
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fn try_from(boxed_slice: Box<[T]>) -> Result<Self, Self::Error> {
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if boxed_slice.len() == N {
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Ok(unsafe { boxed_slice_as_array_unchecked(boxed_slice) })
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} else {
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Err(boxed_slice)
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}
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}
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}
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#[cfg(not(no_global_oom_handling))]
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#[stable(feature = "boxed_array_try_from_vec", since = "1.66.0")]
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impl<T, const N: usize> TryFrom<Vec<T>> for Box<[T; N]> {
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type Error = Vec<T>;
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/// Attempts to convert a `Vec<T>` into a `Box<[T; N]>`.
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///
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/// Like [`Vec::into_boxed_slice`], this is in-place if `vec.capacity() == N`,
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/// but will require a reallocation otherwise.
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///
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/// # Errors
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///
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/// Returns the original `Vec<T>` in the `Err` variant if
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/// `boxed_slice.len()` does not equal `N`.
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///
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/// # Examples
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///
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/// This can be used with [`vec!`] to create an array on the heap:
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///
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/// ```
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/// let state: Box<[f32; 100]> = vec![1.0; 100].try_into().unwrap();
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/// assert_eq!(state.len(), 100);
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/// ```
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fn try_from(vec: Vec<T>) -> Result<Self, Self::Error> {
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if vec.len() == N {
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let boxed_slice = vec.into_boxed_slice();
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Ok(unsafe { boxed_slice_as_array_unchecked(boxed_slice) })
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} else {
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Err(vec)
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}
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}
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}
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impl<A: Allocator> Box<dyn Any, A> {
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/// Attempts to downcast the box to a concrete type.
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///
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/// # Examples
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///
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/// ```
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/// use std::any::Any;
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///
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/// fn print_if_string(value: Box<dyn Any>) {
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/// if let Ok(string) = value.downcast::<String>() {
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/// println!("String ({}): {}", string.len(), string);
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/// }
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/// }
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///
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/// let my_string = "Hello World".to_string();
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/// print_if_string(Box::new(my_string));
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/// print_if_string(Box::new(0i8));
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
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if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
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}
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/// Downcasts the box to a concrete type.
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///
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/// For a safe alternative see [`downcast`].
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///
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/// # Examples
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///
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/// ```
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/// #![feature(downcast_unchecked)]
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///
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/// use std::any::Any;
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///
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/// let x: Box<dyn Any> = Box::new(1_usize);
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///
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/// unsafe {
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/// assert_eq!(*x.downcast_unchecked::<usize>(), 1);
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/// }
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/// ```
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///
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/// # Safety
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///
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/// The contained value must be of type `T`. Calling this method
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/// with the incorrect type is *undefined behavior*.
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///
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/// [`downcast`]: Self::downcast
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#[inline]
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#[unstable(feature = "downcast_unchecked", issue = "90850")]
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pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
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debug_assert!(self.is::<T>());
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unsafe {
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let (raw, alloc): (*mut dyn Any, _) = Box::into_raw_with_allocator(self);
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Box::from_raw_in(raw as *mut T, alloc)
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}
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}
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}
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impl<A: Allocator> Box<dyn Any + Send, A> {
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/// Attempts to downcast the box to a concrete type.
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///
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/// # Examples
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///
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/// ```
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/// use std::any::Any;
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///
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/// fn print_if_string(value: Box<dyn Any + Send>) {
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/// if let Ok(string) = value.downcast::<String>() {
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/// println!("String ({}): {}", string.len(), string);
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/// }
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/// }
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///
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/// let my_string = "Hello World".to_string();
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/// print_if_string(Box::new(my_string));
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/// print_if_string(Box::new(0i8));
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
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if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
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}
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/// Downcasts the box to a concrete type.
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///
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/// For a safe alternative see [`downcast`].
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///
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/// # Examples
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///
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/// ```
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/// #![feature(downcast_unchecked)]
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///
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/// use std::any::Any;
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///
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/// let x: Box<dyn Any + Send> = Box::new(1_usize);
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///
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/// unsafe {
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/// assert_eq!(*x.downcast_unchecked::<usize>(), 1);
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/// }
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/// ```
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///
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/// # Safety
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///
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/// The contained value must be of type `T`. Calling this method
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/// with the incorrect type is *undefined behavior*.
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///
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/// [`downcast`]: Self::downcast
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#[inline]
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#[unstable(feature = "downcast_unchecked", issue = "90850")]
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pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
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debug_assert!(self.is::<T>());
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unsafe {
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let (raw, alloc): (*mut (dyn Any + Send), _) = Box::into_raw_with_allocator(self);
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Box::from_raw_in(raw as *mut T, alloc)
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}
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}
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}
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impl<A: Allocator> Box<dyn Any + Send + Sync, A> {
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/// Attempts to downcast the box to a concrete type.
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///
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/// # Examples
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///
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/// ```
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/// use std::any::Any;
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///
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/// fn print_if_string(value: Box<dyn Any + Send + Sync>) {
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/// if let Ok(string) = value.downcast::<String>() {
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/// println!("String ({}): {}", string.len(), string);
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/// }
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/// }
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///
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/// let my_string = "Hello World".to_string();
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/// print_if_string(Box::new(my_string));
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/// print_if_string(Box::new(0i8));
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/// ```
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#[inline]
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#[stable(feature = "box_send_sync_any_downcast", since = "1.51.0")]
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pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
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if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
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}
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/// Downcasts the box to a concrete type.
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///
|
||||
/// 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)
|
||||
})
|
||||
}
|
||||
}
|
||||
194
library/alloc/src/boxed/iter.rs
Normal file
194
library/alloc/src/boxed/iter.rs
Normal 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()
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user