diff --git a/std/src/ffi/os_str.rs b/std/src/ffi/os_str.rs index a501bcc98cf38..f68ea3c562a5e 100644 --- a/std/src/ffi/os_str.rs +++ b/std/src/ffi/os_str.rs @@ -3,10 +3,13 @@ #[cfg(test)] mod tests; +use core::clone::CloneToUninit; + use crate::borrow::{Borrow, Cow}; use crate::collections::TryReserveError; use crate::hash::{Hash, Hasher}; use crate::ops::{self, Range}; +use crate::ptr::addr_of_mut; use crate::rc::Rc; use crate::str::FromStr; use crate::sync::Arc; @@ -1261,6 +1264,15 @@ impl Clone for Box { } } +#[unstable(feature = "clone_to_uninit", issue = "126799")] +unsafe impl CloneToUninit for OsStr { + #[cfg_attr(debug_assertions, track_caller)] + unsafe fn clone_to_uninit(&self, dst: *mut Self) { + // SAFETY: we're just a wrapper around a platform-specific Slice + unsafe { self.inner.clone_to_uninit(addr_of_mut!((*dst).inner)) } + } +} + #[stable(feature = "shared_from_slice2", since = "1.24.0")] impl From for Arc { /// Converts an [`OsString`] into an [Arc]<[OsStr]> by moving the [`OsString`] diff --git a/std/src/ffi/os_str/tests.rs b/std/src/ffi/os_str/tests.rs index 5b39b9e34d8c7..67147934b4db3 100644 --- a/std/src/ffi/os_str/tests.rs +++ b/std/src/ffi/os_str/tests.rs @@ -1,4 +1,6 @@ use super::*; +use crate::mem::MaybeUninit; +use crate::ptr; #[test] fn test_os_string_with_capacity() { @@ -286,3 +288,18 @@ fn slice_surrogate_edge() { assert_eq!(post_crab.slice_encoded_bytes(..4), "🦀"); assert_eq!(post_crab.slice_encoded_bytes(4..), surrogate); } + +#[test] +fn clone_to_uninit() { + let a = OsStr::new("hello.txt"); + + let mut storage = vec![MaybeUninit::::uninit(); size_of_val::(a)]; + unsafe { a.clone_to_uninit(ptr::from_mut::<[_]>(storage.as_mut_slice()) as *mut OsStr) }; + assert_eq!(a.as_encoded_bytes(), unsafe { MaybeUninit::slice_assume_init_ref(&storage) }); + + let mut b: Box = OsStr::new("world.exe").into(); + assert_eq!(size_of_val::(a), size_of_val::(&b)); + assert_ne!(a, &*b); + unsafe { a.clone_to_uninit(ptr::from_mut::(&mut b)) }; + assert_eq!(a, &*b); +} diff --git a/std/src/lib.rs b/std/src/lib.rs index ee6f5a6f3c0d5..5cc6376a32d72 100644 --- a/std/src/lib.rs +++ b/std/src/lib.rs @@ -323,6 +323,7 @@ // tidy-alphabetical-start #![feature(c_str_module)] #![feature(char_internals)] +#![feature(clone_to_uninit)] #![feature(core_intrinsics)] #![feature(core_io_borrowed_buf)] #![feature(duration_constants)] diff --git a/std/src/path.rs b/std/src/path.rs index 80163667636ae..d6c78883f2804 100644 --- a/std/src/path.rs +++ b/std/src/path.rs @@ -70,6 +70,8 @@ #[cfg(test)] mod tests; +use core::clone::CloneToUninit; + use crate::borrow::{Borrow, Cow}; use crate::collections::TryReserveError; use crate::error::Error; @@ -3109,6 +3111,15 @@ impl Path { } } +#[unstable(feature = "clone_to_uninit", issue = "126799")] +unsafe impl CloneToUninit for Path { + #[cfg_attr(debug_assertions, track_caller)] + unsafe fn clone_to_uninit(&self, dst: *mut Self) { + // SAFETY: Path is just a wrapper around OsStr + unsafe { self.inner.clone_to_uninit(core::ptr::addr_of_mut!((*dst).inner)) } + } +} + #[stable(feature = "rust1", since = "1.0.0")] impl AsRef for Path { #[inline] diff --git a/std/src/path/tests.rs b/std/src/path/tests.rs index a12e42cba0c5c..6436872087d6c 100644 --- a/std/src/path/tests.rs +++ b/std/src/path/tests.rs @@ -3,6 +3,8 @@ use core::hint::black_box; use super::*; use crate::collections::{BTreeSet, HashSet}; use crate::hash::DefaultHasher; +use crate::mem::MaybeUninit; +use crate::ptr; #[allow(unknown_lints, unused_macro_rules)] macro_rules! t ( @@ -2054,3 +2056,20 @@ fn bench_hash_path_long(b: &mut test::Bencher) { black_box(hasher.finish()); } + +#[test] +fn clone_to_uninit() { + let a = Path::new("hello.txt"); + + let mut storage = vec![MaybeUninit::::uninit(); size_of_val::(a)]; + unsafe { a.clone_to_uninit(ptr::from_mut::<[_]>(storage.as_mut_slice()) as *mut Path) }; + assert_eq!(a.as_os_str().as_encoded_bytes(), unsafe { + MaybeUninit::slice_assume_init_ref(&storage) + }); + + let mut b: Box = Path::new("world.exe").into(); + assert_eq!(size_of_val::(a), size_of_val::(&b)); + assert_ne!(a, &*b); + unsafe { a.clone_to_uninit(ptr::from_mut::(&mut b)) }; + assert_eq!(a, &*b); +} diff --git a/std/src/sys/os_str/bytes.rs b/std/src/sys/os_str/bytes.rs index 0f8bd6453528e..8529207366e93 100644 --- a/std/src/sys/os_str/bytes.rs +++ b/std/src/sys/os_str/bytes.rs @@ -1,6 +1,9 @@ //! The underlying OsString/OsStr implementation on Unix and many other //! systems: just a `Vec`/`[u8]`. +use core::clone::CloneToUninit; +use core::ptr::addr_of_mut; + use crate::borrow::Cow; use crate::collections::TryReserveError; use crate::fmt::Write; @@ -345,3 +348,12 @@ impl Slice { self.inner.eq_ignore_ascii_case(&other.inner) } } + +#[unstable(feature = "clone_to_uninit", issue = "126799")] +unsafe impl CloneToUninit for Slice { + #[cfg_attr(debug_assertions, track_caller)] + unsafe fn clone_to_uninit(&self, dst: *mut Self) { + // SAFETY: we're just a wrapper around [u8] + unsafe { self.inner.clone_to_uninit(addr_of_mut!((*dst).inner)) } + } +} diff --git a/std/src/sys/os_str/wtf8.rs b/std/src/sys/os_str/wtf8.rs index ed975ba58b5e2..e5755a4b87443 100644 --- a/std/src/sys/os_str/wtf8.rs +++ b/std/src/sys/os_str/wtf8.rs @@ -1,5 +1,8 @@ //! The underlying OsString/OsStr implementation on Windows is a //! wrapper around the "WTF-8" encoding; see the `wtf8` module for more. +use core::clone::CloneToUninit; +use core::ptr::addr_of_mut; + use crate::borrow::Cow; use crate::collections::TryReserveError; use crate::rc::Rc; @@ -268,3 +271,12 @@ impl Slice { self.inner.eq_ignore_ascii_case(&other.inner) } } + +#[unstable(feature = "clone_to_uninit", issue = "126799")] +unsafe impl CloneToUninit for Slice { + #[cfg_attr(debug_assertions, track_caller)] + unsafe fn clone_to_uninit(&self, dst: *mut Self) { + // SAFETY: we're just a wrapper around Wtf8 + unsafe { self.inner.clone_to_uninit(addr_of_mut!((*dst).inner)) } + } +} diff --git a/std/src/sys_common/wtf8.rs b/std/src/sys_common/wtf8.rs index 277c9506febbb..2bdeff78ddfd6 100644 --- a/std/src/sys_common/wtf8.rs +++ b/std/src/sys_common/wtf8.rs @@ -19,12 +19,14 @@ mod tests; use core::char::{encode_utf16_raw, encode_utf8_raw}; +use core::clone::CloneToUninit; use core::str::next_code_point; use crate::borrow::Cow; use crate::collections::TryReserveError; use crate::hash::{Hash, Hasher}; use crate::iter::FusedIterator; +use crate::ptr::addr_of_mut; use crate::rc::Rc; use crate::sync::Arc; use crate::sys_common::AsInner; @@ -1046,3 +1048,12 @@ impl Hash for Wtf8 { 0xfeu8.hash(state) } } + +#[unstable(feature = "clone_to_uninit", issue = "126799")] +unsafe impl CloneToUninit for Wtf8 { + #[cfg_attr(debug_assertions, track_caller)] + unsafe fn clone_to_uninit(&self, dst: *mut Self) { + // SAFETY: we're just a wrapper around [u8] + unsafe { self.bytes.clone_to_uninit(addr_of_mut!((*dst).bytes)) } + } +}