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rust: alloc: remove our fork of the alloc crate

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It is not used anymore as `VecExt` now provides the functionality we
depend on.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-5-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This commit is contained in:
Wedson Almeida Filho
2024-03-27 22:35:57 -03:00
committed by Miguel Ojeda
parent 11795ae4cc
commit 9d0441bab7
15 changed files with 0 additions and 9885 deletions
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rust/alloc/README.md
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# `alloc`
These source files come from the Rust standard library, hosted in
the <https://github.com/rust-lang/rust> repository, licensed under
"Apache-2.0 OR MIT" and adapted for kernel use. For copyright details,
see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>.
Please note that these files should be kept as close as possible to
upstream. In general, only additions should be performed (e.g. new
methods). Eventually, changes should make it into upstream so that,
at some point, this fork can be dropped from the kernel tree.
The Rust upstream version on top of which these files are based matches
the output of `scripts/min-tool-version.sh rustc`.
## Rationale
On one hand, kernel folks wanted to keep `alloc` in-tree to have more
freedom in both workflow and actual features if actually needed
(e.g. receiver types if we ended up using them), which is reasonable.
On the other hand, Rust folks wanted to keep `alloc` as close as
upstream as possible and avoid as much divergence as possible, which
is also reasonable.
We agreed on a middle-ground: we would keep a subset of `alloc`
in-tree that would be as small and as close as possible to upstream.
Then, upstream can start adding the functions that we add to `alloc`
etc., until we reach a point where the kernel already knows exactly
what it needs in `alloc` and all the new methods are merged into
upstream, so that we can drop `alloc` from the kernel tree and go back
to using the upstream one.
By doing this, the kernel can go a bit faster now, and Rust can
slowly incorporate and discuss the changes as needed.

452
rust/alloc/alloc.rs
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// SPDX-License-Identifier: Apache-2.0 OR MIT
//! Memory allocation APIs
#![stable(feature = "alloc_module", since = "1.28.0")]
#[cfg(not(test))]
use core::hint;
#[cfg(not(test))]
use core::ptr::{self, NonNull};
#[stable(feature = "alloc_module", since = "1.28.0")]
#[doc(inline)]
pub use core::alloc::*;
#[cfg(test)]
mod tests;
extern "Rust" {
// These are the magic symbols to call the global allocator. rustc generates
// them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute
// (the code expanding that attribute macro generates those functions), or to call
// the default implementations in std (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
// otherwise.
// The rustc fork of LLVM 14 and earlier also special-cases these function names to be able to optimize them
// like `malloc`, `realloc`, and `free`, respectively.
#[rustc_allocator]
#[rustc_nounwind]
fn __rust_alloc(size: usize, align: usize) -> *mut u8;
#[rustc_deallocator]
#[rustc_nounwind]
fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
#[rustc_reallocator]
#[rustc_nounwind]
fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
#[rustc_allocator_zeroed]
#[rustc_nounwind]
fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
static __rust_no_alloc_shim_is_unstable: u8;
}
/// The global memory allocator.
///
/// This type implements the [`Allocator`] trait by forwarding calls
/// to the allocator registered with the `#[global_allocator]` attribute
/// if there is one, or the `std` crate’s default.
///
/// Note: while this type is unstable, the functionality it provides can be
/// accessed through the [free functions in `alloc`](self#functions).
#[unstable(feature = "allocator_api", issue = "32838")]
#[derive(Copy, Clone, Default, Debug)]
#[cfg(not(test))]
pub struct Global;
#[cfg(test)]
pub use std::alloc::Global;
/// Allocate memory with the global allocator.
///
/// This function forwards calls to the [`GlobalAlloc::alloc`] method
/// of the allocator registered with the `#[global_allocator]` attribute
/// if there is one, or the `std` crate’s default.
///
/// This function is expected to be deprecated in favor of the `alloc` method
/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
///
/// # Safety
///
/// See [`GlobalAlloc::alloc`].
///
/// # Examples
///
/// ```
/// use std::alloc::{alloc, dealloc, handle_alloc_error, Layout};
///
/// unsafe {
/// let layout = Layout::new::<u16>();
/// let ptr = alloc(layout);
/// if ptr.is_null() {
/// handle_alloc_error(layout);
/// }
///
/// *(ptr as *mut u16) = 42;
/// assert_eq!(*(ptr as *mut u16), 42);
///
/// dealloc(ptr, layout);
/// }
/// ```
#[stable(feature = "global_alloc", since = "1.28.0")]
#[must_use = "losing the pointer will leak memory"]
#[inline]
pub unsafe fn alloc(layout: Layout) -> *mut u8 {
unsafe {
// Make sure we don't accidentally allow omitting the allocator shim in
// stable code until it is actually stabilized.
core::ptr::read_volatile(&__rust_no_alloc_shim_is_unstable);
__rust_alloc(layout.size(), layout.align())
}
}
/// Deallocate memory with the global allocator.
///
/// This function forwards calls to the [`GlobalAlloc::dealloc`] method
/// of the allocator registered with the `#[global_allocator]` attribute
/// if there is one, or the `std` crate’s default.
///
/// This function is expected to be deprecated in favor of the `dealloc` method
/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
///
/// # Safety
///
/// See [`GlobalAlloc::dealloc`].
#[stable(feature = "global_alloc", since = "1.28.0")]
#[inline]
pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
}
/// Reallocate memory with the global allocator.
///
/// This function forwards calls to the [`GlobalAlloc::realloc`] method
/// of the allocator registered with the `#[global_allocator]` attribute
/// if there is one, or the `std` crate’s default.
///
/// This function is expected to be deprecated in favor of the `realloc` method
/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
///
/// # Safety
///
/// See [`GlobalAlloc::realloc`].
#[stable(feature = "global_alloc", since = "1.28.0")]
#[must_use = "losing the pointer will leak memory"]
#[inline]
pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
unsafe { __rust_realloc(ptr, layout.size(), layout.align(), new_size) }
}
/// Allocate zero-initialized memory with the global allocator.
///
/// This function forwards calls to the [`GlobalAlloc::alloc_zeroed`] method
/// of the allocator registered with the `#[global_allocator]` attribute
/// if there is one, or the `std` crate’s default.
///
/// This function is expected to be deprecated in favor of the `alloc_zeroed` method
/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
///
/// # Safety
///
/// See [`GlobalAlloc::alloc_zeroed`].
///
/// # Examples
///
/// ```
/// use std::alloc::{alloc_zeroed, dealloc, Layout};
///
/// unsafe {
/// let layout = Layout::new::<u16>();
/// let ptr = alloc_zeroed(layout);
///
/// assert_eq!(*(ptr as *mut u16), 0);
///
/// dealloc(ptr, layout);
/// }
/// ```
#[stable(feature = "global_alloc", since = "1.28.0")]
#[must_use = "losing the pointer will leak memory"]
#[inline]
pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
unsafe { __rust_alloc_zeroed(layout.size(), layout.align()) }
}
#[cfg(not(test))]
impl Global {
#[inline]
fn alloc_impl(&self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocError> {
match layout.size() {
0 => Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0)),
// SAFETY: `layout` is non-zero in size,
size => unsafe {
let raw_ptr = if zeroed { alloc_zeroed(layout) } else { alloc(layout) };
let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
Ok(NonNull::slice_from_raw_parts(ptr, size))
},
}
}
// SAFETY: Same as `Allocator::grow`
#[inline]
unsafe fn grow_impl(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
zeroed: bool,
) -> Result<NonNull<[u8]>, AllocError> {
debug_assert!(
new_layout.size() >= old_layout.size(),
"`new_layout.size()` must be greater than or equal to `old_layout.size()`"
);
match old_layout.size() {
0 => self.alloc_impl(new_layout, zeroed),
// SAFETY: `new_size` is non-zero as `old_size` is greater than or equal to `new_size`
// as required by safety conditions. Other conditions must be upheld by the caller
old_size if old_layout.align() == new_layout.align() => unsafe {
let new_size = new_layout.size();
// `realloc` probably checks for `new_size >= old_layout.size()` or something similar.
hint::assert_unchecked(new_size >= old_layout.size());
let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
if zeroed {
raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
}
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
},
// SAFETY: because `new_layout.size()` must be greater than or equal to `old_size`,
// both the old and new memory allocation are valid for reads and writes for `old_size`
// bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
// `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
// for `dealloc` must be upheld by the caller.
old_size => unsafe {
let new_ptr = self.alloc_impl(new_layout, zeroed)?;
ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), old_size);
self.deallocate(ptr, old_layout);
Ok(new_ptr)
},
}
}
}
#[unstable(feature = "allocator_api", issue = "32838")]
#[cfg(not(test))]
unsafe impl Allocator for Global {
#[inline]
fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
self.alloc_impl(layout, false)
}
#[inline]
fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
self.alloc_impl(layout, true)
}
#[inline]
unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
if layout.size() != 0 {
// SAFETY: `layout` is non-zero in size,
// other conditions must be upheld by the caller
unsafe { dealloc(ptr.as_ptr(), layout) }
}
}
#[inline]
unsafe fn grow(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
) -> Result<NonNull<[u8]>, AllocError> {
// SAFETY: all conditions must be upheld by the caller
unsafe { self.grow_impl(ptr, old_layout, new_layout, false) }
}
#[inline]
unsafe fn grow_zeroed(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
) -> Result<NonNull<[u8]>, AllocError> {
// SAFETY: all conditions must be upheld by the caller
unsafe { self.grow_impl(ptr, old_layout, new_layout, true) }
}
#[inline]
unsafe fn shrink(
&self,
ptr: NonNull<u8>,
old_layout: Layout,
new_layout: Layout,
) -> Result<NonNull<[u8]>, AllocError> {
debug_assert!(
new_layout.size() <= old_layout.size(),
"`new_layout.size()` must be smaller than or equal to `old_layout.size()`"
);
match new_layout.size() {
// SAFETY: conditions must be upheld by the caller
0 => unsafe {
self.deallocate(ptr, old_layout);
Ok(NonNull::slice_from_raw_parts(new_layout.dangling(), 0))
},
// SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
new_size if old_layout.align() == new_layout.align() => unsafe {
// `realloc` probably checks for `new_size <= old_layout.size()` or something similar.
hint::assert_unchecked(new_size <= old_layout.size());
let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
},
// SAFETY: because `new_size` must be smaller than or equal to `old_layout.size()`,
// both the old and new memory allocation are valid for reads and writes for `new_size`
// bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
// `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
// for `dealloc` must be upheld by the caller.
new_size => unsafe {
let new_ptr = self.allocate(new_layout)?;
ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), new_size);
self.deallocate(ptr, old_layout);
Ok(new_ptr)
},
}
}
}
/// The allocator for unique pointers.
#[cfg(all(not(no_global_oom_handling), not(test)))]
#[lang = "exchange_malloc"]
#[inline]
unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
match Global.allocate(layout) {
Ok(ptr) => ptr.as_mut_ptr(),
Err(_) => handle_alloc_error(layout),
}
}
// # Allocation error handler
#[cfg(not(no_global_oom_handling))]
extern "Rust" {
// This is the magic symbol to call the global alloc error handler. rustc generates
// it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
// default implementations below (`__rdl_oom`) otherwise.
fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
}
/// Signal a memory allocation error.
///
/// Callers of memory allocation APIs wishing to cease execution
/// in response to an allocation error are encouraged to call this function,
/// rather than directly invoking [`panic!`] or similar.
///
/// This function is guaranteed to diverge (not return normally with a value), but depending on
/// global configuration, it may either panic (resulting in unwinding or aborting as per
/// configuration for all panics), or abort the process (with no unwinding).
///
/// The default behavior is:
///
/// * If the binary links against `std` (typically the case), then
/// print a message to standard error and abort the process.
/// This behavior can be replaced with [`set_alloc_error_hook`] and [`take_alloc_error_hook`].
/// Future versions of Rust may panic by default instead.
///
/// * If the binary does not link against `std` (all of its crates are marked
/// [`#![no_std]`][no_std]), then call [`panic!`] with a message.
/// [The panic handler] applies as to any panic.
///
/// [`set_alloc_error_hook`]: ../../std/alloc/fn.set_alloc_error_hook.html
/// [`take_alloc_error_hook`]: ../../std/alloc/fn.take_alloc_error_hook.html
/// [The panic handler]: https://doc.rust-lang.org/reference/runtime.html#the-panic_handler-attribute
/// [no_std]: https://doc.rust-lang.org/reference/names/preludes.html#the-no_std-attribute
#[stable(feature = "global_alloc", since = "1.28.0")]
#[rustc_const_unstable(feature = "const_alloc_error", issue = "92523")]
#[cfg(all(not(no_global_oom_handling), not(test)))]
#[cold]
pub const fn handle_alloc_error(layout: Layout) -> ! {
const fn ct_error(_: Layout) -> ! {
panic!("allocation failed");
}
#[inline]
fn rt_error(layout: Layout) -> ! {
unsafe {
__rust_alloc_error_handler(layout.size(), layout.align());
}
}
#[cfg(not(feature = "panic_immediate_abort"))]
unsafe {
core::intrinsics::const_eval_select((layout,), ct_error, rt_error)
}
#[cfg(feature = "panic_immediate_abort")]
ct_error(layout)
}
// For alloc test `std::alloc::handle_alloc_error` can be used directly.
#[cfg(all(not(no_global_oom_handling), test))]
pub use std::alloc::handle_alloc_error;
#[cfg(all(not(no_global_oom_handling), not(test)))]
#[doc(hidden)]
#[allow(unused_attributes)]
#[unstable(feature = "alloc_internals", issue = "none")]
pub mod __alloc_error_handler {
// called via generated `__rust_alloc_error_handler` if there is no
// `#[alloc_error_handler]`.
#[rustc_std_internal_symbol]
pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
extern "Rust" {
// This symbol is emitted by rustc next to __rust_alloc_error_handler.
// Its value depends on the -Zoom={panic,abort} compiler option.
static __rust_alloc_error_handler_should_panic: u8;
}
if unsafe { __rust_alloc_error_handler_should_panic != 0 } {
panic!("memory allocation of {size} bytes failed")
} else {
core::panicking::panic_nounwind_fmt(
format_args!("memory allocation of {size} bytes failed"),
/* force_no_backtrace */ false,
)
}
}
}
#[cfg(not(no_global_oom_handling))]
/// Specialize clones into pre-allocated, uninitialized memory.
/// Used by `Box::clone` and `Rc`/`Arc::make_mut`.
pub(crate) trait WriteCloneIntoRaw: Sized {
unsafe fn write_clone_into_raw(&self, target: *mut Self);
}
#[cfg(not(no_global_oom_handling))]
impl<T: Clone> WriteCloneIntoRaw for T {
#[inline]
default unsafe fn write_clone_into_raw(&self, target: *mut Self) {
// Having allocated *first* may allow the optimizer to create
// the cloned value in-place, skipping the local and move.
unsafe { target.write(self.clone()) };
}
}
#[cfg(not(no_global_oom_handling))]
impl<T: Copy> WriteCloneIntoRaw for T {
#[inline]
unsafe fn write_clone_into_raw(&self, target: *mut Self) {
// We can always copy in-place, without ever involving a local value.
unsafe { target.copy_from_nonoverlapping(self, 1) };
}
}

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rust/alloc/boxed.rs
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rust/alloc/collections/mod.rs
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// SPDX-License-Identifier: Apache-2.0 OR MIT
//! Collection types.
#![stable(feature = "rust1", since = "1.0.0")]
#[cfg(not(no_global_oom_handling))]
pub mod binary_heap;
#[cfg(not(no_global_oom_handling))]
mod btree;
#[cfg(not(no_global_oom_handling))]
pub mod linked_list;
#[cfg(not(no_global_oom_handling))]
pub mod vec_deque;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
pub mod btree_map {
//! An ordered map based on a B-Tree.
#[stable(feature = "rust1", since = "1.0.0")]
pub use super::btree::map::*;
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
pub mod btree_set {
//! An ordered set based on a B-Tree.
#[stable(feature = "rust1", since = "1.0.0")]
pub use super::btree::set::*;
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use binary_heap::BinaryHeap;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use btree_map::BTreeMap;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use btree_set::BTreeSet;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use linked_list::LinkedList;
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(no_inline)]
pub use vec_deque::VecDeque;
use crate::alloc::{Layout, LayoutError};
use core::fmt::Display;
/// The error type for `try_reserve` methods.
#[derive(Clone, PartialEq, Eq, Debug)]
#[stable(feature = "try_reserve", since = "1.57.0")]
pub struct TryReserveError {
kind: TryReserveErrorKind,
}
impl TryReserveError {
/// Details about the allocation that caused the error
#[inline]
#[must_use]
#[unstable(
feature = "try_reserve_kind",
reason = "Uncertain how much info should be exposed",
issue = "48043"
)]
pub fn kind(&self) -> TryReserveErrorKind {
self.kind.clone()
}
}
/// Details of the allocation that caused a `TryReserveError`
#[derive(Clone, PartialEq, Eq, Debug)]
#[unstable(
feature = "try_reserve_kind",
reason = "Uncertain how much info should be exposed",
issue = "48043"
)]
pub enum TryReserveErrorKind {
/// Error due to the computed capacity exceeding the collection's maximum
/// (usually `isize::MAX` bytes).
CapacityOverflow,
/// The memory allocator returned an error
AllocError {
/// The layout of allocation request that failed
layout: Layout,
#[doc(hidden)]
#[unstable(
feature = "container_error_extra",
issue = "none",
reason = "\
Enable exposing the allocator’s custom error value \
if an associated type is added in the future: \
https://github.com/rust-lang/wg-allocators/issues/23"
)]
non_exhaustive: (),
},
}
#[unstable(
feature = "try_reserve_kind",
reason = "Uncertain how much info should be exposed",
issue = "48043"
)]
impl From<TryReserveErrorKind> for TryReserveError {
#[inline]
fn from(kind: TryReserveErrorKind) -> Self {
Self { kind }
}
}
#[unstable(feature = "try_reserve_kind", reason = "new API", issue = "48043")]
impl From<LayoutError> for TryReserveErrorKind {
/// Always evaluates to [`TryReserveErrorKind::CapacityOverflow`].
#[inline]
fn from(_: LayoutError) -> Self {
TryReserveErrorKind::CapacityOverflow
}
}
#[stable(feature = "try_reserve", since = "1.57.0")]
impl Display for TryReserveError {
fn fmt(
&self,
fmt: &mut core::fmt::Formatter<'_>,
) -> core::result::Result<(), core::fmt::Error> {
fmt.write_str("memory allocation failed")?;
let reason = match self.kind {
TryReserveErrorKind::CapacityOverflow => {
" because the computed capacity exceeded the collection's maximum"
}
TryReserveErrorKind::AllocError { .. } => {
" because the memory allocator returned an error"
}
};
fmt.write_str(reason)
}
}
/// An intermediate trait for specialization of `Extend`.
#[doc(hidden)]
#[cfg(not(no_global_oom_handling))]
trait SpecExtend<I: IntoIterator> {
/// Extends `self` with the contents of the given iterator.
fn spec_extend(&mut self, iter: I);
}
#[stable(feature = "try_reserve", since = "1.57.0")]
impl core::error::Error for TryReserveError {}

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rust/alloc/lib.rs
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// SPDX-License-Identifier: Apache-2.0 OR MIT
//! # The Rust core allocation and collections library
//!
//! This library provides smart pointers and collections for managing
//! heap-allocated values.
//!
//! This library, like core, normally doesn’t need to be used directly
//! since its contents are re-exported in the [`std` crate](../std/index.html).
//! Crates that use the `#![no_std]` attribute however will typically
//! not depend on `std`, so they’d use this crate instead.
//!
//! ## Boxed values
//!
//! The [`Box`] type is a smart pointer type. There can only be one owner of a
//! [`Box`], and the owner can decide to mutate the contents, which live on the
//! heap.
//!
//! This type can be sent among threads efficiently as the size of a `Box` value
//! is the same as that of a pointer. Tree-like data structures are often built
//! with boxes because each node often has only one owner, the parent.
//!
//! ## Reference counted pointers
//!
//! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended
//! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and
//! only allows access to `&T`, a shared reference.
//!
//! This type is useful when inherited mutability (such as using [`Box`]) is too
//! constraining for an application, and is often paired with the [`Cell`] or
//! [`RefCell`] types in order to allow mutation.
//!
//! ## Atomically reference counted pointers
//!
//! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It
//! provides all the same functionality of [`Rc`], except it requires that the
//! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself
//! sendable while [`Rc<T>`][`Rc`] is not.
//!
//! This type allows for shared access to the contained data, and is often
//! paired with synchronization primitives such as mutexes to allow mutation of
//! shared resources.
//!
//! ## Collections
//!
//! Implementations of the most common general purpose data structures are
//! defined in this library. They are re-exported through the
//! [standard collections library](../std/collections/index.html).
//!
//! ## Heap interfaces
//!
//! The [`alloc`](alloc/index.html) module defines the low-level interface to the
//! default global allocator. It is not compatible with the libc allocator API.
//!
//! [`Arc`]: sync
//! [`Box`]: boxed
//! [`Cell`]: core::cell
//! [`Rc`]: rc
//! [`RefCell`]: core::cell
// To run alloc tests without x.py without ending up with two copies of alloc, Miri needs to be
// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
// rustc itself never sets the feature, so this line has no effect there.
#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
//
#![allow(unused_attributes)]
#![stable(feature = "alloc", since = "1.36.0")]
#![doc(
html_playground_url = "https://play.rust-lang.org/",
issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
test(no_crate_inject, attr(allow(unused_variables), deny(warnings)))
)]
#![doc(cfg_hide(
not(test),
not(any(test, bootstrap)),
any(not(feature = "miri-test-libstd"), test, doctest),
no_global_oom_handling,
not(no_global_oom_handling),
not(no_rc),
not(no_sync),
target_has_atomic = "ptr"
))]
#![doc(rust_logo)]
#![feature(rustdoc_internals)]
#![no_std]
#![needs_allocator]
// Lints:
#![deny(unsafe_op_in_unsafe_fn)]
#![deny(fuzzy_provenance_casts)]
#![warn(deprecated_in_future)]
#![warn(missing_debug_implementations)]
#![warn(missing_docs)]
#![allow(explicit_outlives_requirements)]
#![warn(multiple_supertrait_upcastable)]
#![allow(internal_features)]
#![allow(rustdoc::redundant_explicit_links)]
//
// Library features:
// tidy-alphabetical-start
#![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))]
#![cfg_attr(not(no_global_oom_handling), feature(const_btree_len))]
#![cfg_attr(test, feature(is_sorted))]
#![cfg_attr(test, feature(new_uninit))]
#![feature(alloc_layout_extra)]
#![feature(allocator_api)]
#![feature(array_chunks)]
#![feature(array_into_iter_constructors)]
#![feature(array_windows)]
#![feature(ascii_char)]
#![feature(assert_matches)]
#![feature(async_iterator)]
#![feature(coerce_unsized)]
#![feature(const_align_of_val)]
#![feature(const_box)]
#![cfg_attr(not(no_borrow), feature(const_cow_is_borrowed))]
#![feature(const_eval_select)]
#![feature(const_maybe_uninit_as_mut_ptr)]
#![feature(const_maybe_uninit_write)]
#![feature(const_pin)]
#![feature(const_refs_to_cell)]
#![feature(const_size_of_val)]
#![feature(const_waker)]
#![feature(core_intrinsics)]
#![feature(deprecated_suggestion)]
#![feature(dispatch_from_dyn)]
#![feature(error_generic_member_access)]
#![feature(error_in_core)]
#![feature(exact_size_is_empty)]
#![feature(extend_one)]
#![feature(fmt_internals)]
#![feature(fn_traits)]
#![feature(hasher_prefixfree_extras)]
#![feature(hint_assert_unchecked)]
#![feature(inline_const)]
#![feature(inplace_iteration)]
#![feature(iter_advance_by)]
#![feature(iter_next_chunk)]
#![feature(iter_repeat_n)]
#![feature(layout_for_ptr)]
#![feature(maybe_uninit_slice)]
#![feature(maybe_uninit_uninit_array)]
#![feature(maybe_uninit_uninit_array_transpose)]
#![feature(non_null_convenience)]
#![feature(panic_internals)]
#![feature(pattern)]
#![feature(ptr_internals)]
#![feature(ptr_metadata)]
#![feature(ptr_sub_ptr)]
#![feature(receiver_trait)]
#![feature(set_ptr_value)]
#![feature(sized_type_properties)]
#![feature(slice_from_ptr_range)]
#![feature(slice_ptr_get)]
#![feature(slice_ptr_len)]
#![feature(slice_range)]
#![feature(std_internals)]
#![feature(str_internals)]
#![feature(strict_provenance)]
#![feature(trusted_fused)]
#![feature(trusted_len)]
#![feature(trusted_random_access)]
#![feature(try_trait_v2)]
#![feature(tuple_trait)]
#![feature(unchecked_math)]
#![feature(unicode_internals)]
#![feature(unsize)]
#![feature(utf8_chunks)]
// tidy-alphabetical-end
//
// Language features:
// tidy-alphabetical-start
#![cfg_attr(not(test), feature(coroutine_trait))]
#![cfg_attr(test, feature(panic_update_hook))]
#![cfg_attr(test, feature(test))]
#![feature(allocator_internals)]
#![feature(allow_internal_unstable)]
#![feature(associated_type_bounds)]
#![feature(c_unwind)]
#![feature(cfg_sanitize)]
#![feature(const_mut_refs)]
#![feature(const_precise_live_drops)]
#![feature(const_ptr_write)]
#![feature(const_trait_impl)]
#![feature(const_try)]
#![feature(decl_macro)]
#![feature(dropck_eyepatch)]
#![feature(exclusive_range_pattern)]
#![feature(fundamental)]
#![feature(hashmap_internals)]
#![feature(lang_items)]
#![feature(min_specialization)]
#![feature(multiple_supertrait_upcastable)]
#![feature(negative_impls)]
#![feature(never_type)]
#![feature(pointer_is_aligned)]
#![feature(rustc_allow_const_fn_unstable)]
#![feature(rustc_attrs)]
#![feature(slice_internals)]
#![feature(staged_api)]
#![feature(stmt_expr_attributes)]
#![feature(unboxed_closures)]
#![feature(unsized_fn_params)]
#![feature(with_negative_coherence)]
// tidy-alphabetical-end
//
// Rustdoc features:
#![feature(doc_cfg)]
#![feature(doc_cfg_hide)]
// Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
// blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
// that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs
// from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
#![feature(intra_doc_pointers)]
// Allow testing this library
#[cfg(test)]
#[macro_use]
extern crate std;
#[cfg(test)]
extern crate test;
#[cfg(test)]
mod testing;
// Module with internal macros used by other modules (needs to be included before other modules).
#[cfg(not(no_macros))]
#[macro_use]
mod macros;
mod raw_vec;
// Heaps provided for low-level allocation strategies
pub mod alloc;
// Primitive types using the heaps above
// Need to conditionally define the mod from `boxed.rs` to avoid
// duplicating the lang-items when building in test cfg; but also need
// to allow code to have `use boxed::Box;` declarations.
#[cfg(not(test))]
pub mod boxed;
#[cfg(test)]
mod boxed {
pub use std::boxed::Box;
}
#[cfg(not(no_borrow))]
pub mod borrow;
pub mod collections;
#[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
pub mod ffi;
#[cfg(not(no_fmt))]
pub mod fmt;
#[cfg(not(no_rc))]
pub mod rc;
pub mod slice;
#[cfg(not(no_str))]
pub mod str;
#[cfg(not(no_string))]
pub mod string;
#[cfg(all(not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
pub mod sync;
#[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
pub mod task;
#[cfg(test)]
mod tests;
pub mod vec;
#[doc(hidden)]
#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
pub mod __export {
pub use core::format_args;
}
#[cfg(test)]
#[allow(dead_code)] // Not used in all configurations
pub(crate) mod test_helpers {
/// Copied from `std::test_helpers::test_rng`, since these tests rely on the
/// seed not being the same for every RNG invocation too.
pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
use std::hash::{BuildHasher, Hash, Hasher};
let mut hasher = std::hash::RandomState::new().build_hasher();
std::panic::Location::caller().hash(&mut hasher);
let hc64 = hasher.finish();
let seed_vec =
hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<crate::vec::Vec<u8>>();
let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
rand::SeedableRng::from_seed(seed)
}
}

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rust/alloc/vec/drain.rs
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// SPDX-License-Identifier: Apache-2.0 OR MIT
use crate::alloc::{Allocator, Global};
use core::fmt;
use core::iter::{FusedIterator, TrustedLen};
use core::mem::{self, ManuallyDrop, SizedTypeProperties};
use core::ptr::{self, NonNull};
use core::slice::{self};
use super::Vec;
/// A draining iterator for `Vec<T>`.
///
/// This `struct` is created by [`Vec::drain`].
/// See its documentation for more.
///
/// # Example
///
/// ```
/// let mut v = vec![0, 1, 2];
/// let iter: std::vec::Drain<'_, _> = v.drain(..);
/// ```
#[stable(feature = "drain", since = "1.6.0")]
pub struct Drain<
'a,
T: 'a,
#[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + 'a = Global,
> {
/// Index of tail to preserve
pub(super) tail_start: usize,
/// Length of tail
pub(super) tail_len: usize,
/// Current remaining range to remove
pub(super) iter: slice::Iter<'a, T>,
pub(super) vec: NonNull<Vec<T, A>>,
}
#[stable(feature = "collection_debug", since = "1.17.0")]
impl<T: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, T, A> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("Drain").field(&self.iter.as_slice()).finish()
}
}
impl<'a, T, A: Allocator> Drain<'a, T, A> {
/// Returns the remaining items of this iterator as a slice.
///
/// # Examples
///
/// ```
/// let mut vec = vec!['a', 'b', 'c'];
/// let mut drain = vec.drain(..);
/// assert_eq!(drain.as_slice(), &['a', 'b', 'c']);
/// let _ = drain.next().unwrap();
/// assert_eq!(drain.as_slice(), &['b', 'c']);
/// ```
#[must_use]
#[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
pub fn as_slice(&self) -> &[T] {
self.iter.as_slice()
}
/// Returns a reference to the underlying allocator.
#[unstable(feature = "allocator_api", issue = "32838")]
#[must_use]
#[inline]
pub fn allocator(&self) -> &A {
unsafe { self.vec.as_ref().allocator() }
}
/// Keep unyielded elements in the source `Vec`.
///
/// # Examples
///
/// ```
/// #![feature(drain_keep_rest)]
///
/// let mut vec = vec!['a', 'b', 'c'];
/// let mut drain = vec.drain(..);
///
/// assert_eq!(drain.next().unwrap(), 'a');
///
/// // This call keeps 'b' and 'c' in the vec.
/// drain.keep_rest();
///
/// // If we wouldn't call `keep_rest()`,
/// // `vec` would be empty.
/// assert_eq!(vec, ['b', 'c']);
/// ```
#[unstable(feature = "drain_keep_rest", issue = "101122")]
pub fn keep_rest(self) {
// At this moment layout looks like this:
//
// [head] [yielded by next] [unyielded] [yielded by next_back] [tail]
// ^-- start \_________/-- unyielded_len \____/-- self.tail_len
// ^-- unyielded_ptr ^-- tail
//
// Normally `Drop` impl would drop [unyielded] and then move [tail] to the `start`.
// Here we want to
// 1. Move [unyielded] to `start`
// 2. Move [tail] to a new start at `start + len(unyielded)`
// 3. Update length of the original vec to `len(head) + len(unyielded) + len(tail)`
// a. In case of ZST, this is the only thing we want to do
// 4. Do *not* drop self, as everything is put in a consistent state already, there is nothing to do
let mut this = ManuallyDrop::new(self);
unsafe {
let source_vec = this.vec.as_mut();
let start = source_vec.len();
let tail = this.tail_start;
let unyielded_len = this.iter.len();
let unyielded_ptr = this.iter.as_slice().as_ptr();
// ZSTs have no identity, so we don't need to move them around.
if !T::IS_ZST {
let start_ptr = source_vec.as_mut_ptr().add(start);
// memmove back unyielded elements
if unyielded_ptr != start_ptr {
let src = unyielded_ptr;
let dst = start_ptr;
ptr::copy(src, dst, unyielded_len);
}
// memmove back untouched tail
if tail != (start + unyielded_len) {
let src = source_vec.as_ptr().add(tail);
let dst = start_ptr.add(unyielded_len);
ptr::copy(src, dst, this.tail_len);
}
}
source_vec.set_len(start + unyielded_len + this.tail_len);
}
}
}
#[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
impl<'a, T, A: Allocator> AsRef<[T]> for Drain<'a, T, A> {
fn as_ref(&self) -> &[T] {
self.as_slice()
}
}
#[stable(feature = "drain", since = "1.6.0")]
unsafe impl<T: Sync, A: Sync + Allocator> Sync for Drain<'_, T, A> {}
#[stable(feature = "drain", since = "1.6.0")]
unsafe impl<T: Send, A: Send + Allocator> Send for Drain<'_, T, A> {}
#[stable(feature = "drain", since = "1.6.0")]
impl<T, A: Allocator> Iterator for Drain<'_, T, A> {
type Item = T;
#[inline]
fn next(&mut self) -> Option<T> {
self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) })
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.iter.size_hint()
}
}
#[stable(feature = "drain", since = "1.6.0")]
impl<T, A: Allocator> DoubleEndedIterator for Drain<'_, T, A> {
#[inline]
fn next_back(&mut self) -> Option<T> {
self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) })
}
}
#[stable(feature = "drain", since = "1.6.0")]
impl<T, A: Allocator> Drop for Drain<'_, T, A> {
fn drop(&mut self) {
/// Moves back the un-`Drain`ed elements to restore the original `Vec`.
struct DropGuard<'r, 'a, T, A: Allocator>(&'r mut Drain<'a, T, A>);
impl<'r, 'a, T, A: Allocator> Drop for DropGuard<'r, 'a, T, A> {
fn drop(&mut self) {
if self.0.tail_len > 0 {
unsafe {
let source_vec = self.0.vec.as_mut();
// memmove back untouched tail, update to new length
let start = source_vec.len();
let tail = self.0.tail_start;
if tail != start {
let src = source_vec.as_ptr().add(tail);
let dst = source_vec.as_mut_ptr().add(start);
ptr::copy(src, dst, self.0.tail_len);
}
source_vec.set_len(start + self.0.tail_len);
}
}
}
}
let iter = mem::take(&mut self.iter);
let drop_len = iter.len();
let mut vec = self.vec;
if T::IS_ZST {
// ZSTs have no identity, so we don't need to move them around, we only need to drop the correct amount.
// this can be achieved by manipulating the Vec length instead of moving values out from `iter`.
unsafe {
let vec = vec.as_mut();
let old_len = vec.len();
vec.set_len(old_len + drop_len + self.tail_len);
vec.truncate(old_len + self.tail_len);
}
return;
}
// ensure elements are moved back into their appropriate places, even when drop_in_place panics
let _guard = DropGuard(self);
if drop_len == 0 {
return;
}
// as_slice() must only be called when iter.len() is > 0 because
// it also gets touched by vec::Splice which may turn it into a dangling pointer
// which would make it and the vec pointer point to different allocations which would
// lead to invalid pointer arithmetic below.
let drop_ptr = iter.as_slice().as_ptr();
unsafe {
// drop_ptr comes from a slice::Iter which only gives us a &[T] but for drop_in_place
// a pointer with mutable provenance is necessary. Therefore we must reconstruct
// it from the original vec but also avoid creating a &mut to the front since that could
// invalidate raw pointers to it which some unsafe code might rely on.
let vec_ptr = vec.as_mut().as_mut_ptr();
let drop_offset = drop_ptr.sub_ptr(vec_ptr);
let to_drop = ptr::slice_from_raw_parts_mut(vec_ptr.add(drop_offset), drop_len);
ptr::drop_in_place(to_drop);
}
}
}
#[stable(feature = "drain", since = "1.6.0")]
impl<T, A: Allocator> ExactSizeIterator for Drain<'_, T, A> {
fn is_empty(&self) -> bool {
self.iter.is_empty()
}
}
#[unstable(feature = "trusted_len", issue = "37572")]
unsafe impl<T, A: Allocator> TrustedLen for Drain<'_, T, A> {}
#[stable(feature = "fused", since = "1.26.0")]
impl<T, A: Allocator> FusedIterator for Drain<'_, T, A> {}

115
rust/alloc/vec/extract_if.rs
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@@ -1,115 +0,0 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
use crate::alloc::{Allocator, Global};
use core::ptr;
use core::slice;
use super::Vec;
/// An iterator which uses a closure to determine if an element should be removed.
///
/// This struct is created by [`Vec::extract_if`].
/// See its documentation for more.
///
/// # Example
///
/// ```
/// #![feature(extract_if)]
///
/// let mut v = vec![0, 1, 2];
/// let iter: std::vec::ExtractIf<'_, _, _> = v.extract_if(|x| *x % 2 == 0);
/// ```
#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
#[derive(Debug)]
#[must_use = "iterators are lazy and do nothing unless consumed"]
pub struct ExtractIf<
'a,
T,
F,
#[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
> where
F: FnMut(&mut T) -> bool,
{
pub(super) vec: &'a mut Vec<T, A>,
/// The index of the item that will be inspected by the next call to `next`.
pub(super) idx: usize,
/// The number of items that have been drained (removed) thus far.
pub(super) del: usize,
/// The original length of `vec` prior to draining.
pub(super) old_len: usize,
/// The filter test predicate.
pub(super) pred: F,
}
impl<T, F, A: Allocator> ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
/// Returns a reference to the underlying allocator.
#[unstable(feature = "allocator_api", issue = "32838")]
#[inline]
pub fn allocator(&self) -> &A {
self.vec.allocator()
}
}
#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
impl<T, F, A: Allocator> Iterator for ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
type Item = T;
fn next(&mut self) -> Option<T> {
unsafe {
while self.idx < self.old_len {
let i = self.idx;
let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len);
let drained = (self.pred)(&mut v[i]);
// Update the index *after* the predicate is called. If the index
// is updated prior and the predicate panics, the element at this
// index would be leaked.
self.idx += 1;
if drained {
self.del += 1;
return Some(ptr::read(&v[i]));
} else if self.del > 0 {
let del = self.del;
let src: *const T = &v[i];
let dst: *mut T = &mut v[i - del];
ptr::copy_nonoverlapping(src, dst, 1);
}
}
None
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
(0, Some(self.old_len - self.idx))
}
}
#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
impl<T, F, A: Allocator> Drop for ExtractIf<'_, T, F, A>
where
F: FnMut(&mut T) -> bool,
{
fn drop(&mut self) {
unsafe {
if self.idx < self.old_len && self.del > 0 {
// This is a pretty messed up state, and there isn't really an
// obviously right thing to do. We don't want to keep trying
// to execute `pred`, so we just backshift all the unprocessed
// elements and tell the vec that they still exist. The backshift
// is required to prevent a double-drop of the last successfully
// drained item prior to a panic in the predicate.
let ptr = self.vec.as_mut_ptr();
let src = ptr.add(self.idx);
let dst = src.sub(self.del);
let tail_len = self.old_len - self.idx;
src.copy_to(dst, tail_len);
}
self.vec.set_len(self.old_len - self.del);
}
}
}

484
rust/alloc/vec/into_iter.rs
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@@ -1,484 +0,0 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
#[cfg(not(no_global_oom_handling))]
use super::AsVecIntoIter;
use crate::alloc::{Allocator, Global};
#[cfg(not(no_global_oom_handling))]
use crate::collections::VecDeque;
use crate::raw_vec::RawVec;
use core::array;
use core::fmt;
use core::iter::{
FusedIterator, InPlaceIterable, SourceIter, TrustedFused, TrustedLen,
TrustedRandomAccessNoCoerce,
};
use core::marker::PhantomData;
use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
use core::num::NonZeroUsize;
#[cfg(not(no_global_oom_handling))]
use core::ops::Deref;
use core::ptr::{self, NonNull};
use core::slice::{self};
macro non_null {
(mut $place:expr, $t:ident) => {{
#![allow(unused_unsafe)] // we're sometimes used within an unsafe block
unsafe { &mut *(ptr::addr_of_mut!($place) as *mut NonNull<$t>) }
}},
($place:expr, $t:ident) => {{
#![allow(unused_unsafe)] // we're sometimes used within an unsafe block
unsafe { *(ptr::addr_of!($place) as *const NonNull<$t>) }
}},
}
/// An iterator that moves out of a vector.
///
/// This `struct` is created by the `into_iter` method on [`Vec`](super::Vec)
/// (provided by the [`IntoIterator`] trait).
///
/// # Example
///
/// ```
/// let v = vec![0, 1, 2];
/// let iter: std::vec::IntoIter<_> = v.into_iter();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_insignificant_dtor]
pub struct IntoIter<
T,
#[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
> {
pub(super) buf: NonNull<T>,
pub(super) phantom: PhantomData<T>,
pub(super) cap: usize,
// the drop impl reconstructs a RawVec from buf, cap and alloc
// to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
pub(super) alloc: ManuallyDrop<A>,
pub(super) ptr: NonNull<T>,
/// If T is a ZST, this is actually ptr+len. This encoding is picked so that
/// ptr == end is a quick test for the Iterator being empty, that works
/// for both ZST and non-ZST.
/// For non-ZSTs the pointer is treated as `NonNull<T>`
pub(super) end: *const T,
}
#[stable(feature = "vec_intoiter_debug", since = "1.13.0")]
impl<T: fmt::Debug, A: Allocator> fmt::Debug for IntoIter<T, A> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("IntoIter").field(&self.as_slice()).finish()
}
}
impl<T, A: Allocator> IntoIter<T, A> {
/// Returns the remaining items of this iterator as a slice.
///
/// # Examples
///
/// ```
/// let vec = vec!['a', 'b', 'c'];
/// let mut into_iter = vec.into_iter();
/// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
/// let _ = into_iter.next().unwrap();
/// assert_eq!(into_iter.as_slice(), &['b', 'c']);
/// ```
#[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
pub fn as_slice(&self) -> &[T] {
unsafe { slice::from_raw_parts(self.ptr.as_ptr(), self.len()) }
}
/// Returns the remaining items of this iterator as a mutable slice.
///
/// # Examples
///
/// ```
/// let vec = vec!['a', 'b', 'c'];
/// let mut into_iter = vec.into_iter();
/// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
/// into_iter.as_mut_slice()[2] = 'z';
/// assert_eq!(into_iter.next().unwrap(), 'a');
/// assert_eq!(into_iter.next().unwrap(), 'b');
/// assert_eq!(into_iter.next().unwrap(), 'z');
/// ```
#[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
pub fn as_mut_slice(&mut self) -> &mut [T] {
unsafe { &mut *self.as_raw_mut_slice() }
}
/// Returns a reference to the underlying allocator.
#[unstable(feature = "allocator_api", issue = "32838")]
#[inline]
pub fn allocator(&self) -> &A {
&self.alloc
}
fn as_raw_mut_slice(&mut self) -> *mut [T] {
ptr::slice_from_raw_parts_mut(self.ptr.as_ptr(), self.len())
}
/// Drops remaining elements and relinquishes the backing allocation.
/// This method guarantees it won't panic before relinquishing
/// the backing allocation.
///
/// This is roughly equivalent to the following, but more efficient
///
/// ```
/// # let mut into_iter = Vec::<u8>::with_capacity(10).into_iter();
/// let mut into_iter = std::mem::replace(&mut into_iter, Vec::new().into_iter());
/// (&mut into_iter).for_each(drop);
/// std::mem::forget(into_iter);
/// ```
///
/// This method is used by in-place iteration, refer to the vec::in_place_collect
/// documentation for an overview.
#[cfg(not(no_global_oom_handling))]
pub(super) fn forget_allocation_drop_remaining(&mut self) {
let remaining = self.as_raw_mut_slice();
// overwrite the individual fields instead of creating a new
// struct and then overwriting &mut self.
// this creates less assembly
self.cap = 0;
self.buf = unsafe { NonNull::new_unchecked(RawVec::NEW.ptr()) };
self.ptr = self.buf;
self.end = self.buf.as_ptr();
// Dropping the remaining elements can panic, so this needs to be
// done only after updating the other fields.
unsafe {
ptr::drop_in_place(remaining);
}
}
/// Forgets to Drop the remaining elements while still allowing the backing allocation to be freed.
pub(crate) fn forget_remaining_elements(&mut self) {
// For the ZST case, it is crucial that we mutate `end` here, not `ptr`.
// `ptr` must stay aligned, while `end` may be unaligned.
self.end = self.ptr.as_ptr();
}
#[cfg(not(no_global_oom_handling))]
#[inline]
pub(crate) fn into_vecdeque(self) -> VecDeque<T, A> {
// Keep our `Drop` impl from dropping the elements and the allocator
let mut this = ManuallyDrop::new(self);
// SAFETY: This allocation originally came from a `Vec`, so it passes
// all those checks. We have `this.buf` ≤ `this.ptr` ≤ `this.end`,
// so the `sub_ptr`s below cannot wrap, and will produce a well-formed
// range. `end` ≤ `buf + cap`, so the range will be in-bounds.
// Taking `alloc` is ok because nothing else is going to look at it,
// since our `Drop` impl isn't going to run so there's no more code.
unsafe {
let buf = this.buf.as_ptr();
let initialized = if T::IS_ZST {
// All the pointers are the same for ZSTs, so it's fine to
// say that they're all at the beginning of the "allocation".
0..this.len()
} else {
this.ptr.sub_ptr(this.buf)..this.end.sub_ptr(buf)
};
let cap = this.cap;
let alloc = ManuallyDrop::take(&mut this.alloc);
VecDeque::from_contiguous_raw_parts_in(buf, initialized, cap, alloc)
}
}
}
#[stable(feature = "vec_intoiter_as_ref", since = "1.46.0")]
impl<T, A: Allocator> AsRef<[T]> for IntoIter<T, A> {
fn as_ref(&self) -> &[T] {
self.as_slice()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
unsafe impl<T: Send, A: Allocator + Send> Send for IntoIter<T, A> {}
#[stable(feature = "rust1", since = "1.0.0")]
unsafe impl<T: Sync, A: Allocator + Sync> Sync for IntoIter<T, A> {}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T, A: Allocator> Iterator for IntoIter<T, A> {
type Item = T;
#[inline]
fn next(&mut self) -> Option<T> {
if T::IS_ZST {
if self.ptr.as_ptr() == self.end as *mut _ {
None
} else {
// `ptr` has to stay where it is to remain aligned, so we reduce the length by 1 by
// reducing the `end`.
self.end = self.end.wrapping_byte_sub(1);
// Make up a value of this ZST.
Some(unsafe { mem::zeroed() })
}
} else {
if self.ptr == non_null!(self.end, T) {
None
} else {
let old = self.ptr;
self.ptr = unsafe { old.add(1) };
Some(unsafe { ptr::read(old.as_ptr()) })
}
}
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
let exact = if T::IS_ZST {
self.end.addr().wrapping_sub(self.ptr.as_ptr().addr())
} else {
unsafe { non_null!(self.end, T).sub_ptr(self.ptr) }
};
(exact, Some(exact))
}
#[inline]
fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
let step_size = self.len().min(n);
let to_drop = ptr::slice_from_raw_parts_mut(self.ptr.as_ptr(), step_size);
if T::IS_ZST {
// See `next` for why we sub `end` here.
self.end = self.end.wrapping_byte_sub(step_size);
} else {
// SAFETY: the min() above ensures that step_size is in bounds
self.ptr = unsafe { self.ptr.add(step_size) };
}
// SAFETY: the min() above ensures that step_size is in bounds
unsafe {
ptr::drop_in_place(to_drop);
}
NonZeroUsize::new(n - step_size).map_or(Ok(()), Err)
}
#[inline]
fn count(self) -> usize {
self.len()
}
#[inline]
fn next_chunk<const N: usize>(&mut self) -> Result<[T; N], core::array::IntoIter<T, N>> {
let mut raw_ary = MaybeUninit::uninit_array();
let len = self.len();
if T::IS_ZST {
if len < N {
self.forget_remaining_elements();
// Safety: ZSTs can be conjured ex nihilo, only the amount has to be correct
return Err(unsafe { array::IntoIter::new_unchecked(raw_ary, 0..len) });
}
self.end = self.end.wrapping_byte_sub(N);
// Safety: ditto
return Ok(unsafe { raw_ary.transpose().assume_init() });
}
if len < N {
// Safety: `len` indicates that this many elements are available and we just checked that
// it fits into the array.
unsafe {
ptr::copy_nonoverlapping(self.ptr.as_ptr(), raw_ary.as_mut_ptr() as *mut T, len);
self.forget_remaining_elements();
return Err(array::IntoIter::new_unchecked(raw_ary, 0..len));
}
}
// Safety: `len` is larger than the array size. Copy a fixed amount here to fully initialize
// the array.
return unsafe {
ptr::copy_nonoverlapping(self.ptr.as_ptr(), raw_ary.as_mut_ptr() as *mut T, N);
self.ptr = self.ptr.add(N);
Ok(raw_ary.transpose().assume_init())
};
}
unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
where
Self: TrustedRandomAccessNoCoerce,
{
// SAFETY: the caller must guarantee that `i` is in bounds of the
// `Vec<T>`, so `i` cannot overflow an `isize`, and the `self.ptr.add(i)`
// is guaranteed to pointer to an element of the `Vec<T>` and
// thus guaranteed to be valid to dereference.
//
// Also note the implementation of `Self: TrustedRandomAccess` requires
// that `T: Copy` so reading elements from the buffer doesn't invalidate
// them for `Drop`.
unsafe { if T::IS_ZST { mem::zeroed() } else { self.ptr.add(i).read() } }
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
#[inline]
fn next_back(&mut self) -> Option<T> {
if T::IS_ZST {
if self.end as *mut _ == self.ptr.as_ptr() {
None
} else {
// See above for why 'ptr.offset' isn't used
self.end = self.end.wrapping_byte_sub(1);
// Make up a value of this ZST.
Some(unsafe { mem::zeroed() })
}
} else {
if non_null!(self.end, T) == self.ptr {
None
} else {
let new_end = unsafe { non_null!(self.end, T).sub(1) };
*non_null!(mut self.end, T) = new_end;
Some(unsafe { ptr::read(new_end.as_ptr()) })
}
}
}
#[inline]
fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
let step_size = self.len().min(n);
if T::IS_ZST {
// SAFETY: same as for advance_by()
self.end = self.end.wrapping_byte_sub(step_size);
} else {
// SAFETY: same as for advance_by()
self.end = unsafe { self.end.sub(step_size) };
}
let to_drop = ptr::slice_from_raw_parts_mut(self.end as *mut T, step_size);
// SAFETY: same as for advance_by()
unsafe {
ptr::drop_in_place(to_drop);
}
NonZeroUsize::new(n - step_size).map_or(Ok(()), Err)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T, A: Allocator> ExactSizeIterator for IntoIter<T, A> {
fn is_empty(&self) -> bool {
if T::IS_ZST {
self.ptr.as_ptr() == self.end as *mut _
} else {
self.ptr == non_null!(self.end, T)
}
}
}
#[stable(feature = "fused", since = "1.26.0")]
impl<T, A: Allocator> FusedIterator for IntoIter<T, A> {}
#[doc(hidden)]
#[unstable(issue = "none", feature = "trusted_fused")]
unsafe impl<T, A: Allocator> TrustedFused for IntoIter<T, A> {}
#[unstable(feature = "trusted_len", issue = "37572")]
unsafe impl<T, A: Allocator> TrustedLen for IntoIter<T, A> {}
#[stable(feature = "default_iters", since = "1.70.0")]
impl<T, A> Default for IntoIter<T, A>
where
A: Allocator + Default,
{
/// Creates an empty `vec::IntoIter`.
///
/// ```
/// # use std::vec;
/// let iter: vec::IntoIter<u8> = Default::default();
/// assert_eq!(iter.len(), 0);
/// assert_eq!(iter.as_slice(), &[]);
/// ```
fn default() -> Self {
super::Vec::new_in(Default::default()).into_iter()
}
}
#[doc(hidden)]
#[unstable(issue = "none", feature = "std_internals")]
#[rustc_unsafe_specialization_marker]
pub trait NonDrop {}
// T: Copy as approximation for !Drop since get_unchecked does not advance self.ptr
// and thus we can't implement drop-handling
#[unstable(issue = "none", feature = "std_internals")]
impl<T: Copy> NonDrop for T {}
#[doc(hidden)]
#[unstable(issue = "none", feature = "std_internals")]
// TrustedRandomAccess (without NoCoerce) must not be implemented because
// subtypes/supertypes of `T` might not be `NonDrop`
unsafe impl<T, A: Allocator> TrustedRandomAccessNoCoerce for IntoIter<T, A>
where
T: NonDrop,
{
const MAY_HAVE_SIDE_EFFECT: bool = false;
}
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
#[cfg(not(test))]
fn clone(&self) -> Self {
self.as_slice().to_vec_in(self.alloc.deref().clone()).into_iter()
}
#[cfg(test)]
fn clone(&self) -> Self {
crate::slice::to_vec(self.as_slice(), self.alloc.deref().clone()).into_iter()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
fn drop(&mut self) {
struct DropGuard<'a, T, A: Allocator>(&'a mut IntoIter<T, A>);
impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
fn drop(&mut self) {
unsafe {
// `IntoIter::alloc` is not used anymore after this and will be dropped by RawVec
let alloc = ManuallyDrop::take(&mut self.0.alloc);
// RawVec handles deallocation
let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
}
}
}
let guard = DropGuard(self);
// destroy the remaining elements
unsafe {
ptr::drop_in_place(guard.0.as_raw_mut_slice());
}
// now `guard` will be dropped and do the rest
}
}
// In addition to the SAFETY invariants of the following three unsafe traits
// also refer to the vec::in_place_collect module documentation to get an overview
#[unstable(issue = "none", feature = "inplace_iteration")]
#[doc(hidden)]
unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {
const EXPAND_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
const MERGE_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
}
#[unstable(issue = "none", feature = "inplace_iteration")]
#[doc(hidden)]
unsafe impl<T, A: Allocator> SourceIter for IntoIter<T, A> {
type Source = Self;
#[inline]
unsafe fn as_inner(&mut self) -> &mut Self::Source {
self
}
}
#[cfg(not(no_global_oom_handling))]
unsafe impl<T> AsVecIntoIter for IntoIter<T> {
type Item = T;
fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
self
}
}

204
rust/alloc/vec/is_zero.rs
View File

@@ -1,204 +0,0 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
use core::num::{Saturating, Wrapping};
use crate::boxed::Box;
#[rustc_specialization_trait]
pub(super) unsafe trait IsZero {
/// Whether this value's representation is all zeros,
/// or can be represented with all zeroes.
fn is_zero(&self) -> bool;
}
macro_rules! impl_is_zero {
($t:ty, $is_zero:expr) => {
unsafe impl IsZero for $t {
#[inline]
fn is_zero(&self) -> bool {
$is_zero(*self)
}
}
};
}
impl_is_zero!(i8, |x| x == 0); // It is needed to impl for arrays and tuples of i8.
impl_is_zero!(i16, |x| x == 0);
impl_is_zero!(i32, |x| x == 0);
impl_is_zero!(i64, |x| x == 0);
impl_is_zero!(i128, |x| x == 0);
impl_is_zero!(isize, |x| x == 0);
impl_is_zero!(u8, |x| x == 0); // It is needed to impl for arrays and tuples of u8.
impl_is_zero!(u16, |x| x == 0);
impl_is_zero!(u32, |x| x == 0);
impl_is_zero!(u64, |x| x == 0);
impl_is_zero!(u128, |x| x == 0);
impl_is_zero!(usize, |x| x == 0);
impl_is_zero!(bool, |x| x == false);
impl_is_zero!(char, |x| x == '\0');
impl_is_zero!(f32, |x: f32| x.to_bits() == 0);
impl_is_zero!(f64, |x: f64| x.to_bits() == 0);
unsafe impl<T> IsZero for *const T {
#[inline]
fn is_zero(&self) -> bool {
(*self).is_null()
}
}
unsafe impl<T> IsZero for *mut T {
#[inline]
fn is_zero(&self) -> bool {
(*self).is_null()
}
}
unsafe impl<T: IsZero, const N: usize> IsZero for [T; N] {
#[inline]
fn is_zero(&self) -> bool {
// Because this is generated as a runtime check, it's not obvious that
// it's worth doing if the array is really long. The threshold here
// is largely arbitrary, but was picked because as of 2022-07-01 LLVM
// fails to const-fold the check in `vec![[1; 32]; n]`
// See https://github.com/rust-lang/rust/pull/97581#issuecomment-1166628022
// Feel free to tweak if you have better evidence.
N <= 16 && self.iter().all(IsZero::is_zero)
}
}
// This is recursive macro.
macro_rules! impl_for_tuples {
// Stopper
() => {
// No use for implementing for empty tuple because it is ZST.
};
($first_arg:ident $(,$rest:ident)*) => {
unsafe impl <$first_arg: IsZero, $($rest: IsZero,)*> IsZero for ($first_arg, $($rest,)*){
#[inline]
fn is_zero(&self) -> bool{
// Destructure tuple to N references
// Rust allows to hide generic params by local variable names.
#[allow(non_snake_case)]
let ($first_arg, $($rest,)*) = self;
$first_arg.is_zero()
$( && $rest.is_zero() )*
}
}
impl_for_tuples!($($rest),*);
}
}
impl_for_tuples!(A, B, C, D, E, F, G, H);
// `Option<&T>` and `Option<Box<T>>` are guaranteed to represent `None` as null.
// For fat pointers, the bytes that would be the pointer metadata in the `Some`
// variant are padding in the `None` variant, so ignoring them and
// zero-initializing instead is ok.
// `Option<&mut T>` never implements `Clone`, so there's no need for an impl of
// `SpecFromElem`.
unsafe impl<T: ?Sized> IsZero for Option<&T> {
#[inline]
fn is_zero(&self) -> bool {
self.is_none()
}
}
unsafe impl<T: ?Sized> IsZero for Option<Box<T>> {
#[inline]
fn is_zero(&self) -> bool {
self.is_none()
}
}
// `Option<num::NonZeroU32>` and similar have a representation guarantee that
// they're the same size as the corresponding `u32` type, as well as a guarantee
// that transmuting between `NonZeroU32` and `Option<num::NonZeroU32>` works.
// While the documentation officially makes it UB to transmute from `None`,
// we're the standard library so we can make extra inferences, and we know that
// the only niche available to represent `None` is the one that's all zeros.
macro_rules! impl_is_zero_option_of_nonzero {
($($t:ident,)+) => {$(
unsafe impl IsZero for Option<core::num::$t> {
#[inline]
fn is_zero(&self) -> bool {
self.is_none()
}
}
)+};
}
impl_is_zero_option_of_nonzero!(
NonZeroU8,
NonZeroU16,
NonZeroU32,
NonZeroU64,
NonZeroU128,
NonZeroI8,
NonZeroI16,
NonZeroI32,
NonZeroI64,
NonZeroI128,
NonZeroUsize,
NonZeroIsize,
);
macro_rules! impl_is_zero_option_of_num {
($($t:ty,)+) => {$(
unsafe impl IsZero for Option<$t> {
#[inline]
fn is_zero(&self) -> bool {
const {
let none: Self = unsafe { core::mem::MaybeUninit::zeroed().assume_init() };
assert!(none.is_none());
}
self.is_none()
}
}
)+};
}
impl_is_zero_option_of_num!(u8, u16, u32, u64, u128, i8, i16, i32, i64, i128, usize, isize,);
unsafe impl<T: IsZero> IsZero for Wrapping<T> {
#[inline]
fn is_zero(&self) -> bool {
self.0.is_zero()
}
}
unsafe impl<T: IsZero> IsZero for Saturating<T> {
#[inline]
fn is_zero(&self) -> bool {
self.0.is_zero()
}
}
macro_rules! impl_for_optional_bool {
($($t:ty,)+) => {$(
unsafe impl IsZero for $t {
#[inline]
fn is_zero(&self) -> bool {
// SAFETY: This is *not* a stable layout guarantee, but
// inside `core` we're allowed to rely on the current rustc
// behaviour that options of bools will be one byte with
// no padding, so long as they're nested less than 254 deep.
let raw: u8 = unsafe { core::mem::transmute(*self) };
raw == 0
}
}
)+};
}
impl_for_optional_bool! {
Option<bool>,
Option<Option<bool>>,
Option<Option<Option<bool>>>,
// Could go further, but not worth the metadata overhead
}

3724
rust/alloc/vec/mod.rs
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49
rust/alloc/vec/partial_eq.rs
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@@ -1,49 +0,0 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
use crate::alloc::Allocator;
#[cfg(not(no_global_oom_handling))]
use crate::borrow::Cow;
use super::Vec;
macro_rules! __impl_slice_eq1 {
([$($vars:tt)*] $lhs:ty, $rhs:ty $(where $ty:ty: $bound:ident)?, #[$stability:meta]) => {
#[$stability]
impl<T, U, $($vars)*> PartialEq<$rhs> for $lhs
where
T: PartialEq<U>,
$($ty: $bound)?
{
#[inline]
fn eq(&self, other: &$rhs) -> bool { self[..] == other[..] }
#[inline]
fn ne(&self, other: &$rhs) -> bool { self[..] != other[..] }
}
}
}
__impl_slice_eq1! { [A1: Allocator, A2: Allocator] Vec<T, A1>, Vec<U, A2>, #[stable(feature = "rust1", since = "1.0.0")] }
__impl_slice_eq1! { [A: Allocator] Vec<T, A>, &[U], #[stable(feature = "rust1", since = "1.0.0")] }
__impl_slice_eq1! { [A: Allocator] Vec<T, A>, &mut [U], #[stable(feature = "rust1", since = "1.0.0")] }
__impl_slice_eq1! { [A: Allocator] &[T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
__impl_slice_eq1! { [A: Allocator] &mut [T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
__impl_slice_eq1! { [A: Allocator] Vec<T, A>, [U], #[stable(feature = "partialeq_vec_for_slice", since = "1.48.0")] }
__impl_slice_eq1! { [A: Allocator] [T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_slice", since = "1.48.0")] }
#[cfg(not(no_global_oom_handling))]
__impl_slice_eq1! { [A: Allocator] Cow<'_, [T]>, Vec<U, A> where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
#[cfg(not(no_global_oom_handling))]
__impl_slice_eq1! { [] Cow<'_, [T]>, &[U] where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
#[cfg(not(no_global_oom_handling))]
__impl_slice_eq1! { [] Cow<'_, [T]>, &mut [U] where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
__impl_slice_eq1! { [A: Allocator, const N: usize] Vec<T, A>, [U; N], #[stable(feature = "rust1", since = "1.0.0")] }
__impl_slice_eq1! { [A: Allocator, const N: usize] Vec<T, A>, &[U; N], #[stable(feature = "rust1", since = "1.0.0")] }
// NOTE: some less important impls are omitted to reduce code bloat
// FIXME(Centril): Reconsider this?
//__impl_slice_eq1! { [const N: usize] Vec<A>, &mut [B; N], }
//__impl_slice_eq1! { [const N: usize] [A; N], Vec<B>, }
//__impl_slice_eq1! { [const N: usize] &[A; N], Vec<B>, }
//__impl_slice_eq1! { [const N: usize] &mut [A; N], Vec<B>, }
//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, [B; N], }
//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &[B; N], }
//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &mut [B; N], }

35
rust/alloc/vec/set_len_on_drop.rs
View File

@@ -1,35 +0,0 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
// Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
//
// The idea is: The length field in SetLenOnDrop is a local variable
// that the optimizer will see does not alias with any stores through the Vec's data
// pointer. This is a workaround for alias analysis issue #32155
pub(super) struct SetLenOnDrop<'a> {
len: &'a mut usize,
local_len: usize,
}
impl<'a> SetLenOnDrop<'a> {
#[inline]
pub(super) fn new(len: &'a mut usize) -> Self {
SetLenOnDrop { local_len: *len, len }
}
#[inline]
pub(super) fn increment_len(&mut self, increment: usize) {
self.local_len += increment;
}
#[inline]
pub(super) fn current_len(&self) -> usize {
self.local_len
}
}
impl Drop for SetLenOnDrop<'_> {
#[inline]
fn drop(&mut self) {
*self.len = self.local_len;
}
}

119
rust/alloc/vec/spec_extend.rs
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@@ -1,119 +0,0 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
use crate::alloc::Allocator;
use crate::collections::TryReserveError;
use core::iter::TrustedLen;
use core::slice::{self};
use super::{IntoIter, Vec};
// Specialization trait used for Vec::extend
#[cfg(not(no_global_oom_handling))]
pub(super) trait SpecExtend<T, I> {
fn spec_extend(&mut self, iter: I);
}
// Specialization trait used for Vec::try_extend
pub(super) trait TrySpecExtend<T, I> {
fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError>;
}
#[cfg(not(no_global_oom_handling))]
impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
where
I: Iterator<Item = T>,
{
default fn spec_extend(&mut self, iter: I) {
self.extend_desugared(iter)
}
}
impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
where
I: Iterator<Item = T>,
{
default fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError> {
self.try_extend_desugared(iter)
}
}
#[cfg(not(no_global_oom_handling))]
impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
where
I: TrustedLen<Item = T>,
{
default fn spec_extend(&mut self, iterator: I) {
self.extend_trusted(iterator)
}
}
impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
where
I: TrustedLen<Item = T>,
{
default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
self.try_extend_trusted(iterator)
}
}
#[cfg(not(no_global_oom_handling))]
impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
unsafe {
self.append_elements(iterator.as_slice() as _);
}
iterator.forget_remaining_elements();
}
}
impl<T, A: Allocator> TrySpecExtend<T, IntoIter<T>> for Vec<T, A> {
fn try_spec_extend(&mut self, mut iterator: IntoIter<T>) -> Result<(), TryReserveError> {
unsafe {
self.try_append_elements(iterator.as_slice() as _)?;
}
iterator.forget_remaining_elements();
Ok(())
}
}
#[cfg(not(no_global_oom_handling))]
impl<'a, T: 'a, I, A: Allocator> SpecExtend<&'a T, I> for Vec<T, A>
where
I: Iterator<Item = &'a T>,
T: Clone,
{
default fn spec_extend(&mut self, iterator: I) {
self.spec_extend(iterator.cloned())
}
}
impl<'a, T: 'a, I, A: Allocator> TrySpecExtend<&'a T, I> for Vec<T, A>
where
I: Iterator<Item = &'a T>,
T: Clone,
{
default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
self.try_spec_extend(iterator.cloned())
}
}
#[cfg(not(no_global_oom_handling))]
impl<'a, T: 'a, A: Allocator> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
where
T: Copy,
{
fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
let slice = iterator.as_slice();
unsafe { self.append_elements(slice) };
}
}
impl<'a, T: 'a, A: Allocator> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
where
T: Copy,
{
fn try_spec_extend(&mut self, iterator: slice::Iter<'a, T>) -> Result<(), TryReserveError> {
let slice = iterator.as_slice();
unsafe { self.try_append_elements(slice) }
}
}