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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
//! `Arc<[T]>` slice allocation helpers on [`Arena`].
//!
//! Public docs live on [`Arena`] itself.
use allocator_api2::alloc::{AllocError, Allocator};
use super::{Arena, expect_alloc};
use crate::arc::Arc;
impl<A: Allocator + Clone> Arena<A> {
/// Copy `slice` into a `Shared`-flavor chunk and return an [`Arc`].
///
/// The returned [`Arc`] is safe for cross-thread sharing.
///
/// # Panics
///
/// Panics if the underlying allocator fails or if the `align_of::<T>()` is at least 32 KiB.
/// Use [`Self::try_alloc_slice_copy_arc`] for a fallible variant.
#[inline]
pub fn alloc_slice_copy_arc<T: Copy + Send + Sync>(&self, slice: impl AsRef<[T]>) -> Arc<[T], A>
where
A: Send + Sync,
{
let slice = slice.as_ref();
let ptr = expect_alloc(self.try_alloc_slice_shared_copy::<_, true>(slice));
// SAFETY: helper initialized the slice and accounted for this Arc.
let owned = unsafe { crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr) };
Arc::from_owned_in_chunk(owned)
}
/// Fallible variant of [`Self::alloc_slice_copy_arc`].
///
/// Returns Err([`AllocError`]) instead of panicking if the backing
/// allocator fails.
///
/// # Errors
///
/// Returns [`AllocError`] if the backing allocator fails or if the data alignment
/// is at least 32 KiB.
#[inline]
pub fn try_alloc_slice_copy_arc<T: Copy + Send + Sync>(&self, slice: impl AsRef<[T]>) -> Result<Arc<[T], A>, AllocError>
where
A: Send + Sync,
{
let slice = slice.as_ref();
let ptr = self.try_alloc_slice_shared_copy::<_, false>(slice)?;
// SAFETY: helper initialized the slice and accounted for this Arc;
// OwnedInSharedChunk records both invariants for the safe Arc constructor.
let owned = unsafe { crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr) };
Ok(Arc::from_owned_in_chunk(owned))
}
/// Clone every element of `slice` into a `Shared`-flavor chunk and return an [`Arc`].
///
/// The returned [`Arc`] is safe for cross-thread sharing.
///
/// # Panics
///
/// Panics if the underlying allocator fails or if the `align_of::<T>()` is at least 32 KiB.
/// Use [`Self::try_alloc_slice_clone_arc`] for a fallible variant.
///
/// May panic if `T::clone` panics; already-cloned elements are dropped before the
/// panic propagates.
#[inline]
pub fn alloc_slice_clone_arc<T: Clone + Send + Sync>(&self, slice: impl AsRef<[T]>) -> Arc<[T], A>
where
A: Send + Sync,
{
let ptr = expect_alloc(self.try_alloc_slice_shared_clone_inner::<_, true>(slice.as_ref()));
// SAFETY: helper initialized the slice and accounted for this Arc.
Arc::from_owned_in_chunk(unsafe { crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr) })
}
/// Fallible variant of [`Self::alloc_slice_clone_arc`].
///
/// # Errors
///
/// Returns [`AllocError`] if the backing allocator fails or if the data alignment
/// is at least 32 KiB.
///
/// # Panics
///
/// May panic if `T::clone` panics; already-cloned elements are
/// dropped before the panic propagates.
#[inline]
pub fn try_alloc_slice_clone_arc<T: Clone + Send + Sync>(&self, slice: impl AsRef<[T]>) -> Result<Arc<[T], A>, AllocError>
where
A: Send + Sync,
{
let ptr = self.try_alloc_slice_shared_clone_inner::<_, false>(slice.as_ref())?;
// SAFETY: helper initialized the slice and accounted for this Arc.
Ok(Arc::from_owned_in_chunk(unsafe {
crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr)
}))
}
/// Allocate a slice of `len` elements in a `Shared`-flavor chunk via `f(i)`.
///
/// Element `i` is produced by `f(i)`. The returned [`Arc`] is safe
/// for cross-thread sharing.
///
/// # Panics
///
/// Panics if the underlying allocator fails or if the `align_of::<T>()` is at least 32 KiB.
/// Use [`Self::try_alloc_slice_fill_with_arc`] for a fallible variant.
///
/// If `f` panics, already-initialized elements are dropped (drop guard) and the
/// panic propagates.
#[inline]
pub fn alloc_slice_fill_with_arc<T, F>(&self, len: usize, f: F) -> Arc<[T], A>
where
T: Send + Sync,
F: FnMut(usize) -> T,
A: Send + Sync,
{
let ptr = expect_alloc(self.try_alloc_slice_shared_fill_with_inner::<_, _, true>(len, f));
// SAFETY: helper initialized the slice and accounted for this Arc.
Arc::from_owned_in_chunk(unsafe { crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr) })
}
/// Fallible variant of [`Self::alloc_slice_fill_with_arc`].
///
/// # Errors
///
/// Returns [`AllocError`] if the backing allocator fails or if the data alignment
/// is at least 32 KiB.
///
/// # Panics
///
/// If `f` panics, already-initialized elements are dropped and the
/// panic propagates.
#[inline]
pub fn try_alloc_slice_fill_with_arc<T, F>(&self, len: usize, f: F) -> Result<Arc<[T], A>, AllocError>
where
T: Send + Sync,
F: FnMut(usize) -> T,
A: Send + Sync,
{
let ptr = self.try_alloc_slice_shared_fill_with_inner::<_, _, false>(len, f)?;
// SAFETY: helper initialized the slice and accounted for this Arc.
Ok(Arc::from_owned_in_chunk(unsafe {
crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr)
}))
}
/// Allocate a slice in a `Shared`-flavor chunk and fill it from `iter`.
///
/// Returns an [`Arc`] safe for cross-thread sharing.
///
/// # Panics
///
/// Panics if the backing allocator fails or if the data alignment is at least 32 KiB.
/// Use [`Self::try_alloc_slice_fill_iter_arc`] for a fallible variant.
///
/// May also panic if the iterator yields fewer elements than its
/// `ExactSizeIterator::len()` reported.
#[inline]
pub fn alloc_slice_fill_iter_arc<T, I>(&self, iter: I) -> Arc<[T], A>
where
T: Send + Sync,
I: IntoIterator<Item = T>,
I::IntoIter: ExactSizeIterator,
A: Send + Sync,
{
let ptr = expect_alloc(self.try_alloc_slice_shared_fill_iter_inner::<_, _, true>(iter));
// SAFETY: helper initialized the slice and accounted for this Arc.
Arc::from_owned_in_chunk(unsafe { crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr) })
}
/// Fallible variant of [`Self::alloc_slice_fill_iter_arc`].
///
/// # Errors
///
/// Returns [`AllocError`] if the backing allocator fails or if the data alignment
/// is at least 32 KiB.
///
/// # Panics
///
/// Panics if the iterator yields fewer elements than its
/// `ExactSizeIterator::len()` reported.
#[inline]
pub fn try_alloc_slice_fill_iter_arc<T, I>(&self, iter: I) -> Result<Arc<[T], A>, AllocError>
where
T: Send + Sync,
I: IntoIterator<Item = T>,
I::IntoIter: ExactSizeIterator,
A: Send + Sync,
{
let ptr = self.try_alloc_slice_shared_fill_iter_inner::<_, _, false>(iter)?;
// SAFETY: helper initialized the slice and accounted for this Arc.
Ok(Arc::from_owned_in_chunk(unsafe {
crate::internal::owned_in_chunk::OwnedInSharedChunk::from_raw_alloc(ptr)
}))
}
}
impl<A: Allocator + Clone> Arena<A> {
/// Allocate `len` slots and fill each via `f(i)`, returning a
/// [`Pin<Arc<[T], A>>`](core::pin::Pin). Pin is preserved across
/// `Arc::clone` and across threads.
///
/// # Panics
///
/// See [`Self::alloc_slice_fill_with_arc`].
#[must_use]
#[inline]
pub fn alloc_slice_fill_with_arc_pin<T, F>(&self, len: usize, f: F) -> core::pin::Pin<Arc<[T], A>>
where
T: Send + Sync,
F: FnMut(usize) -> T,
A: Send + Sync + 'static,
{
crate::arc::Arc::into_pin(self.alloc_slice_fill_with_arc(len, f))
}
/// Fallible variant of [`Self::alloc_slice_fill_with_arc_pin`].
///
/// # Errors
///
/// See [`Self::try_alloc_slice_fill_with_arc`].
#[inline]
pub fn try_alloc_slice_fill_with_arc_pin<T, F>(&self, len: usize, f: F) -> Result<core::pin::Pin<Arc<[T], A>>, AllocError>
where
T: Send + Sync,
F: FnMut(usize) -> T,
A: Send + Sync + 'static,
{
self.try_alloc_slice_fill_with_arc(len, f).map(crate::arc::Arc::into_pin)
}
}