rename RcBox to RcInner for consistency
This commit is contained in:
Jonathan Dönszelmann
parent
d0141af514
commit
159e67d446
@ -282,19 +282,19 @@
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// would interfere with otherwise safe [into|from]_raw() of transmutable
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// inner types.
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#[repr(C)]
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struct RcBox<T: ?Sized> {
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struct RcInner<T: ?Sized> {
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strong: Cell<usize>,
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weak: Cell<usize>,
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value: T,
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}
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/// Calculate layout for `RcBox<T>` using the inner value's layout
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/// Calculate layout for `RcInner<T>` using the inner value's layout
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fn rcbox_layout_for_value_layout(layout: Layout) -> Layout {
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// Calculate layout using the given value layout.
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// Previously, layout was calculated on the expression
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// `&*(ptr as *const RcBox<T>)`, but this created a misaligned
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// `&*(ptr as *const RcInner<T>)`, but this created a misaligned
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// reference (see #54908).
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Layout::new::<RcBox<()>>().extend(layout).unwrap().0.pad_to_align()
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Layout::new::<RcInner<()>>().extend(layout).unwrap().0.pad_to_align()
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}
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/// A single-threaded reference-counting pointer. 'Rc' stands for 'Reference
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@ -314,8 +314,8 @@ pub struct Rc<
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T: ?Sized,
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#[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
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> {
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ptr: NonNull<RcBox<T>>,
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phantom: PhantomData<RcBox<T>>,
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ptr: NonNull<RcInner<T>>,
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phantom: PhantomData<RcInner<T>>,
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alloc: A,
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}
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@ -343,37 +343,37 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Rc<U>> for Rc<T> {}
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impl<T: ?Sized> Rc<T> {
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#[inline]
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unsafe fn from_inner(ptr: NonNull<RcBox<T>>) -> Self {
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unsafe fn from_inner(ptr: NonNull<RcInner<T>>) -> Self {
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unsafe { Self::from_inner_in(ptr, Global) }
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}
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#[inline]
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unsafe fn from_ptr(ptr: *mut RcBox<T>) -> Self {
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unsafe fn from_ptr(ptr: *mut RcInner<T>) -> Self {
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unsafe { Self::from_inner(NonNull::new_unchecked(ptr)) }
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}
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}
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impl<T: ?Sized, A: Allocator> Rc<T, A> {
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#[inline(always)]
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fn inner(&self) -> &RcBox<T> {
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fn inner(&self) -> &RcInner<T> {
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// This unsafety is ok because while this Rc is alive we're guaranteed
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// that the inner pointer is valid.
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unsafe { self.ptr.as_ref() }
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}
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#[inline]
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fn into_inner_with_allocator(this: Self) -> (NonNull<RcBox<T>>, A) {
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fn into_inner_with_allocator(this: Self) -> (NonNull<RcInner<T>>, A) {
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let this = mem::ManuallyDrop::new(this);
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(this.ptr, unsafe { ptr::read(&this.alloc) })
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}
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#[inline]
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unsafe fn from_inner_in(ptr: NonNull<RcBox<T>>, alloc: A) -> Self {
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unsafe fn from_inner_in(ptr: NonNull<RcInner<T>>, alloc: A) -> Self {
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Self { ptr, phantom: PhantomData, alloc }
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}
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#[inline]
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unsafe fn from_ptr_in(ptr: *mut RcBox<T>, alloc: A) -> Self {
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unsafe fn from_ptr_in(ptr: *mut RcInner<T>, alloc: A) -> Self {
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unsafe { Self::from_inner_in(NonNull::new_unchecked(ptr), alloc) }
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}
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}
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@ -397,7 +397,7 @@ pub fn new(value: T) -> Rc<T> {
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// if the weak pointer is stored inside the strong one.
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unsafe {
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Self::from_inner(
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Box::leak(Box::new(RcBox { strong: Cell::new(1), weak: Cell::new(1), value }))
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Box::leak(Box::new(RcInner { strong: Cell::new(1), weak: Cell::new(1), value }))
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.into(),
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)
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}
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@ -546,8 +546,12 @@ pub fn try_new(value: T) -> Result<Rc<T>, AllocError> {
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// if the weak pointer is stored inside the strong one.
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unsafe {
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Ok(Self::from_inner(
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Box::leak(Box::try_new(RcBox { strong: Cell::new(1), weak: Cell::new(1), value })?)
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.into(),
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Box::leak(Box::try_new(RcInner {
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strong: Cell::new(1),
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weak: Cell::new(1),
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value,
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})?)
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.into(),
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))
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}
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}
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@ -646,7 +650,7 @@ pub fn new_in(value: T, alloc: A) -> Rc<T, A> {
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// That would make code size bigger.
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match Self::try_new_in(value, alloc) {
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Ok(m) => m,
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Err(_) => handle_alloc_error(Layout::new::<RcBox<T>>()),
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Err(_) => handle_alloc_error(Layout::new::<RcInner<T>>()),
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}
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}
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@ -765,7 +769,7 @@ pub fn new_cyclic_in<F>(data_fn: F, alloc: A) -> Rc<T, A>
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// Construct the inner in the "uninitialized" state with a single
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// weak reference.
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let (uninit_raw_ptr, alloc) = Box::into_raw_with_allocator(Box::new_in(
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RcBox {
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RcInner {
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strong: Cell::new(0),
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weak: Cell::new(1),
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value: mem::MaybeUninit::<T>::uninit(),
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@ -773,7 +777,7 @@ pub fn new_cyclic_in<F>(data_fn: F, alloc: A) -> Rc<T, A>
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alloc,
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));
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let uninit_ptr: NonNull<_> = (unsafe { &mut *uninit_raw_ptr }).into();
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let init_ptr: NonNull<RcBox<T>> = uninit_ptr.cast();
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let init_ptr: NonNull<RcInner<T>> = uninit_ptr.cast();
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let weak = Weak { ptr: init_ptr, alloc: alloc };
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@ -826,7 +830,7 @@ pub fn try_new_in(value: T, alloc: A) -> Result<Self, AllocError> {
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// the allocation while the strong destructor is running, even
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// if the weak pointer is stored inside the strong one.
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let (ptr, alloc) = Box::into_unique(Box::try_new_in(
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RcBox { strong: Cell::new(1), weak: Cell::new(1), value },
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RcInner { strong: Cell::new(1), weak: Cell::new(1), value },
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alloc,
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)?);
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Ok(unsafe { Self::from_inner_in(ptr.into(), alloc) })
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@ -1059,7 +1063,7 @@ pub fn new_zeroed_slice(len: usize) -> Rc<[mem::MaybeUninit<T>]> {
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|layout| Global.allocate_zeroed(layout),
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|mem| {
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ptr::slice_from_raw_parts_mut(mem.cast::<T>(), len)
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as *mut RcBox<[mem::MaybeUninit<T>]>
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as *mut RcInner<[mem::MaybeUninit<T>]>
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},
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))
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}
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@ -1132,7 +1136,7 @@ pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Rc<[mem::MaybeUninit<T>], A>
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|layout| alloc.allocate_zeroed(layout),
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|mem| {
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ptr::slice_from_raw_parts_mut(mem.cast::<T>(), len)
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as *mut RcBox<[mem::MaybeUninit<T>]>
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as *mut RcInner<[mem::MaybeUninit<T>]>
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},
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),
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alloc,
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@ -1437,7 +1441,7 @@ pub fn into_raw_with_allocator(this: Self) -> (*const T, A) {
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#[stable(feature = "weak_into_raw", since = "1.45.0")]
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#[rustc_never_returns_null_ptr]
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pub fn as_ptr(this: &Self) -> *const T {
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let ptr: *mut RcBox<T> = NonNull::as_ptr(this.ptr);
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let ptr: *mut RcInner<T> = NonNull::as_ptr(this.ptr);
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// SAFETY: This cannot go through Deref::deref or Rc::inner because
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// this is required to retain raw/mut provenance such that e.g. `get_mut` can
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@ -1516,8 +1520,8 @@ pub fn as_ptr(this: &Self) -> *const T {
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pub unsafe fn from_raw_in(ptr: *const T, alloc: A) -> Self {
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let offset = unsafe { data_offset(ptr) };
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// Reverse the offset to find the original RcBox.
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let rc_ptr = unsafe { ptr.byte_sub(offset) as *mut RcBox<T> };
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// Reverse the offset to find the original RcInner.
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let rc_ptr = unsafe { ptr.byte_sub(offset) as *mut RcInner<T> };
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unsafe { Self::from_ptr_in(rc_ptr, alloc) }
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}
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@ -2002,17 +2006,17 @@ pub unsafe fn downcast_unchecked<T: Any>(self) -> Rc<T, A> {
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}
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impl<T: ?Sized> Rc<T> {
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/// Allocates an `RcBox<T>` with sufficient space for
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/// Allocates an `RcInner<T>` with sufficient space for
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/// a possibly-unsized inner value where the value has the layout provided.
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///
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/// The function `mem_to_rcbox` is called with the data pointer
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/// and must return back a (potentially fat)-pointer for the `RcBox<T>`.
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/// and must return back a (potentially fat)-pointer for the `RcInner<T>`.
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#[cfg(not(no_global_oom_handling))]
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unsafe fn allocate_for_layout(
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value_layout: Layout,
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allocate: impl FnOnce(Layout) -> Result<NonNull<[u8]>, AllocError>,
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mem_to_rcbox: impl FnOnce(*mut u8) -> *mut RcBox<T>,
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) -> *mut RcBox<T> {
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mem_to_rcbox: impl FnOnce(*mut u8) -> *mut RcInner<T>,
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) -> *mut RcInner<T> {
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let layout = rcbox_layout_for_value_layout(value_layout);
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unsafe {
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Rc::try_allocate_for_layout(value_layout, allocate, mem_to_rcbox)
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@ -2020,24 +2024,24 @@ unsafe fn allocate_for_layout(
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}
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}
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/// Allocates an `RcBox<T>` with sufficient space for
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/// Allocates an `RcInner<T>` with sufficient space for
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/// a possibly-unsized inner value where the value has the layout provided,
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/// returning an error if allocation fails.
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///
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/// The function `mem_to_rcbox` is called with the data pointer
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/// and must return back a (potentially fat)-pointer for the `RcBox<T>`.
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/// and must return back a (potentially fat)-pointer for the `RcInner<T>`.
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#[inline]
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unsafe fn try_allocate_for_layout(
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value_layout: Layout,
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allocate: impl FnOnce(Layout) -> Result<NonNull<[u8]>, AllocError>,
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mem_to_rcbox: impl FnOnce(*mut u8) -> *mut RcBox<T>,
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) -> Result<*mut RcBox<T>, AllocError> {
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mem_to_rcbox: impl FnOnce(*mut u8) -> *mut RcInner<T>,
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) -> Result<*mut RcInner<T>, AllocError> {
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let layout = rcbox_layout_for_value_layout(value_layout);
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// Allocate for the layout.
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let ptr = allocate(layout)?;
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// Initialize the RcBox
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// Initialize the RcInner
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let inner = mem_to_rcbox(ptr.as_non_null_ptr().as_ptr());
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unsafe {
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debug_assert_eq!(Layout::for_value_raw(inner), layout);
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@ -2051,15 +2055,15 @@ unsafe fn try_allocate_for_layout(
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}
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impl<T: ?Sized, A: Allocator> Rc<T, A> {
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/// Allocates an `RcBox<T>` with sufficient space for an unsized inner value
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/// Allocates an `RcInner<T>` with sufficient space for an unsized inner value
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#[cfg(not(no_global_oom_handling))]
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unsafe fn allocate_for_ptr_in(ptr: *const T, alloc: &A) -> *mut RcBox<T> {
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// Allocate for the `RcBox<T>` using the given value.
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unsafe fn allocate_for_ptr_in(ptr: *const T, alloc: &A) -> *mut RcInner<T> {
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// Allocate for the `RcInner<T>` using the given value.
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unsafe {
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Rc::<T>::allocate_for_layout(
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Layout::for_value_raw(ptr),
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|layout| alloc.allocate(layout),
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|mem| mem.with_metadata_of(ptr as *const RcBox<T>),
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|mem| mem.with_metadata_of(ptr as *const RcInner<T>),
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)
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}
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}
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@ -2088,14 +2092,14 @@ fn from_box_in(src: Box<T, A>) -> Rc<T, A> {
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}
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impl<T> Rc<[T]> {
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/// Allocates an `RcBox<[T]>` with the given length.
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/// Allocates an `RcInner<[T]>` with the given length.
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#[cfg(not(no_global_oom_handling))]
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unsafe fn allocate_for_slice(len: usize) -> *mut RcBox<[T]> {
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unsafe fn allocate_for_slice(len: usize) -> *mut RcInner<[T]> {
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unsafe {
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Self::allocate_for_layout(
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Layout::array::<T>(len).unwrap(),
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|layout| Global.allocate(layout),
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|mem| ptr::slice_from_raw_parts_mut(mem.cast::<T>(), len) as *mut RcBox<[T]>,
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|mem| ptr::slice_from_raw_parts_mut(mem.cast::<T>(), len) as *mut RcInner<[T]>,
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)
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}
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}
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@ -2119,7 +2123,7 @@ unsafe fn copy_from_slice(v: &[T]) -> Rc<[T]> {
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unsafe fn from_iter_exact(iter: impl Iterator<Item = T>, len: usize) -> Rc<[T]> {
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// Panic guard while cloning T elements.
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// In the event of a panic, elements that have been written
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// into the new RcBox will be dropped, then the memory freed.
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// into the new RcInner will be dropped, then the memory freed.
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struct Guard<T> {
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mem: NonNull<u8>,
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elems: *mut T,
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@ -2154,7 +2158,7 @@ fn drop(&mut self) {
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guard.n_elems += 1;
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}
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// All clear. Forget the guard so it doesn't free the new RcBox.
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// All clear. Forget the guard so it doesn't free the new RcInner.
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mem::forget(guard);
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Self::from_ptr(ptr)
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@ -2163,15 +2167,15 @@ fn drop(&mut self) {
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}
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impl<T, A: Allocator> Rc<[T], A> {
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/// Allocates an `RcBox<[T]>` with the given length.
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/// Allocates an `RcInner<[T]>` with the given length.
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#[inline]
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#[cfg(not(no_global_oom_handling))]
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unsafe fn allocate_for_slice_in(len: usize, alloc: &A) -> *mut RcBox<[T]> {
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unsafe fn allocate_for_slice_in(len: usize, alloc: &A) -> *mut RcInner<[T]> {
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unsafe {
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Rc::<[T]>::allocate_for_layout(
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Layout::array::<T>(len).unwrap(),
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|layout| alloc.allocate(layout),
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|mem| ptr::slice_from_raw_parts_mut(mem.cast::<T>(), len) as *mut RcBox<[T]>,
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|mem| ptr::slice_from_raw_parts_mut(mem.cast::<T>(), len) as *mut RcInner<[T]>,
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)
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}
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}
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@ -2901,9 +2905,9 @@ pub struct Weak<
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// but it is not necessarily a valid pointer.
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// `Weak::new` sets this to `usize::MAX` so that it doesn’t need
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// to allocate space on the heap. That's not a value a real pointer
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// will ever have because RcBox has alignment at least 2.
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// will ever have because RcInner has alignment at least 2.
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// This is only possible when `T: Sized`; unsized `T` never dangle.
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ptr: NonNull<RcBox<T>>,
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ptr: NonNull<RcInner<T>>,
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alloc: A,
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}
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@ -2939,7 +2943,7 @@ impl<T> Weak<T> {
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pub const fn new() -> Weak<T> {
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Weak {
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ptr: unsafe {
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NonNull::new_unchecked(ptr::without_provenance_mut::<RcBox<T>>(usize::MAX))
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NonNull::new_unchecked(ptr::without_provenance_mut::<RcInner<T>>(usize::MAX))
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},
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alloc: Global,
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}
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@ -2966,7 +2970,7 @@ impl<T, A: Allocator> Weak<T, A> {
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pub fn new_in(alloc: A) -> Weak<T, A> {
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Weak {
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ptr: unsafe {
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NonNull::new_unchecked(ptr::without_provenance_mut::<RcBox<T>>(usize::MAX))
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NonNull::new_unchecked(ptr::without_provenance_mut::<RcInner<T>>(usize::MAX))
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},
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alloc,
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}
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@ -3070,11 +3074,11 @@ pub fn allocator(&self) -> &A {
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#[must_use]
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#[stable(feature = "rc_as_ptr", since = "1.45.0")]
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pub fn as_ptr(&self) -> *const T {
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let ptr: *mut RcBox<T> = NonNull::as_ptr(self.ptr);
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let ptr: *mut RcInner<T> = NonNull::as_ptr(self.ptr);
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if is_dangling(ptr) {
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// If the pointer is dangling, we return the sentinel directly. This cannot be
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// a valid payload address, as the payload is at least as aligned as RcBox (usize).
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// a valid payload address, as the payload is at least as aligned as RcInner (usize).
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ptr as *const T
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} else {
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// SAFETY: if is_dangling returns false, then the pointer is dereferenceable.
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@ -3206,14 +3210,14 @@ pub unsafe fn from_raw_in(ptr: *const T, alloc: A) -> Self {
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let ptr = if is_dangling(ptr) {
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// This is a dangling Weak.
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ptr as *mut RcBox<T>
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ptr as *mut RcInner<T>
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} else {
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// Otherwise, we're guaranteed the pointer came from a nondangling Weak.
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// SAFETY: data_offset is safe to call, as ptr references a real (potentially dropped) T.
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let offset = unsafe { data_offset(ptr) };
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// Thus, we reverse the offset to get the whole RcBox.
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// Thus, we reverse the offset to get the whole RcInner.
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// SAFETY: the pointer originated from a Weak, so this offset is safe.
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unsafe { ptr.byte_sub(offset) as *mut RcBox<T> }
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unsafe { ptr.byte_sub(offset) as *mut RcInner<T> }
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};
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// SAFETY: we now have recovered the original Weak pointer, so can create the Weak.
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@ -3288,7 +3292,7 @@ pub fn weak_count(&self) -> usize {
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}
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}
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/// Returns `None` when the pointer is dangling and there is no allocated `RcBox`,
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/// Returns `None` when the pointer is dangling and there is no allocated `RcInner`,
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/// (i.e., when this `Weak` was created by `Weak::new`).
|
||||
#[inline]
|
||||
fn inner(&self) -> Option<WeakInner<'_>> {
|
||||
@ -3522,7 +3526,7 @@ fn dec_weak(&self) {
|
||||
}
|
||||
}
|
||||
|
||||
impl<T: ?Sized> RcInnerPtr for RcBox<T> {
|
||||
impl<T: ?Sized> RcInnerPtr for RcInner<T> {
|
||||
#[inline(always)]
|
||||
fn weak_ref(&self) -> &Cell<usize> {
|
||||
&self.weak
|
||||
@ -3563,15 +3567,15 @@ fn as_ref(&self) -> &T {
|
||||
#[stable(feature = "pin", since = "1.33.0")]
|
||||
impl<T: ?Sized, A: Allocator> Unpin for Rc<T, A> {}
|
||||
|
||||
/// Gets the offset within an `RcBox` for the payload behind a pointer.
|
||||
/// Gets the offset within an `RcInner` for the payload behind a pointer.
|
||||
///
|
||||
/// # Safety
|
||||
///
|
||||
/// The pointer must point to (and have valid metadata for) a previously
|
||||
/// valid instance of T, but the T is allowed to be dropped.
|
||||
unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> usize {
|
||||
// Align the unsized value to the end of the RcBox.
|
||||
// Because RcBox is repr(C), it will always be the last field in memory.
|
||||
// Align the unsized value to the end of the RcInner.
|
||||
// Because RcInner is repr(C), it will always be the last field in memory.
|
||||
// SAFETY: since the only unsized types possible are slices, trait objects,
|
||||
// and extern types, the input safety requirement is currently enough to
|
||||
// satisfy the requirements of align_of_val_raw; this is an implementation
|
||||
@ -3581,7 +3585,7 @@ unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> usize {
|
||||
|
||||
#[inline]
|
||||
fn data_offset_align(align: usize) -> usize {
|
||||
let layout = Layout::new::<RcBox<()>>();
|
||||
let layout = Layout::new::<RcInner<()>>();
|
||||
layout.size() + layout.padding_needed_for(align)
|
||||
}
|
||||
|
||||
@ -3627,8 +3631,8 @@ pub struct UniqueRc<
|
||||
T: ?Sized,
|
||||
#[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
|
||||
> {
|
||||
ptr: NonNull<RcBox<T>>,
|
||||
phantom: PhantomData<RcBox<T>>,
|
||||
ptr: NonNull<RcInner<T>>,
|
||||
phantom: PhantomData<RcInner<T>>,
|
||||
alloc: A,
|
||||
}
|
||||
|
||||
@ -3664,7 +3668,7 @@ impl<T, A: Allocator> UniqueRc<T, A> {
|
||||
#[unstable(feature = "unique_rc_arc", issue = "112566")]
|
||||
pub fn new_in(value: T, alloc: A) -> Self {
|
||||
let (ptr, alloc) = Box::into_unique(Box::new_in(
|
||||
RcBox {
|
||||
RcInner {
|
||||
strong: Cell::new(0),
|
||||
// keep one weak reference so if all the weak pointers that are created are dropped
|
||||
// the UniqueRc still stays valid.
|
||||
@ -3759,7 +3763,7 @@ fn drop(&mut self) {
|
||||
}
|
||||
}
|
||||
|
||||
/// A unique owning pointer to a [`RcBox`] **that does not imply the contents are initialized,**
|
||||
/// A unique owning pointer to a [`RcInner`] **that does not imply the contents are initialized,**
|
||||
/// but will deallocate it (without dropping the value) when dropped.
|
||||
///
|
||||
/// This is a helper for [`Rc::make_mut()`] to ensure correct cleanup on panic.
|
||||
@ -3767,21 +3771,21 @@ fn drop(&mut self) {
|
||||
/// which `MaybeUninit` does not.
|
||||
#[cfg(not(no_global_oom_handling))]
|
||||
struct UniqueRcUninit<T: ?Sized, A: Allocator> {
|
||||
ptr: NonNull<RcBox<T>>,
|
||||
ptr: NonNull<RcInner<T>>,
|
||||
layout_for_value: Layout,
|
||||
alloc: Option<A>,
|
||||
}
|
||||
|
||||
#[cfg(not(no_global_oom_handling))]
|
||||
impl<T: ?Sized, A: Allocator> UniqueRcUninit<T, A> {
|
||||
/// Allocates a RcBox with layout suitable to contain `for_value` or a clone of it.
|
||||
/// Allocates a RcInner with layout suitable to contain `for_value` or a clone of it.
|
||||
fn new(for_value: &T, alloc: A) -> UniqueRcUninit<T, A> {
|
||||
let layout = Layout::for_value(for_value);
|
||||
let ptr = unsafe {
|
||||
Rc::allocate_for_layout(
|
||||
layout,
|
||||
|layout_for_rcbox| alloc.allocate(layout_for_rcbox),
|
||||
|mem| mem.with_metadata_of(ptr::from_ref(for_value) as *const RcBox<T>),
|
||||
|mem| mem.with_metadata_of(ptr::from_ref(for_value) as *const RcInner<T>),
|
||||
)
|
||||
};
|
||||
Self { ptr: NonNull::new(ptr).unwrap(), layout_for_value: layout, alloc: Some(alloc) }
|
||||
|
||||
Loading…
Reference in New Issue
Block a user