Auto merge of #75657 - TimDiekmann:allocref-cleanup, r=Amanieu
Clean up AllocRef implementation and documentation r? @Amanieu
This commit is contained in:
commit
be97d13ffc
3 changed files with 183 additions and 178 deletions
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@ -161,30 +161,69 @@ pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
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unsafe { __rust_alloc_zeroed(layout.size(), layout.align()) }
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unsafe { __rust_alloc_zeroed(layout.size(), layout.align()) }
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}
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}
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impl Global {
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#[inline]
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fn alloc_impl(&mut self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocErr> {
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match layout.size() {
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0 => Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0)),
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// SAFETY: `layout` is non-zero in size,
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size => unsafe {
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let raw_ptr = if zeroed { alloc_zeroed(layout) } else { alloc(layout) };
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let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
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Ok(NonNull::slice_from_raw_parts(ptr, size))
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},
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}
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}
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// Safety: Same as `AllocRef::grow`
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#[inline]
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unsafe fn grow_impl(
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&mut self,
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ptr: NonNull<u8>,
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layout: Layout,
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new_size: usize,
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zeroed: bool,
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) -> Result<NonNull<[u8]>, AllocErr> {
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debug_assert!(
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new_size >= layout.size(),
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"`new_size` must be greater than or equal to `layout.size()`"
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);
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match layout.size() {
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// SAFETY: the caller must ensure that the `new_size` does not overflow.
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// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
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0 => unsafe {
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let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
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self.alloc_impl(new_layout, zeroed)
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},
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// SAFETY: `new_size` is non-zero as `old_size` is greater than or equal to `new_size`
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// as required by safety conditions. Other conditions must be upheld by the caller
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old_size => unsafe {
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// `realloc` probably checks for `new_size >= size` or something similar.
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intrinsics::assume(new_size >= layout.size());
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let raw_ptr = realloc(ptr.as_ptr(), layout, new_size);
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let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
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if zeroed {
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raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
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}
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Ok(NonNull::slice_from_raw_parts(ptr, new_size))
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},
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}
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}
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}
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#[unstable(feature = "allocator_api", issue = "32838")]
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#[unstable(feature = "allocator_api", issue = "32838")]
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unsafe impl AllocRef for Global {
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unsafe impl AllocRef for Global {
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#[inline]
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#[inline]
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fn alloc(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
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fn alloc(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
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let size = layout.size();
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self.alloc_impl(layout, false)
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let ptr = if size == 0 {
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layout.dangling()
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} else {
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// SAFETY: `layout` is non-zero in size,
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unsafe { NonNull::new(alloc(layout)).ok_or(AllocErr)? }
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};
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Ok(NonNull::slice_from_raw_parts(ptr, size))
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}
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}
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#[inline]
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#[inline]
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fn alloc_zeroed(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
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fn alloc_zeroed(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
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let size = layout.size();
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self.alloc_impl(layout, true)
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let ptr = if size == 0 {
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layout.dangling()
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} else {
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// SAFETY: `layout` is non-zero in size,
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unsafe { NonNull::new(alloc_zeroed(layout)).ok_or(AllocErr)? }
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};
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Ok(NonNull::slice_from_raw_parts(ptr, size))
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}
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}
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#[inline]
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#[inline]
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@ -203,26 +242,8 @@ unsafe impl AllocRef for Global {
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layout: Layout,
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layout: Layout,
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new_size: usize,
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new_size: usize,
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) -> Result<NonNull<[u8]>, AllocErr> {
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) -> Result<NonNull<[u8]>, AllocErr> {
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debug_assert!(
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// SAFETY: all conditions must be upheld by the caller
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new_size >= layout.size(),
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unsafe { self.grow_impl(ptr, layout, new_size, false) }
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"`new_size` must be greater than or equal to `layout.size()`"
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);
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// SAFETY: `new_size` must be non-zero, which is checked in the match expression.
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// If `new_size` is zero, then `old_size` has to be zero as well.
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// Other conditions must be upheld by the caller
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unsafe {
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match layout.size() {
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0 => self.alloc(Layout::from_size_align_unchecked(new_size, layout.align())),
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old_size => {
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// `realloc` probably checks for `new_size >= size` or something similar.
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intrinsics::assume(new_size >= old_size);
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let raw_ptr = realloc(ptr.as_ptr(), layout, new_size);
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let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
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Ok(NonNull::slice_from_raw_parts(ptr, new_size))
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}
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}
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}
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}
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}
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#[inline]
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#[inline]
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@ -232,27 +253,8 @@ unsafe impl AllocRef for Global {
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layout: Layout,
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layout: Layout,
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new_size: usize,
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new_size: usize,
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) -> Result<NonNull<[u8]>, AllocErr> {
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) -> Result<NonNull<[u8]>, AllocErr> {
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debug_assert!(
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// SAFETY: all conditions must be upheld by the caller
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new_size >= layout.size(),
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unsafe { self.grow_impl(ptr, layout, new_size, true) }
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"`new_size` must be greater than or equal to `layout.size()`"
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);
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// SAFETY: `new_size` must be non-zero, which is checked in the match expression.
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// If `new_size` is zero, then `old_size` has to be zero as well.
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// Other conditions must be upheld by the caller
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unsafe {
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match layout.size() {
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0 => self.alloc_zeroed(Layout::from_size_align_unchecked(new_size, layout.align())),
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old_size => {
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// `realloc` probably checks for `new_size >= size` or something similar.
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intrinsics::assume(new_size >= old_size);
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let raw_ptr = realloc(ptr.as_ptr(), layout, new_size);
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raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
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let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
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Ok(NonNull::slice_from_raw_parts(ptr, new_size))
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}
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}
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}
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}
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}
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#[inline]
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#[inline]
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@ -262,30 +264,28 @@ unsafe impl AllocRef for Global {
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layout: Layout,
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layout: Layout,
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new_size: usize,
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new_size: usize,
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) -> Result<NonNull<[u8]>, AllocErr> {
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) -> Result<NonNull<[u8]>, AllocErr> {
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let old_size = layout.size();
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debug_assert!(
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debug_assert!(
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new_size <= old_size,
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new_size <= layout.size(),
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"`new_size` must be smaller than or equal to `layout.size()`"
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"`new_size` must be smaller than or equal to `layout.size()`"
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);
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);
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let ptr = if new_size == 0 {
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match new_size {
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// SAFETY: conditions must be upheld by the caller
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// SAFETY: conditions must be upheld by the caller
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unsafe {
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0 => unsafe {
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self.dealloc(ptr, layout);
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self.dealloc(ptr, layout);
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}
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Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0))
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layout.dangling()
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},
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} else {
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// SAFETY: new_size is not zero,
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// Other conditions must be upheld by the caller
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let raw_ptr = unsafe {
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// `realloc` probably checks for `new_size <= old_size` or something similar.
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intrinsics::assume(new_size <= old_size);
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realloc(ptr.as_ptr(), layout, new_size)
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};
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NonNull::new(raw_ptr).ok_or(AllocErr)?
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};
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Ok(NonNull::slice_from_raw_parts(ptr, new_size))
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// SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
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new_size => unsafe {
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// `realloc` probably checks for `new_size <= size` or something similar.
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intrinsics::assume(new_size <= layout.size());
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let raw_ptr = realloc(ptr.as_ptr(), layout, new_size);
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let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
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Ok(NonNull::slice_from_raw_parts(ptr, new_size))
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},
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}
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}
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}
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}
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}
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@ -151,6 +151,11 @@ pub unsafe trait AllocRef {
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/// alignment and a size given by `new_size`. To accomplish this, the allocator may extend the
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/// alignment and a size given by `new_size`. To accomplish this, the allocator may extend the
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/// allocation referenced by `ptr` to fit the new layout.
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/// allocation referenced by `ptr` to fit the new layout.
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///
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///
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/// If this returns `Ok`, then ownership of the memory block referenced by `ptr` has been
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/// transferred to this allocator. The memory may or may not have been freed, and should be
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/// considered unusable unless it was transferred back to the caller again via the return value
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/// of this method.
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///
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/// If this method returns `Err`, then ownership of the memory block has not been transferred to
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/// If this method returns `Err`, then ownership of the memory block has not been transferred to
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/// this allocator, and the contents of the memory block are unaltered.
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/// this allocator, and the contents of the memory block are unaltered.
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///
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///
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@ -192,12 +197,9 @@ pub unsafe trait AllocRef {
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"`new_size` must be greater than or equal to `layout.size()`"
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"`new_size` must be greater than or equal to `layout.size()`"
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);
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);
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let new_layout =
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// SAFETY: the caller must ensure that the `new_size` does not overflow.
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// SAFETY: the caller must ensure that the `new_size` does not overflow.
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// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
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// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
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let new_layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
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// The caller must ensure that `new_size` is greater than or equal to zero. If it's equal
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// to zero, it's catched beforehand.
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unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
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let new_ptr = self.alloc(new_layout)?;
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let new_ptr = self.alloc(new_layout)?;
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// SAFETY: because `new_size` must be greater than or equal to `size`, both the old and new
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// SAFETY: because `new_size` must be greater than or equal to `size`, both the old and new
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@ -206,10 +208,11 @@ pub unsafe trait AllocRef {
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// `copy_nonoverlapping` is safe.
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// `copy_nonoverlapping` is safe.
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// The safety contract for `dealloc` must be upheld by the caller.
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// The safety contract for `dealloc` must be upheld by the caller.
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unsafe {
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unsafe {
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ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_non_null_ptr().as_ptr(), size);
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ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), size);
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self.dealloc(ptr, layout);
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self.dealloc(ptr, layout);
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Ok(new_ptr)
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}
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}
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Ok(new_ptr)
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}
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}
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/// Behaves like `grow`, but also ensures that the new contents are set to zero before being
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/// Behaves like `grow`, but also ensures that the new contents are set to zero before being
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@ -218,12 +221,12 @@ pub unsafe trait AllocRef {
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/// The memory block will contain the following contents after a successful call to
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/// The memory block will contain the following contents after a successful call to
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/// `grow_zeroed`:
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/// `grow_zeroed`:
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/// * Bytes `0..layout.size()` are preserved from the original allocation.
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/// * Bytes `0..layout.size()` are preserved from the original allocation.
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/// * Bytes `layout.size()..old_size` will either be preserved or zeroed,
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/// * Bytes `layout.size()..old_size` will either be preserved or zeroed, depending on the
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/// depending on the allocator implementation. `old_size` refers to the size of
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/// allocator implementation. `old_size` refers to the size of the memory block prior to
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/// the `MemoryBlock` prior to the `grow_zeroed` call, which may be larger than the size
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/// the `grow_zeroed` call, which may be larger than the size that was originally requested
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/// that was originally requested when it was allocated.
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/// when it was allocated.
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/// * Bytes `old_size..new_size` are zeroed. `new_size` refers to
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/// * Bytes `old_size..new_size` are zeroed. `new_size` refers to the size of the memory
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/// the size of the `MemoryBlock` returned by the `grow` call.
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/// block returned by the `grow` call.
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///
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///
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/// # Safety
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/// # Safety
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///
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///
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@ -261,12 +264,9 @@ pub unsafe trait AllocRef {
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"`new_size` must be greater than or equal to `layout.size()`"
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"`new_size` must be greater than or equal to `layout.size()`"
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);
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);
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|
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let new_layout =
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// SAFETY: the caller must ensure that the `new_size` does not overflow.
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// SAFETY: the caller must ensure that the `new_size` does not overflow.
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// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
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// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
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let new_layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
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// The caller must ensure that `new_size` is greater than or equal to zero. If it's equal
|
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// to zero, it's caught beforehand.
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unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
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let new_ptr = self.alloc_zeroed(new_layout)?;
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let new_ptr = self.alloc_zeroed(new_layout)?;
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|
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// SAFETY: because `new_size` must be greater than or equal to `size`, both the old and new
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// SAFETY: because `new_size` must be greater than or equal to `size`, both the old and new
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@ -275,10 +275,11 @@ pub unsafe trait AllocRef {
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// `copy_nonoverlapping` is safe.
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// `copy_nonoverlapping` is safe.
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// The safety contract for `dealloc` must be upheld by the caller.
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// The safety contract for `dealloc` must be upheld by the caller.
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unsafe {
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unsafe {
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ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_non_null_ptr().as_ptr(), size);
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ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), size);
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self.dealloc(ptr, layout);
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self.dealloc(ptr, layout);
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Ok(new_ptr)
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}
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}
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Ok(new_ptr)
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}
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}
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|
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/// Attempts to shrink the memory block.
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/// Attempts to shrink the memory block.
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@ -290,8 +291,8 @@ pub unsafe trait AllocRef {
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///
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///
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/// If this returns `Ok`, then ownership of the memory block referenced by `ptr` has been
|
/// If this returns `Ok`, then ownership of the memory block referenced by `ptr` has been
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||||||
/// transferred to this allocator. The memory may or may not have been freed, and should be
|
/// transferred to this allocator. The memory may or may not have been freed, and should be
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/// considered unusable unless it was transferred back to the caller again via the
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/// considered unusable unless it was transferred back to the caller again via the return value
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/// return value of this method.
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/// of this method.
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///
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///
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/// If this method returns `Err`, then ownership of the memory block has not been transferred to
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/// If this method returns `Err`, then ownership of the memory block has not been transferred to
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||||||
/// this allocator, and the contents of the memory block are unaltered.
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/// this allocator, and the contents of the memory block are unaltered.
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|
@ -332,11 +333,9 @@ pub unsafe trait AllocRef {
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"`new_size` must be smaller than or equal to `layout.size()`"
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"`new_size` must be smaller than or equal to `layout.size()`"
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);
|
);
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|
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let new_layout =
|
|
||||||
// SAFETY: the caller must ensure that the `new_size` does not overflow.
|
// SAFETY: the caller must ensure that the `new_size` does not overflow.
|
||||||
// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
|
// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
|
||||||
// The caller must ensure that `new_size` is greater than zero.
|
let new_layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
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unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
|
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let new_ptr = self.alloc(new_layout)?;
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let new_ptr = self.alloc(new_layout)?;
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|
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||||||
// SAFETY: because `new_size` must be lower than or equal to `size`, both the old and new
|
// SAFETY: because `new_size` must be lower than or equal to `size`, both the old and new
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||||||
|
@ -345,10 +344,11 @@ pub unsafe trait AllocRef {
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||||||
// `copy_nonoverlapping` is safe.
|
// `copy_nonoverlapping` is safe.
|
||||||
// The safety contract for `dealloc` must be upheld by the caller.
|
// The safety contract for `dealloc` must be upheld by the caller.
|
||||||
unsafe {
|
unsafe {
|
||||||
ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_non_null_ptr().as_ptr(), size);
|
ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), size);
|
||||||
self.dealloc(ptr, layout);
|
self.dealloc(ptr, layout);
|
||||||
Ok(new_ptr)
|
|
||||||
}
|
}
|
||||||
|
|
||||||
|
Ok(new_ptr)
|
||||||
}
|
}
|
||||||
|
|
||||||
/// Creates a "by reference" adaptor for this instance of `AllocRef`.
|
/// Creates a "by reference" adaptor for this instance of `AllocRef`.
|
||||||
|
|
|
@ -131,32 +131,75 @@ pub use alloc_crate::alloc::*;
|
||||||
#[derive(Debug, Default, Copy, Clone)]
|
#[derive(Debug, Default, Copy, Clone)]
|
||||||
pub struct System;
|
pub struct System;
|
||||||
|
|
||||||
|
impl System {
|
||||||
|
#[inline]
|
||||||
|
fn alloc_impl(&mut self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
|
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 {
|
||||||
|
GlobalAlloc::alloc_zeroed(self, layout)
|
||||||
|
} else {
|
||||||
|
GlobalAlloc::alloc(self, layout)
|
||||||
|
};
|
||||||
|
let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
|
||||||
|
Ok(NonNull::slice_from_raw_parts(ptr, size))
|
||||||
|
},
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// Safety: Same as `AllocRef::grow`
|
||||||
|
#[inline]
|
||||||
|
unsafe fn grow_impl(
|
||||||
|
&mut self,
|
||||||
|
ptr: NonNull<u8>,
|
||||||
|
layout: Layout,
|
||||||
|
new_size: usize,
|
||||||
|
zeroed: bool,
|
||||||
|
) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
|
debug_assert!(
|
||||||
|
new_size >= layout.size(),
|
||||||
|
"`new_size` must be greater than or equal to `layout.size()`"
|
||||||
|
);
|
||||||
|
|
||||||
|
match layout.size() {
|
||||||
|
// SAFETY: the caller must ensure that the `new_size` does not overflow.
|
||||||
|
// `layout.align()` comes from a `Layout` and is thus guaranteed to be valid for a Layout.
|
||||||
|
0 => unsafe {
|
||||||
|
let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
|
||||||
|
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 => unsafe {
|
||||||
|
// `realloc` probably checks for `new_size >= size` or something similar.
|
||||||
|
intrinsics::assume(new_size >= layout.size());
|
||||||
|
|
||||||
|
let raw_ptr = GlobalAlloc::realloc(self, ptr.as_ptr(), layout, new_size);
|
||||||
|
let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
|
||||||
|
if zeroed {
|
||||||
|
raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
|
||||||
|
}
|
||||||
|
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
|
||||||
|
},
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
// The AllocRef impl checks the layout size to be non-zero and forwards to the GlobalAlloc impl,
|
// The AllocRef impl checks the layout size to be non-zero and forwards to the GlobalAlloc impl,
|
||||||
// which is in `std::sys::*::alloc`.
|
// which is in `std::sys::*::alloc`.
|
||||||
#[unstable(feature = "allocator_api", issue = "32838")]
|
#[unstable(feature = "allocator_api", issue = "32838")]
|
||||||
unsafe impl AllocRef for System {
|
unsafe impl AllocRef for System {
|
||||||
#[inline]
|
#[inline]
|
||||||
fn alloc(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
|
fn alloc(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
let size = layout.size();
|
self.alloc_impl(layout, false)
|
||||||
let ptr = if size == 0 {
|
|
||||||
layout.dangling()
|
|
||||||
} else {
|
|
||||||
// SAFETY: `layout` is non-zero in size,
|
|
||||||
unsafe { NonNull::new(GlobalAlloc::alloc(&System, layout)).ok_or(AllocErr)? }
|
|
||||||
};
|
|
||||||
Ok(NonNull::slice_from_raw_parts(ptr, size))
|
|
||||||
}
|
}
|
||||||
|
|
||||||
#[inline]
|
#[inline]
|
||||||
fn alloc_zeroed(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
|
fn alloc_zeroed(&mut self, layout: Layout) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
let size = layout.size();
|
self.alloc_impl(layout, true)
|
||||||
let ptr = if size == 0 {
|
|
||||||
layout.dangling()
|
|
||||||
} else {
|
|
||||||
// SAFETY: `layout` is non-zero in size,
|
|
||||||
unsafe { NonNull::new(GlobalAlloc::alloc_zeroed(&System, layout)).ok_or(AllocErr)? }
|
|
||||||
};
|
|
||||||
Ok(NonNull::slice_from_raw_parts(ptr, size))
|
|
||||||
}
|
}
|
||||||
|
|
||||||
#[inline]
|
#[inline]
|
||||||
|
@ -164,7 +207,7 @@ unsafe impl AllocRef for System {
|
||||||
if layout.size() != 0 {
|
if layout.size() != 0 {
|
||||||
// SAFETY: `layout` is non-zero in size,
|
// SAFETY: `layout` is non-zero in size,
|
||||||
// other conditions must be upheld by the caller
|
// other conditions must be upheld by the caller
|
||||||
unsafe { GlobalAlloc::dealloc(&System, ptr.as_ptr(), layout) }
|
unsafe { GlobalAlloc::dealloc(self, ptr.as_ptr(), layout) }
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -175,26 +218,8 @@ unsafe impl AllocRef for System {
|
||||||
layout: Layout,
|
layout: Layout,
|
||||||
new_size: usize,
|
new_size: usize,
|
||||||
) -> Result<NonNull<[u8]>, AllocErr> {
|
) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
debug_assert!(
|
// SAFETY: all conditions must be upheld by the caller
|
||||||
new_size >= layout.size(),
|
unsafe { self.grow_impl(ptr, layout, new_size, false) }
|
||||||
"`new_size` must be greater than or equal to `layout.size()`"
|
|
||||||
);
|
|
||||||
|
|
||||||
// SAFETY: `new_size` must be non-zero, which is checked in the match expression.
|
|
||||||
// If `new_size` is zero, then `old_size` has to be zero as well.
|
|
||||||
// Other conditions must be upheld by the caller
|
|
||||||
unsafe {
|
|
||||||
match layout.size() {
|
|
||||||
0 => self.alloc(Layout::from_size_align_unchecked(new_size, layout.align())),
|
|
||||||
old_size => {
|
|
||||||
// `realloc` probably checks for `new_size >= size` or something similar.
|
|
||||||
intrinsics::assume(new_size >= old_size);
|
|
||||||
let raw_ptr = GlobalAlloc::realloc(&System, ptr.as_ptr(), layout, new_size);
|
|
||||||
let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
|
|
||||||
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
}
|
||||||
|
|
||||||
#[inline]
|
#[inline]
|
||||||
|
@ -204,27 +229,8 @@ unsafe impl AllocRef for System {
|
||||||
layout: Layout,
|
layout: Layout,
|
||||||
new_size: usize,
|
new_size: usize,
|
||||||
) -> Result<NonNull<[u8]>, AllocErr> {
|
) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
debug_assert!(
|
// SAFETY: all conditions must be upheld by the caller
|
||||||
new_size >= layout.size(),
|
unsafe { self.grow_impl(ptr, layout, new_size, true) }
|
||||||
"`new_size` must be greater than or equal to `layout.size()`"
|
|
||||||
);
|
|
||||||
|
|
||||||
// SAFETY: `new_size` must be non-zero, which is checked in the match expression.
|
|
||||||
// If `new_size` is zero, then `old_size` has to be zero as well.
|
|
||||||
// Other conditions must be upheld by the caller
|
|
||||||
unsafe {
|
|
||||||
match layout.size() {
|
|
||||||
0 => self.alloc_zeroed(Layout::from_size_align_unchecked(new_size, layout.align())),
|
|
||||||
old_size => {
|
|
||||||
// `realloc` probably checks for `new_size >= size` or something similar.
|
|
||||||
intrinsics::assume(new_size >= old_size);
|
|
||||||
let raw_ptr = GlobalAlloc::realloc(&System, ptr.as_ptr(), layout, new_size);
|
|
||||||
raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
|
|
||||||
let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
|
|
||||||
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
}
|
||||||
|
|
||||||
#[inline]
|
#[inline]
|
||||||
|
@ -234,32 +240,31 @@ unsafe impl AllocRef for System {
|
||||||
layout: Layout,
|
layout: Layout,
|
||||||
new_size: usize,
|
new_size: usize,
|
||||||
) -> Result<NonNull<[u8]>, AllocErr> {
|
) -> Result<NonNull<[u8]>, AllocErr> {
|
||||||
let old_size = layout.size();
|
|
||||||
debug_assert!(
|
debug_assert!(
|
||||||
new_size <= old_size,
|
new_size <= layout.size(),
|
||||||
"`new_size` must be smaller than or equal to `layout.size()`"
|
"`new_size` must be smaller than or equal to `layout.size()`"
|
||||||
);
|
);
|
||||||
|
|
||||||
let ptr = if new_size == 0 {
|
match new_size {
|
||||||
// SAFETY: conditions must be upheld by the caller
|
// SAFETY: conditions must be upheld by the caller
|
||||||
unsafe {
|
0 => unsafe {
|
||||||
self.dealloc(ptr, layout);
|
self.dealloc(ptr, layout);
|
||||||
}
|
Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0))
|
||||||
layout.dangling()
|
},
|
||||||
} else {
|
|
||||||
// SAFETY: new_size is not zero,
|
|
||||||
// Other conditions must be upheld by the caller
|
|
||||||
let raw_ptr = unsafe {
|
|
||||||
// `realloc` probably checks for `new_size <= old_size` or something similar.
|
|
||||||
intrinsics::assume(new_size <= old_size);
|
|
||||||
GlobalAlloc::realloc(&System, ptr.as_ptr(), layout, new_size)
|
|
||||||
};
|
|
||||||
NonNull::new(raw_ptr).ok_or(AllocErr)?
|
|
||||||
};
|
|
||||||
|
|
||||||
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
|
// SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
|
||||||
|
new_size => unsafe {
|
||||||
|
// `realloc` probably checks for `new_size <= size` or something similar.
|
||||||
|
intrinsics::assume(new_size <= layout.size());
|
||||||
|
|
||||||
|
let raw_ptr = GlobalAlloc::realloc(self, ptr.as_ptr(), layout, new_size);
|
||||||
|
let ptr = NonNull::new(raw_ptr).ok_or(AllocErr)?;
|
||||||
|
Ok(NonNull::slice_from_raw_parts(ptr, new_size))
|
||||||
|
},
|
||||||
|
}
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
|
static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
|
||||||
|
|
||||||
/// Registers a custom allocation error hook, replacing any that was previously registered.
|
/// Registers a custom allocation error hook, replacing any that was previously registered.
|
||||||
|
|
Loading…
Reference in a new issue