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some cleanup for bevy_ptr (#4668)
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1. change `PtrMut::as_ptr(self)` and `OwnedPtr::as_ptr(self)` to take `&self`, otherwise printing the pointer will prevent doing anything else afterwards
2. make all `as_ptr` methods safe. There's nothing unsafe about obtaining a pointer, these kinds of methods are safe in std as well [str::as_ptr](https://doc.rust-lang.org/stable/std/primitive.str.html#method.as_ptr), [Rc::as_ptr](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.as_ptr)
3. rename `offset`/`add` to `byte_offset`/`byte_add`. The unprefixed methods in std add in increments of `std::mem::size_of::<T>`, not in bytes. There's a PR for rust to add these byte_ methods rust-lang/rust#95643 and at the call site it makes it much more clear that you need to do `.byte_add(i * layout_size)` instead of `.add(i)`
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jakobhellermann committed May 6, 2022
1 parent ec805e9 commit d63b7e9
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Showing 2 changed files with 8 additions and 20 deletions.
6 changes: 3 additions & 3 deletions crates/bevy_ecs/src/storage/blob_vec.rs
Original file line number Diff line number Diff line change
Expand Up @@ -212,7 +212,7 @@ impl BlobVec {
#[inline]
pub unsafe fn get_unchecked(&self, index: usize) -> Ptr<'_> {
debug_assert!(index < self.len());
self.get_ptr().add(index * self.item_layout.size())
self.get_ptr().byte_add(index * self.item_layout.size())
}

/// # Safety
Expand All @@ -221,7 +221,7 @@ impl BlobVec {
pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> PtrMut<'_> {
debug_assert!(index < self.len());
let layout_size = self.item_layout.size();
self.get_ptr_mut().add(index * layout_size)
self.get_ptr_mut().byte_add(index * layout_size)
}

/// Gets a [`Ptr`] to the start of the vec
Expand Down Expand Up @@ -258,7 +258,7 @@ impl BlobVec {
unsafe {
// NOTE: this doesn't use self.get_unchecked(i) because the debug_assert on index
// will panic here due to self.len being set to 0
let ptr = self.get_ptr_mut().add(i * layout_size).promote();
let ptr = self.get_ptr_mut().byte_add(i * layout_size).promote();
(drop)(ptr);
}
}
Expand Down
22 changes: 5 additions & 17 deletions crates/bevy_ptr/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,7 @@ macro_rules! impl_ptr {
///
/// [ptr_offset]: https://doc.rust-lang.org/std/primitive.pointer.html#method.offset
#[inline]
pub unsafe fn offset(self, count: isize) -> Self {
pub unsafe fn byte_offset(self, count: isize) -> Self {
Self(
NonNull::new_unchecked(self.as_ptr().offset(count)),
PhantomData,
Expand All @@ -73,7 +73,7 @@ macro_rules! impl_ptr {
///
/// [ptr_add]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add
#[inline]
pub unsafe fn add(self, count: usize) -> Self {
pub unsafe fn byte_add(self, count: usize) -> Self {
Self(
NonNull::new_unchecked(self.as_ptr().add(count)),
PhantomData,
Expand Down Expand Up @@ -116,13 +116,9 @@ impl<'a> Ptr<'a> {
///
/// If possible, it is strongly encouraged to use [`deref`](Self::deref) over this function,
/// as it retains the lifetime.
///
/// # Safety
/// All subsequent operations to the returned pointer must be valid inside the
/// associated lifetime.
#[inline]
#[allow(clippy::wrong_self_convention)]
pub unsafe fn as_ptr(self) -> *mut u8 {
pub fn as_ptr(self) -> *mut u8 {
self.0.as_ptr()
}
}
Expand Down Expand Up @@ -150,13 +146,9 @@ impl<'a> PtrMut<'a> {
///
/// If possible, it is strongly encouraged to use [`deref_mut`](Self::deref_mut) over
/// this function, as it retains the lifetime.
///
/// # Safety
/// All subsequent operations to the returned pointer must be valid inside the
/// associated lifetime.
#[inline]
#[allow(clippy::wrong_self_convention)]
pub unsafe fn as_ptr(self) -> *mut u8 {
pub fn as_ptr(&self) -> *mut u8 {
self.0.as_ptr()
}
}
Expand Down Expand Up @@ -192,13 +184,9 @@ impl<'a> OwningPtr<'a> {
///
/// If possible, it is strongly encouraged to use the other more type-safe functions
/// over this function.
///
/// # Safety
/// All subsequent operations to the returned pointer must be valid inside the
/// associated lifetime.
#[inline]
#[allow(clippy::wrong_self_convention)]
pub unsafe fn as_ptr(self) -> *mut u8 {
pub fn as_ptr(&self) -> *mut u8 {
self.0.as_ptr()
}
}
Expand Down

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