some cleanup for bevy_ptr (#4668)

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 https://github.com/rust-lang/rust/pull/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)`
This commit is contained in:
Jakob Hellermann 2022-05-06 19:15:24 +00:00
parent ec805e9e07
commit d63b7e9568
2 changed files with 8 additions and 20 deletions

View file

@ -212,7 +212,7 @@ impl BlobVec {
#[inline] #[inline]
pub unsafe fn get_unchecked(&self, index: usize) -> Ptr<'_> { pub unsafe fn get_unchecked(&self, index: usize) -> Ptr<'_> {
debug_assert!(index < self.len()); 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 /// # Safety
@ -221,7 +221,7 @@ impl BlobVec {
pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> PtrMut<'_> { pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> PtrMut<'_> {
debug_assert!(index < self.len()); debug_assert!(index < self.len());
let layout_size = self.item_layout.size(); 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 /// Gets a [`Ptr`] to the start of the vec
@ -258,7 +258,7 @@ impl BlobVec {
unsafe { unsafe {
// NOTE: this doesn't use self.get_unchecked(i) because the debug_assert on index // 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 // 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); (drop)(ptr);
} }
} }

View file

@ -55,7 +55,7 @@ macro_rules! impl_ptr {
/// ///
/// [ptr_offset]: https://doc.rust-lang.org/std/primitive.pointer.html#method.offset /// [ptr_offset]: https://doc.rust-lang.org/std/primitive.pointer.html#method.offset
#[inline] #[inline]
pub unsafe fn offset(self, count: isize) -> Self { pub unsafe fn byte_offset(self, count: isize) -> Self {
Self( Self(
NonNull::new_unchecked(self.as_ptr().offset(count)), NonNull::new_unchecked(self.as_ptr().offset(count)),
PhantomData, PhantomData,
@ -73,7 +73,7 @@ macro_rules! impl_ptr {
/// ///
/// [ptr_add]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add /// [ptr_add]: https://doc.rust-lang.org/std/primitive.pointer.html#method.add
#[inline] #[inline]
pub unsafe fn add(self, count: usize) -> Self { pub unsafe fn byte_add(self, count: usize) -> Self {
Self( Self(
NonNull::new_unchecked(self.as_ptr().add(count)), NonNull::new_unchecked(self.as_ptr().add(count)),
PhantomData, PhantomData,
@ -116,13 +116,9 @@ impl<'a> Ptr<'a> {
/// ///
/// If possible, it is strongly encouraged to use [`deref`](Self::deref) over this function, /// If possible, it is strongly encouraged to use [`deref`](Self::deref) over this function,
/// as it retains the lifetime. /// as it retains the lifetime.
///
/// # Safety
/// All subsequent operations to the returned pointer must be valid inside the
/// associated lifetime.
#[inline] #[inline]
#[allow(clippy::wrong_self_convention)] #[allow(clippy::wrong_self_convention)]
pub unsafe fn as_ptr(self) -> *mut u8 { pub fn as_ptr(self) -> *mut u8 {
self.0.as_ptr() self.0.as_ptr()
} }
} }
@ -150,13 +146,9 @@ impl<'a> PtrMut<'a> {
/// ///
/// If possible, it is strongly encouraged to use [`deref_mut`](Self::deref_mut) over /// If possible, it is strongly encouraged to use [`deref_mut`](Self::deref_mut) over
/// this function, as it retains the lifetime. /// this function, as it retains the lifetime.
///
/// # Safety
/// All subsequent operations to the returned pointer must be valid inside the
/// associated lifetime.
#[inline] #[inline]
#[allow(clippy::wrong_self_convention)] #[allow(clippy::wrong_self_convention)]
pub unsafe fn as_ptr(self) -> *mut u8 { pub fn as_ptr(&self) -> *mut u8 {
self.0.as_ptr() self.0.as_ptr()
} }
} }
@ -192,13 +184,9 @@ impl<'a> OwningPtr<'a> {
/// ///
/// If possible, it is strongly encouraged to use the other more type-safe functions /// If possible, it is strongly encouraged to use the other more type-safe functions
/// over this function. /// over this function.
///
/// # Safety
/// All subsequent operations to the returned pointer must be valid inside the
/// associated lifetime.
#[inline] #[inline]
#[allow(clippy::wrong_self_convention)] #[allow(clippy::wrong_self_convention)]
pub unsafe fn as_ptr(self) -> *mut u8 { pub fn as_ptr(&self) -> *mut u8 {
self.0.as_ptr() self.0.as_ptr()
} }
} }