split core::ptr module into multiple files #61159
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,226 @@ | ||
| use crate::convert::From; | ||
| use crate::ops::{CoerceUnsized, DispatchFromDyn}; | ||
| use crate::fmt; | ||
| use crate::hash; | ||
| use crate::marker::Unsize; | ||
| use crate::mem; | ||
| use crate::ptr::Unique; | ||
| use crate::cmp::Ordering; | ||
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| /// `*mut T` but non-zero and covariant. | ||
| /// | ||
| /// This is often the correct thing to use when building data structures using | ||
| /// raw pointers, but is ultimately more dangerous to use because of its additional | ||
| /// properties. If you're not sure if you should use `NonNull<T>`, just use `*mut T`! | ||
| /// | ||
| /// Unlike `*mut T`, the pointer must always be non-null, even if the pointer | ||
| /// is never dereferenced. This is so that enums may use this forbidden value | ||
| /// as a discriminant -- `Option<NonNull<T>>` has the same size as `*mut T`. | ||
| /// However the pointer may still dangle if it isn't dereferenced. | ||
| /// | ||
| /// Unlike `*mut T`, `NonNull<T>` is covariant over `T`. If this is incorrect | ||
| /// for your use case, you should include some [`PhantomData`] in your type to | ||
| /// provide invariance, such as `PhantomData<Cell<T>>` or `PhantomData<&'a mut T>`. | ||
| /// Usually this won't be necessary; covariance is correct for most safe abstractions, | ||
| /// such as `Box`, `Rc`, `Arc`, `Vec`, and `LinkedList`. This is the case because they | ||
| /// provide a public API that follows the normal shared XOR mutable rules of Rust. | ||
| /// | ||
| /// Notice that `NonNull<T>` has a `From` instance for `&T`. However, this does | ||
| /// not change the fact that mutating through a (pointer derived from a) shared | ||
| /// reference is undefined behavior unless the mutation happens inside an | ||
| /// [`UnsafeCell<T>`]. The same goes for creating a mutable reference from a shared | ||
| /// reference. When using this `From` instance without an `UnsafeCell<T>`, | ||
| /// it is your responsibility to ensure that `as_mut` is never called, and `as_ptr` | ||
| /// is never used for mutation. | ||
| /// | ||
| /// [`PhantomData`]: ../marker/struct.PhantomData.html | ||
| /// [`UnsafeCell<T>`]: ../cell/struct.UnsafeCell.html | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[repr(transparent)] | ||
| #[rustc_layout_scalar_valid_range_start(1)] | ||
| #[cfg_attr(not(stage0), rustc_nonnull_optimization_guaranteed)] | ||
| pub struct NonNull<T: ?Sized> { | ||
| pointer: *const T, | ||
| } | ||
|
|
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| /// `NonNull` pointers are not `Send` because the data they reference may be aliased. | ||
| // N.B., this impl is unnecessary, but should provide better error messages. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> !Send for NonNull<T> { } | ||
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| /// `NonNull` pointers are not `Sync` because the data they reference may be aliased. | ||
| // N.B., this impl is unnecessary, but should provide better error messages. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> !Sync for NonNull<T> { } | ||
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| impl<T: Sized> NonNull<T> { | ||
| /// Creates a new `NonNull` that is dangling, but well-aligned. | ||
| /// | ||
| /// This is useful for initializing types which lazily allocate, like | ||
| /// `Vec::new` does. | ||
| /// | ||
| /// Note that the pointer value may potentially represent a valid pointer to | ||
| /// a `T`, which means this must not be used as a "not yet initialized" | ||
| /// sentinel value. Types that lazily allocate must track initialization by | ||
| /// some other means. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[inline] | ||
| pub const fn dangling() -> Self { | ||
| unsafe { | ||
| let ptr = mem::align_of::<T>() as *mut T; | ||
| NonNull::new_unchecked(ptr) | ||
| } | ||
| } | ||
| } | ||
|
|
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| impl<T: ?Sized> NonNull<T> { | ||
| /// Creates a new `NonNull`. | ||
| /// | ||
| /// # Safety | ||
| /// | ||
| /// `ptr` must be non-null. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[inline] | ||
| pub const unsafe fn new_unchecked(ptr: *mut T) -> Self { | ||
| NonNull { pointer: ptr as _ } | ||
| } | ||
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| /// Creates a new `NonNull` if `ptr` is non-null. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[inline] | ||
| pub fn new(ptr: *mut T) -> Option<Self> { | ||
| if !ptr.is_null() { | ||
| Some(unsafe { Self::new_unchecked(ptr) }) | ||
| } else { | ||
| None | ||
| } | ||
| } | ||
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| /// Acquires the underlying `*mut` pointer. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[inline] | ||
| pub const fn as_ptr(self) -> *mut T { | ||
| self.pointer as *mut T | ||
| } | ||
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| /// Dereferences the content. | ||
| /// | ||
| /// The resulting lifetime is bound to self so this behaves "as if" | ||
| /// it were actually an instance of T that is getting borrowed. If a longer | ||
| /// (unbound) lifetime is needed, use `&*my_ptr.as_ptr()`. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[inline] | ||
| pub unsafe fn as_ref(&self) -> &T { | ||
| &*self.as_ptr() | ||
| } | ||
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| /// Mutably dereferences the content. | ||
| /// | ||
| /// The resulting lifetime is bound to self so this behaves "as if" | ||
| /// it were actually an instance of T that is getting borrowed. If a longer | ||
| /// (unbound) lifetime is needed, use `&mut *my_ptr.as_ptr()`. | ||
| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| #[inline] | ||
| pub unsafe fn as_mut(&mut self) -> &mut T { | ||
| &mut *self.as_ptr() | ||
| } | ||
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| /// Cast to a pointer of another type | ||
| #[stable(feature = "nonnull_cast", since = "1.27.0")] | ||
| #[inline] | ||
| pub const fn cast<U>(self) -> NonNull<U> { | ||
| unsafe { | ||
| NonNull::new_unchecked(self.as_ptr() as *mut U) | ||
| } | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> Clone for NonNull<T> { | ||
| #[inline] | ||
| fn clone(&self) -> Self { | ||
| *self | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> Copy for NonNull<T> { } | ||
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| #[unstable(feature = "coerce_unsized", issue = "27732")] | ||
| impl<T: ?Sized, U: ?Sized> CoerceUnsized<NonNull<U>> for NonNull<T> where T: Unsize<U> { } | ||
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| #[unstable(feature = "dispatch_from_dyn", issue = "0")] | ||
| impl<T: ?Sized, U: ?Sized> DispatchFromDyn<NonNull<U>> for NonNull<T> where T: Unsize<U> { } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> fmt::Debug for NonNull<T> { | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| fmt::Pointer::fmt(&self.as_ptr(), f) | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> fmt::Pointer for NonNull<T> { | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| fmt::Pointer::fmt(&self.as_ptr(), f) | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> Eq for NonNull<T> {} | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> PartialEq for NonNull<T> { | ||
| #[inline] | ||
| fn eq(&self, other: &Self) -> bool { | ||
| self.as_ptr() == other.as_ptr() | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> Ord for NonNull<T> { | ||
| #[inline] | ||
| fn cmp(&self, other: &Self) -> Ordering { | ||
| self.as_ptr().cmp(&other.as_ptr()) | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> PartialOrd for NonNull<T> { | ||
| #[inline] | ||
| fn partial_cmp(&self, other: &Self) -> Option<Ordering> { | ||
| self.as_ptr().partial_cmp(&other.as_ptr()) | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> hash::Hash for NonNull<T> { | ||
| #[inline] | ||
| fn hash<H: hash::Hasher>(&self, state: &mut H) { | ||
| self.as_ptr().hash(state) | ||
| } | ||
| } | ||
|
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> From<Unique<T>> for NonNull<T> { | ||
| #[inline] | ||
| fn from(unique: Unique<T>) -> Self { | ||
| unsafe { NonNull::new_unchecked(unique.as_ptr()) } | ||
| } | ||
| } | ||
|
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> From<&mut T> for NonNull<T> { | ||
| #[inline] | ||
| fn from(reference: &mut T) -> Self { | ||
| unsafe { NonNull { pointer: reference as *mut T } } | ||
| } | ||
| } | ||
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| #[stable(feature = "nonnull", since = "1.25.0")] | ||
| impl<T: ?Sized> From<&T> for NonNull<T> { | ||
| #[inline] | ||
| fn from(reference: &T) -> Self { | ||
| unsafe { NonNull { pointer: reference as *const T } } | ||
| } | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,180 @@ | ||
| use crate::convert::From; | ||
| use crate::ops::{CoerceUnsized, DispatchFromDyn}; | ||
| use crate::fmt; | ||
| use crate::marker::{PhantomData, Unsize}; | ||
| use crate::mem; | ||
| use crate::ptr::NonNull; | ||
|
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| /// A wrapper around a raw non-null `*mut T` that indicates that the possessor | ||
| /// of this wrapper owns the referent. Useful for building abstractions like | ||
| /// `Box<T>`, `Vec<T>`, `String`, and `HashMap<K, V>`. | ||
| /// | ||
| /// Unlike `*mut T`, `Unique<T>` behaves "as if" it were an instance of `T`. | ||
| /// It implements `Send`/`Sync` if `T` is `Send`/`Sync`. It also implies | ||
| /// the kind of strong aliasing guarantees an instance of `T` can expect: | ||
| /// the referent of the pointer should not be modified without a unique path to | ||
| /// its owning Unique. | ||
| /// | ||
| /// If you're uncertain of whether it's correct to use `Unique` for your purposes, | ||
| /// consider using `NonNull`, which has weaker semantics. | ||
| /// | ||
| /// Unlike `*mut T`, the pointer must always be non-null, even if the pointer | ||
| /// is never dereferenced. This is so that enums may use this forbidden value | ||
| /// as a discriminant -- `Option<Unique<T>>` has the same size as `Unique<T>`. | ||
| /// However the pointer may still dangle if it isn't dereferenced. | ||
| /// | ||
| /// Unlike `*mut T`, `Unique<T>` is covariant over `T`. This should always be correct | ||
| /// for any type which upholds Unique's aliasing requirements. | ||
| #[unstable(feature = "ptr_internals", issue = "0", | ||
| reason = "use NonNull instead and consider PhantomData<T> \ | ||
| (if you also use #[may_dangle]), Send, and/or Sync")] | ||
| #[doc(hidden)] | ||
| #[repr(transparent)] | ||
| #[rustc_layout_scalar_valid_range_start(1)] | ||
| pub struct Unique<T: ?Sized> { | ||
| pointer: *const T, | ||
| // NOTE: this marker has no consequences for variance, but is necessary | ||
| // for dropck to understand that we logically own a `T`. | ||
| // | ||
| // For details, see: | ||
| // https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md#phantom-data | ||
| _marker: PhantomData<T>, | ||
| } | ||
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| /// `Unique` pointers are `Send` if `T` is `Send` because the data they | ||
| /// reference is unaliased. Note that this aliasing invariant is | ||
| /// unenforced by the type system; the abstraction using the | ||
| /// `Unique` must enforce it. | ||
| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| unsafe impl<T: Send + ?Sized> Send for Unique<T> { } | ||
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| /// `Unique` pointers are `Sync` if `T` is `Sync` because the data they | ||
| /// reference is unaliased. Note that this aliasing invariant is | ||
| /// unenforced by the type system; the abstraction using the | ||
| /// `Unique` must enforce it. | ||
| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| unsafe impl<T: Sync + ?Sized> Sync for Unique<T> { } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: Sized> Unique<T> { | ||
| /// Creates a new `Unique` that is dangling, but well-aligned. | ||
| /// | ||
| /// This is useful for initializing types which lazily allocate, like | ||
| /// `Vec::new` does. | ||
| /// | ||
| /// Note that the pointer value may potentially represent a valid pointer to | ||
| /// a `T`, which means this must not be used as a "not yet initialized" | ||
| /// sentinel value. Types that lazily allocate must track initialization by | ||
| /// some other means. | ||
| // FIXME: rename to dangling() to match NonNull? | ||
| #[inline] | ||
| pub const fn empty() -> Self { | ||
| unsafe { | ||
| Unique::new_unchecked(mem::align_of::<T>() as *mut T) | ||
| } | ||
| } | ||
| } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> Unique<T> { | ||
| /// Creates a new `Unique`. | ||
| /// | ||
| /// # Safety | ||
| /// | ||
| /// `ptr` must be non-null. | ||
| #[inline] | ||
| pub const unsafe fn new_unchecked(ptr: *mut T) -> Self { | ||
| Unique { pointer: ptr as _, _marker: PhantomData } | ||
| } | ||
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| /// Creates a new `Unique` if `ptr` is non-null. | ||
| #[inline] | ||
| pub fn new(ptr: *mut T) -> Option<Self> { | ||
| if !ptr.is_null() { | ||
| Some(unsafe { Unique { pointer: ptr as _, _marker: PhantomData } }) | ||
| } else { | ||
| None | ||
| } | ||
| } | ||
|
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| /// Acquires the underlying `*mut` pointer. | ||
| #[inline] | ||
|
There was a problem hiding this comment. I made this and the other methods here |
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| pub const fn as_ptr(self) -> *mut T { | ||
| self.pointer as *mut T | ||
| } | ||
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| /// Dereferences the content. | ||
| /// | ||
| /// The resulting lifetime is bound to self so this behaves "as if" | ||
| /// it were actually an instance of T that is getting borrowed. If a longer | ||
| /// (unbound) lifetime is needed, use `&*my_ptr.as_ptr()`. | ||
| #[inline] | ||
| pub unsafe fn as_ref(&self) -> &T { | ||
| &*self.as_ptr() | ||
| } | ||
|
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| /// Mutably dereferences the content. | ||
| /// | ||
| /// The resulting lifetime is bound to self so this behaves "as if" | ||
| /// it were actually an instance of T that is getting borrowed. If a longer | ||
| /// (unbound) lifetime is needed, use `&mut *my_ptr.as_ptr()`. | ||
| #[inline] | ||
| pub unsafe fn as_mut(&mut self) -> &mut T { | ||
| &mut *self.as_ptr() | ||
| } | ||
| } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> Clone for Unique<T> { | ||
| #[inline] | ||
| fn clone(&self) -> Self { | ||
| *self | ||
| } | ||
| } | ||
|
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> Copy for Unique<T> { } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized, U: ?Sized> CoerceUnsized<Unique<U>> for Unique<T> where T: Unsize<U> { } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized, U: ?Sized> DispatchFromDyn<Unique<U>> for Unique<T> where T: Unsize<U> { } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> fmt::Debug for Unique<T> { | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| fmt::Pointer::fmt(&self.as_ptr(), f) | ||
| } | ||
| } | ||
|
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> fmt::Pointer for Unique<T> { | ||
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| fmt::Pointer::fmt(&self.as_ptr(), f) | ||
| } | ||
| } | ||
|
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> From<&mut T> for Unique<T> { | ||
| #[inline] | ||
| fn from(reference: &mut T) -> Self { | ||
| unsafe { Unique { pointer: reference as *mut T, _marker: PhantomData } } | ||
| } | ||
| } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<T: ?Sized> From<&T> for Unique<T> { | ||
| #[inline] | ||
| fn from(reference: &T) -> Self { | ||
| unsafe { Unique { pointer: reference as *const T, _marker: PhantomData } } | ||
| } | ||
| } | ||
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| #[unstable(feature = "ptr_internals", issue = "0")] | ||
| impl<'a, T: ?Sized> From<NonNull<T>> for Unique<T> { | ||
| #[inline] | ||
| fn from(p: NonNull<T>) -> Self { | ||
| unsafe { Unique::new_unchecked(p.as_ptr()) } | ||
|
There was a problem hiding this comment. I had to adjust this to use the public API of |
||
| } | ||
| } | ||
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I had to rewrite this using the public API of
Unique.