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Rollup merge of rust-lang#47631 - SimonSapin:nonnull, r=alexcrichton
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Add some APIs to ptr::NonNull and fix `since` attributes

This is a follow-up to its stabilization in rust-lang#46952. Tracking issue: rust-lang#27730.

* These trait impls are insta-stable: `Hash`, `PartialEq`, `Eq`, `PartialOrd` and `Ord`.
* The new `cast<U>() -> NonNull<U>`  method is `#[unstable]`. It was proposed in rust-lang#46952 (comment).
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@Manishearth
Manishearth committed Feb 7, 2018
2 parents aee2255 + b8ffc8a commit d920f1f
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Showing 2 changed files with 64 additions and 25 deletions.
87 changes: 63 additions & 24 deletions src/libcore/ptr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2461,7 +2461,7 @@ impl<'a, T: ?Sized> From<NonNull<T>> for Unique<T> {
}

/// Previous name of `NonNull`.
#[rustc_deprecated(since = "1.24", reason = "renamed to `NonNull`")]
#[rustc_deprecated(since = "1.25.0", reason = "renamed to `NonNull`")]
#[unstable(feature = "shared", issue = "27730")]
pub type Shared<T> = NonNull<T>;

Expand All @@ -2482,34 +2482,27 @@ pub type Shared<T> = NonNull<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.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub struct NonNull<T: ?Sized> {
pointer: NonZero<*const T>,
}

#[stable(feature = "nonnull", since = "1.24.0")]
impl<T: ?Sized> fmt::Debug for NonNull<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Pointer::fmt(&self.as_ptr(), f)
}
}

/// `NonNull` pointers are not `Send` because the data they reference may be aliased.
// NB: This impl is unnecessary, but should provide better error messages.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> !Send for NonNull<T> { }

/// `NonNull` pointers are not `Sync` because the data they reference may be aliased.
// NB: This impl is unnecessary, but should provide better error messages.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> !Sync for NonNull<T> { }

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.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub fn dangling() -> Self {
unsafe {
let ptr = mem::align_of::<T>() as *mut T;
Expand All @@ -2524,19 +2517,19 @@ impl<T: ?Sized> NonNull<T> {
/// # Safety
///
/// `ptr` must be non-null.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
NonNull { pointer: NonZero::new_unchecked(ptr) }
}

/// Creates a new `NonNull` if `ptr` is non-null.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub fn new(ptr: *mut T) -> Option<Self> {
NonZero::new(ptr as *const T).map(|nz| NonNull { pointer: nz })
}

/// Acquires the underlying `*mut` pointer.
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub fn as_ptr(self) -> *mut T {
self.pointer.get() as *mut T
}
Expand All @@ -2546,7 +2539,7 @@ impl<T: ?Sized> NonNull<T> {
/// 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 = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub unsafe fn as_ref(&self) -> &T {
&*self.as_ptr()
}
Expand All @@ -2556,47 +2549,93 @@ impl<T: ?Sized> NonNull<T> {
/// 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 = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
pub unsafe fn as_mut(&mut self) -> &mut T {
&mut *self.as_ptr()
}

/// Cast to a pointer of another type
#[unstable(feature = "nonnull_cast", issue = "47653")]
pub fn cast<U>(self) -> NonNull<U> {
unsafe {
NonNull::new_unchecked(self.as_ptr() as *mut U)
}
}
}

#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> Clone for NonNull<T> {
fn clone(&self) -> Self {
*self
}
}

#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> Copy for NonNull<T> { }

#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized, U: ?Sized> CoerceUnsized<NonNull<U>> for NonNull<T> where T: Unsize<U> { }

#[stable(feature = "nonnull", since = "1.24.0")]
#[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)
}
}

#[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)
}
}

#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> Eq for NonNull<T> {}

#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> PartialEq for NonNull<T> {
fn eq(&self, other: &Self) -> bool {
self.as_ptr() == other.as_ptr()
}
}

#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> Ord for NonNull<T> {
fn cmp(&self, other: &Self) -> Ordering {
self.as_ptr().cmp(&other.as_ptr())
}
}

#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> PartialOrd for NonNull<T> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.as_ptr().partial_cmp(&other.as_ptr())
}
}

#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> hash::Hash for NonNull<T> {
fn hash<H: hash::Hasher>(&self, state: &mut H) {
self.as_ptr().hash(state)
}
}

#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: ?Sized> From<Unique<T>> for NonNull<T> {
fn from(unique: Unique<T>) -> Self {
NonNull { pointer: unique.pointer }
}
}

#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<'a, T: ?Sized> From<&'a mut T> for NonNull<T> {
fn from(reference: &'a mut T) -> Self {
NonNull { pointer: NonZero::from(reference) }
}
}

#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<'a, T: ?Sized> From<&'a T> for NonNull<T> {
fn from(reference: &'a T) -> Self {
NonNull { pointer: NonZero::from(reference) }
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2 changes: 1 addition & 1 deletion src/libstd/panic.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -198,7 +198,7 @@ impl<T: RefUnwindSafe + ?Sized> UnwindSafe for *const T {}
impl<T: RefUnwindSafe + ?Sized> UnwindSafe for *mut T {}
#[unstable(feature = "ptr_internals", issue = "0")]
impl<T: UnwindSafe + ?Sized> UnwindSafe for Unique<T> {}
#[stable(feature = "nonnull", since = "1.24.0")]
#[stable(feature = "nonnull", since = "1.25.0")]
impl<T: RefUnwindSafe + ?Sized> UnwindSafe for NonNull<T> {}
#[stable(feature = "catch_unwind", since = "1.9.0")]
impl<T: ?Sized> UnwindSafe for Mutex<T> {}
Expand Down

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