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//! Macros for implementing common functionality and traits for the marked
//! pointer types with identical internal structure (Owned, Shared, Unlinked and
//! Unprotected)
macro_rules! impl_trait {
($self:ident) => {
type Pointer = Self;
type Item = T;
type MarkBits = N;
#[inline]
fn as_marked_ptr(&self) -> crate::pointer::MarkedPtr<T, N> {
self.inner.into_marked_ptr()
}
#[inline]
fn into_marked_ptr(self) -> crate::pointer::MarkedPtr<Self::Item, Self::MarkBits> {
self.into_marked_non_null().into_marked_ptr()
}
#[inline]
fn marked($self: Self, tag: usize) -> crate::pointer::Marked<Self::Pointer> {
let inner = $self.inner.with_tag(tag);
crate::pointer::Marked::Value(Self { inner, _marker: PhantomData })
}
#[inline]
fn unmarked($self: Self) -> Self {
let inner = $self.inner.clear_tag();
Self { inner, _marker: PhantomData }
}
#[inline]
fn decompose($self: Self) -> (Self, usize) {
let (inner, tag) = $self.inner.decompose();
core::mem::forget($self);
( Self { inner: crate::pointer::MarkedNonNull::from(inner), _marker: PhantomData }, tag)
}
#[inline]
unsafe fn from_marked_ptr(
marked: crate::pointer::MarkedPtr<Self::Item, Self::MarkBits>
) -> Self
{
debug_assert!(!marked.is_null());
Self { inner: MarkedNonNull::new_unchecked(marked), _marker: PhantomData}
}
#[inline]
unsafe fn from_marked_non_null(
marked: crate::pointer::MarkedNonNull<Self::Item, Self::MarkBits>
) -> Self
{
Self { inner: marked, _marker: PhantomData }
}
};
}
macro_rules! impl_inherent {
($self:ident) => {
/// Creates a `None` variant for an [`Option<Self>`][Option].
///
/// This is useful for calls to [`store`][store], [`swap`][swap] or
/// [`compare_exchange_*`][compare_exchange], when a `null` pointer
/// needs to be inserted.
/// These methods accept values of various non-nullable pointer types
/// ([`Shared`][Shared], [`Owned`][Owned], [`Unlinked`][Unlinked] and
/// [`Unprotected`][Unprotected]) and [`Option`] types thereof as
/// argument.
/// However, the compiler is usually not able to infer the concrete
/// type, when a [`None`] is inserted, and this function is intended for
/// these cases.
///
/// [store]: crate::Atomic::store
/// [swap]: crate::Atomic::swap
/// [compare_exchange]: crate::Atomic::compare_exchange
/// [Shared]: crate::Shared
/// [Owned]: crate::Owned
/// [Unlinked]: crate::Unlinked
/// [Unprotected]: crate::Unprotected
///
/// # Example
///
/// ```
/// use std::sync::atomic::Ordering;
///
/// type Atomic<T> = reclaim::leak::Atomic<T, reclaim::typenum::U0>;
/// type Owned<T> = reclaim::leak::Owned<T, reclaim::typenum::U0>;
/// type Unlinked<T> = reclaim::leak::Unlinked<T, reclaim::typenum::U0>;
///
/// let atomic = Atomic::new(1);
/// let swap = atomic.swap(Owned::none(), Ordering::Relaxed).unwrap();
///
/// assert_eq!(swap.as_ref(), &1);
/// unsafe { Unlinked::retire(swap) }; // leaks memory
/// ```
#[inline]
pub fn none() -> Option<Self> {
None
}
/// Creates an unmarked [`Null`][crate::pointer::Marked::Null] variant
/// for a [`Marked<Self>`][crate::pointer::Marked].
#[inline]
pub fn null() -> crate::pointer::Marked<Self> {
Marked::Null(0)
}
/// Creates a marked [`Null`][crate::pointer::Marked::Null] variant for
/// a [`Marked<Self>`][crate::pointer::Marked] with the given `tag`.
#[inline]
pub fn null_with_tag(tag: usize) -> crate::pointer::Marked<Self> {
Marked::Null(tag)
}
/// Consumes the given `Self` and returns the same value but with the
/// specified `tag`.
///
/// Any previous tag is overwritten.
#[inline]
pub fn compose($self: Self, tag: usize) -> Self {
let inner = $self.inner;
core::mem::forget($self);
Self { inner: inner.with_tag(tag), _marker: PhantomData }
}
};
}