use crate::shared_pointer::kind::SharedPointerKind;
use alloc::boxed::Box;
use alloc::sync::Arc;
use core::fmt;
use core::fmt::Debug;
use core::fmt::Formatter;
use core::mem;
use core::mem::ManuallyDrop;
use core::ops::Deref;
use core::ops::DerefMut;
use core::ptr;
type UntypedArc = Arc<()>;
pub struct ArcK {
inner: ManuallyDrop<UntypedArc>,
}
impl ArcK {
#[inline(always)]
fn new_from_inner<T>(arc: Arc<T>) -> ArcK {
ArcK { inner: ManuallyDrop::new(unsafe { mem::transmute(arc) }) }
}
#[inline(always)]
unsafe fn take_inner<T>(self) -> Arc<T> {
let arc: UntypedArc = ManuallyDrop::into_inner(self.inner);
mem::transmute(arc)
}
#[inline(always)]
unsafe fn as_inner_ref<T>(&self) -> &Arc<T> {
let arc_t: *const Arc<T> =
(self.inner.deref() as *const UntypedArc).cast::<alloc::sync::Arc<T>>();
let _ = mem::transmute::<UntypedArc, Arc<T>>;
&*arc_t
}
#[inline(always)]
unsafe fn as_inner_mut<T>(&mut self) -> &mut Arc<T> {
let arc_t: *mut Arc<T> =
(self.inner.deref_mut() as *mut UntypedArc).cast::<alloc::sync::Arc<T>>();
&mut *arc_t
}
}
unsafe impl SharedPointerKind for ArcK {
#[inline(always)]
fn new<T>(v: T) -> ArcK {
ArcK::new_from_inner(Arc::new(v))
}
#[inline(always)]
fn from_box<T>(v: Box<T>) -> ArcK {
ArcK::new_from_inner::<T>(Arc::from(v))
}
#[inline(always)]
unsafe fn as_ptr<T>(&self) -> *const T {
Arc::as_ptr(self.as_inner_ref())
}
#[inline(always)]
unsafe fn deref<T>(&self) -> &T {
self.as_inner_ref::<T>().as_ref()
}
#[inline(always)]
unsafe fn try_unwrap<T>(self) -> Result<T, ArcK> {
Arc::try_unwrap(self.take_inner()).map_err(ArcK::new_from_inner)
}
#[inline(always)]
unsafe fn get_mut<T>(&mut self) -> Option<&mut T> {
Arc::get_mut(self.as_inner_mut())
}
#[inline(always)]
unsafe fn make_mut<T: Clone>(&mut self) -> &mut T {
Arc::make_mut(self.as_inner_mut())
}
#[inline(always)]
unsafe fn strong_count<T>(&self) -> usize {
Arc::strong_count(self.as_inner_ref::<T>())
}
#[inline(always)]
unsafe fn clone<T>(&self) -> ArcK {
ArcK { inner: ManuallyDrop::new(Arc::clone(self.as_inner_ref())) }
}
#[inline(always)]
unsafe fn drop<T>(&mut self) {
ptr::drop_in_place::<Arc<T>>(self.as_inner_mut());
}
}
impl Debug for ArcK {
#[inline(always)]
fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
f.write_str("ArcK")
}
}
#[cfg(test)]
mod test;