use std::{cell::UnsafeCell, fmt, rc::Rc, rc::Weak};
pub(super) struct Cell<T> {
inner: Rc<UnsafeCell<T>>,
}
impl<T> Clone for Cell<T> {
fn clone(&self) -> Self {
Self {
inner: self.inner.clone(),
}
}
}
impl<T: fmt::Debug> fmt::Debug for Cell<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.fmt(f)
}
}
impl<T> Cell<T> {
pub(super) fn new(inner: T) -> Self {
Self {
inner: Rc::new(UnsafeCell::new(inner)),
}
}
pub(super) fn strong_count(&self) -> usize {
Rc::strong_count(&self.inner)
}
pub(super) fn get_ref(&self) -> &T {
unsafe { &*self.inner.as_ref().get() }
}
#[allow(clippy::mut_from_ref)]
pub(super) fn get_mut(&self) -> &mut T {
unsafe { &mut *self.inner.as_ref().get() }
}
pub(super) fn downgrade(&self) -> WeakCell<T> {
WeakCell {
inner: Rc::downgrade(&self.inner),
}
}
}
pub(super) struct WeakCell<T> {
inner: Weak<UnsafeCell<T>>,
}
impl<T> Clone for WeakCell<T> {
fn clone(&self) -> Self {
Self {
inner: self.inner.clone(),
}
}
}
impl<T> WeakCell<T> {
pub(super) fn upgrade(&self) -> Option<Cell<T>> {
self.inner.upgrade().map(|inner| Cell { inner })
}
}