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use std::ops::Deref;
use std::rc::Rc;
use std::sync::Arc;
/// A convenience trait to abstract over Arc<T> and Rc<T> APIs.
pub trait RefCounted<T>: Sized + Clone + Deref<Target = T> + From<T> {
/// Returns a mutable reference to the contained value if the wrapper
/// has a single, unique, reference.
///
/// Returns `None` if this is not the only reference to the data.
fn get_mut(&mut self) -> Option<&mut T>;
/// Make a mutable reference into the given implementation. If the
/// implementation has more than one strong reference, or any weak
/// references, the inner data is cloned.
///
/// This is also referred to as a copy-on-write.
fn make_mut(&mut self) -> &mut T
where
T: Clone;
}
impl<T> RefCounted<T> for Rc<T> {
fn get_mut(&mut self) -> Option<&mut T> {
Rc::get_mut(self)
}
fn make_mut(&mut self) -> &mut T
where
T: Clone,
{
Rc::make_mut(self)
}
}
impl<T> RefCounted<T> for Arc<T> {
fn get_mut(&mut self) -> Option<&mut T> {
Arc::get_mut(self)
}
fn make_mut(&mut self) -> &mut T
where
T: Clone,
{
Arc::make_mut(self)
}
}