use std::{cell::RefCell, collections::VecDeque, rc::Rc};
pub struct DispatchData<'a> {
data: &'a mut dyn std::any::Any,
}
impl<'a> DispatchData<'a> {
pub fn get<T: std::any::Any>(&mut self) -> Option<&mut T> {
self.data.downcast_mut()
}
pub fn wrap<T: std::any::Any>(data: &'a mut T) -> DispatchData<'a> {
DispatchData { data }
}
pub fn reborrow(&mut self) -> DispatchData {
DispatchData {
data: &mut *self.data,
}
}
}
struct Inner<E, F: ?Sized> {
pending: RefCell<VecDeque<E>>,
cb: RefCell<F>,
}
type DynInner<E> = Inner<E, dyn FnMut(E, &Filter<E>, DispatchData<'_>)>;
pub struct Filter<E> {
inner: Rc<DynInner<E>>,
}
impl<E> Clone for Filter<E> {
fn clone(&self) -> Filter<E> {
Filter {
inner: self.inner.clone(),
}
}
}
impl<E> Filter<E> {
pub fn new<F: FnMut(E, &Filter<E>, DispatchData<'_>) + 'static>(f: F) -> Filter<E> {
Filter {
inner: Rc::new(Inner {
pending: RefCell::new(VecDeque::new()),
cb: RefCell::new(f),
}),
}
}
pub fn send(&self, evt: E, mut data: DispatchData) {
if let Ok(mut guard) = self.inner.cb.try_borrow_mut() {
(&mut *guard)(evt, self, data.reborrow());
while let Some(evt) = self.inner.pending.borrow_mut().pop_front() {
(&mut *guard)(evt, self, data.reborrow());
}
} else {
self.inner.pending.borrow_mut().push_back(evt);
}
}
}