109 lines
3.7 KiB
Rust
109 lines
3.7 KiB
Rust
use super::super::main_thread::MainThreadMarker;
|
|
use super::{channel, AsyncReceiver, AsyncSender, Wrapper};
|
|
use std::{
|
|
cell::Ref,
|
|
sync::{Arc, Condvar, Mutex},
|
|
};
|
|
|
|
pub struct Dispatcher<T: 'static>(Wrapper<true, T, AsyncSender<Closure<T>>, Closure<T>>);
|
|
|
|
struct Closure<T>(Box<dyn FnOnce(&T) + Send>);
|
|
|
|
impl<T> Dispatcher<T> {
|
|
#[track_caller]
|
|
pub fn new(main_thread: MainThreadMarker, value: T) -> Option<(Self, DispatchRunner<T>)> {
|
|
let (sender, receiver) = channel::<Closure<T>>();
|
|
|
|
Wrapper::new(
|
|
main_thread,
|
|
value,
|
|
|value, Closure(closure)| {
|
|
// SAFETY: The given `Closure` here isn't really `'static`, so we shouldn't do anything
|
|
// funny with it here. See `Self::queue()`.
|
|
closure(value.borrow().as_ref().unwrap())
|
|
},
|
|
{
|
|
let receiver = receiver.clone();
|
|
move |value| async move {
|
|
while let Ok(Closure(closure)) = receiver.next().await {
|
|
// SAFETY: The given `Closure` here isn't really `'static`, so we shouldn't do anything
|
|
// funny with it here. See `Self::queue()`.
|
|
closure(value.borrow().as_ref().unwrap())
|
|
}
|
|
}
|
|
},
|
|
sender,
|
|
|sender, closure| {
|
|
// SAFETY: The given `Closure` here isn't really `'static`, so we shouldn't do anything
|
|
// funny with it here. See `Self::queue()`.
|
|
sender.send(closure).unwrap()
|
|
},
|
|
)
|
|
.map(|wrapper| (Self(wrapper.clone()), DispatchRunner { wrapper, receiver }))
|
|
}
|
|
|
|
pub fn value(&self) -> Option<Ref<'_, T>> {
|
|
self.0.value()
|
|
}
|
|
|
|
pub fn dispatch(&self, f: impl 'static + FnOnce(&T) + Send) {
|
|
if let Some(value) = self.0.value() {
|
|
f(&value)
|
|
} else {
|
|
self.0.send(Closure(Box::new(f)))
|
|
}
|
|
}
|
|
|
|
pub fn queue<R: Send>(&self, f: impl FnOnce(&T) -> R + Send) -> R {
|
|
if let Some(value) = self.0.value() {
|
|
f(&value)
|
|
} else {
|
|
let pair = Arc::new((Mutex::new(None), Condvar::new()));
|
|
let closure = Box::new({
|
|
let pair = pair.clone();
|
|
move |value: &T| {
|
|
*pair.0.lock().unwrap() = Some(f(value));
|
|
pair.1.notify_one();
|
|
}
|
|
}) as Box<dyn FnOnce(&T) + Send>;
|
|
// SAFETY: The `transmute` is necessary because `Closure` requires `'static`. This is
|
|
// safe because this function won't return until `f` has finished executing. See
|
|
// `Self::new()`.
|
|
let closure = Closure(unsafe { std::mem::transmute(closure) });
|
|
|
|
self.0.send(closure);
|
|
|
|
let mut started = pair.0.lock().unwrap();
|
|
|
|
while started.is_none() {
|
|
started = pair.1.wait(started).unwrap();
|
|
}
|
|
|
|
started.take().unwrap()
|
|
}
|
|
}
|
|
}
|
|
|
|
pub struct DispatchRunner<T: 'static> {
|
|
wrapper: Wrapper<true, T, AsyncSender<Closure<T>>, Closure<T>>,
|
|
receiver: AsyncReceiver<Closure<T>>,
|
|
}
|
|
|
|
impl<T> DispatchRunner<T> {
|
|
pub fn run(&self) {
|
|
while let Some(Closure(closure)) = self
|
|
.receiver
|
|
.try_recv()
|
|
.expect("should only be closed when `Dispatcher` is dropped")
|
|
{
|
|
// SAFETY: The given `Closure` here isn't really `'static`, so we shouldn't do anything
|
|
// funny with it here. See `Self::queue()`.
|
|
closure(
|
|
&self
|
|
.wrapper
|
|
.value()
|
|
.expect("don't call this outside the main thread"),
|
|
)
|
|
}
|
|
}
|
|
}
|