tasks initial impl (still working on task_on trait method)

src/default/task.rs

@@ -0,0 +1,85 @@
+use iris_core::HasState;
+use std::{
+    pin::Pin,
+    sync::{
+        Arc,
+        mpsc::{Receiver as SyncReceiver, Sender as SyncSender, channel as sync_channel},
+    },
+};
+use tokio::{
+    runtime::Runtime,
+    sync::mpsc::{
+        UnboundedReceiver as AsyncReceiver, UnboundedSender as AsyncSender,
+        unbounded_channel as async_channel,
+    },
+};
+use winit::window::Window;
+
+pub type TaskMsgSender<Rsc> = SyncSender<Box<dyn TaskUpdate<Rsc>>>;
+pub type TaskMsgReceiver<Rsc> = SyncReceiver<Box<dyn TaskUpdate<Rsc>>>;
+
+pub trait TaskUpdate<Rsc: HasState>: FnOnce(&mut Rsc::State, &mut Rsc) + Send {}
+impl<F: FnOnce(&mut Rsc::State, &mut Rsc) + Send, Rsc: HasState> TaskUpdate<Rsc> for F {}
+
+pub struct Tasks<Rsc: HasState> {
+    start: AsyncSender<BoxTask>,
+    window: Arc<Window>,
+    msg_send: SyncSender<Box<dyn TaskUpdate<Rsc>>>,
+}
+
+pub struct TaskCtx<Rsc: HasState> {
+    send: TaskMsgSender<Rsc>,
+}
+
+impl<Rsc: HasState> TaskCtx<Rsc> {
+    pub fn update(&mut self, f: impl TaskUpdate<Rsc> + 'static) {
+        let _ = self.send.send(Box::new(f));
+    }
+}
+impl<Rsc: HasState + 'static> TaskCtx<Rsc> {
+    fn new(send: TaskMsgSender<Rsc>) -> Self {
+        Self { send }
+    }
+}
+
+type BoxTask = Pin<Box<dyn Future<Output = ()> + Send>>;
+
+impl<Rsc: HasState> Tasks<Rsc> {
+    pub fn init(window: Arc<Window>) -> (Self, TaskMsgReceiver<Rsc>) {
+        let (start, start_recv) = async_channel();
+        let (msgs, msgs_recv) = sync_channel();
+        std::thread::spawn(|| {
+            let rt = Runtime::new().unwrap();
+            rt.block_on(listen(start_recv))
+        });
+        (
+            Self {
+                start,
+                msg_send: msgs,
+                window,
+            },
+            msgs_recv,
+        )
+    }
+
+    pub fn spawn<F: for<'a> AsyncFnOnce(&'a mut TaskCtx<Rsc>) + 'static + std::marker::Send>(
+        &mut self,
+        task: F,
+    ) where
+        for<'a> <F as AsyncFnOnce<(&'a mut TaskCtx<Rsc>,)>>::CallOnceFuture: Send,
+    {
+        let send = self.msg_send.clone();
+        let window = self.window.clone();
+        let _ = self.start.send(Box::pin(async move {
+            let mut ctx = TaskCtx::new(send);
+            task(&mut ctx).await;
+            window.request_redraw();
+        }));
+    }
+}
+
+async fn listen(mut recv: AsyncReceiver<BoxTask>) {
+    while let Some(task) = recv.recv().await {
+        tokio::spawn(task);
+    }
+}