feat: implement asynchronous channel support with tokio integration

src/async_channel.rs

@@ -0,0 +1,196 @@
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
+
+use crate::asynchronous::traits::{AsyncChannelReceiver, AsyncChannelSender};
+use crate::error::Error;
+use crate::types::{ChannelState, Request, Response, ValueSource};
+
+/// The consumer side of the channel that requests values asynchronously.
+pub struct AsyncSucker<T, ST, SR>
+where
+    ST: AsyncChannelSender<Request>,
+    SR: AsyncChannelReceiver<Response<T>>,
+{
+    request_tx: ST,
+    response_rx: SR,
+    closed: AtomicBool,
+    _phantom: std::marker::PhantomData<T>,
+}
+
+impl<T, ST, SR> AsyncSucker<T, ST, SR>
+where
+    ST: AsyncChannelSender<Request>,
+    SR: AsyncChannelReceiver<Response<T>>,
+{
+    pub(crate) fn new(request_tx: ST, response_rx: SR) -> Self {
+        Self {
+            request_tx,
+            response_rx,
+            closed: AtomicBool::new(false),
+            _phantom: std::marker::PhantomData,
+        }
+    }
+}
+
+/// The producer side of the channel that provides values asynchronously.
+pub struct AsyncSourcer<T, SR, ST>
+where
+    SR: AsyncChannelReceiver<Request>,
+    ST: AsyncChannelSender<Response<T>>,
+{
+    request_rx: SR,
+    response_tx: ST,
+    state: ChannelState<T>,
+    _phantom: std::marker::PhantomData<T>,
+}
+
+impl<T, SR, ST> AsyncSourcer<T, SR, ST>
+where
+    SR: AsyncChannelReceiver<Request>,
+    ST: AsyncChannelSender<Response<T>>,
+{
+    pub(crate) fn new(request_rx: SR, response_tx: ST, state: ChannelState<T>) -> Self {
+        Self {
+            request_rx,
+            response_tx,
+            state,
+            _phantom: std::marker::PhantomData,
+        }
+    }
+}
+
+impl<T, SR, ST> AsyncSourcer<T, SR, ST>
+where
+    T: Send + 'static,
+    SR: AsyncChannelReceiver<Request>,
+    ST: AsyncChannelSender<Response<T>>,
+{
+    pub fn set_static(&self, val: T) -> Result<(), Error>
+    where
+        T: Clone,
+    {
+        self.state.swap(Arc::new(ValueSource::Static {
+            val,
+            clone: T::clone,
+        }));
+        Ok(())
+    }
+
+    pub fn set<F>(&self, closure: F) -> Result<(), Error>
+    where
+        F: Fn() -> T + Send + Sync + 'static,
+    {
+        self.state
+            .swap(Arc::new(ValueSource::Dynamic(Box::new(closure))));
+        Ok(())
+    }
+
+    pub fn set_mut<F>(&self, closure: F) -> Result<(), Error>
+    where
+        F: FnMut() -> T + Send + Sync + 'static,
+    {
+        self.state
+            .swap(Arc::new(ValueSource::DynamicMut(Mutex::new(Box::new(
+                closure,
+            )))));
+        Ok(())
+    }
+
+    pub fn close(&self) -> Result<(), Error> {
+        self.state.swap(Arc::new(ValueSource::Cleared));
+        Ok(())
+    }
+
+    pub async fn run(self) -> Result<(), Error> {
+        loop {
+            match self.request_rx.recv().await {
+                Ok(Request::GetValue) => {
+                    let response = self.handle_get_value()?;
+                    if self.response_tx.send(response).await.is_err() {
+                        break;
+                    }
+                }
+                Ok(Request::Close) => {
+                    self.close()?;
+                    break;
+                }
+                Err(_) => break,
+            }
+        }
+        Ok(())
+    }
+
+    fn handle_get_value(&self) -> Result<Response<T>, Error> {
+        let state = self.state.load();
+
+        match &**state {
+            ValueSource::Static { val, clone } => {
+                let value = self.execute_closure_safely(&mut || clone(val));
+                match value {
+                    Ok(v) => Ok(Response::Value(v)),
+                    Err(_) => Ok(Response::NoSource),
+                }
+            }
+            ValueSource::Dynamic(closure) => {
+                let value = self.execute_closure_safely(&mut || closure());
+                match value {
+                    Ok(v) => Ok(Response::Value(v)),
+                    Err(_) => Ok(Response::NoSource),
+                }
+            }
+            ValueSource::DynamicMut(closure) => {
+                let mut closure = closure.lock().unwrap();
+                let value = self.execute_closure_safely(&mut *closure);
+                match value {
+                    Ok(v) => Ok(Response::Value(v)),
+                    Err(_) => Ok(Response::NoSource),
+                }
+            }
+            ValueSource::None => Ok(Response::NoSource),
+            ValueSource::Cleared => Ok(Response::Closed),
+        }
+    }
+
+    fn execute_closure_safely(
+        &self,
+        closure: &mut dyn FnMut() -> T,
+    ) -> Result<T, Box<dyn std::any::Any + Send>> {
+        std::panic::catch_unwind(std::panic::AssertUnwindSafe(closure))
+    }
+}
+
+impl<T, ST, SR> AsyncSucker<T, ST, SR>
+where
+    ST: AsyncChannelSender<Request>,
+    SR: AsyncChannelReceiver<Response<T>>,
+{
+    pub async fn get(&self) -> Result<T, Error> {
+        if self.closed.load(Ordering::Acquire) {
+            return Err(Error::ChannelClosed);
+        }
+
+        self.request_tx
+            .send(Request::GetValue)
+            .await
+            .map_err(|_| Error::ProducerDisconnected)?;
+
+        match self.response_rx.recv().await {
+            Ok(Response::Value(value)) => Ok(value),
+            Ok(Response::NoSource) => Err(Error::NoSource),
+            Ok(Response::Closed) => Err(Error::ChannelClosed),
+            Err(_) => Err(Error::ProducerDisconnected),
+        }
+    }
+
+    pub async fn is_closed(&self) -> bool {
+        self.request_tx.send(Request::GetValue).await.is_err()
+    }
+
+    pub async fn close(&self) -> Result<(), Error> {
+        self.closed.store(true, Ordering::Release);
+        self.request_tx
+            .send(Request::Close)
+            .await
+            .map_err(|_| Error::ProducerDisconnected)
+    }
+}