embassy/channel: switch to use MutexKind

2 files changed, 69 insertions, 126 deletions

diff --git a/embassy/src/channel/mpsc.rs b/embassy/src/channel/mpsc.rs
index 3585b8039..9a57c0b19 100644
--- a/embassy/src/channel/mpsc.rs
+++ b/embassy/src/channel/mpsc.rs
@@ -37,7 +37,7 @@
 //!
 //! This channel and its associated types were derived from https://docs.rs/tokio/0.1.22/tokio/sync/mpsc/fn.channel.html
 
-use core::cell::UnsafeCell;
+use core::cell::RefCell;
 use core::fmt;
 use core::pin::Pin;
 use core::task::Context;
@@ -47,7 +47,8 @@ use core::task::Waker;
 use futures::Future;
 use heapless::Deque;
 
-use crate::blocking_mutex::{CriticalSectionMutex, Mutex, NoopMutex, ThreadModeMutex};
+use crate::blocking_mutex::kind::MutexKind;
+use crate::blocking_mutex::Mutex;
 use crate::waitqueue::WakerRegistration;
 
 /// Send values to the associated `Receiver`.
@@ -55,35 +56,19 @@ use crate::waitqueue::WakerRegistration;
 /// Instances are created by the [`split`](split) function.
 pub struct Sender<'ch, M, T, const N: usize>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    channel_cell: &'ch UnsafeCell<ChannelCell<M, T, N>>,
+    channel: &'ch Channel<M, T, N>,
 }
 
-// Safe to pass the sender around
-unsafe impl<'ch, M, T, const N: usize> Send for Sender<'ch, M, T, N> where M: Mutex<Data = ()> + Sync
-{}
-unsafe impl<'ch, M, T, const N: usize> Sync for Sender<'ch, M, T, N> where M: Mutex<Data = ()> + Sync
-{}
-
 /// Receive values from the associated `Sender`.
 ///
 /// Instances are created by the [`split`](split) function.
 pub struct Receiver<'ch, M, T, const N: usize>
 where
-    M: Mutex<Data = ()>,
-{
-    channel_cell: &'ch UnsafeCell<ChannelCell<M, T, N>>,
-}
-
-// Safe to pass the receiver around
-unsafe impl<'ch, M, T, const N: usize> Send for Receiver<'ch, M, T, N> where
-    M: Mutex<Data = ()> + Sync
-{
-}
-unsafe impl<'ch, M, T, const N: usize> Sync for Receiver<'ch, M, T, N> where
-    M: Mutex<Data = ()> + Sync
+    M: MutexKind,
 {
+    channel: &'ch Channel<M, T, N>,
 }
 
 /// Splits a bounded mpsc channel into a `Sender` and `Receiver`.
@@ -114,15 +99,11 @@ pub fn split<M, T, const N: usize>(
     channel: &mut Channel<M, T, N>,
 ) -> (Sender<M, T, N>, Receiver<M, T, N>)
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    let sender = Sender {
-        channel_cell: &channel.channel_cell,
-    };
-    let receiver = Receiver {
-        channel_cell: &channel.channel_cell,
-    };
-    Channel::lock(&channel.channel_cell, |c| {
+    let sender = Sender { channel };
+    let receiver = Receiver { channel };
+    channel.lock(|c| {
         c.register_receiver();
         c.register_sender();
     });
@@ -131,7 +112,7 @@ where
 
 impl<'ch, M, T, const N: usize> Receiver<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     /// Receives the next value for this receiver.
     ///
@@ -151,7 +132,7 @@ where
     /// [`close`]: Self::close
     pub fn recv<'m>(&'m mut self) -> RecvFuture<'m, M, T, N> {
         RecvFuture {
-            channel_cell: self.channel_cell,
+            channel: self.channel,
         }
     }
 
@@ -160,7 +141,7 @@ where
     /// This method will either receive a message from the channel immediately or return an error
     /// if the channel is empty.
     pub fn try_recv(&self) -> Result<T, TryRecvError> {
-        Channel::lock(self.channel_cell, |c| c.try_recv())
+        self.channel.lock(|c| c.try_recv())
     }
 
     /// Closes the receiving half of a channel without dropping it.
@@ -174,56 +155,45 @@ where
     /// until those are released.
     ///
     pub fn close(&mut self) {
-        Channel::lock(self.channel_cell, |c| c.close())
+        self.channel.lock(|c| c.close())
     }
 }
 
 impl<'ch, M, T, const N: usize> Drop for Receiver<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     fn drop(&mut self) {
-        Channel::lock(self.channel_cell, |c| c.deregister_receiver())
+        self.channel.lock(|c| c.deregister_receiver())
     }
 }
 
 pub struct RecvFuture<'ch, M, T, const N: usize>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    channel_cell: &'ch UnsafeCell<ChannelCell<M, T, N>>,
+    channel: &'ch Channel<M, T, N>,
 }
 
 impl<'ch, M, T, const N: usize> Future for RecvFuture<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     type Output = Option<T>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> {
-        Channel::lock(self.channel_cell, |c| {
-            match c.try_recv_with_context(Some(cx)) {
+        self.channel
+            .lock(|c| match c.try_recv_with_context(Some(cx)) {
                 Ok(v) => Poll::Ready(Some(v)),
                 Err(TryRecvError::Closed) => Poll::Ready(None),
                 Err(TryRecvError::Empty) => Poll::Pending,
-            }
-        })
+            })
     }
 }
 
-// Safe to pass the receive future around since it locks channel whenever polled
-unsafe impl<'ch, M, T, const N: usize> Send for RecvFuture<'ch, M, T, N> where
-    M: Mutex<Data = ()> + Sync
-{
-}
-unsafe impl<'ch, M, T, const N: usize> Sync for RecvFuture<'ch, M, T, N> where
-    M: Mutex<Data = ()> + Sync
-{
-}
-
 impl<'ch, M, T, const N: usize> Sender<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     /// Sends a value, waiting until there is capacity.
     ///
@@ -245,7 +215,7 @@ where
     /// [`Receiver`]: Receiver
     pub fn send(&self, message: T) -> SendFuture<'ch, M, T, N> {
         SendFuture {
-            sender: self.clone(),
+            channel: self.channel,
             message: Some(message),
         }
     }
@@ -271,7 +241,7 @@ where
     /// [`channel`]: channel
     /// [`close`]: Receiver::close
     pub fn try_send(&self, message: T) -> Result<(), TrySendError<T>> {
-        Channel::lock(self.channel_cell, |c| c.try_send(message))
+        self.channel.lock(|c| c.try_send(message))
     }
 
     /// Completes when the receiver has dropped.
@@ -280,7 +250,7 @@ where
     /// values is canceled and immediately stop doing work.
     pub async fn closed(&self) {
         CloseFuture {
-            sender: self.clone(),
+            channel: self.channel,
         }
         .await
     }
@@ -292,29 +262,27 @@ where
     /// [`Receiver`]: crate::sync::mpsc::Receiver
     /// [`Receiver::close`]: crate::sync::mpsc::Receiver::close
     pub fn is_closed(&self) -> bool {
-        Channel::lock(self.channel_cell, |c| c.is_closed())
+        self.channel.lock(|c| c.is_closed())
     }
 }
 
 pub struct SendFuture<'ch, M, T, const N: usize>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    sender: Sender<'ch, M, T, N>,
+    channel: &'ch Channel<M, T, N>,
     message: Option<T>,
 }
 
 impl<'ch, M, T, const N: usize> Future for SendFuture<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     type Output = Result<(), SendError<T>>;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         match self.message.take() {
-            Some(m) => match Channel::lock(self.sender.channel_cell, |c| {
-                c.try_send_with_context(m, Some(cx))
-            }) {
+            Some(m) => match self.channel.lock(|c| c.try_send_with_context(m, Some(cx))) {
                 Ok(..) => Poll::Ready(Ok(())),
                 Err(TrySendError::Closed(m)) => Poll::Ready(Err(SendError(m))),
                 Err(TrySendError::Full(m)) => {
@@ -327,25 +295,23 @@ where
     }
 }
 
-impl<'ch, M, T, const N: usize> Unpin for SendFuture<'ch, M, T, N> where M: Mutex<Data = ()> {}
+impl<'ch, M, T, const N: usize> Unpin for SendFuture<'ch, M, T, N> where M: MutexKind {}
 
 struct CloseFuture<'ch, M, T, const N: usize>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    sender: Sender<'ch, M, T, N>,
+    channel: &'ch Channel<M, T, N>,
 }
 
 impl<'ch, M, T, const N: usize> Future for CloseFuture<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     type Output = ();
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        if Channel::lock(self.sender.channel_cell, |c| {
-            c.is_closed_with_context(Some(cx))
-        }) {
+        if self.channel.lock(|c| c.is_closed_with_context(Some(cx))) {
             Poll::Ready(())
         } else {
             Poll::Pending
@@ -355,22 +321,21 @@ where
 
 impl<'ch, M, T, const N: usize> Drop for Sender<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     fn drop(&mut self) {
-        Channel::lock(self.channel_cell, |c| c.deregister_sender())
+        self.channel.lock(|c| c.deregister_sender())
     }
 }
 
 impl<'ch, M, T, const N: usize> Clone for Sender<'ch, M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    #[allow(clippy::clone_double_ref)]
     fn clone(&self) -> Self {
-        Channel::lock(self.channel_cell, |c| c.register_sender());
+        self.channel.lock(|c| c.register_sender());
         Sender {
-            channel_cell: self.channel_cell.clone(),
+            channel: self.channel,
         }
     }
 }
@@ -581,59 +546,35 @@ impl<T, const N: usize> ChannelState<T, N> {
 /// All data sent will become available in the same order as it was sent.
 pub struct Channel<M, T, const N: usize>
 where
-    M: Mutex<Data = ()>,
-{
-    channel_cell: UnsafeCell<ChannelCell<M, T, N>>,
-}
-
-struct ChannelCell<M, T, const N: usize>
-where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
-    mutex: M,
-    state: ChannelState<T, N>,
+    inner: M::Mutex<RefCell<ChannelState<T, N>>>,
 }
 
-pub type WithCriticalSections = CriticalSectionMutex<()>;
-
-pub type WithThreadModeOnly = ThreadModeMutex<()>;
-
-pub type WithNoThreads = NoopMutex<()>;
-
 impl<M, T, const N: usize> Channel<M, T, N>
 where
-    M: Mutex<Data = ()>,
+    M: MutexKind,
 {
     /// Establish a new bounded channel. For example, to create one with a NoopMutex:
     ///
     /// ```
     /// use embassy::channel::mpsc;
-    /// use embassy::channel::mpsc::{Channel, WithNoThreads};
+    /// use embassy::blocking_mutex::kind::Noop;
+    /// use embassy::channel::mpsc::Channel;
     ///
     /// // Declare a bounded channel of 3 u32s.
-    /// let mut channel = Channel::<WithNoThreads, u32, 3>::new();
+    /// let mut channel = Channel::<Noop, u32, 3>::new();
     /// // once we have a channel, obtain its sender and receiver
     /// let (sender, receiver) = mpsc::split(&mut channel);
     /// ```
     pub fn new() -> Self {
-        let mutex = M::new(());
-        let state = ChannelState::new();
-        let channel_cell = ChannelCell { mutex, state };
-        Channel {
-            channel_cell: UnsafeCell::new(channel_cell),
+        Self {
+            inner: M::Mutex::new(RefCell::new(ChannelState::new())),
         }
     }
 
-    fn lock<R>(
-        channel_cell: &UnsafeCell<ChannelCell<M, T, N>>,
-        f: impl FnOnce(&mut ChannelState<T, N>) -> R,
-    ) -> R {
-        unsafe {
-            let channel_cell = &mut *(channel_cell.get());
-            let mutex = &mut channel_cell.mutex;
-            let mut state = &mut channel_cell.state;
-            mutex.lock(|_| f(&mut state))
-        }
+    fn lock<R>(&self, f: impl FnOnce(&mut ChannelState<T, N>) -> R) -> R {
+        self.inner.lock(|rc| f(&mut *rc.borrow_mut()))
     }
 }
 
@@ -645,6 +586,7 @@ mod tests {
     use futures_executor::ThreadPool;
     use futures_timer::Delay;
 
+    use crate::blocking_mutex::kind::{CriticalSection, Noop};
     use crate::util::Forever;
 
     use super::*;
@@ -713,7 +655,7 @@ mod tests {
 
     #[test]
     fn simple_send_and_receive() {
-        let mut c = Channel::<WithNoThreads, u32, 3>::new();
+        let mut c = Channel::<Noop, u32, 3>::new();
         let (s, r) = split(&mut c);
         assert!(s.clone().try_send(1).is_ok());
         assert_eq!(r.try_recv().unwrap(), 1);
@@ -721,7 +663,7 @@ mod tests {
 
     #[test]
     fn should_close_without_sender() {
-        let mut c = Channel::<WithNoThreads, u32, 3>::new();
+        let mut c = Channel::<Noop, u32, 3>::new();
         let (s, r) = split(&mut c);
         drop(s);
         match r.try_recv() {
@@ -732,7 +674,7 @@ mod tests {
 
     #[test]
     fn should_close_once_drained() {
-        let mut c = Channel::<WithNoThreads, u32, 3>::new();
+        let mut c = Channel::<Noop, u32, 3>::new();
         let (s, r) = split(&mut c);
         assert!(s.try_send(1).is_ok());
         drop(s);
@@ -745,7 +687,7 @@ mod tests {
 
     #[test]
     fn should_reject_send_when_receiver_dropped() {
-        let mut c = Channel::<WithNoThreads, u32, 3>::new();
+        let mut c = Channel::<Noop, u32, 3>::new();
         let (s, r) = split(&mut c);
         drop(r);
         match s.try_send(1) {
@@ -756,7 +698,7 @@ mod tests {
 
     #[test]
     fn should_reject_send_when_channel_closed() {
-        let mut c = Channel::<WithNoThreads, u32, 3>::new();
+        let mut c = Channel::<Noop, u32, 3>::new();
         let (s, mut r) = split(&mut c);
         assert!(s.try_send(1).is_ok());
         r.close();
@@ -772,7 +714,7 @@ mod tests {
     async fn receiver_closes_when_sender_dropped_async() {
         let executor = ThreadPool::new().unwrap();
 
-        static CHANNEL: Forever<Channel<WithCriticalSections, u32, 3>> = Forever::new();
+        static CHANNEL: Forever<Channel<CriticalSection, u32, 3>> = Forever::new();
         let c = CHANNEL.put(Channel::new());
         let (s, mut r) = split(c);
         assert!(executor
@@ -787,7 +729,7 @@ mod tests {
     async fn receiver_receives_given_try_send_async() {
         let executor = ThreadPool::new().unwrap();
 
-        static CHANNEL: Forever<Channel<WithCriticalSections, u32, 3>> = Forever::new();
+        static CHANNEL: Forever<Channel<CriticalSection, u32, 3>> = Forever::new();
         let c = CHANNEL.put(Channel::new());
         let (s, mut r) = split(c);
         assert!(executor
@@ -800,7 +742,7 @@ mod tests {
 
     #[futures_test::test]
     async fn sender_send_completes_if_capacity() {
-        let mut c = Channel::<WithCriticalSections, u32, 1>::new();
+        let mut c = Channel::<CriticalSection, u32, 1>::new();
         let (s, mut r) = split(&mut c);
         assert!(s.send(1).await.is_ok());
         assert_eq!(r.recv().await, Some(1));
@@ -808,7 +750,7 @@ mod tests {
 
     #[futures_test::test]
     async fn sender_send_completes_if_closed() {
-        static CHANNEL: Forever<Channel<WithCriticalSections, u32, 1>> = Forever::new();
+        static CHANNEL: Forever<Channel<CriticalSection, u32, 1>> = Forever::new();
         let c = CHANNEL.put(Channel::new());
         let (s, r) = split(c);
         drop(r);
@@ -822,7 +764,7 @@ mod tests {
     async fn senders_sends_wait_until_capacity() {
         let executor = ThreadPool::new().unwrap();
 
-        static CHANNEL: Forever<Channel<WithCriticalSections, u32, 1>> = Forever::new();
+        static CHANNEL: Forever<Channel<CriticalSection, u32, 1>> = Forever::new();
         let c = CHANNEL.put(Channel::new());
         let (s0, mut r) = split(c);
         assert!(s0.try_send(1).is_ok());
@@ -842,7 +784,7 @@ mod tests {
 
     #[futures_test::test]
     async fn sender_close_completes_if_closing() {
-        static CHANNEL: Forever<Channel<WithCriticalSections, u32, 1>> = Forever::new();
+        static CHANNEL: Forever<Channel<CriticalSection, u32, 1>> = Forever::new();
         let c = CHANNEL.put(Channel::new());
         let (s, mut r) = split(c);
         r.close();
@@ -851,7 +793,7 @@ mod tests {
 
     #[futures_test::test]
     async fn sender_close_completes_if_closed() {
-        static CHANNEL: Forever<Channel<WithCriticalSections, u32, 1>> = Forever::new();
+        static CHANNEL: Forever<Channel<CriticalSection, u32, 1>> = Forever::new();
         let c = CHANNEL.put(Channel::new());
         let (s, r) = split(c);
         drop(r);
diff --git a/examples/nrf/src/bin/mpsc.rs b/examples/nrf/src/bin/mpsc.rs
index 79fa3dfb9..c85b7c282 100644
--- a/examples/nrf/src/bin/mpsc.rs
+++ b/examples/nrf/src/bin/mpsc.rs
@@ -6,7 +6,8 @@
 mod example_common;
 
 use defmt::unwrap;
-use embassy::channel::mpsc::{self, Channel, Sender, TryRecvError, WithNoThreads};
+use embassy::blocking_mutex::kind::Noop;
+use embassy::channel::mpsc::{self, Channel, Sender, TryRecvError};
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy::util::Forever;
@@ -19,10 +20,10 @@ enum LedState {
     Off,
 }
 
-static CHANNEL: Forever<Channel<WithNoThreads, LedState, 1>> = Forever::new();
+static CHANNEL: Forever<Channel<Noop, LedState, 1>> = Forever::new();
 
 #[embassy::task(pool_size = 1)]
-async fn my_task(sender: Sender<'static, WithNoThreads, LedState, 1>) {
+async fn my_task(sender: Sender<'static, Noop, LedState, 1>) {
     loop {
         let _ = sender.send(LedState::On).await;
         Timer::after(Duration::from_secs(1)).await;