library src

1 files changed, 74 insertions, 0 deletions

diff --git a/src/async_util.rs b/src/async_util.rs
new file mode 100644
index 00000000..bd8882d8
--- /dev/null
+++ b/src/async_util.rs
@@ -0,0 +1,74 @@
+//! Async support for RTIC
+
+use core::{
+    future::Future,
+    mem,
+    pin::Pin,
+    task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
+};
+
+//=============
+// Waker
+
+///
+pub static WAKER_VTABLE: RawWakerVTable =
+    RawWakerVTable::new(waker_clone, waker_wake, waker_wake, waker_drop);
+
+unsafe fn waker_clone(p: *const ()) -> RawWaker {
+    RawWaker::new(p, &WAKER_VTABLE)
+}
+
+unsafe fn waker_wake(p: *const ()) {
+    let f: fn() = mem::transmute(p);
+    f();
+}
+
+unsafe fn waker_drop(_: *const ()) {
+    // nop
+}
+
+//============
+// Task
+
+///
+pub enum Task<F: Future + 'static> {
+    ///
+    Idle,
+
+    ///
+    Running(F),
+
+    ///
+    Done(F::Output),
+}
+
+impl<F: Future + 'static> Task<F> {
+    ///
+    pub const fn new() -> Self {
+        Self::Idle
+    }
+
+    ///
+    pub fn spawn(&mut self, future: impl FnOnce() -> F) {
+        *self = Task::Running(future());
+    }
+
+    ///
+    pub unsafe fn poll(&mut self, wake: fn()) {
+        match self {
+            Task::Idle => {}
+            Task::Running(future) => {
+                let future = Pin::new_unchecked(future);
+                let waker_data: *const () = mem::transmute(wake);
+                let waker = Waker::from_raw(RawWaker::new(waker_data, &WAKER_VTABLE));
+                let mut cx = Context::from_waker(&waker);
+
+                match future.poll(&mut cx) {
+                    Poll::Ready(r) => *self = Task::Done(r),
+                    Poll::Pending => {}
+                };
+            }
+            Task::Done(_) => {}
+        }
+    }
+}