feat(server-framework): add Server trait, Encode/Decode, async executor, syscall wrappers, and mock arch for host testing

crates/server-framework/src/executor/mod.rs

@@ -0,0 +1,35 @@
+#[cfg(test)]
+mod tests;
+
+use core::future::Future;
+use core::pin::Pin;
+use core::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
+
+fn noop_raw_waker() -> RawWaker {
+    fn no_op(_: *const ()) {}
+    fn clone(_: *const ()) -> RawWaker { noop_raw_waker() }
+    RawWaker::new(
+        core::ptr::null(),
+        &RawWakerVTable::new(clone, no_op, no_op, no_op),
+    )
+}
+
+fn noop_waker() -> Waker {
+    unsafe { Waker::from_raw(noop_raw_waker()) }
+}
+
+pub fn block_on<F: Future>(future: F) -> F::Output {
+    let waker = noop_waker();
+    let mut cx = Context::from_waker(&waker);
+    let mut future = core::pin::pin!(future);
+
+    loop {
+        match future.as_mut().poll(&mut cx) {
+            Poll::Ready(output) => return output,
+            Poll::Pending => {
+                #[cfg(not(test))]
+                userspace::syscall::yield_now();
+            }
+        }
+    }
+}

crates/server-framework/src/executor/tests.rs

@@ -0,0 +1,17 @@
+use super::*;
+
+#[test]
+fn block_on_ready_future() {
+    let result = block_on(async { 42 });
+    assert_eq!(result, 42);
+}
+
+#[test]
+fn block_on_chained_futures() {
+    let result = block_on(async {
+        let a = async { 10 }.await;
+        let b = async { 20 }.await;
+        a + b
+    });
+    assert_eq!(result, 30);
+}