reuse cap-std-syncs windows scheduler without copypaste

crates/wasi-common/cap-std-sync/src/sched.rs

@@ -1,15 +1,40 @@
 #[cfg(unix)]
-mod unix;
+pub mod unix;
 #[cfg(unix)]
-pub use unix::*;
+pub use unix::poll_oneoff;
 
 #[cfg(windows)]
-mod windows;
+pub mod windows;
 #[cfg(windows)]
-pub use windows::*;
+pub use windows::poll_oneoff;
 
-use wasi_common::sched::WasiSched;
+use std::thread;
+use std::time::Duration;
+use wasi_common::{
+    sched::{Poll, WasiSched},
+    Error,
+};
 
+pub struct SyncSched {}
+impl SyncSched {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+#[async_trait::async_trait(?Send)]
+impl WasiSched for SyncSched {
+    async fn poll_oneoff<'a>(&self, poll: &mut Poll<'a>) -> Result<(), Error> {
+        poll_oneoff(poll).await
+    }
+    async fn sched_yield(&self) -> Result<(), Error> {
+        thread::yield_now();
+        Ok(())
+    }
+    async fn sleep(&self, duration: Duration) -> Result<(), Error> {
+        std::thread::sleep(duration);
+        Ok(())
+    }
+}
 pub fn sched_ctx() -> Box<dyn WasiSched> {
     Box::new(SyncSched::new())
 }