need Any on WasiFile to upcast for AsRawFd

crates/wasi-c2/src/file.rs

@@ -1,11 +1,13 @@
 use crate::Error;
 use bitflags::bitflags;
 use fs_set_times::SetTimes;
+use std::any::Any;
 use std::cell::Ref;
 use std::ops::Deref;
 use system_interface::fs::FileIoExt;
 
 pub trait WasiFile: FileIoExt + SetTimes {
+    fn as_any(&self) -> &dyn Any;
     fn datasync(&self) -> Result<(), Error>;
     fn sync(&self) -> Result<(), Error>;
     fn get_filetype(&self) -> Result<FileType, Error>;
@@ -165,6 +167,9 @@ pub struct FdStat {
 }
 
 impl WasiFile for cap_std::fs::File {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
     fn datasync(&self) -> Result<(), Error> {
         self.sync_data()?;
         Ok(())

crates/wasi-c2/src/sched.rs

@@ -5,32 +5,23 @@ use cap_std::time::{Duration, SystemTime};
 use std::cell::Ref;
 pub mod subscription;
 
+mod sync;
+pub use sync::SyncSched;
+
 use subscription::{RwSubscription, Subscription, SubscriptionResult, SystemTimerSubscription};
 
 pub trait WasiSched {
-    fn poll_oneoff<'a>(&self, poll: &mut Poll<'a>) -> Result<(), Error>;
+    fn poll_oneoff(&self, poll: &Poll) -> Result<(), Error>;
     fn sched_yield(&self) -> Result<(), Error>;
 }
 
-#[derive(Default)]
-pub struct SyncSched {}
-
-impl WasiSched for SyncSched {
-    fn poll_oneoff<'a>(&self, poll: &mut Poll<'a>) -> Result<(), Error> {
-        todo!()
-    }
-    fn sched_yield(&self) -> Result<(), Error> {
-        std::thread::yield_now();
-        Ok(())
-    }
-}
-
 pub struct Userdata(u64);
 impl From<u64> for Userdata {
     fn from(u: u64) -> Userdata {
         Userdata(u)
     }
 }
+
 impl From<Userdata> for u64 {
     fn from(u: Userdata) -> u64 {
         u.0
@@ -75,7 +66,7 @@ impl<'a> Poll<'a> {
             .filter_map(|(s, ud)| SubscriptionResult::from_subscription(s).map(|r| (r, ud)))
             .collect()
     }
-    pub fn subscriptions(&'a mut self) -> impl Iterator<Item = &Subscription<'a>> {
+    pub fn subscriptions(&'a self) -> impl Iterator<Item = &Subscription<'a>> {
         self.subs.iter().map(|(s, _ud)| s)
     }
 }

crates/wasi-c2/src/sched/subscription.rs

@@ -12,7 +12,7 @@ bitflags! {
 }
 
 pub struct RwSubscription<'a> {
-    file: Ref<'a, dyn WasiFile>,
+    pub file: Ref<'a, dyn WasiFile>,
     status: Cell<Option<Result<(u64, RwEventFlags), Error>>>,
 }
 

crates/wasi-c2/src/sched/sync.rs

@@ -0,0 +1,55 @@
+use crate::file::WasiFile;
+use crate::sched::subscription::{RwSubscription, Subscription, SystemTimerSubscription};
+use crate::sched::{Poll, WasiSched};
+use crate::Error;
+use std::any::Any;
+use std::ops::Deref;
+#[cfg(unix)]
+use std::os::unix::io::{AsRawFd, RawFd};
+
+#[derive(Default)]
+pub struct SyncSched {}
+
+impl WasiSched for SyncSched {
+    fn poll_oneoff(&self, poll: &Poll) -> Result<(), Error> {
+        for s in poll.subscriptions() {
+            match s {
+                Subscription::Read(f) | Subscription::Write(f) => {
+                    let raw_fd = wasi_file_raw_fd(f.file.deref()).ok_or(Error::Inval)?;
+                    todo!()
+                }
+                Subscription::SystemTimer(t) => {
+                    todo!()
+                }
+            }
+        }
+        Ok(())
+    }
+    fn sched_yield(&self) -> Result<(), Error> {
+        std::thread::yield_now();
+        Ok(())
+    }
+}
+
+fn wasi_file_raw_fd(f: &dyn WasiFile) -> Option<RawFd> {
+    let a = f.as_any();
+    if a.is::<cap_std::fs::File>() {
+        Some(a.downcast_ref::<cap_std::fs::File>().unwrap().as_raw_fd())
+    } else if a.is::<crate::stdio::Stdin>() {
+        Some(a.downcast_ref::<crate::stdio::Stdin>().unwrap().as_raw_fd())
+    } else if a.is::<crate::stdio::Stdout>() {
+        Some(
+            a.downcast_ref::<crate::stdio::Stdout>()
+                .unwrap()
+                .as_raw_fd(),
+        )
+    } else if a.is::<crate::stdio::Stderr>() {
+        Some(
+            a.downcast_ref::<crate::stdio::Stderr>()
+                .unwrap()
+                .as_raw_fd(),
+        )
+    } else {
+        None
+    }
+}

crates/wasi-c2/src/snapshots/preview_1.rs

@@ -939,7 +939,7 @@ impl<'a> wasi_snapshot_preview1::WasiSnapshotPreview1 for WasiCtx {
             }
         }
 
-        self.sched.poll_oneoff(&mut poll)?;
+        self.sched.poll_oneoff(&poll)?;
 
         let results = poll.results();
         let num_results = results.len();

crates/wasi-c2/src/stdio.rs

@@ -1,5 +1,6 @@
 use crate::file::{FdFlags, FileType, Filestat, WasiFile};
 use crate::Error;
+use std::any::Any;
 #[cfg(unix)]
 use std::os::unix::io::{AsRawFd, RawFd};
 
@@ -17,6 +18,9 @@ impl AsRawFd for Stdin {
 }
 
 impl WasiFile for Stdin {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
     fn datasync(&self) -> Result<(), Error> {
         Ok(())
     }
@@ -54,6 +58,9 @@ impl AsRawFd for Stdout {
 }
 
 impl WasiFile for Stdout {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
     fn datasync(&self) -> Result<(), Error> {
         Ok(())
     }
@@ -91,6 +98,9 @@ impl AsRawFd for Stderr {
 }
 
 impl WasiFile for Stderr {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
     fn datasync(&self) -> Result<(), Error> {
         Ok(())
     }

crates/wasi-c2/src/virt/pipe.rs

@@ -11,6 +11,7 @@
 //!
 use crate::file::{FdFlags, FileType, Filestat, WasiFile};
 use crate::Error;
+use std::any::Any;
 use std::io::{self, Read, Write};
 use std::sync::{Arc, RwLock};
 use system_interface::fs::{Advice, FileIoExt};
@@ -167,7 +168,10 @@ impl<R: Read> fs_set_times::SetTimes for ReadPipe<R> {
         todo!()
     }
 }
-impl<R: Read> WasiFile for ReadPipe<R> {
+impl<R: Read + Any> WasiFile for ReadPipe<R> {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
     fn datasync(&self) -> Result<(), Error> {
         Ok(()) // trivial: no implementation needed
     }
@@ -339,7 +343,10 @@ impl<W: Write> fs_set_times::SetTimes for WritePipe<W> {
     }
 }
 
-impl<W: Write> WasiFile for WritePipe<W> {
+impl<W: Write + Any> WasiFile for WritePipe<W> {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
     fn datasync(&self) -> Result<(), Error> {
         Ok(())
     }