Implement RFC 11: Redesigning Wasmtime's APIs (#2897)

Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.

crates/wasi-common/tokio/src/file.rs

@@ -112,7 +112,7 @@ macro_rules! wasi_file_impl {
             }
 
             #[cfg(not(windows))]
-            async fn readable(&mut self) -> Result<(), Error> {
+            async fn readable(&self) -> Result<(), Error> {
                 // The Inner impls OwnsRaw, which asserts exclusive use of the handle by the owned object.
                 // AsyncFd needs to wrap an owned `impl std::os::unix::io::AsRawFd`. Rather than introduce
                 // mutability to let it own the `Inner`, we are depending on the `&mut self` bound on this
@@ -135,14 +135,14 @@ macro_rules! wasi_file_impl {
                 }
             }
             #[cfg(windows)]
-            async fn readable(&mut self) -> Result<(), Error> {
+            async fn readable(&self) -> Result<(), Error> {
                 // Windows uses a rawfd based scheduler :(
                 use wasi_common::ErrorExt;
                 Err(Error::badf())
             }
 
             #[cfg(not(windows))]
-            async fn writable(&mut self) -> Result<(), Error> {
+            async fn writable(&self) -> Result<(), Error> {
                 // The Inner impls OwnsRaw, which asserts exclusive use of the handle by the owned object.
                 // AsyncFd needs to wrap an owned `impl std::os::unix::io::AsRawFd`. Rather than introduce
                 // mutability to let it own the `Inner`, we are depending on the `&mut self` bound on this
@@ -165,7 +165,7 @@ macro_rules! wasi_file_impl {
                 }
             }
             #[cfg(windows)]
-            async fn writable(&mut self) -> Result<(), Error> {
+            async fn writable(&self) -> Result<(), Error> {
                 // Windows uses a rawfd based scheduler :(
                 use wasi_common::ErrorExt;
                 Err(Error::badf())

crates/wasi-common/tokio/src/lib.rs

@@ -3,10 +3,8 @@ mod file;
 pub mod sched;
 pub mod stdio;
 
-use std::cell::RefCell;
 use std::future::Future;
 use std::path::Path;
-use std::rc::Rc;
 pub use wasi_cap_std_sync::{clocks_ctx, random_ctx};
 use wasi_common::{Error, Table, WasiCtx, WasiFile};
 
@@ -23,7 +21,7 @@ impl WasiCtxBuilder {
             random_ctx(),
             clocks_ctx(),
             sched_ctx(),
-            Rc::new(RefCell::new(Table::new())),
+            Table::new(),
         ))
     }
     pub fn env(mut self, var: &str, value: &str) -> Result<Self, wasi_common::StringArrayError> {

crates/wasi-common/tokio/src/sched/unix.rs

@@ -9,13 +9,13 @@ use wasi_common::{
     Context as _, Error,
 };
 
-struct FirstReady<'a, T>(Vec<Pin<Box<dyn Future<Output = T> + 'a>>>);
+struct FirstReady<'a, T>(Vec<Pin<Box<dyn Future<Output = T> + Send + 'a>>>);
 
 impl<'a, T> FirstReady<'a, T> {
     fn new() -> Self {
         FirstReady(Vec::new())
     }
-    fn push(&mut self, f: impl Future<Output = T> + 'a) {
+    fn push(&mut self, f: impl Future<Output = T> + Send + 'a) {
         self.0.push(Box::pin(f));
     }
 }