feat: support for target wasm32-wasi

Signed-off-by: Richard Zak <richard@profian.com>
Co-authored-by: Harald Hoyer <harald@profian.com>

tokio-util/src/lib.rs

@@ -29,6 +29,7 @@ cfg_codec! {
 }
 
 cfg_net! {
+    #[cfg(not(target_arch = "wasm32"))]
     pub mod udp;
     pub mod net;
 }

tokio-util/src/net/mod.rs

@@ -39,9 +39,16 @@ impl Listener for tokio::net::TcpListener {
         Self::poll_accept(self, cx)
     }
 
+    #[cfg(not(target_os = "wasi"))]
     fn local_addr(&self) -> Result<Self::Addr> {
         self.local_addr().map(Into::into)
     }
+
+    #[cfg(target_os = "wasi")]
+    fn local_addr(&self) -> Result<Self::Addr> {
+        use std::io;
+        Err(io::ErrorKind::Unsupported.into())
+    }
 }
 
 /// Future for accepting a new connection from a listener.

tokio/Cargo.toml

@@ -51,7 +51,6 @@ net = [
   "mio/os-poll",
   "mio/os-ext",
   "mio/net",
-  "socket2",
   "winapi/namedpipeapi",
 ]
 process = [
@@ -97,11 +96,14 @@ pin-project-lite = "0.2.0"
 bytes = { version = "1.0.0", optional = true }
 once_cell = { version = "1.5.2", optional = true }
 memchr = { version = "2.2", optional = true }
-mio = { version = "0.8.1", optional = true }
-socket2 = { version = "0.4.4", optional = true, features = [ "all" ] }
+#mio = { version = "0.8.1", optional = true }
+mio = { git = "https://github.com/tokio-rs/mio/", branch = "master", optional = true }
 num_cpus = { version = "1.8.0", optional = true }
 parking_lot = { version = "0.12.0", optional = true }
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+socket2 = { version = "0.4.4", features = [ "all" ] }
+
 # Currently unstable. The API exposed by these features may be broken at any time.
 # Requires `--cfg tokio_unstable` to enable.
 [target.'cfg(tokio_unstable)'.dependencies]

tokio/src/io/driver/mod.rs

@@ -72,6 +72,7 @@ pub(super) struct Inner {
     io_dispatch: RwLock<IoDispatcher>,
 
     /// Used to wake up the reactor from a call to `turn`.
+    #[cfg(not(target_os = "wasi"))]
     waker: mio::Waker,
 
     metrics: IoDriverMetrics,
@@ -115,6 +116,7 @@ impl Driver {
     /// creation.
     pub(crate) fn new() -> io::Result<Driver> {
         let poll = mio::Poll::new()?;
+        #[cfg(not(target_os = "wasi"))]
         let waker = mio::Waker::new(poll.registry(), TOKEN_WAKEUP)?;
         let registry = poll.registry().try_clone()?;
 
@@ -129,6 +131,7 @@ impl Driver {
             inner: Arc::new(Inner {
                 registry,
                 io_dispatch: RwLock::new(IoDispatcher::new(allocator)),
+                #[cfg(not(target_os = "wasi"))]
                 waker,
                 metrics: IoDriverMetrics::default(),
             }),
@@ -299,6 +302,7 @@ impl Handle {
     /// blocked in `turn`, then the next call to `turn` will not block and
     /// return immediately.
     fn wakeup(&self) {
+        #[cfg(not(target_os = "wasi"))]
         self.inner.waker.wake().expect("failed to wake I/O driver");
     }
 }

tokio/src/io/poll_evented.rs

@@ -126,6 +126,7 @@ impl<E: Source> PollEvented<E> {
 
     /// Deregisters the inner io from the registration and returns a Result containing the inner io.
     #[cfg(any(feature = "net", feature = "process"))]
+    #[cfg(not(target_os = "wasi"))]
     pub(crate) fn into_inner(mut self) -> io::Result<E> {
         let mut inner = self.io.take().unwrap(); // As io shouldn't ever be None, just unwrap here.
         self.registration.deregister(&mut inner)?;

tokio/src/lib.rs

@@ -410,7 +410,9 @@ mod future;
 pub mod io;
 pub mod net;
 
+#[cfg(not(target_arch = "wasm32-wasi"))]
 mod loom;
+#[cfg(not(target_arch = "wasm32-wasi"))]
 mod park;
 
 cfg_process! {

tokio/src/macros/cfg.rs

@@ -61,6 +61,7 @@ macro_rules! cfg_fs {
     ($($item:item)*) => {
         $(
             #[cfg(feature = "fs")]
+            #[cfg(not(target_arch = "wasm32"))]
             #[cfg_attr(docsrs, doc(cfg(feature = "fs")))]
             $item
         )*
@@ -154,13 +155,21 @@ macro_rules! cfg_not_io_util {
 
 macro_rules! cfg_loom {
     ($($item:item)*) => {
-        $( #[cfg(loom)] $item )*
+        $(
+            #[cfg(loom)]
+            #[cfg(not(target_os = "wasi"))]
+            $item
+        )*
     }
 }
 
 macro_rules! cfg_not_loom {
     ($($item:item)*) => {
-        $( #[cfg(not(loom))] $item )*
+        $(
+            #[cfg(any(not(loom), target_os = "wasi"))]
+            //#[cfg(target_os = "wasi")]
+            $item
+        )*
     }
 }
 
@@ -247,6 +256,7 @@ macro_rules! cfg_process {
             #[cfg(feature = "process")]
             #[cfg_attr(docsrs, doc(cfg(feature = "process")))]
             #[cfg(not(loom))]
+            #[cfg(not(target_arch = "wasm32"))]
             $item
         )*
     }
@@ -275,6 +285,7 @@ macro_rules! cfg_signal {
             #[cfg(feature = "signal")]
             #[cfg_attr(docsrs, doc(cfg(feature = "signal")))]
             #[cfg(not(loom))]
+            #[cfg(not(target_arch = "wasm32"))]
             $item
         )*
     }
@@ -451,7 +462,8 @@ macro_rules! cfg_has_atomic_u64 {
                     target_arch = "arm",
                     target_arch = "mips",
                     target_arch = "powerpc",
-                    target_arch = "riscv32"
+                    target_arch = "riscv32",
+                    target_arch = "wasm32"
                     )))]
             $item
         )*
@@ -465,7 +477,8 @@ macro_rules! cfg_not_has_atomic_u64 {
                     target_arch = "arm",
                     target_arch = "mips",
                     target_arch = "powerpc",
-                    target_arch = "riscv32"
+                    target_arch = "riscv32",
+                    target_arch = "wasm32"
                     ))]
             $item
         )*

tokio/src/net/mod.rs

@@ -23,7 +23,7 @@
 //! [`UnixDatagram`]: UnixDatagram
 
 mod addr;
-#[cfg(feature = "net")]
+#[cfg(all(feature = "net", not(target_os = "wasi")))]
 pub(crate) use addr::to_socket_addrs;
 pub use addr::ToSocketAddrs;
 
@@ -33,10 +33,13 @@ cfg_net! {
 
     pub mod tcp;
     pub use tcp::listener::TcpListener;
+    #[cfg(not(target_os = "wasi"))]
     pub use tcp::socket::TcpSocket;
     pub use tcp::stream::TcpStream;
 
+    #[cfg(not(target_os = "wasi"))]
     mod udp;
+    #[cfg(not(target_os = "wasi"))]
     pub use udp::UdpSocket;
 }
 

tokio/src/net/tcp/listener.rs

@@ -1,5 +1,7 @@
 use crate::io::{Interest, PollEvented};
 use crate::net::tcp::TcpStream;
+
+#[cfg(not(target_os = "wasi"))]
 use crate::net::{to_socket_addrs, ToSocketAddrs};
 
 use std::convert::TryFrom;
@@ -94,6 +96,7 @@ impl TcpListener {
     ///     Ok(())
     /// }
     /// ```
+    #[cfg(not(target_os = "wasi"))]
     pub async fn bind<A: ToSocketAddrs>(addr: A) -> io::Result<TcpListener> {
         let addrs = to_socket_addrs(addr).await?;
 
@@ -114,6 +117,7 @@ impl TcpListener {
         }))
     }
 
+    #[cfg(not(target_os = "wasi"))]
     fn bind_addr(addr: SocketAddr) -> io::Result<TcpListener> {
         let listener = mio::net::TcpListener::bind(addr)?;
         TcpListener::new(listener)
@@ -249,6 +253,7 @@ impl TcpListener {
     /// [`tokio::net::TcpListener`]: TcpListener
     /// [`std::net::TcpListener`]: std::net::TcpListener
     /// [`set_nonblocking`]: fn@std::net::TcpListener::set_nonblocking
+    #[cfg(not(target_os = "wasi"))]
     pub fn into_std(self) -> io::Result<std::net::TcpListener> {
         #[cfg(unix)]
         {
@@ -269,6 +274,7 @@ impl TcpListener {
         }
     }
 
+    #[cfg(not(target_os = "wasi"))]
     pub(crate) fn new(listener: mio::net::TcpListener) -> io::Result<TcpListener> {
         let io = PollEvented::new(listener)?;
         Ok(TcpListener { io })
@@ -297,6 +303,7 @@ impl TcpListener {
     ///     Ok(())
     /// }
     /// ```
+    #[cfg(not(target_os = "wasi"))]
     pub fn local_addr(&self) -> io::Result<SocketAddr> {
         self.io.local_addr()
     }
@@ -384,6 +391,18 @@ mod sys {
     }
 }
 
+#[cfg(target_os = "wasi")]
+mod sys {
+    use super::TcpListener;
+    use std::os::wasi::prelude::*;
+
+    impl AsRawFd for TcpListener {
+        fn as_raw_fd(&self) -> RawFd {
+            self.io.as_raw_fd()
+        }
+    }
+}
+
 #[cfg(windows)]
 mod sys {
     use super::TcpListener;

tokio/src/net/tcp/socket.rs

@@ -1,3 +1,4 @@
+#![cfg(not(target_os = "wasi"))]
 use crate::net::{TcpListener, TcpStream};
 
 use std::fmt;

tokio/src/net/tcp/stream.rs

@@ -1,7 +1,11 @@
+#[cfg(not(target_os = "wasi"))]
 use crate::future::poll_fn;
+
 use crate::io::{AsyncRead, AsyncWrite, Interest, PollEvented, ReadBuf, Ready};
 use crate::net::tcp::split::{split, ReadHalf, WriteHalf};
 use crate::net::tcp::split_owned::{split_owned, OwnedReadHalf, OwnedWriteHalf};
+
+#[cfg(not(target_os = "wasi"))]
 use crate::net::{to_socket_addrs, ToSocketAddrs};
 
 use std::convert::TryFrom;
@@ -108,6 +112,7 @@ impl TcpStream {
     ///
     /// [`write_all`]: fn@crate::io::AsyncWriteExt::write_all
     /// [`AsyncWriteExt`]: trait@crate::io::AsyncWriteExt
+    #[cfg(not(target_os = "wasi"))]
     pub async fn connect<A: ToSocketAddrs>(addr: A) -> io::Result<TcpStream> {
         let addrs = to_socket_addrs(addr).await?;
 
@@ -129,11 +134,13 @@ impl TcpStream {
     }
 
     /// Establishes a connection to the specified `addr`.
+    #[cfg(not(target_os = "wasi"))]
     async fn connect_addr(addr: SocketAddr) -> io::Result<TcpStream> {
         let sys = mio::net::TcpStream::connect(addr)?;
         TcpStream::connect_mio(sys).await
     }
 
+    #[cfg(not(target_os = "wasi"))]
     pub(crate) async fn connect_mio(sys: mio::net::TcpStream) -> io::Result<TcpStream> {
         let stream = TcpStream::new(sys)?;
 
@@ -226,6 +233,7 @@ impl TcpStream {
     /// [`tokio::net::TcpStream`]: TcpStream
     /// [`std::net::TcpStream`]: std::net::TcpStream
     /// [`set_nonblocking`]: fn@std::net::TcpStream::set_nonblocking
+    #[cfg(not(target_os = "wasi"))]
     pub fn into_std(self) -> io::Result<std::net::TcpStream> {
         #[cfg(unix)]
         {
@@ -1096,10 +1104,17 @@ impl TcpStream {
     /// # Ok(())
     /// # }
     /// ```
+    #[cfg(not(target_os = "wasi"))]
     pub fn linger(&self) -> io::Result<Option<Duration>> {
         socket2::SockRef::from(self).linger()
     }
 
+    /// Returns `io::ErrorKind::Unsupported` as this is not supported on WebAssembly
+    #[cfg(target_os = "wasi")]
+    pub fn linger(&self) -> io::Result<Option<Duration>> {
+        Err(io::ErrorKind::Unsupported.into())
+    }
+
     /// Sets the linger duration of this socket by setting the SO_LINGER option.
     ///
     /// This option controls the action taken when a stream has unsent messages and the stream is
@@ -1121,10 +1136,18 @@ impl TcpStream {
     /// # Ok(())
     /// # }
     /// ```
+    #[cfg(not(target_os = "wasi"))]
     pub fn set_linger(&self, dur: Option<Duration>) -> io::Result<()> {
         socket2::SockRef::from(self).set_linger(dur)
     }
 
+    /// Returns `io::ErrorKind::Unsupported` as this is not supported on WebAssembly
+    #[cfg(target_os = "wasi")]
+    #[allow(unused_variables)]
+    pub fn set_linger(&self, dur: Option<Duration>) -> io::Result<()> {
+        Err(io::ErrorKind::Unsupported.into())
+    }
+
     /// Gets the value of the `IP_TTL` option for this socket.
     ///
     /// For more information about this option, see [`set_ttl`].