chore: deprecate async-io support in mDNS crate

Pull-Request: libp2p#5958.

Author: gitToki

Cargo.lock

@@ -86,7 +86,7 @@ libp2p-gossipsub = { version = "0.49.0", path = "protocols/gossipsub" }
 libp2p-identify = { version = "0.47.0", path = "protocols/identify" }
 libp2p-identity = { version = "0.2.11" }
 libp2p-kad = { version = "0.47.1", path = "protocols/kad" }
-libp2p-mdns = { version = "0.47.0", path = "protocols/mdns" }
+libp2p-mdns = { version = "0.48.0", path = "protocols/mdns" }
 libp2p-memory-connection-limits = { version = "0.4.0", path = "misc/memory-connection-limits" }
 libp2p-metrics = { version = "0.17.0", path = "misc/metrics" }
 libp2p-mplex = { version = "0.43.1", path = "muxers/mplex" }

Cargo.toml

@@ -53,7 +53,7 @@ full = [
     "upnp",
 ]
 
-async-std = [ "libp2p-swarm/async-std", "libp2p-mdns?/async-io", "libp2p-tcp?/async-io", "libp2p-dns?/async-std", "libp2p-quic?/async-std",]
+async-std = [ "libp2p-swarm/async-std", "libp2p-tcp?/async-io", "libp2p-dns?/async-std", "libp2p-quic?/async-std",]
 autonat = ["dep:libp2p-autonat"]
 cbor = ["libp2p-request-response?/cbor"]
 dcutr = ["dep:libp2p-dcutr", "libp2p-metrics?/dcutr"]

libp2p/Cargo.toml

@@ -1,3 +1,7 @@
+## 0.48.0
+
+- Remove `async_std` dependency [PR 5958](https://github.com/libp2p/rust-libp2p/pull/5958)
+
 ## 0.47.0
 
 - Emit `ToSwarm::NewExternalAddrOfPeer` on discovery.

protocols/mdns/CHANGELOG.md

@@ -2,7 +2,7 @@
 name = "libp2p-mdns"
 edition.workspace = true
 rust-version = { workspace = true }
-version = "0.47.0"
+version = "0.48.0"
 description = "Implementation of the libp2p mDNS discovery method"
 authors = ["Parity Technologies <[email protected]>"]
 license = "MIT"
@@ -11,8 +11,6 @@ keywords = ["peer-to-peer", "libp2p", "networking"]
 categories = ["network-programming", "asynchronous"]
 
 [dependencies]
-async-std  = { version = "1.12.0", optional = true }
-async-io  = { version = "2.3.3", optional = true }
 futures = { workspace = true }
 if-watch = { workspace = true }
 libp2p-core = { workspace = true }
@@ -21,25 +19,19 @@ libp2p-identity = { workspace = true }
 rand = "0.8.3"
 smallvec = "1.13.2"
 socket2 = { version = "0.5.7", features = ["all"] }
-tokio = { workspace = true, default-features = false, features = ["net", "time"], optional = true}
+tokio = { workspace = true, default-features = false, features = ["net", "time"], optional = true }
 tracing = { workspace = true }
 hickory-proto = { workspace = true, features = ["mdns"] }
 
 [features]
 tokio = ["dep:tokio", "if-watch/tokio"]
-async-io = ["dep:async-io", "dep:async-std", "if-watch/smol"]
 
 [dev-dependencies]
-async-std = { version = "1.9.0", features = ["attributes"] }
-libp2p-swarm = { workspace = true, features = ["tokio", "async-std"] }
+libp2p-swarm = { workspace = true, features = ["tokio"] }
 tokio = { workspace = true, features = ["macros", "rt", "rt-multi-thread", "time"] }
 libp2p-swarm-test = { path = "../../swarm-test" }
 tracing-subscriber = { workspace = true, features = ["env-filter"] }
 
-[[test]]
-name = "use-async-std"
-required-features = ["async-io", "libp2p-swarm-test/async-std"]
-
 [[test]]
 name = "use-tokio"
 required-features = ["tokio", "libp2p-swarm-test/tokio"]

protocols/mdns/Cargo.toml

@@ -78,44 +78,6 @@ pub trait Abort {
     fn abort(self);
 }
 
-/// The type of a [`Behaviour`] using the `async-io` implementation.
-#[cfg(feature = "async-io")]
-pub mod async_io {
-    use std::future::Future;
-
-    use async_std::task::JoinHandle;
-    use if_watch::smol::IfWatcher;
-
-    use super::Provider;
-    use crate::behaviour::{socket::asio::AsyncUdpSocket, timer::asio::AsyncTimer, Abort};
-
-    #[doc(hidden)]
-    pub enum AsyncIo {}
-
-    impl Provider for AsyncIo {
-        type Socket = AsyncUdpSocket;
-        type Timer = AsyncTimer;
-        type Watcher = IfWatcher;
-        type TaskHandle = JoinHandle<()>;
-
-        fn new_watcher() -> Result<Self::Watcher, std::io::Error> {
-            IfWatcher::new()
-        }
-
-        fn spawn(task: impl Future<Output = ()> + Send + 'static) -> JoinHandle<()> {
-            async_std::task::spawn(task)
-        }
-    }
-
-    impl Abort for JoinHandle<()> {
-        fn abort(self) {
-            async_std::task::spawn(self.cancel());
-        }
-    }
-
-    pub type Behaviour = super::Behaviour<AsyncIo>;
-}
-
 /// The type of a [`Behaviour`] using the `tokio` implementation.
 #[cfg(feature = "tokio")]
 pub mod tokio {

protocols/mdns/src/behaviour.rs

@@ -50,49 +50,6 @@ pub trait AsyncSocket: Unpin + Send + 'static {
     ) -> Poll<Result<(), Error>>;
 }
 
-#[cfg(feature = "async-io")]
-pub(crate) mod asio {
-    use async_io::Async;
-    use futures::FutureExt;
-
-    use super::*;
-
-    /// AsyncIo UdpSocket
-    pub(crate) type AsyncUdpSocket = Async<UdpSocket>;
-    impl AsyncSocket for AsyncUdpSocket {
-        fn from_std(socket: UdpSocket) -> std::io::Result<Self> {
-            Async::new(socket)
-        }
-
-        fn poll_read(
-            &mut self,
-            cx: &mut Context,
-            buf: &mut [u8],
-        ) -> Poll<Result<(usize, SocketAddr), Error>> {
-            // Poll receive socket.
-            futures::ready!(self.poll_readable(cx))?;
-            match self.recv_from(buf).now_or_never() {
-                Some(data) => Poll::Ready(data),
-                None => Poll::Pending,
-            }
-        }
-
-        fn poll_write(
-            &mut self,
-            cx: &mut Context,
-            packet: &[u8],
-            to: SocketAddr,
-        ) -> Poll<Result<(), Error>> {
-            futures::ready!(self.poll_writable(cx))?;
-            match self.send_to(packet, to).now_or_never() {
-                Some(Ok(_)) => Poll::Ready(Ok(())),
-                Some(Err(err)) => Poll::Ready(Err(err)),
-                None => Poll::Pending,
-            }
-        }
-    }
-}
-
 #[cfg(feature = "tokio")]
 pub(crate) mod tokio {
     use ::tokio::{io::ReadBuf, net::UdpSocket as TkUdpSocket};

protocols/mdns/src/behaviour/socket.rs

@@ -22,7 +22,7 @@ use std::time::{Duration, Instant};
 
 /// Simple wrapper for the different type of timers
 #[derive(Debug)]
-#[cfg(any(feature = "async-io", feature = "tokio"))]
+#[cfg(feature = "tokio")]
 pub struct Timer<T> {
     inner: T,
 }
@@ -40,49 +40,6 @@ pub trait Builder: Send + Unpin + 'static {
     fn interval_at(start: Instant, duration: Duration) -> Self;
 }
 
-#[cfg(feature = "async-io")]
-pub(crate) mod asio {
-    use std::{
-        pin::Pin,
-        task::{Context, Poll},
-    };
-
-    use async_io::Timer as AsioTimer;
-    use futures::Stream;
-
-    use super::*;
-
-    /// Async Timer
-    pub(crate) type AsyncTimer = Timer<AsioTimer>;
-    impl Builder for AsyncTimer {
-        fn at(instant: Instant) -> Self {
-            Self {
-                inner: AsioTimer::at(instant),
-            }
-        }
-
-        fn interval(duration: Duration) -> Self {
-            Self {
-                inner: AsioTimer::interval(duration),
-            }
-        }
-
-        fn interval_at(start: Instant, duration: Duration) -> Self {
-            Self {
-                inner: AsioTimer::interval_at(start, duration),
-            }
-        }
-    }
-
-    impl Stream for AsyncTimer {
-        type Item = Instant;
-
-        fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-            Pin::new(&mut self.inner).poll_next(cx)
-        }
-    }
-}
-
 #[cfg(feature = "tokio")]
 pub(crate) mod tokio {
     use std::{

protocols/mdns/src/behaviour/timer.rs

@@ -28,8 +28,8 @@
 //!
 //! # Usage
 //!
-//! This crate provides a `Mdns` and `TokioMdns`, depending on the enabled features, which
-//! implements the `NetworkBehaviour` trait. This struct will automatically discover other
+//! This crate provides `TokioMdns`
+//! which implements the `NetworkBehaviour` trait. This struct will automatically discover other
 //! libp2p nodes on the local network.
 
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
@@ -40,8 +40,6 @@ use std::{
 };
 
 mod behaviour;
-#[cfg(feature = "async-io")]
-pub use crate::behaviour::async_io;
 #[cfg(feature = "tokio")]
 pub use crate::behaviour::tokio;
 pub use crate::behaviour::{Behaviour, Event};