tor_rtcompat/impls/
async_std.rs

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1//! Re-exports of the async_std runtime for use with arti.
2//!
3//! This crate helps define a slim API around our async runtime so that we
4//! can easily swap it out.
5//!
6//! We'll probably want to support tokio as well in the future.
7
8/// Types used for networking (async_std implementation)
9mod net {
10    use crate::{impls, traits};
11
12    use async_std_crate::net::{TcpListener, TcpStream, UdpSocket as StdUdpSocket};
13    #[cfg(unix)]
14    use async_std_crate::os::unix::net::{UnixListener, UnixStream};
15    use async_trait::async_trait;
16    use futures::future::Future;
17    use futures::stream::Stream;
18    use paste::paste;
19    use std::io::Result as IoResult;
20    use std::net::SocketAddr;
21    use std::pin::Pin;
22    use std::task::{Context, Poll};
23    use tor_general_addr::unix;
24
25    /// Implement NetStreamProvider-related functionality for a single address type.
26    macro_rules! impl_stream {
27        { $kind:ident, $addr:ty } => {paste!{
28            /// A `Stream` of incoming streams.
29            ///
30            /// Differs from the output of `*Listener::incoming` in that this
31            /// struct is a real type, and that it returns a stream and an address
32            /// for each input.
33            pub struct [<Incoming $kind Streams>] {
34                /// A state object, stored in an Option so we can take ownership of it
35                /// while poll is being called.
36                // TODO(nickm): I hate using this trick.  At some point in the
37                // future, once Rust has nice support for async traits, maybe
38                // we can refactor it.
39                state: Option<[<Incoming $kind StreamsState>]>,
40            }
41            /// The result type returned by `take_and_poll_*`.
42            ///
43            /// It has to include the Listener, since take_and_poll() has
44            /// ownership of the listener.
45            type [<$kind FResult>] = (IoResult<([<$kind Stream>], $addr)>, [<$kind Listener>]);
46            /// Helper to implement `Incoming*Streams`
47            ///
48            /// This function calls `Listener::accept` while owning the
49            /// listener.  Thus, it returns a future that itself owns the listener,
50            /// and we don't have lifetime troubles.
51            async fn [<take_and_poll_ $kind:lower>](lis: [<$kind Listener>]) -> [<$kind FResult>] {
52                let result = lis.accept().await;
53                (result, lis)
54            }
55            /// The possible states for an `Incoming*Streams`.
56            enum [<Incoming $kind StreamsState>] {
57                /// We're ready to call `accept` on the listener again.
58                Ready([<$kind Listener>]),
59                /// We've called `accept` on the listener, and we're waiting
60                /// for a future to complete.
61                Accepting(Pin<Box<dyn Future<Output = [<$kind FResult>]> + Send + Sync>>),
62            }
63            impl [<Incoming $kind Streams>] {
64                /// Create a new IncomingStreams from a Listener.
65                pub fn from_listener(lis: [<$kind Listener>]) -> [<Incoming $kind Streams>] {
66                    Self {
67                        state: Some([<Incoming $kind StreamsState>]::Ready(lis)),
68                    }
69                }
70            }
71            impl Stream for [< Incoming $kind Streams >] {
72                type Item = IoResult<([<$kind Stream>], $addr)>;
73
74                fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
75                    use [<Incoming $kind StreamsState>] as St;
76                    let state = self.state.take().expect("No valid state!");
77                    let mut future = match state {
78                        St::Ready(lis) => Box::pin([<take_and_poll_ $kind:lower>](lis)),
79                        St::Accepting(fut) => fut,
80                    };
81                    match future.as_mut().poll(cx) {
82                        Poll::Ready((val, lis)) => {
83                            self.state = Some(St::Ready(lis));
84                            Poll::Ready(Some(val))
85                        }
86                        Poll::Pending => {
87                            self.state = Some(St::Accepting(future));
88                            Poll::Pending
89                        }
90                    }
91                }
92            }
93            impl traits::NetStreamListener<$addr> for [<$kind Listener>] {
94                type Stream = [<$kind Stream>];
95                type Incoming = [<Incoming $kind Streams>];
96                fn incoming(self) -> [<Incoming $kind Streams>] {
97                    [<Incoming $kind Streams>]::from_listener(self)
98                }
99                fn local_addr(&self) -> IoResult<$addr> {
100                    [<$kind Listener>]::local_addr(self)
101                }
102            }
103        }}
104    }
105
106    impl_stream! { Tcp, std::net::SocketAddr }
107    #[cfg(unix)]
108    impl_stream! { Unix, unix::SocketAddr}
109
110    #[async_trait]
111    impl traits::NetStreamProvider<std::net::SocketAddr> for async_executors::AsyncStd {
112        type Stream = TcpStream;
113        type Listener = TcpListener;
114        async fn connect(&self, addr: &SocketAddr) -> IoResult<Self::Stream> {
115            TcpStream::connect(addr).await
116        }
117        async fn listen(&self, addr: &SocketAddr) -> IoResult<Self::Listener> {
118            TcpListener::bind(*addr).await
119        }
120    }
121
122    #[cfg(unix)]
123    #[async_trait]
124    impl traits::NetStreamProvider<unix::SocketAddr> for async_executors::AsyncStd {
125        type Stream = UnixStream;
126        type Listener = UnixListener;
127        async fn connect(&self, addr: &unix::SocketAddr) -> IoResult<Self::Stream> {
128            let path = addr
129                .as_pathname()
130                .ok_or(crate::unix::UnsupportedAfUnixAddressType)?;
131            UnixStream::connect(path).await
132        }
133        async fn listen(&self, addr: &unix::SocketAddr) -> IoResult<Self::Listener> {
134            let path = addr
135                .as_pathname()
136                .ok_or(crate::unix::UnsupportedAfUnixAddressType)?;
137            UnixListener::bind(path).await
138        }
139    }
140
141    #[cfg(not(unix))]
142    crate::impls::impl_unix_non_provider! { async_executors::AsyncStd }
143
144    #[async_trait]
145    impl traits::UdpProvider for async_executors::AsyncStd {
146        type UdpSocket = UdpSocket;
147
148        async fn bind(&self, addr: &std::net::SocketAddr) -> IoResult<Self::UdpSocket> {
149            StdUdpSocket::bind(*addr)
150                .await
151                .map(|socket| UdpSocket { socket })
152        }
153    }
154
155    /// Wrap a AsyncStd UdpSocket
156    pub struct UdpSocket {
157        /// The underlying UdpSocket
158        socket: StdUdpSocket,
159    }
160
161    #[async_trait]
162    impl traits::UdpSocket for UdpSocket {
163        async fn recv(&self, buf: &mut [u8]) -> IoResult<(usize, SocketAddr)> {
164            self.socket.recv_from(buf).await
165        }
166
167        async fn send(&self, buf: &[u8], target: &SocketAddr) -> IoResult<usize> {
168            self.socket.send_to(buf, target).await
169        }
170
171        fn local_addr(&self) -> IoResult<SocketAddr> {
172            self.socket.local_addr()
173        }
174    }
175
176    impl traits::StreamOps for TcpStream {
177        fn set_tcp_notsent_lowat(&self, notsent_lowat: u32) -> IoResult<()> {
178            impls::streamops::set_tcp_notsent_lowat(self, notsent_lowat)
179        }
180
181        #[cfg(target_os = "linux")]
182        fn new_handle(&self) -> Box<dyn traits::StreamOps + Send + Unpin> {
183            Box::new(impls::streamops::TcpSockFd::from_fd(self))
184        }
185    }
186
187    #[cfg(unix)]
188    impl traits::StreamOps for UnixStream {
189        fn set_tcp_notsent_lowat(&self, _notsent_lowat: u32) -> IoResult<()> {
190            Err(traits::UnsupportedStreamOp::new(
191                "set_tcp_notsent_lowat",
192                "unsupported on Unix streams",
193            )
194            .into())
195        }
196    }
197}
198
199// ==============================
200
201use futures::{Future, FutureExt};
202use std::pin::Pin;
203use std::time::Duration;
204
205use crate::traits::*;
206
207/// Create and return a new `async_std` runtime.
208pub fn create_runtime() -> async_executors::AsyncStd {
209    async_executors::AsyncStd::new()
210}
211
212impl SleepProvider for async_executors::AsyncStd {
213    type SleepFuture = Pin<Box<dyn Future<Output = ()> + Send + 'static>>;
214    fn sleep(&self, duration: Duration) -> Self::SleepFuture {
215        Box::pin(async_io::Timer::after(duration).map(|_| ()))
216    }
217}
218
219impl ToplevelBlockOn for async_executors::AsyncStd {
220    fn block_on<F: Future>(&self, f: F) -> F::Output {
221        async_executors::AsyncStd::block_on(f)
222    }
223}
224
225impl Blocking for async_executors::AsyncStd {
226    type ThreadHandle<T: Send + 'static> = async_executors::BlockingHandle<T>;
227
228    fn spawn_blocking<F, T>(&self, f: F) -> async_executors::BlockingHandle<T>
229    where
230        F: FnOnce() -> T + Send + 'static,
231        T: Send + 'static,
232    {
233        async_executors::SpawnBlocking::spawn_blocking(&self, f)
234    }
235
236    fn reenter_block_on<F: Future>(&self, f: F) -> F::Output {
237        async_executors::AsyncStd::block_on(f)
238    }
239}
tor_rtcompat/impls/async_std.rs

tor_rtcompat/impls/
async_std.rs
