Bump to v0.16.0

* Use upstream sink compat shims
* Port to new Sink trait introduced in e101c891f04aba34ee29c6a8cd8321563c7e0161
* rustfmt
* Port to std::task::Context
* Add Google license header to bincode-transport/src/compat.rs
* Remove compat for it is no longer needed
* future::join as freestanding function
* Simplify dependencies
* Depend on futures-preview 0.3.0-alpha.14
* Fix infinite recursion

.travis.yml

@@ -9,4 +9,5 @@ os:
     - linux
 
 script:
-  - cargo test --all --all-features
+  - cargo test --all-targets --all-features
+  - cargo test --doc --all-features

README.md

@@ -1,6 +1,5 @@
 ## tarpc: Tim & Adam's RPC lib
 [![Travis-CI Status](https://travis-ci.org/google/tarpc.png?branch=master)](https://travis-ci.org/google/tarpc)
-[![Coverage Status](https://coveralls.io/repos/github/google/tarpc/badge.svg?branch=master)](https://coveralls.io/github/google/tarpc?branch=master)
 [![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg)](LICENSE)
 [![Latest Version](https://img.shields.io/crates/v/tarpc.svg)](https://crates.io/crates/tarpc)
 [![Join the chat at https://gitter.im/tarpc/Lobby](https://badges.gitter.im/tarpc/Lobby.svg)](https://gitter.im/tarpc/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
@@ -31,17 +30,12 @@ works with the community-backed library serde: any serde-serializable type can b
 arguments to tarpc fns.
 
 ## Usage
-**NB**: *this example is for master. Are you looking for other
-[versions](https://docs.rs/tarpc)?*
-
 Add to your `Cargo.toml` dependencies:
 
 ```toml
-tarpc = "0.12.0"
-tarpc-plugins = "0.4.0"
+tarpc = "0.15.0"
 ```
 
-
 The `service!` macro expands to a collection of items that form an
 rpc service. In the above example, the macro is called within the
 `hello_service` module. This module will contain a `Client` stub and `Service` trait.  There is
@@ -49,29 +43,29 @@ These generated types make it easy and ergonomic to write servers without dealin
 directly. Simply implement one of the generated traits, and you're off to the
 races!
 
-## Example:
+## Example
 
 Here's a small service.
 
 ```rust
-#![feature(plugin, futures_api, pin, arbitrary_self_types, await_macro, async_await)]
-#![plugin(tarpc_plugins)]
+#![feature(futures_api, pin, arbitrary_self_types, await_macro, async_await, proc_macro_hygiene)]
+
 
 use futures::{
-    compat::TokioDefaultSpawner,
+    compat::Executor01CompatExt,
     future::{self, Ready},
     prelude::*,
-    spawn,
 };
-use tarpc::rpc::{
+use tarpc::{
     client, context,
-    server::{self, Handler, Server},
+    server::{self, Handler},
 };
 use std::io;
 
 // This is the service definition. It looks a lot like a trait definition.
 // It defines one RPC, hello, which takes one arg, name, and returns a String.
 tarpc::service! {
+    /// Returns a greeting for name.
     rpc hello(name: String) -> String;
 }
 
@@ -86,7 +80,7 @@ impl Service for HelloServer {
 
     type HelloFut = Ready<String>;
 
-    fn hello(&self, _: context::Context, name: String) -> Self::HelloFut {
+    fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
         future::ready(format!("Hello, {}!", name))
     }
 }
@@ -98,7 +92,7 @@ async fn run() -> io::Result<()> {
     let addr = transport.local_addr();
 
     // The server is configured with the defaults.
-    let server = Server::new(server::Config::default())
+    let server = server::new(server::Config::default())
         // Server can listen on any type that implements the Transport trait.
         .incoming(transport)
         // Close the stream after the client connects
@@ -107,14 +101,14 @@ async fn run() -> io::Result<()> {
         // the generated Service trait.
         .respond_with(serve(HelloServer));
 
-    spawn!(server).unwrap();
+    tokio_executor::spawn(server.unit_error().boxed().compat());
 
     let transport = await!(bincode_transport::connect(&addr))?;
 
     // new_stub is generated by the service! macro. Like Server, it takes a config and any
     // Transport as input, and returns a Client, also generated by the macro.
     // by the service mcro.
-    let mut client = await!(new_stub(client::Config::default(), transport));
+    let mut client = await!(new_stub(client::Config::default(), transport))?;
 
     // The client has an RPC method for each RPC defined in service!. It takes the same args
     // as defined, with the addition of a Context, which is always the first arg. The Context
@@ -127,10 +121,11 @@ async fn run() -> io::Result<()> {
 }
 
 fn main() {
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
     tokio::run(run()
             .map_err(|e| eprintln!("Oh no: {}", e))
             .boxed()
-            .compat(TokioDefaultSpawner),
+            .compat(),
     );
 }
 ```
@@ -139,13 +134,3 @@ fn main() {
 
 Use `cargo doc` as you normally would to see the documentation created for all
 items expanded by a `service!` invocation.
-
-## Contributing
-
-To contribute to tarpc, please see [CONTRIBUTING](CONTRIBUTING.md).
-
-## License
-
-tarpc is distributed under the terms of the MIT license.
-
-See [LICENSE](LICENSE) for details.

bincode-transport/Cargo.toml

@@ -1,8 +1,6 @@
-cargo-features = ["rename-dependency"]
-
 [package]
 name = "tarpc-bincode-transport"
-version = "0.1.0"
+version = "0.5.0"
 authors = ["Tim Kuehn <tikue@google.com>"]
 edition = '2018'
 license = "MIT"
@@ -15,29 +13,24 @@ readme = "../README.md"
 description = "A bincode-based transport for tarpc services."
 
 [dependencies]
-bincode = { version = "1.0", features = ["i128"] }
-bytes = "0.4"
+bincode = "1"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
 futures_legacy = { version = "0.1", package = "futures" }
-pin-utils = "0.1.0-alpha.2"
-rpc = { package = "tarpc-lib", version = "0.1", path = "../rpc", features = ["serde1"] }
+pin-utils = "0.1.0-alpha.4"
+rpc = { package = "tarpc-lib", version = "0.4", path = "../rpc", features = ["serde1"] }
 serde = "1.0"
-tokio = "0.1"
 tokio-io = "0.1"
-tokio-serde-bincode = "0.1"
+async-bincode = "0.4"
 tokio-tcp = "0.1"
-tokio-serde = "0.2"
-
-[target.'cfg(not(test))'.dependencies]
-futures-preview = { version = "0.3.0-alpha.8", features = ["compat"] }
 
 [dev-dependencies]
-futures-preview = { version = "0.3.0-alpha.8", features = ["compat", "tokio-compat"] }
-env_logger = "0.5"
+env_logger = "0.6"
 humantime = "1.0"
+libtest = "0.0.1"
 log = "0.4"
-rand = "0.5"
+rand = "0.6"
 tokio = "0.1"
 tokio-executor = "0.1"
 tokio-reactor = "0.1"
-tokio-serde = "0.2"
+tokio-serde = "0.3"
 tokio-timer = "0.2"

bincode-transport/rustfmt.toml

@@ -1 +1 @@
-edition = "Edition2018"
+edition = "2018"

bincode-transport/src/lib.rs

@@ -6,79 +6,132 @@
 
 //! A TCP [`Transport`] that serializes as bincode.
 
-#![feature(
-    futures_api,
-    pin,
-    arbitrary_self_types,
-    underscore_imports,
-    await_macro,
-    async_await,
-)]
+#![feature(futures_api, arbitrary_self_types, await_macro, async_await)]
 #![deny(missing_docs, missing_debug_implementations)]
 
-mod vendored;
-
-use bytes::{Bytes, BytesMut};
-use crate::vendored::tokio_serde_bincode::{IoErrorWrapper, ReadBincode, WriteBincode};
-use futures::{
-    Poll,
-    compat::{Compat01As03, Future01CompatExt, Stream01CompatExt},
-    prelude::*,
-    ready, task,
-};
-use futures_legacy::{
-    executor::{
-        self as executor01, Notify as Notify01, NotifyHandle as NotifyHandle01,
-        UnsafeNotify as UnsafeNotify01,
-    },
-    sink::SinkMapErr as SinkMapErr01,
-    sink::With as With01,
-    stream::MapErr as MapErr01,
-    Async as Async01, AsyncSink as AsyncSink01, Sink as Sink01, Stream as Stream01,
-};
+use async_bincode::{AsyncBincodeStream, AsyncDestination};
+use futures::{compat::*, prelude::*, ready};
 use pin_utils::unsafe_pinned;
 use serde::{Deserialize, Serialize};
-use std::{fmt, io, marker::PhantomData, net::SocketAddr, pin::Pin, task::LocalWaker};
-use tokio::codec::{Framed, LengthDelimitedCodec, length_delimited};
-use tokio_tcp::{self, TcpListener, TcpStream};
+use std::{
+    error::Error,
+    io,
+    marker::PhantomData,
+    net::SocketAddr,
+    pin::Pin,
+    task::{Context, Poll},
+};
+use tokio_io::{AsyncRead, AsyncWrite};
+use tokio_tcp::{TcpListener, TcpStream};
 
-/// Returns a new bincode transport that reads from and writes to `io`.
-pub fn new<Item, SinkItem>(io: TcpStream) -> Transport<Item, SinkItem>
+/// A transport that serializes to, and deserializes from, a [`TcpStream`].
+#[derive(Debug)]
+pub struct Transport<S, Item, SinkItem> {
+    inner: Compat01As03Sink<AsyncBincodeStream<S, Item, SinkItem, AsyncDestination>, SinkItem>,
+}
+
+impl<S, Item, SinkItem> Transport<S, Item, SinkItem> {
+    unsafe_pinned!(
+        inner: Compat01As03Sink<AsyncBincodeStream<S, Item, SinkItem, AsyncDestination>, SinkItem>
+    );
+}
+
+impl<S, Item, SinkItem> Stream for Transport<S, Item, SinkItem>
 where
-    Item: for<'de> Deserialize<'de>,
-    SinkItem: Serialize,
+    S: AsyncRead,
+    Item: for<'a> Deserialize<'a>,
 {
-    let peer_addr = io.peer_addr();
-    let local_addr = io.local_addr();
-    let inner = length_delimited::Builder::new()
-        .max_frame_length(8_000_000)
-        .new_framed(io)
-        .map_err(IoErrorWrapper as _)
-        .sink_map_err(IoErrorWrapper as _)
-        .with(freeze as _);
-    let inner = WriteBincode::new(inner);
-    let inner = ReadBincode::new(inner);
+    type Item = io::Result<Item>;
 
-    Transport {
-        inner,
-        staged_item: None,
-        peer_addr,
-        local_addr,
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<io::Result<Item>>> {
+        match self.inner().poll_next(cx) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(None) => Poll::Ready(None),
+            Poll::Ready(Some(Ok(next))) => Poll::Ready(Some(Ok(next))),
+            Poll::Ready(Some(Err(e))) => {
+                Poll::Ready(Some(Err(io::Error::new(io::ErrorKind::Other, e))))
+            }
+        }
     }
 }
 
-fn freeze(bytes: BytesMut) -> Result<Bytes, IoErrorWrapper> {
-    Ok(bytes.freeze())
+impl<S, Item, SinkItem> Sink<SinkItem> for Transport<S, Item, SinkItem>
+where
+    S: AsyncWrite,
+    SinkItem: Serialize,
+{
+    type SinkError = io::Error;
+
+    fn start_send(self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
+        self.inner()
+            .start_send(item)
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+    }
+
+    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_ready(cx))
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_flush(cx))
+    }
+
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_close(cx))
+    }
 }
 
-/// Connects to `addr`, wrapping the connection in a bincode transport.
-pub async fn connect<Item, SinkItem>(addr: &SocketAddr) -> io::Result<Transport<Item, SinkItem>>
+fn convert<E: Into<Box<Error + Send + Sync>>>(poll: Poll<Result<(), E>>) -> Poll<io::Result<()>> {
+    match poll {
+        Poll::Pending => Poll::Pending,
+        Poll::Ready(Ok(())) => Poll::Ready(Ok(())),
+        Poll::Ready(Err(e)) => Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, e))),
+    }
+}
+
+impl<Item, SinkItem> rpc::Transport for Transport<TcpStream, Item, SinkItem>
 where
     Item: for<'de> Deserialize<'de>,
     SinkItem: Serialize,
 {
-    let stream = await!(TcpStream::connect(addr).compat())?;
-    Ok(new(stream))
+    type Item = Item;
+    type SinkItem = SinkItem;
+
+    fn peer_addr(&self) -> io::Result<SocketAddr> {
+        self.inner.get_ref().get_ref().peer_addr()
+    }
+
+    fn local_addr(&self) -> io::Result<SocketAddr> {
+        self.inner.get_ref().get_ref().local_addr()
+    }
+}
+
+/// Returns a new bincode transport that reads from and writes to `io`.
+pub fn new<Item, SinkItem>(io: TcpStream) -> Transport<TcpStream, Item, SinkItem>
+where
+    Item: for<'de> Deserialize<'de>,
+    SinkItem: Serialize,
+{
+    Transport::from(io)
+}
+
+impl<S, Item, SinkItem> From<S> for Transport<S, Item, SinkItem> {
+    fn from(inner: S) -> Self {
+        Transport {
+            inner: Compat01As03Sink::new(AsyncBincodeStream::from(inner).for_async()),
+        }
+    }
+}
+
+/// Connects to `addr`, wrapping the connection in a bincode transport.
+pub async fn connect<Item, SinkItem>(
+    addr: &SocketAddr,
+) -> io::Result<Transport<TcpStream, Item, SinkItem>>
+where
+    Item: for<'de> Deserialize<'de>,
+    SinkItem: Serialize,
+{
+    Ok(new(await!(TcpStream::connect(addr).compat())?))
 }
 
 /// Listens on `addr`, wrapping accepted connections in bincode transports.
@@ -119,168 +172,10 @@ where
     Item: for<'a> Deserialize<'a>,
     SinkItem: Serialize,
 {
-    type Item = io::Result<Transport<Item, SinkItem>>;
+    type Item = io::Result<Transport<TcpStream, Item, SinkItem>>;
 
-    fn poll_next(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<Self::Item>> {
-        let next = ready!(self.incoming().poll_next(waker)?);
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let next = ready!(self.incoming().poll_next(cx)?);
         Poll::Ready(next.map(|conn| Ok(new(conn))))
     }
 }
-
-/// A transport that serializes to, and deserializes from, a [`TcpStream`].
-pub struct Transport<Item, SinkItem> {
-    inner: ReadBincode<
-        WriteBincode<
-            With01<
-                SinkMapErr01<
-                    MapErr01<
-                        Framed<tokio_tcp::TcpStream, LengthDelimitedCodec>,
-                        fn(std::io::Error) -> IoErrorWrapper,
-                    >,
-                    fn(std::io::Error) -> IoErrorWrapper,
-                >,
-                BytesMut,
-                fn(BytesMut) -> Result<Bytes, IoErrorWrapper>,
-                Result<Bytes, IoErrorWrapper>
-            >,
-            SinkItem,
-        >,
-        Item,
-    >,
-    staged_item: Option<SinkItem>,
-    peer_addr: io::Result<SocketAddr>,
-    local_addr: io::Result<SocketAddr>,
-}
-
-impl<Item, SinkItem> fmt::Debug for Transport<Item, SinkItem> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Transport")
-    }
-}
-
-impl<Item, SinkItem> Stream for Transport<Item, SinkItem>
-where
-    Item: for<'a> Deserialize<'a>,
-{
-    type Item = io::Result<Item>;
-
-    fn poll_next(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<io::Result<Item>>> {
-        unsafe {
-            let inner = &mut Pin::get_mut_unchecked(self).inner;
-            let mut compat = inner.compat();
-            let compat = Pin::new_unchecked(&mut compat);
-            match ready!(compat.poll_next(waker)) {
-                None => Poll::Ready(None),
-                Some(Ok(next)) => Poll::Ready(Some(Ok(next))),
-                Some(Err(e)) => Poll::Ready(Some(Err(e.0))),
-            }
-        }
-    }
-}
-
-impl<Item, SinkItem> Sink for Transport<Item, SinkItem>
-where
-    SinkItem: Serialize,
-{
-    type SinkItem = SinkItem;
-    type SinkError = io::Error;
-
-    fn start_send(self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
-        let me = unsafe { Pin::get_mut_unchecked(self) };
-        assert!(me.staged_item.is_none());
-        me.staged_item = Some(item);
-        Ok(())
-    }
-
-    fn poll_ready(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
-        let notify = &WakerToHandle(waker);
-
-        executor01::with_notify(notify, 0, move || {
-            let me = unsafe { Pin::get_mut_unchecked(self) };
-            match me.staged_item.take() {
-                Some(staged_item) => match me.inner.start_send(staged_item)? {
-                    AsyncSink01::Ready => Poll::Ready(Ok(())),
-                    AsyncSink01::NotReady(item) => {
-                        me.staged_item = Some(item);
-                        Poll::Pending
-                    }
-                },
-                None => Poll::Ready(Ok(())),
-            }
-        })
-    }
-
-    fn poll_flush(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
-        let notify = &WakerToHandle(waker);
-
-        executor01::with_notify(notify, 0, move || {
-            let me = unsafe { Pin::get_mut_unchecked(self) };
-            match me.inner.poll_complete()? {
-                Async01::Ready(()) => Poll::Ready(Ok(())),
-                Async01::NotReady => Poll::Pending,
-            }
-        })
-    }
-
-    fn poll_close(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
-        let notify = &WakerToHandle(waker);
-
-        executor01::with_notify(notify, 0, move || {
-            let me = unsafe { Pin::get_mut_unchecked(self) };
-            match me.inner.get_mut().close()? {
-                Async01::Ready(()) => Poll::Ready(Ok(())),
-                Async01::NotReady => Poll::Pending,
-            }
-        })
-    }
-}
-
-impl<Item, SinkItem> rpc::Transport for Transport<Item, SinkItem>
-where
-    Item: for<'de> Deserialize<'de>,
-    SinkItem: Serialize,
-{
-    type Item = Item;
-    type SinkItem = SinkItem;
-
-    fn peer_addr(&self) -> io::Result<SocketAddr> {
-        // TODO: should just access from the inner transport.
-        // https://github.com/alexcrichton/tokio-serde-bincode/issues/4
-        Ok(*self.peer_addr.as_ref().unwrap())
-    }
-
-    fn local_addr(&self) -> io::Result<SocketAddr> {
-        Ok(*self.local_addr.as_ref().unwrap())
-    }
-}
-
-#[derive(Clone, Debug)]
-struct WakerToHandle<'a>(&'a LocalWaker);
-
-#[derive(Debug)]
-struct NotifyWaker(task::Waker);
-
-impl Notify01 for NotifyWaker {
-    fn notify(&self, _: usize) {
-        self.0.wake();
-    }
-}
-
-unsafe impl UnsafeNotify01 for NotifyWaker {
-    unsafe fn clone_raw(&self) -> NotifyHandle01 {
-        let ptr = Box::new(NotifyWaker(self.0.clone()));
-
-        NotifyHandle01::new(Box::into_raw(ptr))
-    }
-
-    unsafe fn drop_raw(&self) {
-        let ptr: *const dyn UnsafeNotify01 = self;
-        drop(Box::from_raw(ptr as *mut dyn UnsafeNotify01));
-    }
-}
-
-impl<'a> From<WakerToHandle<'a>> for NotifyHandle01 {
-    fn from(handle: WakerToHandle<'a>) -> NotifyHandle01 {
-        unsafe { NotifyWaker(handle.0.clone().into_waker()).clone_raw() }
-    }
-}

bincode-transport/src/vendored/mod.rs

@@ -1,7 +0,0 @@
-// Copyright 2018 Google LLC
-//
-// Use of this source code is governed by an MIT-style
-// license that can be found in the LICENSE file or at
-// https://opensource.org/licenses/MIT.
-
-pub(crate) mod tokio_serde_bincode;

bincode-transport/src/vendored/tokio_serde_bincode.rs

@@ -1,224 +0,0 @@
-//! `Stream` and `Sink` adaptors for serializing and deserializing values using
-//! Bincode.
-//!
-//! This crate provides adaptors for going from a stream or sink of buffers
-//! ([`Bytes`]) to a stream or sink of values by performing Bincode encoding or
-//! decoding. It is expected that each yielded buffer contains a single
-//! serialized Bincode value. The specific strategy by which this is done is left
-//! up to the user. One option is to use using [`length_delimited`] from
-//! [tokio-io].
-//!
-//! [`Bytes`]: https://docs.rs/bytes/0.4/bytes/struct.Bytes.html
-//! [`length_delimited`]: http://alexcrichton.com/tokio-io/tokio_io/codec/length_delimited/index.html
-//! [tokio-io]: http://github.com/alexcrichton/tokio-io
-//! [examples]: https://github.com/carllerche/tokio-serde-json/tree/master/examples
-
-#![allow(missing_debug_implementations)]
-
-use bincode::Error;
-use bytes::{Bytes, BytesMut};
-use futures_legacy::{Poll, Sink, StartSend, Stream};
-use serde::{Deserialize, Serialize};
-use std::io;
-use tokio_serde::{Deserializer, FramedRead, FramedWrite, Serializer};
-
-use std::marker::PhantomData;
-
-/// Adapts a stream of Bincode encoded buffers to a stream of values by
-/// deserializing them.
-///
-/// `ReadBincode` implements `Stream` by polling the inner buffer stream and
-/// deserializing the buffer as Bincode. It expects that each yielded buffer
-/// represents a single Bincode value and does not contain any extra trailing
-/// bytes.
-pub(crate) struct ReadBincode<T, U> {
-    inner: FramedRead<T, U, Bincode<U>>,
-}
-
-/// Adapts a buffer sink to a value sink by serializing the values as Bincode.
-///
-/// `WriteBincode` implements `Sink` by serializing the submitted values to a
-/// buffer. The buffer is then sent to the inner stream, which is responsible
-/// for handling framing on the wire.
-pub(crate) struct WriteBincode<T: Sink, U> {
-    inner: FramedWrite<T, U, Bincode<U>>,
-}
-
-struct Bincode<T> {
-    ghost: PhantomData<T>,
-}
-
-impl<T, U> ReadBincode<T, U>
-where
-    T: Stream<Error = IoErrorWrapper>,
-    U: for<'de> Deserialize<'de>,
-    Bytes: From<T::Item>,
-{
-    /// Creates a new `ReadBincode` with the given buffer stream.
-    pub fn new(inner: T) -> ReadBincode<T, U> {
-        let json = Bincode { ghost: PhantomData };
-        ReadBincode {
-            inner: FramedRead::new(inner, json),
-        }
-    }
-}
-
-impl<T, U> ReadBincode<T, U> {
-    /// Returns a mutable reference to the underlying stream wrapped by
-    /// `ReadBincode`.
-    ///
-    /// Note that care should be taken to not tamper with the underlying stream
-    /// of data coming in as it may corrupt the stream of frames otherwise
-    /// being worked with.
-    pub fn get_mut(&mut self) -> &mut T {
-        self.inner.get_mut()
-    }
-}
-
-impl<T, U> Stream for ReadBincode<T, U>
-where
-    T: Stream<Error = IoErrorWrapper>,
-    U: for<'de> Deserialize<'de>,
-    Bytes: From<T::Item>,
-{
-    type Item = U;
-    type Error = <T as Stream>::Error;
-
-    fn poll(&mut self) -> Poll<Option<U>, Self::Error> {
-        self.inner.poll()
-    }
-}
-
-impl<T, U> Sink for ReadBincode<T, U>
-where
-    T: Sink,
-{
-    type SinkItem = T::SinkItem;
-    type SinkError = T::SinkError;
-
-    fn start_send(&mut self, item: T::SinkItem) -> StartSend<T::SinkItem, T::SinkError> {
-        self.get_mut().start_send(item)
-    }
-
-    fn poll_complete(&mut self) -> Poll<(), T::SinkError> {
-        self.get_mut().poll_complete()
-    }
-
-    fn close(&mut self) -> Poll<(), T::SinkError> {
-        self.get_mut().close()
-    }
-}
-
-pub(crate) struct IoErrorWrapper(pub io::Error);
-impl From<Box<bincode::ErrorKind>> for IoErrorWrapper {
-    fn from(e: Box<bincode::ErrorKind>) -> Self {
-        IoErrorWrapper(match *e {
-            bincode::ErrorKind::Io(e) => e,
-            bincode::ErrorKind::InvalidUtf8Encoding(e) => {
-                io::Error::new(io::ErrorKind::InvalidInput, e)
-            }
-            bincode::ErrorKind::InvalidBoolEncoding(e) => {
-                io::Error::new(io::ErrorKind::InvalidInput, e.to_string())
-            }
-            bincode::ErrorKind::InvalidTagEncoding(e) => {
-                io::Error::new(io::ErrorKind::InvalidInput, e.to_string())
-            }
-            bincode::ErrorKind::InvalidCharEncoding => {
-                io::Error::new(io::ErrorKind::InvalidInput, "Invalid char encoding")
-            }
-            bincode::ErrorKind::DeserializeAnyNotSupported => {
-                io::Error::new(io::ErrorKind::InvalidInput, "Deserialize Any not supported")
-            }
-            bincode::ErrorKind::SizeLimit => {
-                io::Error::new(io::ErrorKind::InvalidInput, "Size limit exceeded")
-            }
-            bincode::ErrorKind::SequenceMustHaveLength => {
-                io::Error::new(io::ErrorKind::InvalidInput, "Sequence must have length")
-            }
-            bincode::ErrorKind::Custom(s) => io::Error::new(io::ErrorKind::Other, s),
-        })
-    }
-}
-
-impl From<IoErrorWrapper> for io::Error {
-    fn from(wrapper: IoErrorWrapper) -> io::Error {
-        wrapper.0
-    }
-}
-
-impl<T, U> WriteBincode<T, U>
-where
-    T: Sink<SinkItem = BytesMut, SinkError = IoErrorWrapper>,
-    U: Serialize,
-{
-    /// Creates a new `WriteBincode` with the given buffer sink.
-    pub fn new(inner: T) -> WriteBincode<T, U> {
-        let json = Bincode { ghost: PhantomData };
-        WriteBincode {
-            inner: FramedWrite::new(inner, json),
-        }
-    }
-}
-
-impl<T: Sink, U> WriteBincode<T, U> {
-    /// Returns a mutable reference to the underlying sink wrapped by
-    /// `WriteBincode`.
-    ///
-    /// Note that care should be taken to not tamper with the underlying sink as
-    /// it may corrupt the sequence of frames otherwise being worked with.
-    pub fn get_mut(&mut self) -> &mut T {
-        self.inner.get_mut()
-    }
-}
-
-impl<T, U> Sink for WriteBincode<T, U>
-where
-    T: Sink<SinkItem = BytesMut, SinkError = IoErrorWrapper>,
-    U: Serialize,
-{
-    type SinkItem = U;
-    type SinkError = <T as Sink>::SinkError;
-
-    fn start_send(&mut self, item: U) -> StartSend<U, Self::SinkError> {
-        self.inner.start_send(item)
-    }
-
-    fn poll_complete(&mut self) -> Poll<(), Self::SinkError> {
-        self.inner.poll_complete()
-    }
-
-    fn close(&mut self) -> Poll<(), Self::SinkError> {
-        self.inner.poll_complete()
-    }
-}
-
-impl<T, U> Stream for WriteBincode<T, U>
-where
-    T: Stream + Sink,
-{
-    type Item = T::Item;
-    type Error = T::Error;
-
-    fn poll(&mut self) -> Poll<Option<T::Item>, T::Error> {
-        self.get_mut().poll()
-    }
-}
-
-impl<T> Deserializer<T> for Bincode<T>
-where
-    T: for<'de> Deserialize<'de>,
-{
-    type Error = Error;
-
-    fn deserialize(&mut self, src: &Bytes) -> Result<T, Error> {
-        bincode::deserialize(src)
-    }
-}
-
-impl<T: Serialize> Serializer<T> for Bincode<T> {
-    type Error = Error;
-
-    fn serialize(&mut self, item: &T) -> Result<BytesMut, Self::Error> {
-        bincode::serialize(item).map(Into::into)
-    }
-}

bincode-transport/tests/bench.rs

@@ -15,14 +15,11 @@
     async_await
 )]
 
-extern crate test;
-
-use self::test::stats::Stats;
-use futures::{compat::TokioDefaultSpawner, prelude::*};
+use futures::{compat::Executor01CompatExt, prelude::*};
+use libtest::stats::Stats;
 use rpc::{
-    client::{self, Client},
-    context,
-    server::{self, Handler, Server},
+    client, context,
+    server::{Handler, Server},
 };
 use std::{
     io,
@@ -34,17 +31,17 @@ async fn bench() -> io::Result<()> {
     let addr = listener.local_addr();
 
     tokio_executor::spawn(
-        Server::<u32, u32>::new(server::Config::default())
+        Server::<u32, u32>::default()
             .incoming(listener)
             .take(1)
             .respond_with(|_ctx, request| futures::future::ready(Ok(request)))
             .unit_error()
             .boxed()
-            .compat()
+            .compat(),
     );
 
     let conn = await!(tarpc_bincode_transport::connect(&addr))?;
-    let client = &mut await!(Client::<u32, u32>::new(client::Config::default(), conn))?;
+    let client = &mut await!(client::new::<u32, u32, _>(client::Config::default(), conn))?;
 
     let total = 10_000usize;
     let mut successful = 0u32;
@@ -102,14 +99,9 @@ async fn bench() -> io::Result<()> {
 #[test]
 fn bench_small_packet() -> io::Result<()> {
     env_logger::init();
-    rpc::init(TokioDefaultSpawner);
+    rpc::init(tokio::executor::DefaultExecutor::current().compat());
 
-    tokio::run(
-        bench()
-            .map_err(|e| panic!(e.to_string()))
-            .boxed()
-            .compat(),
-    );
+    tokio::run(bench().map_err(|e| panic!(e.to_string())).boxed().compat());
     println!("done");
 
     Ok(())

bincode-transport/tests/cancel.rs

@@ -6,20 +6,16 @@
 
 //! Tests client/server control flow.
 
-#![feature(generators, await_macro, async_await, futures_api,)]
+#![feature(generators, await_macro, async_await, futures_api)]
 
 use futures::{
-    compat::{Future01CompatExt, TokioDefaultSpawner},
+    compat::{Executor01CompatExt, Future01CompatExt},
     prelude::*,
-    stream,
+    stream::FuturesUnordered,
 };
 use log::{info, trace};
 use rand::distributions::{Distribution, Normal};
-use rpc::{
-    client::{self, Client},
-    context,
-    server::{self, Server},
-};
+use rpc::{client, context, server::Server};
 use std::{
     io,
     time::{Duration, Instant, SystemTime},
@@ -40,7 +36,7 @@ impl AsDuration for SystemTime {
 async fn run() -> io::Result<()> {
     let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
     let addr = listener.local_addr();
-    let server = Server::<String, String>::new(server::Config::default())
+    let server = Server::<String, String>::default()
         .incoming(listener)
         .take(1)
         .for_each(async move |channel| {
@@ -80,7 +76,7 @@ async fn run() -> io::Result<()> {
     tokio_executor::spawn(server.unit_error().boxed().compat());
 
     let conn = await!(tarpc_bincode_transport::connect(&addr))?;
-    let client = await!(Client::<String, String>::new(
+    let client = await!(client::new::<String, String, _>(
         client::Config::default(),
         conn
     ))?;
@@ -88,7 +84,7 @@ async fn run() -> io::Result<()> {
     // Proxy service
     let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
     let addr = listener.local_addr();
-    let proxy_server = Server::<String, String>::new(server::Config::default())
+    let proxy_server = Server::<String, String>::default()
         .incoming(listener)
         .take(1)
         .for_each(move |channel| {
@@ -115,7 +111,7 @@ async fn run() -> io::Result<()> {
     config.max_in_flight_requests = 10;
     config.pending_request_buffer = 10;
 
-    let client = await!(Client::<String, String>::new(
+    let client = await!(client::new::<String, String, _>(
         config,
         await!(tarpc_bincode_transport::connect(&addr))?
     ))?;
@@ -130,7 +126,10 @@ async fn run() -> io::Result<()> {
         let response = client.call(ctx, "ping".into());
         requests.push(response.map(move |r| (trace_id, r)));
     }
-    let (fastest_response, _) = await!(stream::futures_unordered(requests).into_future());
+    let (fastest_response, _) = await!(requests
+        .into_iter()
+        .collect::<FuturesUnordered<_>>()
+        .into_future());
     let (trace_id, resp) = fastest_response.unwrap();
     info!("[{}] fastest_response = {:?}", trace_id, resp);
 
@@ -140,13 +139,8 @@ async fn run() -> io::Result<()> {
 #[test]
 fn cancel_slower() -> io::Result<()> {
     env_logger::init();
-    rpc::init(TokioDefaultSpawner);
+    rpc::init(tokio::executor::DefaultExecutor::current().compat());
 
-    tokio::run(
-        run()
-            .boxed()
-            .map_err(|e| panic!(e))
-            .compat(),
-    );
+    tokio::run(run().boxed().map_err(|e| panic!(e)).compat());
     Ok(())
 }

bincode-transport/tests/pushback.rs

@@ -6,19 +6,15 @@
 
 //! Tests client/server control flow.
 
-#![feature(generators, await_macro, async_await, futures_api,)]
+#![feature(generators, await_macro, async_await, futures_api)]
 
 use futures::{
-    compat::{Future01CompatExt, TokioDefaultSpawner},
+    compat::{Executor01CompatExt, Future01CompatExt},
     prelude::*,
 };
 use log::{error, info, trace};
 use rand::distributions::{Distribution, Normal};
-use rpc::{
-    client::{self, Client},
-    context,
-    server::{self, Server},
-};
+use rpc::{client, context, server::Server};
 use std::{
     io,
     time::{Duration, Instant, SystemTime},
@@ -39,7 +35,7 @@ impl AsDuration for SystemTime {
 async fn run() -> io::Result<()> {
     let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
     let addr = listener.local_addr();
-    let server = Server::<String, String>::new(server::Config::default())
+    let server = Server::<String, String>::default()
         .incoming(listener)
         .take(1)
         .for_each(async move |channel| {
@@ -83,7 +79,7 @@ async fn run() -> io::Result<()> {
     config.pending_request_buffer = 10;
 
     let conn = await!(tarpc_bincode_transport::connect(&addr))?;
-    let client = await!(Client::<String, String>::new(config, conn))?;
+    let client = await!(client::new::<String, String, _>(config, conn))?;
 
     let clients = (1..=100u32).map(|_| client.clone()).collect::<Vec<_>>();
     for mut client in clients {
@@ -96,7 +92,10 @@ async fn run() -> io::Result<()> {
                     Ok(response) => info!("[{}] response: {}", trace_id, response),
                     Err(e) => error!("[{}] request error: {:?}: {}", trace_id, e.kind(), e),
                 }
-            }.unit_error().boxed().compat()
+            }
+                .unit_error()
+                .boxed()
+                .compat(),
         );
     }
 
@@ -106,7 +105,7 @@ async fn run() -> io::Result<()> {
 #[test]
 fn ping_pong() -> io::Result<()> {
     env_logger::init();
-    rpc::init(TokioDefaultSpawner);
+    rpc::init(tokio::executor::DefaultExecutor::current().compat());
 
     tokio::run(
         run()

example-service/Cargo.toml

@@ -1,24 +1,23 @@
-cargo-features = ["rename-dependency"]
-
 [package]
 name = "tarpc-example-service"
-version = "0.1.0"
+version = "0.4.0"
 authors = ["Tim Kuehn <tikue@google.com>"]
 edition = "2018"
 license = "MIT"
 documentation = "https://docs.rs/tarpc-example-service"
 homepage = "https://github.com/google/tarpc"
 repository = "https://github.com/google/tarpc"
-keywords = ["rpc", "network", "server", "api", "microservices", "example"]
+keywords = ["rpc", "network", "server", "microservices", "example"]
 categories = ["asynchronous", "network-programming"]
 readme = "../README.md"
 description = "An example server built on tarpc."
 
 [dependencies]
-bincode-transport = { package = "tarpc-bincode-transport", version = "0.1", path = "../bincode-transport" }
-futures-preview = { version = "0.3.0-alpha.8", features = ["compat", "tokio-compat"] }
+bincode-transport = { package = "tarpc-bincode-transport", version = "0.5", path = "../bincode-transport" }
+clap = "2.0"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
 serde = { version = "1.0" }
-tarpc = { version = "0.13", path = "../tarpc", features = ["serde1"] }
+tarpc = { version = "0.16", path = "../tarpc", features = ["serde1"] }
 tokio = "0.1"
 tokio-executor = "0.1"
 
@@ -28,4 +27,8 @@ path = "src/lib.rs"
 
 [[bin]]
 name = "server"
-path = "src/main.rs"
+path = "src/server.rs"
+
+[[bin]]
+name = "client"
+path = "src/client.rs"

example-service/src/client.rs

@@ -0,0 +1,73 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(futures_api, arbitrary_self_types, await_macro, async_await)]
+
+use clap::{App, Arg};
+use futures::{compat::Executor01CompatExt, prelude::*};
+use std::{io, net::SocketAddr};
+use tarpc::{client, context};
+
+async fn run(server_addr: SocketAddr, name: String) -> io::Result<()> {
+    let transport = await!(bincode_transport::connect(&server_addr))?;
+
+    // new_stub is generated by the service! macro. Like Server, it takes a config and any
+    // Transport as input, and returns a Client, also generated by the macro.
+    // by the service mcro.
+    let mut client = await!(service::new_stub(client::Config::default(), transport))?;
+
+    // The client has an RPC method for each RPC defined in service!. It takes the same args
+    // as defined, with the addition of a Context, which is always the first arg. The Context
+    // specifies a deadline and trace information which can be helpful in debugging requests.
+    let hello = await!(client.hello(context::current(), name))?;
+
+    println!("{}", hello);
+
+    Ok(())
+}
+
+fn main() {
+    let flags = App::new("Hello Client")
+        .version("0.1")
+        .author("Tim <tikue@google.com>")
+        .about("Say hello!")
+        .arg(
+            Arg::with_name("server_addr")
+                .long("server_addr")
+                .value_name("ADDRESS")
+                .help("Sets the server address to connect to.")
+                .required(true)
+                .takes_value(true),
+        )
+        .arg(
+            Arg::with_name("name")
+                .short("n")
+                .long("name")
+                .value_name("STRING")
+                .help("Sets the name to say hello to.")
+                .required(true)
+                .takes_value(true),
+        )
+        .get_matches();
+
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+
+    let server_addr = flags.value_of("server_addr").unwrap();
+    let server_addr = server_addr
+        .parse()
+        .unwrap_or_else(|e| panic!(r#"--server_addr value "{}" invalid: {}"#, server_addr, e));
+
+    let name = flags.value_of("name").unwrap();
+
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(
+        run(server_addr, name.into())
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

example-service/src/lib.rs

@@ -6,11 +6,10 @@
 
 #![feature(
     futures_api,
-    pin,
     arbitrary_self_types,
     await_macro,
     async_await,
-    proc_macro_hygiene,
+    proc_macro_hygiene
 )]
 
 // This is the service definition. It looks a lot like a trait definition.

example-service/src/main.rs

@@ -1,85 +0,0 @@
-// Copyright 2018 Google LLC
-//
-// Use of this source code is governed by an MIT-style
-// license that can be found in the LICENSE file or at
-// https://opensource.org/licenses/MIT.
-
-#![feature(
-    futures_api,
-    pin,
-    arbitrary_self_types,
-    await_macro,
-    async_await,
-)]
-
-use futures::{
-    compat::TokioDefaultSpawner,
-    future::{self, Ready},
-    prelude::*,
-};
-use tarpc::{
-    client, context,
-    server::{self, Handler, Server},
-};
-use std::io;
-
-// This is the type that implements the generated Service trait. It is the business logic
-// and is used to start the server.
-#[derive(Clone)]
-struct HelloServer;
-
-impl service::Service for HelloServer {
-    // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
-    // an associated type representing the future output by the fn.
-
-    type HelloFut = Ready<String>;
-
-    fn hello(&self, _: context::Context, name: String) -> Self::HelloFut {
-        future::ready(format!("Hello, {}!", name))
-    }
-}
-
-async fn run() -> io::Result<()> {
-    // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
-    // to start up a serde-powered bincode serialization strategy over TCP.
-    let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
-    let addr = transport.local_addr();
-
-    // The server is configured with the defaults.
-    let server = Server::new(server::Config::default())
-        // Server can listen on any type that implements the Transport trait.
-        .incoming(transport)
-        // Close the stream after the client connects
-        .take(1)
-        // serve is generated by the service! macro. It takes as input any type implementing
-        // the generated Service trait.
-        .respond_with(service::serve(HelloServer));
-
-    tokio_executor::spawn(server.unit_error().boxed().compat());
-
-    let transport = await!(bincode_transport::connect(&addr))?;
-
-    // new_stub is generated by the service! macro. Like Server, it takes a config and any
-    // Transport as input, and returns a Client, also generated by the macro.
-    // by the service mcro.
-    let mut client = await!(service::new_stub(client::Config::default(), transport))?;
-
-    // The client has an RPC method for each RPC defined in service!. It takes the same args
-    // as defined, with the addition of a Context, which is always the first arg. The Context
-    // specifies a deadline and trace information which can be helpful in debugging requests.
-    let hello = await!(client.hello(context::current(), "Stim".to_string()))?;
-
-    println!("{}", hello);
-
-    Ok(())
-}
-
-fn main() {
-    tarpc::init(TokioDefaultSpawner);
-
-    tokio::run(run()
-            .map_err(|e| eprintln!("Oh no: {}", e))
-            .boxed()
-            .compat()
-    );
-}

example-service/src/server.rs

@@ -0,0 +1,84 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(futures_api, arbitrary_self_types, await_macro, async_await)]
+
+use clap::{App, Arg};
+use futures::{
+    compat::Executor01CompatExt,
+    future::{self, Ready},
+    prelude::*,
+};
+use std::{io, net::SocketAddr};
+use tarpc::{
+    context,
+    server::{Handler, Server},
+};
+
+// This is the type that implements the generated Service trait. It is the business logic
+// and is used to start the server.
+#[derive(Clone)]
+struct HelloServer;
+
+impl service::Service for HelloServer {
+    // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
+    // an associated type representing the future output by the fn.
+
+    type HelloFut = Ready<String>;
+
+    fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
+        future::ready(format!("Hello, {}!", name))
+    }
+}
+
+async fn run(server_addr: SocketAddr) -> io::Result<()> {
+    // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
+    // to start up a serde-powered bincode serialization strategy over TCP.
+    let transport = bincode_transport::listen(&server_addr)?;
+
+    // The server is configured with the defaults.
+    let server = Server::default()
+        // Server can listen on any type that implements the Transport trait.
+        .incoming(transport)
+        // serve is generated by the service! macro. It takes as input any type implementing
+        // the generated Service trait.
+        .respond_with(service::serve(HelloServer));
+
+    await!(server);
+
+    Ok(())
+}
+
+fn main() {
+    let flags = App::new("Hello Server")
+        .version("0.1")
+        .author("Tim <tikue@google.com>")
+        .about("Say hello!")
+        .arg(
+            Arg::with_name("port")
+                .short("p")
+                .long("port")
+                .value_name("NUMBER")
+                .help("Sets the port number to listen on")
+                .required(true)
+                .takes_value(true),
+        )
+        .get_matches();
+
+    let port = flags.value_of("port").unwrap();
+    let port = port
+        .parse()
+        .unwrap_or_else(|e| panic!(r#"--port value "{}" invalid: {}"#, port, e));
+
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(
+        run(([0, 0, 0, 0], port).into())
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

hooks/pre-commit

@@ -96,7 +96,7 @@ do
         diff="$diff$(cargo fmt -- --skip-children --write-mode=diff $file)"
 	fi
 done
-if grep --quiet "^Diff at line" <<< "$diff"; then
+if grep --quiet "^[-+]" <<< "$diff"; then
     FMTRESULT=1
 fi
 

plugins/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tarpc-plugins"
-version = "0.5.0"
+version = "0.5.1"
 authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
 license = "MIT"
 documentation = "https://docs.rs/tarpc-plugins"
@@ -15,7 +15,7 @@ description = "Proc macros for tarpc."
 travis-ci = { repository = "google/tarpc" }
 
 [dependencies]
-itertools = "0.7"
+itertools = "0.8"
 syn = { version = "0.15", features = ["full", "extra-traits"] }
 quote = "0.6"
 proc-macro2 = "0.4"

plugins/rustfmt.toml

@@ -1 +1 @@
-edition = "Edition2018"
+edition = "2018"

plugins/src/lib.rs

@@ -4,31 +4,35 @@
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+extern crate itertools;
 extern crate proc_macro;
 extern crate proc_macro2;
-extern crate syn;
-extern crate itertools;
 extern crate quote;
+extern crate syn;
 
 use proc_macro::TokenStream;
 
 use itertools::Itertools;
-use quote::ToTokens;
-use syn::{Ident, TraitItemType, TypePath, parse};
 use proc_macro2::Span;
+use quote::ToTokens;
 use std::str::FromStr;
+use syn::{parse, Ident, TraitItemType, TypePath};
 
 #[proc_macro]
 pub fn snake_to_camel(input: TokenStream) -> TokenStream {
     let i = input.clone();
-    let mut assoc_type = parse::<TraitItemType>(input).unwrap_or_else(|_| panic!("Could not parse trait item from:\n{}", i));
+    let mut assoc_type = parse::<TraitItemType>(input)
+        .unwrap_or_else(|_| panic!("Could not parse trait item from:\n{}", i));
 
     let old_ident = convert(&mut assoc_type.ident);
 
     for mut attr in &mut assoc_type.attrs {
         if let Some(pair) = attr.path.segments.first() {
             if pair.value().ident == "doc" {
-                attr.tts = proc_macro2::TokenStream::from_str(&attr.tts.to_string().replace("{}", &old_ident)).unwrap();
+                attr.tts = proc_macro2::TokenStream::from_str(
+                    &attr.tts.to_string().replace("{}", &old_ident),
+                )
+                .unwrap();
             }
         }
     }
@@ -41,12 +45,7 @@ pub fn ty_snake_to_camel(input: TokenStream) -> TokenStream {
     let mut path = parse::<TypePath>(input).unwrap();
 
     // Only capitalize the final segment
-    convert(&mut path.path
-                     .segments
-                     .last_mut()
-                     .unwrap()
-                     .into_value()
-                     .ident);
+    convert(&mut path.path.segments.last_mut().unwrap().into_value().ident);
 
     path.into_token_stream().into()
 }

rpc/Cargo.toml

@@ -1,8 +1,6 @@
-cargo-features = ["rename-dependency"]
-
 [package]
 name = "tarpc-lib"
-version = "0.1.0"
+version = "0.4.0"
 authors = ["Tim Kuehn <tikue@google.com>"]
 edition = '2018'
 license = "MIT"
@@ -20,19 +18,16 @@ serde1 = ["trace/serde", "serde", "serde/derive"]
 
 [dependencies]
 fnv = "1.0"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
 humantime = "1.0"
 log = "0.4"
-pin-utils = "0.1.0-alpha.2"
-rand = "0.5"
+pin-utils = "0.1.0-alpha.4"
+rand = "0.6"
 tokio-timer = "0.2"
-trace = { package = "tarpc-trace", version = "0.1", path = "../trace" }
+trace = { package = "tarpc-trace", version = "0.2", path = "../trace" }
 serde = { optional = true, version = "1.0" }
 
-[target.'cfg(not(test))'.dependencies]
-futures-preview = { version = "0.3.0-alpha.8", features = ["compat"] }
-
 [dev-dependencies]
-futures-preview = { version = "0.3.0-alpha.8", features = ["compat", "tokio-compat"] }
-futures-test-preview = { version = "0.3.0-alpha.8" }
-env_logger = "0.5"
+futures-test-preview = { version = "0.3.0-alpha.14" }
+env_logger = "0.6"
 tokio = "0.1"

rpc/rustfmt.toml

@@ -1 +1 @@
-edition = "Edition2018"
+edition = "2018"

rpc/src/client/channel.rs

@@ -7,22 +7,23 @@
 use crate::{
     context,
     util::{deadline_compat, AsDuration, Compact},
-    ClientMessage, ClientMessageKind, Request, Response, Transport,
+    ClientMessage, ClientMessageKind, PollIo, Request, Response, Transport,
 };
 use fnv::FnvHashMap;
 use futures::{
-    Poll,
     channel::{mpsc, oneshot},
     prelude::*,
     ready,
     stream::Fuse,
-    task::LocalWaker,
+    task::Context,
+    Poll,
 };
 use humantime::format_rfc3339;
 use log::{debug, error, info, trace};
-use pin_utils::unsafe_pinned;
+use pin_utils::{unsafe_pinned, unsafe_unpinned};
 use std::{
     io,
+    marker::{self, Unpin},
     net::SocketAddr,
     pin::Pin,
     sync::{
@@ -37,7 +38,7 @@ use super::Config;
 
 /// Handles communication from the client to request dispatch.
 #[derive(Debug)]
-pub(crate) struct Channel<Req, Resp> {
+pub struct Channel<Req, Resp> {
     to_dispatch: mpsc::Sender<DispatchRequest<Req, Resp>>,
     /// Channel to send a cancel message to the dispatcher.
     cancellation: RequestCancellation,
@@ -57,14 +58,63 @@ impl<Req, Resp> Clone for Channel<Req, Resp> {
     }
 }
 
+/// A future returned by [`Channel::send`] that resolves to a server response.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct Send<'a, Req, Resp> {
+    fut: MapOkDispatchResponse<SendMapErrConnectionReset<'a, Req, Resp>, Resp>,
+}
+
+type SendMapErrConnectionReset<'a, Req, Resp> = MapErrConnectionReset<
+    futures::sink::Send<'a, mpsc::Sender<DispatchRequest<Req, Resp>>, DispatchRequest<Req, Resp>>,
+>;
+
+impl<'a, Req, Resp> Send<'a, Req, Resp> {
+    unsafe_pinned!(
+        fut: MapOkDispatchResponse<
+            MapErrConnectionReset<
+                futures::sink::Send<
+                    'a,
+                    mpsc::Sender<DispatchRequest<Req, Resp>>,
+                    DispatchRequest<Req, Resp>,
+                >,
+            >,
+            Resp,
+        >
+    );
+}
+
+impl<'a, Req, Resp> Future for Send<'a, Req, Resp> {
+    type Output = io::Result<DispatchResponse<Resp>>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.as_mut().fut().poll(cx)
+    }
+}
+
+/// A future returned by [`Channel::call`] that resolves to a server response.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+pub struct Call<'a, Req, Resp> {
+    fut: AndThenIdent<Send<'a, Req, Resp>, DispatchResponse<Resp>>,
+}
+
+impl<'a, Req, Resp> Call<'a, Req, Resp> {
+    unsafe_pinned!(fut: AndThenIdent<Send<'a, Req, Resp>, DispatchResponse<Resp>>);
+}
+
+impl<'a, Req, Resp> Future for Call<'a, Req, Resp> {
+    type Output = io::Result<Resp>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.as_mut().fut().poll(cx)
+    }
+}
+
 impl<Req, Resp> Channel<Req, Resp> {
     /// Sends a request to the dispatch task to forward to the server, returning a [`Future`] that
     /// resolves when the request is sent (not when the response is received).
-    pub(crate) async fn send(
-        &mut self,
-        mut ctx: context::Context,
-        request: Req,
-    ) -> io::Result<DispatchResponse<Resp>> {
+    fn send(&mut self, mut ctx: context::Context, request: Req) -> Send<Req, Resp> {
         // Convert the context to the call context.
         ctx.trace_context.parent_id = Some(ctx.trace_context.span_id);
         ctx.trace_context.span_id = SpanId::random(&mut rand::thread_rng());
@@ -82,38 +132,40 @@ impl<Req, Resp> Channel<Req, Resp> {
         let (response_completion, response) = oneshot::channel();
         let cancellation = self.cancellation.clone();
         let request_id = self.next_request_id.fetch_add(1, Ordering::Relaxed);
-        await!(self.to_dispatch.send(DispatchRequest {
-            ctx,
-            request_id,
-            request,
-            response_completion,
-        })).map_err(|_| io::Error::from(io::ErrorKind::ConnectionReset))?;
-        Ok(DispatchResponse {
-            response: deadline_compat::Deadline::new(response, deadline),
-            complete: false,
-            request_id,
-            cancellation,
-            ctx,
-            server_addr: self.server_addr,
-        })
+        let server_addr = self.server_addr;
+        Send {
+            fut: MapOkDispatchResponse::new(
+                MapErrConnectionReset::new(self.to_dispatch.send(DispatchRequest {
+                    ctx,
+                    request_id,
+                    request,
+                    response_completion,
+                })),
+                DispatchResponse {
+                    response: deadline_compat::Deadline::new(response, deadline),
+                    complete: false,
+                    request_id,
+                    cancellation,
+                    ctx,
+                    server_addr,
+                },
+            ),
+        }
     }
 
     /// Sends a request to the dispatch task to forward to the server, returning a [`Future`] that
     /// resolves to the response.
-    pub(crate) async fn call(
-        &mut self,
-        context: context::Context,
-        request: Req,
-    ) -> io::Result<Resp> {
-        let response_future = await!(self.send(context, request))?;
-        await!(response_future)
+    pub fn call(&mut self, context: context::Context, request: Req) -> Call<Req, Resp> {
+        Call {
+            fut: AndThenIdent::new(self.send(context, request)),
+        }
     }
 }
 
 /// A server response that is completed by request dispatch when the corresponding response
 /// arrives off the wire.
 #[derive(Debug)]
-pub struct DispatchResponse<Resp> {
+struct DispatchResponse<Resp> {
     response: deadline_compat::Deadline<oneshot::Receiver<Response<Resp>>>,
     ctx: context::Context,
     complete: bool,
@@ -130,16 +182,16 @@ impl<Resp> DispatchResponse<Resp> {
 impl<Resp> Future for DispatchResponse<Resp> {
     type Output = io::Result<Resp>;
 
-    fn poll(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<Resp>> {
-        let resp = ready!(self.response.poll_unpin(waker));
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<Resp>> {
+        let resp = ready!(self.response.poll_unpin(cx));
 
         self.complete = true;
 
         Poll::Ready(match resp {
             Ok(resp) => Ok(resp.message?),
             Err(e) => Err({
-                let trace_id = *self.ctx().trace_id();
-                let server_addr = *self.server_addr();
+                let trace_id = *self.as_mut().ctx().trace_id();
+                let server_addr = *self.as_mut().server_addr();
 
                 if e.is_elapsed() {
                     io::Error::new(
@@ -205,12 +257,13 @@ pub async fn spawn<Req, Resp, C>(
     server_addr: SocketAddr,
 ) -> io::Result<Channel<Req, Resp>>
 where
-    Req: Send,
-    Resp: Send,
-    C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>> + Send,
+    Req: marker::Send + 'static,
+    Resp: marker::Send + 'static,
+    C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>> + marker::Send + 'static,
 {
     let (to_dispatch, pending_requests) = mpsc::channel(config.pending_request_buffer);
     let (cancellation, canceled_requests) = cancellations();
+    let canceled_requests = canceled_requests.fuse();
 
     crate::spawn(
         RequestDispatch {
@@ -220,16 +273,18 @@ where
             transport: transport.fuse(),
             in_flight_requests: FnvHashMap::default(),
             pending_requests: pending_requests.fuse(),
-        }.unwrap_or_else(move |e| error!("[{}] Connection broken: {}", server_addr, e))
-    ).map_err(|e| {
-                io::Error::new(
-                    io::ErrorKind::Other,
-                    format!(
-                        "Could not spawn client dispatch task. Is shutdown: {}",
-                        e.is_shutdown()
-                    ),
-                )
-            })?;
+        }
+        .unwrap_or_else(move |e| error!("[{}] Connection broken: {}", server_addr, e)),
+    )
+    .map_err(|e| {
+        io::Error::new(
+            io::ErrorKind::Other,
+            format!(
+                "Could not spawn client dispatch task. Is shutdown: {}",
+                e.is_shutdown()
+            ),
+        )
+    })?;
 
     Ok(Channel {
         to_dispatch,
@@ -247,7 +302,7 @@ struct RequestDispatch<Req, Resp, C> {
     /// Requests waiting to be written to the wire.
     pending_requests: Fuse<mpsc::Receiver<DispatchRequest<Req, Resp>>>,
     /// Requests that were dropped.
-    canceled_requests: CanceledRequests,
+    canceled_requests: Fuse<CanceledRequests>,
     /// Requests already written to the wire that haven't yet received responses.
     in_flight_requests: FnvHashMap<u64, InFlightData<Resp>>,
     /// Configures limits to prevent unlimited resource usage.
@@ -258,36 +313,36 @@ struct RequestDispatch<Req, Resp, C> {
 
 impl<Req, Resp, C> RequestDispatch<Req, Resp, C>
 where
-    Req: Send,
-    Resp: Send,
+    Req: marker::Send,
+    Resp: marker::Send,
     C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>>,
 {
     unsafe_pinned!(server_addr: SocketAddr);
     unsafe_pinned!(in_flight_requests: FnvHashMap<u64, InFlightData<Resp>>);
-    unsafe_pinned!(canceled_requests: CanceledRequests);
+    unsafe_pinned!(canceled_requests: Fuse<CanceledRequests>);
     unsafe_pinned!(pending_requests: Fuse<mpsc::Receiver<DispatchRequest<Req, Resp>>>);
     unsafe_pinned!(transport: Fuse<C>);
 
-    fn pump_read(self: &mut Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<io::Result<()>>> {
-        Poll::Ready(match ready!(self.transport().poll_next(waker)?) {
+    fn pump_read(self: &mut Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<()> {
+        Poll::Ready(match ready!(self.as_mut().transport().poll_next(cx)?) {
             Some(response) => {
                 self.complete(response);
                 Some(Ok(()))
             }
             None => {
-                trace!("[{}] read half closed", self.server_addr());
+                trace!("[{}] read half closed", self.as_mut().server_addr());
                 None
             }
         })
     }
 
-    fn pump_write(self: &mut Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<io::Result<()>>> {
+    fn pump_write(self: &mut Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<()> {
         enum ReceiverStatus {
             NotReady,
             Closed,
         }
 
-        let pending_requests_status = match self.poll_next_request(waker)? {
+        let pending_requests_status = match self.poll_next_request(cx)? {
             Poll::Ready(Some(dispatch_request)) => {
                 self.write_request(dispatch_request)?;
                 return Poll::Ready(Some(Ok(())));
@@ -296,7 +351,7 @@ where
             Poll::Pending => ReceiverStatus::NotReady,
         };
 
-        let canceled_requests_status = match self.poll_next_cancellation(waker)? {
+        let canceled_requests_status = match self.poll_next_cancellation(cx)? {
             Poll::Ready(Some((context, request_id))) => {
                 self.write_cancel(context, request_id)?;
                 return Poll::Ready(Some(Ok(())));
@@ -307,12 +362,12 @@ where
 
         match (pending_requests_status, canceled_requests_status) {
             (ReceiverStatus::Closed, ReceiverStatus::Closed) => {
-                ready!(self.transport().poll_flush(waker)?);
+                ready!(self.as_mut().transport().poll_flush(cx)?);
                 Poll::Ready(None)
             }
             (ReceiverStatus::NotReady, _) | (_, ReceiverStatus::NotReady) => {
                 // No more messages to process, so flush any messages buffered in the transport.
-                ready!(self.transport().poll_flush(waker)?);
+                ready!(self.as_mut().transport().poll_flush(cx)?);
 
                 // Even if we fully-flush, we return Pending, because we have no more requests
                 // or cancellations right now.
@@ -324,12 +379,12 @@ where
     /// Yields the next pending request, if one is ready to be sent.
     fn poll_next_request(
         self: &mut Pin<&mut Self>,
-        waker: &LocalWaker,
-    ) -> Poll<Option<io::Result<DispatchRequest<Req, Resp>>>> {
-        if self.in_flight_requests().len() >= self.config.max_in_flight_requests {
+        cx: &mut Context<'_>,
+    ) -> PollIo<DispatchRequest<Req, Resp>> {
+        if self.as_mut().in_flight_requests().len() >= self.config.max_in_flight_requests {
             info!(
                 "At in-flight request capacity ({}/{}).",
-                self.in_flight_requests().len(),
+                self.as_mut().in_flight_requests().len(),
                 self.config.max_in_flight_requests
             );
 
@@ -338,13 +393,13 @@ where
             return Poll::Pending;
         }
 
-        while let Poll::Pending = self.transport().poll_ready(waker)? {
+        while let Poll::Pending = self.as_mut().transport().poll_ready(cx)? {
             // We can't yield a request-to-be-sent before the transport is capable of buffering it.
-            ready!(self.transport().poll_flush(waker)?);
+            ready!(self.as_mut().transport().poll_flush(cx)?);
         }
 
         loop {
-            match ready!(self.pending_requests().poll_next_unpin(waker)) {
+            match ready!(self.as_mut().pending_requests().poll_next_unpin(cx)) {
                 Some(request) => {
                     if request.response_completion.is_canceled() {
                         trace!(
@@ -357,7 +412,7 @@ where
                     return Poll::Ready(Some(Ok(request)));
                 }
                 None => {
-                    trace!("[{}] pending_requests closed", self.server_addr());
+                    trace!("[{}] pending_requests closed", self.as_mut().server_addr());
                     return Poll::Ready(None);
                 }
             }
@@ -367,29 +422,35 @@ where
     /// Yields the next pending cancellation, and, if one is ready, cancels the associated request.
     fn poll_next_cancellation(
         self: &mut Pin<&mut Self>,
-        waker: &LocalWaker,
-    ) -> Poll<Option<io::Result<(context::Context, u64)>>> {
-        while let Poll::Pending = self.transport().poll_ready(waker)? {
-            ready!(self.transport().poll_flush(waker)?);
+        cx: &mut Context<'_>,
+    ) -> PollIo<(context::Context, u64)> {
+        while let Poll::Pending = self.as_mut().transport().poll_ready(cx)? {
+            ready!(self.as_mut().transport().poll_flush(cx)?);
         }
 
         loop {
-            match ready!(self.canceled_requests().poll_next_unpin(waker)) {
+            let cancellation = self.as_mut().canceled_requests().poll_next_unpin(cx);
+            match ready!(cancellation) {
                 Some(request_id) => {
-                    if let Some(in_flight_data) = self.in_flight_requests().remove(&request_id) {
-                        self.in_flight_requests().compact(0.1);
+                    if let Some(in_flight_data) =
+                        self.as_mut().in_flight_requests().remove(&request_id)
+                    {
+                        self.as_mut().in_flight_requests().compact(0.1);
 
                         debug!(
                             "[{}/{}] Removed request.",
                             in_flight_data.ctx.trace_id(),
-                            self.server_addr()
+                            self.as_mut().server_addr()
                         );
 
                         return Poll::Ready(Some(Ok((in_flight_data.ctx, request_id))));
                     }
                 }
                 None => {
-                    trace!("[{}] canceled_requests closed.", self.server_addr());
+                    trace!(
+                        "[{}] canceled_requests closed.",
+                        self.as_mut().server_addr()
+                    );
                     return Poll::Ready(None);
                 }
             }
@@ -409,8 +470,8 @@ where
                 deadline: dispatch_request.ctx.deadline,
             }),
         };
-        self.transport().start_send(request)?;
-        self.in_flight_requests().insert(
+        self.as_mut().transport().start_send(request)?;
+        self.as_mut().in_flight_requests().insert(
             request_id,
             InFlightData {
                 ctx: dispatch_request.ctx,
@@ -430,20 +491,28 @@ where
             trace_context: context.trace_context,
             message: ClientMessageKind::Cancel { request_id },
         };
-        self.transport().start_send(cancel)?;
-        trace!("[{}/{}] Cancel message sent.", trace_id, self.server_addr());
-        return Ok(());
+        self.as_mut().transport().start_send(cancel)?;
+        trace!(
+            "[{}/{}] Cancel message sent.",
+            trace_id,
+            self.as_mut().server_addr()
+        );
+        Ok(())
     }
 
     /// Sends a server response to the client task that initiated the associated request.
     fn complete(self: &mut Pin<&mut Self>, response: Response<Resp>) -> bool {
-        if let Some(in_flight_data) = self.in_flight_requests().remove(&response.request_id) {
-            self.in_flight_requests().compact(0.1);
+        if let Some(in_flight_data) = self
+            .as_mut()
+            .in_flight_requests()
+            .remove(&response.request_id)
+        {
+            self.as_mut().in_flight_requests().compact(0.1);
 
             trace!(
                 "[{}/{}] Received response.",
                 in_flight_data.ctx.trace_id(),
-                self.server_addr()
+                self.as_mut().server_addr()
             );
             let _ = in_flight_data.response_completion.send(response);
             return true;
@@ -451,7 +520,7 @@ where
 
         debug!(
             "[{}] No in-flight request found for request_id = {}.",
-            self.server_addr(),
+            self.as_mut().server_addr(),
             response.request_id
         );
 
@@ -462,21 +531,21 @@ where
 
 impl<Req, Resp, C> Future for RequestDispatch<Req, Resp, C>
 where
-    Req: Send,
-    Resp: Send,
+    Req: marker::Send,
+    Resp: marker::Send,
     C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>>,
 {
     type Output = io::Result<()>;
 
-    fn poll(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
-        trace!("[{}] RequestDispatch::poll", self.server_addr());
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        trace!("[{}] RequestDispatch::poll", self.as_mut().server_addr());
         loop {
-            match (self.pump_read(waker)?, self.pump_write(waker)?) {
+            match (self.pump_read(cx)?, self.pump_write(cx)?) {
                 (read, write @ Poll::Ready(None)) => {
-                    if self.in_flight_requests().is_empty() {
+                    if self.as_mut().in_flight_requests().is_empty() {
                         info!(
                             "[{}] Shutdown: write half closed, and no requests in flight.",
-                            self.server_addr()
+                            self.as_mut().server_addr()
                         );
                         return Poll::Ready(Ok(()));
                     }
@@ -485,7 +554,7 @@ where
                         _ => {
                             trace!(
                                 "[{}] read: {:?}, write: {:?}, (not ready)",
-                                self.server_addr(),
+                                self.as_mut().server_addr(),
                                 read,
                                 write,
                             );
@@ -496,7 +565,7 @@ where
                 (read @ Poll::Ready(Some(())), write) | (read, write @ Poll::Ready(Some(()))) => {
                     trace!(
                         "[{}] read: {:?}, write: {:?}",
-                        self.server_addr(),
+                        self.as_mut().server_addr(),
                         read,
                         write,
                     )
@@ -504,7 +573,7 @@ where
                 (read, write) => {
                     trace!(
                         "[{}] read: {:?}, write: {:?} (not ready)",
-                        self.server_addr(),
+                        self.as_mut().server_addr(),
                         read,
                         write,
                     );
@@ -558,14 +627,200 @@ impl RequestCancellation {
 impl Stream for CanceledRequests {
     type Item = u64;
 
-    fn poll_next(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<u64>> {
-        self.0.poll_next_unpin(waker)
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<u64>> {
+        self.0.poll_next_unpin(cx)
+    }
+}
+
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct MapErrConnectionReset<Fut> {
+    future: Fut,
+    finished: Option<()>,
+}
+
+impl<Fut> MapErrConnectionReset<Fut> {
+    unsafe_pinned!(future: Fut);
+    unsafe_unpinned!(finished: Option<()>);
+
+    fn new(future: Fut) -> MapErrConnectionReset<Fut> {
+        MapErrConnectionReset {
+            future,
+            finished: Some(()),
+        }
+    }
+}
+
+impl<Fut: Unpin> Unpin for MapErrConnectionReset<Fut> {}
+
+impl<Fut> Future for MapErrConnectionReset<Fut>
+where
+    Fut: TryFuture,
+{
+    type Output = io::Result<Fut::Ok>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        match self.as_mut().future().try_poll(cx) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(result) => {
+                self.finished().take().expect(
+                    "MapErrConnectionReset must not be polled after it returned `Poll::Ready`",
+                );
+                Poll::Ready(result.map_err(|_| io::Error::from(io::ErrorKind::ConnectionReset)))
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct MapOkDispatchResponse<Fut, Resp> {
+    future: Fut,
+    response: Option<DispatchResponse<Resp>>,
+}
+
+impl<Fut, Resp> MapOkDispatchResponse<Fut, Resp> {
+    unsafe_pinned!(future: Fut);
+    unsafe_unpinned!(response: Option<DispatchResponse<Resp>>);
+
+    fn new(future: Fut, response: DispatchResponse<Resp>) -> MapOkDispatchResponse<Fut, Resp> {
+        MapOkDispatchResponse {
+            future,
+            response: Some(response),
+        }
+    }
+}
+
+impl<Fut: Unpin, Resp> Unpin for MapOkDispatchResponse<Fut, Resp> {}
+
+impl<Fut, Resp> Future for MapOkDispatchResponse<Fut, Resp>
+where
+    Fut: TryFuture,
+{
+    type Output = Result<DispatchResponse<Resp>, Fut::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        match self.as_mut().future().try_poll(cx) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(result) => {
+                let response = self
+                    .as_mut()
+                    .response()
+                    .take()
+                    .expect("MapOk must not be polled after it returned `Poll::Ready`");
+                Poll::Ready(result.map(|_| response))
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct AndThenIdent<Fut1, Fut2> {
+    try_chain: TryChain<Fut1, Fut2>,
+}
+
+impl<Fut1, Fut2> AndThenIdent<Fut1, Fut2>
+where
+    Fut1: TryFuture<Ok = Fut2>,
+    Fut2: TryFuture,
+{
+    unsafe_pinned!(try_chain: TryChain<Fut1, Fut2>);
+
+    /// Creates a new `Then`.
+    fn new(future: Fut1) -> AndThenIdent<Fut1, Fut2> {
+        AndThenIdent {
+            try_chain: TryChain::new(future),
+        }
+    }
+}
+
+impl<Fut1, Fut2> Future for AndThenIdent<Fut1, Fut2>
+where
+    Fut1: TryFuture<Ok = Fut2>,
+    Fut2: TryFuture<Error = Fut1::Error>,
+{
+    type Output = Result<Fut2::Ok, Fut2::Error>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        self.try_chain().poll(cx, |result| match result {
+            Ok(ok) => TryChainAction::Future(ok),
+            Err(err) => TryChainAction::Output(Err(err)),
+        })
+    }
+}
+
+#[must_use = "futures do nothing unless polled"]
+#[derive(Debug)]
+enum TryChain<Fut1, Fut2> {
+    First(Fut1),
+    Second(Fut2),
+    Empty,
+}
+
+enum TryChainAction<Fut2>
+where
+    Fut2: TryFuture,
+{
+    Future(Fut2),
+    Output(Result<Fut2::Ok, Fut2::Error>),
+}
+
+impl<Fut1, Fut2> TryChain<Fut1, Fut2>
+where
+    Fut1: TryFuture<Ok = Fut2>,
+    Fut2: TryFuture,
+{
+    fn new(fut1: Fut1) -> TryChain<Fut1, Fut2> {
+        TryChain::First(fut1)
+    }
+
+    fn poll<F>(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        f: F,
+    ) -> Poll<Result<Fut2::Ok, Fut2::Error>>
+    where
+        F: FnOnce(Result<Fut1::Ok, Fut1::Error>) -> TryChainAction<Fut2>,
+    {
+        let mut f = Some(f);
+
+        // Safe to call `get_unchecked_mut` because we won't move the futures.
+        let this = unsafe { Pin::get_unchecked_mut(self) };
+
+        loop {
+            let output = match this {
+                TryChain::First(fut1) => {
+                    // Poll the first future
+                    match unsafe { Pin::new_unchecked(fut1) }.try_poll(cx) {
+                        Poll::Pending => return Poll::Pending,
+                        Poll::Ready(output) => output,
+                    }
+                }
+                TryChain::Second(fut2) => {
+                    // Poll the second future
+                    return unsafe { Pin::new_unchecked(fut2) }.try_poll(cx);
+                }
+                TryChain::Empty => {
+                    panic!("future must not be polled after it returned `Poll::Ready`");
+                }
+            };
+
+            *this = TryChain::Empty; // Drop fut1
+            let f = f.take().unwrap();
+            match f(output) {
+                TryChainAction::Future(fut2) => *this = TryChain::Second(fut2),
+                TryChainAction::Output(output) => return Poll::Ready(output),
+            }
+        }
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use super::{CanceledRequests, Channel, RequestCancellation, RequestDispatch};
+    use super::{
+        CanceledRequests, Channel, DispatchResponse, RequestCancellation, RequestDispatch,
+    };
     use crate::{
         client::Config,
         context,
@@ -573,9 +828,10 @@ mod tests {
         ClientMessage, Response,
     };
     use fnv::FnvHashMap;
-    use futures::{Poll, channel::mpsc, prelude::*};
-    use futures_test::task::{noop_local_waker_ref};
+    use futures::{channel::mpsc, prelude::*, task::Context, Poll};
+    use futures_test::task::noop_waker_ref;
     use std::{
+        marker,
         net::{IpAddr, Ipv4Addr, SocketAddr},
         pin::Pin,
         sync::atomic::AtomicU64,
@@ -585,20 +841,12 @@ mod tests {
     #[test]
     fn stage_request() {
         let (mut dispatch, mut channel, _server_channel) = set_up();
-
-        // Test that a request future dropped before it's processed by dispatch will cause the request
-        // to not be added to the in-flight request map.
-        let _resp = tokio::runtime::current_thread::block_on_all(
-            channel
-                .send(context::current(), "hi".to_string())
-                .boxed()
-                .compat(),
-        );
-
         let mut dispatch = Pin::new(&mut dispatch);
-        let waker = &noop_local_waker_ref();
+        let cx = &mut Context::from_waker(&noop_waker_ref());
 
-        let req = dispatch.poll_next_request(waker).ready();
+        let _resp = send_request(&mut channel, "hi");
+
+        let req = dispatch.poll_next_request(cx).ready();
         assert!(req.is_some());
 
         let req = req.unwrap();
@@ -606,47 +854,77 @@ mod tests {
         assert_eq!(req.request, "hi".to_string());
     }
 
+    // Regression test for  https://github.com/google/tarpc/issues/220
     #[test]
-    fn stage_request_response_future_dropped() {
-        let (mut dispatch, mut channel, _server_channel) = set_up();
+    fn stage_request_channel_dropped_doesnt_panic() {
+        let (mut dispatch, mut channel, mut server_channel) = set_up();
+        let mut dispatch = Pin::new(&mut dispatch);
+        let cx = &mut Context::from_waker(&noop_waker_ref());
 
-        // Test that a request future dropped before it's processed by dispatch will cause the request
-        // to not be added to the in-flight request map.
-        let resp = tokio::runtime::current_thread::block_on_all(
-            channel
-                .send(context::current(), "hi".into())
-                .boxed()
-                .compat(),
-        ).unwrap();
-        drop(resp);
+        let _ = send_request(&mut channel, "hi");
         drop(channel);
 
-        let mut dispatch = Pin::new(&mut dispatch);
-        let waker = &noop_local_waker_ref();
-
-        dispatch.poll_next_cancellation(waker).unwrap();
-        assert!(dispatch.poll_next_request(waker).ready().is_none());
+        assert!(dispatch.as_mut().poll(cx).is_ready());
+        send_response(
+            &mut server_channel,
+            Response {
+                request_id: 0,
+                message: Ok("hello".into()),
+            },
+        );
+        tokio::runtime::current_thread::block_on_all(dispatch.boxed().compat()).unwrap();
     }
 
     #[test]
-    fn stage_request_response_future_closed() {
+    fn stage_request_response_future_dropped_is_canceled_before_sending() {
         let (mut dispatch, mut channel, _server_channel) = set_up();
+        let mut dispatch = Pin::new(&mut dispatch);
+        let cx = &mut Context::from_waker(&noop_waker_ref());
+
+        let _ = send_request(&mut channel, "hi");
+
+        // Drop the channel so polling returns none if no requests are currently ready.
+        drop(channel);
+        // Test that a request future dropped before it's processed by dispatch will cause the request
+        // to not be added to the in-flight request map.
+        assert!(dispatch.poll_next_request(cx).ready().is_none());
+    }
+
+    #[test]
+    fn stage_request_response_future_dropped_is_canceled_after_sending() {
+        let (mut dispatch, mut channel, _server_channel) = set_up();
+        let cx = &mut Context::from_waker(&noop_waker_ref());
+        let mut dispatch = Pin::new(&mut dispatch);
+
+        let req = send_request(&mut channel, "hi");
+
+        assert!(dispatch.as_mut().pump_write(cx).ready().is_some());
+        assert!(!dispatch.as_mut().in_flight_requests().is_empty());
+
+        // Test that a request future dropped after it's processed by dispatch will cause the request
+        // to be removed from the in-flight request map.
+        drop(req);
+        if let Poll::Ready(Some(_)) = dispatch.as_mut().poll_next_cancellation(cx).unwrap() {
+            // ok
+        } else {
+            panic!("Expected request to be cancelled")
+        };
+        assert!(dispatch.in_flight_requests().is_empty());
+    }
+
+    #[test]
+    fn stage_request_response_closed_skipped() {
+        let (mut dispatch, mut channel, _server_channel) = set_up();
+        let mut dispatch = Pin::new(&mut dispatch);
+        let cx = &mut Context::from_waker(&noop_waker_ref());
 
         // Test that a request future that's closed its receiver but not yet canceled its request --
         // i.e. still in `drop fn` -- will cause the request to not be added to the in-flight request
         // map.
-        let resp = tokio::runtime::current_thread::block_on_all(
-            channel
-                .send(context::current(), "hi".into())
-                .boxed()
-                .compat(),
-        ).unwrap();
-        drop(resp);
-        drop(channel);
+        let mut resp = send_request(&mut channel, "hi");
+        resp.response.get_mut().close();
 
-        let mut dispatch = Pin::new(&mut dispatch);
-        let waker = &noop_local_waker_ref();
-        assert!(dispatch.poll_next_request(waker).ready().is_none());
+        assert!(dispatch.poll_next_request(cx).is_pending());
     }
 
     fn set_up() -> (
@@ -663,7 +941,7 @@ mod tests {
         let dispatch = RequestDispatch::<String, String, _> {
             transport: client_channel.fuse(),
             pending_requests: pending_requests.fuse(),
-            canceled_requests: CanceledRequests(canceled_requests),
+            canceled_requests: CanceledRequests(canceled_requests).fuse(),
             in_flight_requests: FnvHashMap::default(),
             config: Config::default(),
             server_addr: SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0),
@@ -680,6 +958,27 @@ mod tests {
         (dispatch, channel, server_channel)
     }
 
+    fn send_request(
+        channel: &mut Channel<String, String>,
+        request: &str,
+    ) -> DispatchResponse<String> {
+        tokio::runtime::current_thread::block_on_all(
+            channel
+                .send(context::current(), request.to_string())
+                .boxed()
+                .compat(),
+        )
+        .unwrap()
+    }
+
+    fn send_response(
+        channel: &mut UnboundedChannel<ClientMessage<String>, Response<String>>,
+        response: Response<String>,
+    ) {
+        tokio::runtime::current_thread::block_on_all(channel.send(response).boxed().compat())
+            .unwrap();
+    }
+
     trait PollTest {
         type T;
         fn unwrap(self) -> Poll<Self::T>;
@@ -688,7 +987,7 @@ mod tests {
 
     impl<T, E> PollTest for Poll<Option<Result<T, E>>>
     where
-        E: ::std::fmt::Display + Send + 'static,
+        E: ::std::fmt::Display + marker::Send + 'static,
     {
         type T = Option<T>;
 
@@ -710,5 +1009,4 @@ mod tests {
             }
         }
     }
-
 }

rpc/src/client/mod.rs

@@ -6,27 +6,103 @@
 
 //! Provides a client that connects to a server and sends multiplexed requests.
 
-use crate::{context::Context, ClientMessage, Response, Transport};
+use crate::{context, ClientMessage, Response, Transport};
+use futures::prelude::*;
 use log::warn;
 use std::{
     io,
     net::{Ipv4Addr, SocketAddr},
 };
 
-mod dispatch;
+/// Provides a [`Client`] backed by a transport.
+pub mod channel;
+pub use self::channel::Channel;
 
 /// Sends multiplexed requests to, and receives responses from, a server.
-#[derive(Debug)]
-pub struct Client<Req, Resp> {
-    /// Channel to send requests to the dispatch task.
-    channel: dispatch::Channel<Req, Resp>,
+pub trait Client<'a, Req> {
+    /// The response type.
+    type Response;
+
+    /// The future response.
+    type Future: Future<Output = io::Result<Self::Response>> + 'a;
+
+    /// Initiates a request, sending it to the dispatch task.
+    ///
+    /// Returns a [`Future`] that resolves to this client and the future response
+    /// once the request is successfully enqueued.
+    ///
+    /// [`Future`]: futures::Future
+    fn call(&'a mut self, ctx: context::Context, request: Req) -> Self::Future;
+
+    /// Returns a Client that applies a post-processing function to the returned response.
+    fn map_response<F, R>(self, f: F) -> MapResponse<Self, F>
+    where
+        F: FnMut(Self::Response) -> R,
+        Self: Sized,
+    {
+        MapResponse { inner: self, f }
+    }
+
+    /// Returns a Client that applies a pre-processing function to the request.
+    fn with_request<F, Req2>(self, f: F) -> WithRequest<Self, F>
+    where
+        F: FnMut(Req2) -> Req,
+        Self: Sized,
+    {
+        WithRequest { inner: self, f }
+    }
 }
 
-impl<Req, Resp> Clone for Client<Req, Resp> {
-    fn clone(&self) -> Self {
-        Client {
-            channel: self.channel.clone(),
-        }
+/// A Client that applies a function to the returned response.
+#[derive(Clone, Debug)]
+pub struct MapResponse<C, F> {
+    inner: C,
+    f: F,
+}
+
+impl<'a, C, F, Req, Resp, Resp2> Client<'a, Req> for MapResponse<C, F>
+where
+    C: Client<'a, Req, Response = Resp>,
+    F: FnMut(Resp) -> Resp2 + 'a,
+{
+    type Response = Resp2;
+    type Future = futures::future::MapOk<<C as Client<'a, Req>>::Future, &'a mut F>;
+
+    fn call(&'a mut self, ctx: context::Context, request: Req) -> Self::Future {
+        self.inner.call(ctx, request).map_ok(&mut self.f)
+    }
+}
+
+/// A Client that applies a pre-processing function to the request.
+#[derive(Clone, Debug)]
+pub struct WithRequest<C, F> {
+    inner: C,
+    f: F,
+}
+
+impl<'a, C, F, Req, Req2, Resp> Client<'a, Req2> for WithRequest<C, F>
+where
+    C: Client<'a, Req, Response = Resp>,
+    F: FnMut(Req2) -> Req,
+{
+    type Response = Resp;
+    type Future = <C as Client<'a, Req>>::Future;
+
+    fn call(&'a mut self, ctx: context::Context, request: Req2) -> Self::Future {
+        self.inner.call(ctx, (self.f)(request))
+    }
+}
+
+impl<'a, Req, Resp> Client<'a, Req> for Channel<Req, Resp>
+where
+    Req: 'a,
+    Resp: 'a,
+{
+    type Response = Resp;
+    type Future = channel::Call<'a, Req, Resp>;
+
+    fn call(&'a mut self, ctx: context::Context, request: Req) -> channel::Call<'a, Req, Resp> {
+        self.call(ctx, request)
     }
 }
 
@@ -53,39 +129,23 @@ impl Default for Config {
     }
 }
 
-impl<Req, Resp> Client<Req, Resp>
+/// Creates a new Client by wrapping a [`Transport`] and spawning a dispatch task
+/// that manages the lifecycle of requests.
+///
+/// Must only be called from on an executor.
+pub async fn new<Req, Resp, T>(config: Config, transport: T) -> io::Result<Channel<Req, Resp>>
 where
-    Req: Send,
-    Resp: Send,
+    Req: Send + 'static,
+    Resp: Send + 'static,
+    T: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>> + Send + 'static,
 {
-    /// Creates a new Client by wrapping a [`Transport`] and spawning a dispatch task
-    /// that manages the lifecycle of requests.
-    ///
-    /// Must only be called from on an executor.
-    pub async fn new<T>(config: Config, transport: T) -> io::Result<Self>
-    where
-        T: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>> + Send,
-    {
-        let server_addr = transport.peer_addr().unwrap_or_else(|e| {
-            warn!(
-                "Setting peer to unspecified because peer could not be determined: {}",
-                e
-            );
-            SocketAddr::new(Ipv4Addr::UNSPECIFIED.into(), 0)
-        });
+    let server_addr = transport.peer_addr().unwrap_or_else(|e| {
+        warn!(
+            "Setting peer to unspecified because peer could not be determined: {}",
+            e
+        );
+        SocketAddr::new(Ipv4Addr::UNSPECIFIED.into(), 0)
+    });
 
-        Ok(Client {
-            channel: await!(dispatch::spawn(config, transport, server_addr))?,
-        })
-    }
-
-    /// Initiates a request, sending it to the dispatch task.
-    ///
-    /// Returns a [`Future`] that resolves to this client and the future response
-    /// once the request is successfully enqueued.
-    ///
-    /// [`Future`]: futures::Future
-    pub async fn call(&mut self, ctx: Context, request: Req) -> io::Result<Resp> {
-        await!(self.channel.call(ctx, request))
-    }
+    Ok(await!(channel::spawn(config, transport, server_addr))?)
 }

rpc/src/lib.rs

@@ -5,21 +5,13 @@
 // https://opensource.org/licenses/MIT.
 
 #![feature(
-    const_fn,
     non_exhaustive,
     integer_atomics,
     try_trait,
-    nll,
     futures_api,
-    pin,
     arbitrary_self_types,
     await_macro,
-    async_await,
-    generators,
-    optin_builtin_traits,
-    generator_trait,
-    gen_future,
-    decl_macro,
+    async_await
 )]
 #![deny(missing_docs, missing_debug_implementations)]
 
@@ -49,15 +41,15 @@ pub(crate) mod util;
 
 pub use crate::{client::Client, server::Server, transport::Transport};
 
-use futures::{Future, task::{Spawn, SpawnExt, SpawnError}};
+use futures::{
+    task::{Poll, Spawn, SpawnError, SpawnExt},
+    Future,
+};
 use std::{cell::RefCell, io, sync::Once, time::SystemTime};
 
 /// A message from a client to a server.
 #[derive(Debug)]
-#[cfg_attr(
-    feature = "serde1",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
 #[non_exhaustive]
 pub struct ClientMessage<T> {
     /// The trace context associates the message with a specific chain of causally-related actions,
@@ -69,10 +61,7 @@ pub struct ClientMessage<T> {
 
 /// Different messages that can be sent from a client to a server.
 #[derive(Debug)]
-#[cfg_attr(
-    feature = "serde1",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
 #[non_exhaustive]
 pub enum ClientMessageKind<T> {
     /// A request initiated by a user. The server responds to a request by invoking a
@@ -94,10 +83,7 @@ pub enum ClientMessageKind<T> {
 
 /// A request from a client to a server.
 #[derive(Debug)]
-#[cfg_attr(
-    feature = "serde1",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
 #[non_exhaustive]
 pub struct Request<T> {
     /// Uniquely identifies the request across all requests sent over a single channel.
@@ -119,10 +105,7 @@ pub struct Request<T> {
 
 /// A response from a server to a client.
 #[derive(Debug, PartialEq, Eq)]
-#[cfg_attr(
-    feature = "serde1",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
 #[non_exhaustive]
 pub struct Response<T> {
     /// The ID of the request being responded to.
@@ -133,10 +116,7 @@ pub struct Response<T> {
 
 /// An error response from a server to a client.
 #[derive(Debug, PartialEq, Eq)]
-#[cfg_attr(
-    feature = "serde1",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
 #[non_exhaustive]
 pub struct ServerError {
     #[cfg_attr(
@@ -166,6 +146,8 @@ impl<T> Request<T> {
     }
 }
 
+pub(crate) type PollIo<T> = Poll<Option<io::Result<T>>>;
+
 static INIT: Once = Once::new();
 static mut SEED_SPAWN: Option<Box<dyn CloneSpawn>> = None;
 thread_local! {
@@ -174,7 +156,7 @@ thread_local! {
             // INIT must always be called before accessing SPAWN.
             // Otherwise, accessing SPAWN can trigger undefined behavior due to race conditions.
             INIT.call_once(|| {});
-            RefCell::new(SEED_SPAWN.clone().expect("init() must be called."))
+            RefCell::new(SEED_SPAWN.as_ref().expect("init() must be called.").box_clone())
         }
     };
 }
@@ -193,21 +175,13 @@ pub fn init(spawn: impl Spawn + Clone + 'static) {
 }
 
 pub(crate) fn spawn(future: impl Future<Output = ()> + Send + 'static) -> Result<(), SpawnError> {
-    SPAWN.with(|spawn| {
-        spawn.borrow_mut().spawn(future)
-    })
+    SPAWN.with(|spawn| spawn.borrow_mut().spawn(future))
 }
 
 trait CloneSpawn: Spawn {
     fn box_clone(&self) -> Box<dyn CloneSpawn>;
 }
 
-impl Clone for Box<dyn CloneSpawn> {
-    fn clone(&self) -> Self {
-        self.box_clone()
-    }
-}
-
 impl<S: Spawn + Clone + 'static> CloneSpawn for S {
     fn box_clone(&self) -> Box<dyn CloneSpawn> {
         Box::new(self.clone())

rpc/src/server/filter.rs

@@ -7,10 +7,16 @@
 use crate::{
     server::{Channel, Config},
     util::Compact,
-    ClientMessage, Response, Transport,
+    ClientMessage, PollIo, Response, Transport,
 };
 use fnv::FnvHashMap;
-use futures::{channel::mpsc, prelude::*, ready, stream::Fuse, task::{LocalWaker, Poll}};
+use futures::{
+    channel::mpsc,
+    prelude::*,
+    ready,
+    stream::Fuse,
+    task::{Context, Poll},
+};
 use log::{debug, error, info, trace, warn};
 use pin_utils::unsafe_pinned;
 use std::{
@@ -101,28 +107,28 @@ impl<S, Req, Resp> ConnectionFilter<S, Req, Resp> {
             }
         };
 
-        let open_connections = *self.open_connections();
-        if open_connections >= self.config().max_connections {
+        let open_connections = *self.as_mut().open_connections();
+        if open_connections >= self.as_mut().config().max_connections {
             warn!(
                 "[{}] Shedding connection because the maximum open connections \
                  limit is reached ({}/{}).",
                 peer,
                 open_connections,
-                self.config().max_connections
+                self.as_mut().config().max_connections
             );
             return NewConnection::Filtered;
         }
 
         let config = self.config.clone();
         let open_connections_for_ip = self.increment_connections_for_ip(&peer)?;
-        *self.open_connections() += 1;
+        *self.as_mut().open_connections() += 1;
 
         debug!(
             "[{}] Opening channel ({}/{} connections for IP, {} total).",
             peer,
             open_connections_for_ip,
             config.max_connections_per_ip,
-            self.open_connections(),
+            self.as_mut().open_connections(),
         );
 
         NewConnection::Accepted(Channel {
@@ -135,19 +141,19 @@ impl<S, Req, Resp> ConnectionFilter<S, Req, Resp> {
     }
 
     fn handle_closed_connection(self: &mut Pin<&mut Self>, addr: &SocketAddr) {
-        *self.open_connections() -= 1;
+        *self.as_mut().open_connections() -= 1;
         debug!(
             "[{}] Closing channel. {} open connections remaining.",
             addr, self.open_connections
         );
         self.decrement_connections_for_ip(&addr);
-        self.connections_per_ip().compact(0.1);
+        self.as_mut().connections_per_ip().compact(0.1);
     }
 
     fn increment_connections_for_ip(self: &mut Pin<&mut Self>, peer: &SocketAddr) -> Option<usize> {
-        let max_connections_per_ip = self.config().max_connections_per_ip;
+        let max_connections_per_ip = self.as_mut().config().max_connections_per_ip;
         let mut occupied;
-        let mut connections_per_ip = self.connections_per_ip();
+        let mut connections_per_ip = self.as_mut().connections_per_ip();
         let occupied = match connections_per_ip.entry(peer.ip()) {
             Entry::Vacant(vacant) => vacant.insert(0),
             Entry::Occupied(o) => {
@@ -171,7 +177,7 @@ impl<S, Req, Resp> ConnectionFilter<S, Req, Resp> {
     }
 
     fn decrement_connections_for_ip(self: &mut Pin<&mut Self>, addr: &SocketAddr) {
-        let should_compact = match self.connections_per_ip().entry(addr.ip()) {
+        let should_compact = match self.as_mut().connections_per_ip().entry(addr.ip()) {
             Entry::Vacant(_) => {
                 error!("[{}] Got vacant entry when closing connection.", addr);
                 return;
@@ -187,19 +193,19 @@ impl<S, Req, Resp> ConnectionFilter<S, Req, Resp> {
             }
         };
         if should_compact {
-            self.connections_per_ip().compact(0.1);
+            self.as_mut().connections_per_ip().compact(0.1);
         }
     }
 
     fn poll_listener<C>(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
-    ) -> Poll<Option<io::Result<NewConnection<Req, Resp, C>>>>
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> PollIo<NewConnection<Req, Resp, C>>
     where
         S: Stream<Item = Result<C, io::Error>>,
         C: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
     {
-        match ready!(self.listener().poll_next_unpin(cx)?) {
+        match ready!(self.as_mut().listener().poll_next_unpin(cx)?) {
             Some(codec) => Poll::Ready(Some(Ok(self.handle_new_connection(codec)))),
             None => Poll::Ready(None),
         }
@@ -207,9 +213,9 @@ impl<S, Req, Resp> ConnectionFilter<S, Req, Resp> {
 
     fn poll_closed_connections(
         self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
+        cx: &mut Context<'_>,
     ) -> Poll<io::Result<()>> {
-        match ready!(self.closed_connections_rx().poll_next_unpin(cx)) {
+        match ready!(self.as_mut().closed_connections_rx().poll_next_unpin(cx)) {
             Some(addr) => {
                 self.handle_closed_connection(&addr);
                 Poll::Ready(Ok(()))
@@ -226,25 +232,28 @@ where
 {
     type Item = io::Result<Channel<Req, Resp, T>>;
 
-    fn poll_next(
-        mut self: Pin<&mut Self>,
-        cx: &LocalWaker,
-    ) -> Poll<Option<io::Result<Channel<Req, Resp, T>>>> {
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<Channel<Req, Resp, T>> {
         loop {
-            match (self.poll_listener(cx)?, self.poll_closed_connections(cx)?) {
+            match (
+                self.as_mut().poll_listener(cx)?,
+                self.poll_closed_connections(cx)?,
+            ) {
                 (Poll::Ready(Some(NewConnection::Accepted(channel))), _) => {
-                    return Poll::Ready(Some(Ok(channel)))
+                    return Poll::Ready(Some(Ok(channel)));
                 }
                 (Poll::Ready(Some(NewConnection::Filtered)), _) | (_, Poll::Ready(())) => {
-                    trace!("Filtered a connection; {} open.", self.open_connections());
+                    trace!(
+                        "Filtered a connection; {} open.",
+                        self.as_mut().open_connections()
+                    );
                     continue;
                 }
                 (Poll::Pending, Poll::Pending) => return Poll::Pending,
                 (Poll::Ready(None), Poll::Pending) => {
-                    if *self.open_connections() > 0 {
+                    if *self.as_mut().open_connections() > 0 {
                         trace!(
                             "Listener closed; {} open connections.",
-                            self.open_connections()
+                            self.as_mut().open_connections()
                         );
                         return Poll::Pending;
                     }

rpc/src/server/mod.rs

@@ -7,8 +7,8 @@
 //! Provides a server that concurrently handles many connections sending multiplexed requests.
 
 use crate::{
-    context::Context, util::deadline_compat, util::AsDuration, util::Compact, ClientMessage,
-    ClientMessageKind, Request, Response, ServerError, Transport,
+    context, util::deadline_compat, util::AsDuration, util::Compact, ClientMessage,
+    ClientMessageKind, PollIo, Request, Response, ServerError, Transport,
 };
 use fnv::FnvHashMap;
 use futures::{
@@ -17,7 +17,7 @@ use futures::{
     prelude::*,
     ready,
     stream::Fuse,
-    task::{LocalWaker, Poll},
+    task::{Context, Poll},
     try_ready,
 };
 use humantime::format_rfc3339;
@@ -43,6 +43,12 @@ pub struct Server<Req, Resp> {
     ghost: PhantomData<(Req, Resp)>,
 }
 
+impl<Req, Resp> Default for Server<Req, Resp> {
+    fn default() -> Self {
+        new(Config::default())
+    }
+}
+
 /// Settings that control the behavior of the server.
 #[non_exhaustive]
 #[derive(Clone, Debug)]
@@ -75,15 +81,15 @@ impl Default for Config {
     }
 }
 
-impl<Req, Resp> Server<Req, Resp> {
-    /// Returns a new server with configuration specified `config`.
-    pub fn new(config: Config) -> Self {
-        Server {
-            config,
-            ghost: PhantomData,
-        }
+/// Returns a new server with configuration specified `config`.
+pub fn new<Req, Resp>(config: Config) -> Server<Req, Resp> {
+    Server {
+        config,
+        ghost: PhantomData,
     }
+}
 
+impl<Req, Resp> Server<Req, Resp> {
     /// Returns the config for this server.
     pub fn config(&self) -> &Config {
         &self.config
@@ -122,17 +128,18 @@ where
     Req: Send + 'static,
     Resp: Send + 'static,
     T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send + 'static,
-    F: FnMut(Context, Req) -> Fut + Send + 'static + Clone,
+    F: FnOnce(context::Context, Req) -> Fut + Send + 'static + Clone,
     Fut: Future<Output = io::Result<Resp>> + Send + 'static,
 {
     type Output = ();
 
-    fn poll(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<()> {
-        while let Some(channel) = ready!(self.incoming().poll_next(cx)) {
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
+        while let Some(channel) = ready!(self.as_mut().incoming().poll_next(cx)) {
             match channel {
                 Ok(channel) => {
                     let peer = channel.client_addr;
-                    if let Err(e) = crate::spawn(channel.respond_with(self.request_handler().clone()))
+                    if let Err(e) =
+                        crate::spawn(channel.respond_with(self.as_mut().request_handler().clone()))
                     {
                         warn!("[{}] Failed to spawn connection handler: {:?}", peer, e);
                     }
@@ -143,7 +150,7 @@ where
             }
         }
         info!("Server shutting down.");
-        return Poll::Ready(());
+        Poll::Ready(())
     }
 }
 
@@ -158,7 +165,7 @@ where
     /// Responds to all requests with `request_handler`.
     fn respond_with<F, Fut>(self, request_handler: F) -> Running<Self, F>
     where
-        F: FnMut(Context, Req) -> Fut + Send + 'static + Clone,
+        F: FnOnce(context::Context, Req) -> Fut + Send + 'static + Clone,
         Fut: Future<Output = io::Result<Resp>> + Send + 'static,
     {
         Running {
@@ -174,7 +181,8 @@ where
     Req: Send,
     Resp: Send,
     T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
-{}
+{
+}
 
 /// Responds to all requests with `request_handler`.
 /// The server end of an open connection with a client.
@@ -222,29 +230,29 @@ where
     Req: Send,
     Resp: Send,
 {
-    pub(crate) fn start_send(self: &mut Pin<&mut Self>, response: Response<Resp>) -> io::Result<()> {
-        self.transport().start_send(response)
+    pub(crate) fn start_send(mut self: Pin<&mut Self>, response: Response<Resp>) -> io::Result<()> {
+        self.as_mut().transport().start_send(response)
     }
 
     pub(crate) fn poll_ready(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
     ) -> Poll<io::Result<()>> {
-        self.transport().poll_ready(cx)
+        self.as_mut().transport().poll_ready(cx)
     }
 
     pub(crate) fn poll_flush(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
     ) -> Poll<io::Result<()>> {
-        self.transport().poll_flush(cx)
+        self.as_mut().transport().poll_flush(cx)
     }
 
     pub(crate) fn poll_next(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
-    ) -> Poll<Option<io::Result<ClientMessage<Req>>>> {
-        self.transport().poll_next(cx)
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> PollIo<ClientMessage<Req>> {
+        self.as_mut().transport().poll_next(cx)
     }
 
     /// Returns the address of the client connected to the channel.
@@ -256,7 +264,7 @@ where
     /// responses and resolves when the connection is closed.
     pub fn respond_with<F, Fut>(self, f: F) -> impl Future<Output = ()>
     where
-        F: FnMut(Context, Req) -> Fut + Send + 'static,
+        F: FnOnce(context::Context, Req) -> Fut + Send + 'static + Clone,
         Fut: Future<Output = io::Result<Resp>> + Send + 'static,
         Req: 'static,
         Resp: 'static,
@@ -271,7 +279,8 @@ where
             pending_responses: responses,
             responses_tx,
             in_flight_requests: FnvHashMap::default(),
-        }.unwrap_or_else(move |e| {
+        }
+        .unwrap_or_else(move |e| {
             info!("[{}] ClientHandler errored out: {}", peer, e);
         })
     }
@@ -281,9 +290,9 @@ where
 struct ClientHandler<Req, Resp, T, F> {
     channel: Channel<Req, Resp, T>,
     /// Responses waiting to be written to the wire.
-    pending_responses: Fuse<mpsc::Receiver<(Context, Response<Resp>)>>,
+    pending_responses: Fuse<mpsc::Receiver<(context::Context, Response<Resp>)>>,
     /// Handed out to request handlers to fan in responses.
-    responses_tx: mpsc::Sender<(Context, Response<Resp>)>,
+    responses_tx: mpsc::Sender<(context::Context, Response<Resp>)>,
     /// Number of requests currently being responded to.
     in_flight_requests: FnvHashMap<u64, AbortHandle>,
     /// Request handler.
@@ -293,8 +302,8 @@ struct ClientHandler<Req, Resp, T, F> {
 impl<Req, Resp, T, F> ClientHandler<Req, Resp, T, F> {
     unsafe_pinned!(channel: Channel<Req, Resp, T>);
     unsafe_pinned!(in_flight_requests: FnvHashMap<u64, AbortHandle>);
-    unsafe_pinned!(pending_responses: Fuse<mpsc::Receiver<(Context, Response<Resp>)>>);
-    unsafe_pinned!(responses_tx: mpsc::Sender<(Context, Response<Resp>)>);
+    unsafe_pinned!(pending_responses: Fuse<mpsc::Receiver<(context::Context, Response<Resp>)>>);
+    unsafe_pinned!(responses_tx: mpsc::Sender<(context::Context, Response<Resp>)>);
     // For this to be safe, field f must be private, and code in this module must never
     // construct PinMut<F>.
     unsafe_unpinned!(f: F);
@@ -305,36 +314,36 @@ where
     Req: Send + 'static,
     Resp: Send + 'static,
     T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
-    F: FnMut(Context, Req) -> Fut + Send + 'static,
+    F: FnOnce(context::Context, Req) -> Fut + Send + 'static + Clone,
     Fut: Future<Output = io::Result<Resp>> + Send + 'static,
 {
     /// If at max in-flight requests, check that there's room to immediately write a throttled
     /// response.
     fn poll_ready_if_throttling(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
     ) -> Poll<io::Result<()>> {
         if self.in_flight_requests.len()
             >= self.channel.config.max_in_flight_requests_per_connection
         {
-            let peer = self.channel().client_addr;
+            let peer = self.as_mut().channel().client_addr;
 
-            while let Poll::Pending = self.channel().poll_ready(cx)? {
+            while let Poll::Pending = self.as_mut().channel().poll_ready(cx)? {
                 info!(
                     "[{}] In-flight requests at max ({}), and transport is not ready.",
                     peer,
-                    self.in_flight_requests().len(),
+                    self.as_mut().in_flight_requests().len(),
                 );
-                try_ready!(self.channel().poll_flush(cx));
+                try_ready!(self.as_mut().channel().poll_flush(cx));
             }
         }
         Poll::Ready(Ok(()))
     }
 
-    fn pump_read(self: &mut Pin<&mut Self>, cx: &LocalWaker) -> Poll<Option<io::Result<()>>> {
-        ready!(self.poll_ready_if_throttling(cx)?);
+    fn pump_read(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<()> {
+        ready!(self.as_mut().poll_ready_if_throttling(cx)?);
 
-        Poll::Ready(match ready!(self.channel().poll_next(cx)?) {
+        Poll::Ready(match ready!(self.as_mut().channel().poll_next(cx)?) {
             Some(message) => {
                 match message.message {
                     ClientMessageKind::Request(request) => {
@@ -354,28 +363,28 @@ where
     }
 
     fn pump_write(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
         read_half_closed: bool,
-    ) -> Poll<Option<io::Result<()>>> {
-        match self.poll_next_response(cx)? {
+    ) -> PollIo<()> {
+        match self.as_mut().poll_next_response(cx)? {
             Poll::Ready(Some((_, response))) => {
-                self.channel().start_send(response)?;
+                self.as_mut().channel().start_send(response)?;
                 Poll::Ready(Some(Ok(())))
             }
             Poll::Ready(None) => {
                 // Shutdown can't be done before we finish pumping out remaining responses.
-                ready!(self.channel().poll_flush(cx)?);
+                ready!(self.as_mut().channel().poll_flush(cx)?);
                 Poll::Ready(None)
             }
             Poll::Pending => {
                 // No more requests to process, so flush any requests buffered in the transport.
-                ready!(self.channel().poll_flush(cx)?);
+                ready!(self.as_mut().channel().poll_flush(cx)?);
 
                 // Being here means there are no staged requests and all written responses are
                 // fully flushed. So, if the read half is closed and there are no in-flight
                 // requests, then we can close the write half.
-                if read_half_closed && self.in_flight_requests().is_empty() {
+                if read_half_closed && self.as_mut().in_flight_requests().is_empty() {
                     Poll::Ready(None)
                 } else {
                     Poll::Pending
@@ -385,28 +394,33 @@ where
     }
 
     fn poll_next_response(
-        self: &mut Pin<&mut Self>,
-        cx: &LocalWaker,
-    ) -> Poll<Option<io::Result<(Context, Response<Resp>)>>> {
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> PollIo<(context::Context, Response<Resp>)> {
         // Ensure there's room to write a response.
-        while let Poll::Pending = self.channel().poll_ready(cx)? {
-            ready!(self.channel().poll_flush(cx)?);
+        while let Poll::Pending = self.as_mut().channel().poll_ready(cx)? {
+            ready!(self.as_mut().channel().poll_flush(cx)?);
         }
 
-        let peer = self.channel().client_addr;
+        let peer = self.as_mut().channel().client_addr;
 
-        match ready!(self.pending_responses().poll_next(cx)) {
+        match ready!(self.as_mut().pending_responses().poll_next(cx)) {
             Some((ctx, response)) => {
-                if let Some(_) = self.in_flight_requests().remove(&response.request_id) {
-                    self.in_flight_requests().compact(0.1);
+                if self
+                    .as_mut()
+                    .in_flight_requests()
+                    .remove(&response.request_id)
+                    .is_some()
+                {
+                    self.as_mut().in_flight_requests().compact(0.1);
                 }
                 trace!(
                     "[{}/{}] Staging response. In-flight requests = {}.",
                     ctx.trace_id(),
                     peer,
-                    self.in_flight_requests().len(),
+                    self.as_mut().in_flight_requests().len(),
                 );
-                return Poll::Ready(Some(Ok((ctx, response))));
+                Poll::Ready(Some(Ok((ctx, response))))
             }
             None => {
                 // This branch likely won't happen, since the ClientHandler is holding a Sender.
@@ -417,30 +431,37 @@ where
     }
 
     fn handle_request(
-        self: &mut Pin<&mut Self>,
+        mut self: Pin<&mut Self>,
         trace_context: trace::Context,
         request: Request<Req>,
     ) -> io::Result<()> {
         let request_id = request.id;
-        let peer = self.channel().client_addr;
-        let ctx = Context {
+        let peer = self.as_mut().channel().client_addr;
+        let ctx = context::Context {
             deadline: request.deadline,
             trace_context,
         };
         let request = request.message;
 
-        if self.in_flight_requests().len()
-            >= self.channel().config.max_in_flight_requests_per_connection
+        if self.as_mut().in_flight_requests().len()
+            >= self
+                .as_mut()
+                .channel()
+                .config
+                .max_in_flight_requests_per_connection
         {
             debug!(
                 "[{}/{}] Client has reached in-flight request limit ({}/{}).",
                 ctx.trace_id(),
                 peer,
-                self.in_flight_requests().len(),
-                self.channel().config.max_in_flight_requests_per_connection
+                self.as_mut().in_flight_requests().len(),
+                self.as_mut()
+                    .channel()
+                    .config
+                    .max_in_flight_requests_per_connection
             );
 
-            self.channel().start_send(Response {
+            self.as_mut().channel().start_send(Response {
                 request_id,
                 message: Err(ServerError {
                     kind: io::ErrorKind::WouldBlock,
@@ -459,10 +480,10 @@ where
             format_rfc3339(deadline),
             timeout,
         );
-        let mut response_tx = self.responses_tx().clone();
+        let mut response_tx = self.as_mut().responses_tx().clone();
 
         let trace_id = *ctx.trace_id();
-        let response = self.f()(ctx.clone(), request);
+        let response = self.as_mut().f().clone()(ctx, request);
         let response = deadline_compat::Deadline::new(response, Instant::now() + timeout).then(
             async move |result| {
                 let response = Response {
@@ -477,28 +498,29 @@ where
             },
         );
         let (abortable_response, abort_handle) = abortable(response);
-        crate::spawn(abortable_response.map(|_| ()))
-            .map_err(|e| {
-                io::Error::new(
-                    io::ErrorKind::Other,
-                    format!(
-                        "Could not spawn response task. Is shutdown: {}",
-                        e.is_shutdown()
-                    ),
-                )
-            })?;
-        self.in_flight_requests().insert(request_id, abort_handle);
+        crate::spawn(abortable_response.map(|_| ())).map_err(|e| {
+            io::Error::new(
+                io::ErrorKind::Other,
+                format!(
+                    "Could not spawn response task. Is shutdown: {}",
+                    e.is_shutdown()
+                ),
+            )
+        })?;
+        self.as_mut()
+            .in_flight_requests()
+            .insert(request_id, abort_handle);
         Ok(())
     }
 
-    fn cancel_request(self: &mut Pin<&mut Self>, trace_context: &trace::Context, request_id: u64) {
+    fn cancel_request(mut self: Pin<&mut Self>, trace_context: &trace::Context, request_id: u64) {
         // It's possible the request was already completed, so it's fine
         // if this is None.
-        if let Some(cancel_handle) = self.in_flight_requests().remove(&request_id) {
-            self.in_flight_requests().compact(0.1);
+        if let Some(cancel_handle) = self.as_mut().in_flight_requests().remove(&request_id) {
+            self.as_mut().in_flight_requests().compact(0.1);
 
             cancel_handle.abort();
-            let remaining = self.in_flight_requests().len();
+            let remaining = self.as_mut().in_flight_requests().len();
             trace!(
                 "[{}/{}] Request canceled. In-flight requests = {}",
                 trace_context.trace_id,
@@ -521,16 +543,19 @@ where
     Req: Send + 'static,
     Resp: Send + 'static,
     T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
-    F: FnMut(Context, Req) -> Fut + Send + 'static,
+    F: FnOnce(context::Context, Req) -> Fut + Send + 'static + Clone,
     Fut: Future<Output = io::Result<Resp>> + Send + 'static,
 {
     type Output = io::Result<()>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
         trace!("[{}] ClientHandler::poll", self.channel.client_addr);
         loop {
-            let read = self.pump_read(cx)?;
-            match (read, self.pump_write(cx, read == Poll::Ready(None))?) {
+            let read = self.as_mut().pump_read(cx)?;
+            match (
+                read,
+                self.as_mut().pump_write(cx, read == Poll::Ready(None))?,
+            ) {
                 (Poll::Ready(None), Poll::Ready(None)) => {
                     info!("[{}] Client disconnected.", self.channel.client_addr);
                     return Poll::Ready(Ok(()));

rpc/src/transport/channel.rs

@@ -6,8 +6,8 @@
 
 //! Transports backed by in-memory channels.
 
-use crate::Transport;
-use futures::{channel::mpsc, task::{LocalWaker}, Poll, Sink, Stream};
+use crate::{PollIo, Transport};
+use futures::{channel::mpsc, task::Context, Poll, Sink, Stream};
 use pin_utils::unsafe_pinned;
 use std::pin::Pin;
 use std::{
@@ -45,37 +45,33 @@ impl<Item, SinkItem> UnboundedChannel<Item, SinkItem> {
 impl<Item, SinkItem> Stream for UnboundedChannel<Item, SinkItem> {
     type Item = Result<Item, io::Error>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<Option<io::Result<Item>>> {
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<Item> {
         self.rx().poll_next(cx).map(|option| option.map(Ok))
     }
 }
 
-impl<Item, SinkItem> Sink for UnboundedChannel<Item, SinkItem> {
-    type SinkItem = SinkItem;
+impl<Item, SinkItem> Sink<SinkItem> for UnboundedChannel<Item, SinkItem> {
     type SinkError = io::Error;
 
-    fn poll_ready(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
         self.tx()
             .poll_ready(cx)
             .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
     }
 
-    fn start_send(mut self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
+    fn start_send(self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
         self.tx()
             .start_send(item)
             .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
     }
 
-    fn poll_flush(
-        mut self: Pin<&mut Self>,
-        cx: &LocalWaker,
-    ) -> Poll<Result<(), Self::SinkError>> {
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::SinkError>> {
         self.tx()
             .poll_flush(cx)
             .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
     }
 
-    fn poll_close(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
         self.tx()
             .poll_close(cx)
             .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
@@ -83,8 +79,8 @@ impl<Item, SinkItem> Sink for UnboundedChannel<Item, SinkItem> {
 }
 
 impl<Item, SinkItem> Transport for UnboundedChannel<Item, SinkItem> {
-    type Item = Item;
     type SinkItem = SinkItem;
+    type Item = Item;
 
     fn peer_addr(&self) -> io::Result<SocketAddr> {
         Ok(SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0))
@@ -97,18 +93,23 @@ impl<Item, SinkItem> Transport for UnboundedChannel<Item, SinkItem> {
 
 #[cfg(test)]
 mod tests {
-    use crate::{client::{self, Client}, context, server::{self, Handler, Server}, transport};
-    use futures::{prelude::*, stream, compat::TokioDefaultSpawner};
+    use crate::{
+        client, context,
+        server::{Handler, Server},
+        transport,
+    };
+    use futures::compat::Executor01CompatExt;
+    use futures::{prelude::*, stream};
     use log::trace;
     use std::io;
 
     #[test]
     fn integration() {
         let _ = env_logger::try_init();
-        crate::init(TokioDefaultSpawner);
+        crate::init(tokio::executor::DefaultExecutor::current().compat());
 
         let (client_channel, server_channel) = transport::channel::unbounded();
-        let server = Server::<String, u64>::new(server::Config::default())
+        let server = Server::<String, u64>::default()
             .incoming(stream::once(future::ready(Ok(server_channel))))
             .respond_with(|_ctx, request| {
                 future::ready(request.parse::<u64>().map_err(|_| {
@@ -120,7 +121,7 @@ mod tests {
             });
 
         let responses = async {
-            let mut client = await!(Client::new(client::Config::default(), client_channel))?;
+            let mut client = await!(client::new(client::Config::default(), client_channel))?;
 
             let response1 = await!(client.call(context::current(), "123".into()));
             let response2 = await!(client.call(context::current(), "abc".into()));
@@ -128,8 +129,11 @@ mod tests {
             Ok::<_, io::Error>((response1, response2))
         };
 
-        let (response1, response2) =
-            run_future(server.join(responses.unwrap_or_else(|e| panic!(e)))).1;
+        let (response1, response2) = run_future(future::join(
+            server,
+            responses.unwrap_or_else(|e| panic!(e)),
+        ))
+        .1;
 
         trace!("response1: {:?}, response2: {:?}", response1, response2);
 

rpc/src/transport/mod.rs

@@ -10,7 +10,13 @@
 //! can be plugged in, using whatever protocol it wants.
 
 use futures::prelude::*;
-use std::{io, net::SocketAddr};
+use std::{
+    io,
+    marker::PhantomData,
+    net::SocketAddr,
+    pin::Pin,
+    task::{Context, Poll},
+};
 
 pub mod channel;
 
@@ -18,7 +24,7 @@ pub mod channel;
 pub trait Transport
 where
     Self: Stream<Item = io::Result<<Self as Transport>::Item>>,
-    Self: Sink<SinkItem = <Self as Transport>::SinkItem, SinkError = io::Error>,
+    Self: Sink<<Self as Transport>::SinkItem, SinkError = io::Error>,
 {
     /// The type read off the transport.
     type Item;
@@ -30,3 +36,88 @@ where
     /// The address of the local half of this transport.
     fn local_addr(&self) -> io::Result<SocketAddr>;
 }
+
+/// Returns a new Transport backed by the given Stream + Sink and connecting addresses.
+pub fn new<S, SinkItem, Item>(
+    inner: S,
+    peer_addr: SocketAddr,
+    local_addr: SocketAddr,
+) -> impl Transport<Item = Item, SinkItem = SinkItem>
+where
+    S: Stream<Item = io::Result<Item>>,
+    S: Sink<SinkItem, SinkError = io::Error>,
+{
+    TransportShim {
+        inner,
+        peer_addr,
+        local_addr,
+        _marker: PhantomData,
+    }
+}
+
+/// A transport created by adding peers to a Stream + Sink.
+#[derive(Debug)]
+struct TransportShim<S, SinkItem> {
+    peer_addr: SocketAddr,
+    local_addr: SocketAddr,
+    inner: S,
+    _marker: PhantomData<SinkItem>,
+}
+
+impl<S, SinkItem> TransportShim<S, SinkItem> {
+    pin_utils::unsafe_pinned!(inner: S);
+}
+
+impl<S, SinkItem> Stream for TransportShim<S, SinkItem>
+where
+    S: Stream,
+{
+    type Item = S::Item;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<S::Item>> {
+        self.inner().poll_next(cx)
+    }
+}
+
+impl<S, Item> Sink<Item> for TransportShim<S, Item>
+where
+    S: Sink<Item>,
+{
+    type SinkError = S::SinkError;
+
+    fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), S::SinkError> {
+        self.inner().start_send(item)
+    }
+
+    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_ready(cx)
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_flush(cx)
+    }
+
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_close(cx)
+    }
+}
+
+impl<S, SinkItem, Item> Transport for TransportShim<S, SinkItem>
+where
+    S: Stream + Sink<SinkItem>,
+    Self: Stream<Item = io::Result<Item>>,
+    Self: Sink<SinkItem, SinkError = io::Error>,
+{
+    type Item = Item;
+    type SinkItem = SinkItem;
+
+    /// The address of the remote peer this transport is in communication with.
+    fn peer_addr(&self) -> io::Result<SocketAddr> {
+        Ok(self.peer_addr)
+    }
+
+    /// The address of the local half of this transport.
+    fn local_addr(&self) -> io::Result<SocketAddr> {
+        Ok(self.local_addr)
+    }
+}

rpc/src/util/deadline_compat.rs

@@ -5,9 +5,10 @@
 // https://opensource.org/licenses/MIT.
 
 use futures::{
-    compat::{Compat01As03, Future01CompatExt},
+    compat::*,
     prelude::*,
-    ready, task::{Poll, LocalWaker},
+    ready,
+    task::{Context, Poll},
 };
 use pin_utils::unsafe_pinned;
 use std::pin::Pin;
@@ -49,16 +50,15 @@ where
 {
     type Output = Result<T::Ok, timeout::Error<T::Error>>;
 
-    fn poll(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Self::Output> {
-
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         // First, try polling the future
-        match self.future().try_poll(waker) {
+        match self.as_mut().future().try_poll(cx) {
             Poll::Ready(Ok(v)) => return Poll::Ready(Ok(v)),
             Poll::Pending => {}
             Poll::Ready(Err(e)) => return Poll::Ready(Err(timeout::Error::inner(e))),
         }
 
-        let delay = self.delay().poll_unpin(waker);
+        let delay = self.delay().poll_unpin(cx);
 
         // Now check the timer
         match ready!(delay) {

rpc/src/util/serde.rs

@@ -31,6 +31,7 @@ where
 }
 
 /// Serializes [`io::ErrorKind`] as a `u32`.
+#[allow(clippy::trivially_copy_pass_by_ref)] // Exact fn signature required by serde derive
 pub fn serialize_io_error_kind_as_u32<S>(
     kind: &io::ErrorKind,
     serializer: S,
@@ -59,7 +60,8 @@ where
         Other => 16,
         UnexpectedEof => 17,
         _ => 16,
-    }.serialize(serializer)
+    }
+    .serialize(serializer)
 }
 
 /// Deserializes [`io::ErrorKind`] from a `u32`.

tarpc/Cargo.toml

@@ -1,8 +1,6 @@
-cargo-features = ["rename-dependency"]
-
 [package]
 name = "tarpc"
-version = "0.13.0"
+version = "0.16.0"
 authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
 edition = "2018"
 license = "MIT"
@@ -21,18 +19,20 @@ serde1 = ["rpc/serde1", "serde", "serde/derive"]
 travis-ci = { repository = "google/tarpc" }
 
 [dependencies]
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
 log = "0.4"
 serde = { optional = true, version = "1.0" }
+rpc = { package = "tarpc-lib", path = "../rpc", version = "0.4" }
 tarpc-plugins = { path = "../plugins", version = "0.5.0" }
-rpc = { package = "tarpc-lib", path = "../rpc", version = "0.1" }
-
-[target.'cfg(not(test))'.dependencies]
-futures-preview = "0.3.0-alpha.8"
 
 [dev-dependencies]
+bincode = "1"
+bytes = { version = "0.4", features = ["serde"] }
 humantime = "1.0"
-futures-preview = { version = "0.3.0-alpha.8", features = ["compat", "tokio-compat"] }
-bincode-transport = { package = "tarpc-bincode-transport", version = "0.1", path = "../bincode-transport" }
-env_logger = "0.5"
+bincode-transport = { package = "tarpc-bincode-transport", version = "0.5", path = "../bincode-transport" }
+env_logger = "0.6"
+libtest = "0.0.1"
 tokio = "0.1"
 tokio-executor = "0.1"
+tokio-tcp = "0.1"
+pin-utils = "0.1.0-alpha.4"

tarpc/README.md

@@ -0,0 +1 @@
+../README.md

tarpc/examples/pubsub.rs

@@ -6,12 +6,11 @@
 
 #![feature(
     arbitrary_self_types,
-    pin,
     futures_api,
     await_macro,
     async_await,
     existential_type,
-    proc_macro_hygiene,
+    proc_macro_hygiene
 )]
 
 use futures::{
@@ -55,7 +54,7 @@ struct Subscriber {
 impl subscriber::Service for Subscriber {
     type ReceiveFut = Ready<()>;
 
-    fn receive(&self, _: context::Context, message: String) -> Self::ReceiveFut {
+    fn receive(self, _: context::Context, message: String) -> Self::ReceiveFut {
         println!("{} received message: {}", self.id, message);
         future::ready(())
     }
@@ -66,13 +65,13 @@ impl Subscriber {
         let incoming = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
         let addr = incoming.local_addr();
         tokio_executor::spawn(
-            Server::new(config)
+            server::new(config)
                 .incoming(incoming)
                 .take(1)
                 .respond_with(subscriber::serve(Subscriber { id }))
                 .unit_error()
                 .boxed()
-                .compat()
+                .compat(),
         );
         Ok(addr)
     }
@@ -94,7 +93,7 @@ impl Publisher {
 impl publisher::Service for Publisher {
     existential type BroadcastFut: Future<Output = ()>;
 
-    fn broadcast(&self, _: context::Context, message: String) -> Self::BroadcastFut {
+    fn broadcast(self, _: context::Context, message: String) -> Self::BroadcastFut {
         async fn broadcast(clients: Arc<Mutex<HashMap<u32, subscriber::Client>>>, message: String) {
             let mut clients = clients.lock().unwrap().clone();
             for client in clients.values_mut() {
@@ -110,7 +109,7 @@ impl publisher::Service for Publisher {
 
     existential type SubscribeFut: Future<Output = Result<(), String>>;
 
-    fn subscribe(&self, _: context::Context, id: u32, addr: SocketAddr) -> Self::SubscribeFut {
+    fn subscribe(self, _: context::Context, id: u32, addr: SocketAddr) -> Self::SubscribeFut {
         async fn subscribe(
             clients: Arc<Mutex<HashMap<u32, subscriber::Client>>>,
             id: u32,
@@ -128,7 +127,7 @@ impl publisher::Service for Publisher {
 
     existential type UnsubscribeFut: Future<Output = ()>;
 
-    fn unsubscribe(&self, _: context::Context, id: u32) -> Self::UnsubscribeFut {
+    fn unsubscribe(self, _: context::Context, id: u32) -> Self::UnsubscribeFut {
         println!("Unsubscribing {}", id);
         let mut clients = self.clients.lock().unwrap();
         if let None = clients.remove(&id) {
@@ -146,13 +145,13 @@ async fn run() -> io::Result<()> {
     let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
     let publisher_addr = transport.local_addr();
     tokio_executor::spawn(
-        Server::new(server::Config::default())
+        Server::default()
             .incoming(transport)
             .take(1)
             .respond_with(publisher::serve(Publisher::new()))
             .unit_error()
             .boxed()
-            .compat()
+            .compat(),
     );
 
     let subscriber1 = await!(Subscriber::listen(0, server::Config::default()))?;
@@ -180,12 +179,6 @@ async fn run() -> io::Result<()> {
 }
 
 fn main() {
-    tokio::run(
-        run()
-            .boxed()
-            .map_err(|e| panic!(e))
-            .boxed()
-            .compat(),
-    );
+    tokio::run(run().boxed().map_err(|e| panic!(e)).boxed().compat());
     thread::sleep(Duration::from_millis(100));
 }

tarpc/examples/readme.rs

@@ -6,20 +6,20 @@
 
 #![feature(
     futures_api,
-    pin,
     arbitrary_self_types,
     await_macro,
     async_await,
-    proc_macro_hygiene,
+    proc_macro_hygiene
 )]
 
 use futures::{
+    compat::Executor01CompatExt,
     future::{self, Ready},
     prelude::*,
 };
 use rpc::{
     client, context,
-    server::{self, Handler, Server},
+    server::{Handler, Server},
 };
 use std::io;
 
@@ -41,7 +41,7 @@ impl Service for HelloServer {
 
     type HelloFut = Ready<String>;
 
-    fn hello(&self, _: context::Context, name: String) -> Self::HelloFut {
+    fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
         future::ready(format!("Hello, {}!", name))
     }
 }
@@ -53,7 +53,7 @@ async fn run() -> io::Result<()> {
     let addr = transport.local_addr();
 
     // The server is configured with the defaults.
-    let server = Server::new(server::Config::default())
+    let server = Server::default()
         // Server can listen on any type that implements the Transport trait.
         .incoming(transport)
         // Close the stream after the client connects
@@ -82,6 +82,8 @@ async fn run() -> io::Result<()> {
 }
 
 fn main() {
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+
     tokio::run(
         run()
             .map_err(|e| eprintln!("Oh no: {}", e))

tarpc/examples/server_calling_server.rs

@@ -7,21 +7,21 @@
 #![feature(
     existential_type,
     arbitrary_self_types,
-    pin,
     futures_api,
     await_macro,
     async_await,
-    proc_macro_hygiene,
+    proc_macro_hygiene
 )]
 
 use crate::{add::Service as AddService, double::Service as DoubleService};
 use futures::{
+    compat::Executor01CompatExt,
     future::{self, Ready},
     prelude::*,
 };
 use rpc::{
     client, context,
-    server::{self, Handler, Server},
+    server::{Handler, Server},
 };
 use std::io;
 
@@ -45,7 +45,7 @@ struct AddServer;
 impl AddService for AddServer {
     type AddFut = Ready<i32>;
 
-    fn add(&self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
+    fn add(self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
         future::ready(x + y)
     }
 }
@@ -58,7 +58,7 @@ struct DoubleServer {
 impl DoubleService for DoubleServer {
     existential type DoubleFut: Future<Output = Result<i32, String>> + Send;
 
-    fn double(&self, _: context::Context, x: i32) -> Self::DoubleFut {
+    fn double(self, _: context::Context, x: i32) -> Self::DoubleFut {
         async fn double(mut client: add::Client, x: i32) -> Result<i32, String> {
             let result = await!(client.add(context::current(), x, x));
             result.map_err(|e| e.to_string())
@@ -71,7 +71,7 @@ impl DoubleService for DoubleServer {
 async fn run() -> io::Result<()> {
     let add_listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
     let addr = add_listener.local_addr();
-    let add_server = Server::new(server::Config::default())
+    let add_server = Server::default()
         .incoming(add_listener)
         .take(1)
         .respond_with(add::serve(AddServer));
@@ -82,7 +82,7 @@ async fn run() -> io::Result<()> {
 
     let double_listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
     let addr = double_listener.local_addr();
-    let double_server = rpc::Server::new(server::Config::default())
+    let double_server = rpc::Server::default()
         .incoming(double_listener)
         .take(1)
         .respond_with(double::serve(DoubleServer { add_client }));
@@ -102,10 +102,6 @@ async fn run() -> io::Result<()> {
 
 fn main() {
     env_logger::init();
-    tokio::run(
-        run()
-            .map_err(|e| panic!(e))
-            .boxed()
-            .compat(),
-    );
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+    tokio::run(run().map_err(|e| panic!(e)).boxed().compat());
 }

tarpc/examples/service_registry.rs

@@ -0,0 +1,414 @@
+#![feature(
+    async_await,
+    await_macro,
+    futures_api,
+    arbitrary_self_types,
+    proc_macro_hygiene,
+    impl_trait_in_bindings
+)]
+
+mod registry {
+    use bytes::Bytes;
+    use futures::{
+        future::{ready, Ready},
+        prelude::*,
+    };
+    use serde::{Deserialize, Serialize};
+    use std::{
+        io,
+        pin::Pin,
+        sync::Arc,
+        task::{Context, Poll},
+    };
+    use tarpc::{
+        client::{self, Client},
+        context,
+    };
+
+    /// A request to a named service.
+    #[derive(Serialize, Deserialize)]
+    pub struct ServiceRequest {
+        service_name: String,
+        request: Bytes,
+    }
+
+    /// A response from a named service.
+    #[derive(Serialize, Deserialize)]
+    pub struct ServiceResponse {
+        response: Bytes,
+    }
+
+    /// A list of registered services.
+    pub struct Registry<Services> {
+        registrations: Services,
+    }
+
+    impl Default for Registry<Nil> {
+        fn default() -> Self {
+            Registry { registrations: Nil }
+        }
+    }
+
+    impl<Services: MaybeServe + Sync> Registry<Services> {
+        /// Returns a function that serves requests for the registered services.
+        pub fn serve(
+            self,
+        ) -> impl FnOnce(
+            context::Context,
+            ServiceRequest,
+        ) -> Either<Services::Future, Ready<io::Result<ServiceResponse>>>
+                         + Clone {
+            let registrations = Arc::new(self.registrations);
+            move |cx, req: ServiceRequest| match registrations.serve(cx, &req) {
+                Some(serve) => Either::Left(serve),
+                None => Either::Right(ready(Err(io::Error::new(
+                    io::ErrorKind::NotFound,
+                    format!("Service '{}' not registered", req.service_name),
+                )))),
+            }
+        }
+
+        /// Registers `serve` with the given `name` using the given serialization scheme.
+        pub fn register<S, Req, Resp, RespFut, Ser, De>(
+            self,
+            name: String,
+            serve: S,
+            deserialize: De,
+            serialize: Ser,
+        ) -> Registry<Registration<impl Serve + Send + 'static, Services>>
+        where
+            Req: Send,
+            S: FnOnce(context::Context, Req) -> RespFut + Send + 'static + Clone,
+            RespFut: Future<Output = io::Result<Resp>> + Send + 'static,
+            De: FnOnce(Bytes) -> io::Result<Req> + Send + 'static + Clone,
+            Ser: FnOnce(Resp) -> io::Result<Bytes> + Send + 'static + Clone,
+        {
+            let registrations = Registration {
+                name: name,
+                serve: move |cx, req: Bytes| {
+                    async move {
+                        let req = deserialize.clone()(req)?;
+                        let response = await!(serve.clone()(cx, req))?;
+                        let response = serialize.clone()(response)?;
+                        Ok(ServiceResponse { response })
+                    }
+                },
+                rest: self.registrations,
+            };
+            Registry { registrations }
+        }
+    }
+
+    /// Creates a client that sends requests to a service
+    /// named `service_name`, over the given channel, using
+    /// the specified serialization scheme.
+    pub fn new_client<Req, Resp, Ser, De>(
+        service_name: String,
+        channel: &client::Channel<ServiceRequest, ServiceResponse>,
+        mut serialize: Ser,
+        mut deserialize: De,
+    ) -> client::MapResponse<
+        client::WithRequest<
+            client::Channel<ServiceRequest, ServiceResponse>,
+            impl FnMut(Req) -> ServiceRequest,
+        >,
+        impl FnMut(ServiceResponse) -> Resp,
+    >
+    where
+        Req: Send + 'static,
+        Resp: Send + 'static,
+        De: FnMut(Bytes) -> io::Result<Resp> + Clone + Send + 'static,
+        Ser: FnMut(Req) -> io::Result<Bytes> + Clone + Send + 'static,
+    {
+        channel
+            .clone()
+            .with_request(move |req| {
+                ServiceRequest {
+                    service_name: service_name.clone(),
+                    // TODO: shouldn't need to unwrap here. Maybe with_request should allow for
+                    // returning Result.
+                    request: serialize(req).unwrap(),
+                }
+            })
+            // TODO: same thing. Maybe this should be more like and_then rather than map.
+            .map_response(move |resp| deserialize(resp.response).unwrap())
+    }
+
+    /// Serves a request.
+    ///
+    /// This trait is mostly an implementation detail that isn't used outside of the registry
+    /// internals.
+    pub trait Serve: Clone + Send + 'static {
+        type Response: Future<Output = io::Result<ServiceResponse>> + Send + 'static;
+        fn serve(self, cx: context::Context, request: Bytes) -> Self::Response;
+    }
+
+    /// Serves a request if the request is for a registered service.
+    ///
+    /// This trait is mostly an implementation detail that isn't used outside of the registry
+    /// internals.
+    pub trait MaybeServe: Send + 'static {
+        type Future: Future<Output = io::Result<ServiceResponse>> + Send + 'static;
+
+        fn serve(&self, cx: context::Context, request: &ServiceRequest) -> Option<Self::Future>;
+    }
+
+    /// A registry starting with service S, followed by Rest.
+    ///
+    /// This type is mostly an implementation detail that is not used directly
+    /// outside of the registry internals.
+    pub struct Registration<S, Rest> {
+        /// The registered service's name. Must be unique across all registered services.
+        name: String,
+        /// The registered service.
+        serve: S,
+        /// Any remaining registered services.
+        rest: Rest,
+    }
+
+    /// An empty registry.
+    ///
+    /// This type is mostly an implementation detail that is not used directly
+    /// outside of the registry internals.
+    pub struct Nil;
+
+    impl MaybeServe for Nil {
+        type Future = futures::future::Ready<io::Result<ServiceResponse>>;
+
+        fn serve(&self, _: context::Context, _: &ServiceRequest) -> Option<Self::Future> {
+            None
+        }
+    }
+
+    impl<S, Rest> MaybeServe for Registration<S, Rest>
+    where
+        S: Serve,
+        Rest: MaybeServe,
+    {
+        type Future = Either<S::Response, Rest::Future>;
+
+        fn serve(&self, cx: context::Context, request: &ServiceRequest) -> Option<Self::Future> {
+            if self.name == request.service_name {
+                Some(Either::Left(
+                    self.serve.clone().serve(cx, request.request.clone()),
+                ))
+            } else {
+                self.rest.serve(cx, request).map(Either::Right)
+            }
+        }
+    }
+
+    /// Wraps either of two future types that both resolve to the same output type.
+    #[derive(Debug)]
+    #[must_use = "futures do nothing unless polled"]
+    pub enum Either<Left, Right> {
+        Left(Left),
+        Right(Right),
+    }
+
+    impl<Output, Left, Right> Future for Either<Left, Right>
+    where
+        Left: Future<Output = Output>,
+        Right: Future<Output = Output>,
+    {
+        type Output = Output;
+
+        fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Output> {
+            unsafe {
+                match Pin::get_unchecked_mut(self) {
+                    Either::Left(car) => Pin::new_unchecked(car).poll(cx),
+                    Either::Right(cdr) => Pin::new_unchecked(cdr).poll(cx),
+                }
+            }
+        }
+    }
+
+    impl<Resp, F> Serve for F
+    where
+        F: FnOnce(context::Context, Bytes) -> Resp + Clone + Send + 'static,
+        Resp: Future<Output = io::Result<ServiceResponse>> + Send + 'static,
+    {
+        type Response = Resp;
+
+        fn serve(self, cx: context::Context, request: Bytes) -> Resp {
+            self(cx, request)
+        }
+    }
+}
+
+// Example
+use bytes::Bytes;
+use futures::{
+    compat::Executor01CompatExt,
+    future::{ready, Ready},
+    prelude::*,
+};
+use serde::{Deserialize, Serialize};
+use std::{
+    collections::HashMap,
+    io,
+    sync::{Arc, RwLock},
+};
+use tarpc::{client, context, server::Handler};
+
+fn deserialize<Req>(req: Bytes) -> io::Result<Req>
+where
+    Req: for<'a> Deserialize<'a> + Send,
+{
+    bincode::deserialize(req.as_ref()).map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+}
+
+fn serialize<Resp>(resp: Resp) -> io::Result<Bytes>
+where
+    Resp: Serialize,
+{
+    Ok(bincode::serialize(&resp)
+        .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?
+        .into())
+}
+
+mod write_service {
+    tarpc::service! {
+        rpc write(key: String, value: String);
+    }
+}
+
+mod read_service {
+    tarpc::service! {
+        rpc read(key: String) -> Option<String>;
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+struct Server {
+    data: Arc<RwLock<HashMap<String, String>>>,
+}
+
+impl write_service::Service for Server {
+    type WriteFut = Ready<()>;
+
+    fn write(self, _: context::Context, key: String, value: String) -> Self::WriteFut {
+        self.data.write().unwrap().insert(key, value);
+        ready(())
+    }
+}
+
+impl read_service::Service for Server {
+    type ReadFut = Ready<Option<String>>;
+
+    fn read(self, _: context::Context, key: String) -> Self::ReadFut {
+        ready(self.data.read().unwrap().get(&key).cloned())
+    }
+}
+
+trait DefaultSpawn {
+    fn spawn(self);
+}
+
+impl<F> DefaultSpawn for F
+where
+    F: Future<Output = ()> + Send + 'static,
+{
+    fn spawn(self) {
+        tokio_executor::spawn(self.unit_error().boxed().compat())
+    }
+}
+
+struct BincodeRegistry<Services> {
+    registry: registry::Registry<Services>,
+}
+
+impl Default for BincodeRegistry<registry::Nil> {
+    fn default() -> Self {
+        BincodeRegistry {
+            registry: registry::Registry::default(),
+        }
+    }
+}
+
+impl<Services: registry::MaybeServe + Sync> BincodeRegistry<Services> {
+    fn serve(
+        self,
+    ) -> impl FnOnce(
+        context::Context,
+        registry::ServiceRequest,
+    ) -> registry::Either<
+        Services::Future,
+        Ready<io::Result<registry::ServiceResponse>>,
+    > + Clone {
+        self.registry.serve()
+    }
+
+    fn register<S, Req, Resp, RespFut>(
+        self,
+        name: String,
+        serve: S,
+    ) -> BincodeRegistry<registry::Registration<impl registry::Serve + Send + 'static, Services>>
+    where
+        Req: for<'a> Deserialize<'a> + Send + 'static,
+        Resp: Serialize + 'static,
+        S: FnOnce(context::Context, Req) -> RespFut + Send + 'static + Clone,
+        RespFut: Future<Output = io::Result<Resp>> + Send + 'static,
+    {
+        let registry = self.registry.register(name, serve, deserialize, serialize);
+        BincodeRegistry { registry }
+    }
+}
+
+pub fn new_client<Req, Resp>(
+    service_name: String,
+    channel: &client::Channel<registry::ServiceRequest, registry::ServiceResponse>,
+) -> client::MapResponse<
+    client::WithRequest<
+        client::Channel<registry::ServiceRequest, registry::ServiceResponse>,
+        impl FnMut(Req) -> registry::ServiceRequest,
+    >,
+    impl FnMut(registry::ServiceResponse) -> Resp,
+>
+where
+    Req: Serialize + Send + 'static,
+    Resp: for<'a> Deserialize<'a> + Send + 'static,
+{
+    registry::new_client(service_name, channel, serialize, deserialize)
+}
+
+async fn run() -> io::Result<()> {
+    let server = Server::default();
+    let registry = BincodeRegistry::default()
+        .register(
+            "WriteService".to_string(),
+            write_service::serve(server.clone()),
+        )
+        .register(
+            "ReadService".to_string(),
+            read_service::serve(server.clone()),
+        );
+
+    let listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let server_addr = listener.local_addr();
+    let server = tarpc::Server::default()
+        .incoming(listener)
+        .take(1)
+        .respond_with(registry.serve());
+    tokio_executor::spawn(server.unit_error().boxed().compat());
+
+    let transport = await!(bincode_transport::connect(&server_addr))?;
+    let channel = await!(client::new(client::Config::default(), transport))?;
+
+    let write_client = new_client("WriteService".to_string(), &channel);
+    let mut write_client = write_service::Client::from(write_client);
+
+    let read_client = new_client("ReadService".to_string(), &channel);
+    let mut read_client = read_service::Client::from(read_client);
+
+    await!(write_client.write(context::current(), "key".to_string(), "val".to_string()))?;
+    let val = await!(read_client.read(context::current(), "key".to_string()))?;
+    println!("{:?}", val);
+
+    Ok(())
+}
+
+fn main() {
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+    tokio::run(run().boxed().map_err(|e| panic!(e)).boxed().compat());
+}

tarpc/rustfmt.toml

@@ -1 +1 @@
-edition = "Edition2018"
+edition = "2018"

tarpc/src/lib.rs

@@ -4,123 +4,13 @@
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-//! tarpc is an RPC framework for rust with a focus on ease of use. Defining a
-//! service can be done in just a few lines of code, and most of the boilerplate of
-//! writing a server is taken care of for you.
-//!
-//! ## What is an RPC framework?
-//! "RPC" stands for "Remote Procedure Call," a function call where the work of
-//! producing the return value is being done somewhere else. When an rpc function is
-//! invoked, behind the scenes the function contacts some other process somewhere
-//! and asks them to evaluate the function instead. The original function then
-//! returns the value produced by the other process.
-//!
-//! RPC frameworks are a fundamental building block of most microservices-oriented
-//! architectures. Two well-known ones are [gRPC](http://www.grpc.io) and
-//! [Cap'n Proto](https://capnproto.org/).
-//!
-//! tarpc differentiates itself from other RPC frameworks by defining the schema in code,
-//! rather than in a separate language such as .proto. This means there's no separate compilation
-//! process, and no cognitive context switching between different languages. Additionally, it
-//! works with the community-backed library serde: any serde-serializable type can be used as
-//! arguments to tarpc fns.
-//!
-//! ## Example
-//!
-//! Here's a small service.
-//!
-//! ```rust
-//! #![feature(futures_api, pin, arbitrary_self_types, await_macro, async_await, proc_macro_hygiene)]
-//!
-//!
-//! use futures::{
-//!     compat::TokioDefaultSpawner,
-//!     future::{self, Ready},
-//!     prelude::*,
-//! };
-//! use tarpc::{
-//!     client, context,
-//!     server::{self, Handler, Server},
-//! };
-//! use std::io;
-//!
-//! // This is the service definition. It looks a lot like a trait definition.
-//! // It defines one RPC, hello, which takes one arg, name, and returns a String.
-//! tarpc::service! {
-//!     /// Returns a greeting for name.
-//!     rpc hello(name: String) -> String;
-//! }
-//!
-//! // This is the type that implements the generated Service trait. It is the business logic
-//! // and is used to start the server.
-//! #[derive(Clone)]
-//! struct HelloServer;
-//!
-//! impl Service for HelloServer {
-//!     // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
-//!     // an associated type representing the future output by the fn.
-//!
-//!     type HelloFut = Ready<String>;
-//!
-//!     fn hello(&self, _: context::Context, name: String) -> Self::HelloFut {
-//!         future::ready(format!("Hello, {}!", name))
-//!     }
-//! }
-//!
-//! async fn run() -> io::Result<()> {
-//!     // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
-//!     // to start up a serde-powered bincode serialization strategy over TCP.
-//!     let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
-//!     let addr = transport.local_addr();
-//!
-//!     // The server is configured with the defaults.
-//!     let server = Server::new(server::Config::default())
-//!         // Server can listen on any type that implements the Transport trait.
-//!         .incoming(transport)
-//!         // Close the stream after the client connects
-//!         .take(1)
-//!         // serve is generated by the service! macro. It takes as input any type implementing
-//!         // the generated Service trait.
-//!         .respond_with(serve(HelloServer));
-//!
-//!     tokio_executor::spawn(server.unit_error().boxed().compat());
-//!
-//!     let transport = await!(bincode_transport::connect(&addr))?;
-//!
-//!     // new_stub is generated by the service! macro. Like Server, it takes a config and any
-//!     // Transport as input, and returns a Client, also generated by the macro.
-//!     // by the service mcro.
-//!     let mut client = await!(new_stub(client::Config::default(), transport))?;
-//!
-//!     // The client has an RPC method for each RPC defined in service!. It takes the same args
-//!     // as defined, with the addition of a Context, which is always the first arg. The Context
-//!     // specifies a deadline and trace information which can be helpful in debugging requests.
-//!     let hello = await!(client.hello(context::current(), "Stim".to_string()))?;
-//!
-//!     println!("{}", hello);
-//!
-//!     Ok(())
-//! }
-//!
-//! fn main() {
-//!     tarpc::init(TokioDefaultSpawner);
-//!     tokio::run(run()
-//!             .map_err(|e| eprintln!("Oh no: {}", e))
-//!             .boxed()
-//!             .compat(),
-//!     );
-//! }
-//! ```
-
+#![doc(include = "../README.md")]
 #![deny(missing_docs, missing_debug_implementations)]
-#![feature(
-    futures_api,
-    pin,
-    await_macro,
-    async_await,
-    decl_macro,
+#![feature(async_await, external_doc)]
+#![cfg_attr(
+    test,
+    feature(futures_api, await_macro, proc_macro_hygiene, arbitrary_self_types)
 )]
-#![cfg_attr(test, feature(proc_macro_hygiene, arbitrary_self_types))]
 
 #[doc(hidden)]
 pub use futures;

tarpc/src/macros.rs

@@ -51,6 +51,9 @@ macro_rules! add_serde_if_enabled {
 ///
 #[macro_export]
 macro_rules! service {
+    () => {
+        compile_error!("Must define at least one RPC method.");
+    };
 // Entry point
     (
         $(
@@ -112,24 +115,26 @@ macro_rules! service {
         )*
     ) => {
         $crate::add_serde_if_enabled! {
+            /// The request sent over the wire from the client to the server.
             #[derive(Debug)]
-            #[doc(hidden)]
             #[allow(non_camel_case_types, unused)]
             --
-            pub enum Request__ {
+            pub enum Request {
                 $(
+                    $(#[$attr])*
                     $fn_name{ $($arg: $in_,)* }
                 ),*
             }
         }
 
         $crate::add_serde_if_enabled! {
+            /// The response sent over the wire from the server to the client.
             #[derive(Debug)]
-            #[doc(hidden)]
             #[allow(non_camel_case_types, unused)]
             --
-            pub enum Response__ {
+            pub enum Response {
                 $(
+                    $(#[$attr])*
                     $fn_name($out)
                 ),*
             }
@@ -149,37 +154,39 @@ macro_rules! service {
                 }
 
                 $(#[$attr])*
-                fn $fn_name(&self, ctx: $crate::context::Context, $($arg:$in_),*) -> $crate::ty_snake_to_camel!(Self::$fn_name);
+                fn $fn_name(self, ctx: $crate::context::Context, $($arg:$in_),*) -> $crate::ty_snake_to_camel!(Self::$fn_name);
             )*
         }
 
         // TODO: use an existential type instead of this when existential types work.
+        /// A future resolving to a server [`Response`].
         #[allow(non_camel_case_types)]
-        pub enum Response<S: Service> {
+        pub enum ResponseFut<S: Service> {
             $(
+                $(#[$attr])*
                 $fn_name($crate::ty_snake_to_camel!(<S as Service>::$fn_name)),
             )*
         }
 
-        impl<S: Service> ::std::fmt::Debug for Response<S> {
+        impl<S: Service> ::std::fmt::Debug for ResponseFut<S> {
             fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
                 fmt.debug_struct("Response").finish()
             }
         }
 
-        impl<S: Service> ::std::future::Future for Response<S> {
-            type Output = ::std::io::Result<Response__>;
+        impl<S: Service> ::std::future::Future for ResponseFut<S> {
+            type Output = ::std::io::Result<Response>;
 
-            fn poll(self: ::std::pin::Pin<&mut Self>, waker: &::std::task::LocalWaker)
-                -> ::std::task::Poll<::std::io::Result<Response__>>
+            fn poll(self: ::std::pin::Pin<&mut Self>, cx: &mut ::std::task::Context<'_>)
+                -> ::std::task::Poll<::std::io::Result<Response>>
             {
                 unsafe {
-                    match ::std::pin::Pin::get_mut_unchecked(self) {
+                    match ::std::pin::Pin::get_unchecked_mut(self) {
                         $(
-                            Response::$fn_name(resp) =>
+                            ResponseFut::$fn_name(resp) =>
                                 ::std::pin::Pin::new_unchecked(resp)
-                                    .poll(waker)
-                                    .map(Response__::$fn_name)
+                                    .poll(cx)
+                                    .map(Response::$fn_name)
                                     .map(Ok),
                         )*
                     }
@@ -189,13 +196,13 @@ macro_rules! service {
 
         /// Returns a serving function to use with rpc::server::Server.
         pub fn serve<S: Service>(service: S)
-            -> impl FnMut($crate::context::Context, Request__) -> Response<S> + Send + 'static + Clone {
+            -> impl FnOnce($crate::context::Context, Request) -> ResponseFut<S> + Send + 'static + Clone {
                 move |ctx, req| {
                     match req {
                         $(
-                            Request__::$fn_name{ $($arg,)* } => {
-                                let resp = Service::$fn_name(&mut service.clone(), ctx, $($arg),*);
-                                Response::$fn_name(resp)
+                            Request::$fn_name{ $($arg,)* } => {
+                                let resp = Service::$fn_name(service.clone(), ctx, $($arg),*);
+                                ResponseFut::$fn_name(resp)
                             }
                         )*
                     }
@@ -205,30 +212,40 @@ macro_rules! service {
         #[allow(unused)]
         #[derive(Clone, Debug)]
         /// The client stub that makes RPC calls to the server. Exposes a Future interface.
-        pub struct Client($crate::client::Client<Request__, Response__>);
+        pub struct Client<C = $crate::client::Channel<Request, Response>>(C);
 
         /// Returns a new client stub that sends requests over the given transport.
         pub async fn new_stub<T>(config: $crate::client::Config, transport: T)
             -> ::std::io::Result<Client>
         where
             T: $crate::Transport<
-                    Item = $crate::Response<Response__>,
-                    SinkItem = $crate::ClientMessage<Request__>> + Send,
+                    Item = $crate::Response<Response>,
+                    SinkItem = $crate::ClientMessage<Request>> + Send + 'static,
         {
-            Ok(Client(await!($crate::client::Client::new(config, transport))?))
+            Ok(Client(await!($crate::client::new(config, transport))?))
         }
 
-        impl Client {
+        impl<C> From<C> for Client<C>
+            where for <'a> C: $crate::Client<'a, Request, Response = Response>
+        {
+            fn from(client: C) -> Self {
+                Client(client)
+            }
+        }
+
+        impl<C> Client<C>
+            where for<'a> C: $crate::Client<'a, Request, Response = Response>
+        {
             $(
                 #[allow(unused)]
                 $(#[$attr])*
                 pub fn $fn_name(&mut self, ctx: $crate::context::Context, $($arg: $in_),*)
                     -> impl ::std::future::Future<Output = ::std::io::Result<$out>> + '_ {
-                    let request__ = Request__::$fn_name { $($arg,)* };
-                    let resp = self.0.call(ctx, request__);
+                    let request__ = Request::$fn_name { $($arg,)* };
+                    let resp = $crate::Client::call(&mut self.0, ctx, request__);
                     async move {
                         match await!(resp)? {
-                            Response__::$fn_name(msg__) => ::std::result::Result::Ok(msg__),
+                            Response::$fn_name(msg__) => ::std::result::Result::Ok(msg__),
                             _ => unreachable!(),
                         }
                     }
@@ -265,15 +282,11 @@ mod syntax_test {
 #[cfg(test)]
 mod functional_test {
     use futures::{
-        compat::TokioDefaultSpawner,
+        compat::Executor01CompatExt,
         future::{ready, Ready},
         prelude::*,
     };
-    use rpc::{
-        client, context,
-        server::{self, Handler},
-        transport::channel,
-    };
+    use rpc::{client, context, server::Handler, transport::channel};
     use std::io;
     use tokio::runtime::current_thread;
 
@@ -288,13 +301,13 @@ mod functional_test {
     impl Service for Server {
         type AddFut = Ready<i32>;
 
-        fn add(&self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
+        fn add(self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
             ready(x + y)
         }
 
         type HeyFut = Ready<String>;
 
-        fn hey(&self, _: context::Context, name: String) -> Self::HeyFut {
+        fn hey(self, _: context::Context, name: String) -> Self::HeyFut {
             ready(format!("Hey, {}.", name))
         }
     }
@@ -302,17 +315,17 @@ mod functional_test {
     #[test]
     fn sequential() {
         let _ = env_logger::try_init();
-        rpc::init(TokioDefaultSpawner);
+        rpc::init(tokio::executor::DefaultExecutor::current().compat());
 
         let test = async {
             let (tx, rx) = channel::unbounded();
             tokio_executor::spawn(
-                rpc::Server::new(server::Config::default())
+                crate::Server::default()
                     .incoming(stream::once(ready(Ok(rx))))
                     .respond_with(serve(Server))
                     .unit_error()
                     .boxed()
-                    .compat()
+                    .compat(),
             );
 
             let mut client = await!(new_stub(client::Config::default(), tx))?;
@@ -331,17 +344,17 @@ mod functional_test {
     #[test]
     fn concurrent() {
         let _ = env_logger::try_init();
-        rpc::init(TokioDefaultSpawner);
+        rpc::init(tokio::executor::DefaultExecutor::current().compat());
 
         let test = async {
             let (tx, rx) = channel::unbounded();
             tokio_executor::spawn(
-                rpc::Server::new(server::Config::default())
+                rpc::Server::default()
                     .incoming(stream::once(ready(Ok(rx))))
                     .respond_with(serve(Server))
                     .unit_error()
                     .boxed()
-                    .compat()
+                    .compat(),
             );
 
             let client = await!(new_stub(client::Config::default(), tx))?;

tarpc/tests/latency.rs

@@ -7,22 +7,19 @@
 #![feature(
     test,
     arbitrary_self_types,
-    pin,
     integer_atomics,
     futures_api,
     generators,
     await_macro,
     async_await,
-    proc_macro_hygiene,
+    proc_macro_hygiene
 )]
 
-extern crate test;
-
-use self::test::stats::Stats;
-use futures::{compat::TokioDefaultSpawner, future, prelude::*};
+use futures::{compat::Executor01CompatExt, future, prelude::*};
+use libtest::stats::Stats;
 use rpc::{
     client, context,
-    server::{self, Handler, Server},
+    server::{Handler, Server},
 };
 use std::{
     io,
@@ -41,7 +38,7 @@ struct Serve;
 impl ack::Service for Serve {
     type AckFut = future::Ready<()>;
 
-    fn ack(&self, _: context::Context) -> Self::AckFut {
+    fn ack(self, _: context::Context) -> Self::AckFut {
         future::ready(())
     }
 }
@@ -51,13 +48,13 @@ async fn bench() -> io::Result<()> {
     let addr = listener.local_addr();
 
     tokio_executor::spawn(
-        Server::new(server::Config::default())
+        Server::default()
             .incoming(listener)
             .take(1)
             .respond_with(ack::serve(Serve))
             .unit_error()
             .boxed()
-            .compat()
+            .compat(),
     );
 
     let conn = await!(bincode_transport::connect(&addr))?;
@@ -120,12 +117,7 @@ async fn bench() -> io::Result<()> {
 #[test]
 fn bench_small_packet() {
     env_logger::init();
-    tarpc::init(TokioDefaultSpawner);
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
 
-    tokio::run(
-        bench()
-            .map_err(|e| panic!(e.to_string()))
-            .boxed()
-            .compat(),
-    )
+    tokio::run(bench().map_err(|e| panic!(e.to_string())).boxed().compat())
 }

trace/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tarpc-trace"
-version = "0.1.0"
+version = "0.2.0"
 authors = ["tikue <tikue@google.com>"]
 edition = '2018'
 license = "MIT"
@@ -13,7 +13,7 @@ readme = "../README.md"
 description = "foundations for tracing in tarpc"
 
 [dependencies]
-rand = "0.5"
+rand = "0.6"
 
 [dependencies.serde]
 version = "1.0"

trace/rustfmt.toml

@@ -1 +1 @@
-edition = "Edition2018"
+edition = "2018"

trace/src/lib.rs

@@ -27,10 +27,7 @@ use std::{
 /// Consists of a span identifying an event, an optional parent span identifying a causal event
 /// that triggered the current span, and a trace with which all related spans are associated.
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Context {
     /// An identifier of the trace associated with the current context. A trace ID is typically
     /// created at a root span and passed along through all causal events.
@@ -50,18 +47,12 @@ pub struct Context {
 /// A 128-bit UUID identifying a trace. All spans caused by the same originating span share the
 /// same trace ID.
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct TraceId(u128);
 
 /// A 64-bit identifier of a span within a trace. The identifier is unique within the span's trace.
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Serialize, serde::Deserialize)
-)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct SpanId(u64);
 
 impl Context {
@@ -80,7 +71,7 @@ impl TraceId {
     /// Returns a random trace ID that can be assumed to be globally unique if `rng` generates
     /// actually-random numbers.
     pub fn random<R: Rng>(rng: &mut R) -> Self {
-        TraceId((rng.next_u64() as u128) << mem::size_of::<u64>() | rng.next_u64() as u128)
+        TraceId(u128::from(rng.next_u64()) << mem::size_of::<u64>() | u128::from(rng.next_u64()))
     }
 }