feat(server): add from_tcp method

Adds the `from_tcp()` method as per
hyperium#1602.

fix clippy changes

src/server/mod.rs

@@ -51,21 +51,31 @@
 //! ```
 
 pub mod conn;
-#[cfg(feature = "runtime")] mod tcp;
+#[cfg(feature = "runtime")]
+mod tcp;
 
 use std::fmt;
-#[cfg(feature = "runtime")] use std::net::SocketAddr;
-#[cfg(feature = "runtime")] use std::time::Duration;
+#[cfg(feature = "runtime")]
+use std::net;
+#[cfg(feature = "runtime")]
+use std::net::SocketAddr;
+#[cfg(feature = "runtime")]
+use std::time::Duration;
 
-use futures::{Future, Stream, Poll};
+use futures::{Future, Poll, Stream};
 use tokio_io::{AsyncRead, AsyncWrite};
+#[cfg(feature = "runtime")]
+use tokio_reactor;
+#[cfg(feature = "runtime")]
+use tokio_tcp;
 
 use body::{Body, Payload};
 use service::{NewService, Service};
 // Renamed `Http` as `Http_` for now so that people upgrading don't see an
 // error that `hyper::server::Http` is private...
 use self::conn::{Http as Http_, SpawnAll};
-#[cfg(feature = "runtime")] use self::tcp::{AddrIncoming};
+#[cfg(feature = "runtime")]
+use self::tcp::AddrIncoming;
 
 /// A listening HTTP server that accepts connections in both HTTP1 and HTTP2 by default.
 ///
@@ -96,6 +106,19 @@ impl<I> Server<I, ()> {
     }
 }
 
+impl Server<tokio_tcp::Incoming, ()> {
+    /// Create a new instance from a `std::net::TcpListener` instance.
+    #[cfg(feature = "runtime")]
+    pub fn from_tcp(
+        listener: net::TcpListener,
+    ) -> Result<Builder<tokio_tcp::Incoming>, ::Error> {
+        let handle = tokio_reactor::Handle::current();
+        let listener = tokio_tcp::TcpListener::from_std(listener, &handle)
+          .map_err(|err| ::Error::new_listen(err))?;
+        Ok(Self::builder(listener.incoming()))
+    }
+}
+
 #[cfg(feature = "runtime")]
 impl Server<AddrIncoming, ()> {
     /// Binds to the provided address, and returns a [`Builder`](Builder).
@@ -275,4 +298,3 @@ impl Builder<AddrIncoming> {
         self
     }
 }
-