feat(net): Split Ssl into SslClient and SslServer

SSL libraries other than OpenSSL don't necessarily have the ability to
easily create server and client side connections at the same time. This
is backwards compatible due to blanket impls.

Closes #756

Author: sfackler

src/net.rs

@@ -410,7 +410,9 @@ impl<F> NetworkConnector for F where F: Fn(&str, u16, &str) -> io::Result<TcpStr
     }
 }
 
-/// An abstraction to allow any SSL implementation to be used with HttpsStreams.
+/// Deprecated
+///
+/// Use `SslClient` and `SslServer` instead.
 pub trait Ssl {
     /// The protected stream.
     type Stream: NetworkStream + Send + Clone;
@@ -420,6 +422,38 @@ pub trait Ssl {
     fn wrap_server(&self, stream: HttpStream) -> ::Result<Self::Stream>;
 }
 
+/// An abstraction to allow any SSL implementation to be used with client-side HttpsStreams.
+pub trait SslClient {
+    /// The protected stream.
+    type Stream: NetworkStream + Send + Clone;
+    /// Wrap a client stream with SSL.
+    fn wrap_client(&self, stream: HttpStream, host: &str) -> ::Result<Self::Stream>;
+}
+
+/// An abstraction to allow any SSL implementation to be used with server-side HttpsStreams.
+pub trait SslServer {
+    /// The protected stream.
+    type Stream: NetworkStream + Send + Clone;
+    /// Wrap a server stream with SSL.
+    fn wrap_server(&self, stream: HttpStream) -> ::Result<Self::Stream>;
+}
+
+impl<S: Ssl> SslClient for S {
+    type Stream = <S as Ssl>::Stream;
+
+    fn wrap_client(&self, stream: HttpStream, host: &str) -> ::Result<Self::Stream> {
+        Ssl::wrap_client(self, stream, host)
+    }
+}
+
+impl<S: Ssl> SslServer for S {
+    type Stream = <S as Ssl>::Stream;
+
+    fn wrap_server(&self, stream: HttpStream) -> ::Result<Self::Stream> {
+        Ssl::wrap_server(self, stream)
+    }
+}
+
 /// A stream over the HTTP protocol, possibly protected by SSL.
 #[derive(Debug, Clone)]
 pub enum HttpsStream<S: NetworkStream> {
@@ -493,7 +527,7 @@ impl<S: NetworkStream> NetworkStream for HttpsStream<S> {
 
 /// A Http Listener over SSL.
 #[derive(Clone)]
-pub struct HttpsListener<S: Ssl> {
+pub struct HttpsListener<S: SslServer> {
     listener: HttpListener,
     ssl: S,
 }
@@ -516,7 +550,7 @@ impl<S: Ssl> HttpsListener<S> {
     }
 }
 
-impl<S: Ssl + Clone> NetworkListener for HttpsListener<S> {
+impl<S: SslServer + Clone> NetworkListener for HttpsListener<S> {
     type Stream = S::Stream;
 
     #[inline]
@@ -532,18 +566,18 @@ impl<S: Ssl + Clone> NetworkListener for HttpsListener<S> {
 
 /// A connector that can protect HTTP streams using SSL.
 #[derive(Debug, Default)]
-pub struct HttpsConnector<S: Ssl> {
+pub struct HttpsConnector<S: SslClient> {
     ssl: S
 }
 
-impl<S: Ssl> HttpsConnector<S> {
+impl<S: SslClient> HttpsConnector<S> {
     /// Create a new connector using the provided SSL implementation.
     pub fn new(s: S) -> HttpsConnector<S> {
         HttpsConnector { ssl: s }
     }
 }
 
-impl<S: Ssl> NetworkConnector for HttpsConnector<S> {
+impl<S: SslClient> NetworkConnector for HttpsConnector<S> {
     type Stream = HttpsStream<S::Stream>;
 
     fn connect(&self, host: &str, port: u16, scheme: &str) -> ::Result<Self::Stream> {