feat(net): add socket timeouts to Server and Client

While these methods are marked unstable in libstd, this is behind a
feature flag, `timeouts`. The Client and Server both have
`set_read_timeout` and `set_write_timeout` methods, that will affect all
connections with that entity.

BREAKING CHANGE: Any custom implementation of NetworkStream must now
  implement `set_read_timeout` and `set_write_timeout`, so those will
  break. Most users who only use the provided streams should work with
  no changes needed.

Closes #315

src/client/mod.rs

@@ -59,13 +59,16 @@ use std::default::Default;
 use std::io::{self, copy, Read};
 use std::iter::Extend;
 
+#[cfg(feature = "timeouts")]
+use std::time::Duration;
+
 use url::UrlParser;
 use url::ParseError as UrlError;
 
 use header::{Headers, Header, HeaderFormat};
 use header::{ContentLength, Location};
 use method::Method;
-use net::{NetworkConnector, NetworkStream};
+use net::{NetworkConnector, NetworkStream, Fresh};
 use {Url};
 use Error;
 
@@ -87,7 +90,9 @@ pub struct Client {
     protocol: Box<Protocol + Send + Sync>,
     redirect_policy: RedirectPolicy,
     #[cfg(feature = "timeouts")]
-    read_timeout: Option<Duration>
+    read_timeout: Option<Duration>,
+    #[cfg(feature = "timeouts")]
+    write_timeout: Option<Duration>,
 }
 
 impl Client {
@@ -108,11 +113,23 @@ impl Client {
         Client::with_protocol(Http11Protocol::with_connector(connector))
     }
 
+    #[cfg(not(feature = "timeouts"))]
     /// Create a new client with a specific `Protocol`.
     pub fn with_protocol<P: Protocol + Send + Sync + 'static>(protocol: P) -> Client {
         Client {
             protocol: Box::new(protocol),
-            redirect_policy: Default::default()
+            redirect_policy: Default::default(),
+        }
+    }
+
+    #[cfg(feature = "timeouts")]
+    /// Create a new client with a specific `Protocol`.
+    pub fn with_protocol<P: Protocol + Send + Sync + 'static>(protocol: P) -> Client {
+        Client {
+            protocol: Box::new(protocol),
+            redirect_policy: Default::default(),
+            read_timeout: None,
+            write_timeout: None,
         }
     }
 
@@ -127,6 +144,12 @@ impl Client {
         self.read_timeout = dur;
     }
 
+    /// Set the write timeout value for all requests.
+    #[cfg(feature = "timeouts")]
+    pub fn set_write_timeout(&mut self, dur: Option<Duration>) {
+        self.write_timeout = dur;
+    }
+
     /// Build a Get request.
     pub fn get<U: IntoUrl>(&self, url: U) -> RequestBuilder<U> {
         self.request(Method::Get, url)
@@ -236,6 +259,20 @@ impl<'a, U: IntoUrl> RequestBuilder<'a, U> {
             let mut req = try!(Request::with_message(method.clone(), url.clone(), message));
             headers.as_ref().map(|headers| req.headers_mut().extend(headers.iter()));
 
+            #[cfg(not(feature = "timeouts"))]
+            fn set_timeouts(_req: &mut Request<Fresh>, _client: &Client) -> ::Result<()> {
+                Ok(())
+            }
+
+            #[cfg(feature = "timeouts")]
+            fn set_timeouts(req: &mut Request<Fresh>, client: &Client) -> ::Result<()> {
+                try!(req.set_write_timeout(client.write_timeout));
+                try!(req.set_read_timeout(client.read_timeout));
+                Ok(())
+            }
+
+            try!(set_timeouts(&mut req, &client));
+
             match (can_have_body, body.as_ref()) {
                 (true, Some(body)) => match body.size() {
                     Some(size) => req.headers_mut().set(ContentLength(size)),