feat(client): remove generic parameter for Connector

Closes #379

BREAKING CHANGE: For people using the default HttpConnector and Client,
    everything should continue to just work. If the Client has been
    used with a generic parameter, it should be removed.

    However, there were some breaking changes to the internals of
    NetworkConnectors. Specifically, they no longer return a
    NetworkStream, but instead a Into<Box<NetworkStream + Send>>. All
    implementations of NetworkStream should continue to just work,
    however.

    Possible breakages could come from the stricter usage of Send
    throughout the Client API.

src/client/mod.rs

@@ -27,7 +27,7 @@ use url::ParseError as UrlError;
 use header::{Headers, Header, HeaderFormat};
 use header::{ContentLength, Location};
 use method::Method;
-use net::{NetworkConnector, HttpConnector, ContextVerifier};
+use net::{NetworkConnector, NetworkStream, HttpConnector, ContextVerifier};
 use status::StatusClass::Redirection;
 use {Url, HttpResult};
 use HttpError::HttpUriError;
@@ -41,68 +41,65 @@ pub mod response;
 /// A Client to use additional features with Requests.
 ///
 /// Clients can handle things such as: redirect policy.
-pub struct Client<C> {
-    connector: C,
+pub struct Client {
+    connector: Connector,
     redirect_policy: RedirectPolicy,
 }
 
-impl<'v> Client<HttpConnector<'v>> {
+impl Client {
 
     /// Create a new Client.
-    pub fn new() -> Client<HttpConnector<'v>> {
+    pub fn new() -> Client {
         Client::with_connector(HttpConnector(None))
     }
 
-    /// Set the SSL verifier callback for use with OpenSSL.
-    pub fn set_ssl_verifier(&mut self, verifier: ContextVerifier<'v>) {
-        self.connector = HttpConnector(Some(verifier));
-    }
-
-}
-
-impl<C: NetworkConnector> Client<C> {
-
     /// Create a new client with a specific connector.
-    pub fn with_connector(connector: C) -> Client<C> {
+    pub fn with_connector<C, S>(connector: C) -> Client
+    where C: NetworkConnector<Stream=S> + Send + 'static, S: NetworkStream + Send {
         Client {
-            connector: connector,
+            connector: with_connector(connector),
             redirect_policy: Default::default()
         }
     }
 
+    /// Set the SSL verifier callback for use with OpenSSL.
+    pub fn set_ssl_verifier(&mut self, verifier: ContextVerifier) {
+        self.connector = with_connector(HttpConnector(Some(verifier)));
+    }
+
     /// Set the RedirectPolicy.
     pub fn set_redirect_policy(&mut self, policy: RedirectPolicy) {
         self.redirect_policy = policy;
     }
 
     /// Build a Get request.
-    pub fn get<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U, C> {
+    pub fn get<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U> {
         self.request(Method::Get, url)
     }
 
     /// Build a Head request.
-    pub fn head<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U, C> {
+    pub fn head<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U> {
         self.request(Method::Head, url)
     }
 
     /// Build a Post request.
-    pub fn post<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U, C> {
+    pub fn post<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U> {
         self.request(Method::Post, url)
     }
 
     /// Build a Put request.
-    pub fn put<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U, C> {
+    pub fn put<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U> {
         self.request(Method::Put, url)
     }
 
     /// Build a Delete request.
-    pub fn delete<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U, C> {
+    pub fn delete<U: IntoUrl>(&mut self, url: U) -> RequestBuilder<U> {
         self.request(Method::Delete, url)
     }
 
 
     /// Build a new request using this Client.
-    pub fn request<U: IntoUrl>(&mut self, method: Method, url: U) -> RequestBuilder<U, C> {
+    pub fn request<U: IntoUrl>(&mut self, method: Method, url: U) -> RequestBuilder<U> {
         RequestBuilder {
             client: self,
             method: method,
@@ -113,34 +110,60 @@ impl<C: NetworkConnector> Client<C> {
     }
 }
 
+fn with_connector<C: NetworkConnector<Stream=S> + Send + 'static, S: NetworkStream + Send>(c: C) -> Connector {
+    Connector(Box::new(ConnAdapter(c)))
+}
+
+struct ConnAdapter<C: NetworkConnector + Send>(C);
+
+impl<C: NetworkConnector<Stream=S> + Send, S: NetworkStream + Send> NetworkConnector for ConnAdapter<C> {
+    type Stream = Box<NetworkStream + Send>;
+    #[inline]
+    fn connect(&mut self, host: &str, port: u16, scheme: &str)
+        -> io::Result<Box<NetworkStream + Send>> {
+        Ok(try!(self.0.connect(host, port, scheme)).into())
+    }
+}
+
+struct Connector(Box<NetworkConnector<Stream=Box<NetworkStream + Send>> + Send>);
+
+impl NetworkConnector for Connector {
+    type Stream = Box<NetworkStream + Send>;
+    #[inline]
+    fn connect(&mut self, host: &str, port: u16, scheme: &str)
+        -> io::Result<Box<NetworkStream + Send>> {
+        Ok(try!(self.0.connect(host, port, scheme)).into())
+    }
+}
+
 /// Options for an individual Request.
 ///
 /// One of these will be built for you if you use one of the convenience
 /// methods, such as `get()`, `post()`, etc.
-pub struct RequestBuilder<'a, U: IntoUrl, C: NetworkConnector + 'a> {
-    client: &'a mut Client<C>,
+pub struct RequestBuilder<'a, U: IntoUrl> {
+    client: &'a mut Client,
     url: U,
     headers: Option<Headers>,
     method: Method,
     body: Option<Body<'a>>,
 }
 
-impl<'a, U: IntoUrl, C: NetworkConnector> RequestBuilder<'a, U, C> {
+impl<'a, U: IntoUrl> RequestBuilder<'a, U> {
 
     /// Set a request body to be sent.
-    pub fn body<B: IntoBody<'a>>(mut self, body: B) -> RequestBuilder<'a, U, C> {
+    pub fn body<B: IntoBody<'a>>(mut self, body: B) -> RequestBuilder<'a, U> {
         self.body = Some(body.into_body());
         self
     }
 
     /// Add additional headers to the request.
-    pub fn headers(mut self, headers: Headers) -> RequestBuilder<'a, U, C> {
+    pub fn headers(mut self, headers: Headers) -> RequestBuilder<'a, U> {
         self.headers = Some(headers);
         self
     }
 
     /// Add an individual new header to the request.
-    pub fn header<H: Header + HeaderFormat>(mut self, header: H) -> RequestBuilder<'a, U, C> {
+    pub fn header<H: Header + HeaderFormat>(mut self, header: H) -> RequestBuilder<'a, U> {
         {
             let mut headers = match self.headers {
                 Some(ref mut h) => h,

src/client/request.rs

@@ -51,13 +51,11 @@ impl Request<Fresh> {
     pub fn with_connector<C, S>(method: method::Method, url: Url, connector: &mut C)
         -> HttpResult<Request<Fresh>> where
         C: NetworkConnector<Stream=S>,
-        S: NetworkStream + Send {
+        S: Into<Box<NetworkStream + Send>> {
         debug!("{} {}", method, url);
         let (host, port) = try!(get_host_and_port(&url));
 
-        let stream = try!(connector.connect(&*host, port, &*url.scheme));
-        // FIXME: Use Type ascription
-        let stream: Box<NetworkStream + Send> = Box::new(stream);
+        let stream = try!(connector.connect(&*host, port, &*url.scheme)).into();
         let stream = ThroughWriter(BufWriter::new(stream));
 
         let mut headers = Headers::new();

src/lib.rs

@@ -190,6 +190,7 @@ mod mimewrapper {
 
 #[allow(unconditional_recursion)]
 fn _assert_send<T: Send>() {
+    _assert_send::<Client>();
     _assert_send::<client::Request<net::Fresh>>();
     _assert_send::<client::Response>();
 }

src/net.rs

@@ -83,11 +83,17 @@ impl<T: NetworkStream + Send + Clone> StreamClone for T {
 /// A connector creates a NetworkStream.
 pub trait NetworkConnector {
     /// Type of Stream to create
-    type Stream: NetworkStream + Send;
+    type Stream: Into<Box<NetworkStream + Send>>;
     /// Connect to a remote address.
     fn connect(&mut self, host: &str, port: u16, scheme: &str) -> io::Result<Self::Stream>;
 }
 
+impl<T: NetworkStream + Send> From<T> for Box<NetworkStream + Send> {
+    fn from(s: T) -> Box<NetworkStream + Send> {
+        Box::new(s)
+    }
+}
+
 impl fmt::Debug for Box<NetworkStream + Send> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         fmt.pad("Box<NetworkStream>")
@@ -294,13 +300,12 @@ impl NetworkStream for HttpStream {
 }
 
 /// A connector that will produce HttpStreams.
-#[allow(missing_copy_implementations)]
-pub struct HttpConnector<'v>(pub Option<ContextVerifier<'v>>);
+pub struct HttpConnector(pub Option<ContextVerifier>);
 
 /// A method that can set verification methods on an SSL context
-pub type ContextVerifier<'v> = Box<FnMut(&mut SslContext) -> ()+'v>;
+pub type ContextVerifier = Box<FnMut(&mut SslContext) -> () + Send>;
 
-impl<'v> NetworkConnector for HttpConnector<'v> {
+impl NetworkConnector for HttpConnector {
     type Stream = HttpStream;
 
     fn connect(&mut self, host: &str, port: u16, scheme: &str) -> io::Result<HttpStream> {