refactor(server): simplify server cfgs

`server.rs` is currently littered with `cfg`s for `http1` or `http2`,
since the majority of server behaviour is only available with either one
of those feature flags active. This is hard to maintain and confusing to
read, so this commit extracts the two implementations into their own
files, since there is very little benefit in sharing code between the
two.

src/server/conn.rs

@@ -48,6 +48,7 @@
     not(all(feature = "http1", feature = "http2"))
 ))]
 use std::marker::PhantomData;
+#[cfg(all(any(feature = "http1", feature = "http2"), feature = "runtime"))]
 use std::time::Duration;
 
 #[cfg(feature = "http2")]

src/server/mod.rs

@@ -149,7 +149,6 @@
 
 pub mod accept;
 pub mod conn;
-pub(crate) mod server;
 #[cfg(feature = "tcp")]
 mod tcp;
 
@@ -158,7 +157,15 @@ pub use self::server::Server;
 cfg_feature! {
     #![any(feature = "http1", feature = "http2")]
 
+    pub(crate) mod server;
     pub use self::server::Builder;
 
     mod shutdown;
 }
+
+cfg_feature! {
+    #![not(any(feature = "http1", feature = "http2"))]
+
+    mod server_stub;
+    use server_stub as server;
+}

src/server/server.rs

@@ -1,36 +1,29 @@
+use std::error::Error as StdError;
 use std::fmt;
 #[cfg(feature = "tcp")]
 use std::net::{SocketAddr, TcpListener as StdTcpListener};
 #[cfg(any(feature = "tcp", feature = "http1"))]
 use std::time::Duration;
 
-#[cfg(all(feature = "tcp", any(feature = "http1", feature = "http2")))]
+use pin_project_lite::pin_project;
+use tokio::io::{AsyncRead, AsyncWrite};
+use tracing::trace;
+
+use super::accept::Accept;
+#[cfg(all(feature = "tcp"))]
 use super::tcp::AddrIncoming;
+use crate::body::{Body, HttpBody};
 use crate::common::exec::Exec;
+use crate::common::exec::{ConnStreamExec, NewSvcExec};
+use crate::common::{task, Future, Pin, Poll, Unpin};
+// Renamed `Http` as `Http_` for now so that people upgrading don't see an
+// error that `hyper::server::Http` is private...
+use super::conn::{Connection, Http as Http_, UpgradeableConnection};
+use super::shutdown::{Graceful, GracefulWatcher};
+use crate::service::{HttpService, MakeServiceRef};
 
-cfg_feature! {
+use self::new_svc::NewSvcTask;
-    #![any(feature = "http1", feature = "http2")]
 
-    use std::error::Error as StdError;
-
-    use pin_project_lite::pin_project;
-    use tokio::io::{AsyncRead, AsyncWrite};
-    use tracing::trace;
-
-    use super::accept::Accept;
-    use crate::body::{Body, HttpBody};
-    use crate::common::{task, Future, Pin, Poll, Unpin};
-    use crate::common::exec::{ConnStreamExec, NewSvcExec};
-    // Renamed `Http` as `Http_` for now so that people upgrading don't see an
-    // error that `hyper::server::Http` is private...
-    use super::conn::{Connection, Http as Http_, UpgradeableConnection};
-    use super::shutdown::{Graceful, GracefulWatcher};
-    use crate::service::{HttpService, MakeServiceRef};
-
-    use self::new_svc::NewSvcTask;
-}
-
-#[cfg(any(feature = "http1", feature = "http2"))]
 pin_project! {
     /// A listening HTTP server that accepts connections in both HTTP1 and HTTP2 by default.
     ///
@@ -46,17 +39,8 @@ pin_project! {
     }
 }
 
-/// A listening HTTP server that accepts connections in both HTTP1 and HTTP2 by default.
-///
-/// Needs at least one of the `http1` and `http2` features to be activated to actually be useful.
-#[cfg(not(any(feature = "http1", feature = "http2")))]
-pub struct Server<I, S, E = Exec> {
-    _marker: std::marker::PhantomData<(I, S, E)>,
-}
-
 /// A builder for a [`Server`](Server).
 #[derive(Debug)]
-#[cfg(any(feature = "http1", feature = "http2"))]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "http1", feature = "http2"))))]
 pub struct Builder<I, E = Exec> {
     incoming: I,
@@ -65,7 +49,6 @@ pub struct Builder<I, E = Exec> {
 
 // ===== impl Server =====
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "http1", feature = "http2"))))]
 impl<I> Server<I, ()> {
     /// Starts a [`Builder`](Builder) with the provided incoming stream.
@@ -77,10 +60,12 @@ impl<I> Server<I, ()> {
     }
 }
 
-cfg_feature! {
+#[cfg(feature = "tcp")]
-    #![all(feature = "tcp", any(feature = "http1", feature = "http2"))]
+#[cfg_attr(
-
+    docsrs,
-    impl Server<AddrIncoming, ()> {
+    doc(cfg(all(feature = "tcp", any(feature = "http1", feature = "http2"))))
+)]
+impl Server<AddrIncoming, ()> {
     /// Binds to the provided address, and returns a [`Builder`](Builder).
     ///
     /// # Panics
@@ -103,21 +88,20 @@ cfg_feature! {
     pub fn from_tcp(listener: StdTcpListener) -> Result<Builder<AddrIncoming>, crate::Error> {
         AddrIncoming::from_std(listener).map(Server::builder)
     }
-    }
 }
 
-cfg_feature! {
+#[cfg(feature = "tcp")]
-    #![all(feature = "tcp", any(feature = "http1", feature = "http2"))]
+#[cfg_attr(
-
+    docsrs,
-    impl<S, E> Server<AddrIncoming, S, E> {
+    doc(cfg(all(feature = "tcp", any(feature = "http1", feature = "http2"))))
+)]
+impl<S, E> Server<AddrIncoming, S, E> {
     /// Returns the local address that this server is bound to.
     pub fn local_addr(&self) -> SocketAddr {
         self.incoming.local_addr()
     }
-    }
 }
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "http1", feature = "http2"))))]
 impl<I, IO, IE, S, E, B> Server<I, S, E>
 where
@@ -220,7 +204,6 @@ where
     }
 }
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "http1", feature = "http2"))))]
 impl<I, IO, IE, S, B, E> Future for Server<I, S, E>
 where
@@ -244,7 +227,6 @@ where
 impl<I: fmt::Debug, S: fmt::Debug> fmt::Debug for Server<I, S> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut st = f.debug_struct("Server");
-        #[cfg(any(feature = "http1", feature = "http2"))]
         st.field("listener", &self.incoming);
         st.finish()
     }
@@ -252,7 +234,6 @@ impl<I: fmt::Debug, S: fmt::Debug> fmt::Debug for Server<I, S> {
 
 // ===== impl Builder =====
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 #[cfg_attr(docsrs, doc(cfg(any(feature = "http1", feature = "http2"))))]
 impl<I, E> Builder<I, E> {
     /// Start a new builder, wrapping an incoming stream and low-level options.
@@ -572,7 +553,11 @@ impl<I, E> Builder<I, E> {
     }
 }
 
-#[cfg(all(feature = "tcp", any(feature = "http1", feature = "http2")))]
+#[cfg(feature = "tcp")]
+#[cfg_attr(
+    docsrs,
+    doc(cfg(all(feature = "tcp", any(feature = "http1", feature = "http2"))))
+)]
 impl<E> Builder<AddrIncoming, E> {
     /// Set whether TCP keepalive messages are enabled on accepted connections.
     ///
@@ -619,7 +604,6 @@ impl<E> Builder<AddrIncoming, E> {
 // The `Server::with_graceful_shutdown` needs to keep track of all active
 // connections, and signal that they start to shutdown when prompted, so
 // it has a `GracefulWatcher` implementation to do that.
-#[cfg(any(feature = "http1", feature = "http2"))]
 pub trait Watcher<I, S: HttpService<Body>, E>: Clone {
     type Future: Future<Output = crate::Result<()>>;
 
@@ -628,10 +612,8 @@ pub trait Watcher<I, S: HttpService<Body>, E>: Clone {
 
 #[allow(missing_debug_implementations)]
 #[derive(Copy, Clone)]
-#[cfg(any(feature = "http1", feature = "http2"))]
 pub struct NoopWatcher;
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 impl<I, S, E> Watcher<I, S, E> for NoopWatcher
 where
     I: AsyncRead + AsyncWrite + Unpin + Send + 'static,
@@ -647,7 +629,6 @@ where
     }
 }
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 // used by exec.rs
 pub(crate) mod new_svc {
     use std::error::Error as StdError;
@@ -759,7 +740,6 @@ pub(crate) mod new_svc {
     }
 }
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 pin_project! {
     /// A future building a new `Service` to a `Connection`.
     ///
@@ -776,7 +756,6 @@ pin_project! {
     }
 }
 
-#[cfg(any(feature = "http1", feature = "http2"))]
 impl<I, F, S, FE, E, B> Future for Connecting<I, F, E>
 where
     I: AsyncRead + AsyncWrite + Unpin,

src/server/server_stub.rs

@@ -0,0 +1,16 @@
+use std::fmt;
+
+use crate::common::exec::Exec;
+
+/// A listening HTTP server that accepts connections in both HTTP1 and HTTP2 by default.
+///
+/// Needs at least one of the `http1` and `http2` features to be activated to actually be useful.
+pub struct Server<I, S, E = Exec> {
+    _marker: std::marker::PhantomData<(I, S, E)>,
+}
+
+impl<I: fmt::Debug, S: fmt::Debug> fmt::Debug for Server<I, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Server").finish()
+    }
+}