feat(client): Make client an optional feature

cc #2223

BREAKING CHANGE: The HTTP client of hyper is now an optional feature. To
  enable the client, add `features = ["client"]` to the dependency in
  your `Cargo.toml`.

Author: seanmonstar

Cargo.toml

@@ -74,11 +74,12 @@ pnet = "0.25.0"
 default = [
     "runtime",
     "stream",
-
+    "client",
     "http1",
     "http2",
 ]
 full = [
+    "client",
     "http1",
     "http2",
     "stream",
@@ -99,6 +100,8 @@ tcp = [
 http1 = []
 http2 = ["h2"]
 
+client = []
+
 # `impl Stream` for things
 stream = []
 

src/body/body.rs

@@ -6,6 +6,7 @@ use std::fmt;
 use bytes::Bytes;
 use futures_channel::mpsc;
 #[cfg(any(feature = "http1", feature = "http2"))]
+#[cfg(feature = "client")]
 use futures_channel::oneshot;
 use futures_core::Stream; // for mpsc::Receiver
 #[cfg(feature = "stream")]
@@ -18,6 +19,7 @@ use super::DecodedLength;
 use crate::common::sync_wrapper::SyncWrapper;
 use crate::common::{task, watch, Pin, Poll};
 #[cfg(any(feature = "http1", feature = "http2"))]
+#[cfg(feature = "client")]
 use crate::common::{Future, Never};
 #[cfg(feature = "http2")]
 use crate::proto::h2::ping;
@@ -72,16 +74,19 @@ struct Extra {
 }
 
 #[cfg(any(feature = "http1", feature = "http2"))]
+#[cfg(feature = "client")]
 type DelayEofUntil = oneshot::Receiver<Never>;
 
 enum DelayEof {
     /// Initial state, stream hasn't seen EOF yet.
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     NotEof(DelayEofUntil),
     /// Transitions to this state once we've seen `poll` try to
     /// return EOF (`None`). This future is then polled, and
     /// when it completes, the Body finally returns EOF (`None`).
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     Eof(DelayEofUntil),
 }
 
@@ -219,6 +224,7 @@ impl Body {
     }
 
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     pub(crate) fn delayed_eof(&mut self, fut: DelayEofUntil) {
         self.extra_mut().delayed_eof = Some(DelayEof::NotEof(fut));
     }
@@ -242,6 +248,7 @@ impl Body {
     fn poll_eof(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<crate::Result<Bytes>>> {
         match self.take_delayed_eof() {
             #[cfg(any(feature = "http1", feature = "http2"))]
+            #[cfg(feature = "client")]
             Some(DelayEof::NotEof(mut delay)) => match self.poll_inner(cx) {
                 ok @ Poll::Ready(Some(Ok(..))) | ok @ Poll::Pending => {
                     self.extra_mut().delayed_eof = Some(DelayEof::NotEof(delay));
@@ -258,6 +265,7 @@ impl Body {
                 Poll::Ready(Some(Err(e))) => Poll::Ready(Some(Err(e))),
             },
             #[cfg(any(feature = "http1", feature = "http2"))]
+            #[cfg(feature = "client")]
             Some(DelayEof::Eof(mut delay)) => match Pin::new(&mut delay).poll(cx) {
                 Poll::Ready(Ok(never)) => match never {},
                 Poll::Pending => {
@@ -266,7 +274,10 @@ impl Body {
                 }
                 Poll::Ready(Err(_done)) => Poll::Ready(None),
             },
-            #[cfg(not(any(feature = "http1", feature = "http2")))]
+            #[cfg(any(
+                not(any(feature = "http1", feature = "http2")),
+                not(feature = "client")
+            ))]
             Some(delay_eof) => match delay_eof {},
             None => self.poll_inner(cx),
         }

src/cfg.rs

@@ -1,37 +1,50 @@
-macro_rules! cfg_any_http {
-    ($($item:item)*) => {
+macro_rules! cfg_feature {
+    (
+        #![$meta:meta]
+        $($item:item)*
+    ) => {
         $(
-            #[cfg(any(
-                feature = "http1",
-                feature = "http2",
-            ))]
-            #[cfg_attr(docsrs, doc(cfg(any(
-                feature = "http1",
-                feature = "http2",
-            ))))]
+            #[cfg($meta)]
+            #[cfg_attr(docsrs, doc(cfg($meta)))]
             $item
         )*
     }
 }
 
+macro_rules! cfg_any_http {
+    ($($item:item)*) => {
+        cfg_feature! {
+            #![any(feature = "http1", feature = "http2")]
+            $($item)*
+        }
+    }
+}
+
 cfg_any_http! {
     macro_rules! cfg_http1 {
         ($($item:item)*) => {
-            $(
-                #[cfg(feature = "http1")]
-                #[cfg_attr(docsrs, doc(cfg(feature = "http1")))]
-                $item
-            )*
+            cfg_feature! {
+                #![feature = "http1"]
+                $($item)*
+            }
         }
     }
 
     macro_rules! cfg_http2 {
         ($($item:item)*) => {
-            $(
-                #[cfg(feature = "http2")]
-                #[cfg_attr(docsrs, doc(cfg(feature = "http2")))]
-                $item
-            )*
+            cfg_feature! {
+                #![feature = "http2"]
+                $($item)*
+            }
+        }
+    }
+
+    macro_rules! cfg_client {
+        ($($item:item)*) => {
+            cfg_feature! {
+                #![feature = "client"]
+                $($item)*
+            }
         }
     }
 }

src/client/conn.rs

@@ -25,7 +25,7 @@ use tower_service::Service;
 
 use super::dispatch;
 use crate::body::HttpBody;
-use crate::common::{task, BoxSendFuture, Exec, Future, Pin, Poll};
+use crate::common::{task, exec::{BoxSendFuture, Exec}, Future, Pin, Poll};
 use crate::proto;
 use crate::rt::Executor;
 #[cfg(feature = "http1")]

src/client/mod.rs

@@ -62,7 +62,7 @@ use http::{Method, Request, Response, Uri, Version};
 use self::connect::{sealed::Connect, Alpn, Connected, Connection};
 use self::pool::{Key as PoolKey, Pool, Poolable, Pooled, Reservation};
 use crate::body::{Body, HttpBody};
-use crate::common::{lazy as hyper_lazy, task, BoxSendFuture, Future, Lazy, Pin, Poll};
+use crate::common::{lazy as hyper_lazy, task, exec::BoxSendFuture, Future, Lazy, Pin, Poll};
 use crate::rt::Executor;
 
 #[cfg(feature = "tcp")]

src/client/pool.rs

@@ -11,7 +11,7 @@ use futures_channel::oneshot;
 use tokio::time::{Duration, Instant, Interval};
 
 use super::Ver;
-use crate::common::{task, Exec, Future, Pin, Poll, Unpin};
+use crate::common::{task, exec::Exec, Future, Pin, Poll, Unpin};
 
 // FIXME: allow() required due to `impl Trait` leaking types to this lint
 #[allow(missing_debug_implementations)]
@@ -777,7 +777,7 @@ mod tests {
     use std::time::Duration;
 
     use super::{Connecting, Key, Pool, Poolable, Reservation, WeakOpt};
-    use crate::common::{task, Exec, Future, Pin};
+    use crate::common::{task, exec::Exec, Future, Pin};
 
     /// Test unique reservations.
     #[derive(Debug, PartialEq, Eq)]

src/common/mod.rs

@@ -16,16 +16,18 @@ pub(crate) mod drain;
 pub(crate) mod exec;
 pub(crate) mod io;
 #[cfg(any(feature = "http1", feature = "http2"))]
+#[cfg(feature = "client")]
 mod lazy;
 mod never;
 #[cfg(feature = "stream")]
 pub(crate) mod sync_wrapper;
 pub(crate) mod task;
 pub(crate) mod watch;
 
+//#[cfg(any(feature = "http1", feature = "http2"))]
+//pub(crate) use self::exec::{BoxSendFuture, Exec};
 #[cfg(any(feature = "http1", feature = "http2"))]
-pub(crate) use self::exec::{BoxSendFuture, Exec};
-#[cfg(any(feature = "http1", feature = "http2"))]
+#[cfg(feature = "client")]
 pub(crate) use self::lazy::{lazy, Started as Lazy};
 pub use self::never::Never;
 pub(crate) use self::task::Poll;

src/error.rs

@@ -88,15 +88,18 @@ pub(crate) enum User {
     UnexpectedHeader,
     /// User tried to create a Request with bad version.
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     UnsupportedVersion,
     /// User tried to create a CONNECT Request with the Client.
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     UnsupportedRequestMethod,
     /// User tried to respond with a 1xx (not 101) response code.
     #[cfg(feature = "http1")]
     UnsupportedStatusCode,
     /// User tried to send a Request with Client with non-absolute URI.
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     AbsoluteUriRequired,
 
     /// User tried polling for an upgrade that doesn't exist.
@@ -241,6 +244,7 @@ impl Error {
     }
 
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     pub(crate) fn new_connect<E: Into<Cause>>(cause: E) -> Error {
         Error::new(Kind::Connect).with(cause)
     }
@@ -273,11 +277,13 @@ impl Error {
     }
 
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     pub(crate) fn new_user_unsupported_version() -> Error {
         Error::new_user(User::UnsupportedVersion)
     }
 
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     pub(crate) fn new_user_unsupported_request_method() -> Error {
         Error::new_user(User::UnsupportedRequestMethod)
     }
@@ -288,6 +294,7 @@ impl Error {
     }
 
     #[cfg(any(feature = "http1", feature = "http2"))]
+    #[cfg(feature = "client")]
     pub(crate) fn new_user_absolute_uri_required() -> Error {
         Error::new_user(User::AbsoluteUriRequired)
     }
@@ -371,14 +378,17 @@ impl Error {
             #[cfg(feature = "http1")]
             Kind::User(User::UnexpectedHeader) => "user sent unexpected header",
             #[cfg(any(feature = "http1", feature = "http2"))]
+            #[cfg(feature = "client")]
             Kind::User(User::UnsupportedVersion) => "request has unsupported HTTP version",
             #[cfg(any(feature = "http1", feature = "http2"))]
+            #[cfg(feature = "client")]
             Kind::User(User::UnsupportedRequestMethod) => "request has unsupported HTTP method",
             #[cfg(feature = "http1")]
             Kind::User(User::UnsupportedStatusCode) => {
                 "response has 1xx status code, not supported by server"
             }
             #[cfg(any(feature = "http1", feature = "http2"))]
+            #[cfg(feature = "client")]
             Kind::User(User::AbsoluteUriRequired) => "client requires absolute-form URIs",
             Kind::User(User::NoUpgrade) => "no upgrade available",
             #[cfg(feature = "http1")]

src/headers.rs

@@ -3,7 +3,8 @@ use bytes::BytesMut;
 use http::header::CONTENT_LENGTH;
 use http::header::{HeaderValue, ValueIter};
 #[cfg(feature = "http2")]
-use http::method::Method;
+#[cfg(feature = "client")]
+use http::Method;
 use http::HeaderMap;
 
 #[cfg(feature = "http1")]
@@ -65,6 +66,7 @@ pub fn content_length_parse_all_values(values: ValueIter<'_, HeaderValue>) -> Op
 }
 
 #[cfg(feature = "http2")]
+#[cfg(feature = "client")]
 pub fn method_has_defined_payload_semantics(method: &Method) -> bool {
     match *method {
         Method::GET | Method::HEAD | Method::DELETE | Method::CONNECT => false,

src/lib.rs

@@ -71,9 +71,14 @@ pub mod upgrade;
 cfg_any_http! {
     mod headers;
     mod proto;
-    pub mod client;
     pub mod server;
 
-    pub use crate::client::Client;
     pub use crate::server::Server;
 }
+
+cfg_feature! {
+    #![all(feature = "client", any(feature = "http1", feature = "http2"))]
+
+    pub mod client;
+    pub use crate::client::Client;
+}