fix(http1): reduce closed connections when body is dropped

If a user makes use of `Body::is_end_stream` to optimize so as to not
need to do make a final poll just to receive `None`, previously the
connection would not have progressed its reading state to a finished
body, and so the connection would be closed.

Now, upon reading any chunk, the connection state will check if it
can know that the body would be finished, and progresses to a body
finished state sooner.

The integration tests were amplified by adding a naive hyper proxy
as a secondary test, which happens to make use of that optimization,
and thus caught the issue.

tests/support/mod.rs

@@ -2,6 +2,13 @@ pub extern crate futures;
 pub extern crate hyper;
 pub extern crate tokio;
 
+use std::sync::{Arc, Mutex, atomic::{AtomicUsize, Ordering}};
+use std::time::Duration;
+
+use hyper::{Body, Client, Request, Response, Server, Version};
+use hyper::client::HttpConnector;
+use hyper::service::service_fn;
+
 pub use std::net::SocketAddr;
 pub use self::futures::{future, Future, Stream};
 pub use self::futures::sync::oneshot;
@@ -44,6 +51,16 @@ macro_rules! t {
                 ));
             }
 
+            __run_test(__TestConfig {
+                client_version: 2,
+                client_msgs: c.clone(),
+                server_version: 2,
+                server_msgs: s.clone(),
+                parallel: true,
+                connections: 1,
+                proxy: false,
+            });
+
             __run_test(__TestConfig {
                 client_version: 2,
                 client_msgs: c,
@@ -51,8 +68,8 @@ macro_rules! t {
                 server_msgs: s,
                 parallel: true,
                 connections: 1,
+                proxy: true,
             });
-
         }
     );
     (
@@ -104,6 +121,27 @@ macro_rules! t {
                 server_msgs: s.clone(),
                 parallel: false,
                 connections: 1,
+                proxy: false,
+            });
+
+            __run_test(__TestConfig {
+                client_version: 2,
+                client_msgs: c.clone(),
+                server_version: 2,
+                server_msgs: s.clone(),
+                parallel: false,
+                connections: 1,
+                proxy: false,
+            });
+
+            __run_test(__TestConfig {
+                client_version: 1,
+                client_msgs: c.clone(),
+                server_version: 1,
+                server_msgs: s.clone(),
+                parallel: false,
+                connections: 1,
+                proxy: true,
             });
 
             __run_test(__TestConfig {
@@ -113,6 +151,7 @@ macro_rules! t {
                 server_msgs: s,
                 parallel: false,
                 connections: 1,
+                proxy: true,
             });
         }
     );
@@ -185,14 +224,11 @@ pub struct __TestConfig {
 
     pub parallel: bool,
     pub connections: usize,
+    pub proxy: bool,
 }
 
 pub fn __run_test(cfg: __TestConfig) {
     extern crate pretty_env_logger;
-    use hyper::{Body, Client, Request, Response, Version};
-    use hyper::client::HttpConnector;
-    use std::sync::{Arc, Mutex};
-    use std::time::Duration;
     let _ = pretty_env_logger::try_init();
     let mut rt = Runtime::new().expect("new rt");
 
@@ -254,31 +290,39 @@ pub fn __run_test(cfg: __TestConfig) {
         )
         .expect("serve_addr");
 
-    let addr = serve.incoming_ref().local_addr();
-    let (shutdown_tx, shutdown_rx) = oneshot::channel();
-    let (success_tx, success_rx) = oneshot::channel();
+    let mut addr = serve.incoming_ref().local_addr();
     let expected_connections = cfg.connections;
     let server = serve
         .fold(0, move |cnt, connecting| {
+            let cnt = cnt + 1;
+            assert!(
+                cnt <= expected_connections,
+                "server expected {} connections, received {}",
+                expected_connections,
+                cnt
+            );
             let fut = connecting
                 .map_err(|never| -> hyper::Error { match never {} })
                 .flatten()
                 .map_err(|e| panic!("server connection error: {}", e));
             ::tokio::spawn(fut);
-            Ok::<_, hyper::Error>(cnt + 1)
+            Ok::<_, hyper::Error>(cnt)
         })
-        .map(move |cnt| {
-            assert_eq!(cnt, expected_connections);
-        })
-        .map_err(|e| panic!("serve error: {}", e))
-        .select2(shutdown_rx)
-        .map(move |_| {
-            let _ = success_tx.send(());
-        })
-        .map_err(|_| panic!("shutdown not ok"));
+        .map(|_| ())
+        .map_err(|e| panic!("serve error: {}", e));
 
     rt.spawn(server);
 
+    if cfg.proxy {
+        let (proxy_addr, proxy) = naive_proxy(ProxyConfig {
+            connections: cfg.connections,
+            dst: addr,
+            version: cfg.server_version,
+        });
+        rt.spawn(proxy);
+        addr = proxy_addr;
+    }
+
 
     let make_request = Arc::new(move |client: &Client<HttpConnector>, creq: __CReq, cres: __CRes| {
         let uri = format!("http://{}{}", addr, creq.uri);
@@ -335,12 +379,41 @@ pub fn __run_test(cfg: __TestConfig) {
         Box::new(client_futures.map(|_| ()))
     };
 
-    let client_futures = client_futures.map(move |_| {
-        let _ = shutdown_tx.send(());
-    });
-    rt.spawn(client_futures);
-    rt.block_on(success_rx
-        .map_err(|_| "something panicked"))
+    let client_futures = client_futures.map(|_| ());
+    rt.block_on(client_futures)
         .expect("shutdown succeeded");
 }
 
+struct ProxyConfig {
+    connections: usize,
+    dst: SocketAddr,
+    version: usize,
+}
+
+fn naive_proxy(cfg: ProxyConfig) -> (SocketAddr, impl Future<Item = (), Error = ()>) {
+    let client = Client::builder()
+        .keep_alive_timeout(Duration::from_secs(10))
+        .http2_only(cfg.version == 2)
+        .build_http::<Body>();
+
+    let dst_addr = cfg.dst;
+    let max_connections = cfg.connections;
+    let counter = AtomicUsize::new(0);
+
+    let srv = Server::bind(&([127, 0, 0, 1], 0).into())
+        .serve(move || {
+            let prev = counter.fetch_add(1, Ordering::Relaxed);
+            assert!(max_connections >= prev + 1, "proxy max connections");
+            let client = client.clone();
+            service_fn(move |mut req| {
+                let uri = format!("http://{}{}", dst_addr, req.uri().path())
+                    .parse()
+                    .expect("proxy new uri parse");
+                *req.uri_mut() = uri;
+                client.request(req)
+            })
+
+        });
+    let proxy_addr = srv.local_addr();
+    (proxy_addr, srv.map_err(|err| panic!("proxy error: {}", err)))
+}