Don't wait for a full buffer when reading TCP

libnative erroneously would attempt to fill the entire buffer in a call to
`read` before returning, when rather it should return immediately because
there's not guaranteed to be any data that will ever be received again.

Close #11328

1 files changed, 21 insertions, 0 deletions

diff --git a/src/libstd/io/net/tcp.rs b/src/libstd/io/net/tcp.rs
index 52cca7f622b..c2a70e0120d 100644
--- a/src/libstd/io/net/tcp.rs
+++ b/src/libstd/io/net/tcp.rs
@@ -589,4 +589,25 @@ mod test {
         //peer_name(next_test_ip6());
         socket_name(next_test_ip6());
     })
+
+    iotest!(fn partial_read() {
+        let addr = next_test_ip4();
+        let (p, c) = Chan::new();
+        do spawn {
+            let mut srv = TcpListener::bind(addr).listen();
+            c.send(());
+            let mut cl = srv.accept().unwrap();
+            cl.write([10]);
+            let mut b = [0];
+            cl.read(b);
+            c.send(());
+        }
+
+        p.recv();
+        let mut c = TcpStream::connect(addr).unwrap();
+        let mut b = [0, ..10];
+        assert_eq!(c.read(b), Some(1));
+        c.write([1]);
+        p.recv();
+    })
 }