aggregate WINDOW_UPDATE frames until change is over 50% available

tests/flow_control.rs

@@ -49,6 +49,161 @@ fn send_data_without_requesting_capacity() {
     h2.wait().unwrap();
 }
 
+#[test]
+fn release_capacity_sends_window_update() {
+    let _ = ::env_logger::init();
+
+    let payload = vec![0; 65_535];
+
+    let mock = mock_io::Builder::new()
+        .handshake()
+        .write(&[
+            // GET /
+            0, 0, 16, 1, 5, 0, 0, 0, 1, 130, 135, 65, 139, 157, 41,
+            172, 75, 143, 168, 233, 25, 151, 33, 233, 132,
+        ])
+        .write(frames::SETTINGS_ACK)
+        // Read response
+        .read(&[0, 0, 1, 1, 4, 0, 0, 0, 1, 0x88])
+        .read(&[
+            // DATA
+            0, 64, 0, 0, 0, 0, 0, 0, 1,
+        ])
+        .read(&payload[0..16_384])
+        .read(&[
+            // DATA
+            0, 64, 0, 0, 0, 0, 0, 0, 1,
+        ])
+        .read(&payload[16_384..16_384*2])
+        .read(&[
+            // DATA
+            0, 64, 0, 0, 0, 0, 0, 0, 1,
+        ])
+        .read(&payload[16_384*2..16_384*3])
+        .write(&[0, 0, 4, 8, 0, 0, 0, 0, 0, 0, 0, 128, 0])
+        .write(&[0, 0, 4, 8, 0, 0, 0, 0, 1, 0, 0, 128, 0])
+        .read(&[
+            // DATA
+            0, 63, 255, 0, 1, 0, 0, 0, 1,
+        ])
+        .read(&payload[16_384*3..16_384*4 - 1])
+
+        // we send a 2nd stream in order to test the window update is
+        // is actually written to the socket
+        .write(&[
+            // GET /
+            0, 0, 4, 1, 5, 0, 0, 0, 3, 130, 135, 190, 132,
+        ])
+        .read(&[0, 0, 1, 1, 5, 0, 0, 0, 3, 0x88])
+        .build();
+
+    let mut h2 = Client::handshake(mock)
+        .wait().unwrap();
+
+    let request = Request::builder()
+        .method(Method::GET)
+        .uri("https://http2.akamai.com/")
+        .body(()).unwrap();
+
+    let mut stream = h2.request(request, true).unwrap();
+
+    // Get the response
+    let resp = h2.run(poll_fn(|| stream.poll_response())).unwrap();
+    assert_eq!(resp.status(), StatusCode::OK);
+
+    // read some body to use up window size to below half
+    let mut body = resp.into_parts().1;
+    let buf = h2.run(poll_fn(|| body.poll())).unwrap().unwrap();
+    assert_eq!(buf.len(), 16_384);
+    let buf = h2.run(poll_fn(|| body.poll())).unwrap().unwrap();
+    assert_eq!(buf.len(), 16_384);
+    let buf = h2.run(poll_fn(|| body.poll())).unwrap().unwrap();
+    assert_eq!(buf.len(), 16_384);
+
+    // release some capacity to send a window_update
+    body.release_capacity(buf.len() * 2).unwrap();
+
+    let buf = h2.run(poll_fn(|| body.poll())).unwrap().unwrap();
+    assert_eq!(buf.len(), 16_383);
+
+
+    // send a 2nd stream to force flushing of window updates
+    let request = Request::builder()
+        .method(Method::GET)
+        .uri("https://http2.akamai.com/")
+        .body(()).unwrap();
+    let mut stream = h2.request(request, true).unwrap();
+    let resp = h2.run(poll_fn(|| stream.poll_response())).unwrap();
+    assert_eq!(resp.status(), StatusCode::OK);
+
+    h2.wait().unwrap();
+}
+
+#[test]
+fn release_capacity_of_small_amount_does_not_send_window_update() {
+    let _ = ::env_logger::init();
+
+    let payload = [0; 16];
+
+    let mock = mock_io::Builder::new()
+        .handshake()
+        .write(&[
+            // GET /
+            0, 0, 16, 1, 5, 0, 0, 0, 1, 130, 135, 65, 139, 157, 41,
+            172, 75, 143, 168, 233, 25, 151, 33, 233, 132,
+        ])
+        .write(frames::SETTINGS_ACK)
+        // Read response
+        .read(&[0, 0, 1, 1, 4, 0, 0, 0, 1, 0x88])
+        .read(&[
+            // DATA
+            0, 0, 16, 0, 1, 0, 0, 0, 1,
+        ])
+        .read(&payload[..])
+        // write() or WINDOW_UPDATE purposefully excluded
+
+        // we send a 2nd stream in order to test the window update is
+        // is actually written to the socket
+        .write(&[
+            // GET /
+            0, 0, 4, 1, 5, 0, 0, 0, 3, 130, 135, 190, 132,
+        ])
+        .read(&[0, 0, 1, 1, 5, 0, 0, 0, 3, 0x88])
+        .build();
+
+    let mut h2 = Client::handshake(mock)
+        .wait().unwrap();
+
+    let request = Request::builder()
+        .method(Method::GET)
+        .uri("https://http2.akamai.com/")
+        .body(()).unwrap();
+
+    let mut stream = h2.request(request, true).unwrap();
+
+    // Get the response
+    let resp = h2.run(poll_fn(|| stream.poll_response())).unwrap();
+    assert_eq!(resp.status(), StatusCode::OK);
+
+    let mut body = resp.into_parts().1;
+    let buf = h2.run(poll_fn(|| body.poll())).unwrap().unwrap();
+
+    // release some capacity to send a window_update
+    body.release_capacity(buf.len()).unwrap();
+
+    // send a 2nd stream to force flushing of window updates
+    let request = Request::builder()
+        .method(Method::GET)
+        .uri("https://http2.akamai.com/")
+        .body(()).unwrap();
+    let mut stream = h2.request(request, true).unwrap();
+    let resp = h2.run(poll_fn(|| stream.poll_response())).unwrap();
+    assert_eq!(resp.status(), StatusCode::OK);
+
+
+    h2.wait().unwrap();
+}
+
 #[test]
 #[ignore]
 fn expand_window_sends_window_update() {