nghttpx: Remove deprecated evbuffer_setcb, send WU before buffer gets empty

src/shrpx_downstream.cc

@@ -635,18 +635,6 @@ int Downstream::get_response_state() const
   return response_state_;
 }
 
-namespace {
-void body_buf_cb(evbuffer *body, size_t oldlen, size_t newlen, void *arg)
-{
-  Downstream *downstream = reinterpret_cast<Downstream*>(arg);
-  if(newlen == 0) {
-    if(downstream->resume_read(SHRPX_NO_BUFFER) == -1) {
-      DLOG(WARNING, downstream) << "Sending WINDOW_UPDATE failed";
-    }
-  }
-}
-} // namespace
-
 int Downstream::init_response_body_buf()
 {
   if(!response_body_buf_) {
@@ -654,7 +642,6 @@ int Downstream::init_response_body_buf()
     if(response_body_buf_ == nullptr) {
       DIE();
     }
-    evbuffer_setcb(response_body_buf_, body_buf_cb, this);
   }
   return 0;
 }

src/shrpx_http2_downstream_connection.cc

@@ -92,7 +92,6 @@ int Http2DownstreamConnection::init_request_body_buf()
     if(request_body_buf_ == nullptr) {
       return -1;
     }
-    evbuffer_setcb(request_body_buf_, nullptr, this);
   }
   return 0;
 }
@@ -212,6 +211,14 @@ ssize_t http2_data_read_callback(nghttp2_session *session,
         }
       }
     } else {
+      // Send WINDOW_UPDATE before buffer is empty to avoid delay
+      // because of RTT.
+      if(!downstream->get_output_buffer_full() &&
+         downstream->get_upstream()->resume_read(SHRPX_NO_BUFFER,
+                                                 downstream) == -1) {
+        // In this case, downstream may be deleted.
+        return NGHTTP2_ERR_DEFERRED;
+      }
       break;
     }
   }

src/shrpx_http2_upstream.cc

@@ -902,6 +902,13 @@ ssize_t downstream_data_read_callback(nghttp2_session *session,
                            (downstream->get_response_rst_stream_error_code()));
     }
   }
+  // Send WINDOW_UPDATE before buffer is empty to avoid delay because
+  // of RTT.
+  if(*eof != 1 &&
+     evbuffer_get_length(body) < SHRPX_HTTP2_UPSTREAM_OUTPUT_UPPER_THRES &&
+     downstream->resume_read(SHRPX_NO_BUFFER) != 0) {
+    DLOG(WARNING, downstream) << "Sending WINDOW_UPDATE failed";
+  }
   if(nread == 0 && *eof != 1) {
     return NGHTTP2_ERR_DEFERRED;
   }

src/shrpx_http_downstream_connection.cc

@@ -457,6 +457,10 @@ int htp_msg_completecb(http_parser *htp)
 {
   auto downstream = reinterpret_cast<Downstream*>(htp->data);
   downstream->set_response_state(Downstream::MSG_COMPLETE);
+  // Block reading another response message from (broken?)
+  // server. This callback is not called if the connection is
+  // tunneled.
+  downstream->pause_read(SHRPX_MSG_BLOCK);
   return downstream->get_upstream()->on_downstream_body_complete(downstream);
 }
 } // namespace