1 files changed, 87 insertions, 41 deletions

diff --git a/src/node_http2.cc b/src/node_http2.cc
index 0fec129373..7e32f7f14b 100644
--- a/src/node_http2.cc
+++ b/src/node_http2.cc
@@ -868,31 +868,51 @@ ssize_t Http2Session::OnCallbackPadding(size_t frameLen,
 // various callback functions. Each of these will typically result in a call
 // out to JavaScript so this particular function is rather hot and can be
 // quite expensive. This is a potential performance optimization target later.
-ssize_t Http2Session::Write(const uv_buf_t* bufs, size_t nbufs) {
-  size_t total = 0;
-  // Note that nghttp2_session_mem_recv is a synchronous operation that
-  // will trigger a number of other callbacks. Those will, in turn have
+ssize_t Http2Session::ConsumeHTTP2Data() {
+  CHECK_NOT_NULL(stream_buf_.base);
+  CHECK_LT(stream_buf_offset_, stream_buf_.len);
+  size_t read_len = stream_buf_.len - stream_buf_offset_;
+
   // multiple side effects.
-  for (size_t n = 0; n < nbufs; n++) {
-    Debug(this, "receiving %d bytes [wants data? %d]",
-          bufs[n].len,
-          nghttp2_session_want_read(session_));
-    ssize_t ret =
-      nghttp2_session_mem_recv(session_,
-                               reinterpret_cast<uint8_t*>(bufs[n].base),
-                               bufs[n].len);
-    CHECK_NE(ret, NGHTTP2_ERR_NOMEM);
-
-    if (ret < 0)
-      return ret;
+  Debug(this, "receiving %d bytes [wants data? %d]",
+        read_len,
+        nghttp2_session_want_read(session_));
+  flags_ &= ~SESSION_STATE_NGHTTP2_RECV_PAUSED;
+  ssize_t ret =
+    nghttp2_session_mem_recv(session_,
+                             reinterpret_cast<uint8_t*>(stream_buf_.base) +
+                                 stream_buf_offset_,
+                             read_len);
+  CHECK_NE(ret, NGHTTP2_ERR_NOMEM);
 
-    total += ret;
+  if (flags_ & SESSION_STATE_NGHTTP2_RECV_PAUSED) {
+    CHECK_NE(flags_ & SESSION_STATE_READING_STOPPED, 0);
+
+    CHECK_GT(ret, 0);
+    CHECK_LE(static_cast<size_t>(ret), read_len);
+
+    if (static_cast<size_t>(ret) < read_len) {
+      // Mark the remainder of the data as available for later consumption.
+      stream_buf_offset_ += ret;
+      return ret;
+    }
   }
+
+  // We are done processing the current input chunk.
+  DecrementCurrentSessionMemory(stream_buf_.len);
+  stream_buf_offset_ = 0;
+  stream_buf_ab_.Reset();
+  stream_buf_allocation_.clear();
+  stream_buf_ = uv_buf_init(nullptr, 0);
+
+  if (ret < 0)
+    return ret;
+
   // Send any data that was queued up while processing the received data.
   if (!IsDestroyed()) {
     SendPendingData();
   }
-  return total;
+  return ret;
 }
 
 
@@ -1194,8 +1214,18 @@ int Http2Session::OnDataChunkReceived(nghttp2_session* handle,
       nghttp2_session_consume_stream(handle, id, avail);
     else
       stream->inbound_consumed_data_while_paused_ += avail;
+
+    // If we have a gathered a lot of data for output, try sending it now.
+    if (session->outgoing_length_ > 4096) session->SendPendingData();
   } while (len != 0);
 
+  // If we are currently waiting for a write operation to finish, we should
+  // tell nghttp2 that we want to wait before we process more input data.
+  if (session->flags_ & SESSION_STATE_WRITE_IN_PROGRESS) {
+    session->flags_ |= SESSION_STATE_NGHTTP2_RECV_PAUSED;
+    return NGHTTP2_ERR_PAUSE;
+  }
+
   return 0;
 }
 
@@ -1283,6 +1313,7 @@ void Http2StreamListener::OnStreamRead(ssize_t nread, const uv_buf_t& buf) {
   size_t offset = buf.base - session->stream_buf_.base;
 
   // Verify that the data offset is inside the current read buffer.
+  CHECK_GE(offset, session->stream_buf_offset_);
   CHECK_LE(offset, session->stream_buf_.len);
   CHECK_LE(offset + buf.len, session->stream_buf_.len);
 
@@ -1554,6 +1585,11 @@ void Http2Session::OnStreamAfterWrite(WriteWrap* w, int status) {
     stream_->ReadStart();
   }
 
+  // If there is more incoming data queued up, consume it.
+  if (stream_buf_offset_ > 0) {
+    ConsumeHTTP2Data();
+  }
+
   if (!(flags_ & SESSION_STATE_WRITE_SCHEDULED)) {
     // Schedule a new write if nghttp2 wants to send data.
     MaybeScheduleWrite();
@@ -1609,6 +1645,7 @@ void Http2Session::ClearOutgoing(int status) {
 
   if (outgoing_buffers_.size() > 0) {
     outgoing_storage_.clear();
+    outgoing_length_ = 0;
 
     std::vector<nghttp2_stream_write> current_outgoing_buffers_;
     current_outgoing_buffers_.swap(outgoing_buffers_);
@@ -1639,6 +1676,11 @@ void Http2Session::ClearOutgoing(int status) {
   }
 }
 
+void Http2Session::PushOutgoingBuffer(nghttp2_stream_write&& write) {
+  outgoing_length_ += write.buf.len;
+  outgoing_buffers_.emplace_back(std::move(write));
+}
+
 // Queue a given block of data for sending. This always creates a copy,
 // so it is used for the cases in which nghttp2 requests sending of a
 // small chunk of data.
@@ -1651,7 +1693,7 @@ void Http2Session::CopyDataIntoOutgoing(const uint8_t* src, size_t src_length) {
   // of the outgoing_buffers_ vector may invalidate the pointer.
   // The correct base pointers will be set later, before writing to the
   // underlying socket.
-  outgoing_buffers_.emplace_back(nghttp2_stream_write {
+  PushOutgoingBuffer(nghttp2_stream_write {
     uv_buf_init(nullptr, src_length)
   });
 }
@@ -1774,13 +1816,13 @@ int Http2Session::OnSendData(
     if (write.buf.len <= length) {
       // This write does not suffice by itself, so we can consume it completely.
       length -= write.buf.len;
-      session->outgoing_buffers_.emplace_back(std::move(write));
+      session->PushOutgoingBuffer(std::move(write));
       stream->queue_.pop();
       continue;
     }
 
     // Slice off `length` bytes of the first write in the queue.
-    session->outgoing_buffers_.emplace_back(nghttp2_stream_write {
+    session->PushOutgoingBuffer(nghttp2_stream_write {
       uv_buf_init(write.buf.base, length)
     });
     write.buf.base += length;
@@ -1790,7 +1832,7 @@ int Http2Session::OnSendData(
 
   if (frame->data.padlen > 0) {
     // Send padding if that was requested.
-    session->outgoing_buffers_.emplace_back(nghttp2_stream_write {
+    session->PushOutgoingBuffer(nghttp2_stream_write {
       uv_buf_init(const_cast<char*>(zero_bytes_256), frame->data.padlen - 1)
     });
   }
@@ -1827,8 +1869,6 @@ void Http2Session::OnStreamRead(ssize_t nread, const uv_buf_t& buf_) {
   Http2Scope h2scope(this);
   CHECK_NOT_NULL(stream_);
   Debug(this, "receiving %d bytes", nread);
-  CHECK_EQ(stream_buf_allocation_.size(), 0);
-  CHECK(stream_buf_ab_.IsEmpty());
   AllocatedBuffer buf(env(), buf_);
 
   // Only pass data on if nread > 0
@@ -1839,24 +1879,31 @@ void Http2Session::OnStreamRead(ssize_t nread, const uv_buf_t& buf_) {
     return;
   }
 
-  // Shrink to the actual amount of used data.
-  buf.Resize(nread);
+  statistics_.data_received += nread;
 
-  IncrementCurrentSessionMemory(nread);
-  OnScopeLeave on_scope_leave([&]() {
-    // Once finished handling this write, reset the stream buffer.
-    // The memory has either been free()d or was handed over to V8.
-    // We use `nread` instead of `buf.size()` here, because the buffer is
-    // cleared as part of the `.ToArrayBuffer()` call below.
-    DecrementCurrentSessionMemory(nread);
+  if (UNLIKELY(stream_buf_offset_ > 0)) {
+    // This is a very unlikely case, and should only happen if the ReadStart()
+    // call in OnStreamAfterWrite() immediately provides data. If that does
+    // happen, we concatenate the data we received with the already-stored
+    // pending input data, slicing off the already processed part.
+    AllocatedBuffer new_buf = env()->AllocateManaged(
+        stream_buf_.len - stream_buf_offset_ + nread);
+    memcpy(new_buf.data(),
+           stream_buf_.base + stream_buf_offset_,
+           stream_buf_.len - stream_buf_offset_);
+    memcpy(new_buf.data() + stream_buf_.len - stream_buf_offset_,
+           buf.data(),
+           nread);
+    buf = std::move(new_buf);
+    nread = buf.size();
+    stream_buf_offset_ = 0;
     stream_buf_ab_.Reset();
-    stream_buf_allocation_.clear();
-    stream_buf_ = uv_buf_init(nullptr, 0);
-  });
+    DecrementCurrentSessionMemory(stream_buf_offset_);
+  }
 
-  // Make sure that there was no read previously active.
-  CHECK_NULL(stream_buf_.base);
-  CHECK_EQ(stream_buf_.len, 0);
+  // Shrink to the actual amount of used data.
+  buf.Resize(nread);
+  IncrementCurrentSessionMemory(nread);
 
   // Remember the current buffer, so that OnDataChunkReceived knows the
   // offset of a DATA frame's data into the socket read buffer.
@@ -1869,8 +1916,7 @@ void Http2Session::OnStreamRead(ssize_t nread, const uv_buf_t& buf_) {
   // to copy memory.
   stream_buf_allocation_ = std::move(buf);
 
-  statistics_.data_received += nread;
-  ssize_t ret = Write(&stream_buf_, 1);
+  ssize_t ret = ConsumeHTTP2Data();
 
   if (UNLIKELY(ret < 0)) {
     Debug(this, "fatal error receiving data: %d", ret);