nodejs
diff --git a/‎src/node_http2.cc‎
Lines changed: 5 additions & 0 deletions b/‎src/node_http2.cc‎
Lines changed: 5 additions & 0 deletions
diff --git a/‎src/node_http2.h‎
Lines changed: 2 additions & 0 deletions b/‎src/node_http2.h‎
Lines changed: 2 additions & 0 deletions
diff --git a/‎src/stream_base-inl.h‎
Lines changed: 7 additions & 0 deletions b/‎src/stream_base-inl.h‎
Lines changed: 7 additions & 0 deletions
diff --git a/‎src/stream_base.h‎
Lines changed: 12 additions & 0 deletions b/‎src/stream_base.h‎
Lines changed: 12 additions & 0 deletions
@@ -2219,6 +2219,11 @@ ssize_t Http2Stream::Provider::Stream::OnRead(nghttp2_session* handle,
   if (amount == 0 && stream->IsWritable()) {
     CHECK(stream->queue_.empty());
     DEBUG_HTTP2SESSION2(session, "deferring stream %d", id);
+    stream->EmitWantsWrite(length);
+    if (stream->available_outbound_length_ > 0 || !stream->IsWritable()) {
+      // EmitWantsWrite() did something interesting synchronously, restart:
+      return OnRead(handle, id, buf, length, flags, source, user_data);
+    }
     return NGHTTP2_ERR_DEFERRED;
   }
 
 
@@ -573,6 +573,8 @@ class Http2Stream : public AsyncWrap,
   // Required for StreamBase
   int DoShutdown(ShutdownWrap* req_wrap) override;
 
+  bool HasWantsWrite() const override { return true; }
+
   // Initiate a response on this stream.
   inline int SubmitResponse(nghttp2_nv* nva,
                             size_t len,
 
@@ -136,6 +136,13 @@ inline void StreamResource::EmitAfterShutdown(ShutdownWrap* w, int status) {
   listener_->OnStreamAfterShutdown(w, status);
 }
 
+inline void StreamResource::EmitWantsWrite(size_t suggested_size) {
+#ifdef DEBUG
+  v8::SealHandleScope handle_scope(v8::Isolate::GetCurrent());
+#endif
+  listener_->OnStreamWantsWrite(suggested_size);
+}
+
 inline StreamBase::StreamBase(Environment* env) : env_(env) {
   PushStreamListener(&default_listener_);
 }
 
@@ -131,6 +131,13 @@ class StreamListener {
   // (and raises an assertion if there is none).
   virtual void OnStreamAfterShutdown(ShutdownWrap* w, int status);
 
+  // This is called by the stream if it determines that it wants more data
+  // to be written to it. Not all streams support this.
+  // This callback will not be called as long as there are active writes.
+  // It is not supported by all streams; `stream->HasWantsWrite()` returns
+  // true if it is supported by a stream.
+  virtual void OnStreamWantsWrite(size_t suggested_size) {}
+
   // This is called immediately before the stream is destroyed.
   virtual void OnStreamDestroy() {}
 
@@ -199,6 +206,9 @@ class StreamResource {
                       size_t count,
                       uv_stream_t* send_handle) = 0;
 
+  // Returns true if the stream supports the `OnStreamWantsWrite()` interface.
+  virtual bool HasWantsWrite() const { return false; }
+
   // Optionally, this may provide an error message to be used for
   // failing writes.
   virtual const char* Error() const;
@@ -222,6 +232,8 @@ class StreamResource {
   void EmitAfterWrite(WriteWrap* w, int status);
   // Call the current listener's OnStreamAfterShutdown() method.
   void EmitAfterShutdown(ShutdownWrap* w, int status);
+  // Call the current listener's OnStreamWantsWrite() method.
+  void EmitWantsWrite(size_t suggested_size);
 
   StreamListener* listener_ = nullptr;
   uint64_t bytes_read_ = 0;
Original file line number	Diff line number	Diff line change
@@ -136,6 +136,13 @@ inline void StreamResource::EmitAfterShutdown(ShutdownWrap* w, int status) {
136	136	listener_->OnStreamAfterShutdown(w, status);
137	137	}
138	138
	139	+ inline void StreamResource::EmitWantsWrite(size_t suggested_size) {
	140	+ #ifdef DEBUG
	141	+ v8::SealHandleScope handle_scope(v8::Isolate::GetCurrent());
	142	+ #endif
	143	+ listener_->OnStreamWantsWrite(suggested_size);
	144	+ }
	145	+
139	146	inline StreamBase::StreamBase(Environment* env) : env_(env) {
140	147	PushStreamListener(&default_listener_);
141	148	}