Modify PeerConnection for end-to-end QuicDataChannel usage

webrtc/api/quicdatachannel.h

Index: webrtc/api/quicdatachannel.h
diff --git a/webrtc/api/quicdatachannel.h b/webrtc/api/quicdatachannel.h
new file mode 100644
index 0000000000000000000000000000000000000000..b1f525c931928d9212184af8441cf7105ab46230
--- /dev/null
+++ b/webrtc/api/quicdatachannel.h
@@ -0,0 +1,160 @@
+/*
+ *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_API_QUICDATACHANNEL_H_
+#define WEBRTC_API_QUICDATACHANNEL_H_
+
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+
+#include "webrtc/api/datachannelinterface.h"
+#include "webrtc/api/proxy.h"
+#include "webrtc/base/copyonwritebuffer.h"
+#include "webrtc/base/bytebuffer.h"
+#include "webrtc/base/scoped_ref_ptr.h"

[pthatcher1, 2016/03/30 20:34:48]

If these aren't used in the .h, please move them to the .cc.

[mikescarlett, 2016/04/05 19:58:50]

Done.

+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/thread.h"
+
+namespace net {
+typedef uint32_t QuicStreamId;
+}  // namespace net
+
+namespace cricket {
+class QuicTransportChannel;
+class ReliableQuicStream;
+class TransportChannel;
+}  // namepsace cricket
+
+namespace webrtc {
+
+// QuicDataChannel is an implementation of DataChannelInterface based on the
+// QUIC protocol. It uses a QuicTransportChannel to establish encryption and
+// transfer data. Currently this class implements unordered, reliable delivery.
+//
+// Each time a message is sent:
+//
+// - The local peer uses QuicTransportChannel to create a ReliableQuicStream.
+//   The message is prepended with the data channel id and message id, then the
+//   ReliableQuicStream sends it to the remote peer with a FIN.
+//
+// - The remote peer's QuicSession creates a ReliableQuicStream to receive the
+// data. The

[pthatcher1, 2016/03/30 20:34:48]

Funny formatting here.

[mikescarlett, 2016/04/05 19:58:50]

I'll fix the formatting

+//   ReliableQuicStream is assigned to a QuicDataChannel with the same id as the
+//   local
+//   peer's data channel.
+//
+// - The remote QuicDataChannel queues data from the ReliableQuicStream until
+//   the QUIC stream receives a frame with a FIN.
+//
+// TODO(mikescarlett): Write blocked? closed? thread safety?
+// TODO(mikescarlett): Allow peers to negotiate QUIC flow control window size,
+// so that peers can set the maximum size of a message. Currently QUIC
+// defaults to 16KB per stream and session.
+// TODO(mikescarlett): Jitter buffer
+class QuicDataChannel : public rtc::RefCountedObject<DataChannelInterface>,
+                        public sigslot::has_slots<> {
+ public:
+  QuicDataChannel(cricket::QuicTransportChannel* quic_transport_channel,
+                  rtc::Thread* signaling_thread,
+                  rtc::Thread* worker_thread,
+                  const std::string& label,
+                  const DataChannelInit* config);
+  ~QuicDataChannel() override;
+
+  // DataChannelInterface overrides.
+  std::string label() const override { return label_; }
+  bool reliable() const override { return true; }
+  bool ordered() const override { return false; }
+  uint16_t maxRetransmitTime() const override { return -1; }
+  uint16_t maxRetransmits() const override { return -1; }
+  bool negotiated() const override { return false; }
+  int id() const override { return id_; }
+  DataState state() const override { return state_; }
+  uint64_t buffered_amount() const override { return buffered_amount_; }
+  std::string protocol() const override { return protocol_; }
+  void RegisterObserver(DataChannelObserver* observer) override;
+  void UnregisterObserver() override;
+  void Close() override;
+
+  bool Send(const DataBuffer& buffer) override;
+  // Registers a new QUIC stream to this data channel.
+  virtual void OnIncomingStream(cricket::ReliableQuicStream* stream,
+                                rtc::ByteBuffer* remaining_bytes);

[Taylor Brandstetter, 2016/04/01 23:23:41]

Maybe make this private and declare "friend QuicTransport" (QuicDataTransport if
it gets renamed). Also in the comment above the class, explain the interaction
between QuicDataChannel and QuicTransport/QuicDataTransport

[mikescarlett, 2016/04/05 19:58:50]

Is this to prevent the method from being exposed directly to PeerConnection?
What if I use Peter's suggestion of having QuicDataTransport create/destroy
channels, then have QuicDataTransport return channels of type
DataChannelInterface?

I also changed the method signature to not used ByteBuffer if that was a
concern.

[Taylor Brandstetter, 2016/04/05 22:31:17]

Peter's suggestion sounds good. But even then, making this method private makes
it clear that the method is an implementation detail, in case anything besides
PeerConnection tries to use it at some point.

[mikescarlett, 2016/04/13 16:53:36]

I made this method private. For testing I have a fake QuicDataTransport that
writes/reads everything as a string, so instead of making QuicDataTransport be a
friend directly, I thought there should be a QuicMEssageDispatcher base class
that handles both message encoding and decoding/dispatching, so that
QuicDataTransport and the testing class can subclass it.

+  rtc::Thread* worker_thread() const { return worker_thread_; }
+
+  bool has_incoming_quic_stream(net::QuicStreamId id) const {
+    return incoming_quic_streams_.find(id) != incoming_quic_streams_.end();
+  }

[Taylor Brandstetter, 2016/04/01 23:23:41]

What is this used for, and does it need to be public?

[mikescarlett, 2016/04/05 19:58:50]

This isn't needed. I removed it.

+
+  // Emitted when the state transitions to kClosed.
+  sigslot::signal1<QuicDataChannel*> SignalClosed;
+
+ protected:
+  virtual bool Send_w(const DataBuffer& buffer);
+  virtual bool WriteData_w(const char* data, size_t len);
+  virtual void OnMessage_s(const DataBuffer& received_data);
+  // Sends the data channel OPEN message.
+  // TODO(mikescarlett): Implement this method.
+  virtual void SendOpenMessage_w();
+  virtual void SetState(DataState state);
+
+  rtc::Thread* signaling_thread() { return signaling_thread_; }
+  rtc::Thread* worker_thread() { return worker_thread_; }
+
+ private:
+  // Callbacks for ReliableQuicStream.
+  void OnDataReceived(net::QuicStreamId stream_id,
+                      const char* data,
+                      size_t len);
+  void OnStreamClosed(net::QuicStreamId stream_id, int error);
+
+  // Callbacks for |quic_transport_channel_|.
+  // Called when the transport chennel becomes writable or unwritable.
+  void OnWritableState(cricket::TransportChannel* channel);
+  // Called when the QUIC session closes the connection due to handshake failure
+  // or explicit
+  // termination.
+  void OnConnectionClosed();
+
+  // QUIC transport channel which owns the QUIC session.
+  cricket::QuicTransportChannel* const quic_transport_channel_;
+  // Signaling thread for DataChannelInterface methods.
+  rtc::Thread* const signaling_thread_;
+  // Worker thread for sending/receiving data.
+  rtc::Thread* const worker_thread_;
+  // QUIC streams which have queued incoming data from the remote peer.
+  std::unordered_map<net::QuicStreamId, cricket::ReliableQuicStream*>
+      incoming_quic_streams_;
+  // Queued data for each incoming QUIC stream.
+  std::unordered_map<net::QuicStreamId, rtc::CopyOnWriteBuffer> queued_data_;
+  // Handles received data from the remote peer.
+  DataChannelObserver* observer_;
+  // Data channel id.
+  int id_;
+  // Connectivity state of the data channel.
+  DataState state_;
+  // Total bytes that are buffered among the QUIC streams.
+  uint64_t buffered_amount_;
+  // Counter for number of sent messages that is used for message ids.
+  uint64_t num_sent_messages_;
+
+  // Variables for application use.
+  const std::string& label_;
+  const std::string& protocol_;
+
+  // True if the data channel sends an OPEN message to the remote peer once
+  // this data channel is open.
+  bool send_open_message_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_API_QUICDATACHANNEL_H_