Cast: Refactor RTCP handling

media/cast/net/cast_transport_sender_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// This class maintains a send transport for audio and video in a Cast
+// Streaming session.
+// Audio, video frames and RTCP messages are submitted to this object
+// and then packetized and paced to the underlying UDP socket.
+//
+// The hierarchy of send transport in a Cast Streaming session:
+//
+// CastTransportSender              RTP                      RTCP
+// ------------------------------------------------------------------
+//                      TransportEncryptionHandler (A/V)
+//                      RtpSender (A/V)                   Rtcp (A/V)
+//                                      PacedSender (Shared)
+//                                      UdpTransport (Shared)
+//
+// There are objects of TransportEncryptionHandler, RtpSender and Rtcp
+// for each audio and video stream.
+// PacedSender and UdpTransport are shared between all RTP and RTCP
+// streams.
+
 #ifndef MEDIA_CAST_NET_CAST_TRANSPORT_IMPL_H_
 #define MEDIA_CAST_NET_CAST_TRANSPORT_IMPL_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "media/cast/common/transport_encryption_handler.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/logging/simple_event_subscriber.h"
 #include "media/cast/net/cast_transport_config.h"
 #include "media/cast/net/cast_transport_sender.h"
 #include "media/cast/net/pacing/paced_sender.h"
-#include "media/cast/net/rtcp/rtcp_builder.h"
+#include "media/cast/net/rtcp/rtcp.h"
 #include "media/cast/net/rtp/rtp_sender.h"
 
 namespace media {
 namespace cast {
 
 class UdpTransport;
 
 class CastTransportSenderImpl : public CastTransportSender {
  public:
-  // external_transport is only used for testing.
-  // Note that SetPacketReceiver does not work if an external
-  // transport is provided.
+  // |external_transport| is only used for testing.
   // |raw_events_callback|: Raw events will be returned on this callback
   // which will be invoked every |raw_events_callback_interval|.
   // This can be a null callback, i.e. if user is not interested in raw events.
   // |raw_events_callback_interval|: This can be |base::TimeDelta()| if
   // |raw_events_callback| is a null callback.
   CastTransportSenderImpl(
       net::NetLog* net_log,
       base::TickClock* clock,
       const net::IPEndPoint& remote_end_point,
       const CastTransportStatusCallback& status_callback,
       const BulkRawEventsCallback& raw_events_callback,
       base::TimeDelta raw_events_callback_interval,
       const scoped_refptr<base::SingleThreadTaskRunner>& transport_task_runner,
       PacketSender* external_transport);
 
   virtual ~CastTransportSenderImpl();
 
-  virtual void InitializeAudio(const CastTransportRtpConfig& config) OVERRIDE;
-  virtual void InitializeVideo(const CastTransportRtpConfig& config) OVERRIDE;
-
-  // CastTransportSender implementation.
-  virtual void SetPacketReceiver(const PacketReceiverCallback& packet_receiver)
-      OVERRIDE;
-
+  virtual void InitializeAudio(const CastTransportRtpConfig& config,
+                               const RtcpCastMessageCallback& cast_message_cb,
+                               const RtcpRttCallback& rtt_cb) OVERRIDE;
+  virtual void InitializeVideo(const CastTransportRtpConfig& config,
+                               const RtcpCastMessageCallback& cast_message_cb,
+                               const RtcpRttCallback& rtt_cb) OVERRIDE;
   virtual void InsertCodedAudioFrame(const EncodedFrame& audio_frame) OVERRIDE;
   virtual void InsertCodedVideoFrame(const EncodedFrame& video_frame) OVERRIDE;
 
-  virtual void SendRtcpFromRtpSender(uint32 packet_type_flags,
-                                     uint32 ntp_seconds,
-                                     uint32 ntp_fraction,
-                                     uint32 rtp_timestamp,
-                                     const RtcpDlrrReportBlock& dlrr,
-                                     uint32 sending_ssrc,
-                                     const std::string& c_name) OVERRIDE;
+  virtual void SendRtcpFromRtpSender(
+      bool audio,
+      base::TimeTicks current_time,
+      uint32 current_time_as_rtp_timestamp) OVERRIDE;
 
   virtual void ResendPackets(bool is_audio,
                              const MissingFramesAndPacketsMap& missing_packets,
                              bool cancel_rtx_if_not_in_list,
                              base::TimeDelta dedupe_window)
       OVERRIDE;
 
+  virtual PacketReceiverCallback PacketReceiverForTesting() OVERRIDE;
+
  private:
   // If |raw_events_callback_| is non-null, calls it with events collected
   // by |event_subscriber_| since last call.
   void SendRawEvents();
 
+  // Start receiving packets.
+  void StartReceiving();
+
+  // Called when a packet is received.
+  void OnReceivedPacket(scoped_ptr<Packet> packet);
+
+  // Called when a log message is received.
+  void OnReceivedLogMessage(EventMediaType media_type,
+                            const RtcpReceiverLogMessage& log);
+
   base::TickClock* clock_;  // Not owned by this class.
   CastTransportStatusCallback status_callback_;
   scoped_refptr<base::SingleThreadTaskRunner> transport_task_runner_;
 
+  LoggingImpl logging_;
+
+  // Interface to a UDP socket.
   scoped_ptr<UdpTransport> transport_;
-  LoggingImpl logging_;
+
+  // Packet sender that performs pacing.
   PacedSender pacer_;
-  RtcpBuilder rtcp_builder_;
+
+  // Packetizer for audio and video frames.
   scoped_ptr<RtpSender> audio_sender_;
   scoped_ptr<RtpSender> video_sender_;
 
+  // Maintains RTCP session for audio and video.
+  scoped_ptr<Rtcp> audio_rtcp_session_;
+  scoped_ptr<Rtcp> video_rtcp_session_;
+
   // Encrypts data in EncodedFrames before they are sent.  Note that it's
   // important for the encryption to happen here, in code that would execute in
   // the main browser process, for security reasons.  This helps to mitigate
   // the damage that could be caused by a compromised renderer process.
   TransportEncryptionHandler audio_encryptor_;
   TransportEncryptionHandler video_encryptor_;
 
   // This is non-null iff |raw_events_callback_| is non-null.
   scoped_ptr<SimpleEventSubscriber> event_subscriber_;
   base::RepeatingTimer<CastTransportSenderImpl> raw_events_timer_;
 
   BulkRawEventsCallback raw_events_callback_;
 
+  base::WeakPtrFactory<CastTransportSenderImpl> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(CastTransportSenderImpl);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_NET_CAST_TRANSPORT_IMPL_H_