Adding support for Unified Plan offer/answer negotiation.

webrtc/pc/mediasession.h

 /*
  *  Copyright 2004 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.
  */
 
@@ skipping 84 matching lines @@
 
   RtpTransceiverDirection Reversed() const {
     return RtpTransceiverDirection(recv, send);
   }
 };
 
 RtpTransceiverDirection
 NegotiateRtpTransceiverDirection(RtpTransceiverDirection offer,
                                  RtpTransceiverDirection wants);
 
+struct SenderOptions {

[Taylor Brandstetter, 2017/08/05 00:39:08]

Let's add a comment explaining that a "SenderOptions" represents the options for
an RtpSender contained with an m= section.

[Zhi Huang, 2017/08/09 00:54:50]

Done.

+  std::string track_id;
+  std::string stream_id;
+  int num_sim_layers;
+};
+
+// Options for an individual media description/"m=" section.
+struct MediaDescriptionOptions {
+  MediaDescriptionOptions(MediaType type,
+                          const std::string& mid,
+                          RtpTransceiverDirection direction,
+                          bool stopped)
+      : type(type), mid(mid), direction(direction), stopped(stopped) {}
+
+  // TODO(deadbeef): When we don't support Plan B, there will only be one
+  // sender per media descritption and this can be simplified.

[Taylor Brandstetter, 2017/08/05 00:39:09]

nit: "descritption" has an extra 't'

[Zhi Huang, 2017/08/09 00:54:50]

Done.

+  void AddAudioSender(const std::string& track_id,
+                      const std::string& stream_id);
+  void AddVideoSender(const std::string& track_id,
+                      const std::string& stream_id,
+                      int num_sim_layers);
+
+  // Internally just uses sender_options.
+  void AddRtpDataChannel(const std::string& track_id,
+                         const std::string& stream_id);
+
+  MediaType type;
+  std::string mid;
+  RtpTransceiverDirection direction;
+  bool stopped;
+  TransportOptions transport_options;
+  // Note: There's no equivalent "RtpReceiverOptions" because only send
+  // stream information goes in the local descriptions.
+  std::vector<SenderOptions> sender_options;
+
+ private:
+  // Doesn't DCHECK on |type|.
+  void AddSenderInternal(const std::string& track_id,
+                         const std::string& stream_id,
+                         int num_sim_layers);
+};
+
+// Provides a mechanism for describing how m= sections should be generated.
+// The m= section with index X will use media_description_options[X]. There
+// must be an option for each existing section.

[Taylor Brandstetter, 2017/08/05 00:39:08]

Can you clarify this comment slightly? "There must be an option for each
existing section if creating an answer, or a subsequent offer."

[Zhi Huang, 2017/08/09 00:54:49]

Done.

 struct MediaSessionOptions {
-  MediaSessionOptions()
-      : recv_audio(true),
-        recv_video(false),
-        data_channel_type(DCT_NONE),
-        is_muc(false),
-        vad_enabled(true),  // When disabled, removes all CN codecs from SDP.
-        rtcp_mux_enabled(true),
-        bundle_enabled(false),
-        video_bandwidth(kAutoBandwidth),
-        data_bandwidth(kDataMaxBandwidth),
-        rtcp_cname(kDefaultRtcpCname) {}
+  MediaSessionOptions() {}
 
-  bool has_audio() const {
-    return recv_audio || HasSendMediaStream(MEDIA_TYPE_AUDIO);
-  }
-  bool has_video() const {
-    return recv_video || HasSendMediaStream(MEDIA_TYPE_VIDEO);
-  }
-  bool has_data() const { return data_channel_type != DCT_NONE; }
+  bool has_audio() const { return HasMediaDescription(MEDIA_TYPE_AUDIO); }
+  bool has_video() const { return HasMediaDescription(MEDIA_TYPE_VIDEO); }
+  bool has_data() const { return HasMediaDescription(MEDIA_TYPE_DATA); }
 
-  // Add a stream with MediaType type and id.
-  // All streams with the same sync_label will get the same CNAME.
-  // All ids must be unique.
-  void AddSendStream(MediaType type,
-                 const std::string& id,
-                 const std::string& sync_label);
-  void AddSendVideoStream(const std::string& id,
-                      const std::string& sync_label,
-                      int num_sim_layers);
-  void RemoveSendStream(MediaType type, const std::string& id);
+  bool HasMediaDescription(MediaType type) const;
 
-
-  // Helper function.
-  void AddSendStreamInternal(MediaType type,
-                         const std::string& id,
-                         const std::string& sync_label,
-                         int num_sim_layers);
-
-  bool HasSendMediaStream(MediaType type) const;
-
-  // TODO(deadbeef): Put all the audio/video/data-specific options into a map
-  // structure (content name -> options).
-  // MediaSessionDescriptionFactory assumes there will never be more than one
-  // audio/video/data content, but this will change with unified plan.
-  bool recv_audio;
-  bool recv_video;
-  DataChannelType data_channel_type;
-  bool is_muc;
-  bool vad_enabled;
-  bool rtcp_mux_enabled;
-  bool bundle_enabled;
-  // bps. -1 == auto.
-  int video_bandwidth;
-  int data_bandwidth;
-  bool enable_ice_renomination = false;
-  // content name ("mid") => options.
-  std::map<std::string, TransportOptions> transport_options;
-  std::string rtcp_cname;
+  DataChannelType data_channel_type = DCT_NONE;
+  bool is_muc = false;
+  bool vad_enabled = true;  // When disabled, removes all CN codecs from SDP.
+  bool rtcp_mux_enabled = true;
+  bool bundle_enabled = false;
+  std::string rtcp_cname = kDefaultRtcpCname;
   rtc::CryptoOptions crypto_options;
-
-  struct Stream {
-    Stream(MediaType type,
-           const std::string& id,
-           const std::string& sync_label,
-           int num_sim_layers)
-        : type(type), id(id), sync_label(sync_label),
-          num_sim_layers(num_sim_layers) {
-    }
-    MediaType type;
-    std::string id;
-    std::string sync_label;
-    int num_sim_layers;
-  };
-
-  typedef std::vector<Stream> Streams;
-  Streams streams;
+  // List of media description options in the same order that the media
+  // descriptions will be generated.
+  std::vector<MediaDescriptionOptions> media_description_options;
 };
 
 // "content" (as used in XEP-0166) descriptions for voice and video.
 class MediaContentDescription : public ContentDescription {
  public:
   MediaContentDescription() {}
 
   virtual MediaType type() const = 0;
   virtual bool has_codecs() const = 0;
 
@@ skipping 78 matching lines @@
   // Legacy streams have an ssrc, but nothing else.
   void AddLegacyStream(uint32_t ssrc) {
     streams_.push_back(StreamParams::CreateLegacy(ssrc));
   }
   void AddLegacyStream(uint32_t ssrc, uint32_t fid_ssrc) {
     StreamParams sp = StreamParams::CreateLegacy(ssrc);
     sp.AddFidSsrc(ssrc, fid_ssrc);
     streams_.push_back(sp);
   }
   // Sets the CNAME of all StreamParams if it have not been set.
-  // This can be used to set the CNAME of legacy streams.
   void SetCnameIfEmpty(const std::string& cname) {
     for (cricket::StreamParamsVec::iterator it = streams_.begin();
          it != streams_.end(); ++it) {
       if (it->cname.empty())
         it->cname = cname;
     }
   }
   uint32_t first_ssrc() const {
     if (streams_.empty()) {
       return 0;
@@ skipping 171 matching lines @@
   void set_video_rtp_header_extensions(const RtpHeaderExtensions& extensions) {
     video_rtp_extensions_ = extensions;
   }
   const RtpHeaderExtensions& video_rtp_header_extensions() const {
     return video_rtp_extensions_;
   }
   const DataCodecs& data_codecs() const { return data_codecs_; }
   void set_data_codecs(const DataCodecs& codecs) { data_codecs_ = codecs; }
   SecurePolicy secure() const { return secure_; }
   void set_secure(SecurePolicy s) { secure_ = s; }
-  // Decides if a StreamParams shall be added to the audio and video media
-  // content in SessionDescription when CreateOffer and CreateAnswer is called
-  // even if |options| don't include a Stream. This is needed to support legacy
-  // applications. |add_legacy_| is true per default.
-  void set_add_legacy_streams(bool add_legacy) { add_legacy_ = add_legacy; }
 
   void set_enable_encrypted_rtp_header_extensions(bool enable) {
     enable_encrypted_rtp_header_extensions_ = enable;
   }
 
   SessionDescription* CreateOffer(
       const MediaSessionOptions& options,
       const SessionDescription* current_description) const;
   SessionDescription* CreateAnswer(
       const SessionDescription* offer,
       const MediaSessionOptions& options,
       const SessionDescription* current_description) const;
 
  private:
   const AudioCodecs& GetAudioCodecsForOffer(
       const RtpTransceiverDirection& direction) const;
   const AudioCodecs& GetAudioCodecsForAnswer(
       const RtpTransceiverDirection& offer,
       const RtpTransceiverDirection& answer) const;
-  void GetCodecsToOffer(const SessionDescription* current_description,
-                        const AudioCodecs& supported_audio_codecs,
-                        const VideoCodecs& supported_video_codecs,
-                        const DataCodecs& supported_data_codecs,
-                        AudioCodecs* audio_codecs,
-                        VideoCodecs* video_codecs,
-                        DataCodecs* data_codecs) const;
+  void GetCodecsForOffer(const SessionDescription* current_description,
+                         AudioCodecs* audio_codecs,
+                         VideoCodecs* video_codecs,
+                         DataCodecs* data_codecs) const;
+  void GetCodecsForAnswer(const SessionDescription* current_description,
+                          const SessionDescription* remote_offer,
+                          AudioCodecs* audio_codecs,
+                          VideoCodecs* video_codecs,
+                          DataCodecs* data_codecs) const;
   void GetRtpHdrExtsToOffer(const SessionDescription* current_description,
                             RtpHeaderExtensions* audio_extensions,
                             RtpHeaderExtensions* video_extensions) const;
   bool AddTransportOffer(
       const std::string& content_name,
       const TransportOptions& transport_options,
       const SessionDescription* current_desc,
       SessionDescription* offer) const;
 
   TransportDescription* CreateTransportAnswer(
       const std::string& content_name,
       const SessionDescription* offer_desc,
       const TransportOptions& transport_options,
       const SessionDescription* current_desc,
       bool require_transport_attributes) const;
 
   bool AddTransportAnswer(
       const std::string& content_name,
       const TransportDescription& transport_desc,
       SessionDescription* answer_desc) const;
 
   // Helpers for adding media contents to the SessionDescription. Returns true
   // it succeeds or the media content is not needed, or false if there is any
   // error.
 
   bool AddAudioContentForOffer(
-      const MediaSessionOptions& options,
+      const MediaDescriptionOptions& media_description_options,
+      const MediaSessionOptions& session_options,
+      const ContentInfo* current_content,
       const SessionDescription* current_description,
       const RtpHeaderExtensions& audio_rtp_extensions,
       const AudioCodecs& audio_codecs,
       StreamParamsVec* current_streams,
       SessionDescription* desc) const;
 
   bool AddVideoContentForOffer(
-      const MediaSessionOptions& options,
+      const MediaDescriptionOptions& media_description_options,
+      const MediaSessionOptions& session_options,
+      const ContentInfo* current_content,
       const SessionDescription* current_description,
       const RtpHeaderExtensions& video_rtp_extensions,
       const VideoCodecs& video_codecs,
       StreamParamsVec* current_streams,
       SessionDescription* desc) const;
 
   bool AddDataContentForOffer(
-      const MediaSessionOptions& options,
+      const MediaDescriptionOptions& media_description_options,
+      const MediaSessionOptions& session_options,
+      const ContentInfo* current_content,
       const SessionDescription* current_description,
-      DataCodecs* data_codecs,
+      const DataCodecs& data_codecs,
       StreamParamsVec* current_streams,
       SessionDescription* desc) const;
 
-  bool AddAudioContentForAnswer(const SessionDescription* offer,
-                                const MediaSessionOptions& options,
-                                const SessionDescription* current_description,
-                                const TransportInfo* bundle_transport,
-                                StreamParamsVec* current_streams,
-                                SessionDescription* answer) const;
+  bool AddAudioContentForAnswer(
+      const MediaDescriptionOptions& media_description_options,
+      const MediaSessionOptions& session_options,
+      const ContentInfo* offer_content,
+      const SessionDescription* offer_description,
+      const ContentInfo* current_content,
+      const SessionDescription* current_description,
+      const TransportInfo* bundle_transport,
+      const AudioCodecs& audio_codecs,
+      StreamParamsVec* current_streams,
+      SessionDescription* answer) const;
 
-  bool AddVideoContentForAnswer(const SessionDescription* offer,
-                                const MediaSessionOptions& options,
-                                const SessionDescription* current_description,
-                                const TransportInfo* bundle_transport,
-                                StreamParamsVec* current_streams,
-                                SessionDescription* answer) const;
+  bool AddVideoContentForAnswer(
+      const MediaDescriptionOptions& media_description_options,
+      const MediaSessionOptions& session_options,
+      const ContentInfo* offer_content,
+      const SessionDescription* offer_description,
+      const ContentInfo* current_content,
+      const SessionDescription* current_description,
+      const TransportInfo* bundle_transport,
+      const VideoCodecs& video_codecs,
+      StreamParamsVec* current_streams,
+      SessionDescription* answer) const;
 
-  bool AddDataContentForAnswer(const SessionDescription* offer,
-                               const MediaSessionOptions& options,
-                               const SessionDescription* current_description,
-                               const TransportInfo* bundle_transport,
-                               StreamParamsVec* current_streams,
-                               SessionDescription* answer) const;
+  bool AddDataContentForAnswer(
+      const MediaDescriptionOptions& media_description_options,
+      const MediaSessionOptions& session_options,
+      const ContentInfo* offer_content,
+      const SessionDescription* offer_description,
+      const ContentInfo* current_content,
+      const SessionDescription* current_description,
+      const TransportInfo* bundle_transport,
+      const DataCodecs& data_codecs,
+      StreamParamsVec* current_streams,
+      SessionDescription* answer) const;
+
+  void ComputeAudioCodecsIntersectionAndUnion();
 
   AudioCodecs audio_send_codecs_;
   AudioCodecs audio_recv_codecs_;
+  // Intersection of send and recv.
   AudioCodecs audio_sendrecv_codecs_;
+  // Union of send and recv.
+  AudioCodecs all_audio_codecs_;
   RtpHeaderExtensions audio_rtp_extensions_;
   VideoCodecs video_codecs_;
   RtpHeaderExtensions video_rtp_extensions_;
   DataCodecs data_codecs_;
-  SecurePolicy secure_;
-  bool add_legacy_;
   bool enable_encrypted_rtp_header_extensions_ = false;
+  SecurePolicy secure_ = SEC_DISABLED;

[Taylor Brandstetter, 2017/08/05 00:39:08]

Not really related to this CL, but something that's always confused me is how
"SecurePolicy" only refers to SDES, not DTLS-SRTP. Can we rename this to
"sdes_policy_" or something similar, or add a TODO to do so?

[Zhi Huang, 2017/08/09 00:54:49]

I think it also make sense to rename the getter and setter as well so I would
prefer to make a separate CL for it.

   std::string lang_;
   const TransportDescriptionFactory* transport_desc_factory_;
 };
 
 // Convenience functions.
 bool IsMediaContent(const ContentInfo* content);
 bool IsAudioContent(const ContentInfo* content);
 bool IsVideoContent(const ContentInfo* content);
 bool IsDataContent(const ContentInfo* content);
 const ContentInfo* GetFirstMediaContent(const ContentInfos& contents,
@@ skipping 39 matching lines @@
 void GetSupportedVideoSdesCryptoSuiteNames(
     const rtc::CryptoOptions& crypto_options,
     std::vector<std::string>* crypto_suite_names);
 void GetSupportedDataSdesCryptoSuiteNames(
     const rtc::CryptoOptions& crypto_options,
     std::vector<std::string>* crypto_suite_names);
 
 }  // namespace cricket
 
 #endif  // WEBRTC_PC_MEDIASESSION_H_