Create RtcpDemuxer

webrtc/call/rtp_demuxer.h

 /*
  *  Copyright (c) 2017 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_CALL_RTP_DEMUXER_H_
 #define WEBRTC_CALL_RTP_DEMUXER_H_
 
 #include <map>
 #include <set>
 #include <string>
+#include <vector>
 
 namespace webrtc {
 
+class RsidResolutionObserver;
 class RtpPacketReceived;
 class RtpPacketSinkInterface;
 
 // This class represents the RTP demuxing, for a single RTP session (i.e., one
 // ssrc space, see RFC 7656). It isn't thread aware, leaving responsibility of
 // multithreading issues to the user of this class.
 // TODO(nisse): Should be extended to also do MID-based demux and payload-type
 // demux.
 class RtpDemuxer {
  public:
   RtpDemuxer();
   ~RtpDemuxer();
 
   // Registers a sink. The same sink can be registered for multiple ssrcs, and
   // the same ssrc can have multiple sinks. Null pointer is not allowed.
   void AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink);
 
   // Registers a sink's association to an RSID. Null pointer is not allowed.
   void AddSink(const std::string& rsid, RtpPacketSinkInterface* sink);
 
   // Removes a sink. Return value reports if anything was actually removed.
   // Null pointer is not allowed.
   bool RemoveSink(const RtpPacketSinkInterface* sink);
 
-  // Returns true if at least one matching sink was found, otherwise false.
+  // Returns true if at least one matching sink was found.
   bool OnRtpPacket(const RtpPacketReceived& packet);
 
+  // Allows other objects to be notified when RSID-SSRC associations are
+  // resolved by this object.
+  void RegisterRsidResolutionObserver(RsidResolutionObserver* observer);
+
+  // Undo a previous RegisterRsidResolutionObserver().
+  void DeregisterRsidResolutionObserver(const RsidResolutionObserver* observer);
+
  private:
   // Records a sink<->SSRC association. This can happen by explicit
   // configuration by AddSink(ssrc...), or by inferred configuration from an
   // RSID-based configuration which is resolved to an SSRC upon
   // packet reception.
   void RecordSsrcToSinkAssociation(uint32_t ssrc, RtpPacketSinkInterface* sink);
 
-  // When a new packet arrives, we attempt to resolve extra associations,
-  // such as which RSIDs are associated with which SSRCs.
-  void FindSsrcAssociations(const RtpPacketReceived& packet);
+  // When a new packet arrives, we attempt to resolve extra associations.
+  void ResolveAssociations(const RtpPacketReceived& packet);
+
+  // Find the associations of RSID to SSRCs.
+  void ResolveRsidToSsrcAssociations(const RtpPacketReceived& packet);
+
+  // Notify observers of the resolution of an RSID to an SSRC.
+  void NotifyObserversOfRsidResolution(const std::string& rsid, uint32_t ssrc);
 
   // This records the association SSRCs to sinks. Other associations, such
   // as by RSID, also end up here once the RSID, etc., is resolved to an SSRC.
   std::multimap<uint32_t, RtpPacketSinkInterface*> sinks_;
 
   // A sink may be associated with an RSID - RTP Stream ID. This tag has a
   // one-to-one association with an SSRC, but that SSRC is not yet known.
   // When it becomes known, the association of the sink to the RSID is deleted
   // from this container, and moved into |sinks_|.
   std::multimap<std::string, RtpPacketSinkInterface*> rsid_sinks_;
 
   // Iterating over |rsid_sinks_| for each incoming and performing multiple
   // string comparisons is of non-trivial cost. To avoid this cost, we only
   // check RSIDs for the first packet on each incoming SSRC stream.
   // (If RSID associations are added later, we check again.)
   std::set<uint32_t> processed_ssrcs_;
 
   // Avoid an attack that would create excessive logging.
   bool logged_max_processed_ssrcs_exceeded_ = false;
+
+  // Observers which will be notified when an RSID association to an SSRC is
+  // resolved by this object.
+  std::vector<RsidResolutionObserver*> rsid_resolution_observers_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_CALL_RTP_DEMUXER_H_