text: /*
   *  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.
   */
  
  #include "call/rtcp_demuxer.h"
  
  #include "api/rtp_headers.h"
  #include "call/rtcp_packet_sink_interface.h"
  #include "call/rtp_rtcp_demuxer_helper.h"
  #include "common_types.h"  // NOLINT(build/include)
  #include "rtc_base/checks.h"
  
  namespace webrtc {
  
  RtcpDemuxer::RtcpDemuxer() = default;
  
  RtcpDemuxer::~RtcpDemuxer() {
    RTC_DCHECK(ssrc_sinks_.empty());
    RTC_DCHECK(rsid_sinks_.empty());
    RTC_DCHECK(broadcast_sinks_.empty());
  }
  
  void RtcpDemuxer::AddSink(uint32_t sender_ssrc, RtcpPacketSinkInterface* sink) {
    RTC_DCHECK(sink);
    RTC_DCHECK(!ContainerHasKey(broadcast_sinks_, sink));
    RTC_DCHECK(!MultimapAssociationExists(ssrc_sinks_, sender_ssrc, sink));
    ssrc_sinks_.emplace(sender_ssrc, sink);
  }
  
  void RtcpDemuxer::AddSink(const std::string& rsid,
                            RtcpPacketSinkInterface* sink) {
    RTC_DCHECK(StreamId::IsLegalRsidName(rsid));
    RTC_DCHECK(sink);
    RTC_DCHECK(!ContainerHasKey(broadcast_sinks_, sink));
    RTC_DCHECK(!MultimapAssociationExists(rsid_sinks_, rsid, sink));
    rsid_sinks_.emplace(rsid, sink);
  }
  
  void RtcpDemuxer::AddBroadcastSink(RtcpPacketSinkInterface* sink) {
    RTC_DCHECK(sink);
    RTC_DCHECK(!MultimapHasValue(ssrc_sinks_, sink));
    RTC_DCHECK(!MultimapHasValue(rsid_sinks_, sink));
    RTC_DCHECK(!ContainerHasKey(broadcast_sinks_, sink));
    broadcast_sinks_.push_back(sink);
  }
  
  void RtcpDemuxer::RemoveSink(const RtcpPacketSinkInterface* sink) {
    RTC_DCHECK(sink);
    size_t removal_count = RemoveFromMultimapByValue(&ssrc_sinks_, sink) +
                           RemoveFromMultimapByValue(&rsid_sinks_, sink);
    RTC_DCHECK_GT(removal_count, 0);
  }
  
  void RtcpDemuxer::RemoveBroadcastSink(const RtcpPacketSinkInterface* sink) {
    RTC_DCHECK(sink);
    auto it = std::find(broadcast_sinks_.begin(), broadcast_sinks_.end(), sink);
    RTC_DCHECK(it != broadcast_sinks_.end());
    broadcast_sinks_.erase(it);
  }
  
  void RtcpDemuxer::OnRtcpPacket(rtc::ArrayView<const uint8_t> packet) {
    // Perform sender-SSRC-based demuxing for packets with a sender-SSRC.
    absl::optional<uint32_t> sender_ssrc = ParseRtcpPacketSenderSsrc(packet);
    if (sender_ssrc) {
      auto it_range = ssrc_sinks_.equal_range(*sender_ssrc);
      for (auto it = it_range.first; it != it_range.second; ++it) {
        it->second->OnRtcpPacket(packet);
      }
    }
  
    // All packets, even those without a sender-SSRC, are broadcast to sinks
    // which listen to broadcasts.
    for (RtcpPacketSinkInterface* sink : broadcast_sinks_) {
      sink->OnRtcpPacket(packet);
    }
  }
  
  void RtcpDemuxer::OnSsrcBoundToRsid(const std::string& rsid, uint32_t ssrc) {
    // Record the new SSRC association for all of the sinks that were associated
    // with the RSID.
    auto it_range = rsid_sinks_.equal_range(rsid);
    for (auto it = it_range.first; it != it_range.second; ++it) {
      RtcpPacketSinkInterface* sink = it->second;
      // Watch out for pre-existing SSRC-based associations.
      if (!MultimapAssociationExists(ssrc_sinks_, ssrc, sink)) {
        AddSink(ssrc, sink);
      }
    }
  
    // RSIDs are uniquely associated with SSRCs; no need to keep in memory
    // the RSID-to-sink association of resolved RSIDs.
    rsid_sinks_.erase(it_range.first, it_range.second);
  }
  
  }  // namespace webrtc
  