RTCStatsCollector: Utilize network thread to minimize thread hops.

webrtc/api/rtcstatscollector.h

 /*
  *  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.
  */
 
@@ skipping 23 matching lines @@
 }  // namespace cricket
 
 namespace rtc {
 class SSLCertificate;
 }  // namespace rtc
 
 namespace webrtc {
 
 class PeerConnection;
 struct SessionStats;
+struct ChannelNamePairs;
 
 class RTCStatsCollectorCallback : public virtual rtc::RefCountInterface {
  public:
   virtual ~RTCStatsCollectorCallback() {}
 
   virtual void OnStatsDelivered(
       const rtc::scoped_refptr<const RTCStatsReport>& report) = 0;
 };
 
 // All public methods of the collector are to be called on the signaling thread.
@@ skipping 36 matching lines @@
   };
   struct MediaInfo {
     rtc::Optional<cricket::VoiceMediaInfo> voice;
     rtc::Optional<cricket::VideoMediaInfo> video;
   };
 
   void AddPartialResults_s(rtc::scoped_refptr<RTCStatsReport> partial_report);
   void DeliverCachedReport();
 
   // Produces |RTCCertificateStats|.
-  void ProduceCertificateStats_s(
+  void ProduceCertificateStats_n(
       int64_t timestamp_us,
       const std::map<std::string, CertificateStatsPair>& transport_cert_stats,
       RTCStatsReport* report) const;
   // Produces |RTCCodecStats|.
-  void ProduceCodecStats_s(
+  void ProduceCodecStats_n(
       int64_t timestamp_us, const MediaInfo& media_info,
       RTCStatsReport* report) const;
   // Produces |RTCDataChannelStats|.
   void ProduceDataChannelStats_s(
       int64_t timestamp_us, RTCStatsReport* report) const;
   // Produces |RTCIceCandidatePairStats| and |RTCIceCandidateStats|.
-  void ProduceIceCandidateAndPairStats_s(
+  void ProduceIceCandidateAndPairStats_n(
       int64_t timestamp_us, const SessionStats& session_stats,
       RTCStatsReport* report) const;
   // Produces |RTCMediaStreamStats| and |RTCMediaStreamTrackStats|.
   void ProduceMediaStreamAndTrackStats_s(
       int64_t timestamp_us, RTCStatsReport* report) const;
   // Produces |RTCPeerConnectionStats|.
   void ProducePeerConnectionStats_s(
       int64_t timestamp_us, RTCStatsReport* report) const;
   // Produces |RTCInboundRTPStreamStats| and |RTCOutboundRTPStreamStats|.
-  void ProduceRTPStreamStats_s(
+  void ProduceRTPStreamStats_n(
       int64_t timestamp_us, const SessionStats& session_stats,
       const MediaInfo& media_info, RTCStatsReport* report) const;
   // Produces |RTCTransportStats|.
-  void ProduceTransportStats_s(
+  void ProduceTransportStats_n(
       int64_t timestamp_us, const SessionStats& session_stats,
       const std::map<std::string, CertificateStatsPair>& transport_cert_stats,
       RTCStatsReport* report) const;
 
   // Helper function to stats-producing functions.
   std::map<std::string, CertificateStatsPair>
-  PrepareTransportCertificateStats(const SessionStats& session_stats) const;
-  MediaInfo PrepareMediaInfo(const SessionStats& session_stats) const;
+  PrepareTransportCertificateStats_n(const SessionStats& session_stats) const;
+  std::unique_ptr<MediaInfo> PrepareMediaInfo_s() const;
 
   // Slots for signals (sigslot) that are wired up to |pc_|.
   void OnDataChannelCreated(DataChannel* channel);
   // Slots for signals (sigslot) that are wired up to |channel|.
   void OnDataChannelOpened(DataChannel* channel);
   void OnDataChannelClosed(DataChannel* channel);
 
   PeerConnection* const pc_;
   rtc::Thread* const signaling_thread_;
   rtc::Thread* const worker_thread_;
   rtc::Thread* const network_thread_;
   rtc::AsyncInvoker invoker_;
 
   int num_pending_partial_reports_;
   int64_t partial_report_timestamp_us_;
   rtc::scoped_refptr<RTCStatsReport> partial_report_;
   std::vector<rtc::scoped_refptr<RTCStatsCollectorCallback>> callbacks_;
 
+  // Set in |GetStatsReport|, used in |ProducePartialResultsOnNetworkThread|
+  // (not passed as arguments to avoid copies). This is thread safe - it is set
+  // at the start of |GetStatsReport| after making sure there are no pending
+  // stats requests in progress.
+  std::unique_ptr<ChannelNamePairs> channel_name_pairs_;
+  std::unique_ptr<MediaInfo> media_info_;
+
   // A timestamp, in microseconds, that is based on a timer that is
   // monotonically increasing. That is, even if the system clock is modified the
   // difference between the timer and this timestamp is how fresh the cached
   // report is.
   int64_t cache_timestamp_us_;
   int64_t cache_lifetime_us_;
   rtc::scoped_refptr<const RTCStatsReport> cached_report_;
 
   // Data recorded and maintained by the stats collector during its lifetime.
   // Some stats are produced from this record instead of other components.
@@ skipping 16 matching lines @@
 };
 
 const char* CandidateTypeToRTCIceCandidateTypeForTesting(
     const std::string& type);
 const char* DataStateToRTCDataChannelStateForTesting(
     DataChannelInterface::DataState state);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_RTCSTATSCOLLECTOR_H_