Added ClearTo(seq_num) to RtpFrameReferenceFinder.

webrtc/modules/video_coding/rtp_frame_reference_finder.h

 /*
  *  Copyright (c) 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.
  */
 
 #ifndef WEBRTC_MODULES_VIDEO_CODING_RTP_FRAME_REFERENCE_FINDER_H_
 #define WEBRTC_MODULES_VIDEO_CODING_RTP_FRAME_REFERENCE_FINDER_H_
 
 #include <array>
 #include <map>
 #include <memory>
-#include <queue>
+#include <deque>
 #include <set>
 #include <utility>
 
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/modules/video_coding/sequence_number_util.h"
 
 namespace webrtc {
 namespace video_coding {
 
 class FrameObject;
 class RtpFrameObject;
 
 // A complete frame is a frame which has received all its packets and all its
 // references are known.
 class OnCompleteFrameCallback {
  public:
   virtual ~OnCompleteFrameCallback() {}
   virtual void OnCompleteFrame(std::unique_ptr<FrameObject> frame) = 0;
 };
 
 class RtpFrameReferenceFinder {
  public:
   explicit RtpFrameReferenceFinder(OnCompleteFrameCallback* frame_callback);
+
+  // Manage this frame until:
+  //  - We have all information needed to determine its references, after
+  //    which |frame_callback_| is called with the completed frame, or
+  //  - We have too many stashed frames (determined by |kMaxStashedFrames)
+  //    so we drop this frame, or
+  //  - It gets cleared by ClearTo, which also means we drop it.
   void ManageFrame(std::unique_ptr<RtpFrameObject> frame);
+
+  // Notifies that padding has been received, which the reference finder
+  // might need to calculate the references of a frame.
   void PaddingReceived(uint16_t seq_num);
 
+  // Clear all stashed frames that include packets older than |seq_num|.
+  void ClearTo(uint16_t seq_num);
+
  private:
   static const uint16_t kPicIdLength = 1 << 7;
   static const uint8_t kMaxTemporalLayers = 5;
   static const int kMaxLayerInfo = 10;
   static const int kMaxStashedFrames = 10;
   static const int kMaxNotYetReceivedFrames = 20;
   static const int kMaxGofSaved = 15;
   static const int kMaxPaddingAge = 100;
 
 
@@ skipping 83 matching lines @@
   // of |kPicIdLength| to 16 bits.
   int last_unwrap_ GUARDED_BY(crit_);
 
   // Frames earlier than the last received frame that have not yet been
   // fully received.
   std::set<uint16_t, DescendingSeqNumComp<uint16_t, kPicIdLength>>
       not_yet_received_frames_ GUARDED_BY(crit_);
 
   // Frames that have been fully received but didn't have all the information
   // needed to determine their references.
-  std::queue<std::unique_ptr<RtpFrameObject>> stashed_frames_ GUARDED_BY(crit_);
+  std::deque<std::unique_ptr<RtpFrameObject>> stashed_frames_ GUARDED_BY(crit_);
 
   // Holds the information about the last completed frame for a given temporal
   // layer given a Tl0 picture index.
   std::map<uint8_t,
            std::array<int16_t, kMaxTemporalLayers>,
            DescendingSeqNumComp<uint8_t>>
       layer_info_ GUARDED_BY(crit_);
 
   // Where the current scalability structure is in the
   // |scalability_structures_| array.
@@ skipping 10 matching lines @@
   // Keep track of which picture id and which temporal layer that had the
   // up switch flag set.
   std::map<uint16_t, uint8_t, DescendingSeqNumComp<uint16_t, kPicIdLength>>
       up_switch_ GUARDED_BY(crit_);
 
   // For every temporal layer, keep a set of which frames that are missing.
   std::array<std::set<uint16_t, DescendingSeqNumComp<uint16_t, kPicIdLength>>,
              kMaxTemporalLayers>
       missing_frames_for_layer_ GUARDED_BY(crit_);
 
+  // How far frames have been cleared by sequence number. A frame will be
+  // cleared if it contains a packet with a sequence number older than
+  // |cleared_to_seq_num_|.
+  int cleared_to_seq_num_ GUARDED_BY(crit_);
+
   OnCompleteFrameCallback* frame_callback_;
 };
 
 }  // namespace video_coding
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_RTP_FRAME_REFERENCE_FINDER_H_