NetEq: Rectify the implementation of PacketBuffer::DiscardOldPackets

webrtc/modules/audio_coding/neteq/packet_buffer.cc

 /*
  *  Copyright (c) 2012 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 203 matching lines @@
   // Assert that the packet sanity checks in InsertPacket method works.
   RTC_DCHECK(!buffer_.front().empty());
   buffer_.pop_front();
   stats->PacketsDiscarded(1);
   return kOK;
 }
 
 void PacketBuffer::DiscardOldPackets(uint32_t timestamp_limit,
                                      uint32_t horizon_samples,
                                      StatisticsCalculator* stats) {
-  // TODO(minyue): the following implementation is wrong. It won't discard
-  // old packets if the buffer_.front() is newer than timestamp_limit -
-  // horizon_samples. https://bugs.chromium.org/p/webrtc/issues/detail?id=7937
-  while (!Empty() && timestamp_limit != buffer_.front().timestamp &&
-         IsObsoleteTimestamp(buffer_.front().timestamp, timestamp_limit,
-                             horizon_samples)) {
-    if (DiscardNextPacket(stats) != kOK) {
-      assert(false);  // Must be ok by design.
-    }
+  const size_t old_size = buffer_.size();
+  buffer_.remove_if([timestamp_limit, horizon_samples](const Packet& p) {
+    return timestamp_limit != p.timestamp &&
+           IsObsoleteTimestamp(p.timestamp, timestamp_limit, horizon_samples);
+  });
+  if (old_size > buffer_.size()) {
+    stats->PacketsDiscarded(old_size - buffer_.size());
   }
 }
 
 void PacketBuffer::DiscardAllOldPackets(uint32_t timestamp_limit,
                                         StatisticsCalculator* stats) {
   DiscardOldPackets(timestamp_limit, 0, stats);
 }
 
 void PacketBuffer::DiscardPacketsWithPayloadType(uint8_t payload_type,
                                                  StatisticsCalculator* stats) {
@@ skipping 34 matching lines @@
   }
   return num_samples;
 }
 
 void PacketBuffer::BufferStat(int* num_packets, int* max_num_packets) const {
   *num_packets = static_cast<int>(buffer_.size());
   *max_num_packets = static_cast<int>(max_number_of_packets_);
 }
 
 }  // namespace webrtc