Add FlexfecReceiveStream.

webrtc/call/flexfec_receive_stream.cc

+/*
+ *  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.
+ */
+
+#include "webrtc/call/flexfec_receive_stream.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+
+namespace webrtc {
+
+std::string FlexfecReceiveStream::Stats::ToString(int64_t time_ms) const {
+  std::stringstream ss;
+  ss << "FlexfecReceiveStream stats: " << time_ms
+     << ", {flexfec_bitrate_bps: " << flexfec_bitrate_bps << "}";
+  return ss.str();
+}
+
+namespace internal {
+
+FlexfecReceiveStream::FlexfecReceiveStream(
+    Config configuration,
+    RecoveredPacketReceiver* recovered_packet_callback)
+    : config_(configuration),
+      recovered_packet_callback_(recovered_packet_callback) {
+  if (config_.protected_media_ssrcs.empty()) {

[stefan-webrtc, 2016/10/18 18:22:24]

Break this out to a helper function so you can do:
receiver_(MaybeCreateReceiver(config_))

That way you can keep receiver_ as a const.

[brandtr, 2016/10/19 08:37:23]

Good idea! Done.

+    LOG(LS_ERROR) << "No protected media SSRC supplied. "
+                  << "This FlexfecReceiveStream will therefore be useless.";
+    receiver_ = nullptr;
+  } else {
+    // TODO(brandtr): Remove when we support multistream protection.
+    if (config_.protected_media_ssrcs.size() > 1) {
+      LOG(LS_WARNING)
+          << "The supplied FlexfecConfig contained multiple protected "
+             "media streams, but our implementation currently only "
+             "supports protecting a single media stream. This "
+             "FlexfecReceiveStream will therefore only accept media "
+             "packets from the first supplied media stream, with SSRC "
+          << config_.protected_media_ssrcs[0] << ".";
+      config_.protected_media_ssrcs.resize(1);
+    }
+    receiver_ = FlexfecReceiver::Create(config_.flexfec_ssrc,
+                                        config_.protected_media_ssrcs[0],
+                                        recovered_packet_callback_);
+  }
+
+  LOG(LS_INFO) << "FlexfecReceiveStream: " << config_.ToString();
+}
+
+FlexfecReceiveStream::~FlexfecReceiveStream() {
+  LOG(LS_INFO) << "~FlexfecReceiveStream: " << config_.ToString();
+  Stop();
+}
+
+bool FlexfecReceiveStream::AddAndProcessReceivedPacket(const uint8_t* packet,
+                                                       size_t packet_length) {
+  {
+    rtc::CritScope cs(&crit_);
+    if (!started_)
+      return false;
+  }
+  if (!receiver_)
+    return false;
+  return receiver_->AddAndProcessReceivedPacket(packet, packet_length);
+}
+
+void FlexfecReceiveStream::Start() {
+  rtc::CritScope cs(&crit_);
+  started_ = true;
+}
+
+void FlexfecReceiveStream::Stop() {
+  rtc::CritScope cs(&crit_);
+  started_ = false;
+}
+
+// TODO(brandtr): Implement this member function when we have designed the
+// stats for FlexFEC.
+FlexfecReceiveStream::Stats FlexfecReceiveStream::GetStats() const {
+  return webrtc::FlexfecReceiveStream::Stats();
+}
+
+}  // namespace internal
+
+}  // namespace webrtc