Make configuration logic harsher in 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 {
 
 // TODO(brandtr): Update this function when we support multistream protection.
-std::unique_ptr<FlexfecReceiver> MaybeUpdateConfigAndCreateFlexfecReceiver(
-    FlexfecReceiveStream::Config* config,
+std::unique_ptr<FlexfecReceiver> MaybeCreateFlexfecReceiver(
+    const FlexfecReceiveStream::Config& config,
     RecoveredPacketReceiver* recovered_packet_callback) {
-  if (config->protected_media_ssrcs.empty()) {
-    LOG(LS_ERROR) << "No protected media SSRC supplied. "
-                  << "This FlexfecReceiveStream will therefore be useless.";
+  if (config.flexfec_payload_type < 0) {
+    LOG(LS_WARNING) << "Invalid FlexFEC payload type given. "
+                    << "This FlexfecReceiveStream will therefore be useless.";
     return nullptr;
-  } else if (config->protected_media_ssrcs.size() > 1) {
+  }
+  RTC_DCHECK_GE(config.flexfec_payload_type, 0);
+  RTC_DCHECK_LE(config.flexfec_payload_type, 127);
+  if (config.flexfec_ssrc == 0) {
+    LOG(LS_WARNING) << "Invalid FlexFEC SSRC given. "
+                    << "This FlexfecReceiveStream will therefore be useless.";
+    return nullptr;
+  }
+  if (config.protected_media_ssrcs.empty()) {
+    LOG(LS_WARNING) << "No protected media SSRC supplied. "
+                    << "This FlexfecReceiveStream will therefore be useless.";
+    return nullptr;
+  }
+
+  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);
+           "supports protecting a single media stream. "
+           "To avoid confusion, disabling FlexFEC completely.";
+    return nullptr;
   }
-  return std::unique_ptr<FlexfecReceiver>(new FlexfecReceiver(
-      config->flexfec_ssrc, config->protected_media_ssrcs[0],
-      recovered_packet_callback));
+  RTC_DCHECK_EQ(1U, config.protected_media_ssrcs.size());
+  return std::unique_ptr<FlexfecReceiver>(
+      new FlexfecReceiver(config.flexfec_ssrc, config.protected_media_ssrcs[0],
+                          recovered_packet_callback));
 }
 
 }  // namespace
 
 namespace internal {
 
 FlexfecReceiveStream::FlexfecReceiveStream(
     Config configuration,
     RecoveredPacketReceiver* recovered_packet_callback)
     : started_(false),
       config_(configuration),
-      receiver_(MaybeUpdateConfigAndCreateFlexfecReceiver(
-          &config_,
-          recovered_packet_callback)) {
+      receiver_(
+          MaybeCreateFlexfecReceiver(config_, 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) {
@@ skipping 19 matching lines @@
 
 // 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