Reland of Split iOS sdk in to separate targets

webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnection.mm

+/*
+ *  Copyright 2015 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.
+ */
+
+#import "RTCPeerConnection+Private.h"
+
+#import "NSString+StdString.h"
+#import "RTCConfiguration+Private.h"
+#import "RTCDataChannel+Private.h"
+#import "RTCIceCandidate+Private.h"
+#import "RTCLegacyStatsReport+Private.h"
+#import "RTCMediaConstraints+Private.h"
+#import "RTCMediaStream+Private.h"
+#import "RTCPeerConnectionFactory+Private.h"
+#import "RTCRtpReceiver+Private.h"
+#import "RTCRtpSender+Private.h"
+#import "RTCSessionDescription+Private.h"
+#import "WebRTC/RTCLogging.h"
+
+#include <memory>
+
+#include "webrtc/api/jsepicecandidate.h"
+#include "webrtc/base/checks.h"
+
+NSString * const kRTCPeerConnectionErrorDomain =
+    @"org.webrtc.RTCPeerConnection";
+int const kRTCPeerConnnectionSessionDescriptionError = -1;
+
+namespace webrtc {
+
+class CreateSessionDescriptionObserverAdapter
+    : public CreateSessionDescriptionObserver {
+ public:
+  CreateSessionDescriptionObserverAdapter(
+      void (^completionHandler)(RTCSessionDescription *sessionDescription,
+                                NSError *error)) {
+    completion_handler_ = completionHandler;
+  }
+
+  ~CreateSessionDescriptionObserverAdapter() {
+    completion_handler_ = nil;
+  }
+
+  void OnSuccess(SessionDescriptionInterface *desc) override {
+    RTC_DCHECK(completion_handler_);
+    std::unique_ptr<webrtc::SessionDescriptionInterface> description =
+        std::unique_ptr<webrtc::SessionDescriptionInterface>(desc);
+    RTCSessionDescription* session =
+        [[RTCSessionDescription alloc] initWithNativeDescription:
+            description.get()];
+    completion_handler_(session, nil);
+    completion_handler_ = nil;
+  }
+
+  void OnFailure(const std::string& error) override {
+    RTC_DCHECK(completion_handler_);
+    NSString* str = [NSString stringForStdString:error];
+    NSError* err =
+        [NSError errorWithDomain:kRTCPeerConnectionErrorDomain
+                            code:kRTCPeerConnnectionSessionDescriptionError
+                        userInfo:@{ NSLocalizedDescriptionKey : str }];
+    completion_handler_(nil, err);
+    completion_handler_ = nil;
+  }
+
+ private:
+  void (^completion_handler_)
+      (RTCSessionDescription *sessionDescription, NSError *error);
+};
+
+class SetSessionDescriptionObserverAdapter :
+    public SetSessionDescriptionObserver {
+ public:
+  SetSessionDescriptionObserverAdapter(void (^completionHandler)
+      (NSError *error)) {
+    completion_handler_ = completionHandler;
+  }
+
+  ~SetSessionDescriptionObserverAdapter() {
+    completion_handler_ = nil;
+  }
+
+  void OnSuccess() override {
+    RTC_DCHECK(completion_handler_);
+    completion_handler_(nil);
+    completion_handler_ = nil;
+  }
+
+  void OnFailure(const std::string& error) override {
+    RTC_DCHECK(completion_handler_);
+    NSString* str = [NSString stringForStdString:error];
+    NSError* err =
+        [NSError errorWithDomain:kRTCPeerConnectionErrorDomain
+                            code:kRTCPeerConnnectionSessionDescriptionError
+                        userInfo:@{ NSLocalizedDescriptionKey : str }];
+    completion_handler_(err);
+    completion_handler_ = nil;
+  }
+
+ private:
+  void (^completion_handler_)(NSError *error);
+};
+
+PeerConnectionDelegateAdapter::PeerConnectionDelegateAdapter(
+    RTCPeerConnection *peerConnection) {
+  peer_connection_ = peerConnection;
+}
+
+PeerConnectionDelegateAdapter::~PeerConnectionDelegateAdapter() {
+  peer_connection_ = nil;
+}
+
+void PeerConnectionDelegateAdapter::OnSignalingChange(
+    PeerConnectionInterface::SignalingState new_state) {
+  RTCSignalingState state =
+      [[RTCPeerConnection class] signalingStateForNativeState:new_state];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                   didChangeSignalingState:state];
+}
+
+void PeerConnectionDelegateAdapter::OnAddStream(
+    rtc::scoped_refptr<MediaStreamInterface> stream) {
+  RTCMediaStream *mediaStream =
+      [[RTCMediaStream alloc] initWithNativeMediaStream:stream];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                              didAddStream:mediaStream];
+}
+
+void PeerConnectionDelegateAdapter::OnRemoveStream(
+    rtc::scoped_refptr<MediaStreamInterface> stream) {
+  RTCMediaStream *mediaStream =
+      [[RTCMediaStream alloc] initWithNativeMediaStream:stream];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                           didRemoveStream:mediaStream];
+}
+
+void PeerConnectionDelegateAdapter::OnDataChannel(
+    rtc::scoped_refptr<DataChannelInterface> data_channel) {
+  RTCDataChannel *dataChannel =
+      [[RTCDataChannel alloc] initWithNativeDataChannel:data_channel];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                        didOpenDataChannel:dataChannel];
+}
+
+void PeerConnectionDelegateAdapter::OnRenegotiationNeeded() {
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnectionShouldNegotiate:peer_connection];
+}
+
+void PeerConnectionDelegateAdapter::OnIceConnectionChange(
+    PeerConnectionInterface::IceConnectionState new_state) {
+  RTCIceConnectionState state =
+      [[RTCPeerConnection class] iceConnectionStateForNativeState:new_state];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+               didChangeIceConnectionState:state];
+}
+
+void PeerConnectionDelegateAdapter::OnIceGatheringChange(
+    PeerConnectionInterface::IceGatheringState new_state) {
+  RTCIceGatheringState state =
+      [[RTCPeerConnection class] iceGatheringStateForNativeState:new_state];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                didChangeIceGatheringState:state];
+}
+
+void PeerConnectionDelegateAdapter::OnIceCandidate(
+    const IceCandidateInterface *candidate) {
+  RTCIceCandidate *iceCandidate =
+      [[RTCIceCandidate alloc] initWithNativeCandidate:candidate];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                   didGenerateIceCandidate:iceCandidate];
+}
+
+void PeerConnectionDelegateAdapter::OnIceCandidatesRemoved(
+    const std::vector<cricket::Candidate>& candidates) {
+  NSMutableArray* ice_candidates =
+      [NSMutableArray arrayWithCapacity:candidates.size()];
+  for (const auto& candidate : candidates) {
+    std::unique_ptr<JsepIceCandidate> candidate_wrapper(
+        new JsepIceCandidate(candidate.transport_name(), -1, candidate));
+    RTCIceCandidate* ice_candidate = [[RTCIceCandidate alloc]
+        initWithNativeCandidate:candidate_wrapper.get()];
+    [ice_candidates addObject:ice_candidate];
+  }
+  RTCPeerConnection* peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+                    didRemoveIceCandidates:ice_candidates];
+}
+
+}  // namespace webrtc
+
+
+@implementation RTCPeerConnection {
+  NSMutableArray<RTCMediaStream *> *_localStreams;
+  std::unique_ptr<webrtc::PeerConnectionDelegateAdapter> _observer;
+  rtc::scoped_refptr<webrtc::PeerConnectionInterface> _peerConnection;
+  std::unique_ptr<webrtc::MediaConstraints> _nativeConstraints;
+  BOOL _hasStartedRtcEventLog;
+}
+
+@synthesize delegate = _delegate;
+
+- (instancetype)initWithFactory:(RTCPeerConnectionFactory *)factory
+                  configuration:(RTCConfiguration *)configuration
+                    constraints:(RTCMediaConstraints *)constraints
+                       delegate:(id<RTCPeerConnectionDelegate>)delegate {
+  NSParameterAssert(factory);
+  std::unique_ptr<webrtc::PeerConnectionInterface::RTCConfiguration> config(
+      [configuration createNativeConfiguration]);
+  if (!config) {
+    return nil;
+  }
+  if (self = [super init]) {
+    _observer.reset(new webrtc::PeerConnectionDelegateAdapter(self));
+    _nativeConstraints = constraints.nativeConstraints;
+    CopyConstraintsIntoRtcConfiguration(_nativeConstraints.get(),
+                                        config.get());
+    _peerConnection =
+        factory.nativeFactory->CreatePeerConnection(*config,
+                                                    nullptr,
+                                                    nullptr,
+                                                    _observer.get());
+    if (!_peerConnection) {
+      return nil;
+    }
+    _localStreams = [[NSMutableArray alloc] init];
+    _delegate = delegate;
+  }
+  return self;
+}
+
+- (NSArray<RTCMediaStream *> *)localStreams {
+  return [_localStreams copy];
+}
+
+- (RTCSessionDescription *)localDescription {
+  const webrtc::SessionDescriptionInterface *description =
+      _peerConnection->local_description();
+  return description ?
+      [[RTCSessionDescription alloc] initWithNativeDescription:description]
+          : nil;
+}
+
+- (RTCSessionDescription *)remoteDescription {
+  const webrtc::SessionDescriptionInterface *description =
+      _peerConnection->remote_description();
+  return description ?
+      [[RTCSessionDescription alloc] initWithNativeDescription:description]
+          : nil;
+}
+
+- (RTCSignalingState)signalingState {
+  return [[self class]
+      signalingStateForNativeState:_peerConnection->signaling_state()];
+}
+
+- (RTCIceConnectionState)iceConnectionState {
+  return [[self class] iceConnectionStateForNativeState:
+      _peerConnection->ice_connection_state()];
+}
+
+- (RTCIceGatheringState)iceGatheringState {
+  return [[self class] iceGatheringStateForNativeState:
+      _peerConnection->ice_gathering_state()];
+}
+
+- (BOOL)setConfiguration:(RTCConfiguration *)configuration {
+  std::unique_ptr<webrtc::PeerConnectionInterface::RTCConfiguration> config(
+      [configuration createNativeConfiguration]);
+  if (!config) {
+    return NO;
+  }
+  CopyConstraintsIntoRtcConfiguration(_nativeConstraints.get(),
+                                      config.get());
+  return _peerConnection->SetConfiguration(*config);
+}
+
+- (RTCConfiguration *)configuration {
+  webrtc::PeerConnectionInterface::RTCConfiguration config =
+    _peerConnection->GetConfiguration();
+  return [[RTCConfiguration alloc] initWithNativeConfiguration:config];
+}
+
+- (void)close {
+  _peerConnection->Close();
+}
+
+- (void)addIceCandidate:(RTCIceCandidate *)candidate {
+  std::unique_ptr<const webrtc::IceCandidateInterface> iceCandidate(
+      candidate.nativeCandidate);
+  _peerConnection->AddIceCandidate(iceCandidate.get());
+}
+
+- (void)removeIceCandidates:(NSArray<RTCIceCandidate *> *)iceCandidates {
+  std::vector<cricket::Candidate> candidates;
+  for (RTCIceCandidate *iceCandidate in iceCandidates) {
+    std::unique_ptr<const webrtc::IceCandidateInterface> candidate(
+        iceCandidate.nativeCandidate);
+    if (candidate) {
+      candidates.push_back(candidate->candidate());
+      // Need to fill the transport name from the sdp_mid.
+      candidates.back().set_transport_name(candidate->sdp_mid());
+    }
+  }
+  if (!candidates.empty()) {
+    _peerConnection->RemoveIceCandidates(candidates);
+  }
+}
+
+- (void)addStream:(RTCMediaStream *)stream {
+  if (!_peerConnection->AddStream(stream.nativeMediaStream)) {
+    RTCLogError(@"Failed to add stream: %@", stream);
+    return;
+  }
+  [_localStreams addObject:stream];
+}
+
+- (void)removeStream:(RTCMediaStream *)stream {
+  _peerConnection->RemoveStream(stream.nativeMediaStream);
+  [_localStreams removeObject:stream];
+}
+
+- (void)offerForConstraints:(RTCMediaConstraints *)constraints
+          completionHandler:
+    (void (^)(RTCSessionDescription *sessionDescription,
+              NSError *error))completionHandler {
+  rtc::scoped_refptr<webrtc::CreateSessionDescriptionObserverAdapter>
+      observer(new rtc::RefCountedObject
+          <webrtc::CreateSessionDescriptionObserverAdapter>(completionHandler));
+  _peerConnection->CreateOffer(observer, constraints.nativeConstraints.get());
+}
+
+- (void)answerForConstraints:(RTCMediaConstraints *)constraints
+           completionHandler:
+    (void (^)(RTCSessionDescription *sessionDescription,
+              NSError *error))completionHandler {
+  rtc::scoped_refptr<webrtc::CreateSessionDescriptionObserverAdapter>
+      observer(new rtc::RefCountedObject
+          <webrtc::CreateSessionDescriptionObserverAdapter>(completionHandler));
+  _peerConnection->CreateAnswer(observer, constraints.nativeConstraints.get());
+}
+
+- (void)setLocalDescription:(RTCSessionDescription *)sdp
+          completionHandler:(void (^)(NSError *error))completionHandler {
+  rtc::scoped_refptr<webrtc::SetSessionDescriptionObserverAdapter> observer(
+      new rtc::RefCountedObject<webrtc::SetSessionDescriptionObserverAdapter>(
+          completionHandler));
+  _peerConnection->SetLocalDescription(observer, sdp.nativeDescription);
+}
+
+- (void)setRemoteDescription:(RTCSessionDescription *)sdp
+           completionHandler:(void (^)(NSError *error))completionHandler {
+  rtc::scoped_refptr<webrtc::SetSessionDescriptionObserverAdapter> observer(
+      new rtc::RefCountedObject<webrtc::SetSessionDescriptionObserverAdapter>(
+          completionHandler));
+  _peerConnection->SetRemoteDescription(observer, sdp.nativeDescription);
+}
+
+- (BOOL)startRtcEventLogWithFilePath:(NSString *)filePath
+                      maxSizeInBytes:(int64_t)maxSizeInBytes {
+  RTC_DCHECK(filePath.length);
+  RTC_DCHECK_GT(maxSizeInBytes, 0);
+  RTC_DCHECK(!_hasStartedRtcEventLog);
+  if (_hasStartedRtcEventLog) {
+    RTCLogError(@"Event logging already started.");
+    return NO;
+  }
+  int fd = open(filePath.UTF8String, O_WRONLY | O_CREAT | O_TRUNC,
+                S_IRUSR | S_IWUSR);
+  if (fd < 0) {
+    RTCLogError(@"Error opening file: %@. Error: %d", filePath, errno);
+    return NO;
+  }
+  _hasStartedRtcEventLog =
+      _peerConnection->StartRtcEventLog(fd, maxSizeInBytes);
+  return _hasStartedRtcEventLog;
+}
+
+- (void)stopRtcEventLog {
+  _peerConnection->StopRtcEventLog();
+  _hasStartedRtcEventLog = NO;
+}
+
+- (RTCRtpSender *)senderWithKind:(NSString *)kind
+                        streamId:(NSString *)streamId {
+  std::string nativeKind = [NSString stdStringForString:kind];
+  std::string nativeStreamId = [NSString stdStringForString:streamId];
+  rtc::scoped_refptr<webrtc::RtpSenderInterface> nativeSender(
+      _peerConnection->CreateSender(nativeKind, nativeStreamId));
+  return nativeSender ?
+      [[RTCRtpSender alloc] initWithNativeRtpSender:nativeSender]
+      : nil;
+}
+
+- (NSArray<RTCRtpSender *> *)senders {
+  std::vector<rtc::scoped_refptr<webrtc::RtpSenderInterface>> nativeSenders(
+      _peerConnection->GetSenders());
+  NSMutableArray *senders = [[NSMutableArray alloc] init];
+  for (const auto &nativeSender : nativeSenders) {
+    RTCRtpSender *sender =
+        [[RTCRtpSender alloc] initWithNativeRtpSender:nativeSender];
+    [senders addObject:sender];
+  }
+  return senders;
+}
+
+- (NSArray<RTCRtpReceiver *> *)receivers {
+  std::vector<rtc::scoped_refptr<webrtc::RtpReceiverInterface>> nativeReceivers(
+      _peerConnection->GetReceivers());
+  NSMutableArray *receivers = [[NSMutableArray alloc] init];
+  for (const auto &nativeReceiver : nativeReceivers) {
+    RTCRtpReceiver *receiver =
+        [[RTCRtpReceiver alloc] initWithNativeRtpReceiver:nativeReceiver];
+    [receivers addObject:receiver];
+  }
+  return receivers;
+}
+
+#pragma mark - Private
+
++ (webrtc::PeerConnectionInterface::SignalingState)nativeSignalingStateForState:
+    (RTCSignalingState)state {
+  switch (state) {
+    case RTCSignalingStateStable:
+      return webrtc::PeerConnectionInterface::kStable;
+    case RTCSignalingStateHaveLocalOffer:
+      return webrtc::PeerConnectionInterface::kHaveLocalOffer;
+    case RTCSignalingStateHaveLocalPrAnswer:
+      return webrtc::PeerConnectionInterface::kHaveLocalPrAnswer;
+    case RTCSignalingStateHaveRemoteOffer:
+      return webrtc::PeerConnectionInterface::kHaveRemoteOffer;
+    case RTCSignalingStateHaveRemotePrAnswer:
+      return webrtc::PeerConnectionInterface::kHaveRemotePrAnswer;
+    case RTCSignalingStateClosed:
+      return webrtc::PeerConnectionInterface::kClosed;
+  }
+}
+
++ (RTCSignalingState)signalingStateForNativeState:
+    (webrtc::PeerConnectionInterface::SignalingState)nativeState {
+  switch (nativeState) {
+    case webrtc::PeerConnectionInterface::kStable:
+      return RTCSignalingStateStable;
+    case webrtc::PeerConnectionInterface::kHaveLocalOffer:
+      return RTCSignalingStateHaveLocalOffer;
+    case webrtc::PeerConnectionInterface::kHaveLocalPrAnswer:
+      return RTCSignalingStateHaveLocalPrAnswer;
+    case webrtc::PeerConnectionInterface::kHaveRemoteOffer:
+      return RTCSignalingStateHaveRemoteOffer;
+    case webrtc::PeerConnectionInterface::kHaveRemotePrAnswer:
+      return RTCSignalingStateHaveRemotePrAnswer;
+    case webrtc::PeerConnectionInterface::kClosed:
+      return RTCSignalingStateClosed;
+  }
+}
+
++ (NSString *)stringForSignalingState:(RTCSignalingState)state {
+  switch (state) {
+    case RTCSignalingStateStable:
+      return @"STABLE";
+    case RTCSignalingStateHaveLocalOffer:
+      return @"HAVE_LOCAL_OFFER";
+    case RTCSignalingStateHaveLocalPrAnswer:
+      return @"HAVE_LOCAL_PRANSWER";
+    case RTCSignalingStateHaveRemoteOffer:
+      return @"HAVE_REMOTE_OFFER";
+    case RTCSignalingStateHaveRemotePrAnswer:
+      return @"HAVE_REMOTE_PRANSWER";
+    case RTCSignalingStateClosed:
+      return @"CLOSED";
+  }
+}
+
++ (webrtc::PeerConnectionInterface::IceConnectionState)
+    nativeIceConnectionStateForState:(RTCIceConnectionState)state {
+  switch (state) {
+    case RTCIceConnectionStateNew:
+      return webrtc::PeerConnectionInterface::kIceConnectionNew;
+    case RTCIceConnectionStateChecking:
+      return webrtc::PeerConnectionInterface::kIceConnectionChecking;
+    case RTCIceConnectionStateConnected:
+      return webrtc::PeerConnectionInterface::kIceConnectionConnected;
+    case RTCIceConnectionStateCompleted:
+      return webrtc::PeerConnectionInterface::kIceConnectionCompleted;
+    case RTCIceConnectionStateFailed:
+      return webrtc::PeerConnectionInterface::kIceConnectionFailed;
+    case RTCIceConnectionStateDisconnected:
+      return webrtc::PeerConnectionInterface::kIceConnectionDisconnected;
+    case RTCIceConnectionStateClosed:
+      return webrtc::PeerConnectionInterface::kIceConnectionClosed;
+    case RTCIceConnectionStateCount:
+      return webrtc::PeerConnectionInterface::kIceConnectionMax;
+  }
+}
+
++ (RTCIceConnectionState)iceConnectionStateForNativeState:
+    (webrtc::PeerConnectionInterface::IceConnectionState)nativeState {
+  switch (nativeState) {
+    case webrtc::PeerConnectionInterface::kIceConnectionNew:
+      return RTCIceConnectionStateNew;
+    case webrtc::PeerConnectionInterface::kIceConnectionChecking:
+      return RTCIceConnectionStateChecking;
+    case webrtc::PeerConnectionInterface::kIceConnectionConnected:
+      return RTCIceConnectionStateConnected;
+    case webrtc::PeerConnectionInterface::kIceConnectionCompleted:
+      return RTCIceConnectionStateCompleted;
+    case webrtc::PeerConnectionInterface::kIceConnectionFailed:
+      return RTCIceConnectionStateFailed;
+    case webrtc::PeerConnectionInterface::kIceConnectionDisconnected:
+      return RTCIceConnectionStateDisconnected;
+    case webrtc::PeerConnectionInterface::kIceConnectionClosed:
+      return RTCIceConnectionStateClosed;
+    case webrtc::PeerConnectionInterface::kIceConnectionMax:
+      return RTCIceConnectionStateCount;
+  }
+}
+
++ (NSString *)stringForIceConnectionState:(RTCIceConnectionState)state {
+  switch (state) {
+    case RTCIceConnectionStateNew:
+      return @"NEW";
+    case RTCIceConnectionStateChecking:
+      return @"CHECKING";
+    case RTCIceConnectionStateConnected:
+      return @"CONNECTED";
+    case RTCIceConnectionStateCompleted:
+      return @"COMPLETED";
+    case RTCIceConnectionStateFailed:
+      return @"FAILED";
+    case RTCIceConnectionStateDisconnected:
+      return @"DISCONNECTED";
+    case RTCIceConnectionStateClosed:
+      return @"CLOSED";
+    case RTCIceConnectionStateCount:
+      return @"COUNT";
+  }
+}
+
++ (webrtc::PeerConnectionInterface::IceGatheringState)
+    nativeIceGatheringStateForState:(RTCIceGatheringState)state {
+  switch (state) {
+    case RTCIceGatheringStateNew:
+      return webrtc::PeerConnectionInterface::kIceGatheringNew;
+    case RTCIceGatheringStateGathering:
+      return webrtc::PeerConnectionInterface::kIceGatheringGathering;
+    case RTCIceGatheringStateComplete:
+      return webrtc::PeerConnectionInterface::kIceGatheringComplete;
+  }
+}
+
++ (RTCIceGatheringState)iceGatheringStateForNativeState:
+    (webrtc::PeerConnectionInterface::IceGatheringState)nativeState {
+  switch (nativeState) {
+    case webrtc::PeerConnectionInterface::kIceGatheringNew:
+      return RTCIceGatheringStateNew;
+    case webrtc::PeerConnectionInterface::kIceGatheringGathering:
+      return RTCIceGatheringStateGathering;
+    case webrtc::PeerConnectionInterface::kIceGatheringComplete:
+      return RTCIceGatheringStateComplete;
+  }
+}
+
++ (NSString *)stringForIceGatheringState:(RTCIceGatheringState)state {
+  switch (state) {
+    case RTCIceGatheringStateNew:
+      return @"NEW";
+    case RTCIceGatheringStateGathering:
+      return @"GATHERING";
+    case RTCIceGatheringStateComplete:
+      return @"COMPLETE";
+  }
+}
+
++ (webrtc::PeerConnectionInterface::StatsOutputLevel)
+    nativeStatsOutputLevelForLevel:(RTCStatsOutputLevel)level {
+  switch (level) {
+    case RTCStatsOutputLevelStandard:
+      return webrtc::PeerConnectionInterface::kStatsOutputLevelStandard;
+    case RTCStatsOutputLevelDebug:
+      return webrtc::PeerConnectionInterface::kStatsOutputLevelDebug;
+  }
+}
+
+- (rtc::scoped_refptr<webrtc::PeerConnectionInterface>)nativePeerConnection {
+  return _peerConnection;
+}
+
+@end