Obj-C SDK Cleanup

This CL separates the files under sdk/objc into logical directories, replacing
the previous file layout under Framework/.

A long term goal is to have some system set up to generate the files under
sdk/objc/api (the PeerConnection API wrappers) from the C++ code. In the shorter
term the goal is to abstract out shared concepts from these classes in order to
make them as uniform as possible.

The separation into base/, components/, and helpers/ are to differentiate between
the base layer's common protocols, various utilities and the actual platform
specific components.

The old directory layout that resembled a framework's internal layout is not
necessary, since it is generated by the framework target when building it.

Bug: webrtc:9627
Change-Id: Ib084fd83f050ae980649ca99e841f4fb0580bd8f
Reviewed-on: https://webrtc-review.googlesource.com/94142
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24493}

sdk/objc/helpers/AVCaptureSession+DevicePosition.h

@@ -0,0 +1,23 @@
+/*
+ *  Copyright 2017 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 <AVFoundation/AVFoundation.h>
+#import <CoreMedia/CoreMedia.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface AVCaptureSession (DevicePosition)
+
+// Check the image's EXIF for the camera the image came from.
++ (AVCaptureDevicePosition)devicePositionForSampleBuffer:(CMSampleBufferRef)sampleBuffer;
+
+@end
+
+NS_ASSUME_NONNULL_END

sdk/objc/helpers/AVCaptureSession+DevicePosition.mm

@@ -0,0 +1,51 @@
+/*
+ *  Copyright 2017 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 "AVCaptureSession+DevicePosition.h"
+
+BOOL CFStringContainsString(CFStringRef theString, CFStringRef stringToFind) {
+  return CFStringFindWithOptions(theString,
+                                 stringToFind,
+                                 CFRangeMake(0, CFStringGetLength(theString)),
+                                 kCFCompareCaseInsensitive,
+                                 nil);
+}
+
+@implementation AVCaptureSession (DevicePosition)
+
++ (AVCaptureDevicePosition)devicePositionForSampleBuffer:(CMSampleBufferRef)sampleBuffer {
+  // Check the image's EXIF for the camera the image came from.
+  AVCaptureDevicePosition cameraPosition = AVCaptureDevicePositionUnspecified;
+  CFDictionaryRef attachments = CMCopyDictionaryOfAttachments(
+      kCFAllocatorDefault, sampleBuffer, kCMAttachmentMode_ShouldPropagate);
+  if (attachments) {
+    int size = CFDictionaryGetCount(attachments);
+    if (size > 0) {
+      CFDictionaryRef cfExifDictVal = nil;
+      if (CFDictionaryGetValueIfPresent(
+              attachments, (const void *)CFSTR("{Exif}"), (const void **)&cfExifDictVal)) {
+        CFStringRef cfLensModelStrVal;
+        if (CFDictionaryGetValueIfPresent(cfExifDictVal,
+                                          (const void *)CFSTR("LensModel"),
+                                          (const void **)&cfLensModelStrVal)) {
+          if (CFStringContainsString(cfLensModelStrVal, CFSTR("front"))) {
+            cameraPosition = AVCaptureDevicePositionFront;
+          } else if (CFStringContainsString(cfLensModelStrVal, CFSTR("back"))) {
+            cameraPosition = AVCaptureDevicePositionBack;
+          }
+        }
+      }
+    }
+    CFRelease(attachments);
+  }
+  return cameraPosition;
+}
+
+@end

sdk/objc/helpers/NSString+StdString.h

@@ -0,0 +1,26 @@
+/*
+ *  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 <Foundation/Foundation.h>
+
+#include <string>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface NSString (StdString)
+
+@property(nonatomic, readonly) std::string stdString;
+
++ (std::string)stdStringForString:(NSString *)nsString;
++ (NSString *)stringForStdString:(const std::string &)stdString;
+
+@end
+
+NS_ASSUME_NONNULL_END

sdk/objc/helpers/NSString+StdString.mm

@@ -0,0 +1,33 @@
+/*
+ *  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 "NSString+StdString.h"
+
+@implementation NSString (StdString)
+
+- (std::string)stdString {
+  return [NSString stdStringForString:self];
+}
+
++ (std::string)stdStringForString:(NSString *)nsString {
+  NSData *charData = [nsString dataUsingEncoding:NSUTF8StringEncoding];
+  return std::string(reinterpret_cast<const char *>(charData.bytes),
+                     charData.length);
+}
+
++ (NSString *)stringForStdString:(const std::string&)stdString {
+  // std::string may contain null termination character so we construct
+  // using length.
+  return [[NSString alloc] initWithBytes:stdString.data()
+                                  length:stdString.length()
+                                encoding:NSUTF8StringEncoding];
+}
+
+@end

sdk/objc/helpers/RTCCameraPreviewView.h

@@ -0,0 +1,30 @@
+/*
+ *  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 <Foundation/Foundation.h>
+#import <UIKit/UIKit.h>
+
+#import "RTCMacros.h"
+
+@class AVCaptureSession;
+
+/** RTCCameraPreviewView is a view that renders local video from an
+ *  AVCaptureSession.
+ */
+RTC_EXPORT
+@interface RTCCameraPreviewView : UIView
+
+/** The capture session being rendered in the view. Capture session
+ *  is assigned to AVCaptureVideoPreviewLayer async in the same
+ *  queue that the AVCaptureSession is started/stopped.
+ */
+@property(nonatomic, strong) AVCaptureSession* captureSession;
+
+@end

sdk/objc/helpers/RTCCameraPreviewView.m

@@ -0,0 +1,120 @@
+/*
+ *  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 "RTCCameraPreviewView.h"
+
+#import <AVFoundation/AVFoundation.h>
+#import <UIKit/UIKit.h>
+
+#import "RTCDispatcher+Private.h"
+
+@implementation RTCCameraPreviewView
+
+@synthesize captureSession = _captureSession;
+
++ (Class)layerClass {
+  return [AVCaptureVideoPreviewLayer class];
+}
+
+- (instancetype)initWithFrame:(CGRect)aRect {
+  self = [super initWithFrame:aRect];
+  if (self) {
+    [self addOrientationObserver];
+  }
+  return self;
+}
+
+- (instancetype)initWithCoder:(NSCoder*)aDecoder {
+  self = [super initWithCoder:aDecoder];
+  if (self) {
+    [self addOrientationObserver];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [self removeOrientationObserver];
+}
+
+- (void)setCaptureSession:(AVCaptureSession *)captureSession {
+  if (_captureSession == captureSession) {
+    return;
+  }
+  [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeMain
+                               block:^{
+    _captureSession = captureSession;
+    AVCaptureVideoPreviewLayer *previewLayer = [self previewLayer];
+    [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
+                                 block:^{
+      previewLayer.session = captureSession;
+      [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeMain
+                               block:^{
+        [self setCorrectVideoOrientation];
+      }];
+    }];
+  }];
+}
+
+- (void)layoutSubviews {
+  [super layoutSubviews];
+
+  // Update the video orientation based on the device orientation.
+  [self setCorrectVideoOrientation];
+}
+
+-(void)orientationChanged:(NSNotification *)notification {
+  [self setCorrectVideoOrientation];
+}
+
+- (void)setCorrectVideoOrientation {
+  // Get current device orientation.
+  UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
+  AVCaptureVideoPreviewLayer *previewLayer = [self previewLayer];
+
+  // First check if we are allowed to set the video orientation.
+  if (previewLayer.connection.isVideoOrientationSupported) {
+    // Set the video orientation based on device orientation.
+    if (deviceOrientation == UIInterfaceOrientationPortraitUpsideDown) {
+      previewLayer.connection.videoOrientation =
+          AVCaptureVideoOrientationPortraitUpsideDown;
+    } else if (deviceOrientation == UIInterfaceOrientationLandscapeRight) {
+      previewLayer.connection.videoOrientation =
+          AVCaptureVideoOrientationLandscapeRight;
+    } else if (deviceOrientation == UIInterfaceOrientationLandscapeLeft) {
+      previewLayer.connection.videoOrientation =
+          AVCaptureVideoOrientationLandscapeLeft;
+    } else if (deviceOrientation == UIInterfaceOrientationPortrait) {
+      previewLayer.connection.videoOrientation =
+          AVCaptureVideoOrientationPortrait;
+    }
+    // If device orientation switches to FaceUp or FaceDown, don't change video orientation.
+  }
+}
+
+#pragma mark - Private
+
+- (void)addOrientationObserver {
+  [[NSNotificationCenter defaultCenter] addObserver:self
+                                            selector:@selector(orientationChanged:)
+                                                name:UIDeviceOrientationDidChangeNotification
+                                              object:nil];
+}
+
+- (void)removeOrientationObserver {
+  [[NSNotificationCenter defaultCenter] removeObserver:self
+                                                  name:UIDeviceOrientationDidChangeNotification
+                                                object:nil];
+}
+
+- (AVCaptureVideoPreviewLayer *)previewLayer {
+  return (AVCaptureVideoPreviewLayer *)self.layer;
+}
+
+@end

sdk/objc/helpers/RTCDispatcher+Private.h

@@ -0,0 +1,17 @@
+/*
+ *  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 "RTCDispatcher.h"
+
+@interface RTCDispatcher ()
+
++ (dispatch_queue_t)dispatchQueueForType:(RTCDispatcherQueueType)dispatchType;
+
+@end

sdk/objc/helpers/RTCDispatcher.h

@@ -0,0 +1,44 @@
+/*
+ *  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 <Foundation/Foundation.h>
+
+#import "RTCMacros.h"
+
+typedef NS_ENUM(NSInteger, RTCDispatcherQueueType) {
+  // Main dispatcher queue.
+  RTCDispatcherTypeMain,
+  // Used for starting/stopping AVCaptureSession, and assigning
+  // capture session to AVCaptureVideoPreviewLayer.
+  RTCDispatcherTypeCaptureSession,
+  // Used for operations on AVAudioSession.
+  RTCDispatcherTypeAudioSession,
+};
+
+/** Dispatcher that asynchronously dispatches blocks to a specific
+ *  shared dispatch queue.
+ */
+RTC_EXPORT
+@interface RTCDispatcher : NSObject
+
+- (instancetype)init NS_UNAVAILABLE;
+
+/** Dispatch the block asynchronously on the queue for dispatchType.
+ *  @param dispatchType The queue type to dispatch on.
+ *  @param block The block to dispatch asynchronously.
+ */
++ (void)dispatchAsyncOnType:(RTCDispatcherQueueType)dispatchType block:(dispatch_block_t)block;
+
+/** Returns YES if run on queue for the dispatchType otherwise NO.
+ *  Useful for asserting that a method is run on a correct queue.
+ */
++ (BOOL)isOnQueueForType:(RTCDispatcherQueueType)dispatchType;
+
+@end

sdk/objc/helpers/RTCDispatcher.m

@@ -0,0 +1,60 @@
+/*
+ *  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 "RTCDispatcher+Private.h"
+
+static dispatch_queue_t kAudioSessionQueue = nil;
+static dispatch_queue_t kCaptureSessionQueue = nil;
+
+@implementation RTCDispatcher
+
++ (void)initialize {
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    kAudioSessionQueue = dispatch_queue_create(
+        "org.webrtc.RTCDispatcherAudioSession",
+        DISPATCH_QUEUE_SERIAL);
+    kCaptureSessionQueue = dispatch_queue_create(
+        "org.webrtc.RTCDispatcherCaptureSession",
+        DISPATCH_QUEUE_SERIAL);
+  });
+}
+
++ (void)dispatchAsyncOnType:(RTCDispatcherQueueType)dispatchType
+                      block:(dispatch_block_t)block {
+  dispatch_queue_t queue = [self dispatchQueueForType:dispatchType];
+  dispatch_async(queue, block);
+}
+
++ (BOOL)isOnQueueForType:(RTCDispatcherQueueType)dispatchType {
+  dispatch_queue_t targetQueue = [self dispatchQueueForType:dispatchType];
+  const char* targetLabel = dispatch_queue_get_label(targetQueue);
+  const char* currentLabel = dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL);
+
+  NSAssert(strlen(targetLabel) > 0, @"Label is required for the target queue.");
+  NSAssert(strlen(currentLabel) > 0, @"Label is required for the current queue.");
+
+  return strcmp(targetLabel, currentLabel) == 0;
+}
+
+#pragma mark - Private
+
++ (dispatch_queue_t)dispatchQueueForType:(RTCDispatcherQueueType)dispatchType {
+  switch (dispatchType) {
+    case RTCDispatcherTypeMain:
+      return dispatch_get_main_queue();
+    case RTCDispatcherTypeCaptureSession:
+      return kCaptureSessionQueue;
+    case RTCDispatcherTypeAudioSession:
+      return kAudioSessionQueue;
+  }
+}
+
+@end

sdk/objc/helpers/RTCUIApplicationStatusObserver.h

@@ -0,0 +1,25 @@
+/*
+ *  Copyright 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.
+ */
+
+#if defined(WEBRTC_IOS)
+
+#import <Foundation/Foundation.h>
+
+NS_EXTENSION_UNAVAILABLE_IOS("Application status not available in app extensions.")
+@interface RTCUIApplicationStatusObserver : NSObject
+
++ (instancetype)sharedInstance;
++ (void)prepareForUse;
+
+- (BOOL)isApplicationActive;
+
+@end
+
+#endif  // WEBRTC_IOS

sdk/objc/helpers/RTCUIApplicationStatusObserver.m

@@ -0,0 +1,114 @@
+/*
+ *  Copyright 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 "RTCUIApplicationStatusObserver.h"
+
+#if defined(WEBRTC_IOS)
+
+#import <UIKit/UIKit.h>
+
+#include "rtc_base/checks.h"
+
+@interface RTCUIApplicationStatusObserver ()
+
+@property(nonatomic, assign) BOOL initialized;
+@property(nonatomic, assign) UIApplicationState state;
+
+@end
+
+@implementation RTCUIApplicationStatusObserver {
+  BOOL _initialized;
+  dispatch_block_t _initializeBlock;
+  dispatch_semaphore_t _waitForInitializeSemaphore;
+  UIApplicationState _state;
+
+  id<NSObject> _activeObserver;
+  id<NSObject> _backgroundObserver;
+}
+
+@synthesize initialized = _initialized;
+@synthesize state = _state;
+
++ (instancetype)sharedInstance {
+  static id sharedInstance;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    sharedInstance = [[self alloc] init];
+  });
+
+  return sharedInstance;
+}
+
+// Method to make sure observers are added and the initialization block is
+// scheduled to run on the main queue.
++ (void)prepareForUse {
+  __unused RTCUIApplicationStatusObserver *observer = [self sharedInstance];
+}
+
+- (id)init {
+  if (self = [super init]) {
+    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
+    __weak RTCUIApplicationStatusObserver *weakSelf = self;
+    _activeObserver = [center addObserverForName:UIApplicationDidBecomeActiveNotification
+                                          object:nil
+                                           queue:[NSOperationQueue mainQueue]
+                                      usingBlock:^(NSNotification *note) {
+                                        weakSelf.state =
+                                            [UIApplication sharedApplication].applicationState;
+                                      }];
+
+    _backgroundObserver = [center addObserverForName:UIApplicationDidEnterBackgroundNotification
+                                              object:nil
+                                               queue:[NSOperationQueue mainQueue]
+                                          usingBlock:^(NSNotification *note) {
+                                            weakSelf.state =
+                                                [UIApplication sharedApplication].applicationState;
+                                          }];
+
+    _waitForInitializeSemaphore = dispatch_semaphore_create(1);
+    _initialized = NO;
+    _initializeBlock = dispatch_block_create(DISPATCH_BLOCK_INHERIT_QOS_CLASS, ^{
+      weakSelf.state = [UIApplication sharedApplication].applicationState;
+      weakSelf.initialized = YES;
+    });
+
+    dispatch_async(dispatch_get_main_queue(), _initializeBlock);
+  }
+
+  return self;
+}
+
+- (void)dealloc {
+  NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
+  [center removeObserver:_activeObserver];
+  [center removeObserver:_backgroundObserver];
+}
+
+- (BOOL)isApplicationActive {
+  // NOTE: The function `dispatch_block_wait` can only legally be called once.
+  // Because of this, if several threads call the `isApplicationActive` method before
+  // the `_initializeBlock` has been executed, instead of multiple threads calling
+  // `dispatch_block_wait`, the other threads need to wait for the first waiting thread
+  // instead.
+  if (!_initialized) {
+    dispatch_semaphore_wait(_waitForInitializeSemaphore, DISPATCH_TIME_FOREVER);
+    if (!_initialized) {
+      long ret = dispatch_block_wait(_initializeBlock,
+                                     dispatch_time(DISPATCH_TIME_NOW, 10.0 * NSEC_PER_SEC));
+      RTC_DCHECK_EQ(ret, 0);
+    }
+    dispatch_semaphore_signal(_waitForInitializeSemaphore);
+  }
+  return _state == UIApplicationStateActive;
+}
+
+@end
+
+#endif  // WEBRTC_IOS

sdk/objc/helpers/UIDevice+RTCDevice.h

@@ -0,0 +1,81 @@
+/*
+ *  Copyright 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.
+ */
+
+#import <UIKit/UIKit.h>
+
+typedef NS_ENUM(NSInteger, RTCDeviceType) {
+  RTCDeviceTypeUnknown,
+  RTCDeviceTypeIPhone1G,
+  RTCDeviceTypeIPhone3G,
+  RTCDeviceTypeIPhone3GS,
+  RTCDeviceTypeIPhone4,
+  RTCDeviceTypeIPhone4Verizon,
+  RTCDeviceTypeIPhone4S,
+  RTCDeviceTypeIPhone5GSM,
+  RTCDeviceTypeIPhone5GSM_CDMA,
+  RTCDeviceTypeIPhone5CGSM,
+  RTCDeviceTypeIPhone5CGSM_CDMA,
+  RTCDeviceTypeIPhone5SGSM,
+  RTCDeviceTypeIPhone5SGSM_CDMA,
+  RTCDeviceTypeIPhone6Plus,
+  RTCDeviceTypeIPhone6,
+  RTCDeviceTypeIPhone6S,
+  RTCDeviceTypeIPhone6SPlus,
+  RTCDeviceTypeIPhone7,
+  RTCDeviceTypeIPhone7Plus,
+  RTCDeviceTypeIPhoneSE,
+  RTCDeviceTypeIPhone8,
+  RTCDeviceTypeIPhone8Plus,
+  RTCDeviceTypeIPhoneX,
+  RTCDeviceTypeIPodTouch1G,
+  RTCDeviceTypeIPodTouch2G,
+  RTCDeviceTypeIPodTouch3G,
+  RTCDeviceTypeIPodTouch4G,
+  RTCDeviceTypeIPodTouch5G,
+  RTCDeviceTypeIPodTouch6G,
+  RTCDeviceTypeIPad,
+  RTCDeviceTypeIPad2Wifi,
+  RTCDeviceTypeIPad2GSM,
+  RTCDeviceTypeIPad2CDMA,
+  RTCDeviceTypeIPad2Wifi2,
+  RTCDeviceTypeIPadMiniWifi,
+  RTCDeviceTypeIPadMiniGSM,
+  RTCDeviceTypeIPadMiniGSM_CDMA,
+  RTCDeviceTypeIPad3Wifi,
+  RTCDeviceTypeIPad3GSM_CDMA,
+  RTCDeviceTypeIPad3GSM,
+  RTCDeviceTypeIPad4Wifi,
+  RTCDeviceTypeIPad4GSM,
+  RTCDeviceTypeIPad4GSM_CDMA,
+  RTCDeviceTypeIPad5,
+  RTCDeviceTypeIPad6,
+  RTCDeviceTypeIPadAirWifi,
+  RTCDeviceTypeIPadAirCellular,
+  RTCDeviceTypeIPadAirWifiCellular,
+  RTCDeviceTypeIPadAir2,
+  RTCDeviceTypeIPadMini2GWifi,
+  RTCDeviceTypeIPadMini2GCellular,
+  RTCDeviceTypeIPadMini2GWifiCellular,
+  RTCDeviceTypeIPadMini3,
+  RTCDeviceTypeIPadMini4,
+  RTCDeviceTypeIPadPro9Inch,
+  RTCDeviceTypeIPadPro12Inch,
+  RTCDeviceTypeIPadPro12Inch2,
+  RTCDeviceTypeIPadPro10Inch,
+  RTCDeviceTypeSimulatori386,
+  RTCDeviceTypeSimulatorx86_64,
+};
+
+@interface UIDevice (RTCDevice)
+
++ (RTCDeviceType)deviceType;
++ (BOOL)isIOS11OrLater;
+
+@end

sdk/objc/helpers/UIDevice+RTCDevice.mm

@@ -0,0 +1,120 @@
+/*
+ *  Copyright 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.
+ */
+
+#import "UIDevice+RTCDevice.h"
+
+#import <sys/utsname.h>
+#include <memory>
+
+@implementation UIDevice (RTCDevice)
+
++ (RTCDeviceType)deviceType {
+  NSDictionary *machineNameToType = @{
+    @"iPhone1,1": @(RTCDeviceTypeIPhone1G),
+    @"iPhone1,2": @(RTCDeviceTypeIPhone3G),
+    @"iPhone2,1": @(RTCDeviceTypeIPhone3GS),
+    @"iPhone3,1": @(RTCDeviceTypeIPhone4),
+    @"iPhone3,2": @(RTCDeviceTypeIPhone4),
+    @"iPhone3,3": @(RTCDeviceTypeIPhone4Verizon),
+    @"iPhone4,1": @(RTCDeviceTypeIPhone4S),
+    @"iPhone5,1": @(RTCDeviceTypeIPhone5GSM),
+    @"iPhone5,2": @(RTCDeviceTypeIPhone5GSM_CDMA),
+    @"iPhone5,3": @(RTCDeviceTypeIPhone5CGSM),
+    @"iPhone5,4": @(RTCDeviceTypeIPhone5CGSM_CDMA),
+    @"iPhone6,1": @(RTCDeviceTypeIPhone5SGSM),
+    @"iPhone6,2": @(RTCDeviceTypeIPhone5SGSM_CDMA),
+    @"iPhone7,1": @(RTCDeviceTypeIPhone6Plus),
+    @"iPhone7,2": @(RTCDeviceTypeIPhone6),
+    @"iPhone8,1": @(RTCDeviceTypeIPhone6S),
+    @"iPhone8,2": @(RTCDeviceTypeIPhone6SPlus),
+    @"iPhone8,4": @(RTCDeviceTypeIPhoneSE),
+    @"iPhone9,1": @(RTCDeviceTypeIPhone7),
+    @"iPhone9,2": @(RTCDeviceTypeIPhone7Plus),
+    @"iPhone9,3": @(RTCDeviceTypeIPhone7),
+    @"iPhone9,4": @(RTCDeviceTypeIPhone7Plus),
+    @"iPhone10,1": @(RTCDeviceTypeIPhone8),
+    @"iPhone10,2": @(RTCDeviceTypeIPhone8Plus),
+    @"iPhone10,3": @(RTCDeviceTypeIPhoneX),
+    @"iPhone10,4": @(RTCDeviceTypeIPhone8),
+    @"iPhone10,5": @(RTCDeviceTypeIPhone8Plus),
+    @"iPhone10,6": @(RTCDeviceTypeIPhoneX),
+    @"iPod1,1": @(RTCDeviceTypeIPodTouch1G),
+    @"iPod2,1": @(RTCDeviceTypeIPodTouch2G),
+    @"iPod3,1": @(RTCDeviceTypeIPodTouch3G),
+    @"iPod4,1": @(RTCDeviceTypeIPodTouch4G),
+    @"iPod5,1": @(RTCDeviceTypeIPodTouch5G),
+    @"iPod7,1": @(RTCDeviceTypeIPodTouch6G),
+    @"iPad1,1": @(RTCDeviceTypeIPad),
+    @"iPad2,1": @(RTCDeviceTypeIPad2Wifi),
+    @"iPad2,2": @(RTCDeviceTypeIPad2GSM),
+    @"iPad2,3": @(RTCDeviceTypeIPad2CDMA),
+    @"iPad2,4": @(RTCDeviceTypeIPad2Wifi2),
+    @"iPad2,5": @(RTCDeviceTypeIPadMiniWifi),
+    @"iPad2,6": @(RTCDeviceTypeIPadMiniGSM),
+    @"iPad2,7": @(RTCDeviceTypeIPadMiniGSM_CDMA),
+    @"iPad3,1": @(RTCDeviceTypeIPad3Wifi),
+    @"iPad3,2": @(RTCDeviceTypeIPad3GSM_CDMA),
+    @"iPad3,3": @(RTCDeviceTypeIPad3GSM),
+    @"iPad3,4": @(RTCDeviceTypeIPad4Wifi),
+    @"iPad3,5": @(RTCDeviceTypeIPad4GSM),
+    @"iPad3,6": @(RTCDeviceTypeIPad4GSM_CDMA),
+    @"iPad4,1": @(RTCDeviceTypeIPadAirWifi),
+    @"iPad4,2": @(RTCDeviceTypeIPadAirCellular),
+    @"iPad4,3": @(RTCDeviceTypeIPadAirWifiCellular),
+    @"iPad4,4": @(RTCDeviceTypeIPadMini2GWifi),
+    @"iPad4,5": @(RTCDeviceTypeIPadMini2GCellular),
+    @"iPad4,6": @(RTCDeviceTypeIPadMini2GWifiCellular),
+    @"iPad4,7": @(RTCDeviceTypeIPadMini3),
+    @"iPad4,8": @(RTCDeviceTypeIPadMini3),
+    @"iPad4,9": @(RTCDeviceTypeIPadMini3),
+    @"iPad5,1": @(RTCDeviceTypeIPadMini4),
+    @"iPad5,2": @(RTCDeviceTypeIPadMini4),
+    @"iPad5,3": @(RTCDeviceTypeIPadAir2),
+    @"iPad5,4": @(RTCDeviceTypeIPadAir2),
+    @"iPad6,3": @(RTCDeviceTypeIPadPro9Inch),
+    @"iPad6,4": @(RTCDeviceTypeIPadPro9Inch),
+    @"iPad6,7": @(RTCDeviceTypeIPadPro12Inch),
+    @"iPad6,8": @(RTCDeviceTypeIPadPro12Inch),
+    @"iPad6,11": @(RTCDeviceTypeIPad5),
+    @"iPad6,12": @(RTCDeviceTypeIPad5),
+    @"iPad7,1": @(RTCDeviceTypeIPadPro12Inch2),
+    @"iPad7,2": @(RTCDeviceTypeIPadPro12Inch2),
+    @"iPad7,3": @(RTCDeviceTypeIPadPro10Inch),
+    @"iPad7,4": @(RTCDeviceTypeIPadPro10Inch),
+    @"iPad7,5": @(RTCDeviceTypeIPad6),
+    @"iPad7,6": @(RTCDeviceTypeIPad6),
+    @"i386": @(RTCDeviceTypeSimulatori386),
+    @"x86_64": @(RTCDeviceTypeSimulatorx86_64),
+  };
+
+  RTCDeviceType deviceType = RTCDeviceTypeUnknown;
+  NSNumber *typeNumber = machineNameToType[[self machineName]];
+  if (typeNumber) {
+    deviceType = static_cast<RTCDeviceType>(typeNumber.integerValue);
+  }
+  return deviceType;
+}
+
++ (NSString *)machineName {
+  struct utsname systemInfo;
+  uname(&systemInfo);
+  return [[NSString alloc] initWithCString:systemInfo.machine
+                                  encoding:NSUTF8StringEncoding];
+}
+
++ (double)currentDeviceSystemVersion {
+  return [self currentDevice].systemVersion.doubleValue;
+}
+
++ (BOOL)isIOS11OrLater {
+  return [self currentDeviceSystemVersion] >= 11.0;
+}
+
+@end

sdk/objc/helpers/noop.mm

@@ -0,0 +1,13 @@
+/*
+ *  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.
+ */
+
+// This file is only needed to make ninja happy on some platforms.
+// On some platforms it is not possible to link an rtc_static_library
+// without any source file listed in the GN target.

sdk/objc/helpers/scoped_cftyperef.h

@@ -0,0 +1,116 @@
+/*
+ *  Copyright (c) 2017 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 SDK_OBJC_HELPERS_SCOPED_CFTYPEREF_H_
+#define SDK_OBJC_HELPERS_SCOPED_CFTYPEREF_H_
+
+#include <CoreFoundation/CoreFoundation.h>
+namespace rtc {
+
+// RETAIN: ScopedTypeRef should retain the object when it takes
+// ownership.
+// ASSUME: Assume the object already has already been retained.
+// ScopedTypeRef takes over ownership.
+enum class RetainPolicy { RETAIN, ASSUME };
+
+namespace internal {
+template <typename T>
+struct CFTypeRefTraits {
+  static T InvalidValue() { return nullptr; }
+  static void Release(T ref) { CFRelease(ref); }
+  static T Retain(T ref) {
+    CFRetain(ref);
+    return ref;
+  }
+};
+
+template <typename T, typename Traits>
+class ScopedTypeRef {
+ public:
+  ScopedTypeRef() : ptr_(Traits::InvalidValue()) {}
+  explicit ScopedTypeRef(T ptr) : ptr_(ptr) {}
+  ScopedTypeRef(T ptr, RetainPolicy policy) : ScopedTypeRef(ptr) {
+    if (ptr_ && policy == RetainPolicy::RETAIN)
+      Traits::Retain(ptr_);
+  }
+
+  ScopedTypeRef(const ScopedTypeRef<T, Traits>& rhs) : ptr_(rhs.ptr_) {
+    if (ptr_)
+      ptr_ = Traits::Retain(ptr_);
+  }
+
+  ~ScopedTypeRef() {
+    if (ptr_) {
+      Traits::Release(ptr_);
+    }
+  }
+
+  T get() const { return ptr_; }
+  T operator->() const { return ptr_; }
+  explicit operator bool() const { return ptr_; }
+
+  bool operator!() const { return !ptr_; }
+
+  ScopedTypeRef& operator=(const T& rhs) {
+    if (ptr_)
+      Traits::Release(ptr_);
+    ptr_ = rhs;
+    return *this;
+  }
+
+  ScopedTypeRef& operator=(const ScopedTypeRef<T, Traits>& rhs) {
+    reset(rhs.get(), RetainPolicy::RETAIN);
+    return *this;
+  }
+
+  // This is intended to take ownership of objects that are
+  // created by pass-by-pointer initializers.
+  T* InitializeInto() {
+    RTC_DCHECK(!ptr_);
+    return &ptr_;
+  }
+
+  void reset(T ptr, RetainPolicy policy = RetainPolicy::ASSUME) {
+    if (ptr && policy == RetainPolicy::RETAIN)
+      Traits::Retain(ptr);
+    if (ptr_)
+      Traits::Release(ptr_);
+    ptr_ = ptr;
+  }
+
+  T release() {
+    T temp = ptr_;
+    ptr_ = Traits::InvalidValue();
+    return temp;
+  }
+
+ private:
+  T ptr_;
+};
+}  // namespace internal
+
+template <typename T>
+using ScopedCFTypeRef =
+    internal::ScopedTypeRef<T, internal::CFTypeRefTraits<T>>;
+
+template <typename T>
+static ScopedCFTypeRef<T> AdoptCF(T cftype) {
+  return ScopedCFTypeRef<T>(cftype, RetainPolicy::RETAIN);
+}
+
+template <typename T>
+static ScopedCFTypeRef<T> ScopedCF(T cftype) {
+  return ScopedCFTypeRef<T>(cftype);
+}
+
+}  // namespace rtc
+
+#endif  // SDK_OBJC_HELPERS_SCOPED_CFTYPEREF_H_