Reland of Injectable Obj-C video codecs

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

+/*
+ *  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 "WebRTC/RTCVideoCodec.h"
+
+#include "webrtc/modules/include/module_common_types.h"
+
+@implementation RTCRtpFragmentationHeader
+
+@synthesize fragmentationOffset = _fragmentationOffset;
+@synthesize fragmentationLength = _fragmentationLength;
+@synthesize fragmentationTimeDiff = _fragmentationTimeDiff;
+@synthesize fragmentationPlType = _fragmentationPlType;
+
+- (instancetype)initWithFragmentationHeader:
+        (const webrtc::RTPFragmentationHeader *__nullable)fragmentationHeader {

[Chuck, 2017/07/14 14:57:29]

What does nullable mean here for a native pointer? 

+  if (self = [super init]) {
+    if (fragmentationHeader) {
+      int count = fragmentationHeader->fragmentationVectorSize;
+      NSMutableArray *offsets = [NSMutableArray array];
+      NSMutableArray *lengths = [NSMutableArray array];
+      NSMutableArray *timeDiffs = [NSMutableArray array];
+      NSMutableArray *plTypes = [NSMutableArray array];
+      for (int i = 0; i < count; ++i) {
+        [offsets addObject:@(fragmentationHeader->fragmentationOffset[i])];
+        [lengths addObject:@(fragmentationHeader->fragmentationLength[i])];
+        [timeDiffs addObject:@(fragmentationHeader->fragmentationTimeDiff[i])];
+        [plTypes addObject:@(fragmentationHeader->fragmentationPlType[i])];
+      }
+      _fragmentationOffset = [offsets copy];
+      _fragmentationLength = [lengths copy];
+      _fragmentationTimeDiff = [timeDiffs copy];
+      _fragmentationPlType = [plTypes copy];
+    }
+  }
+
+  return self;
+}
+
+- (webrtc::RTPFragmentationHeader *)toCpp {
+  webrtc::RTPFragmentationHeader *fragmentationHeader = new webrtc::RTPFragmentationHeader;

[Chuck, 2017/07/14 14:57:29]

In cases where we return a native pointer we should be using std::unique_ptr,
see example in RTCConfiguration.mm createNativeConfiguration

+  fragmentationHeader->VerifyAndAllocateFragmentationHeader(_fragmentationOffset.count);
+  for (NSUInteger i = 0; i < _fragmentationOffset.count; ++i) {
+    fragmentationHeader->fragmentationOffset[i] = (size_t)_fragmentationOffset[i].unsignedIntValue;
+    fragmentationHeader->fragmentationLength[i] = (size_t)_fragmentationLength[i].unsignedIntValue;
+    fragmentationHeader->fragmentationTimeDiff[i] =
+        (uint16_t)_fragmentationOffset[i].unsignedIntValue;
+    fragmentationHeader->fragmentationPlType[i] = (uint8_t)_fragmentationOffset[i].unsignedIntValue;
+  }
+
+  return fragmentationHeader;
+}
+
+@end