From c547e84ec5b935151a8fe9797f283665b660dd24 Mon Sep 17 00:00:00 2001
From: danilchap <danilchap@webrtc.org>
Date: Mon, 10 Apr 2017 01:31:49 -0700
Subject: [PATCH] Allow rtp::Packet::*RawExtension to take 0 as an extension id

BUG=webrtc:7433

Review-Url: https://codereview.webrtc.org/2803623004
Cr-Commit-Position: refs/heads/master@{#17610}
---
 webrtc/modules/rtp_rtcp/source/rtp_packet.cc  |  6 +++++
 .../rtp_rtcp/source/rtp_packet_unittest.cc    | 24 ++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/webrtc/modules/rtp_rtcp/source/rtp_packet.cc b/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
index 0c28092d4c..7a7c45d383 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
@@ -279,12 +279,16 @@ void Packet::SetCsrcs(const std::vector<uint32_t>& csrcs) {
 }
 
 bool Packet::HasRawExtension(int id) const {
+  if (id == ExtensionManager::kInvalidId)
+    return false;
   RTC_DCHECK_GE(id, kMinExtensionId);
   RTC_DCHECK_LE(id, kMaxExtensionId);
   return extension_entries_[id - 1].offset != 0;
 }
 
 rtc::ArrayView<const uint8_t> Packet::GetRawExtension(int id) const {
+  if (id == ExtensionManager::kInvalidId)
+    return nullptr;
   RTC_DCHECK_GE(id, kMinExtensionId);
   RTC_DCHECK_LE(id, kMaxExtensionId);
   const ExtensionInfo& extension = extension_entries_[id - 1];
@@ -303,6 +307,8 @@ bool Packet::SetRawExtension(int id, rtc::ArrayView<const uint8_t> data) {
 }
 
 rtc::ArrayView<uint8_t> Packet::AllocateRawExtension(int id, size_t length) {
+  if (id == ExtensionManager::kInvalidId)
+    return nullptr;
   RTC_DCHECK_GE(id, kMinExtensionId);
   RTC_DCHECK_LE(id, kMaxExtensionId);
   RTC_DCHECK_GE(length, 1);
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_packet_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_packet_unittest.cc
index bdf3aba7b0..b85d98ae09 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_packet_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_packet_unittest.cc
@@ -16,11 +16,12 @@
 #include "webrtc/test/gmock.h"
 #include "webrtc/test/gtest.h"
 
-using testing::ElementsAreArray;
-using testing::make_tuple;
-
 namespace webrtc {
 namespace {
+using ::testing::ElementsAreArray;
+using ::testing::IsEmpty;
+using ::testing::make_tuple;
+
 constexpr int8_t kPayloadType = 100;
 constexpr uint32_t kSsrc = 0x12345678;
 constexpr uint16_t kSeqNum = 88;
@@ -363,4 +364,21 @@ TEST(RtpPacketTest, ParseWithoutExtensionManager) {
   EXPECT_EQ(time_offset, kTimeOffset);
 }
 
+TEST(RtpPacketTest, RawExtensionFunctionsAcceptZeroIdAndReturnFalse) {
+  RtpPacketReceived::ExtensionManager extensions;
+  RtpPacketReceived packet(&extensions);
+  // Use ExtensionManager to set kInvalidId to 0 to demonstrate natural way for
+  // using zero value as a parameter to Packet::*RawExtension functions.
+  const int kInvalidId = extensions.GetId(TransmissionOffset::kId);
+  ASSERT_EQ(kInvalidId, 0);
+
+  ASSERT_TRUE(packet.Parse(kPacket, sizeof(kPacket)));
+
+  EXPECT_FALSE(packet.HasRawExtension(kInvalidId));
+  EXPECT_THAT(packet.GetRawExtension(kInvalidId), IsEmpty());
+  const uint8_t kExtension[] = {'e', 'x', 't'};
+  EXPECT_FALSE(packet.SetRawExtension(kInvalidId, kExtension));
+  EXPECT_THAT(packet.AllocateRawExtension(kInvalidId, 3), IsEmpty());
+}
+
 }  // namespace webrtc