Adding a DCHECK to the QUIC writer's Offset functions, and moving tests around.

Merge internal change: 40692827


Review URL: https://chromiumcodereview.appspot.com/11786009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176935 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 16 insertions, 2 deletions

diff --git a/net/quic/quic_data_writer.cc b/net/quic/quic_data_writer.cc
index 7639566..31ec389 100644
--- a/net/quic/quic_data_writer.cc
+++ b/net/quic/quic_data_writer.cc
@@ -129,6 +129,7 @@ void QuicDataWriter::WriteUint128ToBuffer(uint128 value, char* buffer) {
 }
 
 bool QuicDataWriter::WriteUInt8ToOffset(uint8 value, size_t offset) {
+  DCHECK_LT(offset, capacity_);
   int latched_length = length_;
   length_ = offset;
   bool success = WriteUInt8(value);
@@ -137,6 +138,7 @@ bool QuicDataWriter::WriteUInt8ToOffset(uint8 value, size_t offset) {
 }
 
 bool QuicDataWriter::WriteUInt48ToOffset(uint64 value, size_t offset) {
+  DCHECK_LT(offset, capacity_);
   int latched_length = length_;
   length_ = offset;
   bool success = WriteUInt48(value);
diff --git a/net/quic/quic_data_writer.h b/net/quic/quic_data_writer.h
index c5ecd34..d5f9bb6 100644
--- a/net/quic/quic_data_writer.h
+++ b/net/quic/quic_data_writer.h
@@ -47,7 +47,8 @@ class NET_EXPORT_PRIVATE QuicDataWriter {
   bool WriteStringPiece16(base::StringPiece val);
   bool WriteBytes(const void* data, size_t data_len);
 
-  // Methods for editing the payload at a specific offset.
+  // Methods for editing the payload at a specific offset, where the
+  // offset must be within the writer's capacity.
   // Return true if there is enough space at that offset, false otherwise.
   bool WriteUInt8ToOffset(uint8 value, size_t offset);
   bool WriteUInt48ToOffset(uint64 value, size_t offset);
diff --git a/net/quic/quic_data_writer_test.cc b/net/quic/quic_data_writer_test.cc
index 901dd39..70246a4 100644
--- a/net/quic/quic_data_writer_test.cc
+++ b/net/quic/quic_data_writer_test.cc
@@ -17,7 +17,6 @@ TEST(QuicDataWriterTest, WriteUint8ToOffset) {
   EXPECT_TRUE(writer.WriteUInt8ToOffset(2, 1));
   EXPECT_TRUE(writer.WriteUInt8ToOffset(3, 2));
   EXPECT_TRUE(writer.WriteUInt8ToOffset(4, 3));
-  EXPECT_FALSE(writer.WriteUInt8ToOffset(5, 4));
 
   char* data = writer.take();
 
@@ -29,6 +28,18 @@ TEST(QuicDataWriterTest, WriteUint8ToOffset) {
   delete[] data;
 }
 
+TEST(QuicDataWriterDeathTest, WriteUint8ToOffset) {
+  QuicDataWriter writer(4);
+
+#if !defined(WIN32) && defined(GTEST_HAS_DEATH_TEST)
+#if !defined(DCHECK_ALWAYS_ON)
+  EXPECT_DEBUG_DEATH(writer.WriteUInt8ToOffset(5, 4), "Check failed");
+#else
+  EXPECT_DEATH(writer.WriteUInt8ToOffset(5, 4), "Check failed");
+#endif
+#endif
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace net