Treat 0 returned from HttpStream::ReadResponseBody correctly.

net/http/http_response_body_drainer_unittest.cc

Index: net/http/http_response_body_drainer_unittest.cc
diff --git a/net/http/http_response_body_drainer_unittest.cc b/net/http/http_response_body_drainer_unittest.cc
index d9b6492a5378ad55986d89375c2a53894e441bc9..eab22aed658f13ba20fdc60622ddca74b55b45a0 100644
--- a/net/http/http_response_body_drainer_unittest.cc
+++ b/net/http/http_response_body_drainer_unittest.cc
@@ -38,7 +38,7 @@ class CloseResultWaiter {
         waiting_for_result_(false) {}
 
   int WaitForResult() {
-    DCHECK(!waiting_for_result_);
+    CHECK(!waiting_for_result_);
     while (!have_result_) {
       waiting_for_result_ = true;
       MessageLoop::current()->Run();
@@ -66,9 +66,12 @@ class MockHttpStream : public HttpStream {
  public:
   MockHttpStream(CloseResultWaiter* result_waiter)
       : result_waiter_(result_waiter),
+        buf_len_(0),
         closed_(false),
         stall_reads_forever_(false),
         num_chunks_(0),
+        is_sync_(false),
+        is_last_chunk_zero_size_(false),
         is_complete_(false),
         ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {}
   virtual ~MockHttpStream() {}
@@ -108,7 +111,7 @@ class MockHttpStream : public HttpStream {
   virtual int ReadResponseBody(IOBuffer* buf, int buf_len,
                                const CompletionCallback& callback) OVERRIDE;
   virtual void Close(bool not_reusable) OVERRIDE {
-    DCHECK(!closed_);
+    CHECK(!closed_);
     closed_ = true;
     result_waiter_->set_result(not_reusable);
   }
@@ -126,11 +129,16 @@ class MockHttpStream : public HttpStream {
   virtual void Drain(HttpNetworkSession*) OVERRIDE {}
 
   // Methods to tweak/observer mock behavior:
-  void StallReadsForever() { stall_reads_forever_ = true; }
+  void set_stall_reads_forever() { stall_reads_forever_ = true; }
 
   void set_num_chunks(int num_chunks) { num_chunks_ = num_chunks; }
 
+  void set_sync() { is_sync_ = true; }
+
+  void set_is_last_chunk_zero_size() { is_last_chunk_zero_size_ = true; }
+
  private:
+  int ReadResponseBodyImpl(IOBuffer* buf, int buf_len);
   void CompleteRead();
 
   bool closed() const { return closed_; }
@@ -138,34 +146,50 @@ class MockHttpStream : public HttpStream {
   CloseResultWaiter* const result_waiter_;
   scoped_refptr<IOBuffer> user_buf_;
   CompletionCallback callback_;
+  int buf_len_;
   bool closed_;
   bool stall_reads_forever_;
   int num_chunks_;
+  bool is_sync_;
+  bool is_last_chunk_zero_size_;
   bool is_complete_;
   base::WeakPtrFactory<MockHttpStream> weak_factory_;
 };
 
-int MockHttpStream::ReadResponseBody(
-    IOBuffer* buf, int buf_len, const CompletionCallback& callback) {
-  DCHECK(!callback.is_null());
-  DCHECK(callback_.is_null());
-  DCHECK(buf);
+int MockHttpStream::ReadResponseBody(IOBuffer* buf,
+                                     int buf_len,
+                                     const CompletionCallback& callback) {
+  CHECK(!callback.is_null());
+  CHECK(callback_.is_null());
+  CHECK(buf);
 
   if (stall_reads_forever_)
     return ERR_IO_PENDING;
 
-  if (num_chunks_ == 0)
+  if (is_complete_)
     return ERR_UNEXPECTED;
 
-  if (buf_len > kMagicChunkSize && num_chunks_ > 1) {
+  if (!is_sync_) {
     user_buf_ = buf;
+    buf_len_ = buf_len;
     callback_ = callback;
     MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&MockHttpStream::CompleteRead, weak_factory_.GetWeakPtr()));
     return ERR_IO_PENDING;
+  } else {
+    return ReadResponseBodyImpl(buf, buf_len);
   }
+}
 
+int MockHttpStream::ReadResponseBodyImpl(IOBuffer* buf, int buf_len) {
+  if (is_last_chunk_zero_size_ && num_chunks_ == 1) {
+    buf_len = 0;
+  } else {
+    if (buf_len > kMagicChunkSize)
+      buf_len = kMagicChunkSize;
+    std::memset(buf->data(), 1, buf_len);
+  }
   num_chunks_--;
   if (!num_chunks_)
     is_complete_ = true;
@@ -174,14 +198,11 @@ int MockHttpStream::ReadResponseBody(
 }
 
 void MockHttpStream::CompleteRead() {
-  CompletionCallback callback = callback_;
-  std::memset(user_buf_->data(), 1, kMagicChunkSize);
+  int result = ReadResponseBodyImpl(user_buf_, buf_len_);
   user_buf_ = NULL;
+  CompletionCallback callback = callback_;
   callback_.Reset();
-  num_chunks_--;
-  if (!num_chunks_)
-    is_complete_ = true;
-  callback.Run(kMagicChunkSize);
+  callback.Run(result);
 }
 
 class HttpResponseBodyDrainerTest : public testing::Test {
@@ -213,8 +234,16 @@ class HttpResponseBodyDrainerTest : public testing::Test {
   HttpResponseBodyDrainer* const drainer_;  // Deletes itself.
 };
 
-TEST_F(HttpResponseBodyDrainerTest, DrainBodySyncOK) {
+TEST_F(HttpResponseBodyDrainerTest, DrainBodySyncSingleOK) {
   mock_stream_->set_num_chunks(1);
+  mock_stream_->set_sync();
+  drainer_->Start(session_);
+  EXPECT_FALSE(result_waiter_.WaitForResult());
+}
+
+TEST_F(HttpResponseBodyDrainerTest, DrainBodySyncOK) {
+  mock_stream_->set_num_chunks(3);
+  mock_stream_->set_sync();
   drainer_->Start(session_);
   EXPECT_FALSE(result_waiter_.WaitForResult());
 }
@@ -225,6 +254,24 @@ TEST_F(HttpResponseBodyDrainerTest, DrainBodyAsyncOK) {
   EXPECT_FALSE(result_waiter_.WaitForResult());
 }
 
+// Test the case when the final chunk is 0 bytes. This can happen when
+// the final 0-byte chunk of a chunk-encoded http response is read in a last
+// call to ReadResponseBody, after all data were returned from HttpStream.
+TEST_F(HttpResponseBodyDrainerTest, DrainBodyAsyncEmptyChunk) {
+  mock_stream_->set_num_chunks(4);
+  mock_stream_->set_is_last_chunk_zero_size();
+  drainer_->Start(session_);
+  EXPECT_FALSE(result_waiter_.WaitForResult());
+}
+
+TEST_F(HttpResponseBodyDrainerTest, DrainBodySyncEmptyChunk) {
+  mock_stream_->set_num_chunks(4);
+  mock_stream_->set_sync();
+  mock_stream_->set_is_last_chunk_zero_size();
+  drainer_->Start(session_);
+  EXPECT_FALSE(result_waiter_.WaitForResult());
+}
+
 TEST_F(HttpResponseBodyDrainerTest, DrainBodySizeEqualsDrainBuffer) {
   mock_stream_->set_num_chunks(
       HttpResponseBodyDrainer::kDrainBodyBufferSize / kMagicChunkSize);
@@ -234,14 +281,14 @@ TEST_F(HttpResponseBodyDrainerTest, DrainBodySizeEqualsDrainBuffer) {
 
 TEST_F(HttpResponseBodyDrainerTest, DrainBodyTimeOut) {
   mock_stream_->set_num_chunks(2);
-  mock_stream_->StallReadsForever();
+  mock_stream_->set_stall_reads_forever();
   drainer_->Start(session_);
   EXPECT_TRUE(result_waiter_.WaitForResult());
 }
 
 TEST_F(HttpResponseBodyDrainerTest, CancelledBySession) {
   mock_stream_->set_num_chunks(2);
-  mock_stream_->StallReadsForever();
+  mock_stream_->set_stall_reads_forever();
   drainer_->Start(session_);
   // HttpNetworkSession should delete |drainer_|.
 }