QuicChromiumClientStream handle Read() after trailers are received but not yet delivered

net/quic/chromium/quic_chromium_client_stream.cc

Index: net/quic/chromium/quic_chromium_client_stream.cc
diff --git a/net/quic/chromium/quic_chromium_client_stream.cc b/net/quic/chromium/quic_chromium_client_stream.cc
index ba3204b873af5d5ba0694ba7d3e2a3d841a14e46..5a3d996fb093f1e857d626442b5de31131d8a80a 100644
--- a/net/quic/chromium/quic_chromium_client_stream.cc
+++ b/net/quic/chromium/quic_chromium_client_stream.cc
@@ -249,7 +249,7 @@ void QuicChromiumClientStream::OnError(int error) {
 }
 
 int QuicChromiumClientStream::Read(IOBuffer* buf, int buf_len) {
-  if (sequencer()->IsClosed())

[xunjieli, 2016/10/07 17:15:35]

This is changed to IsDoneReading() because before returning 0 to caller, we also
want to check if trailers are consumed.

+  if (IsDoneReading())
     return 0;  // EOF
 
   if (!HasBytesToRead())
@@ -258,7 +258,12 @@ int QuicChromiumClientStream::Read(IOBuffer* buf, int buf_len) {
   iovec iov;
   iov.iov_base = buf->data();
   iov.iov_len = buf_len;
-  return Readv(&iov, 1);
+  size_t bytes_read = Readv(&iov, 1);
+  // If no more body bytes and trailers are to be delivered, return
+  // ERR_IO_PENDING now because onDataAvailable() will be called after trailers.
+  if (bytes_read == 0 && !FinishedReadingTrailers())

[mef, 2016/10/07 17:28:31]

What if there are no trailers?

[xunjieli, 2016/10/07 17:39:00]

FinishedReadingTrailers() will return true if there are no trailers.

[mpw, 2016/10/07 17:45:00]

If there are no trailers, FinishedReadingTrailers() will return true, since
fin_received && !trailers_decompressed_.  Perhaps the method should be named
something like FinishedReadingTrailersIfAny(), though I'm not sure that's much
clearer.  At the very least, the doc comment for it should be updated--I'll do
that in a separate CL.

+    return ERR_IO_PENDING;
+  return bytes_read;
 }
 
 bool QuicChromiumClientStream::CanWrite(const CompletionCallback& callback) {
@@ -288,6 +293,8 @@ void QuicChromiumClientStream::NotifyDelegateOfHeadersComplete(
   if (headers_delivered_) {
     MarkTrailersConsumed(decompressed_trailers().length());
     MarkTrailersConsumed();
+    // Post an async task to notify delegate of the FIN flag.
+    NotifyDelegateOfDataAvailableLater();
     net_log_.AddEvent(
         NetLogEventType::QUIC_CHROMIUM_CLIENT_STREAM_READ_RESPONSE_TRAILERS,
         base::Bind(&SpdyHeaderBlockNetLogCallback, &headers));