Add a new SpdyStream::Delegate method to handle trailers

net/spdy/spdy_stream.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_SPDY_SPDY_STREAM_H_
 #define NET_SPDY_SPDY_STREAM_H_
 
 #include <deque>
 #include <string>
 #include <vector>
@@ skipping 36 matching lines @@
 };
 
 // Passed to some SpdyStream functions to indicate whether there's
 // more data to send.
 enum SpdySendStatus {
   MORE_DATA_TO_SEND,
   NO_MORE_DATA_TO_SEND
 };
 
 // Returned by SpdyStream::OnResponseHeadersUpdated() to indicate
 // whether the current response headers are complete or not.

[Ryan Hamilton, 2015/08/10 17:23:25]

Please update this comment to reflect the meaning of the new TRAILERS_RECEIVED
state. Also, it would be great to explain here (or elsewhere) when it's possible
to received HEADERS. It looks like only before any DATA or after all DATA. Is
that right?

[xunjieli, 2015/08/10 20:31:07]

Done. Good catch! I also updated comments below.

 enum SpdyResponseHeadersStatus {
   RESPONSE_HEADERS_ARE_INCOMPLETE,
-  RESPONSE_HEADERS_ARE_COMPLETE
+  RESPONSE_HEADERS_ARE_COMPLETE,
+  TRAILERS_RECEIVED,
 };
 
 // The SpdyStream is used by the SpdySession to represent each stream known
 // on the SpdySession.  This class provides interfaces for SpdySession to use.
 // Streams can be created either by the client or by the server.  When they
 // are initiated by the client, both the SpdySession and client object (such as
 // a SpdyNetworkTransaction) will maintain a reference to the stream.  When
 // initiated by the server, only the SpdySession will maintain any reference,
 // until such a time as a client object requests a stream for the path.
 class NET_EXPORT_PRIVATE SpdyStream {
@@ skipping 61 matching lines @@
     // EOF.  Must return OK if the data was received successfully, or
     // a network error code otherwise.
     //
     // May cause the stream to be closed.
     virtual void OnDataReceived(scoped_ptr<SpdyBuffer> buffer) = 0;
 
     // Called when data is sent. Must not cause the stream to be
     // closed.
     virtual void OnDataSent() = 0;
 
+    // Called when trailers are received. Note that trailers HEADER frame will
+    // have END_STREAM flag set, so this will be followed by OnClose.
+    virtual void OnTrailers(const SpdyHeaderBlock& trailers);

[Ryan Hamilton, 2015/08/10 17:23:25]

Is it required by the spec that trailers have the END_STREAM flag set, or is
this convention? Looks like section 8.1 of the HTTP/2 RFC requires END_STREAM be
set?

[Ryan Hamilton, 2015/08/10 17:23:25]

I think this should be = 0 (pure virtual), shouldn't it?

[xunjieli, 2015/08/10 20:31:07]

Done. I was not sure if all implementations should care about trailers.

[xunjieli, 2015/08/10 20:31:07]

The RFC says "The HEADERS frame starting the trailers header block has the
END_STREAM flag set." I think it is required that trailers header block has
END_STREAM flag. I edited the comment to make it clearer.

+
     // Called when SpdyStream is closed. No other delegate functions
     // will be called after this is called, and the delegate must not
     // access the stream after this is called. Must not cause the
     // stream to be be (re-)closed.
     //
     // TODO(akalin): Allow this function to re-close the stream and
     // handle it gracefully.
     virtual void OnClose(int status) = 0;
 
    protected:
@@ skipping 422 matching lines @@
   bool write_handler_guard_;
 
   base::WeakPtrFactory<SpdyStream> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SpdyStream);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_STREAM_H_