Coalesce small buffers in net::BidirectionalStream

net/quic/bidirectional_stream_quic_impl.cc

Index: net/quic/bidirectional_stream_quic_impl.cc
diff --git a/net/quic/bidirectional_stream_quic_impl.cc b/net/quic/bidirectional_stream_quic_impl.cc
index 6e560321a6cd16e1ed14677957b57f9582ef9aa1..95a945ee141197b4b358df788fc87cacaa8471e1 100644
--- a/net/quic/bidirectional_stream_quic_impl.cc
+++ b/net/quic/bidirectional_stream_quic_impl.cc
@@ -9,6 +9,7 @@
 #include "base/logging.h"
 #include "base/timer/timer.h"
 #include "net/http/bidirectional_stream_request_info.h"
+#include "net/quic/quic_connection.h"
 #include "net/socket/next_proto.h"
 #include "net/spdy/spdy_header_block.h"
 #include "net/spdy/spdy_http_utils.h"
@@ -31,6 +32,7 @@ BidirectionalStreamQuicImpl::BidirectionalStreamQuicImpl(
       closed_stream_sent_bytes_(0),
       has_sent_headers_(false),
       has_received_headers_(false),
+      disable_auto_flush_(false),
       weak_factory_(this) {
   DCHECK(session_);
   session_->AddObserver(this);
@@ -45,10 +47,12 @@ BidirectionalStreamQuicImpl::~BidirectionalStreamQuicImpl() {
 void BidirectionalStreamQuicImpl::Start(
     const BidirectionalStreamRequestInfo* request_info,
     const BoundNetLog& net_log,
+    bool disable_auto_flush,
     BidirectionalStreamImpl::Delegate* delegate,
     scoped_ptr<base::Timer> /* timer */) {
   DCHECK(!stream_);
 
+  disable_auto_flush_ = disable_auto_flush;
   if (!session_) {
     NotifyError(was_handshake_confirmed_ ? ERR_QUIC_PROTOCOL_ERROR
                                          : ERR_QUIC_HANDSHAKE_FAILED);
@@ -112,6 +116,38 @@ void BidirectionalStreamQuicImpl::SendData(IOBuffer* data,
   }
 }
 
+void BidirectionalStreamQuicImpl::SendvData(
+    const std::vector<IOBuffer*>& buffers,
+    const std::vector<int>& lengths,
+    bool end_stream) {
+  DCHECK(stream_);
+  DCHECK_EQ(buffers.size(), lengths.size());
+
+  QuicConnection::ScopedPacketBundler bundler(
+      session_->connection(), QuicConnection::SEND_ACK_IF_PENDING);
+  if (!has_sent_headers_) {
+    SendRequestHeaders();
+  }
+
+  std::vector<base::StringPiece> input_buffers;
+  for (size_t i = 0; i < buffers.size(); ++i) {
+    base::StringPiece string_data(buffers[i]->data(), lengths[i]);
+    input_buffers.push_back(string_data);

[Ryan Hamilton, 2016/04/13 03:42:28]

Instead of allocating a new std::vector with StringPiece copies of the IOBuffers
and then passing them to a newly created Writev method, how about simply calling
WritevStreamData for each chunk of data to be written?

[xunjieli, 2016/04/13 14:53:15]

Done. I got rid of the newly allocated std::vector. But I am not sure if that is
what you meant. Calling WriteStreamData on each chunk is not feasible right?
Because WriteStreamData has a DCHECK to make sure that it is called only when
there is no buffered data. If we get rid of Writev and use WriteStreamData, then
won't we encounter the DCHECK(!HasBufferedData()) ?

+  }
+
+  int rv = stream_->WritevStreamData(
+      input_buffers, end_stream,
+      base::Bind(&BidirectionalStreamQuicImpl::OnSendDataComplete,
+                 weak_factory_.GetWeakPtr()));
+
+  DCHECK(rv == OK || rv == ERR_IO_PENDING);
+  if (rv == OK) {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&BidirectionalStreamQuicImpl::OnSendDataComplete,
+                              weak_factory_.GetWeakPtr(), OK));
+  }
+}
+
 void BidirectionalStreamQuicImpl::Cancel() {
   if (stream_) {
     stream_->SetDelegate(nullptr);
@@ -208,7 +244,10 @@ void BidirectionalStreamQuicImpl::OnStreamReady(int rv) {
   DCHECK(rv == OK || !stream_);
   if (rv == OK) {
     stream_->SetDelegate(this);
-    SendRequestHeaders();
+    if (!disable_auto_flush_) {
+      SendRequestHeaders();
+    }
+    delegate_->OnStreamReady();
   } else {
     NotifyError(rv);
   }
@@ -240,7 +279,6 @@ void BidirectionalStreamQuicImpl::SendRequestHeaders() {
       headers, request_info_->end_stream_on_headers, nullptr);
   headers_bytes_sent_ += frame_len;
   has_sent_headers_ = true;
-  delegate_->OnHeadersSent();
 }
 
 void BidirectionalStreamQuicImpl::NotifyError(int error) {