QUIC - bugfix for forced head of line blocking experiment. Guarded by ENABLED --FLAGS_quic_bugfix_f…

net/quic/core/quic_headers_stream_test.cc

 // Copyright 2013 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.
 
 #include "net/quic/core/quic_headers_stream.h"
 
 #include <string>
 
 #include "base/strings/string_number_conversions.h"
 #include "net/quic/core/quic_bug_tracker.h"
@@ skipping 242 matching lines @@
     const iovec* iov = data.iov;
     int count = data.iov_count;
     int consumed = 0;
     for (int i = 0; i < count; ++i) {
       saved_data_.append(static_cast<char*>(iov[i].iov_base), iov[i].iov_len);
       consumed += iov[i].iov_len;
     }
     return QuicConsumedData(consumed, false);
   }
 
+  QuicConsumedData SaveIovShort(const QuicIOVector& data) {
+    const iovec* iov = data.iov;
+    int consumed = 1;
+    saved_data_.append(static_cast<char*>(iov[0].iov_base), consumed);
+    return QuicConsumedData(consumed, false);
+  }
+
   QuicConsumedData SaveIovAndNotifyAckListener(
       const QuicIOVector& data,
       QuicAckListenerInterface* ack_listener) {
     QuicConsumedData result = SaveIov(data);
     if (ack_listener) {
       ack_listener->OnPacketAcked(result.bytes_consumed,
                                   QuicTime::Delta::Zero());
     }
     return result;
   }
@@ skipping 713 matching lines @@
         // Notice, acked bytes doesn't include extra bytes used by
         // HTTP/2 DATA frame headers.
         EXPECT_EQ(ack_listener->total_acked_bytes(), data_len);
       }
       saved_data_.clear();
       saved_payloads_.clear();
     }
   }
 }
 
+TEST_P(QuicHeadersStreamTest, WritevStreamDataFinOnly) {
+  FLAGS_quic_bugfix_fhol_writev_fin_only_v2 = true;
+  struct iovec iov;
+  string data;
+
+  EXPECT_CALL(session_,
+              WritevData(headers_stream_, kHeadersStreamId, _, _, false, _))
+      .WillOnce(WithArgs<2, 5>(
+          Invoke(this, &QuicHeadersStreamTest::SaveIovAndNotifyAckListener)));
+
+  QuicConsumedData consumed_data = headers_stream_->WritevStreamData(
+      kClientDataStreamId1, MakeIOVector(data, &iov), 0, true, nullptr);
+
+  EXPECT_EQ(consumed_data.bytes_consumed, 0u);
+  EXPECT_EQ(consumed_data.fin_consumed, true);
+}
+
+TEST_P(QuicHeadersStreamTest, WritevStreamDataSendBlocked) {
+  FLAGS_quic_bugfix_fhol_writev_fin_only_v2 = true;
+  QuicStreamId id = kClientDataStreamId1;
+  QuicStreamOffset offset = 0;
+  struct iovec iov;
+  string data;
+
+  // This test will issue a write that will require fragmenting into
+  // multiple HTTP/2 DATA frames.  It will ensure that only 1 frame
+  // will go out in the case that the underlying session becomes write
+  // blocked.  Buffering is required to preserve framing, but the
+  // amount of buffering is limited to one HTTP/2 data frame.
+  const int kMinDataFrames = 4;
+  const size_t data_len = kSpdyInitialFrameSizeLimit * kMinDataFrames + 1024;
+  // Set headers stream send window large enough for data written below.
+  headers_stream_->flow_controller()->UpdateSendWindowOffset(data_len * 2 * 4);
+  test::GenerateBody(&data, data_len);
+
+  bool fin = true;
+  // So force the underlying |WritevData| to consume only 1 byte.
+  // In that case, |WritevStreamData| should consume just one
+  // HTTP/2 data frame's worth of data.
+  EXPECT_CALL(session_,
+              WritevData(headers_stream_, kHeadersStreamId, _, _, false, _))
+      .WillOnce(
+          WithArgs<2>(Invoke(this, &QuicHeadersStreamTest::SaveIovShort)));
+
+  QuicConsumedData consumed_data = headers_stream_->WritevStreamData(
+      id, MakeIOVector(data, &iov), offset, fin, nullptr);
+
+  // bytes_consumed is max HTTP/2 data frame size minus the HTTP/2
+  // data header size.
+  EXPECT_EQ(consumed_data.bytes_consumed,
+            kSpdyInitialFrameSizeLimit -
+                SpdyConstants::GetDataFrameMinimumSize(HTTP2));
+  EXPECT_EQ(consumed_data.fin_consumed, false);
+
+  // If session already blocked, then bytes_consumed should be zero.
+  consumed_data = headers_stream_->WritevStreamData(
+      id, MakeIOVector(data, &iov), offset, fin, nullptr);
+
+  EXPECT_EQ(consumed_data.bytes_consumed, 0u);
+  EXPECT_EQ(consumed_data.fin_consumed, false);
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace net