Track when QUIC connections are application limited. Protected by quic_enable_app_limited_check.

net/quic/core/quic_connection_test.cc

 // 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.
 
 #include "net/quic/core/quic_connection.h"
 
 #include <errno.h>
 #include <memory>
 #include <ostream>
 #include <utility>
@@ skipping 716 matching lines @@
         .WillRepeatedly(Return(QuicBandwidth::Zero()));
     ON_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
         .WillByDefault(Return(true));
     EXPECT_CALL(*send_algorithm_, HasReliableBandwidthEstimate())
         .Times(AnyNumber());
     EXPECT_CALL(*send_algorithm_, BandwidthEstimate())
         .Times(AnyNumber())
         .WillRepeatedly(Return(QuicBandwidth::Zero()));
     EXPECT_CALL(*send_algorithm_, InSlowStart()).Times(AnyNumber());
     EXPECT_CALL(*send_algorithm_, InRecovery()).Times(AnyNumber());
+    EXPECT_CALL(*send_algorithm_, OnApplicationLimited(_)).Times(AnyNumber());
     EXPECT_CALL(visitor_, WillingAndAbleToWrite()).Times(AnyNumber());
     EXPECT_CALL(visitor_, HasPendingHandshake()).Times(AnyNumber());
     EXPECT_CALL(visitor_, OnCanWrite()).Times(AnyNumber());
     EXPECT_CALL(visitor_, PostProcessAfterData()).Times(AnyNumber());
     EXPECT_CALL(visitor_, HasOpenDynamicStreams())
         .WillRepeatedly(Return(false));
     EXPECT_CALL(visitor_, OnCongestionWindowChange(_)).Times(AnyNumber());
 
     EXPECT_CALL(*loss_algorithm_, GetLossTimeout())
         .WillRepeatedly(Return(QuicTime::Zero()));
@@ skipping 1190 matching lines @@
   EXPECT_FALSE(ack_alarm->IsSet());
 }
 
 TEST_P(QuicConnectionTest, OnCanWrite) {
   // Visitor's OnCanWrite will send data, but will have more pending writes.
   EXPECT_CALL(visitor_, OnCanWrite())
       .WillOnce(DoAll(IgnoreResult(InvokeWithoutArgs(
                           &connection_, &TestConnection::SendStreamData3)),
                       IgnoreResult(InvokeWithoutArgs(
                           &connection_, &TestConnection::SendStreamData5))));
-  EXPECT_CALL(visitor_, WillingAndAbleToWrite()).WillOnce(Return(true));
+  {
+    InSequence seq;
+    EXPECT_CALL(visitor_, WillingAndAbleToWrite()).WillOnce(Return(true));
+    EXPECT_CALL(visitor_, WillingAndAbleToWrite())
+        .WillRepeatedly(Return(false));
+  }
+
   EXPECT_CALL(*send_algorithm_, TimeUntilSend(_, _))
       .WillRepeatedly(testing::Return(QuicTime::Delta::Zero()));
 
   connection_.OnCanWrite();
 
   // Parse the last packet and ensure it's the two stream frames from
   // two different streams.
   EXPECT_EQ(2u, writer_->frame_count());
   EXPECT_EQ(2u, writer_->stream_frames().size());
   EXPECT_EQ(kClientDataStreamId1, writer_->stream_frames()[0]->stream_id);
@@ skipping 3020 matching lines @@
   // close packet.
   FLAGS_quic_close_connection_on_packet_too_large = true;
   AlwaysGetPacketTooLarge();
   EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(2);
   EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_PACKET_WRITE_ERROR, _,
                                            ConnectionCloseSource::FROM_SELF))
       .Times(1);
   connection_.SendStreamDataWithString(3, "foo", 0, !kFin, nullptr);
 }
 
+// Verify that if connection has no outstanding data, it notifies the send
+// algorithm after the write.
+TEST_P(QuicConnectionTest, SendDataAndBecomeApplicationLimited) {
+  FLAGS_quic_enable_app_limited_check = true;
+
+  EXPECT_CALL(*send_algorithm_, OnApplicationLimited(_)).Times(1);
+  {
+    InSequence seq;
+    EXPECT_CALL(visitor_, WillingAndAbleToWrite()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
+        .WillOnce(Return(true));
+    EXPECT_CALL(visitor_, WillingAndAbleToWrite())
+        .WillRepeatedly(Return(false));
+  }
+
+  connection_.SendStreamData3();
+}
+
+// Verify that the connection does not become app-limited if there is
+// outstanding data to send after the write.
+TEST_P(QuicConnectionTest, NotBecomeApplicationLimitedIfMoreDataAvailable) {
+  FLAGS_quic_enable_app_limited_check = true;
+
+  EXPECT_CALL(*send_algorithm_, OnApplicationLimited(_)).Times(0);
+  {
+    InSequence seq;
+    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
+        .WillOnce(Return(true));
+    EXPECT_CALL(visitor_, WillingAndAbleToWrite()).WillRepeatedly(Return(true));
+  }
+
+  connection_.SendStreamData3();
+}
+
+// Verify that the connection does not become app-limited after blocked write
+// even if there is outstanding data to send after the write.
+TEST_P(QuicConnectionTest, NotBecomeApplicationLimitedDueToWriteBlock) {
+  FLAGS_quic_enable_app_limited_check = true;
+
+  EXPECT_CALL(*send_algorithm_, OnApplicationLimited(_)).Times(0);
+  EXPECT_CALL(visitor_, WillingAndAbleToWrite()).WillRepeatedly(Return(true));
+  BlockOnNextWrite();
+
+  connection_.SendStreamData3();
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace net