// 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/quic_stream_sequencer.h"

#include <utility>
#include <vector>

#include "base/logging.h"
#include "base/rand_util.h"
#include "net/base/ip_endpoint.h"
#include "net/quic/quic_utils.h"
#include "net/quic/reliable_quic_stream.h"
#include "net/quic/test_tools/quic_stream_sequencer_peer.h"
#include "net/quic/test_tools/quic_test_utils.h"
#include "net/test/gtest_util.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

using base::StringPiece;
using std::map;
using std::min;
using std::pair;
using std::vector;
using testing::_;
using testing::AnyNumber;
using testing::InSequence;
using testing::Return;
using testing::StrEq;

namespace net {
namespace test {

class MockStream : public ReliableQuicStream {
 public:
  MockStream(QuicSession* session, QuicStreamId id)
      : ReliableQuicStream(id, session) {
  }

  MOCK_METHOD0(OnFinRead, void());
  MOCK_METHOD2(ProcessRawData, uint32(const char* data, uint32 data_len));
  MOCK_METHOD2(CloseConnectionWithDetails, void(QuicErrorCode error,
                                                const string& details));
  MOCK_METHOD1(Reset, void(QuicRstStreamErrorCode error));
  MOCK_METHOD0(OnCanWrite, void());
  virtual QuicPriority EffectivePriority() const OVERRIDE {
    return QuicUtils::HighestPriority();
  }
  virtual bool IsFlowControlEnabled() const {
    return true;
  }
};

namespace {

static const char kPayload[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

class QuicStreamSequencerTest : public ::testing::Test {
 protected:
  QuicStreamSequencerTest()
      : connection_(new MockConnection(false)),
        session_(connection_),
        stream_(&session_, 1),
        sequencer_(new QuicStreamSequencer(&stream_)),
        buffered_frames_(
            QuicStreamSequencerPeer::GetBufferedFrames(sequencer_.get())) {
  }

  bool VerifyReadableRegions(const char** expected, size_t num_expected) {
    iovec iovecs[5];
    size_t num_iovecs = sequencer_->GetReadableRegions(iovecs,
                                                       arraysize(iovecs));
    return VerifyIovecs(iovecs, num_iovecs, expected, num_expected);
  }

  bool VerifyIovecs(iovec* iovecs,
                    size_t num_iovecs,
                    const char** expected,
                    size_t num_expected) {
    if (num_expected != num_iovecs) {
      LOG(ERROR) << "Incorrect number of iovecs.  Expected: "
                 << num_expected << " Actual: " << num_iovecs;
      return false;
    }
    for (size_t i = 0; i < num_expected; ++i) {
      if (!VerifyIovec(iovecs[i], expected[i])) {
        return false;
      }
    }
    return true;
  }

  bool VerifyIovec(const iovec& iovec, StringPiece expected) {
    if (iovec.iov_len != expected.length()) {
      LOG(ERROR) << "Invalid length: " << iovec.iov_len
                 << " vs " << expected.length();
      return false;
    }
    if (memcmp(iovec.iov_base, expected.data(), expected.length()) != 0) {
      LOG(ERROR) << "Invalid data: " << static_cast<char*>(iovec.iov_base)
                 << " vs " << expected.data();
      return false;
    }
    return true;
  }

  bool OnFinFrame(QuicStreamOffset byte_offset, const char* data) {
    QuicStreamFrame frame;
    frame.stream_id = 1;
    frame.offset = byte_offset;
    frame.data.Append(const_cast<char*>(data), strlen(data));
    frame.fin = true;
    return sequencer_->OnStreamFrame(frame);
  }

  bool OnFrame(QuicStreamOffset byte_offset, const char* data) {
    QuicStreamFrame frame;
    frame.stream_id = 1;
    frame.offset = byte_offset;
    frame.data.Append(const_cast<char*>(data), strlen(data));
    frame.fin = false;
    return sequencer_->OnStreamFrame(frame);
  }

  MockConnection* connection_;
  MockSession session_;
  testing::StrictMock<MockStream> stream_;
  scoped_ptr<QuicStreamSequencer> sequencer_;
  map<QuicStreamOffset, string>* buffered_frames_;
};

TEST_F(QuicStreamSequencerTest, RejectOldFrame) {
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));

  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(0u, buffered_frames_->size());
  EXPECT_EQ(3u, sequencer_->num_bytes_consumed());
  // Ignore this - it matches a past sequence number and we should not see it
  // again.
  EXPECT_TRUE(OnFrame(0, "def"));
  EXPECT_EQ(0u, buffered_frames_->size());
}

TEST_F(QuicStreamSequencerTest, RejectBufferedFrame) {
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3));

  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
  // Ignore this - it matches a buffered frame.
  // Right now there's no checking that the payload is consistent.
  EXPECT_TRUE(OnFrame(0, "def"));
  EXPECT_EQ(1u, buffered_frames_->size());
}

TEST_F(QuicStreamSequencerTest, FullFrameConsumed) {
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));

  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(0u, buffered_frames_->size());
  EXPECT_EQ(3u, sequencer_->num_bytes_consumed());
}

TEST_F(QuicStreamSequencerTest, BlockedThenFullFrameConsumed) {
  sequencer_->SetBlockedUntilFlush();

  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());

  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));
  sequencer_->FlushBufferedFrames();
  EXPECT_EQ(0u, buffered_frames_->size());
  EXPECT_EQ(3u, sequencer_->num_bytes_consumed());

  EXPECT_CALL(stream_, ProcessRawData(StrEq("def"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, OnFinRead());
  EXPECT_TRUE(OnFinFrame(3, "def"));
}

TEST_F(QuicStreamSequencerTest, BlockedThenFullFrameAndFinConsumed) {
  sequencer_->SetBlockedUntilFlush();

  EXPECT_TRUE(OnFinFrame(0, "abc"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());

  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, OnFinRead());
  sequencer_->FlushBufferedFrames();
  EXPECT_EQ(0u, buffered_frames_->size());
  EXPECT_EQ(3u, sequencer_->num_bytes_consumed());
}

TEST_F(QuicStreamSequencerTest, EmptyFrame) {
  EXPECT_CALL(stream_,
              CloseConnectionWithDetails(QUIC_INVALID_STREAM_FRAME, _));
  EXPECT_FALSE(OnFrame(0, ""));
  EXPECT_EQ(0u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
}

TEST_F(QuicStreamSequencerTest, EmptyFinFrame) {
  EXPECT_CALL(stream_, OnFinRead());
  EXPECT_TRUE(OnFinFrame(0, ""));
  EXPECT_EQ(0u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
}

TEST_F(QuicStreamSequencerTest, PartialFrameConsumed) {
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(2));

  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(2u, sequencer_->num_bytes_consumed());
  EXPECT_EQ("c", buffered_frames_->find(2)->second);
}

TEST_F(QuicStreamSequencerTest, NextxFrameNotConsumed) {
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(0));

  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
  EXPECT_EQ("abc", buffered_frames_->find(0)->second);
}

TEST_F(QuicStreamSequencerTest, FutureFrameNotProcessed) {
  EXPECT_TRUE(OnFrame(3, "abc"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
  EXPECT_EQ("abc", buffered_frames_->find(3)->second);
}

TEST_F(QuicStreamSequencerTest, OutOfOrderFrameProcessed) {
  // Buffer the first
  EXPECT_TRUE(OnFrame(6, "ghi"));
  EXPECT_EQ(1u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
  EXPECT_EQ(3u, sequencer_->num_bytes_buffered());
  // Buffer the second
  EXPECT_TRUE(OnFrame(3, "def"));
  EXPECT_EQ(2u, buffered_frames_->size());
  EXPECT_EQ(0u, sequencer_->num_bytes_consumed());
  EXPECT_EQ(6u, sequencer_->num_bytes_buffered());

  InSequence s;
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, ProcessRawData(StrEq("def"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, ProcessRawData(StrEq("ghi"), 3)).WillOnce(Return(3));

  // Ack right away
  EXPECT_TRUE(OnFrame(0, "abc"));
  EXPECT_EQ(9u, sequencer_->num_bytes_consumed());
  EXPECT_EQ(0u, sequencer_->num_bytes_buffered());

  EXPECT_EQ(0u, buffered_frames_->size());
}

TEST_F(QuicStreamSequencerTest, BasicHalfCloseOrdered) {
  InSequence s;

  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, OnFinRead());
  EXPECT_TRUE(OnFinFrame(0, "abc"));

  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));
}

TEST_F(QuicStreamSequencerTest, BasicHalfCloseUnorderedWithFlush) {
  OnFinFrame(6, "");
  EXPECT_EQ(6u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));
  InSequence s;
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, ProcessRawData(StrEq("def"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, OnFinRead());

  EXPECT_TRUE(OnFrame(3, "def"));
  EXPECT_TRUE(OnFrame(0, "abc"));
}

TEST_F(QuicStreamSequencerTest, BasicHalfUnordered) {
  OnFinFrame(3, "");
  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));
  InSequence s;
  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(3));
  EXPECT_CALL(stream_, OnFinRead());

  EXPECT_TRUE(OnFrame(0, "abc"));
}

TEST_F(QuicStreamSequencerTest, TerminateWithReadv) {
  char buffer[3];

  OnFinFrame(3, "");
  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));

  EXPECT_FALSE(sequencer_->IsClosed());

  EXPECT_CALL(stream_, ProcessRawData(StrEq("abc"), 3)).WillOnce(Return(0));
  EXPECT_TRUE(OnFrame(0, "abc"));

  iovec iov = {&buffer[0], 3};
  int bytes_read = sequencer_->Readv(&iov, 1);
  EXPECT_EQ(3, bytes_read);
  EXPECT_TRUE(sequencer_->IsClosed());
}

TEST_F(QuicStreamSequencerTest, MutipleOffsets) {
  OnFinFrame(3, "");
  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));

  EXPECT_CALL(stream_, Reset(QUIC_MULTIPLE_TERMINATION_OFFSETS));
  OnFinFrame(5, "");
  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));

  EXPECT_CALL(stream_, Reset(QUIC_MULTIPLE_TERMINATION_OFFSETS));
  OnFinFrame(1, "");
  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));

  OnFinFrame(3, "");
  EXPECT_EQ(3u, QuicStreamSequencerPeer::GetCloseOffset(sequencer_.get()));
}

class QuicSequencerRandomTest : public QuicStreamSequencerTest {
 public:
  typedef pair<int, string> Frame;
  typedef vector<Frame> FrameList;

  void CreateFrames() {
    int payload_size = arraysize(kPayload) - 1;
    int remaining_payload = payload_size;
    while (remaining_payload != 0) {
      int size = min(OneToN(6), remaining_payload);
      int index = payload_size - remaining_payload;
      list_.push_back(make_pair(index, string(kPayload + index, size)));
      remaining_payload -= size;
    }
  }

  QuicSequencerRandomTest() {
    CreateFrames();
  }

  int OneToN(int n) {
    return base::RandInt(1, n);
  }

  int MaybeProcessMaybeBuffer(const char* data, uint32 len) {
    int to_process = len;
    if (base::RandUint64() % 2 != 0) {
      to_process = base::RandInt(0, len);
    }
    output_.append(data, to_process);
    return to_process;
  }

  string output_;
  FrameList list_;
};

// All frames are processed as soon as we have sequential data.
// Infinite buffering, so all frames are acked right away.
TEST_F(QuicSequencerRandomTest, RandomFramesNoDroppingNoBackup) {
  InSequence s;
  for (size_t i = 0; i < list_.size(); ++i) {
    string* data = &list_[i].second;
    EXPECT_CALL(stream_, ProcessRawData(StrEq(*data), data->size()))
        .WillOnce(Return(data->size()));
  }

  while (!list_.empty()) {
    int index = OneToN(list_.size()) - 1;
    LOG(ERROR) << "Sending index " << index << " " << list_[index].second;
    EXPECT_TRUE(OnFrame(list_[index].first, list_[index].second.data()));

    list_.erase(list_.begin() + index);
  }
}

TEST_F(QuicStreamSequencerTest, FrameOverlapsBufferedData) {
  // Ensure that FrameOverlapsBufferedData returns appropriate responses when
  // there is existing data buffered.

  map<QuicStreamOffset, string>* buffered_frames =
      QuicStreamSequencerPeer::GetBufferedFrames(sequencer_.get());

  const int kBufferedOffset = 10;
  const int kBufferedDataLength = 3;
  const int kNewDataLength = 3;
  IOVector data = MakeIOVector(string(kNewDataLength, '.'));

  // No overlap if no buffered frames.
  EXPECT_TRUE(buffered_frames_->empty());
  EXPECT_FALSE(sequencer_->FrameOverlapsBufferedData(
      QuicStreamFrame(1, false, kBufferedOffset - 1, data)));

  // Add a buffered frame.
  buffered_frames->insert(
      make_pair(kBufferedOffset, string(kBufferedDataLength, '.')));

  // New byte range partially overlaps with buffered frame, start offset
  // preceeding buffered frame.
  EXPECT_TRUE(sequencer_->FrameOverlapsBufferedData(
      QuicStreamFrame(1, false, kBufferedOffset - 1, data)));
  EXPECT_TRUE(sequencer_->FrameOverlapsBufferedData(
      QuicStreamFrame(1, false, kBufferedOffset - kNewDataLength + 1, data)));

  // New byte range partially overlaps with buffered frame, start offset
  // inside existing buffered frame.
  EXPECT_TRUE(sequencer_->FrameOverlapsBufferedData(
      QuicStreamFrame(1, false, kBufferedOffset + 1, data)));
  EXPECT_TRUE(sequencer_->FrameOverlapsBufferedData(QuicStreamFrame(
      1, false, kBufferedOffset + kBufferedDataLength - 1, data)));

  // New byte range entirely outside of buffered frames, start offset preceeding
  // buffered frame.
  EXPECT_FALSE(sequencer_->FrameOverlapsBufferedData(
      QuicStreamFrame(1, false, kBufferedOffset - kNewDataLength, data)));

  // New byte range entirely outside of buffered frames, start offset later than
  // buffered frame.
  EXPECT_FALSE(sequencer_->FrameOverlapsBufferedData(QuicStreamFrame(
      1, false, kBufferedOffset + kBufferedDataLength, data)));
}

TEST_F(QuicStreamSequencerTest, DontAcceptOverlappingFrames) {
  // The peer should never send us non-identical stream frames which contain
  // overlapping byte ranges - if they do, we close the connection.

  QuicStreamFrame frame1(kClientDataStreamId1, false, 1, MakeIOVector("hello"));
  sequencer_->OnStreamFrame(frame1);

  QuicStreamFrame frame2(kClientDataStreamId1, false, 2, MakeIOVector("hello"));
  EXPECT_TRUE(sequencer_->FrameOverlapsBufferedData(frame2));
  EXPECT_CALL(stream_, CloseConnectionWithDetails(QUIC_INVALID_STREAM_FRAME, _))
      .Times(1);
  sequencer_->OnStreamFrame(frame2);
}

}  // namespace
}  // namespace test
}  // namespace net