// Copyright (c) 2018 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 "quiche/quic/core/qpack/qpack_decoder_stream_sender.h"

#include <cstddef>
#include <limits>
#include <string>
#include <utility>

#include "absl/strings/string_view.h"
#include "quiche/quic/core/qpack/qpack_instructions.h"
#include "quiche/quic/platform/api/quic_flag_utils.h"
#include "quiche/quic/platform/api/quic_logging.h"

namespace quic {

QpackDecoderStreamSender::QpackDecoderStreamSender()
    : delegate_(nullptr),
      // None of the instructions sent by the QpackDecoderStreamSender
      // are strings, so huffman encoding is not relevant.
      instruction_encoder_(HuffmanEncoding::kEnabled) {}

void QpackDecoderStreamSender::SendInsertCountIncrement(uint64_t increment) {
  instruction_encoder_.Encode(
      QpackInstructionWithValues::InsertCountIncrement(increment), &buffer_);
}

void QpackDecoderStreamSender::SendHeaderAcknowledgement(
    QuicStreamId stream_id) {
  instruction_encoder_.Encode(
      QpackInstructionWithValues::HeaderAcknowledgement(stream_id), &buffer_);
}

void QpackDecoderStreamSender::SendStreamCancellation(QuicStreamId stream_id) {
  instruction_encoder_.Encode(
      QpackInstructionWithValues::StreamCancellation(stream_id), &buffer_);
}

void QpackDecoderStreamSender::Flush() {
  if (buffer_.empty() || delegate_ == nullptr) {
    return;
  }
  if (GetQuicRestartFlag(quic_opport_bundle_qpack_decoder_data5)) {
    QUIC_RESTART_FLAG_COUNT_N(quic_opport_bundle_qpack_decoder_data5, 3, 4);
    // Swap buffer_ before calling WriteStreamData, which might result in a
    // reentrant call to `Flush()`.
    std::string copy;
    std::swap(copy, buffer_);
    delegate_->WriteStreamData(copy);
    return;
  }
  delegate_->WriteStreamData(buffer_);
  buffer_.clear();
}

}  // namespace quic