Ton

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/*
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    This file is part of TON Blockchain Library.
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    TON Blockchain Library is free software: you can redistribute it and/or modify
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    it under the terms of the GNU Lesser General Public License as published by
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    the Free Software Foundation, either version 2 of the License, or
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    (at your option) any later version.
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    TON Blockchain Library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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    GNU Lesser General Public License for more details.
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    You should have received a copy of the GNU Lesser General Public License
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    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
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    Copyright 2017-2020 Telegram Systems LLP
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*/
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#include "StreamToFileActor.h"
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namespace td {
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StreamToFileActor::StreamToFileActor(StreamReader reader, FileFd fd, FileSyncState::Writer sync_state, Options options)
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    : reader_(std::move(reader)), fd_(std::move(fd)), sync_state_(std::move(sync_state)) {
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}
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void StreamToFileActor::set_callback(td::unique_ptr<Callback> callback) {
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  callback_ = std::move(callback);
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  callback_->on_sync_state_changed();
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}
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Result<bool> StreamToFileActor::is_closed() {
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  if (!reader_.is_writer_closed()) {
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    return false;
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  }
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  return reader_.writer_status().clone();
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}
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Status StreamToFileActor::do_flush_once() {
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  auto size = reader_.reader_size();
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  size_t total_written = 0;
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  while (total_written < size) {
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    auto io_slices = reader_.prepare_readv();
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    TRY_RESULT(written, fd_.writev(io_slices));
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    reader_.confirm_read(written);
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    flushed_size_ += written;
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    total_written += written;
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  }
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  return Status::OK();
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}
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Status StreamToFileActor::do_sync() {
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  if (flushed_size_ == synced_size_) {
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    return Status::OK();
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  }
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  TRY_STATUS(fd_.sync());
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  synced_size_ = flushed_size_;
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  return Status::OK();
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}
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void StreamToFileActor::schedule_sync() {
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  if (synced_size_ == flushed_size_) {
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    return;
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  }
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  if (sync_state_.get_requested_synced_size() > synced_size_) {
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    sync_at_.relax(Timestamp::in(options_.immediate_sync_delay));
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  } else {
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    sync_at_.relax(Timestamp::in(options_.lazy_sync_delay));
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  }
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}
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Result<bool> StreamToFileActor::do_loop() {
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  // We must first check if writer is closed and then drain all data from reader
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  // Otherwise there will be a race and some of data could be lost.
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  // Also it could be useful to check error and stop immediately.
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  TRY_RESULT(is_closed, is_closed());
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  // Flush all data that is awailable on the at the beginning of loop
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  TRY_STATUS(do_flush_once());
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  if ((sync_at_ && sync_at_.is_in_past()) || is_closed) {
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    TRY_STATUS(do_sync());
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    sync_at_ = {};
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  }
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  bool need_update = sync_state_.set_synced_size(synced_size_) | sync_state_.set_flushed_size(flushed_size_);
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  if (need_update && callback_) {
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    callback_->on_sync_state_changed();
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  }
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  if (reader_.reader_size() == 0 && is_closed) {
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    return true;
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  }
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  schedule_sync();
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  return false;
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}
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void StreamToFileActor::start_up() {
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  schedule_sync();
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}
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void StreamToFileActor::loop() {
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  auto r_is_closed = do_loop();
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  if (r_is_closed.is_error()) {
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    reader_.close_reader(r_is_closed.move_as_error());
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    return stop();
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  } else if (r_is_closed.ok()) {
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    reader_.close_reader(Status::OK());
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    return stop();
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  }
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  alarm_timestamp() = sync_at_;
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}
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}  // namespace td
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