initial commit

tddb/td/db/utils/StreamToFileActor.cpp

@@ -0,0 +1,112 @@
+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#include "StreamToFileActor.h"
+
+namespace td {
+StreamToFileActor::StreamToFileActor(StreamReader reader, FileFd fd, FileSyncState::Writer sync_state, Options options)
+    : reader_(std::move(reader)), fd_(std::move(fd)), sync_state_(std::move(sync_state)) {
+}
+void StreamToFileActor::set_callback(td::unique_ptr<Callback> callback) {
+  callback_ = std::move(callback);
+  callback_->on_sync_state_changed();
+}
+
+Result<bool> StreamToFileActor::is_closed() {
+  if (!reader_.is_writer_closed()) {
+    return false;
+  }
+  return reader_.writer_status().clone();
+}
+
+Status StreamToFileActor::do_flush_once() {
+  auto size = reader_.reader_size();
+  size_t total_written = 0;
+  while (total_written < size) {
+    auto io_slices = reader_.prepare_readv();
+    TRY_RESULT(written, fd_.writev(io_slices));
+    reader_.confirm_read(written);
+    flushed_size_ += written;
+    total_written += written;
+  }
+  return Status::OK();
+}
+
+Status StreamToFileActor::do_sync() {
+  if (flushed_size_ == synced_size_) {
+    return Status::OK();
+  }
+  TRY_STATUS(fd_.sync());
+  synced_size_ = flushed_size_;
+  return Status::OK();
+}
+
+void StreamToFileActor::schedule_sync() {
+  if (synced_size_ == flushed_size_) {
+    return;
+  }
+  if (sync_state_.get_requested_synced_size() > synced_size_) {
+    sync_at_.relax(Timestamp::in(options_.immediate_sync_delay));
+  } else {
+    sync_at_.relax(Timestamp::in(options_.lazy_sync_delay));
+  }
+}
+
+Result<bool> StreamToFileActor::do_loop() {
+  // We must first check if writer is closed and then drain all data from reader
+  // Otherwise there will be a race and some of data could be lost.
+  // Also it could be useful to check error and stop immediately.
+  TRY_RESULT(is_closed, is_closed());
+
+  // Flush all data that is awailable on the at the beginning of loop
+  TRY_STATUS(do_flush_once());
+
+  if ((sync_at_ && sync_at_.is_in_past()) || is_closed) {
+    TRY_STATUS(do_sync());
+    sync_at_ = {};
+  }
+
+  bool need_update = sync_state_.set_synced_size(synced_size_) | sync_state_.set_flushed_size(flushed_size_);
+  if (need_update && callback_) {
+    callback_->on_sync_state_changed();
+  }
+
+  if (reader_.reader_size() == 0 && is_closed) {
+    return true;
+  }
+
+  schedule_sync();
+  return false;
+}
+
+void StreamToFileActor::start_up() {
+  schedule_sync();
+}
+
+void StreamToFileActor::loop() {
+  auto r_is_closed = do_loop();
+  if (r_is_closed.is_error()) {
+    reader_.close_reader(r_is_closed.move_as_error());
+    return stop();
+  } else if (r_is_closed.ok()) {
+    reader_.close_reader(Status::OK());
+    return stop();
+  }
+  alarm_timestamp() = sync_at_;
+}
+}  // namespace td