initial commit

tddb/td/db/utils/FileToStreamActor.cpp

@@ -0,0 +1,78 @@
+/*
+    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 "FileToStreamActor.h"
+
+namespace td {
+FileToStreamActor::FileToStreamActor(FileFd fd, StreamWriter writer, Options options)
+    : fd_(std::move(fd)), writer_(std::move(writer)), options_(options) {
+}
+
+void FileToStreamActor::set_callback(td::unique_ptr<Callback> callback) {
+  callback_ = std::move(callback);
+  got_more();
+}
+
+void FileToStreamActor::got_more() {
+  if (!callback_) {
+    return;
+  }
+  callback_->got_more();
+}
+void FileToStreamActor::loop() {
+  auto dest = writer_.prepare_write();
+  if (options_.limit != -1) {
+    if (static_cast<int64>(dest.size()) > options_.limit) {
+      dest.truncate(narrow_cast<size_t>(options_.limit));
+    }
+  }
+  if (dest.empty()) {
+    //NB: Owner of CyclicBufer::Reader should notify this actor after each chunk is readed
+    return;
+  }
+
+  auto r_size = fd_.read(dest);
+  if (r_size.is_error()) {
+    writer_.close_writer(r_size.move_as_error());
+    got_more();
+    return stop();
+  }
+  auto size = r_size.move_as_ok();
+  writer_.confirm_write(size);
+  got_more();
+  if (options_.limit != -1) {
+    options_.limit -= narrow_cast<int64>(size);
+  }
+  if (options_.limit == 0) {
+    writer_.close_writer(td::Status::OK());
+    got_more();
+    return stop();
+  }
+  if (size == 0) {
+    if (options_.read_tail_each < 0) {
+      writer_.close_writer(td::Status::OK());
+      got_more();
+      return stop();
+    }
+    alarm_timestamp() = Timestamp::in(options_.read_tail_each);
+    return;
+  }
+  yield();
+}
+
+}  // namespace td