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 "ChainBuffer.h"
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#include "td/utils/buffer.h"
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#include "td/db/utils/StreamInterface.h"
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namespace td {
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namespace detail {
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class ChainBuffer : public StreamWriterInterface, public StreamReaderInterface {
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 public:
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  using Options = ::td::ChainBuffer::Options;
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  ChainBuffer(Options options) {
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    shared_.options_ = options;
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    reader_.io_slices_.reserve(options.max_io_slices);
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    reader_.buf_ = writer_.buf_.extract_reader();
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  }
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  // StreamReaderInterface
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  size_t reader_size() override {
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    reader_.buf_.sync_with_writer();
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    return reader_.buf_.size();
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  }
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  Slice prepare_read() override {
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    return reader_.buf_.prepare_read();
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  }
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  Span<IoSlice> prepare_readv() override {
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    reader_.io_slices_.clear();
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    auto it = reader_.buf_.clone();
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    while (!it.empty() && reader_.io_slices_.size() < reader_.io_slices_.capacity()) {
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      auto slice = it.prepare_read();
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      reader_.io_slices_.push_back(as_io_slice(slice));
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      it.confirm_read(slice.size());
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    }
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    return reader_.io_slices_;
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  }
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  void confirm_read(size_t size) override {
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    reader_.buf_.advance(size);
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  }
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  void close_reader(Status error) override {
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    CHECK(!reader_.is_closed_);
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    reader_.status_ = std::move(error);
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    reader_.is_closed_.store(true, std::memory_order_release);
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  }
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  bool is_writer_closed() const override {
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    return writer_.is_closed_.load(std::memory_order_acquire);
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  }
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  Status &writer_status() override {
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    CHECK(is_writer_closed());
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    return writer_.status_;
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  }
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  // StreamWriterInterface
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  size_t writer_size() override {
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    return writer_.size_;
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  }
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  MutableSlice prepare_write() override {
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    return writer_.buf_.prepare_append(shared_.options_.chunk_size);
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  }
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  MutableSlice prepare_write_at_least(size_t size) override {
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    return writer_.buf_.prepare_append_at_least(size);
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  }
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  void confirm_write(size_t size) override {
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    writer_.buf_.confirm_append(size);
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    writer_.size_ += size;
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  }
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  void append(Slice data) override {
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    writer_.buf_.append(data, shared_.options_.chunk_size);
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    writer_.size_ += data.size();
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  }
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  void append(BufferSlice data) override {
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    writer_.size_ += data.size();
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    writer_.buf_.append(std::move(data));
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  }
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  void append(std::string data) override {
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    append(Slice(data));
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  }
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  void close_writer(Status error) override {
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    CHECK(!writer_.is_closed_);
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    writer_.status_ = std::move(error);
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    writer_.is_closed_.store(true, std::memory_order_release);
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  }
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  bool is_reader_closed() const override {
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    return reader_.is_closed_.load(std::memory_order_acquire);
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  }
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  Status &reader_status() override {
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    CHECK(is_reader_closed());
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    return reader_.status_;
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  }
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 private:
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  struct SharedData {
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    Options options_;
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  } shared_;
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  char pad1[128];
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  struct ReaderData {
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    ChainBufferReader buf_;
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    std::atomic<bool> is_closed_{false};
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    Status status_;
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    std::vector<IoSlice> io_slices_;
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  } reader_;
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  char pad2[128];
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  struct WriterData {
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    ChainBufferWriter buf_;
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    std::atomic<bool> is_closed_{false};
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    Status status_;
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    size_t size_{0};
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  } writer_;
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};
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}  // namespace detail
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std::pair<ChainBuffer::Reader, ChainBuffer::Writer> ChainBuffer::create(Options options) {
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  auto impl = std::make_shared<detail::ChainBuffer>(options);
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  return {Reader(impl), Writer(impl)};
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}
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}  // namespace td
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