YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#ifndef YB_RPC_REFINED_STREAM_H

#define YB_RPC_REFINED_STREAM_H

#include "yb/rpc/circular_read_buffer.h"

#include "yb/rpc/stream.h"

#include "yb/util/mem_tracker.h"

namespace yb {

namespace rpc {

YB_DEFINE_ENUM(RefinedStreamState, (kInitial)(kHandshake)(kEnabled)(kDisabled));

YB_DEFINE_ENUM(LocalSide, (kClient)(kServer));

// StreamRefiner is used by RefinedStream to perform actual stream data modification.

class StreamRefiner {

 public:

  virtual void Start(RefinedStream* stream) = 0;

  virtual CHECKED_STATUS ProcessHeader() = 0;

  virtual CHECKED_STATUS Send(OutboundDataPtr data) = 0;

  virtual CHECKED_STATUS Handshake() = 0;

  virtual Result<ReadBufferFull> Read(StreamReadBuffer* out) = 0;

  virtual const Protocol* GetProtocol() = 0;

  virtual std::string ToString() const = 0;

  virtual ~StreamRefiner() = default;

};

// Stream that alters the data sent and received by lower layer streams.

// For instance it could be used to compress or encrypt the data.

//

// RefinedStream keeps the code common to all such streams,

// while StreamRefiner provides actual data modification.

class RefinedStream : public Stream, public StreamContext {

 public:

  RefinedStream(std::unique_ptr<Stream> lower_stream, std::unique_ptr<StreamRefiner> refiner,

                size_t receive_buffer_size, const MemTrackerPtr& buffer_tracker);

  size_t GetPendingWriteBytes() override;

  void Close() override;

  CHECKED_STATUS TryWrite() override;

  void ParseReceived() override;

  bool Idle(std::string* reason) override;

  void DumpPB(const DumpRunningRpcsRequestPB& req, RpcConnectionPB* resp) override;

  const Endpoint& Remote() const override;

  const Endpoint& Local() const override;

  CHECKED_STATUS Start(bool connect, ev::loop_ref* loop, StreamContext* context) override;

  void Shutdown(const Status& status) override;

  Result<size_t> Send(OutboundDataPtr data) override;

  void Cancelled(size_t handle) override;

  bool IsConnected() override;

  const Protocol* GetProtocol() override;

  StreamReadBuffer& ReadBuffer() override;

  std::string ToString() const override;

  // Implementation StreamContext

  Result<size_t> ProcessReceived(ReadBufferFull read_buffer_full) override;

  void Connected() override;

  void UpdateLastActivity() override;

  void UpdateLastRead() override;

  void UpdateLastWrite() override;

  void Transferred(const OutboundDataPtr& data, const Status& status) override;

  void Destroy(const Status& status) override;

  CHECKED_STATUS Established(RefinedStreamState state);

  CHECKED_STATUS SendToLower(OutboundDataPtr data);

  CHECKED_STATUS StartHandshake();

  StreamContext& context() const {

    return *context_;

  }

  LocalSide local_side() const {

    return local_side_;

  }

  const MemTrackerPtr& buffer_tracker() const {

    return buffer_tracker_;

  }

 private:

  Result<size_t> Handshake();

  Result<size_t> Read();

  std::unique_ptr<Stream> lower_stream_;

  std::unique_ptr<StreamRefiner> refiner_;

  RefinedStreamState state_ = RefinedStreamState::kInitial;

  StreamContext* context_ = nullptr;

  std::vector<OutboundDataPtr> pending_data_;

  size_t upper_stream_bytes_to_skip_ = 0;

  LocalSide local_side_ = LocalSide::kServer;

  CircularReadBuffer read_buffer_;

  MemTrackerPtr buffer_tracker_;

};

class RefinedStreamFactory : public StreamFactory {

 public:

  using RefinerFactory = std::function<std::unique_ptr<StreamRefiner>(

        const StreamCreateData& data)>;

  RefinedStreamFactory(

      StreamFactoryPtr lower_layer_factory, const MemTrackerPtr& buffer_tracker,

      RefinerFactory refiner_factory);

 private:

  std::unique_ptr<Stream> Create(const StreamCreateData& data) override;

  StreamFactoryPtr lower_layer_factory_;

  MemTrackerPtr buffer_tracker_;

  RefinerFactory refiner_factory_;

};

}  // namespace rpc

}  // namespace yb

#endif  // YB_RPC_REFINED_STREAM_H