//  Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.

//  This source code is licensed under both the GPLv2 (found in the

//  COPYING file in the root directory) and Apache 2.0 License

//  (found in the LICENSE.Apache file in the root directory).

#pragma once

#include <array>

#include "file/sequence_file_reader.h"

namespace ROCKSDB_NAMESPACE {

// A wrapper on top of Env::SequentialFile for reading text lines from a file.

// Lines are delimited by '\n'. The last line may or may not include a

// trailing newline. Uses SequentialFileReader internally.

class LineFileReader {

 private:

  std::array<char, 8192> buf_;

  SequentialFileReader sfr_;

  IOStatus io_status_;

  const char* buf_begin_ = buf_.data();

  const char* buf_end_ = buf_.data();

  size_t line_number_ = 0;

  bool at_eof_ = false;

 public:

  // See SequentialFileReader constructors

  template <typename... Args>

  explicit LineFileReader(Args&&... args)

      : sfr_(std::forward<Args&&>(args)...) {}

rocksdb::LineFileReader::LineFileReader<std::__1::unique_ptr<rocksdb::FSSequentialFile, std::__1::default_delete<rocksdb::FSSequentialFile> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long&>(std::__1::unique_ptr<rocksdb::FSSequentialFile, std::__1::default_delete<rocksdb::FSSequentialFile> >&&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long&)

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      : sfr_(std::forward<Args&&>(args)...) {}

Unexecuted instantiation: rocksdb::LineFileReader::LineFileReader<std::__1::unique_ptr<rocksdb::FSSequentialFile, std::__1::default_delete<rocksdb::FSSequentialFile> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, decltype(nullptr), std::__1::vector<std::__1::shared_ptr<rocksdb::EventListener>, std::__1::allocator<std::__1::shared_ptr<rocksdb::EventListener> > >, rocksdb::RateLimiter*&>(std::__1::unique_ptr<rocksdb::FSSequentialFile, std::__1::default_delete<rocksdb::FSSequentialFile> >&&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, decltype(nullptr)&&, std::__1::vector<std::__1::shared_ptr<rocksdb::EventListener>, std::__1::allocator<std::__1::shared_ptr<rocksdb::EventListener> > >&&, rocksdb::RateLimiter*&)

  static IOStatus Create(const std::shared_ptr<FileSystem>& fs,

                         const std::string& fname, const FileOptions& file_opts,

                         std::unique_ptr<LineFileReader>* reader,

                         IODebugContext* dbg, RateLimiter* rate_limiter);

  LineFileReader(const LineFileReader&) = delete;

  LineFileReader& operator=(const LineFileReader&) = delete;

  // Reads another line from the file, returning true on success and saving

  // the line to `out`, without delimiter, or returning false on failure. You

  // must check GetStatus() to determine whether the failure was just

  // end-of-file (OK status) or an I/O error (another status).

  // The internal rate limiter will be charged at the specified priority.

  bool ReadLine(std::string* out, Env::IOPriority rate_limiter_priority);

  // Returns the number of the line most recently returned from ReadLine.

  // Return value is unspecified if ReadLine has returned false due to

  // I/O error. After ReadLine returns false due to end-of-file, return

  // value is the last returned line number, or equivalently the total

  // number of lines returned.

  size_t GetLineNumber() const { return line_number_; }

  // Returns any error encountered during read. The error is considered

  // permanent and no retry or recovery is attempted with the same

  // LineFileReader.

  const IOStatus& GetStatus() const { return io_status_; }

};

}  // namespace ROCKSDB_NAMESPACE