direct_io_file.hpp

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/*
 * Copyright (c) 2014-2015, Hewlett-Packard Development Company, LP.
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program 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 General Public License for
 * more details. You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * HP designates this particular file as subject to the "Classpath" exception
 * as provided by HP in the LICENSE.txt file that accompanied this code.
 */
#ifndef FOEDUS_FS_DIRECT_IO_FILE_HPP_
#define FOEDUS_FS_DIRECT_IO_FILE_HPP_
#include <stdint.h>

#include <iosfwd>
#include <string>

#include "foedus/cxx11.hpp"
#include "foedus/error_code.hpp"
#include "foedus/fs/device_emulation_options.hpp"
#include "foedus/fs/path.hpp"
#include "foedus/memory/fwd.hpp"

namespace foedus {
namespace fs {

class DirectIoFile {
 public:
  typedef int file_descriptor;
  enum Constants {
    kInvalidDescriptor = -1,
  };

  enum SeekType {
    kDirectIoSeekSet = 0,
    kDirectIoSeekCur,
    kDirectIoSeekEnd,
  };

  DirectIoFile(
    const Path &path,
    const DeviceEmulationOptions &emulation = DeviceEmulationOptions());

  ~DirectIoFile();

  // Disable default constructors
  DirectIoFile() CXX11_FUNC_DELETE;
  DirectIoFile(const DirectIoFile &) CXX11_FUNC_DELETE;
  DirectIoFile& operator=(const DirectIoFile &) CXX11_FUNC_DELETE;

  ErrorCode       open(bool read, bool write, bool append, bool create);

  bool            is_opened() const { return descriptor_ != kInvalidDescriptor; }

  bool            close();

  ErrorCode       read(uint64_t desired_bytes, foedus::memory::AlignedMemory* buffer);
  ErrorCode       read(uint64_t desired_bytes, const foedus::memory::AlignedMemorySlice& slice);
  ErrorCode       read_raw(uint64_t desired_bytes, void* buffer);

  ErrorCode       write(uint64_t desired_bytes, const foedus::memory::AlignedMemory& buffer);
  ErrorCode       write(uint64_t desired_bytes, const foedus::memory::AlignedMemorySlice& slice);
  ErrorCode       write_raw(uint64_t desired_bytes, const void* buffer);

  ErrorCode       truncate(uint64_t new_length, bool sync = false);

  ErrorCode       seek(uint64_t offset, SeekType seek_type);


  ErrorCode       sync();


  Path                    get_path() const { return path_; }
  DeviceEmulationOptions  get_emulation() const { return emulation_; }
  file_descriptor         get_descriptor() const { return descriptor_; }
  uint64_t                get_current_offset() const { return current_offset_; }
  bool                    is_read() const { return read_; }
  bool                    is_write() const { return write_; }

  std::string             to_string() const;
  friend std::ostream&    operator<<(std::ostream& o, const DirectIoFile& v);

 private:
  Path                    path_;

  DeviceEmulationOptions  emulation_;

  file_descriptor         descriptor_;

  bool                    read_;

  bool                    write_;

  uint64_t                current_offset_;
};
}  // namespace fs
}  // namespace foedus
#endif  // FOEDUS_FS_DIRECT_IO_FILE_HPP_