CommitLogBlockStream.h

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/* -*- c++ -*-
 * Copyright (C) 2007-2015 Hypertable, Inc.
 *
 * This file is part of Hypertable.
 *
 * Hypertable 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; version 3 of the
 * License, or any later version.
 *
 * Hypertable 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */


#ifndef Hypertable_Lib_CommitLogBlockStream_h
#define Hypertable_Lib_CommitLogBlockStream_h

#include <Hypertable/Lib/BlockHeaderCommitLog.h>

#include <Common/DynamicBuffer.h>
#include <Common/String.h>
#include <Common/Filesystem.h>
#include <Common/Status.h>

namespace Hypertable {


  struct CommitLogBlockInfo {
    const char *log_dir;
    const char *file_fragment;
    uint8_t *block_ptr;
    size_t block_len;
    uint64_t start_offset;
    uint64_t end_offset;
    int error;
  };


  class CommitLogBlockStream {

  public:

    CommitLogBlockStream(FilesystemPtr &fs);
    CommitLogBlockStream(FilesystemPtr &fs, const std::string &log_dir,
                         const std::string &fragment);
    virtual ~CommitLogBlockStream();

    void load(const std::string &log_dir, const std::string &fragment);
    void close();
    bool next(CommitLogBlockInfo *, BlockHeaderCommitLog *);

    std::string &get_fname() { return m_fname; }

    static bool ms_assert_on_error;

    static bool read_header(FilesystemPtr &fs, int32_t fd,
                            uint32_t *versionp, uint64_t *next_offset);

    static void write_header(FilesystemPtr &fs, int32_t fd);

    static uint64_t header_size();

  private:

    int load_next_valid_header(BlockHeaderCommitLog *header);

    bool archive_bad_fragment(const std::string &fname,
                              std::string &archive_fname);

    FilesystemPtr m_fs;

    std::string m_log_dir;

    std::string m_fragment;

    std::string m_fname;

    uint32_t m_version;

    int32_t m_fd;

    uint64_t m_cur_offset;

    uint64_t m_file_length;

    DynamicBuffer m_block_buffer;
  };

}

#endif // Hypertable_Lib_CommitLogBlockStream_h