CommitLog.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_CommitLog_h
#define Hypertable_Lib_CommitLog_h

#include <Hypertable/Lib/BlockCompressionCodec.h>
#include <Hypertable/Lib/CommitLogBase.h>
#include <Hypertable/Lib/CommitLogBlockStream.h>

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

#include <deque>
#include <map>
#include <memory>
#include <stack>

namespace Hypertable {


  class CommitLog : public CommitLogBase {

  public:

    struct CumulativeFragmentData {
      uint32_t distance;
      int64_t  size;
      int64_t  cumulative_size;
      uint32_t fragno;
    };

    typedef std::map<int64_t, CumulativeFragmentData> CumulativeSizeMap;

    CommitLog(FilesystemPtr &fs, const std::string &log_dir,
              PropertiesPtr &props, CommitLogBase *init_log = 0,
              bool is_meta=true)
      : CommitLogBase(log_dir), m_fs(fs) {
      initialize(log_dir, props, init_log, is_meta);
    }

    CommitLog(FilesystemPtr &fs, const std::string &log_dir, bool is_meta=true);

    virtual ~CommitLog();

    int64_t get_timestamp();

    int write(uint64_t cluster_id, DynamicBuffer &buffer, int64_t revision, Filesystem::Flags flags);

    int flush();

    int sync();

    int link_log(uint64_t cluster_id, CommitLogBase *log_base);

    int close();

    int purge(int64_t revision, StringSet &remove_ok_logs,
              StringSet &removed_logs, std::string *trace);

    void load_cumulative_size_map(CumulativeSizeMap &cumulative_size_map);

    int64_t get_max_fragment_size() { return m_max_fragment_size; }

    void get_stats(const std::string &prefix, std::string &result);

    int64_t size() {
      std::lock_guard<std::mutex>lock(m_mutex);
      int64_t total = 0;
      for (LogFragmentQueue::iterator iter = m_fragment_queue.begin();
           iter != m_fragment_queue.end(); iter++)
        total += (*iter)->size;
      return total;
    }

    const std::string& get_current_fragment_file() {
      std::lock_guard<std::mutex>lock(m_mutex);
      return m_cur_fragment_fname;
    }

    static const char MAGIC_DATA[10];
    static const char MAGIC_LINK[10];

  private:
    void initialize(const std::string &log_dir,
                    PropertiesPtr &, CommitLogBase *init_log, bool is_meta);
    int roll(CommitLogFileInfo **clfip=0);
    int compress_and_write(DynamicBuffer &input, BlockHeader *header,
                           int64_t revision, Filesystem::Flags flags);
    void remove_file_info(CommitLogFileInfo *fi, StringSet &removed_logs);

    FilesystemPtr           m_fs;
    std::set<CommitLogFileInfo *> m_reap_set;
    std::unique_ptr<BlockCompressionCodec> m_compressor;
    std::string                  m_cur_fragment_fname;
    int64_t                 m_cur_fragment_length;
    int64_t                 m_max_fragment_size;
    uint32_t                m_cur_fragment_num;
    int32_t                 m_fd;
    int32_t                 m_replication;
    bool                    m_needs_roll;
  };

  typedef std::shared_ptr<CommitLog> CommitLogPtr;


}

#endif // Hypertable_Lib_CommitLog_h