meta_log_buffer.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_LOG_META_LOG_BUFFER_HPP_
#define FOEDUS_LOG_META_LOG_BUFFER_HPP_
#include <stdint.h>

#include <iosfwd>

#include "foedus/attachable.hpp"
#include "foedus/epoch.hpp"
#include "foedus/error_stack.hpp"
#include "foedus/fwd.hpp"
#include "foedus/log/fwd.hpp"
#include "foedus/soc/shared_mutex.hpp"
#include "foedus/soc/shared_polling.hpp"

namespace foedus {
namespace log {

struct MetaLogControlBlock {
  void initialize() {
    mutex_.initialize();
    logger_wakeup_.initialize();
    buffer_used_ = 0;
    oldest_offset_ = 0;
    durable_offset_ = 0;
  }
  void uninitialize() {
    mutex_.uninitialize();
  }

  bool has_waiting_log() const { return buffer_used_ > 0; }

  char              buffer_[1 << 12];
  uint32_t          buffer_used_;
  uint64_t          oldest_offset_;
  uint64_t          durable_offset_;
  soc::SharedMutex  mutex_;
  soc::SharedPolling  logger_wakeup_;
};

class MetaLogBuffer : public Attachable<MetaLogControlBlock> {
 public:
  MetaLogBuffer() : Attachable<MetaLogControlBlock>() {}
  MetaLogBuffer(Engine* engine, MetaLogControlBlock* block)
    : Attachable<MetaLogControlBlock>(engine, block) {}

  void commit(BaseLogType* metalog, Epoch* commit_epoch);

  friend std::ostream& operator<<(std::ostream& o, const MetaLogBuffer& v);
};
}  // namespace log
}  // namespace foedus
#endif  // FOEDUS_LOG_META_LOG_BUFFER_HPP_