~drizzle-trunk/drizzle/development

/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2009 Sun Microsystems, Inc.

 *

 *  Authors:

 *

 *  Jay Pipes <joinfu@sun.com>

 *

 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

/**

 * @file

 *

 * Defines the API of a simple index for the transaction log

 */

#pragma once

#include "transaction_log.h"

#include "transaction_log_entry.h"

#include <pthread.h>

#include <string>

namespace drizzled { namespace message {class Transaction;}}

class TransactionLogIndex

{

public:

  explicit TransactionLogIndex(TransactionLog &in_log);

  ~TransactionLogIndex();

  /**

   * Returns the minimum end timestamp of a transaction

   * in the transaction log.

   */

  uint64_t getMinEndTimestamp() const;

  /**

   * Returns the maximum end timestamp of a transaction

   * in the transaction log.

   */

  uint64_t getMaxEndTimestamp() const;

  /**

   * Returns the minimum transaction ID of a transaction

   * in the transaction log.

   */

  uint64_t getMinTransactionId() const;

  /**

   * Returns the maximum transaction ID of a transaction

   * in the transaction log.

   */

  uint64_t getMaxTransactionId() const;

  /**

   * Returns the total number of entries in the transaction log

   */

  uint64_t getNumLogEntries() const;

  /**

   * Returns the total number of transaction entries in the transaction log

   */

  uint64_t getNumTransactionEntries() const;

  /**

   * Returns whether the index encountered an

   * error on its last action.

   */

  bool hasError() const;

  /**

   * Returns the current error message

   */

  const std::string &getErrorMessage() const;

  /**

   * Returns a reference to the index's collection

   * of log entry objects

   */

  TransactionLog::Entries &getEntries();

  /**

   * Returns a reference to the index's collection

   * of transaction entry objects

   */

  TransactionLog::TransactionEntries &getTransactionEntries();

  /**

   * Adds a new entry to the index of type Transaction message.

   *

   * @param[in] The transaction log entry

   * @param[in] The transaction message

   * @param[in] The checksum for the transaction message bytes

   */

  void addEntry(const TransactionLogEntry &entry,

                const drizzled::message::Transaction &transaction,

                uint32_t checksum);

  /**

   * Clears all data out of the transaction log

   * index.

   *

   * @note

   *

   * No locks are taken here.  Currently only used in debugging.

   */

  void clear();

  /* Some methods returning size in bytes of the index and its parts */

  size_t getTransactionEntriesSizeInBytes();

  size_t getEntriesSizeInBytes();

  size_t getSizeInBytes();

private:

  /**

   * Helper function to open/create the index from 

   * the transaction log.

   */

  void open();

  /**

   * Clears the internal error state

   */

  void clearError();

  TransactionLog &log; ///< The transaction log instance

  int index_file; ///< File descriptor for the transaction log on-disk index file

  const std::string index_file_path; ///< Filename of the on-disk transaction log index

  bool has_error; ///< Index is in error mode?

  std::string error_message; ///< Current error message

  uint64_t min_end_timestamp; ///< Minimum end timestamp in log

  uint64_t max_end_timestamp; ///< Maximim end timestamp in log

  uint64_t min_transaction_id; ///< Minimum transaction ID in log

  uint64_t max_transaction_id; ///< Maximum transaction ID in log

  TransactionLog::Entries entries; ///< Collection of information about the entries in the log

  TransactionLog::TransactionEntries transaction_entries; ///<

  pthread_mutex_t index_lock; ///< The global index lock

};