CellCacheScanner.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_RangeServer_CellCacheScanner_h
#define Hypertable_RangeServer_CellCacheScanner_h

#include "CellCache.h"
#include "CellListScanner.h"
#include "ScanContext.h"

namespace Hypertable {

  class CellCacheScanner : public CellListScanner {
  public:
    CellCacheScanner(CellCachePtr cellcache, ScanContext *scan_ctx);
    virtual ~CellCacheScanner() { return; }
    virtual void forward();
    virtual bool get(Key &key, ByteString &value);

    virtual int64_t get_disk_read() { return 0; }

    typedef std::map<const SerializedKey, uint32_t> CellCacheMap;

  private:

    bool internal_get();
    void internal_forward();
    void load_entry_cache();

    class CellCacheEntry {
    public:
      CellCacheEntry() : value(0) { };
      Key         key;
      ByteString  value;
    };

    CellCache::CellMap::iterator   m_start_iter;
    CellCache::CellMap::iterator   m_end_iter;
    CellCache::CellMap::iterator   m_cur_iter;
    CellCacheMap::iterator         m_delete_iter;
    CellCachePtr                   m_cell_cache_ptr;
    std::mutex                    &m_cell_cache_mutex;
    CellCacheEntry                 m_cur_entry;
    std::vector<CellCacheEntry>    m_entry_cache;
    size_t                         m_entry_cache_next {};
    CellCacheMap                   m_deletes;
    bool                           m_in_deletes {};
    bool                           m_eos {};
    bool                           m_keys_only {};
  };
}

#endif // Hypertable_RangeServer_CellCacheScanner_h