postlist.h

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/* Copyright (C) 2007,2008,2009,2011,2015,2017 Olly Betts
 * Copyright (C) 2009 Lemur Consulting Ltd
 *
 * 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
 */

#ifndef XAPIAN_INCLUDED_POSTLIST_H
#define XAPIAN_INCLUDED_POSTLIST_H

#include <string>

#include "xapian/intrusive_ptr.h"
#include <xapian/types.h>
#include <xapian/postingiterator.h>

#include "backends/positionlist.h"
#include "weight/weightinternal.h"

class OrPositionList;

class Xapian::PostingIterator::Internal : public Xapian::Internal::intrusive_base {
    void operator=(const Internal &);

    Internal(const Internal &);

  protected:
    Internal() { }

  public:
    virtual ~Internal();

    virtual Xapian::doccount get_termfreq_min() const = 0;

    virtual Xapian::doccount get_termfreq_max() const = 0;

    virtual Xapian::doccount get_termfreq_est() const = 0;

    virtual TermFreqs get_termfreq_est_using_stats(
        const Xapian::Weight::Internal & stats) const;

    virtual double get_maxweight() const = 0;

    virtual Xapian::docid get_docid() const = 0;

    virtual Xapian::termcount get_doclength() const = 0;
    /* FIXME: Once flint has been retired, we should probably strip out
     * PostList::get_doclength() and just fetch it from the DB directly.
     */

    virtual Xapian::termcount get_unique_terms() const = 0;

    virtual Xapian::termcount get_wdf() const;

    virtual double get_weight() const = 0;

    virtual const std::string * get_sort_key() const;

    virtual const std::string * get_collapse_key() const;

    virtual bool at_end() const = 0;

    virtual double recalc_maxweight() = 0;

    virtual PositionList * read_position_list();

    virtual PositionList * open_position_list() const;

    virtual Internal * next(double w_min) = 0;

    virtual Internal * skip_to(Xapian::docid did, double w_min) = 0;

    virtual Internal * check(Xapian::docid did, double w_min, bool &valid);

    Internal * next() { return next(0.0); }

    Internal * skip_to(Xapian::docid did) { return skip_to(did, 0.0); }

    virtual Xapian::termcount count_matching_subqs() const;

    virtual void gather_position_lists(OrPositionList* orposlist);

    virtual std::string get_description() const = 0;
};

// In the external API headers, this class is Xapian::PostingIterator::Internal,
// but in the library code it's still known as "PostList" in most places.
typedef Xapian::PostingIterator::Internal PostList;

#endif // XAPIAN_INCLUDED_POSTLIST_H