postingsource.h

Go to the documentation of this file.

/* Copyright (C) 2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Olly Betts
 * Copyright (C) 2008,2009 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_POSTINGSOURCE_H
#define XAPIAN_INCLUDED_POSTINGSOURCE_H

#if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
# error Never use <xapian/postingsource.h> directly; include <xapian.h> instead.
#endif

#include <xapian/attributes.h>
#include <xapian/database.h>
#include <xapian/deprecated.h>
#include <xapian/intrusive_ptr.h>
#include <xapian/postingiterator.h>
#include <xapian/types.h>
#include <xapian/valueiterator.h>
#include <xapian/visibility.h>

#include <string>
#include <map>

namespace Xapian {

class Registry;

class XAPIAN_VISIBILITY_DEFAULT PostingSource
    : public Xapian::Internal::opt_intrusive_base {
    void operator=(const PostingSource &);

    PostingSource(const PostingSource &);

    double max_weight_;

    void * matcher_;

  public:
    XAPIAN_NOTHROW(PostingSource())
        : max_weight_(0), matcher_(NULL) { }

    void register_matcher_(void * matcher) { matcher_ = matcher; }

    // Destructor.
    virtual ~PostingSource();

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

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

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

    void set_maxweight(double max_weight);

    double XAPIAN_NOTHROW(get_maxweight() const) { return max_weight_; }

    virtual double get_weight() const;

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

    virtual void next(double min_wt) = 0;

    virtual void skip_to(Xapian::docid did, double min_wt);

    virtual bool check(Xapian::docid did, double min_wt);

    virtual bool at_end() const = 0;

    virtual PostingSource * clone() const;

    virtual std::string name() const;

    virtual std::string serialise() const;

    virtual PostingSource * unserialise(const std::string &serialised) const;

    virtual PostingSource * unserialise_with_registry(const std::string &serialised,
                                      const Registry & registry) const;

    virtual void init(const Database & db) = 0;

    virtual std::string get_description() const;

    PostingSource * release() {
        opt_intrusive_base::release();
        return this;
    }

    const PostingSource * release() const {
        opt_intrusive_base::release();
        return this;
    }
};


class XAPIAN_VISIBILITY_DEFAULT ValuePostingSource : public PostingSource {
    // We want to give a deprecation warning for uses of the members from user
    // code, but we also want to be able to inline functions to access them,
    // without those functions generating deprecated warnings.  To achieve
    // this, we make the old names references to members with a "real_" prefix
    // and then use the latter in the inlined accessor functions.  The
    // constructor initialises all the references to point to their "real_"
    // counterparts.
    Xapian::Database real_db;

    Xapian::valueno real_slot;

    Xapian::ValueIterator real_value_it;

    bool real_started;

    Xapian::doccount real_termfreq_min;

    Xapian::doccount real_termfreq_est;

    Xapian::doccount real_termfreq_max;

  protected:
    XAPIAN_DEPRECATED(Xapian::Database& db);

    XAPIAN_DEPRECATED(Xapian::valueno& slot);

    XAPIAN_DEPRECATED(Xapian::ValueIterator& value_it);

    XAPIAN_DEPRECATED(bool& started);

    XAPIAN_DEPRECATED(Xapian::doccount& termfreq_min);

    XAPIAN_DEPRECATED(Xapian::doccount& termfreq_est);

    XAPIAN_DEPRECATED(Xapian::doccount& termfreq_max);

  public:
    explicit ValuePostingSource(Xapian::valueno slot_);

    Xapian::doccount get_termfreq_min() const;
    Xapian::doccount get_termfreq_est() const;
    Xapian::doccount get_termfreq_max() const;

    void next(double min_wt);
    void skip_to(Xapian::docid min_docid, double min_wt);
    bool check(Xapian::docid min_docid, double min_wt);

    bool at_end() const;

    Xapian::docid get_docid() const;

    void init(const Database & db_);

    Xapian::Database get_database() const { return real_db; }

    Xapian::valueno get_slot() const { return real_slot; }

    std::string get_value() const { return *real_value_it; }

    void done() {
        real_value_it = real_db.valuestream_end(real_slot);
        real_started = true;
    }

    bool get_started() const { return real_started; }

    void set_termfreq_min(Xapian::doccount termfreq_min_) {
        real_termfreq_min = termfreq_min_;
    }

    void set_termfreq_est(Xapian::doccount termfreq_est_) {
        real_termfreq_est = termfreq_est_;
    }

    void set_termfreq_max(Xapian::doccount termfreq_max_) {
        real_termfreq_max = termfreq_max_;
    }
};


class XAPIAN_VISIBILITY_DEFAULT ValueWeightPostingSource
        : public ValuePostingSource {
  public:
    explicit ValueWeightPostingSource(Xapian::valueno slot_);

    double get_weight() const;
    ValueWeightPostingSource * clone() const;
    std::string name() const;
    std::string serialise() const;
    ValueWeightPostingSource * unserialise(const std::string &serialised) const;
    void init(const Database & db_);

    std::string get_description() const;
};


class XAPIAN_VISIBILITY_DEFAULT DecreasingValueWeightPostingSource
        : public Xapian::ValueWeightPostingSource {
  protected:
    Xapian::docid range_start;

    Xapian::docid range_end;

    double curr_weight;

    bool items_at_end;

    void skip_if_in_range(double min_wt);

  public:
    DecreasingValueWeightPostingSource(Xapian::valueno slot_,
                                       Xapian::docid range_start_ = 0,
                                       Xapian::docid range_end_ = 0);

    double get_weight() const;
    DecreasingValueWeightPostingSource * clone() const;
    std::string name() const;
    std::string serialise() const;
    DecreasingValueWeightPostingSource * unserialise(const std::string &serialised) const;
    void init(const Xapian::Database & db_);

    void next(double min_wt);
    void skip_to(Xapian::docid min_docid, double min_wt);
    bool check(Xapian::docid min_docid, double min_wt);

    std::string get_description() const;
};


class XAPIAN_VISIBILITY_DEFAULT ValueMapPostingSource
        : public ValuePostingSource {
    double default_weight;

    double max_weight_in_map;

    std::map<std::string, double> weight_map;

  public:
    explicit ValueMapPostingSource(Xapian::valueno slot_);

    void add_mapping(const std::string &key, double wt);

    void clear_mappings();

    void set_default_weight(double wt);

    double get_weight() const;
    ValueMapPostingSource * clone() const;
    std::string name() const;
    std::string serialise() const;
    ValueMapPostingSource * unserialise(const std::string &serialised) const;
    void init(const Database & db_);

    std::string get_description() const;
};


class XAPIAN_VISIBILITY_DEFAULT FixedWeightPostingSource : public PostingSource {
    Xapian::Database db;

    Xapian::doccount termfreq;

    Xapian::PostingIterator it;

    bool started;

    Xapian::docid check_docid;

  public:
    explicit FixedWeightPostingSource(double wt);

    Xapian::doccount get_termfreq_min() const;
    Xapian::doccount get_termfreq_est() const;
    Xapian::doccount get_termfreq_max() const;

    double get_weight() const;

    void next(double min_wt);
    void skip_to(Xapian::docid min_docid, double min_wt);
    bool check(Xapian::docid min_docid, double min_wt);

    bool at_end() const;

    Xapian::docid get_docid() const;

    FixedWeightPostingSource * clone() const;
    std::string name() const;
    std::string serialise() const;
    FixedWeightPostingSource * unserialise(const std::string &serialised) const;
    void init(const Database & db_);

    std::string get_description() const;
};

}

#endif // XAPIAN_INCLUDED_POSTINGSOURCE_H