xapian-core/matcher/localsubmatch.h

   1 /** @file localsubmatch.h
   2  *  @brief SubMatch class for a local database.
   3  */
   4 /* Copyright (C) 2006,2007,2009,2010,2011,2013,2014,2015,2016 Olly Betts
   5  * Copyright (C) 2007 Lemur Consulting Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  20  */
  21
  22 #ifndef XAPIAN_INCLUDED_LOCALSUBMATCH_H
  23 #define XAPIAN_INCLUDED_LOCALSUBMATCH_H
  24
  25 #include "backends/databaseinternal.h"
  26 #include "api/leafpostlist.h"
  27 #include "api/queryinternal.h"
  28 #include "xapian/enquire.h"
  29 #include "xapian/weight.h"
  30
  31 #include <map>
  32
  33 class LeafPostList;
  34 class PostListTree;
  35
  36 class LocalSubMatch {
  37     /// Don't allow assignment.
  38     LocalSubMatch& operator=(const LocalSubMatch &) = delete;
  39
  40     /// Don't allow copying.
  41     LocalSubMatch(const LocalSubMatch &) = delete;
  42
  43     /// The statistics for the collection.
  44     Xapian::Weight::Internal* total_stats;
  45
  46     /// The original query before any rearrangement.
  47     Xapian::Query query;
  48
  49     /// The query length (used by some weighting schemes).
  50     Xapian::termcount qlen;
  51
  52     /// The (sub-)Database we're searching.
  53     const Xapian::Database::Internal* db;
  54
  55     /// Weight object (used as a factory by calling create on it).
  56     const Xapian::Weight* wt_factory;
  57
  58     /// Do any of the subdatabases have positional information?
  59     bool full_db_has_positions;
  60
  61   public:
  62     /// Constructor.
  63     LocalSubMatch(const Xapian::Database::Internal* db_,
  64                   const Xapian::Query& query_,
  65                   Xapian::termcount qlen_,
  66                   const Xapian::Weight* wt_factory_,
  67                   bool full_db_has_positions_)
  68         : total_stats(NULL), query(query_), qlen(qlen_), db(db_),
  69           wt_factory(wt_factory_),
  70           full_db_has_positions(full_db_has_positions_)
  71     {}
  72
  73     /** Fetch and collate statistics.
  74      *
  75      *  Before we can calculate term weights we need to fetch statistics from
  76      *  each database involved and collate them.
  77      *
  78      *  @param rset     The RSet for this shard.
  79      *  @param stats    Weight::Internal object to add the statistics to.
  80      */
  81     void prepare_match(const Xapian::RSet& rset,
  82                        Xapian::Weight::Internal& stats)
  83     {
  84         stats.accumulate_stats(*db, rset);
  85     }
  86
  87     /** Set the collated statistics.
  88      *
  89      *  These will be used when generating the PostList tree.
  90      */
  91     void start_match(Xapian::Weight::Internal& total_stats_)
  92     {
  93         total_stats = &total_stats_;
  94     }
  95
  96     /// Get PostList.
  97     PostList * get_postlist(PostListTree* matcher,
  98                             Xapian::termcount* total_subqs_ptr);
  99
 100     /** Convert a postlist into a synonym postlist.
 101      */
 102     PostList * make_synonym_postlist(PostList* or_pl, double factor);
 103
 104     PostList * open_post_list(const std::string& term,
 105                               Xapian::termcount wqf,
 106                               double factor,
 107                               bool need_positions,
 108                               bool in_synonym,
 109                               Xapian::Internal::QueryOptimiser* qopt,
 110                               bool lazy_weight);
 111 };
 112
 113 #endif /* XAPIAN_INCLUDED_LOCALSUBMATCH_H */