xapian-core/include/xapian/valuesetmatchdecider.h

   1 /** @file valuesetmatchdecider.h
   2  * @brief MatchDecider subclass for filtering results by value.
   3  */
   4 /* Copyright 2008 Lemur Consulting Ltd
   5  * Copyright 2008,2009,2011,2013,2014,2017 Olly Betts
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (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
  20  * USA
  21  */
  22
  23 #ifndef XAPIAN_INCLUDED_VALUESETMATCHDECIDER_H
  24 #define XAPIAN_INCLUDED_VALUESETMATCHDECIDER_H
  25
  26 #if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
  27 # error "Never use <xapian/valuesetmatchdecider.h> directly; include <xapian.h> instead."
  28 #endif
  29
  30 #include <xapian/matchdecider.h>
  31 #include <xapian/types.h>
  32 #include <xapian/visibility.h>
  33
  34 #include <string>
  35 #include <set>
  36
  37 namespace Xapian {
  38
  39 class Document;
  40
  41 /** MatchDecider filtering results based on whether document values are in a
  42  *  user-defined set.
  43  */
  44 class XAPIAN_VISIBILITY_DEFAULT ValueSetMatchDecider : public MatchDecider {
  45     /** Set of values to test for. */
  46     std::set<std::string> testset;
  47
  48     /** The value slot to look in. */
  49     valueno valuenum;
  50
  51     /** Whether to include or exclude documents with the specified values.
  52      *
  53      *  If true, documents with a value in the set are returned.
  54      *  If false, documents with a value not in the set are returned.
  55      */
  56     bool inclusive;
  57
  58   public:
  59     /** Construct a ValueSetMatchDecider.
  60      *
  61      *  @param slot The value slot number to look in.
  62      *
  63      *  @param inclusive_ If true, match decider accepts documents which have a
  64      *  value in the specified slot which is a member of the test set; if
  65      *  false, match decider accepts documents which do not have a value in the
  66      *  specified slot.
  67      */
  68     ValueSetMatchDecider(Xapian::valueno slot, bool inclusive_)
  69         : valuenum(slot), inclusive(inclusive_) { }
  70
  71     /** Add a value to the test set.
  72      *
  73      *  @param value The value to add to the test set.
  74      */
  75     void add_value(const std::string& value)
  76     {
  77         testset.insert(value);
  78     }
  79
  80     /** Remove a value from the test set.
  81      *
  82      *  @param value The value to remove from the test set.
  83      */
  84     void remove_value(const std::string& value)
  85     {
  86         testset.erase(value);
  87     }
  88
  89     /** Decide whether we want a particular document to be in the MSet.
  90      *
  91      *  @param doc      The document to test.
  92      *  @return         true if the document is acceptable, or false if the
  93      *                  document should be excluded from the MSet.
  94      */
  95     bool operator()(const Xapian::Document& doc) const;
  96 };
  97
  98 }
  99
 100 #endif /* XAPIAN_INCLUDED_VALUESETMATCHDECIDER_H */