xapian-core/backends/glass/glass_alltermslist.h

   1 /** @file
   2  * @brief A termlist containing all terms in a glass database.
   3  */
   4 /* Copyright (C) 2005,2007,2008,2009,2010,2011,2024 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
  19  * USA
  20  */
  21
  22 #ifndef XAPIAN_INCLUDED_GLASS_ALLTERMSLIST_H
  23 #define XAPIAN_INCLUDED_GLASS_ALLTERMSLIST_H
  24
  25 #include "backends/alltermslist.h"
  26 #include "glass_database.h"
  27 #include "glass_postlist.h"
  28
  29 #include <string_view>
  30
  31 class GlassCursor;
  32
  33 class GlassAllTermsList : public AllTermsList {
  34     /// Copying is not allowed.
  35     GlassAllTermsList(const GlassAllTermsList &);
  36
  37     /// Assignment is not allowed.
  38     void operator=(const GlassAllTermsList &);
  39
  40     /// Keep a reference to our database to stop it being deleted.
  41     Xapian::Internal::intrusive_ptr<const GlassDatabase> database;
  42
  43     /** A cursor which runs through the postlist table reading termnames from
  44      *  the keys.
  45      */
  46     GlassCursor * cursor;
  47
  48     /// The prefix to restrict the terms to.
  49     std::string prefix;
  50
  51     /** The term frequency of the term at the current position.
  52      *
  53      *  If this value is zero, then we haven't read the term frequency for the
  54      *  current term yet.  We need to call read_termfreq() to read this.
  55      */
  56     mutable Xapian::doccount termfreq;
  57
  58     /// Read and cache the term frequency.
  59     void read_termfreq() const;
  60
  61   public:
  62     GlassAllTermsList(Xapian::Internal::intrusive_ptr<const GlassDatabase> database_,
  63                       std::string_view prefix_)
  64         : database(database_), cursor(NULL), prefix(prefix_), termfreq(0) { }
  65
  66     /// Destructor.
  67     ~GlassAllTermsList();
  68
  69     Xapian::termcount get_approx_size() const;
  70
  71     /** Returns the term frequency of the current term.
  72      *
  73      *  Either next() or skip_to() must have been called before this
  74      *  method can be called.
  75      */
  76     Xapian::doccount get_termfreq() const;
  77
  78     /// Advance to the next term in the list.
  79     TermList * next();
  80
  81     /// Advance to the first term which is >= tname.
  82     TermList* skip_to(std::string_view tname);
  83 };
  84
  85 #endif /* XAPIAN_INCLUDED_GLASS_ALLTERMSLIST_H */