xapian-core/matcher/valuestreamdocument.h

   1 /** @file
   2  * @brief A document which gets its values from a ValueStreamManager.
   3  */
   4 /* Copyright (C) 2009,2011,2014 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (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 USA
  19  */
  20
  21 #ifndef XAPIAN_INCLUDED_VALUESTREAMDOCUMENT_H
  22 #define XAPIAN_INCLUDED_VALUESTREAMDOCUMENT_H
  23
  24 #include "backends/document.h"
  25 #include "backends/valuelist.h"
  26 #include "omassert.h"
  27 #include "xapian/database.h"
  28 #include "xapian/types.h"
  29
  30 #include <map>
  31
  32 /// A document which gets its values from a ValueStreamManager.
  33 class ValueStreamDocument : public Xapian::Document::Internal {
  34     /// Don't allow assignment.
  35     void operator=(const ValueStreamDocument &);
  36
  37     /// Don't allow copying.
  38     ValueStreamDocument(const ValueStreamDocument &);
  39
  40     mutable std::map<Xapian::valueno, ValueList *> valuelists;
  41
  42     Xapian::Database db;
  43
  44     size_t current;
  45
  46     mutable Xapian::Document::Internal * doc;
  47
  48   public:
  49     explicit ValueStreamDocument(const Xapian::Database & db_)
  50         : Internal(db_.internal[0], 0), db(db_), current(0), doc(NULL) { }
  51
  52     void new_subdb(int n);
  53
  54     ~ValueStreamDocument();
  55
  56     void set_document(Xapian::docid did_) {
  57         // did needs to be the document id in the sub-database.
  58         size_t multiplier = db.internal.size();
  59         did = (did_ - 1) / multiplier + 1;
  60         AssertEq(current, (did_ - 1) % multiplier);
  61         delete doc;
  62         doc = NULL;
  63     }
  64
  65     // Optimise away the virtual call when the matcher wants to know a value.
  66     std::string get_value(Xapian::valueno slot) const {
  67         return ValueStreamDocument::do_get_value(slot);
  68     }
  69
  70   private:
  71     /** Implementation of virtual methods @{ */
  72     std::string do_get_value(Xapian::valueno slot) const;
  73     void do_get_all_values(std::map<Xapian::valueno, std::string> & values_) const;
  74     std::string do_get_data() const;
  75     /** @} */
  76 };
  77
  78 #endif // XAPIAN_INCLUDED_VALUESTREAMDOCUMENT_H