valuestreamdocument.h

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/* Copyright (C) 2009,2011,2014,2017 Olly Betts
 *
 * 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, see
 * <https://www.gnu.org/licenses/>.
 */
 
#ifndef XAPIAN_INCLUDED_VALUESTREAMDOCUMENT_H
#define XAPIAN_INCLUDED_VALUESTREAMDOCUMENT_H
 
#include "backends/documentinternal.h"
#include "backends/multi.h"
#include "backends/multi/multi_database.h"
#include "backends/valuelist.h"
#include "omassert.h"
#include "xapian/database.h"
#include "xapian/types.h"
 
#include <map>
 
class ValueStreamDocument : public Xapian::Document::Internal {
    void operator=(const ValueStreamDocument &);
 
    ValueStreamDocument(const ValueStreamDocument &);
 
    mutable std::map<Xapian::valueno, ValueList *> valuelists;
 
    Xapian::Database db;
 
    Xapian::doccount current = 0;
 
    Xapian::doccount n_shards;
 
    mutable Xapian::Document::Internal * doc = NULL;
 
    ValueStreamDocument(const Xapian::Database& db_, Xapian::doccount n_shards_)
        : Internal(n_shards_ == 1 ?
                   db_.internal.get() :
                   static_cast<MultiDatabase*>(db_.internal.get())->shards[0],
                   0),
          db(db_),
          n_shards(n_shards_) {}
 
  public:
    explicit ValueStreamDocument(const Xapian::Database& db_)
        : ValueStreamDocument(db_, db_.internal->size()) {}
 
    void new_shard(Xapian::doccount n);
 
    ~ValueStreamDocument();
 
    void set_shard_document(Xapian::docid shard_did) {
        if (did != shard_did) {
            did = shard_did;
            delete doc;
            doc = NULL;
        }
    }
 
    void set_document(Xapian::docid did_) {
        AssertEq(current, shard_number(did_, n_shards));
        set_shard_document(shard_docid(did_, n_shards));
    }
 
    // Optimise away the virtual call when the matcher wants to know a value.
    std::string get_value(Xapian::valueno slot) const {
        return ValueStreamDocument::fetch_value(slot);
    }
 
  protected:
    std::string fetch_value(Xapian::valueno slot) const;
    void fetch_all_values(std::map<Xapian::valueno, std::string> & values_) const;
    std::string fetch_data() const;
};
 
#endif // XAPIAN_INCLUDED_VALUESTREAMDOCUMENT_H