backends/flint/flint_database.h

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/* flint_database.h: C++ class definition for flint database
 *
 * Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2002 Ananova Ltd
 * Copyright 2002,2003,2004,2005,2006,2007 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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#ifndef OM_HGUARD_FLINT_DATABASE_H
#define OM_HGUARD_FLINT_DATABASE_H

#include "database.h"
#include "flint_positionlist.h"
#include "flint_postlist.h"
#include "flint_record.h"
#include "flint_spelling.h"
#include "flint_synonym.h"
#include "flint_termlisttable.h"
#include "flint_values.h"
#include "flint_version.h"
#include "flint_lock.h"

#include "flint_types.h"

#include <map>

class FlintTermList;
class FlintAllDocsPostList;

const int XAPIAN_DB_READONLY = 0;

class FlintDatabase : public Xapian::Database::Internal {
    friend class FlintWritableDatabase;
    friend class FlintTermList;
    friend class FlintPostList;
    friend class FlintAllTermsList;
    friend class FlintAllDocsPostList;
    private:
        std::string db_dir;

        bool readonly;

        FlintVersion version_file;

        mutable FlintPostListTable postlist_table;

        FlintPositionListTable position_table;

        FlintTermListTable termlist_table;

        FlintValueTable value_table;

        mutable FlintSynonymTable synonym_table;

        mutable FlintSpellingTable spelling_table;

        FlintRecordTable record_table;

        FlintLock lock;

        mutable flint_totlen_t total_length;

        mutable Xapian::docid lastdocid;

        void read_metainfo();

        bool database_exists();

        void create_and_open_tables(unsigned int blocksize);

        void open_tables_consistent();

        void get_database_write_lock();

        void open_tables(flint_revision_number_t revision);

        flint_revision_number_t get_revision_number() const;

        flint_revision_number_t get_next_revision_number() const;

        void set_revision_number(flint_revision_number_t new_revision);

        void reopen();

        void modifications_failed(flint_revision_number_t old_revision,
                                  flint_revision_number_t new_revision,
                                  const std::string & msg);

        void apply();

        void cancel();

    public:
        FlintDatabase(const string &db_dir_, int action = XAPIAN_DB_READONLY,
                       unsigned int block_size = 0u);

        ~FlintDatabase();

        Xapian::doccount  get_doccount() const;
        Xapian::docid get_lastdocid() const;
        Xapian::doclength get_avlength() const;
        Xapian::doclength get_doclength(Xapian::docid did) const;
        Xapian::doccount get_termfreq(const string & tname) const;
        Xapian::termcount get_collection_freq(const string & tname) const;
        bool term_exists(const string & tname) const;
        bool has_positions() const;

        LeafPostList * open_post_list(const string & tname) const;
        Xapian::Document::Internal * open_document(Xapian::docid did, bool lazy = false) const;

        PositionList * open_position_list(Xapian::docid did, const string & term) const;
        TermList * open_term_list(Xapian::docid did) const;
        TermList * open_allterms(const string & prefix) const;

        TermList * open_spelling_termlist(const string & word) const;
        TermList * open_spelling_wordlist() const;
        Xapian::doccount get_spelling_frequency(const string & word) const;

        TermList * open_synonym_termlist(const string & term) const;
        TermList * open_synonym_keylist(const string & prefix) const;

        string get_metadata(const string & key) const;
        TermList * open_metadata_keylist(const std::string &prefix) const;
};

class FlintWritableDatabase : public FlintDatabase {
        mutable map<string, pair<Xapian::termcount_diff, Xapian::termcount_diff> >
                freq_deltas;

        mutable map<Xapian::docid, Xapian::termcount> doclens;

        mutable map<string, map<Xapian::docid,
                                pair<char, Xapian::termcount> > > mod_plists;

        mutable Xapian::doccount change_count;

        Xapian::doccount flush_threshold;

        void flush_postlist_changes() const;


        void flush();

        void cancel();

        Xapian::docid add_document(const Xapian::Document & document);
        Xapian::docid add_document_(Xapian::docid did, const Xapian::Document & document);
        // Stop the default implementation of delete_document(term) and
        // replace_document(term) from being hidden.  This isn't really
        // a problem as we only try to call them through the base class
        // (where they aren't hidden) but some compilers generate a warning
        // about the hiding.
#if (!defined __GNUC__ && !defined _MSC_VER) || __GNUC__ > 2
        using Xapian::Database::Internal::delete_document;
        using Xapian::Database::Internal::replace_document;
#endif
        void delete_document(Xapian::docid did);
        void replace_document(Xapian::docid did, const Xapian::Document & document);

    public:
        FlintWritableDatabase(const string &dir, int action, int block_size);

        ~FlintWritableDatabase();

        Xapian::doclength get_doclength(Xapian::docid did) const;
        Xapian::doccount get_termfreq(const string & tname) const;
        Xapian::termcount get_collection_freq(const string & tname) const;
        bool term_exists(const string & tname) const;

        LeafPostList * open_post_list(const string & tname) const;
        TermList * open_allterms(const string & prefix) const;

        void add_spelling(const string & word, Xapian::termcount freqinc) const;
        void remove_spelling(const string & word, Xapian::termcount freqdec) const;
        TermList * open_spelling_wordlist() const;

        TermList * open_synonym_keylist(const string & prefix) const;
        void add_synonym(const string & word, const string & synonym) const;
        void remove_synonym(const string & word, const string & synonym) const;
        void clear_synonyms(const string & word) const;

        void set_metadata(const string & key, const string & value);
};

#endif /* OM_HGUARD_FLINT_DATABASE_H */

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