chert_database.h

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/* Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2002 Ananova Ltd
 * Copyright 2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Olly Betts
 * Copyright 2008 Lemur Consulting Ltd
 *
 * 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_CHERT_DATABASE_H
#define OM_HGUARD_CHERT_DATABASE_H

#include "backends/backends.h"
#include "backends/database.h"
#include "chert_dbstats.h"
#include "chert_positionlist.h"
#include "chert_postlist.h"
#include "chert_record.h"
#include "chert_spelling.h"
#include "chert_synonym.h"
#include "chert_termlisttable.h"
#include "chert_values.h"
#include "chert_version.h"
#include "../flint_lock.h"
#include "chert_types.h"
#include "backends/valuestats.h"

#include "noreturn.h"

#include "xapian/compactor.h"
#include "xapian/constants.h"

#include <map>
#include <vector>
#include <string>

class ChertTermList;
class ChertAllDocsPostList;
class RemoteConnection;

class ChertDatabase : public Xapian::Database::Internal {
    friend class ChertWritableDatabase;
    friend class ChertTermList;
    friend class ChertPostList;
    friend class ChertAllTermsList;
    friend class ChertAllDocsPostList;
    private:
        std::string db_dir;

        bool readonly;

        ChertVersion version_file;

        mutable ChertPostListTable postlist_table;

        ChertPositionListTable position_table;

        ChertTermListTable termlist_table;

        mutable ChertValueManager value_manager;

        mutable ChertSynonymTable synonym_table;

        mutable ChertSpellingTable spelling_table;

        ChertRecordTable record_table;

        FlintLock lock;

        unsigned int max_changesets;

        ChertDatabaseStats stats;

        bool database_exists();

        void create_and_open_tables(unsigned int blocksize);

        bool open_tables_consistent();

        void get_database_write_lock(int flags, bool creating);

        void open_tables(chert_revision_number_t revision);

        chert_revision_number_t get_next_revision_number() const;

        void set_revision_number(chert_revision_number_t new_revision);

        bool reopen();

        void close();

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

        void apply();

        void cancel();

        void send_whole_database(RemoteConnection & conn, double end_time);

        void get_changeset_revisions(const string & path,
                                     chert_revision_number_t * startrev,
                                     chert_revision_number_t * endrev) const;
    public:
        ChertDatabase(const string &db_dir_, int action = Xapian::DB_READONLY_,
                      unsigned int block_size = 0u);

        ~ChertDatabase();

        ChertCursor * get_postlist_cursor() const {
            return postlist_table.cursor_get();
        }

        chert_revision_number_t get_revision_number() const;

        Xapian::doccount get_doccount() const;
        Xapian::docid get_lastdocid() const;
        Xapian::totallength get_total_length() const;
        Xapian::termcount get_doclength(Xapian::docid did) const;
        Xapian::termcount get_unique_terms(Xapian::docid did) const;
        void get_freqs(const string & term,
                       Xapian::doccount * termfreq_ptr,
                       Xapian::termcount * collfreq_ptr) const;
        Xapian::doccount get_value_freq(Xapian::valueno slot) const;
        std::string get_value_lower_bound(Xapian::valueno slot) const;
        std::string get_value_upper_bound(Xapian::valueno slot) const;
        Xapian::termcount get_doclength_lower_bound() const;
        Xapian::termcount get_doclength_upper_bound() const;
        Xapian::termcount get_wdf_upper_bound(const string & term) const;
        bool term_exists(const string & tname) const;
        bool has_positions() const;

        LeafPostList * open_post_list(const string & tname) const;
        ValueList * open_value_list(Xapian::valueno slot) const;
        Xapian::Document::Internal * open_document(Xapian::docid did, bool lazy) 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;
        void write_changesets_to_fd(int fd,
                                    const string & start_revision,
                                    bool need_whole_db,
                                    Xapian::ReplicationInfo * info);
        string get_revision_info() const;
        string get_uuid() const;

        void request_document(Xapian::docid /*did*/) const;
        void readahead_for_query(const Xapian::Query &query);

        XAPIAN_NORETURN(void throw_termlist_table_close_exception() const);

        int get_backend_info(string * path) const {
            if (path) *path = db_dir;
            return BACKEND_CHERT;
        }

        void get_used_docid_range(Xapian::docid & first,
                                  Xapian::docid & last) const;

        bool locked() const;

        virtual bool has_uncommitted_changes() const;

        static void compact(Xapian::Compactor * compactor,
                            const char * destdir,
                            const std::vector<Xapian::Database::Internal *> & sources,
                            const std::vector<Xapian::docid> & offset,
                            size_t block_size,
                            Xapian::Compactor::compaction_level compaction,
                            unsigned flags,
                            Xapian::docid last_docid);
};

class ChertWritableDatabase : public ChertDatabase {
        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 map<Xapian::valueno, ValueStats> value_stats;

        mutable Xapian::doccount change_count;

        Xapian::doccount flush_threshold;

        mutable Xapian::Document::Internal * modify_shortcut_document;

        mutable Xapian::docid modify_shortcut_docid;

        void check_flush_threshold();

        void flush_postlist_changes() const;

        void close();

        void apply();

        void add_freq_delta(const string & tname,
                            Xapian::termcount_diff tf_delta,
                            Xapian::termcount_diff cf_delta);

        void insert_mod_plist(Xapian::docid did,
                              const string & tname,
                              Xapian::termcount wdf);

        void update_mod_plist(Xapian::docid did,
                              const string & tname,
                              char type,
                              Xapian::termcount wdf);


        void commit();

        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.
#ifndef _MSC_VER
        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);

        Xapian::Document::Internal * open_document(Xapian::docid did,
                                                   bool lazy) const;


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

        ~ChertWritableDatabase();

        Xapian::termcount get_doclength(Xapian::docid did) const;
        Xapian::termcount get_unique_terms(Xapian::docid did) const;
        void get_freqs(const string & term,
                       Xapian::doccount * termfreq_ptr,
                       Xapian::termcount * collfreq_ptr) const;
        Xapian::doccount get_value_freq(Xapian::valueno slot) const;
        std::string get_value_lower_bound(Xapian::valueno slot) const;
        std::string get_value_upper_bound(Xapian::valueno slot) const;
        bool term_exists(const string & tname) const;

        LeafPostList * open_post_list(const string & tname) const;
        ValueList * open_value_list(Xapian::valueno slot) 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);
        void invalidate_doc_object(Xapian::Document::Internal * obj) const;

        bool has_uncommitted_changes() const;
};

#endif /* OM_HGUARD_CHERT_DATABASE_H */