queryinternal.h

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/* Copyright (C) 2011-2026 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_QUERYINTERNAL_H
#define XAPIAN_INCLUDED_QUERYINTERNAL_H
 
#include "api/editdistance.h"
#include "queryvector.h"
#include "stringutils.h"
#include "xapian/intrusive_ptr.h"
#include "xapian/query.h"
 
const Xapian::termcount DEFAULT_ELITE_SET_SIZE = 10;
 
namespace Xapian {
namespace Internal {
 
class PostList;
struct PostListAndEstimate;
class QueryOptimiser;
 
class QueryTerm : public Query::Internal {
    std::string term;
 
    Xapian::termcount wqf;
 
    Xapian::termpos pos;
 
  public:
    // Construct a "MatchAll" QueryTerm.
    QueryTerm() : term(), wqf(1), pos(0) { }
 
    QueryTerm(std::string_view term_,
              Xapian::termcount wqf_,
              Xapian::termpos pos_)
        : term(term_), wqf(wqf_), pos(pos_) { }
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    const std::string & get_term() const { return term; }
 
    termcount get_wqf() const { return wqf; }
 
    termpos get_pos() const { return pos; }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    termcount get_length() const noexcept XAPIAN_PURE_FUNCTION {
        return wqf;
    }
 
    void serialise(std::string & result) const;
 
    std::string get_description() const;
 
    void gather_terms(void * void_terms) const;
};
 
class QueryPostingSource : public Query::Internal {
    Xapian::Internal::opt_intrusive_ptr<PostingSource> source;
 
  public:
    explicit QueryPostingSource(PostingSource * source_);
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void serialise(std::string & result) const;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    std::string get_description() const;
};
 
class QueryScaleWeight : public Query::Internal {
    double scale_factor;
 
    Query subquery;
 
  public:
    QueryScaleWeight(double factor, const Query & subquery_);
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    termcount get_length() const noexcept XAPIAN_PURE_FUNCTION {
        return subquery.internal->get_length();
    }
 
    void serialise(std::string & result) const;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
    size_t get_num_subqueries() const noexcept XAPIAN_PURE_FUNCTION;
    const Query get_subquery(size_t n) const;
 
    std::string get_description() const;
 
    void gather_terms(void * void_terms) const;
};
 
class QueryValueBase : public Query::Internal {
  protected:
    Xapian::valueno slot;
 
  public:
    explicit QueryValueBase(Xapian::valueno slot_)
        : slot(slot_) { }
 
    Xapian::valueno get_slot() const { return slot; }
};
 
class QueryValueRange : public QueryValueBase {
    std::string begin, end;
 
  public:
    QueryValueRange(Xapian::valueno slot_,
                    std::string_view begin_,
                    std::string_view end_)
        : QueryValueBase(slot_), begin(begin_), end(end_) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void serialise(std::string & result) const;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    std::string get_description() const;
};
 
class QueryValueLE : public QueryValueBase {
    std::string limit;
 
  public:
    QueryValueLE(Xapian::valueno slot_, std::string_view limit_)
        : QueryValueBase(slot_), limit(limit_) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void serialise(std::string & result) const;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    std::string get_description() const;
};
 
class QueryValueGE : public QueryValueBase {
    std::string limit;
 
  public:
    QueryValueGE(Xapian::valueno slot_, std::string_view limit_)
        : QueryValueBase(slot_), limit(limit_) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void serialise(std::string & result) const;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    std::string get_description() const;
};
 
class QueryBranch : public Query::Internal {
    virtual Xapian::Query::op get_op() const = 0;
 
  protected:
    QueryVector subqueries;
 
    explicit QueryBranch(size_t n_subqueries) : subqueries(n_subqueries) { }
 
    void serialise_(std::string & result, Xapian::termcount parameter = 0) const;
 
    void do_bool_or_like(OrContext& ctx,
                         QueryOptimiser* qopt,
                         TermFreqs* termfreqs,
                         size_t first = 0) const;
 
    void do_or_like(OrContext& ctx, QueryOptimiser* qopt, double factor,
                    TermFreqs* termfreqs,
                    Xapian::termcount elite_set_size = 0, size_t first = 0,
                    bool keep_zero_weight = true) const;
 
    PostListAndEstimate do_synonym(QueryOptimiser* qopt,
                                   double factor,
                                   TermFreqs* termfreqs) const;
 
    PostListAndEstimate do_max(QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    const std::string get_description_helper(const char * op,
                                             Xapian::termcount window = 0) const;
 
  public:
    termcount get_length() const noexcept XAPIAN_PURE_FUNCTION;
 
    void serialise(std::string & result) const;
 
    void gather_terms(void * void_terms) const;
 
    virtual void add_subquery(const Xapian::Query & subquery) = 0;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
    size_t get_num_subqueries() const noexcept XAPIAN_PURE_FUNCTION;
    const Query get_subquery(size_t n) const;
 
    virtual Query::Internal * done() = 0;
};
 
class QueryAndLike : public QueryBranch {
  protected:
    explicit QueryAndLike(size_t num_subqueries_)
        : QueryBranch(num_subqueries_) { }
 
  public:
    void add_subquery(const Xapian::Query & subquery);
 
    Query::Internal * done();
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
};
 
class QueryOrLike : public QueryBranch {
  protected:
    explicit QueryOrLike(size_t num_subqueries_)
        : QueryBranch(num_subqueries_) { }
 
  public:
    void add_subquery(const Xapian::Query & subquery);
 
    Query::Internal * done();
};
 
class QueryAnd : public QueryAndLike {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryAnd(size_t n_subqueries) : QueryAndLike(n_subqueries) { }
 
    std::string get_description() const;
};
 
class QueryOr : public QueryOrLike {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryOr(size_t n_subqueries) : QueryOrLike(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void postlist_sub_or_like(OrContext& ctx, QueryOptimiser* qopt,
                              double factor,
                              TermFreqs* termfreqs,
                              bool keep_zero_weight) const;
 
    void postlist_sub_bool_or_like(OrContext& ctx,
                                   QueryOptimiser* qopt,
                                   TermFreqs* termfreqs) const;
 
    std::string get_description() const;
};
 
class QueryAndNot : public QueryBranch {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryAndNot(size_t n_subqueries) : QueryBranch(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    void add_subquery(const Xapian::Query & subquery);
 
    Query::Internal * done();
 
    std::string get_description() const;
};
 
class QueryXor : public QueryOrLike {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryXor(size_t n_subqueries) : QueryOrLike(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void postlist_sub_xor(XorContext& ctx,
                          QueryOptimiser* qopt,
                          double factor,
                          TermFreqs* termfreqs) const;
 
    std::string get_description() const;
};
 
class QueryAndMaybe : public QueryBranch {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryAndMaybe(size_t n_subqueries) : QueryBranch(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    void add_subquery(const Xapian::Query & subquery);
 
    Query::Internal * done();
 
    std::string get_description() const;
};
 
class QueryFilter : public QueryAndLike {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryFilter(size_t n_subqueries) : QueryAndLike(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    std::string get_description() const;
};
 
class QueryWindowed : public QueryAndLike {
  protected:
    Xapian::termcount window;
 
    QueryWindowed(size_t n_subqueries, Xapian::termcount window_)
        : QueryAndLike(n_subqueries), window(window_) { }
 
    bool postlist_windowed(Xapian::Query::op op, AndContext& ctx,
                           QueryOptimiser* qopt, double factor,
                           TermFreqs* termfreqs) const;
 
  public:
    size_t get_window() const { return window; }
 
    Query::Internal * done();
};
 
class QueryNear : public QueryWindowed {
    Xapian::Query::op get_op() const;
 
  public:
    QueryNear(size_t n_subqueries, Xapian::termcount window_)
        : QueryWindowed(n_subqueries, window_) { }
 
    void serialise(std::string & result) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    std::string get_description() const;
};
 
class QueryPhrase : public QueryWindowed {
    Xapian::Query::op get_op() const;
 
  public:
    QueryPhrase(size_t n_subqueries, Xapian::termcount window_)
        : QueryWindowed(n_subqueries, window_) { }
 
    void serialise(std::string & result) const;
 
    bool postlist_sub_and_like(AndContext& ctx,
                               QueryOptimiser* qopt,
                               double factor,
                               TermFreqs* termfreqs) const;
 
    std::string get_description() const;
};
 
class QueryEliteSet : public QueryOrLike {
    Xapian::Query::op get_op() const;
 
    Xapian::termcount set_size;
 
  public:
    QueryEliteSet(size_t n_subqueries, Xapian::termcount set_size_)
        : QueryOrLike(n_subqueries),
          set_size(set_size_ ? set_size_ : DEFAULT_ELITE_SET_SIZE) { }
 
    void serialise(std::string & result) const;
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void postlist_sub_or_like(OrContext& ctx,
                              QueryOptimiser* qopt,
                              double factor,
                              TermFreqs* termfreqs,
                              bool keep_zero_weight) const;
 
    std::string get_description() const;
};
 
class QuerySynonym : public QueryOrLike {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QuerySynonym(size_t n_subqueries) : QueryOrLike(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    Query::Internal * done();
 
    std::string get_description() const;
};
 
class QueryMax : public QueryOrLike {
    Xapian::Query::op get_op() const;
 
  public:
    explicit QueryMax(size_t n_subqueries) : QueryOrLike(n_subqueries) { }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    std::string get_description() const;
};
 
class QueryWildcard : public Query::Internal {
    std::string pattern;
 
    Xapian::termcount max_expansion;
 
    int flags;
 
    Query::op combiner;
 
    size_t head = 0, tail = 0, min_len = 0, max_len = 0;
 
    // If candidate.size() >= min_len && candidate.size() < min_check_len then
    // we don't need to actually do the pattern check since the length and
    // head/tail checks are enough.
    //
    // This optimises cases `*` or `*?` or `?*` (which covers a lot of common
    // cases) and also a pattern where there's no `*` and a single `?` where
    // we only need to check the pattern when candidate.size() > min_len.
    //
    // Note that we can't handle cases like `*??` here since `?` matches a
    // single UTF-8 character, which can be more than one byte.
    size_t min_check_len = size_t(-1);
 
    std::string prefix, suffix;
 
    bool test_wildcard_(const std::string& candidate, size_t o, size_t p,
                        size_t i) const;
 
  public:
    QueryWildcard(std::string_view pattern_,
                  Xapian::termcount max_expansion_,
                  int flags_,
                  Query::op combiner_);
 
    bool test_prefix_known(const std::string& candidate) const;
 
    bool test(const std::string& candidate) const {
        return startswith(candidate, prefix) && test_prefix_known(candidate);
    }
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    std::string get_pattern() const { return pattern; }
 
    Xapian::termcount get_max_expansion() const { return max_expansion; }
 
    int get_just_flags() const {
        return flags &~ Xapian::Query::WILDCARD_LIMIT_MASK_;
    }
 
    int get_max_type() const {
        return flags & Xapian::Query::WILDCARD_LIMIT_MASK_;
    }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    termcount get_length() const noexcept XAPIAN_PURE_FUNCTION;
 
    void serialise(std::string & result) const;
 
    QueryWildcard* change_combiner(Xapian::Query::op new_op) {
        if (_refs == 1) {
            combiner = new_op;
            return this;
        }
        return new QueryWildcard(pattern,
                                 max_expansion,
                                 flags,
                                 new_op);
    }
 
    std::string get_fixed_prefix() const { return prefix; }
 
    std::string get_description() const;
};
 
class QueryEditDistance : public Query::Internal {
    std::string pattern;
 
    Xapian::termcount max_expansion;
 
    int flags;
 
    Query::op combiner;
 
    EditDistanceCalculator edcalc;
 
    unsigned edit_distance;
 
    size_t fixed_prefix_len;
 
  public:
    QueryEditDistance(std::string_view pattern_,
                      Xapian::termcount max_expansion_,
                      int flags_,
                      Query::op combiner_,
                      unsigned edit_distance_ = 2,
                      size_t fixed_prefix_len_ = 0)
        : pattern(pattern_),
          max_expansion(max_expansion_),
          flags(flags_),
          combiner(combiner_),
          edcalc(pattern),
          edit_distance(edit_distance_),
          fixed_prefix_len(fixed_prefix_len_) { }
 
    int test(const std::string& candidate) const;
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    std::string get_pattern() const { return pattern; }
 
    size_t get_fixed_prefix_len() const { return fixed_prefix_len; }
 
    Xapian::termcount get_max_expansion() const { return max_expansion; }
 
    int get_just_flags() const {
        return flags &~ Xapian::Query::WILDCARD_LIMIT_MASK_;
    }
 
    int get_max_type() const {
        return flags & Xapian::Query::WILDCARD_LIMIT_MASK_;
    }
 
    unsigned get_threshold() const {
        return edit_distance;
    }
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    termcount get_length() const noexcept XAPIAN_PURE_FUNCTION;
 
    void serialise(std::string & result) const;
 
    QueryEditDistance* change_combiner(Xapian::Query::op new_op) {
        if (_refs == 1) {
            combiner = new_op;
            return this;
        }
        return new QueryEditDistance(pattern,
                                     max_expansion,
                                     flags,
                                     new_op,
                                     edit_distance,
                                     fixed_prefix_len);
    }
 
    std::string get_description() const;
};
 
class QueryInvalid : public Query::Internal {
  public:
    QueryInvalid() { }
 
    Xapian::Query::op get_type() const noexcept XAPIAN_PURE_FUNCTION;
 
    PostListAndEstimate postlist(QueryOptimiser* qopt,
                                 double factor,
                                 TermFreqs* termfreqs) const;
 
    void serialise(std::string & result) const;
 
    std::string get_description() const;
};
 
}
 
}
 
#endif // XAPIAN_INCLUDED_QUERYINTERNAL_H