policy_search_result_builder.hpp

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// -----------------------------------------------------------------------------------------------------
// Copyright (c) 2006-2022, Knut Reinert & Freie Universität Berlin
// Copyright (c) 2016-2022, Knut Reinert & MPI für molekulare Genetik
// This file may be used, modified and/or redistributed under the terms of the 3-clause BSD-License
// shipped with this file and also available at: https://github.com/seqan/seqan3/blob/master/LICENSE.md
// -----------------------------------------------------------------------------------------------------
 
#pragma once
 
#include <seqan3/core/detail/template_inspection.hpp>
#include <seqan3/search/detail/search_traits.hpp>
#include <seqan3/search/fm_index/concept.hpp>
#include <seqan3/search/search_result.hpp>
 
namespace seqan3::detail
{
 
template <typename search_configuration_t>
    requires is_type_specialisation_of_v<search_configuration_t, configuration>
struct policy_search_result_builder
{
protected:
    using search_traits_type = detail::search_traits<search_configuration_t>;
    using search_result_type = typename search_traits_type::search_result_type;
 
    static_assert(!std::same_as<search_result_type, typename search_traits_type::empty_search_result_type>,
                  "The search result type was not configured properly.");
 
    policy_search_result_builder() = default;                                                 
    policy_search_result_builder(policy_search_result_builder &&) = default;                  
    policy_search_result_builder(policy_search_result_builder const &) = default;             
    policy_search_result_builder & operator=(policy_search_result_builder &&) = default;      
    policy_search_result_builder & operator=(policy_search_result_builder const &) = default; 
    ~policy_search_result_builder() = default;                                                
 
    explicit policy_search_result_builder(search_configuration_t const &)
    {}
 
    template <typename index_cursor_t, typename query_index_t, typename callback_t>
    void make_results(std::vector<index_cursor_t> internal_hits, query_index_t idx, callback_t && callback)
    {
        return make_results_impl(std::move(internal_hits), idx, std::forward<callback_t>(callback));
    }
 
    template <typename index_cursor_t, typename query_index_t, typename callback_t>
        requires search_traits_type::output_requires_locate_call && (!search_traits_type::search_single_best_hit)
    void make_results(std::vector<index_cursor_t> internal_hits, query_index_t idx, callback_t && callback)
    {
        std::vector<search_result_type> results{};
        results.reserve(internal_hits.size()); // expect at least as many text positions as cursors, possibly more
 
        make_results_impl(std::move(internal_hits),
                          idx,
                          [&results](auto && search_result)
                          {
                              results.push_back(std::move(search_result));
                          });
 
        // sort by reference id or by reference position if both have the same reference id.
        std::sort(results.begin(),
                  results.end(),
                  [](auto const & r1, auto const & r2)
                  {
                      return (r1.reference_id() == r2.reference_id())
                               ? (r1.reference_begin_position() < r2.reference_begin_position())
                               : (r1.reference_id() < r2.reference_id());
                  });
 
        results.erase(std::unique(results.begin(), results.end()), results.end());
 
        for (auto && search_result : results)
            callback(std::move(search_result));
    }
 
private:
    template <typename index_cursor_t, typename query_index_t, typename callback_t>
    void make_results_impl(std::vector<index_cursor_t> internal_hits,
                           [[maybe_unused]] query_index_t idx,
                           callback_t && callback)
    {
        auto maybe_locate = [](auto const & cursor)
        {
            if constexpr (search_traits_type::output_requires_locate_call)
                return cursor.lazy_locate();
            else
                return std::views::single(std::tuple{0, 0});
        };
 
        for (auto const & cursor : internal_hits)
        {
            for (auto && [ref_id, ref_pos] : maybe_locate(cursor))
            {
                search_result_type result{};
 
                if constexpr (search_traits_type::output_query_id)
                    result.query_id_ = std::move(idx);
                if constexpr (search_traits_type::output_index_cursor)
                    result.cursor_ = cursor;
                if constexpr (search_traits_type::output_reference_id)
                    result.reference_id_ = std::move(ref_id);
                if constexpr (search_traits_type::output_reference_begin_position)
                    result.reference_begin_position_ = std::move(ref_pos);
 
                callback(result);
 
                if constexpr (search_traits_type::search_single_best_hit)
                    return;
            }
        }
    }
};
 
} // namespace seqan3::detail