SubsonicAPI: optimized search for tracks
This commit is contained in:
emeric
@@ -30,89 +30,86 @@
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namespace Recommendation
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{
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using namespace Database;
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using namespace Database;
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std::unique_ptr<IPlaylistGeneratorService>
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createPlaylistGeneratorService(Db& db, Recommendation::IRecommendationService& recommendationService)
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{
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return std::make_unique<PlaylistGeneratorService>(db, recommendationService);
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}
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std::unique_ptr<IPlaylistGeneratorService> createPlaylistGeneratorService(Db& db, Recommendation::IRecommendationService& recommendationService)
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{
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return std::make_unique<PlaylistGeneratorService>(db, recommendationService);
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}
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PlaylistGeneratorService::PlaylistGeneratorService(Db& db, Recommendation::IRecommendationService& recommendationService)
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: _db {db}
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, _recommendationService {recommendationService}
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{
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_constraints.push_back(std::make_unique<PlaylistGeneratorConstraint::ConsecutiveArtists>(_db));
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_constraints.push_back(std::make_unique<PlaylistGeneratorConstraint::ConsecutiveReleases>(_db));
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_constraints.push_back(std::make_unique<PlaylistGeneratorConstraint::DuplicateTracks>());
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}
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PlaylistGeneratorService::PlaylistGeneratorService(Db& db, Recommendation::IRecommendationService& recommendationService)
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: _db{ db }
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, _recommendationService{ recommendationService }
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{
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_constraints.push_back(std::make_unique<PlaylistGeneratorConstraint::ConsecutiveArtists>(_db));
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_constraints.push_back(std::make_unique<PlaylistGeneratorConstraint::ConsecutiveReleases>(_db));
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_constraints.push_back(std::make_unique<PlaylistGeneratorConstraint::DuplicateTracks>());
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}
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std::vector<TrackId>
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PlaylistGeneratorService::extendPlaylist(TrackListId tracklistId, std::size_t maxCount) const
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{
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LMS_LOG(RECOMMENDATION, DEBUG) << "Requested to extend playlist by " << maxCount << " similar tracks";
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std::vector<TrackId> PlaylistGeneratorService::extendPlaylist(TrackListId tracklistId, std::size_t maxCount) const
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{
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LMS_LOG(RECOMMENDATION, DEBUG) << "Requested to extend playlist by " << maxCount << " similar tracks";
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// supposed to be ordered from most similar to least similar
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std::vector<TrackId> similarTracks {_recommendationService.findSimilarTracks(tracklistId, maxCount * 2)}; // ask for more tracks than we need as it will be easier to respect constraints
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// supposed to be ordered from most similar to least similar
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std::vector<TrackId> similarTracks{ _recommendationService.findSimilarTracks(tracklistId, maxCount * 2) }; // ask for more tracks than we need as it will be easier to respect constraints
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const std::vector<TrackId> startingTracks {getTracksFromTrackList(tracklistId)};
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const std::vector<TrackId> startingTracks{ getTracksFromTrackList(tracklistId) };
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std::vector<TrackId> finalResult = startingTracks;
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finalResult.reserve(startingTracks.size() + maxCount);
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std::vector<TrackId> finalResult = startingTracks;
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finalResult.reserve(startingTracks.size() + maxCount);
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std::vector<float> scores;
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for (std::size_t i {}; i < maxCount; ++i)
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{
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if (similarTracks.empty())
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break;
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std::vector<float> scores;
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for (std::size_t i{}; i < maxCount; ++i)
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{
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if (similarTracks.empty())
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break;
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scores.resize(similarTracks.size(), {});
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scores.resize(similarTracks.size(), {});
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// select the similar track that has the best score
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for (std::size_t trackIndex {}; trackIndex < similarTracks.size(); ++trackIndex)
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{
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using namespace Database::Debug;
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// select the similar track that has the best score
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for (std::size_t trackIndex{}; trackIndex < similarTracks.size(); ++trackIndex)
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{
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using namespace Database::Debug;
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finalResult.push_back(similarTracks[trackIndex]);
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finalResult.push_back(similarTracks[trackIndex]);
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scores[trackIndex] = 0;
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for (const auto& constraint : _constraints)
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scores[trackIndex] += constraint->computeScore(finalResult, finalResult.size() - 1);
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scores[trackIndex] = 0;
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for (const auto& constraint : _constraints)
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scores[trackIndex] += constraint->computeScore(finalResult, finalResult.size() - 1);
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finalResult.pop_back();
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finalResult.pop_back();
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// early exit if we consider we found a track with no constraint violation (since similarTracks sorted from most to least similar)
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if (scores[trackIndex] < 0.01)
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break;
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}
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// early exit if we consider we found a track with no constraint violation (since similarTracks sorted from most to least similar)
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if (scores[trackIndex] < 0.01)
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break;
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}
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// get the best score
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const std::size_t bestScoreIndex {static_cast<std::size_t>(std::distance(std::cbegin(scores), std::min_element(std::cbegin(scores), std::cend(scores))))};
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// get the best score
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const std::size_t bestScoreIndex{ static_cast<std::size_t>(std::distance(std::cbegin(scores), std::min_element(std::cbegin(scores), std::cend(scores)))) };
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finalResult.push_back(similarTracks[bestScoreIndex]);
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similarTracks.erase(std::begin(similarTracks) + bestScoreIndex);
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}
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finalResult.push_back(similarTracks[bestScoreIndex]);
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similarTracks.erase(std::begin(similarTracks) + bestScoreIndex);
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}
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// for now, just get some more similar tracks
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return std::vector(std::cbegin(finalResult) + startingTracks.size(), std::cend(finalResult));
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}
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// for now, just get some more similar tracks
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return std::vector(std::cbegin(finalResult) + startingTracks.size(), std::cend(finalResult));
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}
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TrackContainer
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PlaylistGeneratorService::getTracksFromTrackList(Database::TrackListId tracklistId) const
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{
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TrackContainer tracks;
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TrackContainer PlaylistGeneratorService::getTracksFromTrackList(Database::TrackListId tracklistId) const
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{
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TrackContainer tracks;
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Session& dbSession {_db.getTLSSession()};
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auto transaction {dbSession.createSharedTransaction()};
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Session& dbSession{ _db.getTLSSession() };
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auto transaction{ dbSession.createSharedTransaction() };
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Track::FindParameters params;
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params.setTrackList(tracklistId);
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params.setSortMethod(TrackSortMethod::TrackList);
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params.setDistinct(false);
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Track::FindParameters params;
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params.setTrackList(tracklistId);
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params.setSortMethod(TrackSortMethod::TrackList);
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params.setDistinct(false);
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for (const TrackId trackId : Track::find(dbSession, params).results)
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tracks.push_back(trackId);
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for (const TrackId trackId : Track::findIds(dbSession, params).results)
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tracks.push_back(trackId);
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return tracks;
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}
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return tracks;
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}
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}
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