Do not attempt extra data fetch when hitting the end of a query

src/libs/database/impl/Track.cpp

@@ -343,6 +343,14 @@ namespace lms::db
         utils::execQuery(query, params.range, func);
     }
 
+  void Track::find(Session& session, const FindParameters& params, bool& moreResults, std::function<void(const Track::pointer&)> func)
+    {
+        session.checkReadTransaction();
+
+        auto query{ createQuery<Wt::Dbo::ptr<Track>>(session, params)};
+        utils::execQuery(query, params.range, moreResults, func);
+    }
+
     RangeResults<TrackId> Track::findSimilarTrackIds(Session& session, const std::vector<TrackId>& tracks, std::optional<Range> range)
     {
         assert(!tracks.empty());

src/libs/database/impl/TrackList.cpp

@@ -142,25 +142,21 @@ namespace lms::db
         TrackListEntry::pointer res;
 
         auto entries = getEntries(Range{ pos, 1 });
-        if (!entries.empty())
-            res = entries.front();
+        if (!entries.results.empty())
+            res = entries.results.front();
 
         return res;
     }
 
-    std::vector<TrackListEntry::pointer> TrackList::getEntries(std::optional<Range> range) const
+    RangeResults<ObjectPtr<TrackListEntry>> TrackList::getEntries(std::optional<Range> range) const
     {
         assert(session());
 
-        auto entries{
-            session()->find<TrackListEntry>()
+        auto query{session()->find<TrackListEntry>()
             .where("tracklist_id = ?").bind(getId())
-            .orderBy("id")
-            .limit(range ? static_cast<int>(range->size) + 1 : -1)
-            .offset(range ? static_cast<int>(range->offset) : -1)
-            .resultList() };
+            .orderBy("id") };
 
-        return std::vector<TrackListEntry::pointer>(entries.begin(), entries.end());
+        return utils::execQuery<TrackListEntry::pointer>(query, range);
     }
 
     TrackListEntry::pointer TrackList::getEntryByTrackAndDateTime(ObjectPtr<Track> track, const Wt::WDateTime& dateTime) const
@@ -237,17 +233,6 @@ namespace lms::db
         return res;
     }
 
-    bool TrackList::hasTrack(TrackId trackId) const
-    {
-        assert(session());
-
-        Wt::Dbo::collection<TrackListEntry::pointer> res = session()->query<TrackListEntry::pointer>("SELECT p_e from tracklist_entry p_e INNER JOIN tracklist p ON p_e.tracklist_id = p.id")
-            .where("p_e.track_id = ?").bind(trackId)
-            .where("p.id = ?").bind(getId());
-
-        return res.size() > 0;
-    }
-
     std::vector<Track::pointer> TrackList::getSimilarTracks(std::optional<std::size_t> offset, std::optional<std::size_t> size) const
     {
         assert(session());

src/libs/database/impl/Utils.hpp

@@ -56,15 +56,20 @@ namespace lms::db::utils
         {
             res.range.offset = range->offset;
             applyRange(query, Range{ range->offset, range->size + 1 });
+
+            res.results.reserve(range->size);
         }
 
         auto collection{ query.resultList() };
-        res.results.assign(collection.begin(), collection.end());
-        if (range && res.results.size() == static_cast<std::size_t>(range->size) + 1)
+        for (auto itResult{ collection.begin() }; itResult != collection.end(); ++itResult)
+        {
+            if (range && res.results.size() == range->size)
             {
-            // TODO may optim by not actually requesting the last one
                 res.moreResults = true;
-            res.results.pop_back();
+                break;
+            }
+
+            res.results.push_back(std::move(*itResult));
         }
 
         res.range.size = res.results.size();
@@ -85,6 +90,28 @@ namespace lms::db::utils
         }
     }
 
+    template <typename ResultType, typename Query>
+    void execQuery(Query& query, std::optional<Range> range, bool& moreResults, std::function<void(const ResultType&)> func)
+    {
+        if (range)
+            applyRange(query, Range{ range->offset, range->size + 1 });
+
+        moreResults = false;
+
+        std::size_t count{};
+        for (const auto& res : query.resultList())
+        {
+            if (range && (count++ == static_cast<std::size_t>(range->size)))
+            {
+                moreResults = true;
+                break;
+            }
+
+            LMS_SCOPED_TRACE_DETAILED("Database", "ExecQueryResult");
+            func(res);
+        }
+    }
+
     Wt::WDateTime normalizeDateTime(const Wt::WDateTime& dateTime);
 }
 

src/libs/database/include/database/Track.hpp

@@ -118,6 +118,7 @@ namespace lms::db
         static RangeResults<TrackId>	findIds(Session& session, const FindParameters& parameters);
         static RangeResults<pointer>	find(Session& session, const FindParameters& parameters);
         static void						find(Session& session, const FindParameters& parameters, std::function<void(const Track::pointer&)> func);
+        static void						find(Session& session, const FindParameters& parameters, bool& moreResults, std::function<void(const Track::pointer&)> func);
         static RangeResults<PathResult>	findPaths(Session& session, std::optional<Range> range = std::nullopt);
         static RangeResults<TrackId>	findIdsTrackMBIDDuplicates(Session& session, std::optional<Range> range = std::nullopt);
         static RangeResults<TrackId>	findIdsWithRecordingMBIDAndMissingFeatures(Session& session, std::optional<Range> range = std::nullopt);

src/libs/database/include/database/TrackList.hpp

@@ -85,7 +85,7 @@ namespace lms::db
         bool										isEmpty() const;
         std::size_t									getCount() const;
         ObjectPtr<TrackListEntry>					getEntry(std::size_t pos) const;
-        std::vector<ObjectPtr<TrackListEntry>>		getEntries(std::optional<Range> range = {}) const;
+        RangeResults<ObjectPtr<TrackListEntry>>		getEntries(std::optional<Range> range = {}) const;
         ObjectPtr<TrackListEntry>					getEntryByTrackAndDateTime(ObjectPtr<Track> track, const Wt::WDateTime& dateTime) const;
 
         std::vector<TrackId>						getTrackIds() const;
@@ -97,8 +97,6 @@ namespace lms::db
         std::vector<ObjectPtr<Cluster>> getClusters() const;
         std::vector<std::vector<ObjectPtr<Cluster>>> getClusterGroups(const std::vector<ClusterTypeId>& clusterTypeIds, std::size_t size) const;
 
-        bool hasTrack(TrackId trackId) const;
-
         // Ordered from most clusters in common
         std::vector<ObjectPtr<Track>> getSimilarTracks(std::optional<std::size_t> offset = {}, std::optional<std::size_t> size = {}) const;
 

src/libs/database/test/TrackList.cpp

@@ -198,8 +198,8 @@ namespace lms::db::tests
         {
             auto transaction{ session.createReadTransaction() };
             auto entries{ trackList.get()->getEntries() };
-            ASSERT_EQ(entries.size(), 1);
-            EXPECT_EQ(entries.front()->getTrack()->getId(), track1.getId());
+            ASSERT_EQ(entries.results.size(), 1);
+            EXPECT_EQ(entries.results.front()->getTrack()->getId(), track1.getId());
         }
 
         {
@@ -210,16 +210,16 @@ namespace lms::db::tests
         {
             auto transaction{ session.createReadTransaction() };
             auto entries{ trackList.get()->getEntries() };
-            ASSERT_EQ(entries.size(), 2);
-            EXPECT_EQ(entries[0]->getTrack()->getId(), track1.getId());
-            EXPECT_EQ(entries[1]->getTrack()->getId(), track2.getId());
+            ASSERT_EQ(entries.results.size(), 2);
+            EXPECT_EQ(entries.results[0]->getTrack()->getId(), track1.getId());
+            EXPECT_EQ(entries.results[1]->getTrack()->getId(), track2.getId());
         }
 
         {
             auto transaction{ session.createReadTransaction() };
             auto entries{ trackList.get()->getEntries(Range {1, 1}) };
-            ASSERT_EQ(entries.size(), 1);
-            EXPECT_EQ(entries[0]->getTrack()->getId(), track2.getId());
+            ASSERT_EQ(entries.results.size(), 1);
+            EXPECT_EQ(entries.results[0]->getTrack()->getId(), track2.getId());
         }
     }
 }

src/libs/subsonic/impl/entrypoints/Playlists.cpp

@@ -72,7 +72,7 @@ namespace lms::api::subsonic
         Response::Node playlistNode{ createPlaylistNode(tracklist, context.dbSession) };
 
         auto entries{ tracklist->getEntries() };
-        for (const TrackListEntry::pointer& entry : entries)
+        for (const TrackListEntry::pointer& entry : entries.results)
             playlistNode.addArrayChild("entry", createSongNode(context, entry->getTrack(), user));
 
         response.addNode("playlist", std::move(playlistNode));
@@ -129,7 +129,7 @@ namespace lms::api::subsonic
         Response::Node playlistNode{ createPlaylistNode(tracklist, context.dbSession) };
 
         auto entries{ tracklist->getEntries() };
-        for (const TrackListEntry::pointer& entry : entries)
+        for (const TrackListEntry::pointer& entry : entries.results)
             playlistNode.addArrayChild("entry", createSongNode(context, entry->getTrack(), user));
 
         response.addNode("playlist", std::move(playlistNode));

src/lms/ui/PlayQueue.cpp

@@ -148,10 +148,11 @@ namespace lms::ui
         shuffleBtn->clicked().connect([this]
             {
                 {
+                    // TODO write scope could be reduced
                     auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                     db::TrackList::pointer queue{ getQueue() };
-                    auto entries{ queue->getEntries() };
+                    auto entries{ queue->getEntries().results };
                     core::random::shuffleContainer(entries);
 
                     queue.modify()->clear();
@@ -430,9 +431,9 @@ namespace lms::ui
         auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
         db::TrackList::pointer queue{ getQueue() };
-        std::vector<db::TrackListEntry::pointer> entries{ queue->getEntries(db::Range {_trackPos ? *_trackPos + 1 : 0, getCapacity()}) };
-        tracks.reserve(entries.size());
-        for (db::TrackListEntry::pointer entry : entries)
+        auto entries{ queue->getEntries(db::Range {_trackPos ? *_trackPos + 1 : 0, getCapacity()}) };
+        tracks.reserve(entries.results.size());
+        for (db::TrackListEntry::pointer& entry : entries.results)
         {
             tracks.push_back(entry->getTrack()->getId());
             entry.remove();
@@ -492,9 +493,11 @@ namespace lms::ui
         auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const db::TrackList::pointer queue{ getQueue() };
-        const auto tracklistEntries{ queue->getEntries(db::Range {_entriesContainer->getCount(), _batchSize}) };
-        for (const db::TrackListEntry::pointer& tracklistEntry : tracklistEntries)
+        const auto entries{ queue->getEntries(db::Range {_entriesContainer->getCount(), _batchSize}) };
+        for (const db::TrackListEntry::pointer& tracklistEntry : entries.results)
             addEntry(tracklistEntry);
+
+        _entriesContainer->setHasMore(entries.moreResults);
     }
 
     void PlayQueue::addEntry(const db::TrackListEntry::pointer& tracklistEntry)

src/lms/ui/common/InfiniteScrollingContainer.cpp

@@ -32,39 +32,33 @@ namespace lms::ui
         reset();
     }
 
-	void
-	InfiniteScrollingContainer::clear()
+    void InfiniteScrollingContainer::clear()
     {
         assert(false);
     }
 
-	void
-	InfiniteScrollingContainer::reset()
+    void InfiniteScrollingContainer::reset()
     {
         _elements->clear();
         setHasMore(true);
     }
 
-	std::size_t
-	InfiniteScrollingContainer::getCount()
+    std::size_t InfiniteScrollingContainer::getCount()
     {
         return _elements->count();
     }
 
-	void
-	InfiniteScrollingContainer::add(std::unique_ptr<Wt::WWidget> result)
+    void InfiniteScrollingContainer::add(std::unique_ptr<Wt::WWidget> result)
     {
         return _elements->addWidget(std::move(result));
     }
 
-	void
-	InfiniteScrollingContainer::setHasMore()
+    void InfiniteScrollingContainer::setHasMore()
     {
         setHasMore(true);
     }
 
-	void
-	InfiniteScrollingContainer::setHasMore(bool hasMore)
+    void InfiniteScrollingContainer::setHasMore(bool hasMore)
     {
         if (hasMore)
             displayLoadingIndicator();
@@ -72,21 +66,19 @@ namespace lms::ui
             hideLoadingIndicator();
     }
 
-	void
-	InfiniteScrollingContainer::remove(Wt::WWidget& widget)
+    void InfiniteScrollingContainer::remove(Wt::WWidget& widget)
     {
         _elements->removeWidget(&widget);
     }
 
-	void
-	InfiniteScrollingContainer::remove(std::size_t first, std::size_t last)
+    void InfiniteScrollingContainer::remove(std::size_t first, std::size_t last)
     {
         assert(last >= first);
         assert(last < static_cast<std::size_t>(_elements->count()));
 
         // remove from end as API is quite uneffective (minimize moves)
         std::size_t i{ last };
-		while (Wt::WWidget* widget {_elements->widget(i)})
+        while (Wt::WWidget * widget{ _elements->widget(static_cast<int>(i)) })
         {
             _elements->removeWidget(widget);
             if (i-- == first)
@@ -94,21 +86,18 @@ namespace lms::ui
         }
     }
 
-	Wt::WWidget*
-	InfiniteScrollingContainer::getWidget(std::size_t pos) const
+    Wt::WWidget* InfiniteScrollingContainer::getWidget(std::size_t pos) const
     {
-		return _elements->widget(pos);
+        return _elements->widget(static_cast<int>(pos));
     }
 
-	std::optional<std::size_t>
-	InfiniteScrollingContainer::getIndexOf(Wt::WWidget& widget) const
+    std::optional<std::size_t> InfiniteScrollingContainer::getIndexOf(Wt::WWidget& widget) const
     {
         return _elements->indexOf(&widget);
     }
 
 
-	void
-	InfiniteScrollingContainer::displayLoadingIndicator()
+    void InfiniteScrollingContainer::displayLoadingIndicator()
     {
         _loadingIndicator = bindWidget<Wt::WTemplate>("loading-indicator", createLoadingIndicator());
         _loadingIndicator->scrollVisibilityChanged().connect([this](bool visible)
@@ -116,17 +105,13 @@ namespace lms::ui
                 if (!visible)
                     return;
 
-			const auto previousCount {_elements->count()};
                 onRequestElements.emit();
-			setHasMore(previousCount != _elements->count());
             });
     }
 
-	void
-	InfiniteScrollingContainer::hideLoadingIndicator()
+    void InfiniteScrollingContainer::hideLoadingIndicator()
     {
         _loadingIndicator = nullptr;
         bindEmpty("loading-indicator");
     }
-
 }

src/lms/ui/common/InfiniteScrollingContainer.hpp

@@ -57,11 +57,12 @@ namespace lms::ui
 
 			Wt::Signal<>	onRequestElements;
 
+			void setHasMore(bool hasMore); // can be used to add elements afterwards
+
 		private:
 			void clear() override;
 			void displayLoadingIndicator();
 			void hideLoadingIndicator();
-			void setHasMore(bool hasMore); // can be used to add elements afterwards
 
 			Wt::WContainerWidget*	_elements;
 			Wt::WTemplate*			_loadingIndicator;

src/lms/ui/common/LoadingIndicator.cpp

@@ -21,8 +21,7 @@
 
 namespace lms::ui
 {
-	std::unique_ptr<Wt::WTemplate>
-	createLoadingIndicator()
+    std::unique_ptr<Wt::WTemplate> createLoadingIndicator()
     {
         auto res {std::make_unique<Wt::WTemplate>(Wt::WString::tr("Lms.LoadingIndicator.template"))};
 

src/lms/ui/explore/ArtistView.cpp

@@ -332,12 +332,13 @@ namespace lms::ui
                 releaseContainer.container->add(releaseListHelpers::createEntryForArtist(release, artist));
             }
         }
+
+        releaseContainer.container->setHasMore(false);
     }
 
     bool Artist::addSomeNonReleaseTracks()
     {
         bool areTracksAdded{};
-        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Range range{ static_cast<std::size_t>(_trackContainer->getCount()), _tracksBatchSize };
 
@@ -348,6 +349,8 @@ namespace lms::ui
         params.setSortMethod(TrackSortMethod::Name);
         params.setNonRelease(true);
 
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
+
         const auto tracks{ Track::find(LmsApp->getDbSession(), params) };
         for (const Track::pointer& track : tracks.results)
         {
@@ -360,6 +363,8 @@ namespace lms::ui
             areTracksAdded = true;
         }
 
+        _trackContainer->setHasMore(tracks.moreResults);
+
         return areTracksAdded;
     }
 

src/lms/ui/explore/ArtistsView.cpp

@@ -125,6 +125,8 @@ namespace lms::ui
                     _container->add(ArtistListHelpers::createEntry(artist));
             }
         }
+
+        _container->setHasMore(artistIds.moreResults);
     }
 
 } // namespace lms::ui

src/lms/ui/explore/ReleaseView.cpp

@@ -463,7 +463,7 @@ namespace lms::ui
                     auto isStarred{ [=] { return core::Service<feedback::IFeedbackService>::get()->isStarred(LmsApp->getUserId(), trackId); } };
 
                     Wt::WPushButton* starBtn{ entry->bindNew<Wt::WPushButton>("star", Wt::WString::tr(isStarred() ? "Lms.Explore.unstar" : "Lms.Explore.star")) };
-                    starBtn->clicked().connect([=, this]
+                    starBtn->clicked().connect([=]
                         {
                             if (isStarred())
                             {

src/lms/ui/explore/ReleasesView.cpp

@@ -129,6 +129,8 @@ namespace lms::ui
                     _container->add(releaseListHelpers::createEntry(release));
             }
         }
+
+        _container->setHasMore(releaseIds.moreResults);
     }
 
     std::vector<ReleaseId> Releases::getAllReleases()

src/lms/ui/explore/SearchView.cpp

@@ -159,6 +159,8 @@ namespace lms::ui
                     _artists->add(ArtistListHelpers::createEntry(artist));
             }
         }
+
+        _artists->setHasMore(artistIds.moreResults);
     }
 
     void SearchView::addSomeReleases()
@@ -177,6 +179,8 @@ namespace lms::ui
                     _releases->add(releaseListHelpers::createEntry(release));
             }
         }
+
+        _releases->setHasMore(releaseIds.moreResults);
     }
 
     void SearchView::addSomeTracks()
@@ -196,5 +200,7 @@ namespace lms::ui
                     _tracks->add(TrackListHelpers::createEntry(track, _playQueueController, _filters));
             }
         }
+
+        _tracks->setHasMore(trackIds.moreResults);
     }
 }

src/lms/ui/explore/TrackListView.cpp

@@ -188,10 +188,13 @@ namespace lms::ui
         params.setSortMethod(db::TrackSortMethod::TrackList);
         params.setRange(db::Range{ static_cast<std::size_t>(_container->getCount()), _batchSize });
         
-        db::Track::find(LmsApp->getDbSession(), params, [this](const Track::pointer& track)
+        bool moreResults{};
+        db::Track::find(LmsApp->getDbSession(), params, moreResults, [this](const Track::pointer& track)
             {
                 _container->add(TrackListHelpers::createEntry(track, _playQueueController, _filters));
             });
+            
+        _container->setHasMore(moreResults);
     }
 } // namespace lms::ui
 

src/lms/ui/explore/TrackListsView.cpp

@@ -121,6 +121,8 @@ namespace lms::ui
             if (const TrackList::pointer trackList{ TrackList::find(LmsApp->getDbSession(), trackListId) })
                 addTracklist(trackList);
         }
+
+        _container->setHasMore(trackListIds.moreResults);
     }
 
     void TrackLists::addTracklist(const ObjectPtr<TrackList>& trackList)

src/lms/ui/explore/TracksView.cpp

@@ -128,6 +128,8 @@ namespace lms::ui
             if (const Track::pointer track{ Track::find(LmsApp->getDbSession(), trackId) })
                 _container->add(TrackListHelpers::createEntry(track, _playQueueController, _filters));
         }
+
+        _container->setHasMore(trackIds.moreResults);
     }
 
     std::vector<db::TrackId> Tracks::getAllTracks()