Updated the Service interface

src/Makefile.am

@@ -20,7 +20,6 @@ lms_SOURCES = \
 	$(srcdir)/database/User.cpp				\
 	$(srcdir)/image/Image.cpp				\
 	$(srcdir)/main/main.cpp					\
-	$(srcdir)/main/Services.cpp				\
 	$(srcdir)/metadata/AvFormat.cpp				\
 	$(srcdir)/metadata/TagLibParser.cpp			\
 	$(srcdir)/scanner/MediaScanner.cpp			\

src/api/subsonic/SubsonicResource.cpp

@@ -32,7 +32,7 @@
 #include "database/Release.hpp"
 #include "database/Track.hpp"
 #include "database/TrackList.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "similarity/SimilaritySearcher.hpp"
 #include "utils/Logger.hpp"
 #include "utils/Utils.hpp"
@@ -880,7 +880,7 @@ Response handleGetArtistInfoRequestCommon(RequestContext& context, bool id3)
 	if (!artist->getMBID().empty())
 		artistInfoNode.createChild("musicBrainzId").setValue(artist->getMBID());
 
-	auto similarArtistsId {getServices().similaritySearcher->getSimilarArtists(context.db.getSession(), artist.id(), count)};
+	auto similarArtistsId {getService<Similarity::Searcher>()->getSimilarArtists(context.db.getSession(), artist.id(), count)};
 	for ( const auto& similarArtistId : similarArtistsId )
 	{
 		Database::Artist::pointer similarArtist {Database::Artist::getById(context.db.getSession(), similarArtistId)};
@@ -1059,7 +1059,7 @@ handleGetSimilarSongsRequestCommon(RequestContext& context, bool id3)
 	// "Returns a random collection of songs from the given artist and similar artists"
 	auto tracks {artist->getRandomTracks(count / 2)};
 
-	auto similarArtistsId {getServices().similaritySearcher->getSimilarArtists(context.db.getSession(), artist.id(), 5)};
+	auto similarArtistsId {getService<Similarity::Searcher>()->getSimilarArtists(context.db.getSession(), artist.id(), 5)};
 	for ( const auto& similarArtistId : similarArtistsId )
 	{
 		Database::Artist::pointer similarArtist {Database::Artist::getById(context.db.getSession(), similarArtistId)};
@@ -1433,10 +1433,10 @@ handleGetCoverArt(RequestContext& context, Wt::Http::ResponseContinuation* conti
 	switch (id.type)
 	{
 		case Id::Type::Track:
-			cover = getServices().coverArtGrabber->getFromTrack(context.db.getSession(), id.value, Image::Format::JPEG, size);
+			cover = getService<CoverArt::Grabber>()->getFromTrack(context.db.getSession(), id.value, Image::Format::JPEG, size);
 			break;
 		case Id::Type::Release:
-			cover = getServices().coverArtGrabber->getFromRelease(context.db.getSession(), id.value, Image::Format::JPEG, size);
+			cover = getService<CoverArt::Grabber>()->getFromRelease(context.db.getSession(), id.value, Image::Format::JPEG, size);
 			break;
 		default:
 			throw Error {Error::CustomType::BadId};

src/main/Service.hpp

@@ -19,26 +19,36 @@
 
 #include <memory>
 
-namespace CoverArt
+template <typename T>
+class ServiceProvider
 {
-	class Grabber;
+	public:
-}
 
-namespace Scanner {
+		template <class ...Args>
-	class MediaScanner;
+		static
-}
+		T&
+		create(Args&&... args)
+		{
+			assign(std::make_unique<T>(std::forward<Args>(args)...));
+			return *get();
+		}
+		static void assign(std::unique_ptr<T> service) { _service = std::move(service); }
+		static void clear() { _service.reset(); }
 
-namespace Similarity {
+		static T* get() { return _service.get(); }
-	class Searcher;
-}
 
-
+	private:
-struct Services
+		static std::unique_ptr<T> _service;
-{
-	std::unique_ptr<CoverArt::Grabber>	coverArtGrabber;
-	std::unique_ptr<Scanner::MediaScanner>	mediaScanner;
-	std::unique_ptr<Similarity::Searcher>	similaritySearcher;
 };
 
-Services& getServices();
+template <typename T>
+std::unique_ptr<T> ServiceProvider<T>::_service = {};
+
+template <typename T>
+T*
+getService()
+{
+	return ServiceProvider<T>::get();
+}
+
 

src/main/Services.cpp

@@ -1,31 +0,0 @@
-/*
- * Copyright (C) 2019 Emeric Poupon
- *
- * This file is part of LMS.
- *
- * LMS 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 3 of the License, or
- * (at your option) any later version.
- *
- * LMS 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 LMS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include "Services.hpp"
-
-#include "cover/CoverArtGrabber.hpp"
-#include "scanner/MediaScanner.hpp"
-#include "similarity/SimilaritySearcher.hpp"
-
-Services& getServices()
-{
-	static Services services;
-	return services;
-}
-

src/main/main.cpp

@@ -34,7 +34,7 @@
 #include "ui/LmsApplication.hpp"
 #include "utils/Config.hpp"
 #include "utils/Logger.hpp"
-#include "Services.hpp"
+#include "Service.hpp"
 
 std::vector<std::string> generateWtConfig(std::string execPath)
 {
@@ -127,15 +127,16 @@ int main(int argc, char* argv[])
 		UserInterface::LmsApplicationGroupContainer appGroups;
 
 		// Service initialization order is important
-		getServices().mediaScanner = std::make_unique<Scanner::MediaScanner>(*connectionPool);
+		Scanner::MediaScanner& mediaScanner {ServiceProvider<Scanner::MediaScanner>::create(*connectionPool)};
 
 		Similarity::FeaturesScannerAddon similarityFeaturesScannerAddon(*connectionPool);
 
-		getServices().mediaScanner->setAddon(similarityFeaturesScannerAddon);
+		mediaScanner.setAddon(similarityFeaturesScannerAddon);
-		getServices().coverArtGrabber = std::make_unique<CoverArt::Grabber>();
-		getServices().coverArtGrabber->setDefaultCover(server.appRoot() + "/images/unknown-cover.jpg");
 
-		getServices().similaritySearcher = std::make_unique<Similarity::Searcher>(similarityFeaturesScannerAddon);
+		CoverArt::Grabber& coverArtGrabber {ServiceProvider<CoverArt::Grabber>::create()};
+		coverArtGrabber.setDefaultCover(server.appRoot() + "/images/unknown-cover.jpg");
+
+		ServiceProvider<Similarity::Searcher>::create(similarityFeaturesScannerAddon);
 
 		API::Subsonic::SubsonicResource subsonicResource {*connectionPool};
 
@@ -153,7 +154,7 @@ int main(int argc, char* argv[])
 
 		// Start
 		LMS_LOG(MAIN, INFO) << "Starting media scanner...";
-		getServices().mediaScanner->start();
+		mediaScanner.start();
 
 		LMS_LOG(MAIN, INFO) << "Starting server...";
 		server.start();
@@ -167,7 +168,7 @@ int main(int argc, char* argv[])
 		server.stop();
 
 		LMS_LOG(MAIN, INFO) << "Stopping media scanner...";
-		getServices().mediaScanner->stop();
+		mediaScanner.stop();
 
 		LMS_LOG(MAIN, INFO) << "Clean stop!";
 		res = EXIT_SUCCESS;

src/ui/LmsApplication.cpp

@@ -36,7 +36,7 @@
 #include "database/Cluster.hpp"
 #include "database/Release.hpp"
 #include "explore/Explore.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "utils/Logger.hpp"
 #include "utils/Utils.hpp"
 
@@ -459,7 +459,7 @@ LmsApplication::createHome()
 
 	// Events from MediaScanner
 	std::string sessionId = LmsApp->sessionId();
-	getServices().mediaScanner->scanComplete().connect([=] (Scanner::MediaScanner::Stats stats)
+	getService<Scanner::MediaScanner>()->scanComplete().connect([=] (Scanner::MediaScanner::Stats stats)
 	{
 		// Runs from media scanner context
 		Wt::WServer::instance()->post(sessionId, [=]

src/ui/PlayQueueView.cpp

@@ -22,7 +22,7 @@
 #include <Wt/WText.h>
 
 #include "database/TrackList.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "similarity/SimilaritySearcher.hpp"
 #include "utils/Logger.hpp"
 #include "LmsApplication.hpp"
@@ -399,7 +399,7 @@ PlayQueue::addRadioTrack()
 	if (trackIds.empty())
 		return;
 
-	auto res = getServices().similaritySearcher->getSimilarTracks(LmsApp->getDboSession(), std::set<Database::IdType>(trackIds.begin(), trackIds.end()), 1);
+	auto res = getService<Similarity::Searcher>()->getSimilarTracks(LmsApp->getDboSession(), std::set<Database::IdType>(trackIds.begin(), trackIds.end()), 1);
 	for (auto trackId : res)
 	{
 		auto trackToAdd = Database::Track::getById(LmsApp->getDboSession(), trackId);

src/ui/admin/DatabaseSettingsView.cpp

@@ -28,7 +28,7 @@
 #include <Wt/WTemplateFormView.h>
 
 #include "database/Cluster.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "utils/Logger.hpp"
 #include "utils/Utils.hpp"
 
@@ -288,7 +288,7 @@ DatabaseSettingsView::refreshView()
 		{
 			model->saveData();
 
-			getServices().mediaScanner->reschedule();
+			getService<Scanner::MediaScanner>()->reschedule();
 			LmsApp->notifyMsg(MsgType::Success, Wt::WString::tr("Lms.Admin.Database.settings-saved"));
 		}
 
@@ -305,7 +305,7 @@ DatabaseSettingsView::refreshView()
 
 	immScanBtn->clicked().connect([=] ()
 	{
-		getServices().mediaScanner->scheduleImmediateScan();
+		getService<Scanner::MediaScanner>()->scheduleImmediateScan();
 		LmsApp->notifyMsg(MsgType::Info, Wt::WString::tr("Lms.Admin.Database.scan-launched"));
 	});
 

src/ui/explore/ArtistInfoView.cpp

@@ -20,7 +20,7 @@
 #include "ArtistInfoView.hpp"
 
 #include "database/Artist.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "similarity/SimilaritySearcher.hpp"
 #include "utils/Utils.hpp"
 
@@ -63,7 +63,7 @@ ArtistInfo::refresh()
 	if (!artistId)
 		return;
 
-	auto artistsIds = getServices().similaritySearcher->getSimilarArtists(LmsApp->getDboSession(), *artistId, 5);
+	auto artistsIds = getService<Similarity::Searcher>()->getSimilarArtists(LmsApp->getDboSession(), *artistId, 5);
 
 	Wt::Dbo::Transaction transaction(LmsApp->getDboSession());
 

src/ui/explore/ReleaseInfoView.cpp

@@ -22,7 +22,7 @@
 #include <Wt/WAnchor.h>
 
 #include "database/Release.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "similarity/SimilaritySearcher.hpp"
 #include "utils/Utils.hpp"
 
@@ -68,7 +68,7 @@ ReleaseInfo::refresh()
 	if (!releaseId)
 		return;
 
-	std::vector<Database::IdType> releasesIds {getServices().similaritySearcher->getSimilarReleases(LmsApp->getDboSession(), *releaseId, 5)};
+	std::vector<Database::IdType> releasesIds {getService<Similarity::Searcher>()->getSimilarReleases(LmsApp->getDboSession(), *releaseId, 5)};
 
 	Wt::Dbo::Transaction transaction {LmsApp->getDboSession()};
 

src/ui/resource/ImageResource.cpp

@@ -24,7 +24,7 @@
 
 #include "cover/CoverArtGrabber.hpp"
 #include "database/Track.hpp"
-#include "main/Services.hpp"
+#include "main/Service.hpp"
 #include "utils/Exception.hpp"
 #include "utils/Logger.hpp"
 #include "utils/Utils.hpp"
@@ -80,7 +80,7 @@ ImageResource::handleRequest(const Wt::Http::Request& request, Wt::Http::Respons
 		// transactions are not thread safe
 		{
 			Wt::WApplication::UpdateLock lock(LmsApp);
-			cover = getServices().coverArtGrabber->getFromTrack(LmsApp->getDboSession(), *trackId, Image::Format::JPEG, *size);
+			cover = getService<CoverArt::Grabber>()->getFromTrack(LmsApp->getDboSession(), *trackId, Image::Format::JPEG, *size);
 		}
 	}
 	else if (releaseIdStr)
@@ -92,7 +92,7 @@ ImageResource::handleRequest(const Wt::Http::Request& request, Wt::Http::Respons
 		// transactions are not thread safe
 		{
 			Wt::WApplication::UpdateLock lock(LmsApp);
-			cover = getServices().coverArtGrabber->getFromRelease(LmsApp->getDboSession(), *releaseId, Image::Format::JPEG, *size);
+			cover = getService<CoverArt::Grabber>()->getFromRelease(LmsApp->getDboSession(), *releaseId, Image::Format::JPEG, *size);
 		}
 	}
 	else