Media: Store the number of playlist a media is present in

This can be used to avoid full table scans when knowing if a media is
present in a playlist or not

src/Media.cpp

@@ -77,7 +77,8 @@ Media::Media( MediaLibraryPtr ml, sqlite::Row& row )
         >> m_title
         >> m_filename
         >> m_isFavorite
-        >> m_isPresent;
+        >> m_isPresent
+        >> m_nbPlaylists;
 }
 
 Media::Media( MediaLibraryPtr ml, const std::string& title, Type type )
@@ -97,6 +98,7 @@ Media::Media( MediaLibraryPtr ml, const std::string& title, Type type )
     , m_filename( title )
     , m_isFavorite( false )
     , m_isPresent( true )
+    , m_nbPlaylists( 0 )
     , m_metadata( m_ml, IMetadata::EntityType::Media )
     , m_changed( false )
 {
@@ -310,6 +312,17 @@ unsigned int Media::releaseDate() const
     return m_releaseDate;
 }
 
+uint32_t Media::nbPlaylists() const
+{
+    return m_nbPlaylists.load( std::memory_order_relaxed );
+}
+
+void Media::udpateNbPlaylist(int32_t increment) const
+{
+    // Only update the cached representation, let the triggers handle the DB values
+    m_nbPlaylists.fetch_add( increment, std::memory_order_relaxed );
+}
+
 const IMetadata& Media::metadata( IMedia::MetadataType type ) const
 {
     using MDType = typename std::underlying_type<IMedia::MetadataType>::type;
@@ -559,7 +572,7 @@ void Media::createTable( sqlite::Connection* connection )
         sqlite::Tools::executeRequest( connection, req );
 }
 
-void Media::createTriggers( sqlite::Connection* connection )
+void Media::createTriggers( sqlite::Connection* connection, uint32_t modelVersion )
 {
     const std::string reqs[] = {
         #include "database/tables/Media_triggers_v14.sql"
@@ -567,6 +580,27 @@ void Media::createTriggers( sqlite::Connection* connection )
 
     for ( const auto& req : reqs )
         sqlite::Tools::executeRequest( connection, req );
+
+    if ( modelVersion >= 14 )
+    {
+        sqlite::Tools::executeRequest( connection,
+            "CREATE TRIGGER IF NOT EXISTS increment_media_nb_playlist AFTER INSERT ON "
+            " PlaylistMediaRelation "
+            " BEGIN "
+                " UPDATE " + policy::MediaTable::Name + " SET nb_playlists = nb_playlists + 1 "
+                    " WHERE id_media = new.media_id;"
+            " END;"
+        );
+
+        sqlite::Tools::executeRequest( connection,
+            "CREATE TRIGGER IF NOT EXISTS decrement_media_nb_playlist AFTER DELETE ON "
+            " PlaylistMediaRelation "
+            " BEGIN "
+                " UPDATE " + policy::MediaTable::Name + " SET nb_playlists = nb_playlists - 1 "
+                    " WHERE id_media = old.media_id;"
+            " END;"
+        );
+    }
 }
 
 bool Media::addLabel( LabelPtr label )

src/Media.h

@@ -66,7 +66,7 @@ class Media : public IMedia, public DatabaseHelpers<Media, policy::MediaTable>
 
         static std::shared_ptr<Media> create( MediaLibraryPtr ml, Type type, const std::string& fileName );
         static void createTable( sqlite::Connection* connection );
-        static void createTriggers( sqlite::Connection* connection );
+        static void createTriggers( sqlite::Connection* connection, uint32_t modelVersion );
 
         virtual int64_t id() const override;
         virtual Type type() const override;
@@ -113,6 +113,8 @@ class Media : public IMedia, public DatabaseHelpers<Media, policy::MediaTable>
         bool setThumbnail( const std::string& thumbnail, Thumbnail::Origin origin );
         virtual unsigned int insertionDate() const override;
         virtual unsigned int releaseDate() const override;
+        uint32_t nbPlaylists() const;
+        void udpateNbPlaylist( int32_t increment ) const;
 
         virtual const IMetadata& metadata( MetadataType type ) const override;
         virtual bool setMetadata( MetadataType type, const std::string& value ) override;
@@ -172,6 +174,7 @@ private:
         std::string m_filename;
         bool m_isFavorite;
         bool m_isPresent;
+        mutable std::atomic_uint32_t m_nbPlaylists;
 
         // Auto fetched related properties
         mutable Cache<AlbumTrackPtr> m_albumTrack;

src/MediaLibrary.cpp

@@ -178,7 +178,7 @@ void MediaLibrary::createAllTriggers()
     Album::createTriggers( m_dbConnection.get() );
     AlbumTrack::createTriggers( m_dbConnection.get() );
     Artist::createTriggers( m_dbConnection.get(), dbModelVersion );
-    Media::createTriggers( m_dbConnection.get() );
+    Media::createTriggers( m_dbConnection.get(), dbModelVersion );
     File::createTriggers( m_dbConnection.get() );
     Genre::createTriggers( m_dbConnection.get() );
     Playlist::createTriggers( m_dbConnection.get() );
@@ -1012,7 +1012,7 @@ void MediaLibrary::migrateModel3to5()
     for ( const auto& req : reqs )
         sqlite::Tools::executeRequest( getConn(), req );
     // Re-create triggers removed in the process
-    Media::createTriggers( getConn() );
+    Media::createTriggers( getConn(), 5 );
     Playlist::createTriggers( getConn() );
     t->commit();
 }
@@ -1041,7 +1041,7 @@ void MediaLibrary::migrateModel7to8()
         sqlite::Tools::executeRequest( getConn(), req );
     // Re-create triggers removed in the process
     Artist::createTriggers( getConn(), 8u );
-    Media::createTriggers( getConn() );
+    Media::createTriggers( getConn(), 5 );
     File::createTriggers( getConn() );
     t->commit();
 }
@@ -1167,7 +1167,7 @@ void MediaLibrary::migrateModel13to14()
     Show::createTable( dbConn );
     VideoTrack::createTable( dbConn );
     // Re-create triggers removed in the process
-    Media::createTriggers( dbConn );
+    Media::createTriggers( dbConn, 14 );
     AlbumTrack::createTriggers( dbConn );
     Album::createTriggers( dbConn );
     Artist::createTriggers( dbConn, 14 );

src/Playlist.cpp

@@ -192,9 +192,12 @@ bool Playlist::add( const IMedia& media, unsigned int position )
             LOG_ERROR( "Can't add a media without any files to a playlist" );
             return false;
         }
-        return sqlite::Tools::executeInsert( m_ml->getConn(), req, media.id(),
+        if ( sqlite::Tools::executeInsert( m_ml->getConn(), req, media.id(),
                                              (*mainFile)->mrl(), m_id,
-                                             sqlite::ForeignKey{ position } );
+                                             sqlite::ForeignKey{ position } ) == false )
+            return false;
+        static_cast<const Media&>( media ).udpateNbPlaylist( 1 );
+        return true;
     }
     catch (const sqlite::errors::ConstraintViolation& ex)
     {
@@ -257,7 +260,10 @@ bool Playlist::remove( const IMedia& media )
 {
     static const std::string req = "DELETE FROM PlaylistMediaRelation WHERE "
             "playlist_id = ? AND media_id = ?";
-    return sqlite::Tools::executeDelete( m_ml->getConn(), req, m_id, media.id() );
+    if ( sqlite::Tools::executeDelete( m_ml->getConn(), req, m_id, media.id() ) == false )
+        return false;
+    static_cast<const Media&>( media ).udpateNbPlaylist( -1 );
+    return true;
 }
 
 void Playlist::createTable( sqlite::Connection* dbConn, uint32_t dbModel )

src/database/migrations/migration13-14.sql

@@ -51,6 +51,12 @@ std::to_string( static_cast<typename std::underlying_type<IMedia::Type>::type>(
 "type = " + std::to_string( static_cast<typename std::underlying_type<IMedia::Type>::type>(
 IMedia::Type::Unknown ) ),
 
+/******************* Populate new media.nb_playlists **************************/
+
+"UPDATE " + MediaTable::Name + " SET nb_playlists = "
+"(SELECT COUNT(media_id) FROM PlaylistMediaRelation WHERE media_id = id_media )"
+"WHERE id_media IN (SELECT media_id FROM PlaylistMediaRelation)",
+
 /******************* Migrate metadata table ***********************************/
 "CREATE TEMPORARY TABLE " + MetadataTable::Name + "_backup"
 "("

src/database/tables/Media_v14.sql

@@ -16,6 +16,7 @@
     "filename TEXT,"
     "is_favorite BOOLEAN NOT NULL DEFAULT 0,"
     "is_present BOOLEAN NOT NULL DEFAULT 1,"
+    "nb_playlists UNSIGNED INTEGER NOT NULL DEFAULT 0,"
 
     "FOREIGN KEY(thumbnail_id) REFERENCES " + policy::ThumbnailTable::Name
     + "(id_thumbnail)"

test/unittest/MediaTests.cpp

@@ -750,6 +750,46 @@ TEST_F( Medias, VacuumOldExternal )
     ASSERT_EQ( nullptr, s1 );
 }
 
+TEST_F( Medias, NbPlaylists )
+{
+    auto m = std::static_pointer_cast<Media>( ml->addExternalMedia( "media.mkv" ) );
+    ASSERT_EQ( 0u, m->nbPlaylists() );
+
+    auto playlist = ml->createPlaylist( "playlisẗ" );
+    auto res = playlist->append( *m );
+    ASSERT_TRUE( res );
+    ASSERT_EQ( 1u, m->nbPlaylists() );
+
+    Reload();
+
+    m = ml->media( m->id() );
+    ASSERT_EQ( 1u, m->nbPlaylists() );
+
+    playlist = ml->playlist( playlist->id() );
+    playlist->remove( m->id() );
+    ASSERT_EQ( 0u, m->nbPlaylists() );
+
+    Reload();
+
+    m = ml->media( m->id() );
+    ASSERT_EQ( 0u, m->nbPlaylists() );
+
+    playlist = ml->playlist( playlist->id() );
+    playlist->append( *m );
+    ASSERT_EQ( 1u, m->nbPlaylists() );
+
+    Reload();
+
+    m = ml->media( m->id() );
+    ASSERT_EQ( 1u, m->nbPlaylists() );
+
+    ml->deletePlaylist( playlist->id() );
+
+    Reload();
+    m = ml->media( m->id() );
+    ASSERT_EQ( 0u, m->nbPlaylists() );
+}
+
 class FetchMedia : public Tests
 {
 protected:

test/unittest/MiscTests.cpp

@@ -174,7 +174,7 @@ TEST_F( DbModel, Upgrade12to13 )
     // We can't check for the number of albums anymore since they are deleted
     // as part of 13 -> 14 migration
 
-    CheckNbTriggers( 32 );
+    CheckNbTriggers( 34 );
 }
 
 TEST_F( DbModel, Upgrade13to14 )
@@ -202,14 +202,19 @@ TEST_F( DbModel, Upgrade13to14 )
     auto playlistMedia = playlists[0]->media()->all();
     ASSERT_EQ( 3u, playlistMedia.size() );
     ASSERT_EQ( media[0]->id(), playlistMedia[0]->id() );
+    ASSERT_EQ( 1u, std::static_pointer_cast<Media>( playlistMedia[0] )->nbPlaylists() );
     ASSERT_EQ( media[1]->id(), playlistMedia[1]->id() );
+    ASSERT_EQ( 1u, std::static_pointer_cast<Media>( playlistMedia[1] )->nbPlaylists() );
     ASSERT_EQ( media[2]->id(), playlistMedia[2]->id() );
+    ASSERT_EQ( 1u, std::static_pointer_cast<Media>( playlistMedia[2] )->nbPlaylists() );
 
     ASSERT_EQ( IMedia::Type::External, media[2]->type() );
 
     auto externalMedia = ml->media( 99 );
     ASSERT_NE( nullptr, externalMedia );
     ASSERT_EQ( IMedia::Type::Unknown, externalMedia->type() );
+    ASSERT_EQ( 0u, std::static_pointer_cast<Media>( externalMedia )->nbPlaylists() );
 
-    CheckNbTriggers( 32 );
+
+    CheckNbTriggers( 34 );
 }