Album: Cache album artist.

This allows us to fetch the album artist at most once when parsing an
album, instead of one time for each track

src/Album.cpp

@@ -232,10 +232,13 @@ ArtistPtr Album::albumArtist() const
 {
     if ( m_artistId == 0 )
         return nullptr;
-    return Artist::fetch( m_ml, m_artistId );
+    auto lock = m_albumArtist.lock();
+    if ( m_albumArtist.isCached() == false )
+        m_albumArtist = Artist::fetch( m_ml, m_artistId );
+    return m_albumArtist.get();
 }
 
-bool Album::setAlbumArtist( Artist* artist )
+bool Album::setAlbumArtist( std::shared_ptr<Artist> artist )
 {
     if ( m_artistId == artist->id() )
         return true;
@@ -247,10 +250,12 @@ bool Album::setAlbumArtist( Artist* artist )
         return false;
     if ( m_artistId != 0 )
     {
-        auto previousArtist = Artist::fetch( m_ml, m_artistId );
-        previousArtist->updateNbAlbum( -1 );
+        if ( m_albumArtist.isCached() == false )
+            albumArtist();
+        m_albumArtist.get()->updateNbAlbum( -1 );
     }
     m_artistId = artist->id();
+    m_albumArtist = artist;
     artist->updateNbAlbum( 1 );
     static const std::string ftsReq = "UPDATE " + policy::AlbumTable::Name + "Fts SET "
             " artist = ? WHERE rowid = ?";

src/Album.h

@@ -89,7 +89,7 @@ class Album : public IAlbum, public DatabaseHelpers<Album, policy::AlbumTable>
         unsigned int nbTracks() const override;
 
         virtual ArtistPtr albumArtist() const override;
-        bool setAlbumArtist( Artist* artist );
+        bool setAlbumArtist( std::shared_ptr<Artist> artist );
         virtual std::vector<ArtistPtr> artists(bool desc) const override;
         bool addArtist( std::shared_ptr<Artist> artist );
         bool removeArtist( Artist* artist );
@@ -122,6 +122,7 @@ class Album : public IAlbum, public DatabaseHelpers<Album, policy::AlbumTable>
         bool m_isPresent;
 
         mutable Cache<std::vector<MediaPtr>> m_tracks;
+        mutable Cache<std::shared_ptr<Artist>> m_albumArtist;
 
         friend struct policy::AlbumTable;
 };

src/metadata_services/MetadataParser.cpp

@@ -394,7 +394,7 @@ bool MetadataParser::link( Media& media, std::shared_ptr<Album> album,
         // We don't know if the artist was tagged as artist or albumartist, however, we simply add it
         // as the albumartist until proven we were wrong (ie. until one of the next tracks
         // has a different artist)
-        album->setAlbumArtist( albumArtist.get() );
+        album->setAlbumArtist( albumArtist );
         // Always add the album artist as an artist
         album->addArtist( albumArtist );
         if ( artist != nullptr )
@@ -406,7 +406,7 @@ bool MetadataParser::link( Media& media, std::shared_ptr<Album> album,
         {
             // We have more than a single artist on this album, fallback to various artists
             auto variousArtists = Artist::fetch( m_ml, medialibrary::VariousArtistID );
-            album->setAlbumArtist( variousArtists.get() );
+            album->setAlbumArtist( variousArtists );
             // Add those two artists as "featuring".
             album->addArtist( albumArtist );
         }

test/unittest/AlbumTests.cpp

@@ -242,7 +242,7 @@ TEST_F( Albums, AlbumArtist )
     auto album = ml->createAlbum( "test" );
     ASSERT_EQ( album->albumArtist(), nullptr );
     auto artist = ml->createArtist( "artist" );
-    album->setAlbumArtist( artist.get() );
+    album->setAlbumArtist( artist );
     ASSERT_NE( album->albumArtist(), nullptr );
 
     Reload();
@@ -266,7 +266,7 @@ TEST_F( Albums, SearchByArtist )
 {
     auto a = ml->createAlbum( "sea otters" );
     auto artist = ml->createArtist( "pangolins" );
-    a->setAlbumArtist( artist.get() );
+    a->setAlbumArtist( artist );
 
     auto albums = ml->searchAlbums( "pangol" );
     ASSERT_EQ( 1u, albums.size() );
@@ -276,7 +276,7 @@ TEST_F( Albums, SearchNoDuplicate )
 {
     auto a = ml->createAlbum( "sea otters" );
     auto artist = ml->createArtist( "otters" );
-    a->setAlbumArtist( artist.get() );
+    a->setAlbumArtist( artist );
 
     auto albums = ml->searchAlbums( "otters" );
     ASSERT_EQ( 1u, albums.size() );
@@ -310,7 +310,7 @@ TEST_F( Albums, SearchAfterArtistUpdate )
     auto a = ml->createAlbum( "sea otters" );
     auto artist = ml->createArtist( "pangolin of fire" );
     auto artist2 = ml->createArtist( "pangolin of ice" );
-    a->setAlbumArtist( artist.get() );
+    a->setAlbumArtist( artist );
 
     auto albums = ml->searchAlbums( "fire" );
     ASSERT_EQ( 1u, albums.size() );
@@ -318,7 +318,7 @@ TEST_F( Albums, SearchAfterArtistUpdate )
     albums = ml->searchAlbums( "ice" );
     ASSERT_EQ( 0u, albums.size() );
 
-    a->setAlbumArtist( artist2.get() );
+    a->setAlbumArtist( artist2 );
 
     albums = ml->searchAlbums( "fire" );
     ASSERT_EQ( 0u, albums.size() );

test/unittest/ArtistTests.cpp

@@ -98,8 +98,8 @@ TEST_F( Artists, Albums )
     ASSERT_NE( album1, nullptr );
     ASSERT_NE( album2, nullptr );
 
-    album1->setAlbumArtist( artist.get() );
-    album2->setAlbumArtist( artist.get() );
+    album1->setAlbumArtist( artist );
+    album2->setAlbumArtist( artist );
 
     auto albums = artist->albums( medialibrary::SortingCriteria::Default, false );
     ASSERT_EQ( albums.size(), 2u );
@@ -144,7 +144,7 @@ TEST_F( Artists, GetAll )
         auto a = ml->createArtist( std::to_string( i ) );
         auto alb = ml->createAlbum( std::to_string( i ) );
         ASSERT_NE( nullptr, alb );
-        alb->setAlbumArtist( a.get() );
+        alb->setAlbumArtist( a );
         ASSERT_NE( a, nullptr );
     }
     artists = ml->artists( medialibrary::SortingCriteria::Default, false );
@@ -251,9 +251,9 @@ TEST_F( Artists, SortAlbum )
     auto album3 = ml->createAlbum( "album3" );
     album3->setReleaseYear( 2000, false );
 
-    album1->setAlbumArtist( artist.get() );
-    album2->setAlbumArtist( artist.get() );
-    album3->setAlbumArtist( artist.get() );
+    album1->setAlbumArtist( artist );
+    album2->setAlbumArtist( artist );
+    album3->setAlbumArtist( artist );
 
     // Default order is by descending year, discriminated by lexical order
     auto albums = artist->albums( medialibrary::SortingCriteria::Default, false );
@@ -286,10 +286,10 @@ TEST_F( Artists, Sort )
     // Keep in mind that artists are only listed when they are marked as album artist at least once
     auto a1 = ml->createArtist( "A" );
     auto alb1 = ml->createAlbum( "albumA" );
-    alb1->setAlbumArtist( a1.get() );
+    alb1->setAlbumArtist( a1 );
     auto a2 = ml->createArtist( "B" );
     auto alb2 = ml->createAlbum( "albumB" );
-    alb2->setAlbumArtist( a2.get() );
+    alb2->setAlbumArtist( a2 );
 
     auto artists = ml->artists( medialibrary::SortingCriteria::Alpha, false );
     ASSERT_EQ( 2u, artists.size() );

test/unittest/DeviceTests.cpp

@@ -257,7 +257,7 @@ TEST_F( DeviceFs, RemoveAlbum )
         auto media = ml->media( mock::FileSystemFactory::Root + "audio.mp3" );
         album->addTrack( std::static_pointer_cast<Media>( media ), 1, 1 );
         auto artist = ml->createArtist( "artist" );
-        album->setAlbumArtist( artist.get() );
+        album->setAlbumArtist( artist );
     }
     // And an album that will disappear, along with its artist
     {
@@ -267,7 +267,7 @@ TEST_F( DeviceFs, RemoveAlbum )
         album->addTrack( std::static_pointer_cast<Media>( media ), 1, 1 );
         album->addTrack( std::static_pointer_cast<Media>( media ), 2, 1 );
         auto artist = ml->createArtist( "artist 2" );
-        album->setAlbumArtist( artist.get() );
+        album->setAlbumArtist( artist );
     }
 
     auto albums = ml->albums( medialibrary::SortingCriteria::Default, false );
@@ -302,7 +302,7 @@ TEST_F( DeviceFs, PartialAlbumRemoval )
         album->addTrack( std::static_pointer_cast<Media>( media ), 1, 1 );
         album->addTrack( std::static_pointer_cast<Media>( media2 ), 2, 1 );
         auto newArtist = ml->createArtist( "artist" );
-        album->setAlbumArtist( newArtist.get() );
+        album->setAlbumArtist( newArtist );
         newArtist->addMedia( static_cast<Media&>( *media ) );
         newArtist->addMedia( static_cast<Media&>( *media2 ) );
     }