Don't ever restructure or reset the library model when statistics on a song are changed.

src/library/librarybackend.cpp

@@ -810,8 +810,6 @@ void LibraryBackend::IncrementPlayCount(int id) {
   QMutexLocker l(db_->Mutex());
   QSqlDatabase db(db_->Connect());
 
-  Song old_song = GetSongById(id, db);
-
   QSqlQuery q(QString("UPDATE %1 SET playcount = playcount + 1,"
                       "              lastplayed = :now"
                       " WHERE ROWID = :id").arg(songs_table_), db);
@@ -822,9 +820,7 @@ void LibraryBackend::IncrementPlayCount(int id) {
     return;
 
   Song new_song = GetSongById(id, db);
-
-  emit SongsDeleted(SongList() << old_song);
-  emit SongsDiscovered(SongList() << new_song);
+  emit SongsStatisticsChanged(SongList() << new_song);
 }
 
 void LibraryBackend::IncrementSkipCount(int id) {
@@ -834,8 +830,6 @@ void LibraryBackend::IncrementSkipCount(int id) {
   QMutexLocker l(db_->Mutex());
   QSqlDatabase db(db_->Connect());
 
-  Song old_song = GetSongById(id, db);
-
   QSqlQuery q(QString("UPDATE %1 SET skipcount = skipcount + 1"
                       " WHERE ROWID = :id").arg(songs_table_), db);
   q.bindValue(":id", id);
@@ -844,7 +838,5 @@ void LibraryBackend::IncrementSkipCount(int id) {
     return;
 
   Song new_song = GetSongById(id, db);
-
-  emit SongsDeleted(SongList() << old_song);
-  emit SongsDiscovered(SongList() << new_song);
+  emit SongsStatisticsChanged(SongList() << new_song);
 }

src/library/librarybackend.h

@@ -154,6 +154,7 @@ class LibraryBackend : public LibraryBackendInterface {
 
   void SongsDiscovered(const SongList& songs);
   void SongsDeleted(const SongList& songs);
+  void SongsStatisticsChanged(const SongList& songs);
 
   void TotalSongCountUpdated(int total);
 

src/library/librarymodel.cpp

@@ -52,6 +52,7 @@ LibraryModel::~LibraryModel() {
 void LibraryModel::Init() {
   connect(backend_, SIGNAL(SongsDiscovered(SongList)), SLOT(SongsDiscovered(SongList)));
   connect(backend_, SIGNAL(SongsDeleted(SongList)), SLOT(SongsDeleted(SongList)));
+  connect(backend_, SIGNAL(SongsStatisticsChanged(SongList)), SLOT(SongsStatisticsChanged(SongList)));
   connect(backend_, SIGNAL(TotalSongCountUpdated(int)), SIGNAL(TotalSongCountUpdated(int)));
 
   backend_->UpdateTotalSongCountAsync();
@@ -131,6 +132,17 @@ void LibraryModel::SongsDiscovered(const SongList& songs) {
   }
 }
 
+void LibraryModel::SongsStatisticsChanged(const SongList& songs) {
+  // This is called if there was a minor change to the songs that will not
+  // normally require the library to be restructured.  We can just update our
+  // internal cache of Song objects without worrying about resetting the model.
+  foreach (const Song& song, songs) {
+    if (song_nodes_.contains(song.id())) {
+      song_nodes_[song.id()]->metadata = song;
+    }
+  }
+}
+
 LibraryItem* LibraryModel::CreateCompilationArtistNode(bool signal, LibraryItem* parent) {
   if (signal)
     beginInsertRows(ItemToIndex(parent), parent->children.count(), parent->children.count());

src/library/librarymodel.h

@@ -117,6 +117,7 @@ class LibraryModel : public SimpleTreeModel<LibraryItem> {
   // From LibraryBackend
   void SongsDiscovered(const SongList& songs);
   void SongsDeleted(const SongList& songs);
+  void SongsStatisticsChanged(const SongList& songs);
   void Reset();
 
  private:

src/playlist/playlistmanager.cpp

@@ -52,6 +52,7 @@ void PlaylistManager::Init(LibraryBackend* library_backend,
   sequence_ = sequence;
 
   connect(library_backend_, SIGNAL(SongsDiscovered(SongList)), SLOT(SongsDiscovered(SongList)));
+  connect(library_backend_, SIGNAL(SongsStatisticsChanged(SongList)), SLOT(SongsDiscovered(SongList)));
 
   foreach (const PlaylistBackend::Playlist& p, playlist_backend->GetAllPlaylists()) {
     AddPlaylist(p.id, p.name);