Increase performance of mass rating changes.

src/library/librarybackend.cpp

@@ -87,6 +87,11 @@ void LibraryBackend::UpdateSongRatingAsync(int id, float rating) {
                              Q_ARG(int, id), Q_ARG(float, rating));
 }
 
+void LibraryBackend::UpdateSongsRatingAsync(const QList<int>& ids, float rating) {
+  metaObject()->invokeMethod(this, "UpdateSongsRating", Qt::QueuedConnection,
+                             Q_ARG(const QList<int>&, ids), Q_ARG(float, rating));
+}
+
 void LibraryBackend::LoadDirectories() {
   DirectoryList dirs = GetAllDirectories();
 
@@ -1105,20 +1110,31 @@ void LibraryBackend::ResetStatistics(int id) {
 void LibraryBackend::UpdateSongRating(int id, float rating) {
   if (id == -1) return;
 
+  QList<int> id_list;
+  id_list << id;
+  UpdateSongsRating(id_list, rating);
+}
+
+void LibraryBackend::UpdateSongsRating(const QList<int> &id_list, float rating) {
+  if (id_list.isEmpty()) return;
+
   QMutexLocker l(db_->Mutex());
   QSqlDatabase db(db_->Connect());
 
+  QStringList id_str_list;
+  for (int i : id_list) {
+    id_str_list << QString::number(i);
+  }
+  QString ids = id_str_list.join(",");
   QSqlQuery q(QString(
-                  "UPDATE %1 SET rating = :rating"
-                  " WHERE ROWID = :id").arg(songs_table_),
-              db);
+                 "UPDATE %1 SET rating = :rating"
+                 " WHERE ROWID IN (%2)").arg(songs_table_, ids),
+               db);
   q.bindValue(":rating", rating);
-  q.bindValue(":id", id);
   q.exec();
   if (db_->CheckErrors(q)) return;
-
-  Song new_song = GetSongById(id, db);
-  emit SongsRatingChanged(SongList() << new_song);
+  SongList new_song_list = GetSongsById(id_str_list, db);
+  emit SongsRatingChanged(new_song_list);
 }
 
 void LibraryBackend::DeleteAll() {

src/library/librarybackend.h

@@ -184,6 +184,7 @@ class LibraryBackend : public LibraryBackendInterface {
   void IncrementSkipCountAsync(int id, float progress);
   void ResetStatisticsAsync(int id);
   void UpdateSongRatingAsync(int id, float rating);
+  void UpdateSongsRatingAsync(const QList<int>& ids, float rating);
 
   void DeleteAll();
 
@@ -206,6 +207,7 @@ class LibraryBackend : public LibraryBackendInterface {
   void IncrementSkipCount(int id, float progress);
   void ResetStatistics(int id);
   void UpdateSongRating(int id, float rating);
+  void UpdateSongsRating(const QList<int>& id_list, float rating);
   void ReloadSettings();
 
 signals:

src/playlist/playlist.cpp

@@ -1814,6 +1814,21 @@ void Playlist::RateSong(const QModelIndex& index, double rating) {
   }
 }
 
+void Playlist::RateSongs(const QModelIndexList& index_list, double rating) {
+  QList<int> id_list;
+  for (const QModelIndex &index : index_list) {
+    int row = index.row();
+
+    if (has_item_at(row)) {
+      PlaylistItemPtr item = item_at(row);
+      if (item && item->IsLocalLibraryItem() && item->Metadata().id() != -1) {
+        id_list << item->Metadata().id();
+      }
+    }
+  }
+  library_->UpdateSongsRatingAsync(id_list, rating);
+}
+
 void Playlist::AddSongInsertVetoListener(SongInsertVetoListener* listener) {
   veto_listeners_.append(listener);
   connect(listener, SIGNAL(destroyed()), this,

src/playlist/playlist.h

@@ -258,6 +258,7 @@ class Playlist : public QAbstractListModel {
 
   // Changes rating of a song to the given value asynchronously
   void RateSong(const QModelIndex& index, double rating);
+  void RateSongs(const QModelIndexList& index_list, double rating);
 
   // Registers an object which will get notifications when new songs
   // are about to be inserted into this playlist.

src/playlist/playlistview.cpp

@@ -786,12 +786,15 @@ void PlaylistView::mousePressEvent(QMouseEvent* event) {
 
     if (selectedIndexes().contains(index)) {
       // Update all the selected items
+      QModelIndexList src_index_list;
       for (const QModelIndex& index : selectedIndexes()) {
         if (index.data(Playlist::Role_CanSetRating).toBool()) {
-          playlist_->RateSong(playlist_->proxy()->mapToSource(index),
-                              new_rating);
+          QModelIndex src_index = playlist_->proxy()->mapToSource(index);
+          src_index_list << src_index;
+          //playlist_->RateSong(src_index, new_rating);
         }
       }
+      playlist_->RateSongs(src_index_list, new_rating);
     } else {
       // Update only this item
       playlist_->RateSong(playlist_->proxy()->mapToSource(index), new_rating);