Only include real playlists to the playlist model

There are for example folder markers in the playlists returned by libspotify.
We should only take into account those whose type is SP_PLAYLIST_TYPE_PLAYLIST.

Also fixes the playlist model population: the indexes weren't handled quite
correctly, they were confused with the starred tracks list.

Fixed the PlaylistModel::insertRows(). It now works as intended by Qt.
Removed needless members from PlaylistModel::Entry and added a constructor.

mainwindow.cpp

@@ -875,18 +875,32 @@ void MainWindow::fillPlaylistModel()
         m_pc = sp_session_playlistcontainer(m_session);
         sp_playlistcontainer_add_callbacks(m_pc, &SpotifyPlaylistContainer::spotifyCallbacks, this);
     }
-    const int numPlaylists = sp_playlistcontainer_num_playlists(m_pc);
+
+    int numPlaylists = sp_playlistcontainer_num_playlists(m_pc);
+
+    // Collect the playlists that are of type "playlist", discard others
+    QList<sp_playlist*> playLists;
+    playLists.reserve(numPlaylists);
+    for (int i = 0; i < numPlaylists; ++i) {
+        if (sp_playlistcontainer_playlist_type(m_pc, i) == SP_PLAYLIST_TYPE_PLAYLIST) {
+            playLists.append(sp_playlistcontainer_playlist(m_pc, i));
+        }
+    }
+    numPlaylists = 1 + playLists.count();  // 1 place needed for the starred tracks list
+
     m_playlistModel->removeRows(0, m_playlistModel->rowCount());
     m_playlistModel->insertRows(0, numPlaylists);
+
     int currRow = -1;
 
     // Add the special playlist for starred tracks
     {
         sp_playlist *pl = sp_session_starred_create(m_session);
         Q_ASSERT(pl);
         if (pl == m_currentPlaylist) {
-            currRow = numPlaylists;
+            currRow = 0;
         }
+
         sp_playlist_add_callbacks(pl, &SpotifyPlaylists::spotifyCallbacks, NULL);
         const QModelIndex &index = m_playlistModel->index(0);
         m_playlistModel->setData(index, QChar(0x2605) + i18n("Starred tracks"));
@@ -896,7 +910,7 @@ void MainWindow::fillPlaylistModel()
     static QList<sp_playlist*> playlistsWithCallbacksSet;
 
     for (int i = 1; i < numPlaylists; ++i) {
-        sp_playlist *pl = sp_playlistcontainer_playlist(m_pc, i);
+        sp_playlist *pl = playLists.at(i - 1);
         if (pl == m_currentPlaylist) {
             currRow = i;
         }

playlistmodel.cpp

@@ -34,12 +34,13 @@ PlaylistModel::~PlaylistModel()
 
 bool PlaylistModel::insertRows(int row, int count, const QModelIndex &parent)
 {
-    if (row < 0 || row > m_playLists.count() || count <= 0) {
+    if (row < 0 || count <= 0) {
         return false;
     }
     beginInsertRows(parent, row, row + count - 1);
+    m_playLists.reserve(m_playLists.count() + count);
     for (int i = row; i < row + count; ++i) {
-        m_playLists << Entry();
+        m_playLists.insert(i, Entry());
     }
     endInsertRows();
     return true;

playlistmodel.h

@@ -45,9 +45,11 @@ class PlaylistModel
 
 private:
     struct Entry {
+        Entry() :
+            m_playlist(0)
+        {}
+
         QString      m_title;
-        QString      m_owner;
-        bool         m_collaborative;
         sp_playlist *m_playlist;
     };
     QList<Entry> m_playLists;