[gnome-music/wip/mschraal/playlists-fixes: 5/7] coremodel: Splice playlist model on changes

[Jean Felder <jfelder src gnome org>]

commit b4e6396f7dd01ae82b45de22958ca10e291c1773
Author: Marinus Schraal <mschraal gnome org>
Date:   Sat Feb 22 16:23:24 2020 +0100

    coremodel: Splice playlist model on changes
    
    When reacting to the items-changed signal on the current playlist model,
    all items were removed & added one at a time. This would result in
    changes possibly stopping the playing playlist, as the playlist could
    effectively could become empty.
    
    Instead make the signal handler smarter and splice the changes in
    one go.

 gnomemusic/coremodel.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/gnomemusic/coremodel.py b/gnomemusic/coremodel.py
index 17eb5167..2b5d7c12 100644
--- a/gnomemusic/coremodel.py
+++ b/gnomemusic/coremodel.py
@@ -232,10 +232,7 @@ class CoreModel(GObject.GObject):
             return
 
         def _on_items_changed(model, position, removed, added):
-            if removed > 0:
-                for i in list(range(removed)):
-                    self._playlist_model.remove(position)
-
+            songs_list = []
             if added > 0:
                 for i in list(range(added)):
                     coresong = model[position + i]
@@ -253,6 +250,10 @@ class CoreModel(GObject.GObject):
                         GObject.BindingFlags.BIDIRECTIONAL
                         | GObject.BindingFlags.SYNC_CREATE)
 
+                    songs_list.append(song)
+
+            self._playlist_model.splice(position, removed, songs_list)
+
         played_states = [SongWidget.State.PLAYING, SongWidget.State.PLAYED]
         for song in self._playlist_model:
             if song.props.state in played_states: