[gnome-music/wip/mschraal/tracker-changed-signal: 2/4] grltrackerwrapper: Batch updates

[Marinus Schraal <mschraal src gnome org>]

commit 9a4d49cf1911b55145b599fb684b1373ff76b024
Author: Marinus Schraal <mschraal gnome org>
Date:   Tue Jul 16 15:53:04 2019 +0200

    grltrackerwrapper: Batch updates
    
    Grilo Tracker source's 'content-changed' signals come in mostly as single
    changes. This is very heavy on Music as it has to check if it has any impact
    on the artist and albums model.
    
    Batch the changed medias, so the artist and albums change check can be done
    just once for a change set. This keeps the UI more responsive.

 gnomemusic/grilowrappers/grltrackerwrapper.py | 53 ++++++++++++++++++---------
 1 file changed, 36 insertions(+), 17 deletions(-)
---
diff --git a/gnomemusic/grilowrappers/grltrackerwrapper.py b/gnomemusic/grilowrappers/grltrackerwrapper.py
index f439b67a..1f114437 100644
--- a/gnomemusic/grilowrappers/grltrackerwrapper.py
+++ b/gnomemusic/grilowrappers/grltrackerwrapper.py
@@ -87,6 +87,8 @@ class GrlTrackerWrapper(GObject.GObject):
         self._song_search_proxy = self._coremodel.props.songs_search_proxy
         self._album_search_model = self._coremodel.props.albums_search
         self._artist_search_model = self._coremodel.props.artists_search
+        self._batch_changed_medias = {}
+        self._content_changed_timeout = None
 
         self._song_search_tracker = Gfm.FilterListModel.new(self._model)
         self._song_search_tracker.set_filter_func(lambda a: False)
@@ -104,7 +106,7 @@ class GrlTrackerWrapper(GObject.GObject):
             source, coremodel, coreselection, grilo)
 
         self._source.notify_change_start()
-        self._source.connect("content-changed", self._on_content_changed)
+        self._source.connect("content-changed", self._batch_content_changed)
 
     @GObject.Property(
         type=Grl.Source, default=None, flags=GObject.ParamFlags.READABLE)
@@ -132,22 +134,39 @@ class GrlTrackerWrapper(GObject.GObject):
 
         return query
 
-    def _on_content_changed(self, source, medias, change_type, loc_unknown):
-        for media in medias:
-            # The Tracker indexed paths may differ from Music's paths.
-            # In that case Tracker will report it as 'changed', while
-            # it means 'added' to Music.
-            if (change_type == Grl.SourceChangeType.CHANGED
-                    or change_type == Grl.SourceChangeType.ADDED):
-                print("ADDED/CHANGED", media.get_id())
-                self._changed_media(media)
-                self._check_album_change(media)
-                self._check_artist_change(media)
-            elif change_type == Grl.SourceChangeType.REMOVED:
-                print("REMOVED", media.get_id())
-                self._remove_media(media)
-                self._check_album_change(media)
-                self._check_artist_change(media)
+    def _batch_content_changed(self, source, medias, change_type, loc_unknown):
+        if medias == []:
+            return
+
+        if change_type not in self._batch_changed_medias.keys():
+            self._batch_changed_medias[change_type] = []
+
+        [self._batch_changed_medias[change_type].append(media)
+            for media in medias]
+
+        if self._content_changed_timeout is None:
+            self._content_changed_timeout = GLib.timeout_add(
+                250, self._on_content_changed)
+
+    def _on_content_changed(self):
+        for change_type in self._batch_changed_medias.keys():
+            for media in self._batch_changed_medias[change_type]:
+                # The Tracker indexed paths may differ from Music's paths.
+                # In that case Tracker will report it as 'changed', while
+                # it means 'added' to Music.
+                if (change_type == Grl.SourceChangeType.CHANGED
+                        or change_type == Grl.SourceChangeType.ADDED):
+                    print("ADDED/CHANGED", media.get_id())
+                    self._changed_media(media)
+                elif change_type == Grl.SourceChangeType.REMOVED:
+                    print("REMOVED", media.get_id())
+                    self._remove_media(media)
+
+        self._check_album_change(media)
+        self._check_artist_change(media)
+
+        self._batch_changed_medias = {}
+        self._content_changed_timeout = None
 
     def _check_album_change(self, media):
         album_ids = {}