[Rhythmbox-devel] "Shuffle Playlist" feature

[Ryan Hughes <ryan iheartryan com>]

Hi.  I'm trying to create a "shuffle playlist" feature.  The problem I've 
been having is that the only way to shuffle is to use the "Shuffle" 
feature, where you can't see what's coming up and you can't see what's 
just been played.  I want to just shuffle the playlist and then play 
straight through.

Well:  I've got it to the point where you can right-click on a playlist 
and click shuffle.  The songs in the playlist are then shuffled and will 
play in their new order.  Everything is perfect, right?

The problem is, if you then QUIT rhythmbox and then open it back up again, 
you'll find that the playlist is back to its original order, not in the 
new shuffled order.

Is there some sort of "commit playlist" function that I need to call?  I 
couldn't find anything like that.  I noticed that 
rb_query_model_move_entry calls a function called ..._emit_reorder.  Also, 
rb_static_playlist_source_move_entry marks the playlist dirty.

What else do I need to do in order to get the new playlist order written 
back to the db?

Thanks.  I've included a patch against rhythmbox 0.11.2.  Hopefully, this 
feature will be considered for inclusion in future releases (that is, once 
it's done).

--Ryan

Index: shell/rb-playlist-manager.c
===================================================================
--- shell/rb-playlist-manager.c	(revision 4)
+++ shell/rb-playlist-manager.c	(working copy)
@@ -82,6 +82,8 @@
 							     RBPlaylistManager *mgr);
 static void rb_playlist_manager_cmd_queue_playlist (GtkAction *action,
 						    RBPlaylistManager *mgr);
+static void rb_playlist_manager_cmd_shuffle_playlist (GtkAction *action,
+						    RBPlaylistManager *mgr);
 
 struct RBPlaylistManagerPrivate
 {
@@ -154,6 +156,9 @@
 	{ "QueuePlaylist", NULL, N_("_Queue All Tracks"), NULL,
 	  N_("Add all tracks in this playlist to the queue"),
 	  G_CALLBACK (rb_playlist_manager_cmd_queue_playlist) },
+	{ "ShufflePlaylist", NULL, N_("_Shuffle Playlist"), NULL,
+	  N_("Shuffle the tracks in this playlist"),
+	  G_CALLBACK (rb_playlist_manager_cmd_shuffle_playlist) },
 };
 static guint rb_playlist_manager_n_actions = G_N_ELEMENTS (rb_playlist_manager_actions);
 
@@ -1241,7 +1246,77 @@
 	g_object_unref (model);
 }
 
+
+static gboolean
+_count_track_cb (RhythmDBQueryModel *model,
+		 GtkTreePath *path,
+		 GtkTreeIter *iter,
+		 GList **retval)
+{
+	RhythmDBEntry *entry;
+
+	entry = rhythmdb_query_model_iter_to_entry (model, iter);
+  *retval = g_list_append(*retval, entry);
+
+	return FALSE;
+}
+
 static void
+_shuffle_track_cb (gpointer data,
+		 gpointer user_data)
+{
+  RhythmDBEntry *entry;
+  GList *passdata;
+
+  RBStaticPlaylistSource *playlist_source;
+  int numtracks;
+  int new_location;
+
+  entry = (RhythmDBEntry *)data;
+  passdata = (GList *)passdata;
+
+  playlist_source = (RBStaticPlaylistSource *)g_list_nth_data(passdata, 0);
+  numtracks = *(int *)(g_list_nth_data(passdata, 1));
+
+  new_location = g_random_int_range(0, numtracks);
+
+  rb_static_playlist_source_move_entry (playlist_source, entry, new_location);
+	rhythmdb_entry_unref (entry);
+}
+
+static void
+rb_playlist_manager_cmd_shuffle_playlist (GtkAction *action,
+					RBPlaylistManager *mgr)
+{
+	RhythmDBQueryModel *model;
+  int numtracks = 0;
+  GList *passdata;
+  GList *entries;
+
+	g_object_get (mgr->priv->selected_source, "query-model", &model, NULL);
+
+  // Phase I:  Put the tracks into a list, so I can traverse while I move.
+  entries = NULL;
+	gtk_tree_model_foreach (GTK_TREE_MODEL (model),
+				(GtkTreeModelForeachFunc) _count_track_cb,
+				&entries);
+
+  numtracks = g_list_length(entries);
+
+  // Phase II:  Traverse the list, placing the entries in random places in the
+  // playlist.
+  passdata = NULL;
+  passdata = g_list_append(passdata, mgr->priv->selected_source);
+  passdata = g_list_append(passdata, &numtracks);
+
+  g_list_foreach(entries, _shuffle_track_cb, passdata);
+
+  g_list_free (entries);
+  g_list_free (passdata);
+	g_object_unref (model);
+}
+
+static void
 rb_playlist_manager_cmd_rename_playlist (GtkAction *action,
 					 RBPlaylistManager *mgr)
 {
Index: data/ui/rhythmbox-ui.xml
===================================================================
--- data/ui/rhythmbox-ui.xml	(revision 4)
+++ data/ui/rhythmbox-ui.xml	(working copy)
@@ -221,6 +221,9 @@
     <menuitem name="RenameAutoPlaylistPopup" action="MusicPlaylistRenamePlaylist"/>
     <separator/>
     <menuitem name="QueuePlaylistPopup" action="QueuePlaylist"/>
+    <menuitem name="QueuePlaylistPopup" action="QueuePlaylist"/>
+    <menuitem name="QueuePlaylistPopup" action="QueuePlaylist"/>
+    <menuitem name="ShufflePlaylistPopup" action="ShufflePlaylist"/>
     <placeholder name="PlaylistSourcePopupPluginPlaceholder" />
     <separator/>
     <menuitem name="DeletePlaylistPopup" action="MusicPlaylistDeletePlaylist"/>
@@ -233,6 +236,7 @@
     <menuitem name="RenameAutoPlaylistPopup" action="MusicPlaylistRenamePlaylist"/>
     <separator/>
     <menuitem name="QueuePlaylistPopup" action="QueuePlaylist"/>
+    <menuitem name="ShufflePlaylistPopup" action="ShufflePlaylist"/>
     <placeholder name="AutoPlaylistSourcePopupPluginPlaceholder" />
     <separator/>
     <menuitem name="DeleteAutoPlaylistPopup" action="MusicPlaylistDeletePlaylist"/>