[sound-juicer] Use sj_metadata_list_albums_async() in reread_cd()

[Phillip Wood <pwood src gnome org>]

commit 60d4b851c5d4e1b713688d25256077543e0c5831
Author: Phillip Wood <phillip wood dunelm org uk>
Date:   Mon Jul 27 14:14:07 2015 +0100

    Use sj_metadata_list_albums_async() in reread_cd()
    
    This is the final step in making metadata retrieval cancellable so that
    the UI does not display stale metadata if the disc is ejected or the
    drive changed during metadata retrieval.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=753554

 src/sj-main.c |   68 +++++++++++++++++++++++++++++++-------------------------
 1 files changed, 38 insertions(+), 30 deletions(-)
---
diff --git a/src/sj-main.c b/src/sj-main.c
index 10ff372..29af801 100644
--- a/src/sj-main.c
+++ b/src/sj-main.c
@@ -100,6 +100,7 @@ static gint total_no_of_tracks;
 static gint no_of_tracks_selected;
 static AlbumDetails *current_album;
 static char *current_submit_url = NULL;
+static GCancellable *reread_cancellable; /* weak reference */
 
 gboolean autostart = FALSE, autoplay = FALSE;
 static char *device = NULL, **uris = NULL;
@@ -206,6 +207,10 @@ disc_ejected_cb (void)
       gtk_widget_get_mapped (multiple_album_dialog))
     gtk_dialog_response (GTK_DIALOG (multiple_album_dialog),
                          SJ_RESPONSE_EJECTED);
+  if (reread_cancellable != NULL) {
+    g_cancellable_cancel (reread_cancellable);
+    reread_cancellable = NULL;
+  }
   set_action_state ("re-read(false)");
   set_action_enabled ("re-read", FALSE);
   set_action_enabled ("submit-tracks", FALSE);
@@ -1155,10 +1160,30 @@ static void audio_volume_changed_cb (GSettings *settings, gchar *key, gpointer u
 }
 
 static void
-metadata_cb (SjMetadataGetter *m, GList *albums, GError *error)
+metadata_cb (GObject      *source,
+             GAsyncResult *result,
+             gpointer      user_data)
 {
+  SjMetadataGetter *mdg = SJ_METADATA_GETTER (source);
+  GError *error = NULL;
+  GList *albums;
+  gchar *url;
+
+  albums = sj_metadata_getter_list_albums_finish (mdg,
+                                                  result,
+                                                  &url,
+                                                  &error);
+  /* Check if this request was cancelled */
+  if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+    g_error_free (error);
+    return;
+  }
+
+  reread_cancellable = NULL;
+  set_action_enabled ("re-read", TRUE);
   set_action_state ("re-read(false)");
-  if (error) {
+
+  if (error != NULL) {
     gboolean realized;
     GtkWidget *dialog;
 
@@ -1174,16 +1199,15 @@ metadata_cb (SjMetadataGetter *m, GList *albums, GError *error)
     gtk_dialog_run (GTK_DIALOG (dialog));
     gtk_widget_destroy (dialog);
     update_ui_for_album (NULL);
+    g_error_free (error);
     return;
   }
 
   g_free (current_submit_url);
-  current_submit_url = sj_metadata_getter_get_submit_url (metadata);
+  current_submit_url = url;
   if (current_submit_url) {
     set_action_enabled ("submit-tracks", TRUE);
   }
-  set_action_enabled ("re-read", TRUE);
-
   /* Free old album details */
   g_clear_pointer (&current_album, (GDestroyNotify) album_details_free);
   /* Set the new current album pointer */
@@ -1236,8 +1260,6 @@ is_audio_cd (BraseroDrive *drive)
  */
 static void reread_cd (void)
 {
-  GError *error = NULL;
-
   set_action_state ("re-read(true)");
   set_action_enabled ("re-read", FALSE);
 
@@ -1258,29 +1280,16 @@ static void reread_cd (void)
     return;
   }
 
-  sj_metadata_getter_list_albums (metadata, &error);
+  if (reread_cancellable != NULL)
+    g_cancellable_cancel (reread_cancellable);
 
-  if (error) {
-    gboolean realized;
-    GtkWidget *dialog;
-
-    realized = gtk_widget_get_realized (main_window);
-    dialog = gtk_message_dialog_new (realized ? GTK_WINDOW (main_window) : NULL, 0,
-                                     GTK_MESSAGE_ERROR,
-                                     GTK_BUTTONS_CLOSE,
-                                     "%s", _("Could not read the CD"));
-    gtk_message_dialog_format_secondary_markup (GTK_MESSAGE_DIALOG (dialog),
-                                                "%s\n%s: %s",
-                                                _("Sound Juicer could not read the track listing on this 
CD."),
-                                                _("Reason"),
-                                                error->message);
-
-    gtk_dialog_run (GTK_DIALOG (dialog));
-    gtk_widget_destroy (dialog);
-    g_error_free (error);
-    update_ui_for_album (NULL);
-    return;
-  }
+  reread_cancellable = g_cancellable_new ();
+  sj_metadata_getter_list_albums_async (metadata,
+                                        reread_cancellable,
+                                        metadata_cb,
+                                        NULL);
+  /* reread_cancellable holds a weak reference */
+  g_object_unref (reread_cancellable);
 }
 
 static void
@@ -2119,7 +2128,6 @@ startup_cb (GApplication *app, gpointer user_data)
   brasero_media_library_start ();
 
   metadata = sj_metadata_getter_new ();
-  g_signal_connect (metadata, "metadata", G_CALLBACK (metadata_cb), NULL);
 
   sj_settings = g_settings_new ("org.gnome.sound-juicer");