[grilo-plugins] tracker: Support favorite read/write

[Victor Toso de Carvalho <victortoso src gnome org>]

commit bb3a85d9ed53335e7f64ce3ecd562ebc1bc27d11
Author: Marinus Schraal <mschraal scr gnome org>
Date:   Sun Nov 20 14:51:28 2016 +0100

    tracker: Support favorite read/write
    
    Support GRL_METADATA_KEY_FAVOURITE reading & writing in the tracker
    backend. The tracker ontology for this uses hasTag in combination with
    the nao:predefined-tag-favorite property, which doesn't line up directly
    with the boolean format Grilo uses. So either set the key with the given
    property or delete the tag completely.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=774748

 src/tracker/grl-tracker-source-api.c |   19 +++++++++++++---
 src/tracker/grl-tracker-utils.c      |   39 ++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 4 deletions(-)
---
diff --git a/src/tracker/grl-tracker-source-api.c b/src/tracker/grl-tracker-source-api.c
index 9df1a73..31faabe 100644
--- a/src/tracker/grl-tracker-source-api.c
+++ b/src/tracker/grl-tracker-source-api.c
@@ -156,6 +156,9 @@ GRL_LOG_DOMAIN_STATIC(tracker_source_result_log_domain);
   "?urn nie:url \"%s\" "                        \
   "}"
 
+#define TRACKER_DELETE_REQUEST                          \
+  "DELETE { <%s> %s } WHERE { <%s> a nfo:Media . %s }"
+
 #define TRACKER_SAVE_REQUEST                            \
   "DELETE { <%s> %s } WHERE { <%s> a nfo:Media . %s } " \
   "INSERT { <%s> a nfo:Media ; %s . }"
@@ -658,6 +661,7 @@ grl_tracker_source_writable_keys (GrlSource *source)
     keys = grl_metadata_key_list_new (GRL_METADATA_KEY_PLAY_COUNT,
                                       GRL_METADATA_KEY_LAST_PLAYED,
                                       GRL_METADATA_KEY_LAST_POSITION,
+                                      GRL_METADATA_KEY_FAVOURITE,
                                       NULL);
   }
   return keys;
@@ -951,10 +955,17 @@ grl_tracker_source_store_metadata (GrlSource *source,
   sparql_delete = grl_tracker_get_delete_string (sms->keys);
   sparql_cdelete = grl_tracker_get_delete_conditional_string (urn, sms->keys);
   sparql_insert = grl_tracker_tracker_get_insert_string (sms->media, sms->keys);
-  sparql_final = g_strdup_printf (TRACKER_SAVE_REQUEST,
-                                  urn, sparql_delete,
-                                  urn, sparql_cdelete,
-                                  urn, sparql_insert);
+
+  if (g_strcmp0 (sparql_insert, "") == 0) {
+    sparql_final = g_strdup_printf (TRACKER_DELETE_REQUEST,
+                                    urn, sparql_delete,
+                                    urn, sparql_cdelete);
+  } else {
+    sparql_final = g_strdup_printf (TRACKER_SAVE_REQUEST,
+                                    urn, sparql_delete,
+                                    urn, sparql_cdelete,
+                                    urn, sparql_insert);
+  }
 
   os = grl_tracker_op_initiate_set_metadata (sparql_final,
                                              (GAsyncReadyCallback) tracker_store_metadata_cb,
diff --git a/src/tracker/grl-tracker-utils.c b/src/tracker/grl-tracker-utils.c
index fd13041..4c296bc 100644
--- a/src/tracker/grl-tracker-utils.c
+++ b/src/tracker/grl-tracker-utils.c
@@ -92,6 +92,21 @@ set_date (TrackerSparqlCursor *cursor,
 }
 
 static void
+set_favourite (TrackerSparqlCursor *cursor,
+               gint                 column,
+               GrlMedia            *media,
+               GrlKeyID             key)
+{
+  const gchar *str = tracker_sparql_cursor_get_string (cursor, column, NULL);
+  gboolean is_favourite = FALSE;
+
+  if (str != NULL && g_str_has_suffix (str, "predefined-tag-favorite"))
+    is_favourite = TRUE;
+
+  grl_data_set_boolean (GRL_DATA (media), key, is_favourite);
+}
+
+static void
 set_title_from_filename (TrackerSparqlCursor *cursor,
                          gint                 column,
                          GrlMedia            *media,
@@ -386,6 +401,12 @@ grl_tracker_setup_key_mappings (void)
                       "nmm:trackNumber",
                       "nmm:trackNumber(?urn)",
                       "audio");
+
+  insert_key_mapping_with_setter (GRL_METADATA_KEY_FAVOURITE,
+                                  "nao:hasTag",
+                                  "nao:hasTag(?urn)",
+                                  "audio",
+                                  set_favourite);
 }
 
 tracker_grl_sparql_t *
@@ -480,6 +501,16 @@ gen_prop_insert_string (GString *gstr,
                             grl_data_get_float (data, assoc->grl_key));
     break;
 
+  case G_TYPE_BOOLEAN:
+    /* Special case for favourite tag, see comment in
+     * grl_tracker_tracker_get_insert_string for more details.
+     */
+    if (assoc->grl_key == GRL_METADATA_KEY_FAVOURITE) {
+      g_string_append_printf (gstr, "%s nao:predefined-tag-favorite",
+                              assoc->sparql_key_attr);
+    }
+    break;
+
   default:
     break;
   }
@@ -504,6 +535,14 @@ grl_tracker_tracker_get_insert_string (GrlMedia *media, const GList *keys)
       if (assoc == NULL)
         continue;
 
+      /* The favourite key is really setting or deleting a tag
+       * in tracker, so in the case of setting it to false skip
+       * the insert string creation step for this key completely.
+       */
+      if (assoc->grl_key == GRL_METADATA_KEY_FAVOURITE &&
+          !grl_media_get_favourite (media))
+        continue;
+
       if (!grl_data_has_key (GRL_DATA (media), key_id))
         continue;