[tracker/wip/carlosg/tracker-3.0-api-breaks: 17/56] libtracker-sparql: Change arguments in TrackerNotifier::events signal

[Carlos Garnacho <carlosg src gnome org>]

commit 26a06e7bdebddc46a13a988e9668bd8659e0a126
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Dec 20 17:08:29 2019 +0100

    libtracker-sparql: Change arguments in TrackerNotifier::events signal
    
    We now emit service and graph as first arguments, and drop the rdf:type
    API, following the GraphUpdated signal from the Endpoint DBus interface.
    
    This makes the object and dbus signals match closer, enough for it to
    be straightforward to map one to the other.

 .../reference/libtracker-sparql/migrating-2to3.xml |  9 ++++
 src/libtracker-sparql/tracker-notifier.c           | 61 +++++++---------------
 2 files changed, 29 insertions(+), 41 deletions(-)
---
diff --git a/docs/reference/libtracker-sparql/migrating-2to3.xml 
b/docs/reference/libtracker-sparql/migrating-2to3.xml
index a23477eb2..f54b1cbd7 100644
--- a/docs/reference/libtracker-sparql/migrating-2to3.xml
+++ b/docs/reference/libtracker-sparql/migrating-2to3.xml
@@ -133,4 +133,13 @@ ORDER BY DESC ?count
       Notifiers are now created through tracker_sparql_connection_create_notifier().
     </para>
   </section>
+  <section>
+    <title>Different signature of TrackerNotifier::events signal</title>
+    <para>
+      A TrackerNotifier may hint changes across multiple endpoints (local or remote),
+      in consequence the signal additionally contains 2 string arguments, notifying
+      about the SPARQL endpoint the changes came from, and the SPARQL graph the changes
+      apply to.
+    </para>
+  </section>
 </chapter>
diff --git a/src/libtracker-sparql/tracker-notifier.c b/src/libtracker-sparql/tracker-notifier.c
index 37b3224ce..a532275a5 100644
--- a/src/libtracker-sparql/tracker-notifier.c
+++ b/src/libtracker-sparql/tracker-notifier.c
@@ -86,7 +86,8 @@ struct _TrackerNotifierPrivate {
 };
 
 struct _TrackerNotifierEventCache {
-       gchar *class;
+       gchar *service;
+       gchar *graph;
        TrackerNotifier *notifier;
        GSequence *sequence;
 };
@@ -94,7 +95,6 @@ struct _TrackerNotifierEventCache {
 struct _TrackerNotifierEvent {
        gint8 type;
        gint64 id;
-       const gchar *rdf_type; /* Belongs to cache */
        gchar *urn;
        guint ref_count;
 };
@@ -139,15 +139,12 @@ tracker_notifier_subscription_free (TrackerNotifierSubscription *subscription)
 }
 
 static TrackerNotifierEvent *
-tracker_notifier_event_new (gint64       id,
-                            const gchar *rdf_type)
+tracker_notifier_event_new (gint64 id)
 {
        TrackerNotifierEvent *event;
 
        event = g_new0 (TrackerNotifierEvent, 1);
        event->type = -1;
-       /* The type string belongs to the cache, and lives longer */
-       event->rdf_type = rdf_type;
        event->id = id;
        event->ref_count = 1;
        return event;
@@ -180,13 +177,15 @@ compare_event_cb (gconstpointer a,
 
 static TrackerNotifierEventCache *
 tracker_notifier_event_cache_new (TrackerNotifier *notifier,
-                                  const gchar     *rdf_class)
+                                  const gchar     *service,
+                                  const gchar     *graph)
 {
        TrackerNotifierEventCache *event_cache;
 
        event_cache = g_new0 (TrackerNotifierEventCache, 1);
        event_cache->notifier = g_object_ref (notifier);
-       event_cache->class = g_strdup (rdf_class);
+       event_cache->service = g_strdup (service);
+       event_cache->graph = g_strdup (graph);
        event_cache->sequence = g_sequence_new ((GDestroyNotify) tracker_notifier_event_unref);
 
        return event_cache;
@@ -197,7 +196,8 @@ tracker_notifier_event_cache_free (TrackerNotifierEventCache *event_cache)
 {
        g_sequence_free (event_cache->sequence);
        g_object_unref (event_cache->notifier);
-       g_free (event_cache->class);
+       g_free (event_cache->graph);
+       g_free (event_cache->service);
        g_free (event_cache);
 }
 
@@ -224,7 +224,7 @@ tracker_notifier_event_cache_get_event (TrackerNotifierEventCache *cache,
                        return event;
        }
 
-       event = tracker_notifier_event_new (id, cache->class);
+       event = tracker_notifier_event_new (id);
        g_sequence_insert_before (iter, event);
 
        return event;
@@ -403,7 +403,7 @@ tracker_notifier_event_cache_flush_events (TrackerNotifierEventCache *cache)
                if (priv->flags & TRACKER_NOTIFIER_FLAG_QUERY_URN)
                        tracker_notifier_query_extra_info (notifier, events);
 
-               g_signal_emit (notifier, signals[EVENTS], 0, events);
+               g_signal_emit (notifier, signals[EVENTS], 0, cache->service, cache->graph, events);
                g_ptr_array_unref (events);
        }
 }
@@ -421,10 +421,14 @@ graph_updated_cb (GDBusConnection *connection,
        TrackerNotifierEventCache *cache;
        GVariantIter *events;
        const gchar *graph;
+       gchar *service;
 
        g_variant_get (parameters, "(&sa(ii))", &graph, &events);
 
-       cache = tracker_notifier_event_cache_new (notifier, NULL);
+       service = g_strdup_printf ("dbus:%s", sender_name);
+       cache = tracker_notifier_event_cache_new (notifier, sender_name, graph);
+       g_free (service);
+
        handle_events (notifier, cache, events);
        g_variant_iter_free (events);
 
@@ -512,9 +516,10 @@ tracker_notifier_class_init (TrackerNotifierClass *klass)
                g_signal_new ("events",
                              TRACKER_TYPE_NOTIFIER, 0,
                              G_STRUCT_OFFSET (TrackerNotifierClass, events),
-                             NULL, NULL,
-                             g_cclosure_marshal_VOID__BOXED,
-                             G_TYPE_NONE, 1,
+                             NULL, NULL, NULL,
+                             G_TYPE_NONE, 3,
+                             G_TYPE_STRING | G_SIGNAL_TYPE_STATIC_SCOPE,
+                             G_TYPE_STRING | G_SIGNAL_TYPE_STATIC_SCOPE,
                              G_TYPE_PTR_ARRAY | G_SIGNAL_TYPE_STATIC_SCOPE);
 
        /**
@@ -642,32 +647,6 @@ tracker_notifier_event_get_id (TrackerNotifierEvent *event)
        return event->id;
 }
 
-/**
- * tracker_notifier_event_get_type:
- * @event: A #TrackerNotifierEvent
- *
- * Returns the RDF type that this notification event relates to, in their
- * expanded forms (for example,
- * <http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#Audio>).
- *
- * A resource may have multiple RDF types. In the case of changes to a
- * resource with multiple types, one event will be notified for each
- * RDF type the notifier is subscribed to.
- *
- * For performance reasons, Tracker only sends notifications for events that
- * are explicitly marked with the tracker:notify property in their ontology.
- *
- * Returns: the RDF type of the element
- *
- * Since: 1.12
- **/
-const gchar *
-tracker_notifier_event_get_type (TrackerNotifierEvent *event)
-{
-       g_return_val_if_fail (event != NULL, NULL);
-       return event->rdf_type;
-}
-
 /**
  * tracker_notifier_event_get_urn:
  * @event: A #TrackerNotifierEvent