[gnome-photos] fetch-collections-job: Convert to async API

[Debarshi Ray <debarshir src gnome org>]

commit 707ba68170be700c1cb98942a779d99509d0dfb8
Author: Rafael Fonseca <r4f4rfs gmail com>
Date:   Thu Apr 14 16:24:35 2016 +0200

    fetch-collections-job: Convert to async API
    
    https://bugzilla.gnome.org/show_bug.cgi?id=764086

 src/photos-fetch-collection-state-job.c |   14 ++++-
 src/photos-fetch-collections-job.c      |   91 ++++++++++++++++++-------------
 src/photos-fetch-collections-job.h      |    9 ++-
 3 files changed, 72 insertions(+), 42 deletions(-)
---
diff --git a/src/photos-fetch-collection-state-job.c b/src/photos-fetch-collection-state-job.c
index e68cf16..bb17e71 100644
--- a/src/photos-fetch-collection-state-job.c
+++ b/src/photos-fetch-collection-state-job.c
@@ -169,12 +169,22 @@ photos_fetch_collection_state_job_emit_callback (PhotosFetchCollectionStateJob *
 
 
 static void
-photos_fetch_collection_state_job_job_collector (GList *collections_for_item, gpointer user_data)
+photos_fetch_collection_state_job_job_collector (GObject *source_object, GAsyncResult *res, gpointer 
user_data)
 {
   PhotosFetchCollectionStateJobData *data = user_data;
   PhotosFetchCollectionStateJob *self = data->job;
+  GError *error = NULL;
+  GList *collections_for_item;
+  PhotosFetchCollectionsJob *job = PHOTOS_FETCH_COLLECTIONS_JOB (source_object);
   const gchar *urn = data->urn;
 
+  collections_for_item = photos_fetch_collections_job_finish (job, res, &error);
+  if (error != NULL)
+    {
+      g_warning ("Unable to fetch collections: %s", error->message);
+      g_error_free (error);
+    }
+
   g_hash_table_insert (self->collections_for_items,
                        g_strdup (urn),
                        g_list_copy_deep (collections_for_item, (GCopyFunc) g_strdup, NULL));
@@ -274,7 +284,7 @@ photos_fetch_collection_state_job_run (PhotosFetchCollectionStateJob *self,
       self->running_jobs++;
       job = photos_fetch_collections_job_new (urn);
       data = photos_fetch_collection_state_job_data_new (self, urn);
-      photos_fetch_collections_job_run (job, photos_fetch_collection_state_job_job_collector, data);
+      photos_fetch_collections_job_run (job, NULL, photos_fetch_collection_state_job_job_collector, data);
       g_object_unref (job);
     }
 }
diff --git a/src/photos-fetch-collections-job.c b/src/photos-fetch-collections-job.c
index f67f438..44e8fe7 100644
--- a/src/photos-fetch-collections-job.c
+++ b/src/photos-fetch-collections-job.c
@@ -39,11 +39,10 @@
 struct _PhotosFetchCollectionsJob
 {
   GObject parent_instance;
+  GError *queue_error;
   GList *collections;
-  PhotosFetchCollectionsJobCallback callback;
   PhotosTrackerQueue *queue;
   gchar *urn;
-  gpointer user_data;
 };
 
 struct _PhotosFetchCollectionsJobClass
@@ -62,29 +61,23 @@ G_DEFINE_TYPE (PhotosFetchCollectionsJob, photos_fetch_collections_job, G_TYPE_O
 
 
 static void
-photos_fetch_collections_job_emit_callback (PhotosFetchCollectionsJob *self)
-{
-  if (self->callback == NULL)
-    return;
-
-  (*self->callback) (self->collections, self->user_data);
-}
-
-
-static void
 photos_fetch_collections_job_cursor_next (GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
-  PhotosFetchCollectionsJob *self = PHOTOS_FETCH_COLLECTIONS_JOB (user_data);
+  GTask *task = G_TASK (user_data);
+  PhotosFetchCollectionsJob *self;
   TrackerSparqlCursor *cursor = TRACKER_SPARQL_CURSOR (source_object);
+  GCancellable *cancellable;
   GError *error;
   gboolean valid;
 
+  self = g_task_get_source_object (task);
+  cancellable = g_task_get_cancellable (task);
+
   error = NULL;
   valid = tracker_sparql_cursor_next_finish (cursor, res, &error);
   if (error != NULL)
     {
-      g_warning ("Unable to fetch collections: %s", error->message);
-      g_error_free (error);
+      g_task_return_error (task, error);
       goto end;
     }
 
@@ -96,42 +89,48 @@ photos_fetch_collections_job_cursor_next (GObject *source_object, GAsyncResult *
       self->collections = g_list_prepend (self->collections, urn);
 
       tracker_sparql_cursor_next_async (cursor,
-                                        NULL,
+                                        cancellable,
                                         photos_fetch_collections_job_cursor_next,
-                                        self);
+                                        g_object_ref (task));
+
+      g_object_unref (task);
       return;
     }
 
- end:
   self->collections = g_list_reverse (self->collections);
-  photos_fetch_collections_job_emit_callback (self);
+  g_task_return_pointer (task, self->collections, NULL);
+
+ end:
   tracker_sparql_cursor_close (cursor);
-  g_object_unref (self);
+  g_object_unref (task);
 }
 
 
 static void
 photos_fetch_collections_job_query_executed (GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
-  PhotosFetchCollectionsJob *self = PHOTOS_FETCH_COLLECTIONS_JOB (user_data);
+  GTask *task = G_TASK (user_data);
   TrackerSparqlConnection *connection = TRACKER_SPARQL_CONNECTION (source_object);
+  GCancellable *cancellable;
   TrackerSparqlCursor *cursor;
   GError *error;
 
+  cancellable = g_task_get_cancellable (task);
+
   error = NULL;
   cursor = tracker_sparql_connection_query_finish (connection, res, &error);
   if (error != NULL)
     {
-      g_warning ("Unable to fetch collections: %s", error->message);
-      g_error_free (error);
-      photos_fetch_collections_job_emit_callback (self);
-      return;
+      g_task_return_error (task, error);
+      goto out;
     }
 
   tracker_sparql_cursor_next_async (cursor,
-                                    NULL,
+                                    cancellable,
                                     photos_fetch_collections_job_cursor_next,
-                                    g_object_ref (self));
+                                    g_object_ref (task));
+
+ out:
   g_object_unref (cursor);
 }
 
@@ -152,6 +151,7 @@ photos_fetch_collections_job_finalize (GObject *object)
 {
   PhotosFetchCollectionsJob *self = PHOTOS_FETCH_COLLECTIONS_JOB (object);
 
+  g_clear_error (&self->queue_error);
   g_list_free_full (self->collections, g_free);
   g_free (self->urn);
 
@@ -180,7 +180,7 @@ photos_fetch_collections_job_set_property (GObject *object, guint prop_id, const
 static void
 photos_fetch_collections_job_init (PhotosFetchCollectionsJob *self)
 {
-  self->queue = photos_tracker_queue_dup_singleton (NULL, NULL);
+  self->queue = photos_tracker_queue_dup_singleton (NULL, &self->queue_error);
 }
 
 
@@ -210,34 +210,51 @@ photos_fetch_collections_job_new (const gchar *urn)
 }
 
 
+GList *
+photos_fetch_collections_job_finish (PhotosFetchCollectionsJob *self, GAsyncResult *res, GError **error)
+{
+  GTask *task = G_TASK (res);
+
+  g_return_val_if_fail (g_task_is_valid (res, self), NULL);
+  g_return_val_if_fail (g_task_get_source_tag (task) == photos_fetch_collections_job_run, NULL);
+  g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+
+  return g_task_propagate_pointer (task, error);
+}
+
+
 void
 photos_fetch_collections_job_run (PhotosFetchCollectionsJob *self,
-                                  PhotosFetchCollectionsJobCallback callback,
+                                  GCancellable *cancellable,
+                                  GAsyncReadyCallback callback,
                                   gpointer user_data)
 {
   GApplication *app;
+  GTask *task;
   PhotosQuery *query;
   PhotosSearchContextState *state;
 
+  task = g_task_new (self, cancellable, callback, user_data);
+  g_task_set_source_tag (task, photos_fetch_collections_job_run);
+
   if (G_UNLIKELY (self->queue == NULL))
     {
-      if (callback != NULL)
-        (*callback) (NULL, user_data);
-      return;
+      g_task_return_error (task, g_error_copy (self->queue_error));
+      goto out;
     }
 
-  self->callback = callback;
-  self->user_data = user_data;
-
   app = g_application_get_default ();
   state = photos_search_context_get_state (PHOTOS_SEARCH_CONTEXT (app));
 
   query = photos_query_builder_fetch_collections_query (state, self->urn);
   photos_tracker_queue_select (self->queue,
                                query->sparql,
-                               NULL,
+                               cancellable,
                                photos_fetch_collections_job_query_executed,
-                               g_object_ref (self),
+                               g_object_ref (task),
                                g_object_unref);
   photos_query_free (query);
+
+ out:
+  g_object_unref (task);
 }
diff --git a/src/photos-fetch-collections-job.h b/src/photos-fetch-collections-job.h
index 36f2873..041c651 100644
--- a/src/photos-fetch-collections-job.h
+++ b/src/photos-fetch-collections-job.h
@@ -39,8 +39,6 @@ G_BEGIN_DECLS
   (G_TYPE_CHECK_INSTANCE_TYPE ((obj), \
    PHOTOS_TYPE_FETCH_COLLECTIONS_JOB))
 
-typedef void (*PhotosFetchCollectionsJobCallback) (GList *, gpointer);
-
 typedef struct _PhotosFetchCollectionsJob      PhotosFetchCollectionsJob;
 typedef struct _PhotosFetchCollectionsJobClass PhotosFetchCollectionsJobClass;
 
@@ -49,9 +47,14 @@ GType                      photos_fetch_collections_job_get_type    (void) G_GNU
 PhotosFetchCollectionsJob *photos_fetch_collections_job_new         (const gchar *urn);
 
 void                       photos_fetch_collections_job_run         (PhotosFetchCollectionsJob *self,
-                                                                     PhotosFetchCollectionsJobCallback 
callback,
+                                                                     GCancellable *cancellable,
+                                                                     GAsyncReadyCallback callback,
                                                                      gpointer user_data);
 
+GList                     *photos_fetch_collections_job_finish      (PhotosFetchCollectionsJob *self,
+                                                                     GAsyncResult *res,
+                                                                     GError **error);
+
 G_END_DECLS
 
 #endif /* PHOTOS_FETCH_COLLECTIONS_JOB_H */