[gnome-photos/wip/rishi/misc-fixes: 12/15] base-item, pipeline: Construct Pipeline asynchronously

[Debarshi Ray <debarshir src gnome org>]

commit 99bdc7bc9af12779ee2fc680cf53085b49452a59
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Dec 18 15:47:40 2015 +0100

    base-item, pipeline: Construct Pipeline asynchronously
    
    We will eventually try to restore any saved Pipeline by reading the XML
    from disk. Since there is no guarantee that the user's home directory
    will be on a local filesystem, we have to do it asynchronously.

 src/photos-base-item.c |   56 +++++++++++++++++++++++++++----------
 src/photos-pipeline.c  |   72 +++++++++++++++++++++++++++++++++++++++++++++--
 src/photos-pipeline.h  |    9 +++++-
 3 files changed, 117 insertions(+), 20 deletions(-)
---
diff --git a/src/photos-base-item.c b/src/photos-base-item.c
index 55c2de8..669f2c5 100644
--- a/src/photos-base-item.c
+++ b/src/photos-base-item.c
@@ -799,17 +799,6 @@ photos_base_item_load_buffer_async (PhotosBaseItem *self,
       gegl_node_link_many (priv->load, orientation, priv->buffer_sink, NULL);
     }
 
-  if (priv->edit_graph == NULL)
-    {
-      GeglNode *graph;
-
-      priv->edit_graph = gegl_node_new ();
-      priv->buffer_source = gegl_node_new_child (priv->edit_graph, "operation", "gegl:buffer-source", NULL);
-      priv->pipeline = photos_pipeline_new (priv->edit_graph);
-      graph = photos_pipeline_get_graph (priv->pipeline);
-      gegl_node_link (priv->buffer_source, graph);
-    }
-
   task = g_task_new (self, cancellable, callback, user_data);
   g_task_set_source_tag (task, photos_base_item_load_buffer_async);
 
@@ -900,6 +889,39 @@ photos_base_item_load_load_buffer (GObject *source_object, GAsyncResult *res, gp
 
 
 static void
+photos_base_item_load_pipeline (GObject *source_object, GAsyncResult *res, gpointer user_data)
+{
+  GTask *task = G_TASK (user_data);
+  PhotosBaseItem *self;
+  PhotosBaseItemPrivate *priv;
+  GeglNode *graph;
+  GCancellable *cancellable;
+  GError *error;
+
+  self = PHOTOS_BASE_ITEM (g_task_get_source_object (task));
+  priv = self->priv;
+
+  cancellable = g_task_get_cancellable (task);
+
+  error = NULL;
+  priv->pipeline = photos_pipeline_new_finish (res, &error);
+  if (error != NULL)
+    {
+      g_task_return_error (task, error);
+      goto out;
+    }
+
+  graph = photos_pipeline_get_graph (priv->pipeline);
+  gegl_node_link (priv->buffer_source, graph);
+
+  photos_base_item_load_buffer_async (self, cancellable, photos_base_item_load_load_buffer, g_object_ref 
(task));
+
+ out:
+  g_object_unref (task);
+}
+
+
+static void
 photos_base_item_pipeline_save_save (GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
   GTask *task = G_TASK (user_data);
@@ -1788,6 +1810,8 @@ photos_base_item_load_async (PhotosBaseItem *self,
   g_return_if_fail (PHOTOS_IS_BASE_ITEM (self));
   priv = self->priv;
 
+  g_return_if_fail (priv->edit_graph == NULL || priv->pipeline != NULL);
+
   task = g_task_new (self, cancellable, callback, user_data);
   g_task_set_source_tag (task, photos_base_item_load_async);
 
@@ -1802,10 +1826,12 @@ photos_base_item_load_async (PhotosBaseItem *self,
     }
   else
     {
-      photos_base_item_load_buffer_async (self,
-                                          cancellable,
-                                          photos_base_item_load_load_buffer,
-                                          g_object_ref (task));
+      priv->edit_graph = gegl_node_new ();
+      priv->buffer_source = gegl_node_new_child (priv->edit_graph, "operation", "gegl:buffer-source", NULL);
+      photos_pipeline_new_async (priv->edit_graph,
+                                 cancellable,
+                                 photos_base_item_load_pipeline,
+                                 g_object_ref (task));
     }
 
   g_object_unref (task);
diff --git a/src/photos-pipeline.c b/src/photos-pipeline.c
index 150d858..c938cbb 100644
--- a/src/photos-pipeline.c
+++ b/src/photos-pipeline.c
@@ -24,7 +24,6 @@
 #include <string.h>
 
 #include <glib.h>
-#include <gio/gio.h>
 
 #include "egg-counter.h"
 #include "photos-debug.h"
@@ -52,8 +51,11 @@ enum
   PROP_PARENT,
 };
 
+static void photos_pipeline_async_initable_iface_init (GAsyncInitableIface *iface);
 
-G_DEFINE_TYPE (PhotosPipeline, photos_pipeline, G_TYPE_OBJECT);
+
+G_DEFINE_TYPE_EXTENDED (PhotosPipeline, photos_pipeline, G_TYPE_OBJECT, 0,
+                        G_IMPLEMENT_INTERFACE (G_TYPE_ASYNC_INITABLE, 
photos_pipeline_async_initable_iface_init));
 EGG_DEFINE_COUNTER (instances, "PhotosPipeline", "Instances", "Number of PhotosPipeline instances");
 
 
@@ -200,10 +202,72 @@ photos_pipeline_class_init (PhotosPipelineClass *class)
 }
 
 
+static void
+photos_pipeline_async_initable_init_async (GAsyncInitable *initable,
+                                           gint io_priority,
+                                           GCancellable *cancellable,
+                                           GAsyncReadyCallback callback,
+                                           gpointer user_data)
+{
+  PhotosPipeline *self = PHOTOS_PIPELINE (initable);
+  GTask *task;
+
+  task = g_task_new (self, cancellable, callback, user_data);
+  g_task_set_source_tag (task, photos_pipeline_async_initable_init_async);
+
+  g_task_return_boolean (task, TRUE);
+  g_object_unref (task);
+}
+
+
+static gboolean
+photos_pipeline_async_initable_init_finish (GAsyncInitable *initable, GAsyncResult *res, GError **error)
+{
+  PhotosPipeline *self = PHOTOS_PIPELINE (initable);
+  GTask *task = G_TASK (res);
+
+  g_return_val_if_fail (g_task_is_valid (res, self), FALSE);
+  g_return_val_if_fail (g_task_get_source_tag (task) == photos_pipeline_async_initable_init_async, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  return g_task_propagate_boolean (task, error);
+}
+
+
+static void
+photos_pipeline_async_initable_iface_init (GAsyncInitableIface *iface)
+{
+  iface->init_async = photos_pipeline_async_initable_init_async;
+  iface->init_finish = photos_pipeline_async_initable_init_finish;
+}
+
+
+void
+photos_pipeline_new_async (GeglNode *parent,
+                           GCancellable *cancellable,
+                           GAsyncReadyCallback callback,
+                           gpointer user_data)
+{
+  g_async_initable_new_async (PHOTOS_TYPE_PIPELINE,
+                              G_PRIORITY_DEFAULT,
+                              cancellable,
+                              callback,
+                              user_data,
+                              "parent", parent,
+                              NULL);
+}
+
+
 PhotosPipeline *
-photos_pipeline_new (GeglNode *parent)
+photos_pipeline_new_finish (GAsyncResult *res, GError **error)
 {
-  return g_object_new (PHOTOS_TYPE_PIPELINE, "parent", parent, NULL);
+  GObject *ret_val;
+  GObject *source_object;
+
+  source_object = g_async_result_get_source_object (res);
+  ret_val = g_async_initable_new_finish (G_ASYNC_INITABLE (source_object), res, error);
+  g_object_unref (source_object);
+  return PHOTOS_PIPELINE (ret_val);
 }
 
 
diff --git a/src/photos-pipeline.h b/src/photos-pipeline.h
index 69dd81a..d0a6577 100644
--- a/src/photos-pipeline.h
+++ b/src/photos-pipeline.h
@@ -24,6 +24,7 @@
 #include <stdarg.h>
 
 #include <gegl.h>
+#include <gio/gio.h>
 
 G_BEGIN_DECLS
 
@@ -54,7 +55,13 @@ typedef struct _PhotosPipelineClass PhotosPipelineClass;
 
 GType                  photos_pipeline_get_type          (void) G_GNUC_CONST;
 
-PhotosPipeline        *photos_pipeline_new               (GeglNode *parent);
+void                   photos_pipeline_new_async         (GeglNode *parent,
+                                                          GCancellable *cancellable,
+                                                          GAsyncReadyCallback callback,
+                                                          gpointer user_data);
+
+PhotosPipeline        *photos_pipeline_new_finish        (GAsyncResult *res,
+                                                          GError **error);
 
 void                   photos_pipeline_add               (PhotosPipeline *self,
                                                           const gchar *operation,