[gnome-builder] snippets: improve async/finish snippets

[Christian Hergert <chergert src gnome org>]

commit e77414201bac8be6563b8ac7a6536d2a2003f0f0
Author: Christian Hergert <chergert redhat com>
Date:   Tue Jun 12 16:24:03 2018 -0700

    snippets: improve async/finish snippets

 data/snippets/gobject.snippets | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)
---
diff --git a/data/snippets/gobject.snippets b/data/snippets/gobject.snippets
index 1d6c55aeb..a3cc50186 100644
--- a/data/snippets/gobject.snippets
+++ b/data/snippets/gobject.snippets
@@ -414,11 +414,19 @@ snippet gsignal
                              ${8:0});
 snippet async
 - scope c
+       /**
+        * ${$2|functify}_$1_async:
+        * @self: an #$2
+        * @cancellable: (nullable): a #GCancellable
+        * @callback: a #GAsyncReadyCallback to execute upon completion
+        * @user_data: closure data for @callback
+        *
+        */
        void
        ${$2|functify}_${1:do_something}_async (${2:$filename|stripsuffix|camelize} *self,
-       ${$2|space} ${$1|space}          GCancellable *cancellable,
-       ${$2|space} ${$1|space}          GAsyncReadyCallback callback,
-       ${$2|space} ${$1|space}          gpointer user_data)
+       ${$2|space} ${$1|space}         GCancellable *cancellable,
+       ${$2|space} ${$1|space}         GAsyncReadyCallback callback,
+       ${$2|space} ${$1|space}         gpointer user_data)
        {
                g_autoptr(GTask) task = NULL;
 
@@ -426,21 +434,29 @@ snippet async
                g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
 
                task = g_task_new (self, cancellable, callback, user_data);
+               g_task_set_source_tag (task, ${$2|functify}_$1_async);
 
                $0
        }
 snippet finish
 - scope c
+       /**
+        * ${$2|functify}_$1_finish:
+        * @self: an #$2
+        * @result: a #GAsyncResult provided to callback
+        * @error: a location for a #GError, or %NULL
+        *
+        * Returns:
+        */
        gboolean
        ${$2|functify}_${1:do_something}_finish (${2:$filename|stripsuffix|camelize} *self,
-       ${$2|space} ${$1|space}           GAsyncResult *result,
-       ${$2|space} ${$1|space}           GError **error)
+       ${$2|space} ${$1|space}          GAsyncResult *result,
+       ${$2|space} ${$1|space}          GError **error)
        {
-               GTask *task = (GTask *)result;
-
                g_return_val_if_fail 
(${$filename|stripsuffix|functify|namespace|upper}_IS_${$filename|stripsuffix|class|functify|upper} (self), 
${3:FALSE});
+               g_return_val_if_fail (G_IS_TASK (result), $3);
 
-               return g_task_propagate_${4:boolean} (task, error);
+               return g_task_propagate_${4:boolean} (G_TASK (result), error);
        }
 snippet Private
 - desc Define a local for the GObject's private data.