Add and use new variants of pubsub_distill_iq_reply

Often, you don't care at all about what the iq reply contains, only
whether it's a result or an error. wocky_pubsub_distill_void_iq_reply()
deals with that case more clearly than the caller passing three NULL
arguments to wocky_pubsub_distill_iq_reply().

Additionally, there exist cases where you're interested in the reply's
body if it's present, but the reply being empty is not an error.
wocky_pubsub_distill_ambivalent_iq_reply() handles this case.

They are all implemented in terms of a slightly enhanced version of the
former body of wocky_pubsub_distill_iq_reply().

3 files changed, 127 insertions, 14 deletions

diff --git a/wocky/wocky-pubsub-helpers.c b/wocky/wocky-pubsub-helpers.c
index 56fb1c4..650b022 100644
--- a/wocky/wocky-pubsub-helpers.c
+++ b/wocky/wocky-pubsub-helpers.c
@@ -112,6 +112,60 @@ get_pubsub_child_node (WockyXmppStanza *reply,
 
   return TRUE;
 }
+
+static gboolean
+wocky_pubsub_distill_iq_reply_internal (GObject *source,
+    GAsyncResult *res,
+    const gchar *pubsub_ns,
+    const gchar *child_name,
+    gboolean body_optional,
+    WockyXmppNode **child_out,
+    GError **error)
+{
+  WockyXmppStanza *reply;
+  gboolean ret = FALSE;
+
+  if (child_out != NULL)
+    *child_out = NULL;
+
+  /* Superlative news out of the 00:04 to Cambridge: earlier today, an
+   * asynchronous method call announced its plans to bring a node to The
+   * People's Republic of Wocky.
+   */
+  reply = wocky_porter_send_iq_finish (WOCKY_PORTER (source), res, error);
+
+  if (reply == NULL)
+    return FALSE;
+
+  if (!wocky_xmpp_stanza_extract_errors (reply, NULL, error, NULL, NULL))
+    {
+      ret = TRUE;
+
+      if (pubsub_ns != NULL)
+        {
+          /* A force of a thousand function calls will anchor the node to
+           * a resplendent out parameter modeled on the Dear Leader's hand.
+           */
+          ret = get_pubsub_child_node (reply, pubsub_ns, child_name, child_out,
+              error);
+
+          /* The People's Great and Harmonious Node Pointer of Peter
+           * Saint-Andre will conclude the most astonishing stanza breakdown
+           * ever witnessed by man.
+           */
+          if (!ret && body_optional)
+            {
+              /* “The stanza is perfect. We have already succeeded.” */
+              ret = TRUE;
+              g_clear_error (error);
+            }
+        }
+    }
+
+  g_object_unref (reply);
+  return ret;
+}
+
 /**
  * wocky_pubsub_distill_iq_reply:
  * @source: a #WockyPorter instance
@@ -141,18 +195,66 @@ wocky_pubsub_distill_iq_reply (GObject *source,
     WockyXmppNode **child_out,
     GError **error)
 {
-  WockyXmppStanza *reply = wocky_porter_send_iq_finish (
-      WOCKY_PORTER (source), res, error);
-  gboolean ret = FALSE;
-
-  if (reply == NULL)
-    return FALSE;
+  return wocky_pubsub_distill_iq_reply_internal (source, res, pubsub_ns,
+      child_name, FALSE, child_out, error);
+}
 
-  if (!wocky_xmpp_stanza_extract_errors (reply, NULL, error, NULL, NULL) &&
-      (pubsub_ns == NULL /* no child expected */ ||
-       get_pubsub_child_node (reply, pubsub_ns, child_name, child_out, error)))
-    ret = TRUE;
+/**
+ * wocky_pubsub_distill_void_iq_reply:
+ * @source: a #WockyPorter instance
+ * @res: a result passed to the callback for wocky_porter_send_iq_async()
+ * @error: location at which to store an error if the call to
+ *         wocky_porter_send_iq_async() returned an error, or if the reply was
+ *         an error
+ *
+ * Helper function to finish a wocky_porter_send_iq_async() operation where no
+ * pubsub child is expected in the resulting reply.
+ *
+ * Returns: %TRUE if the IQ was a success; %FALSE if
+ *          sending the IQ failed or the reply had type='error',
+ *          with @error set appropriately.
+ */
+gboolean
+wocky_pubsub_distill_void_iq_reply (GObject *source,
+    GAsyncResult *res,
+    GError **error)
+{
+  return wocky_pubsub_distill_iq_reply_internal (source, res, NULL, NULL, TRUE,
+      NULL, error);
+}
 
-  g_object_unref (reply);
-  return ret;
+/**
+ * wocky_pubsub_distill_ambivalent_iq_reply:
+ * @source: a #WockyPorter instance
+ * @res: a result passed to the callback for wocky_porter_send_iq_async()
+ * @pubsub_ns: the namespace of the <pubsub/> node accepted in this reply (such
+ *              WOCKY_XMPP_NS_PUBSUB)
+ * @child_name: the name of the child of <pubsub/> accepted in this reply (such
+ *              as "subscriptions")
+ * @child_out: location at which to store a pointer to the node named
+ *             @child_name, if is found, or to be set to %NULL if it is not
+ *             found
+ * @error: location at which to store an error if the call to
+ *         wocky_porter_send_iq_async() returned an error, or if the reply was
+ *         an error
+ *
+ * Helper function to finish a wocky_porter_send_iq_async() operation
+ * and extract a particular pubsub child from the resulting reply, if it is
+ * present. This is like wocky_pubsub_distill_iq_reply(), but is ambivalent as
+ * to whether the <pubsub/> structure has to be included.
+ *
+ * Returns: %TRUE if the IQ was a success; %FALSE if
+ *          sending the IQ failed or the reply had type='error',
+ *          with @error set appropriately.
+ */
+gboolean
+wocky_pubsub_distill_ambivalent_iq_reply (GObject *source,
+    GAsyncResult *res,
+    const gchar *pubsub_ns,
+    const gchar *child_name,
+    WockyXmppNode **child_out,
+    GError **error)
+{
+  return wocky_pubsub_distill_iq_reply_internal (source, res, pubsub_ns,
+      child_name, TRUE, child_out, error);
 }
diff --git a/wocky/wocky-pubsub-helpers.h b/wocky/wocky-pubsub-helpers.h
index f568221..65800e1 100644
--- a/wocky/wocky-pubsub-helpers.h
+++ b/wocky/wocky-pubsub-helpers.h
@@ -39,4 +39,15 @@ gboolean wocky_pubsub_distill_iq_reply (GObject *source,
     WockyXmppNode **child_out,
     GError **error);
 
+gboolean wocky_pubsub_distill_ambivalent_iq_reply (GObject *source,
+    GAsyncResult *res,
+    const gchar *pubsub_ns,
+    const gchar *child_name,
+    WockyXmppNode **child_out,
+    GError **error);
+
+gboolean wocky_pubsub_distill_void_iq_reply (GObject *source,
+    GAsyncResult *res,
+    GError **error);
+
 #endif /* WOCKY_PUBSUB_HELPERS_H */
diff --git a/wocky/wocky-pubsub-node.c b/wocky/wocky-pubsub-node.c
index c2379e5..d9523fd 100644
--- a/wocky/wocky-pubsub-node.c
+++ b/wocky/wocky-pubsub-node.c
@@ -486,7 +486,7 @@ unsubscribe_cb (GObject *source,
   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (user_data);
   GError *error = NULL;
 
-  if (!wocky_pubsub_distill_iq_reply (source, res, NULL, NULL, NULL, &error))
+  if (!wocky_pubsub_distill_void_iq_reply (source, res, &error))
     {
       g_simple_async_result_set_from_error (simple, error);
       g_clear_error (&error);
@@ -554,7 +554,7 @@ delete_node_iq_cb (GObject *source,
   GSimpleAsyncResult *result = G_SIMPLE_ASYNC_RESULT (user_data);
   GError *error = NULL;
 
-  if (!wocky_pubsub_distill_iq_reply (source, res, NULL, NULL, NULL, &error))
+  if (!wocky_pubsub_distill_void_iq_reply (source, res, &error))
     {
       g_simple_async_result_set_from_error (result, error);
       g_clear_error (&error);