libostree: Add _finish() API to async progress

Since OstreeAsyncProgress queues to the mainloop, we might "lose" the
last message.  Give callers a way to force a flush.

src/libostree/ostree-async-progress.c

@@ -63,6 +63,8 @@ struct OstreeAsyncProgress
   GHashTable *uint_values;
   GHashTable *uint64_values;
 
+  gboolean dead;
+
   char *status;
 };
 
@@ -184,9 +186,12 @@ ostree_async_progress_set_status (OstreeAsyncProgress       *self,
                                   const char                *status)
 {
   g_mutex_lock (&self->lock);
-  g_free (self->status);
-  self->status = g_strdup (status);
-  ensure_callback_locked (self);
+  if (!self->dead)
+    {
+      g_free (self->status);
+      self->status = g_strdup (status);
+      ensure_callback_locked (self);
+    }
   g_mutex_unlock (&self->lock);
 }
 
@@ -211,6 +216,9 @@ update_key (OstreeAsyncProgress   *self,
 
   g_mutex_lock (&self->lock);
 
+  if (self->dead)
+    goto out;
+
   if (g_hash_table_lookup_extended (hash, qkey, NULL, &orig_value))
     {
       if (orig_value == value)
@@ -270,3 +278,33 @@ ostree_async_progress_new_and_connect (void (*changed) (OstreeAsyncProgress *sel
   g_signal_connect (ret, "changed", G_CALLBACK (changed), user_data);
   return ret;
 }
+
+/**
+ * ostree_async_progress_finish:
+ * @self: Self
+ *
+ * Process any pending signals, ensuring the main context is cleared
+ * of sources used by this object.  Also ensures that no further
+ * events will be queued.
+ */
+void
+ostree_async_progress_finish (OstreeAsyncProgress *self)
+{
+  gboolean emit_changed = FALSE;
+
+  g_mutex_lock (&self->lock);
+  if (!self->dead)
+    {
+      self->dead = TRUE;
+      if (self->idle_source)
+        {
+          g_source_destroy (self->idle_source);
+          self->idle_source = NULL;
+          emit_changed = TRUE;
+        }
+    }
+  g_mutex_unlock (&self->lock);
+
+  if (emit_changed)
+    g_signal_emit (self, signals[CHANGED], 0);
+}