1 files changed, 91 insertions, 8 deletions

diff --git a/ctdb/lib/tevent/tevent_queue.c b/ctdb/lib/tevent/tevent_queue.c
index 3715c35e4f..4750675802 100644
--- a/ctdb/lib/tevent/tevent_queue.c
+++ b/ctdb/lib/tevent/tevent_queue.c
@@ -144,17 +144,19 @@ static void tevent_queue_immediate_trigger(struct tevent_context *ev,
 	q->list->trigger(q->list->req, q->list->private_data);
 }
 
-bool tevent_queue_add(struct tevent_queue *queue,
-		      struct tevent_context *ev,
-		      struct tevent_req *req,
-		      tevent_queue_trigger_fn_t trigger,
-		      void *private_data)
+static struct tevent_queue_entry *tevent_queue_add_internal(
+					struct tevent_queue *queue,
+					struct tevent_context *ev,
+					struct tevent_req *req,
+					tevent_queue_trigger_fn_t trigger,
+					void *private_data,
+					bool allow_direct)
 {
 	struct tevent_queue_entry *e;
 
 	e = talloc_zero(req, struct tevent_queue_entry);
 	if (e == NULL) {
-		return false;
+		return NULL;
 	}
 
 	e->queue = queue;
@@ -163,16 +165,53 @@ bool tevent_queue_add(struct tevent_queue *queue,
 	e->trigger = trigger;
 	e->private_data = private_data;
 
+	/*
+	 * if there is no trigger, it is just a blocker
+	 */
+	if (trigger == NULL) {
+		e->triggered = true;
+	}
+
+	if (queue->length > 0) {
+		/*
+		 * if there are already entries in the
+		 * queue do not optimize.
+		 */
+		allow_direct = false;
+	}
+
+	if (req->async.fn != NULL) {
+		/*
+		 * If the callers wants to optimize for the
+		 * empty queue case, call the trigger only
+		 * if there is no callback defined for the
+		 * request yet.
+		 */
+		allow_direct = false;
+	}
+
 	DLIST_ADD_END(queue->list, e, struct tevent_queue_entry *);
 	queue->length++;
 	talloc_set_destructor(e, tevent_queue_entry_destructor);
 
 	if (!queue->running) {
-		return true;
+		return e;
 	}
 
 	if (queue->list->triggered) {
-		return true;
+		return e;
+	}
+
+	/*
+	 * If allowed we directly call the trigger
+	 * avoiding possible delays caused by
+	 * an immediate event.
+	 */
+	if (allow_direct) {
+		queue->list->triggered = true;
+		queue->list->trigger(queue->list->req,
+				     queue->list->private_data);
+		return e;
 	}
 
 	tevent_schedule_immediate(queue->immediate,
@@ -180,9 +219,48 @@ bool tevent_queue_add(struct tevent_queue *queue,
 				  tevent_queue_immediate_trigger,
 				  queue);
 
+	return e;
+}
+
+bool tevent_queue_add(struct tevent_queue *queue,
+		      struct tevent_context *ev,
+		      struct tevent_req *req,
+		      tevent_queue_trigger_fn_t trigger,
+		      void *private_data)
+{
+	struct tevent_queue_entry *e;
+
+	e = tevent_queue_add_internal(queue, ev, req,
+				      trigger, private_data, false);
+	if (e == NULL) {
+		return false;
+	}
+
 	return true;
 }
 
+struct tevent_queue_entry *tevent_queue_add_entry(
+					struct tevent_queue *queue,
+					struct tevent_context *ev,
+					struct tevent_req *req,
+					tevent_queue_trigger_fn_t trigger,
+					void *private_data)
+{
+	return tevent_queue_add_internal(queue, ev, req,
+					 trigger, private_data, false);
+}
+
+struct tevent_queue_entry *tevent_queue_add_optimize_empty(
+					struct tevent_queue *queue,
+					struct tevent_context *ev,
+					struct tevent_req *req,
+					tevent_queue_trigger_fn_t trigger,
+					void *private_data)
+{
+	return tevent_queue_add_internal(queue, ev, req,
+					 trigger, private_data, true);
+}
+
 void tevent_queue_start(struct tevent_queue *queue)
 {
 	if (queue->running) {
@@ -215,3 +293,8 @@ size_t tevent_queue_length(struct tevent_queue *queue)
 {
 	return queue->length;
 }
+
+bool tevent_queue_running(struct tevent_queue *queue)
+{
+	return queue->running;
+}