tevent: add tevent_queue_wait_send/recv()

Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>

Signed-off-by: Gregor Beck <gbeck@sernet.de>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

2 files changed, 85 insertions, 0 deletions

diff --git a/lib/tevent/tevent.h b/lib/tevent/tevent.h
index 2bc4e2d7ad7..0705ff30bd4 100644
--- a/lib/tevent/tevent.h
+++ b/lib/tevent/tevent.h
@@ -1592,6 +1592,39 @@ size_t tevent_queue_length(struct tevent_queue *queue);
  */
 bool tevent_queue_running(struct tevent_queue *queue);
 
+/**
+ * @brief Create a tevent subrequest that waits in a tevent_queue
+ *
+ * The idea is that always the same syntax for tevent requests.
+ *
+ * @param[in]  mem_ctx  The talloc memory context to use.
+ *
+ * @param[in]  ev       The event handle to setup the request.
+ *
+ * @param[in]  queue    The queue to wait in.
+ *
+ * @return              The new subrequest, NULL on error.
+ *
+ * @see tevent_queue_wait_recv()
+ */
+struct tevent_req *tevent_queue_wait_send(TALLOC_CTX *mem_ctx,
+					  struct tevent_context *ev,
+					  struct tevent_queue *queue);
+
+/**
+ * @brief Check if we no longer need to wait in the queue.
+ *
+ * This function needs to be called in the callback function set after calling
+ * tevent_queue_wait_send().
+ *
+ * @param[in]  req      The tevent request to check.
+ *
+ * @return              True on success, false otherwise.
+ *
+ * @see tevent_queue_wait_send()
+ */
+bool tevent_queue_wait_recv(struct tevent_req *req);
+
 typedef int (*tevent_nesting_hook)(struct tevent_context *ev,
 				   void *private_data,
 				   uint32_t level,
diff --git a/lib/tevent/tevent_queue.c b/lib/tevent/tevent_queue.c
index 4750675802f..361fc7bc2e3 100644
--- a/lib/tevent/tevent_queue.c
+++ b/lib/tevent/tevent_queue.c
@@ -298,3 +298,55 @@ bool tevent_queue_running(struct tevent_queue *queue)
 {
 	return queue->running;
 }
+
+struct tevent_queue_wait_state {
+	uint8_t dummy;
+};
+
+static void tevent_queue_wait_trigger(struct tevent_req *req,
+				      void *private_data);
+
+struct tevent_req *tevent_queue_wait_send(TALLOC_CTX *mem_ctx,
+					  struct tevent_context *ev,
+					  struct tevent_queue *queue)
+{
+	struct tevent_req *req;
+	struct tevent_queue_wait_state *state;
+	bool ok;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct tevent_queue_wait_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	ok = tevent_queue_add(queue, ev, req,
+			      tevent_queue_wait_trigger,
+			      NULL);
+	if (!ok) {
+		tevent_req_nomem(NULL, req);
+		return tevent_req_post(req, ev);
+	}
+
+	return req;
+}
+
+static void tevent_queue_wait_trigger(struct tevent_req *req,
+					 void *private_data)
+{
+	tevent_req_done(req);
+}
+
+bool tevent_queue_wait_recv(struct tevent_req *req)
+{
+	enum tevent_req_state state;
+	uint64_t err;
+
+	if (tevent_req_is_error(req, &state, &err)) {
+		tevent_req_received(req);
+		return false;
+	}
+
+	tevent_req_received(req);
+	return true;
+}