Add lttng_waiter utils

[lttng-tools.git] / src / common / waiter.h

diff --git a/src/common/waiter.h b/src/common/waiter.h
new file mode 100644 (file)
index 0000000..30eb38f
--- /dev/null
+++ b/src/common/waiter.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *               2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License, version 2.1 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * This code is originally adapted from userspace-rcu's urcu-wait.h
+ */
+
+#ifndef LTTNG_WAITER_H
+#define LTTNG_WAITER_H
+
+#define _LGPL_SOURCE
+
+#include <stdint.h>
+#include <urcu/wfstack.h>
+#include <stdbool.h>
+#include "macros.h"
+
+struct lttng_waiter {
+       struct cds_wfs_node wait_queue_node;
+       int32_t state;
+};
+
+LTTNG_HIDDEN
+void lttng_waiter_init(struct lttng_waiter *waiter);
+
+LTTNG_HIDDEN
+void lttng_waiter_wait(struct lttng_waiter *waiter);
+
+/*
+ * lttng_waiter_wake_up must only be called by a single waker.
+ * It is invalid for multiple "wake" operations to be invoked
+ * on a single waiter without re-initializing it before.
+ */
+LTTNG_HIDDEN
+void lttng_waiter_wake_up(struct lttng_waiter *waiter);
+
+#endif /* LTTNG_WAITER_H */