base: add blockade as derivate of lock

Issue #3612

repos/base/include/base/blockade.h

@@ -0,0 +1,36 @@
+/*
+ * \brief  Blockade primitives
+ * \author Alexander Boettcher
+ * \date   2020-01-24
+ */
+
+/*
+ * Copyright (C) 2020 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _INCLUDE__BASE__BLOCKADE_H_
+#define _INCLUDE__BASE__BLOCKADE_H_
+
+#include <base/lock.h>
+#include <util/noncopyable.h>
+
+namespace Genode { class Blockade; }
+
+
+class Genode::Blockade : Noncopyable
+{
+	private:
+		Lock _lock;
+
+	public:
+		explicit Blockade() : _lock(Lock::LOCKED) { }
+
+		void block() { _lock.lock(); }
+
+		void wakeup() { _lock.unlock(); }
+};
+
+#endif /* _INCLUDE__BASE__BLOCKADE_H_ */