Introduce SpinLock

lib/base/CMakeLists.txt

@@ -64,6 +64,7 @@ set(base_SOURCES
   shared-object.hpp
   singleton.hpp
   socket.cpp socket.hpp
+  spinlock.cpp spinlock.hpp
   stacktrace.cpp stacktrace.hpp
   statsfunction.hpp
   stdiostream.cpp stdiostream.hpp

lib/base/spinlock.cpp

@@ -0,0 +1,22 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#include "base/spinlock.hpp"
+#include <atomic>
+
+using namespace icinga;
+
+void SpinLock::lock()
+{
+	while (m_Locked.test_and_set(std::memory_order_acquire)) {
+	}
+}
+
+bool SpinLock::try_lock()
+{
+	return !m_Locked.test_and_set(std::memory_order_acquire);
+}
+
+void SpinLock::unlock()
+{
+	m_Locked.clear(std::memory_order_release);
+}

lib/base/spinlock.hpp

@@ -0,0 +1,35 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#ifndef SPINLOCK_H
+#define SPINLOCK_H
+
+#include <atomic>
+
+namespace icinga
+{
+
+/**
+ * A spin lock.
+ *
+ * @ingroup base
+ */
+class SpinLock
+{
+public:
+	SpinLock() = default;
+	SpinLock(const SpinLock&) = delete;
+	SpinLock& operator=(const SpinLock&) = delete;
+	SpinLock(SpinLock&&) = delete;
+	SpinLock& operator=(SpinLock&&) = delete;
+
+	void lock();
+	bool try_lock();
+	void unlock();
+
+private:
+	std::atomic_flag m_Locked = ATOMIC_FLAG_INIT;
+};
+
+}
+
+#endif /* SPINLOCK_H */