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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 12:34:54 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 12:34:54 +0000
commit0915b3ef56dfac3113cce55a59a5765dc94976be (patch)
treea8fea11d50b4f083e1bf0f90025ece7f0824784a /lib/base/atomic.hpp
parentInitial commit. (diff)
downloadicinga2-0915b3ef56dfac3113cce55a59a5765dc94976be.tar.xz
icinga2-0915b3ef56dfac3113cce55a59a5765dc94976be.zip
Adding upstream version 2.13.6.upstream/2.13.6upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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1 files changed, 91 insertions, 0 deletions
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+/* Icinga 2 | (c) 2019 Icinga GmbH | GPLv2+ */
+
+#ifndef ATOMIC_H
+#define ATOMIC_H
+
+#include <atomic>
+#include <mutex>
+#include <type_traits>
+#include <utility>
+
+namespace icinga
+{
+
+/**
+ * Extends std::atomic with an atomic constructor.
+ *
+ * @ingroup base
+ */
+template<class T>
+class Atomic : public std::atomic<T> {
+public:
+ /**
+ * Like std::atomic#atomic, but operates atomically
+ *
+ * @param desired Initial value
+ */
+ inline Atomic(T desired)
+ {
+ this->store(desired);
+ }
+
+ /**
+ * Like std::atomic#atomic, but operates atomically
+ *
+ * @param desired Initial value
+ * @param order Initial store operation's memory order
+ */
+ inline Atomic(T desired, std::memory_order order)
+ {
+ this->store(desired, order);
+ }
+};
+
+/**
+ * Wraps any T into a std::atomic<T>-like interface that locks using a mutex.
+ *
+ * In contrast to std::atomic<T>, Locked<T> is also valid for types that are not trivially copyable.
+ * In case T is trivially copyable, std::atomic<T> is almost certainly the better choice.
+ *
+ * @ingroup base
+ */
+template<typename T>
+class Locked
+{
+public:
+ inline T load() const
+ {
+ std::unique_lock<std::mutex> lock(m_Mutex);
+
+ return m_Value;
+ }
+
+ inline void store(T desired)
+ {
+ std::unique_lock<std::mutex> lock(m_Mutex);
+
+ m_Value = std::move(desired);
+ }
+
+private:
+ mutable std::mutex m_Mutex;
+ T m_Value;
+};
+
+/**
+ * Type alias for std::atomic<T> if possible, otherwise Locked<T> is used as a fallback.
+ *
+ * @ingroup base
+ */
+template <typename T>
+using AtomicOrLocked =
+#if defined(__GNUC__) && __GNUC__ < 5
+ // GCC does not implement std::is_trivially_copyable until version 5.
+ typename std::conditional<std::is_fundamental<T>::value || std::is_pointer<T>::value, std::atomic<T>, Locked<T>>::type;
+#else /* defined(__GNUC__) && __GNUC__ < 5 */
+ typename std::conditional<std::is_trivially_copyable<T>::value, std::atomic<T>, Locked<T>>::type;
+#endif /* defined(__GNUC__) && __GNUC__ < 5 */
+
+}
+
+#endif /* ATOMIC_H */