update ceph source to reef 18.1.2

[ceph.git] / ceph / src / jaegertracing / opentelemetry-cpp / sdk / include / opentelemetry / sdk / common / atomic_unique_ptr.h

diff --git a/ceph/src/jaegertracing/opentelemetry-cpp/sdk/include/opentelemetry/sdk/common/atomic_unique_ptr.h b/ceph/src/jaegertracing/opentelemetry-cpp/sdk/include/opentelemetry/sdk/common/atomic_unique_ptr.h
new file mode 100644 (file)
index 0000000..5945df9
--- /dev/null
+++ b/ceph/src/jaegertracing/opentelemetry-cpp/sdk/include/opentelemetry/sdk/common/atomic_unique_ptr.h
@@ -0,0 +1,87 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <atomic>
+#include <memory>
+
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace common
+{
+/**
+ * An owning pointer similar to std::unique_ptr but with methods for atomic
+ * operations.
+ */
+template <class T>
+class AtomicUniquePtr
+{
+public:
+  AtomicUniquePtr() noexcept {}
+
+  explicit AtomicUniquePtr(std::unique_ptr<T> &&other) noexcept : ptr_(other.release()) {}
+
+  ~AtomicUniquePtr() noexcept { Reset(); }
+
+  T &operator*() const noexcept { return *Get(); }
+
+  T *operator->() const noexcept { return Get(); }
+
+  /**
+   * @return the underly pointer managed.
+   */
+  T *Get() const noexcept { return ptr_; }
+
+  /**
+   * @return true if the pointer is null
+   */
+  bool IsNull() const noexcept { return ptr_.load() == nullptr; }
+
+  /**
+   * Atomically swap the pointer only if it's null.
+   * @param owner the pointer to swap with
+   * @return true if the swap was successful
+   */
+  bool SwapIfNull(std::unique_ptr<T> &owner) noexcept
+  {
+    auto ptr            = owner.get();
+    T *expected         = nullptr;
+    auto was_successful = ptr_.compare_exchange_weak(expected, ptr, std::memory_order_release,
+                                                     std::memory_order_relaxed);
+    if (was_successful)
+    {
+      owner.release();
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Atomically swap the pointer with another.
+   * @param ptr the pointer to swap with
+   */
+  void Swap(std::unique_ptr<T> &other) noexcept { other.reset(ptr_.exchange(other.release())); }
+
+  /**
+   * Set the pointer to a new value and delete the current value if non-null.
+   * @param ptr the new pointer value to set
+   */
+  void Reset(T *ptr = nullptr) noexcept
+  {
+    ptr = ptr_.exchange(ptr);
+    if (ptr != nullptr)
+    {
+      delete ptr;
+    }
+  }
+
+private:
+  std::atomic<T *> ptr_{nullptr};
+};
+}  // namespace common
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE