1 files changed, 81 insertions, 0 deletions
diff --git a/absl/cleanup/internal/cleanup.h b/absl/cleanup/internal/cleanup.h
new file mode 100644
index 00000000..b4c40737
--- /dev/null
+++ b/absl/cleanup/internal/cleanup.h
@@ -0,0 +1,81 @@
+// Copyright 2021 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_CLEANUP_INTERNAL_CLEANUP_H_
+#define ABSL_CLEANUP_INTERNAL_CLEANUP_H_
+
+#include <type_traits>
+#include <utility>
+
+#include "absl/base/internal/invoke.h"
+#include "absl/base/thread_annotations.h"
+#include "absl/utility/utility.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+namespace cleanup_internal {
+
+struct Tag {};
+
+template <typename Arg, typename... Args>
+constexpr bool WasDeduced() {
+  return (std::is_same<cleanup_internal::Tag, Arg>::value) &&
+         (sizeof...(Args) == 0);
+}
+
+template <typename Callback>
+constexpr bool ReturnsVoid() {
+  return (std::is_same<base_internal::invoke_result_t<Callback>, void>::value);
+}
+
+template <typename Callback>
+class Storage {
+ public:
+  Storage() = delete;
+
+  Storage(Callback callback, bool is_callback_engaged)
+      : callback_(std::move(callback)),
+        is_callback_engaged_(is_callback_engaged) {}
+
+  Storage(Storage&& other)
+      : callback_(std::move(other.callback_)),
+        is_callback_engaged_(
+            absl::exchange(other.is_callback_engaged_, false)) {}
+
+  Storage(const Storage& other) = delete;
+
+  Storage& operator=(Storage&& other) = delete;
+
+  Storage& operator=(const Storage& other) = delete;
+
+  bool IsCallbackEngaged() const { return is_callback_engaged_; }
+
+  void DisengageCallback() { is_callback_engaged_ = false; }
+
+  void InvokeCallback() ABSL_NO_THREAD_SAFETY_ANALYSIS {
+    std::move(callback_)();
+  }
+
+ private:
+  Callback callback_;
+  bool is_callback_engaged_;
+};
+
+}  // namespace cleanup_internal
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_CLEANUP_INTERNAL_CLEANUP_H_